Category Soviet x-plenes

In the mid-1960s the tactical arm of the Soviet Air Force (FA) needed a replacement for the elderly Yakovlev Yak-28 Brewer tactical bombers. The Yak-28 proved disappointing due to short range and severe restric­tions in the use of its weapons. By the mid-1960s, two important factors became evident. The first was the superiority of equivalent US designs, such as the General Dynamics F-111, due to higher performance, wider weapons range and outstandingly superior avionics. The second factor was the rapid development in surface-to-air missile technology; this required new tactical bomber to have supersonic low-level attack capa­bility, which placed high demands on airframe strength and required automatic terrain following capability.

Thus the Sukhoi design bureau (OKB) started work on a tactical bomber which would be the Soviet counterpart of the F-111. Initially the designers settled for mid-set wings with 40° leading-edge sweep. Receiving the in-house designation S-6, it was to have a top speed of 2,500 km/h (1,550 mph) and an all up weight of 20,000 kg (44,090 lb). The two crew members sat in tandem, and the two 7,200-kgp (15,870- lb st) Tumanskiy R-21F-300 afterburning turbojets were placed side-by – side in the rear fuselage, breathing through lateral air intakes.

It soon became evident that a conventional layout was inadequate for the project, and attention was turned to variable-geometry wings and lift-jets, the work proceeding in parallel on these two lines. A com­pletely new project designated T-6 was started. The first prototype, known as the T6-1, entered flight test on 2nd July 1967 with test pilot Vladimir S. Il’yushin at the controls. It had double-delta wings with 60° leading-edge sweep on the inner wings. The crew of two was seated side-by-side. Behind the cockpit were four Kolesov RD36-35 lift engines intended to improve field performance. Initially, two Tumanskiy R-27F2-300 cruise engines rated at 10,200 kgp (22,400 lb st) in full after­burner (again fed by variable lateral air intakes) were fitted; the air for the main engines was used to cool the lift-jets. The intended 11,200-kgp (24,750-lb st) Lyul’ka AL-21 F afterburning turbojets were fitted later.

The T6-1 was intended to carry air-to-surface missiles, unguided rockets, air-to-air missiles, bombs and other stores on four wing and two fuselage hardpoints. The wing span was 10.41m (34.14 ft), overall length 23.72 m (77.8 ft), height 6.373 m (20.9 ft) and wing area 45.33 sq. m (487.9 sq. ft). Maximum TOW was 26,100 kg (57,540 lb).

In the course of trials the Soviet Air Force changed its requirements; the ordnance load was increased to such an extent that lift engines were no longer viable. Also, the contradictory requirements of attack at transonic speeds at ground level and short-field capability were still there. Studies by the Central Aero- and Hydrodynamics Institute (TsAGI) showed that variable-geometry wings compared so favourably with every other possible layout that the Sukhoi OKB radically redesigned the T-6 less than six months after the first flight.

The second prototype, designated T6-2I (the T denoting izmenyayemaya [gheometriya], variable geometry) was completed in late 1969 and took to the air on 17th January 1970, again with Vladimir S. Il’yushin at the controls. The most important change was the new VG wings; they had four sweep settings: 16° for take-off and landing, 35° for loitering and cruise, 45° for manoeuvring and 69° for transonic/super – sonic flight. The fuselage was redesigned to increase fuel capacity and the air intakes were modified. The undercarriage was strengthened to let the aircraft carry an increased warload.

Tests of the T6-2I continued until 1976. The aircraft was soon joined by two more prototypes, the T6-3I and T6-4I. The results were encour­aging and in December 1971 the bomber entered series production at the Novosibirsk aircraft factory No. 153, receiving the service designa­tion Su-24; the in-house designation at the plant was “izdeliye (product) 41”. Initial operational capability was achieved in 1973 but it was not until 1975 that the Su-24 was formally included into the inventory. This version was known to the West by the NATO reporting name Fencer-A.

Modifications to the design were continually implemented as pro­duction progressed. E. g., wing span and wing area were increased soon after the beginning of production. Problems with the variable air intakes caused the intakes to be widened from the 4th production batch onwards (1972) when the to give an increased frontal area. Pressure from the WS to increase range led the OKB to increase the capacity of the number 1 fuel tank by 1,000 litres (220 Imp. gal.) starting with Batch 8, with a concurrent saving in weight which could be used for extra fuel. Operational experience showed the airframe was strong enough to carry more weapons, so two more hardpoints were added on the cen­treline, increasing the total to eight and the weapons load to 8,000 kg (17,680 lb). Weapons delivery was controlled by a PNS-24 Tigr naviga – tion/attack system enabling automatic flight along a pre-programmed route, weapons delivery and return to base.

Important changes were introduced in Batch 15 when the shape of the rear fuselage was redesigned to reduce drag. The box-like structure around the engine nozzles was replaced by a more rounded one with a deeply dished bottom between the nozzles and the brake parachute container was moved up. Extensions were added to the fin at the top and along the leading edge; the upper extension supported the A-711 navigation antenna and the leading edge now accommodated the RSDN-10 long-range radio navigation (LORAN) antenna and a cooling air intake for the generators. SPO-15 Beryoza (Birch) passive radar warning antennae in triangular fairings were placed on either side of the fin near the top. Other changes made at this time included the addition of leading-edge flaps to the outer wings and a reduction in the number of flap sections from three to two each side. This version was known to the West as the Fencer-B. An updated version with Beryoza (Birch) radar homing and warning system (RHAWS) antennae on the air intakes and near the top of the fin was code-named Fencer-C.

By 1975 the ongoing problems with the variable air intakes were finally solved by introducing fixed-area intakes from Batch 21 onwards, which also gave a weight saving of 200 kg (440 lb). Aircraft previously built with variable intakes had that control disconnected. As a result, top speed was effectively limited to 1,400 km/h (870 mph) or Mach 1.4 at sea level, except for very short emergency bursts of Mach 2. This was considered an acceptable trade-off against the elimination of previous problems, as 1,400 km/h at S/L had become the standard attack mode. Concurrently the wings were redesigned and given a different airfoil.

Although improvements were constantly incorporated, this did not affect the designation. It was not until 1975 that enough design changes took place to justify a new designation, T6-M or Su-24M (modifi tseerovannyy – modified). The eighth prototype of the Su-24 sans suf – fixe (T6-8) was converted into the Su-24M prototype and redesignated T6-8M, making its first flight on 24th June 1977. Production began in 1978; the aircraft was known at plant No. 153 as izdeliye 44; the NATO reporting name was Fencer-D.

Major changes were made to the avionics; the most fundamental one was the fitment of a new weapons control system – the PNS-24M Tigr NS. To accommodate the new equipment the forward fuselage was extended by 76 cm and lowered by 15 cm. Apart from the reshaped nose, the Su-24M could be identified by the straight air data boom at the tip of the radome replacing the F-shaped antenna assembly of ear­lier versions, nicknamed “goose” because of its shape. A Kai’ra-24M

(Grebe) day/night low light level TV system/laser designator was fitted, enabling the aircraft to carry laser – and TV-guided missiles and "smart bombs”. Also, the number of weapons carried was increased by the addition of a ninth hardpoint.

Combat capability was greatly improved by the addition of an in­flight refuelling system. An L-shaped FPSh-5M retractable IFR probe was installed just ahead of the cockpit to allow refuelling from another Su-24M fitted with a UPAZ-1A Sakhalin "buddy” refuelling pack or an ll’yushin IL-78/IL-78M Midas tanker. A new Karpaty (Carpathian moun­tains) defence system was introduced. Rounded boundary layer fences were initially fitted on the edge of the wing glove in line with the inner wing pylons; on some aircraft they housed chaff/flare dispensers. Later, when it was discovered that the wing fences improved longitudinal sta­bility but impaired directional stability, they were removed and the dis­pensers relocated to the upper rear fuselage.

In the mid-1980s permission was granted to export the Su-24M. In the late 1980s the OKB brought out an export version designated Su-24MK (kommehrcheskiy – “commercial”, i. e., export version) or izdeliye 44M. The first flight took place in 1987 and small-scale produc­tion commenced in 1988. The Su-24MK differed little from the standard Fencer-D – mainly in the avionics (particularly the IFF system) and weapons options; for example, the Su-24MK could carry more bombs – 38 FAB-100s compared with 34 on the Su-24M and four air-to-air mis­siles instead of two. All export Su-24MKs had angular wing fences, even though they were being removed at the time from Soviet Air Force Fencers. Sales reported so far are: to Iraq (24), Libya (15), Syria (12) and Iran (9).

In 1978 the OKB started full-scale development of the T-6MR recon­naissance version of the Su-24M. Intended as a successor to the out­dated and “short-legged" Yak-27R, Yak-28R and MiG-21 R, it was to operate at a depth of up to 400 km (250 miles) from the front line, day or night in any weather. The first flight took place in September 1980; two prototypes (the T6MR-26 and T6MR-34) were tested and the aircraft entered production and service as the Su-24MR ([samolyot-] razved – chik, reconnaissance aircraft) or izdeliye 48. The NATO code name was Fencer-E.

The comprehensive BKR-1 Shtyk (Bayonet) reconnaissance suite included a Shtyk MR-1 synthetic aperture side-looking airborne radar (SLAR) in the nose covering an area of 4 to 28 km (2.5-17.3 miles) from the centreline; a Zima (Winter) thermal imager; an Aist-M (Stork-M) TV camera; a Kadr (Photo exposure) PHOTINT system comprising an AP-102 panoramic camera and an AFA-A-100 oblique camera; an Efir-1 M (Ether-1 M; pronounced efeer) radiation monitor in a pod under the starboard outer wing; and a Tangahzh (Pitch, in the aeronautical sense) radio monitoring pod or a Shpil’-2M (Spire-2M) laser line-scan pod providing an image of almost photographic quality on the fuselage centreline. Data was recorded on tape but could be instantly transmit­ted to ground stations if required. Three underfuselage hardpoints and the built-in cannon were removed; two R-60 or R-60M air-to-air missiles could be carried under the port wing for self-defence.

Design work on the Su-24MP Fencer-F (izdeliye 46) electronic countermeasures (ECM) aircraft began in 1976; its mission was elec­tronic reconnaissance and neutralisation of the enemy’s air defence radars while escorting attack aircraft to their targets. The two prototypes were converted from Su-24M airframes (the T6M-25 and T6M-35) which were then redesignated T6MP-25 and T6MP-35; the P stands for postanovschchik pomekh – ECM platform. (Strictly speaking, the des­ignation ought to have been Su-24PR) The first flight took place in December 1979. Very little technical information relating to this variant has been released, but it is known to have a sophisticated suite for detecting, locating, analysing, identifying and jamming all known elec­tromagnetic emissions. The bulk of this work is handled by the Landysh (Lily of the valley) system and the aircraft can carry active jamming pods, such as the Los’ (Moose), Fasol’ (String bean) or Mimoza (Mimosette), under the fuselage with no apparent loss of performance. Only about twenty Su-24MPs were reportedly built.

Believe it or not, the Su-24 found peaceful uses as well. In the late 1990s the Flight Research Institute in Zhukovskiy operated two Su-24s – Fencer-A “15 White” (c/n 1515301) and Su-24M “11 White” (c/n 1141613) equipped with an air sampling pod for environmental moni­toring purposes.

The Su-24 achieved initial operational capability with the Soviet Air Force (WS) in 1973, even though official acceptance of the type was not given until 1975 – a move not uncommon in the USSR. After being issued to training units, Su-24s were delegated to regiments operating in the Western areas of the USSR and in the Far East. By assigning them to the Ukraine or the Baltic Republics the WS ensured they could be quickly deployed in times of trouble to Eastern Europe. Later, Su-24 units were stationed in East Germany, Poland and Hungary, but the main Fencer force remained in the USSR.

Among those types displaced from bomber divisions of the Tactical Aviation’s Air Armies were the obsolete ll’yushin IL-28 Beagle and Yak-28. A division usually included three bomber regiments, each hav­ing three squadrons with 10 aircraft per squadron. As production rate grew it was decided to equip some of the fighter-bomber divisions in the 4th, 24th and 30th Air Armies with the Su-24 capable of a more strate­gic role. These armies had been created in the early 1970s, reporting to the High Command of the Armed Forces to act as a strategic reserve (rather than to Army Fronts or Defence Districts where there was a risk of their aptitude for attacking behind the battle line being wasted in local situations). It was also easier to maintain a tighter control on the use of the nuclear bombs which these aircraft could carry.

On entering service with FA regiments that had previously operated such types as the Yak-28 and MiG-27, the Su-24 proved to be much more demanding in maintenance and service. Considering the com­plexity of its systems, this was hardly surprising and extra headaches were caused by the fact that this was the Soviet Air Force’s first experi­ence with computerised systems.

The Su-24 required appreciably more time and effort to prepare it for a sortie; on average, it needed 45 minutes work by 15 technicians. This effectively doubled ground crew workload per flight – an insup­portable situation which was tackled with alacrity. The demands of time could not be reduced because 45 minutes was the minimum time taken to spin up the gyroscopes in the navigation/attack system; some mis­sions requiring a greater degree of accuracy needed as much as 1 hour 20 minutes. Nonetheless, improvements could be made to ease the ground crews’ workload.

The biggest headaches to ground and air crews alike came from the avionics. Such was the need for this type of bomber that, as noted ear­lier, it was rushed into service before the State acceptance trials were completed. The complexity of the many systems and the use of an on­board computer stretched the knowledge and patience of the crews. Malfunctions were frequent and there were cases in the early stages of the Fencer’s career when whole squadrons were grounded for several days until remedies were found.

In-flight malfunction of the navigation and targeting system could all too easily put the crew at risk, especially on supersonic nap-of-the-earth (NOE) missions. At best the aircraft was saved but the target missed. It has been known for farms to lose valuable crops, buildings and even livestock when crews failed to realise there was a problem with the equipment and continued the attack in automatic mode, dropping their deadly load on whatever was unlucky enough to be there. There was a case of a crew getting lost, running out of fuel and having to eject because the airmen did not realise in time there was a fault.

The Sukhoi OKB went to great lengths to reduce pre-flight check time by providing easier access to engines, all systems, filters, gover­nors etc. Wheel changing was simplified by eliminating the need for lift­ing equipment. Special attention was given to the reduction of refuelling time by providing single-point pressure refuelling.

Once the teething troubles had been recognised and acknowl­edged, they were relatively easy to resolve. One particular cause for sat­isfaction was the aircraft’s ability to withstand bird strikes; a collision with a large eagle and another with seventeen sparrows resulted in no serious damage – at least not to the aircraft.

In spite of these difficulties, he pilots liked the Su-24, affectionately dubbing it “Chemodahn” (Suitcase) – an allusion to the slab-sided shape of its fuselage. They appreciated the good field of view, the well – planned flight deck and the automatic flight systems, especially on low – level operations. Flight handling was reasonably easy, even though the Su-24 could be less forgiving in certain circumstances. Slowly but sure­ly the restrictions imposed during the service introduction period were lifted until the Su-24 emerged as a first-rate tactical bomber.

The Su-24 has seen action in several armed conflicts, drawing first blood during the Afghan War where the type made its debut in the spring of 1984. With its weapons load of 7 tons (15,430 lb) – more than double that of other Soviet tactical strike aircraft, its impressive range and sophisticated mission avionics, the Fencer would make a valuable addition to the arsenal of the Soviet contingent helping the pro-Soviet Kabul government fight the Mujahideen rebels. Until then the Su-24 had been unavailable for the war, but the need for such an aircraft was now evident. It was decided to use the type from Soviet bases in Uzbekistan and Turkmenia. Thus, two regiments were seconded to the 40th Army, as the group of Soviet forces in Afghanistan was known. In early April 1984 the 143rd BAP (Bomber Regiment) with 26 Su-24Ms, then based in Georgia at Kopitnari (Kutaisi-1) airbase, was detached to Khanabad – the one in south-eastern Uzbekistan (near Karshi), not the one in Afghanistan. At the same time the 149th GvBAP (Guards Bomber Regiment) with Su-24 Fencer-Bs based at Nikolayevka AB in Kazakhstan was relocated to the fighter base at Koka’fdy near Termez, right beside the border.

The primary motive for the presence of Fencers on the Afghan the­atre of operations was the need to subdue Ahmad Shah Massoud, the most capable Mujahideen leader. As a rule, the Su-24s were used against area targets such as Mujahideen fortifications. Prior to the sor­tie, reconnaissance aircraft would photograph the target. Its coordinates would be fed into the bomber’s computer, and everything else was largely automatic; the PNS-24 nav/attack system would take the bomber there and drop the bombs. In the 149th GvBAR Sqn 1 aircraft usually carried four 500-kg bombs each and Sqn 2 and 3 aircraft were armed with twelve 250-kg bombs each; additionally, two drop tanks were always carried.

Su-24 operations in Afghanistan were not very intensive, since the ground forces were more in need of close air support than of carpet bombing. Nor were they particularly successful; the Su-24 had been designed with the relatively flat terrain of Western Europe in mind, and the radar (which could pinpoint small targets such as tanks) had trouble picking out the targets among the jumbled rocks. NOE flying was out of the question because of the many canyons and mountain ridges. Weapons efficiency was low, as guided bombs and missiles showed poor controllability in the rarefied air of the mountains. Bomb-aiming accuracy in level flight was poor; dropping bombs in a 20 to 30-degree dive produced better results but took the bombers within range of the enemy air defences. During the following months, attacks were carried out from altitudes in excess of 5,000 m (16,400 ft) – safely out of range of the Stinger man-portable air defence systems (MANPADS) supplied by the Western Alliance to the rebels.

The next time the Fencer appeared in Afghan skies was in 1988. At this stage, when the Soviet Union was already pulling out of the point­less conflict, Su-24 operations were mostly of a psy-war type, intended to exert a constant pressure on the Mujahideen and keep them busy. Sorties were flown not lower than at 7,000 m (22,965 ft) because of the omnipresent Stingers.

Generally the Su-24 had a good reliability record in Afghanistan. The few failures that did take place were mostly associated with hydraulics, flap and engine controls. Initially there were problems with the main nav/attack computer but these were quickly fixed as Afghan experience built up. Sometimes the drop tanks would refuse to give off fuel and had to be jettisoned – which the crews were reluctant to do, knowing that the tanks were in short supply. Because missions were prepared hastily, programming errors occurred and sometimes the navigation data mod­ules would even be installed on the wrong aircraft.

No Fencers were lost to enemy fire in the Afghan War. However, there were a few accidents and incidents. On the night of 13th December 1988 a 149th GvBAP forgot to set the wings and flaps for takeoff (they were always rotated to full sweep on the ground to save ramp space) and took off with the wings at maximum sweep. The fully fuelled and bombed-up aircraft managed to get unstuck at the last moment, crashing through the fence around the inner marker beacon and destroying the antenna in so doing; then it climbed away with a shocking 27-degree angle of attack and proceeded to the target. The rest of the sortie went normally, except for the flapless landing on return (the flap control unit had been annihilated when the aircraft hit a fence post). The crew was saved by the bomber’s rugged design and the fiat terrain around the base (eyewitnesses said the aircraft “could have run all the way to Afghanistan”!).

In December 1988 a 735th BAP Su-24 went off the side of the run­way when landing at Khanabad in a stiff crosswind. One of the main gear units hit a pothole and collapsed, rupturing a fuel line and causing a massive fire. The crew escaped but the WSO later died from burns.

Despite the Soviet withdrawal, the Su-24s stayed around for anoth­er month, ready to support Najibuilah’s government if the Mujahideen made an attack on Kabul. In the event, however, this was not needed and the aircraft returned to their home bases in March 1989, ending the Fencer’s Afghan involvement.

The type remained in active service in post-Soviet days. Apart from Russia, in the Commonwealth of Independent States (CIS) the Su-24 was operated by the air forces of Azerbaijan, Belarus, Kazakhstan, the Ukraine, Uzbekistan and Tajikistan.

The Russian Su-24s were also actively used in the First Chechen War (1994-96) and the Second Chechen War (1999-2001) against Chechen separatists. These missions did not always go without losses; three Fencers were shot down by MANPADS.

It is nearly 35 years since the first flight of the Su-24 prototype and 30 years since it first entered service with the WS. Despite many improvements to the airframe, avionics and systems, it does not incor­porate the latest state-of-the-art and no attempt has been made to ren­der it stealthy. Therefore, plans were in hand to replace it with a modern strike aircraft from the Sukhoi stable – the Su-34 (Su-32FN), a two-seat side-by-side derivative of the Su-27 Flanker interceptor. Yet budgetary constraints have caused these plans to be delayed, compelling the Russian Air Force to change its approach. Several Russian companies, such as Gefest&T, are offering mid-life updates for the Su-24M. Designated Su-24M2, the first upgraded aircraft having enhanced all- weather/night capability (38 White, c/n 1041643) was unveiled at the MAKS-2001 airshow. No doubt the introduction of the Su-34 will be a high-priority task, but shortage of funds (together with upgrade possi­bilities) will ensure that the Su-24M and MR will still be in Russian tacti­cal bomber and reconnaissance regiments for a few more years.

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Seen here at OKB-51 ‘s flight test facility in Zhukovskiy, the T6-1 (the first prototype of the Sukhoi T-6 tactical bomber) differed a lot from subsequent aircraft in the series. This view shows clearly the cranked delta wings similar to those of the Su – 15TM interceptor, the separately opening port and staboard canopy halves, the V-shaped window of the laser rangefinder ahead of the windscreen, the engine cooling air intakes on the rear fuselage and the land – ing/taxi lights on the sides of the nose. The closed dorsal intakes of the buried Kolesov RD36-35 lift jets in the fuselage are not vis­ible here.

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The T6-1 lacked a dielectric radome, fea­turing an all-metal nose ahead of the cock­pit windshield.

A “toad’s eye view” of the T6-1 seen head – on. Note the shape of the two-dimensional air intakes, the six weapons hardpoints, the straight pitot at the tip of the nose, the back-up pitot near the port wingtip and the nozzles of the lift jets between the under­fuselage pylons. The relatively narrow land­ing gear track is also noteworthy.

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A three-quarters rear view of the T6-1, showing the rectangular section of the fuselage forming a box around the engine nozzles, the lack of ventral fins, the brake parachute container at the base of the fin and the radar warning receiver (RWR) antenna near the fin tip. Note the unusual variant of the Soviet Air Force insignia on this aircraft with a pentagon incorporated into the middle of the star.

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After giving up on the use of lift jets which imposed an unacceptable weight penalty the OKB redesigned the T-6 radically, Incorporating variable-sweep wings to reconcile speed and field performance requirements. This is one of the prototypes of the Su-24 “sans suffixe”in the assembly shop of 0KB-51’s experimental plant in Moscow. This view shows clearly the wings at minimum sweep and the double-slotted flaps. Note that the rear fuselage, which was detachable for engine maintenance/ change, is still unpainted, indicating that the aircraft is undergoing conversion to a new variant (probably the Fencer-B proto­type). The aircraft in the background is the T10-1, the first prototype of the Su-27 fighter (NATO code name Flanker-A).

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The T6-2I (coded 62 Yellow) at the flight test facility during manufacturer’s tests. Note the warning markings near the radome (“Danger, HF radiation”) and the air intake bodies (“Danger, jet intake”). Note also the Sukhoi OKB’s “winged archer” logo beneath the cockpit and the red band near the top of the fin. The land­ing lights are still built into the forward fuselage sides. The all-movable stabilizers “bled” down to maximum nose-down posi­tion when hydraulic pressure fell off after engine shutdown.

The T6-2I at the Flight Research Institute (Lll) airfield in Zhukovskiy. All six hard – points are equipped with MBD3-U6-68 multiple ejector racks carrying 250-kg (551-lb) FAB-250 bombs. Due to take-off weight limitations the two MERs under the fuselage carry five bombs each instead of six; the total number of bombs is 34, equalling a warload of 8.5 tons (18,740 lb). Note the colour of the radome, the differ­ent Sukhoi OKB badge, three test mission markers and cruciform photo calibration markings beneath the cockpit and the blue fin stripe replacing the earlier red one. An ILS aerial is mounted above the air data boom carrying pitch and yaw sensor vanes.

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One more view of the fully loaded T6-2I at Zhukovskiy with wings at maximum sweep. As is the case with some Western strike air­craft, the pylons under the Su-24’s outer wings rotate as wing sweep chages, remaining parallel to the fuselage centre­line. This view shows well the intakes’ boundary layer splitter plates.

One of the Su-24 prototypes with the wings at minimum sweep. The aircraft carries 24 FAB-250s on MERs on the wing pylons and a pair of 500-kg (1,102-lb) FAB-500s on the fuselage stations, which equals an ord­nance load of 7 tons (15,430 lb).

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The sixth prototype Su-24 (T6-6) was coded 66 Yellow. Here the aircraft is armed with SPPU-6 gun pods with depressabie six-barrel 23-mm Gatling machine guns (here with the barrels at the maximum deflection of 45°) on the inner wing pylons, OFAB-250ShN low-drag bombs for low – level strike on the fuselage stations and Kh-23 rockets on the outer wing pylons. The T6-6I still had a straight air data boom with an ILS aerial above it and nose- mounted landing lights (they were moved to the wing roots on production aircraft); the fin top band was white.

Two views of the T6-27 (coded 27 White), another Fencer-B development aircraft, carrying three Kh-29 rockets on the inner wing and centreline pylons plus two Kh-23 rockets on the outer wing pylons. The red colour of the rockets identifies them as inert rounds for initial weapons trials; note the photo calibration markings on the rear fuselage. The wing fences were a recent addition at the time the pictures were taken – they have not been painted yet!

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The T6-8M, the prototype of the Su-24M (NATO code name Fencer-D), at the Lll air­field in Zhukovskiy in original guise. Note the extended nose, the extended wing leading edge root ECM fairings, the non­standard twin nose gear doors which remain open when the gear is down, the patch of bare metal and the absence of sensors on the underside of the nose where modifications have been made, the modified fin leading edge and the photo calibration markings on the fuselage. Despite the redesigned nose, the aircraft retains the "goose" typical of the initial – production Su-24 (compare this to the pro­duction aircraft on the opposite page).

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The T6-8M at a later stage of the trials wearing an unusual three-tone camouflage and the Sukhoi OKB “winged archer” badge beneath the cockpit. The sensor array under the nose has been reinstated. The aircraft carried no tactical code.

Another view of the camouflaged T6-8M, showing the shape of the rear fuselage around the engine nozzles and the ventral fuel jettison pipes under the nozzles. These features are identical to the final production version of the Su-24 «sans suf- fixe» (Fencer-C).

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An early-production Su-24M coded «07 White». Note the long straight air data probe at the tip of the radome and the wing fences (making the NATO reporting name Fencer oddly appropriate). The port canopy half is secured by a retaining rod to keep it from slamming down on some­body’s head or hands when there is no pressure in the hydraulic system.

Another view of Su-24M “07 White’’, show­ing the characteristic profile of the nose radome. Production Su-24s and Su-24Ms were normally painted light grey overall with white undersurfaces.

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Two views of Su-24s parked on a rain – lashed hardstand at Ostrov airbase near Pskov, north-western Russia. The base, whose name means “island” in Russian, hosts the Russian Navy’s Combat and Conversion Training Centre (i. e., opera­tional conversion unit).

The examples in these photos are repre­sentative of the very first production ver­sion known as the Fencer-A, as indicated by the boxy structure around the engine nozzles and the placement of the brake parachute container very close to the noz­zles. Oddly, the starboard airbrake-cum – mainwheel-well-door is open on all aircraft in the lineup while the port one is closed, as it should be on the ground. Note the fuel jettison pipe between the engine nozzles.

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Su-24 “29 White” seen at OstrovAB in 1998 is an example of the penultimate version of the Su-24 “sans suffixe” called Fencer-В in NATO parlance. Note the 3,000-litre (660 Imp. gal.) PTB-3000 drop tank suspended on the centreline pylon.

A trio of Fencer-As at Ostrov AB; note the different location and smaller size of the yellow radiation and air intake warning tri­angles. While the aircraft are in flyable stor­age, the resident Fencer-As were awaiting retirement and disposal on site.

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Su-24 “05 White” is an example of the final variant of the Su-24 “sans suffixe ” known as the Fencer-C. Theis version can be identi­fied by the ECM antenna fairings on the air intake bodies and the fin sides.

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Another view of Su-24s with PTB-3000 drop tanks under the wings in storage at OstrovABin 1998. The incredible fact that two neighbouring Fencer-As in the line-up carry the same tactical code, 29 White (quite apart from the Fencer-B shown on the preceding page!), is explained by the fact that the Su-24s were ferried to Ostrov for storage from various units and all three bombers obviously belonged to different regiments.

Close-up of the PTB-3000 on the centre­line hardpoint of Fencer-B “29 White”. The fins were set at more than 90° in order to provide adequate clearance between tank and wing/fuselage. Typically of the Soviet/Russian Air Force, drop tanks and such were marked with the aircraft’s tacti­cal code to stop them from being stolen and used on another aircraft – but clearly that did not always help; this drop tank comes from a sister ship coded 23! The yellow rectangles on the fuselage carry maintenance stencils.

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Front view of Su-24 Fencer-B “29 White”. The canopy is closed by a heavy canvas cover which protects the Perspex from the ultraviolet radiation of the sun, delaying the appearence of micro-cracks which gener­ate annoying reflections (this phenomenon is known as “silvering”).

The tails of these Fencer-As show how the Su-24 ’s rudder is cut away from below, with a radar warning receiver aerial at the base. On later versions the space between it and the fuselage was occupied by the brake parachute container which was moved up considerably.

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The Su-24’s wings were moved aft into fully swept position after landing to save space on the hardstand. This view shows the Su – 24’s large spoilers used for roll control.

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This Fencer-A (52 White) at Ostrov AB has had the entire forward fuselage wrapped in tarpaulins. The wraps bear the aircraft’s tactical code on a black circle. The aircraft is a late-production example, as indicated by the dorsal heat exchanger fairing usually found on later variants.

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As the wings are moved back into maximum sweep position the centre of gravity shifts aft, causing the Su-24 to assume a nose-up position. Fortunately, unlike some variable – geometry aircraft, even an unladen Fencer does not exhibit a tendency to tip over on its tail in this situation.

This Fencer-C undergoing maintenance has had a support placed under the tail – just in case. All wheel well doors are fully open. Note that skin panels mounting the centre portions of the ventral fins have been removed for access to some of the equip­ment in the rear fuselage.

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Fencer-A “26 White” at Ostrov AB. The slope behind it faced with concrete slabs functions both as a revetment wall and as a jet blast deflector, allowing the engines to be run after the aircraft has been aligned with the taxiway.

This late-production Fencer-A (note heat exchanger) operated by the Russian Navy’s Black Sea Fleet is rather more fortu­nate. When this picture was taken in 1998 it was fully operational and based at Gvardeyskoye AB in the Crimea which the Ukraine has leased to the Russian Naval Air Arm. Note the generally better surface fin­ish on this aircraft and the different design of the nosewheel mudguard. It is hard to say why a car tire has been place on top of the aircraft. The vehicle in the background is an APA-5 ground power unit on a Ural – 375D truck chassis.

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Su-24 Fencer-C “23 White” on the hard – stand at Gvardeyskoye AB in the summer of 1998. This view illustrates the large, high – set brake parachute container and the fin leading edge air intake which are charac­teristic of the Fencer-B/C.

Preparations are in hand for another day’s flying training over the Black Sea as a gag­gle of Su-24s basks in the sun at Gvardeyskoye AB. The nearest aircraft is provided not with the usual tarpaulin but with a modern cockpit cover made of reflective metallised fabric which also keeps the cockpit from turning into a steam bath in the summer season.

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Gvardeyskoye AB is a large and well – equipped base with a large flight line boasting an excellent surface and a con­crete-lined jet blast deflector, in post – Soviet days, however, it was not much used, and the arrival of the Russian Fencers (the Ukraine operates the type, too) was a welcome spell of activity. Note the bicycle leaned against the aircraft; ser­vicemen cycling around CIS airbases are a pretty common sight. Small wonder, as legging it around the place can get quite tiresome.

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Su-24s «01 White», «21 White» and «07 White» in the maintenance area at Gvardeyskoye AB. The second aircraft is unserviceable, being minus the port engine.

Another angle on the maintenance ramp, with a fourth aircraft («27 White») on the left. Note the trestle under the tail of Fencer-B «21 White». Fencer-Cs «01 White» and «27 White» are obviously recod­ed, the tactical code being applied over a blotch of darker paint.

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Fencer-C “28 White” (c/n 1715324) differs slightly in the design of the «goose» and undernose aerial from «27 White» on page 26. Interestingly, the port air intake cover comes from another example coded «26 White» (c/n 2215334).

A trailer-mounted ground power unit stands beside Fencer-C «01 White» to pro­vide electric power during maintenance.

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Many operational Su-24s show consider­able signs of wear and tear, as exemplified by Fencer-C «27 White» at Gvardeyskoye. Note the unit badge beneath the wind­screen. Again, the aircraft is obviously recoded, the part of the intake body with the tactical code making a marked contrast with the rest of the weather-stained air­frame.

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A pair of Su-24Ms coded «53 Red» and «57 Red» makes a banked turn over the Volga River near Akhtoobinsk, seat of the Air Force Research Institute. The camera ship is a slow transport, so the bombers fly with the wings at 16° to keep formation.

This view of a Su-24M shows that the wing and stabilator leading edges are parallel when the wings are at 69° maximum sweep. The radome on this particular example is unspeakably dirty, and more dirt emanates from the wing glove fairings near the wing pivots. The retractable FPSh-5M refuelling probe is positioned on the centreline ahead of the windscreen. Note the white colour­ing of the wing/stabilator leading edges and the offset position of the dorsal heat exchanger.

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Su-24M «67 White» parked at the Russian Navy Combat and Conversion Training Centre, OstrovAB. Note the red covers on the dipole aerial aft of the cockpit and the hemispherical sensor of the Mak-UFM missile warning sensor further aft.

Two more Su-24Ms, «64 White» and «68 White», under wraps at the Russian Navy Combat and Conversion Training Centre. Unlike the Fencer-As depicted earlier, these aircraft are not in storage but are actually based at Ostrov and belong to the 240th GvOSAP (Guards Independent Composite Air Regiment).

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Su-24M «66 White» is one of the Fencer-Ds belonging to the Russian Navy Combat and Conversion Training Centre. This example carries an L-080 Fantasmagoriya-A (Phantasm-A) electronic reconnaissance (ELI NT) pod on the centreline pylon.

Three more views of Su-24Ms «64 White» and «68 White». The main gear doors are fully open. Note the kinked nose gear door consisting of two parts, a characteristic feature of the Su-24M, and the curvature of the colour division line across the wing fences. Note that the tactical code is repeated on the «pig snout» plate at the tip of the nose pitot cover.

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In accordance with the 240th GvOSAP’s status Su-24M «66 White», seen here soak­ing under a horrendous downpour at Ostrov AB, wears a Guards badge (the old Soviet – style version) on the starboard side.

This late Fencer-D, a Batch 10 aircraft (c/n 1041611?) belonging to the 239th TsPAT (Aviation Hardware Demonstration Centre) at Kubinka AB, represents the export ver­sion designated Su-24MK. The blue tactical code is noteworthy, but the dark green/ dark earth tactical camouflage with pale blue undersurfaces similar to the one worn by Iraqi Air Force examples is even more unusual for a Russian Air Force Su-24. Note the lack of wing fences on this aircraft.

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«94 Blue» is prepared for a mission amid a jumble of ground support equipment that

comes with other Su-24s. Note the packed _______________________________________

brake parachutes on the left. 239th TsPAT Su-24MKs await the next sor-

tie. The Su-24 hardstand at Kubinka is well equipped, with an energy supply system obviating the need for mobile ground power units.

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Two more views of Su-24MK «94 Blue» (c/n 1241613) as is taxies out for a training sor­tie at Kubinka AB, the canopy still open. Unlike the other Fencers operated by the 239th TsPAT, this aircraft wears the stan­dard grey/white colour scheme. Also, this aircraft lacks the wing fences; these were removed from many Su-24s in service.

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«93 Blue», another camouflaged 239th TsPAT Su-24MK (c/n 1041623), taxies out for a training sortie. The aircraft is armed with S-25-OF heavy unguided rockets on the wing glove pylons and R-73 air-to-air missiles on the outer wing pylons. The «wet» centreline pylon mounts an UPAZ – 1A Sakhalin «buddy» refuelling pod allowing the Su-24 to refuel other tactical aircraft. The angular wing fences of «93 Blue» house APP-50 chaff/flare dispensers.

«94 Blue» is prepared for engine starting, using an APA-5D GPU in this instance; the brake parachute pack lies beside, ready for loading. The APA-5’s lateral cable booms swing out to the sides, allowing the vehicle to power up two aircraft at a time

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«92 Blue», the second of three camou­flaged Su-24MKs operated by the 239th TsPAT, fires up its Lyui’ka AL-21Fafterburn­ing turbofans at Kubinka on a bleak winter’s day. The aircraft shows signs of operational wear and tear, with weathered areas on the forward fuselage side touched up in fresher blue paint.

«92 Blue» taxies out, showing the steel plates protecting the inboard portions of the wing flaps from damage when they slide inside the wing gloves as wing sweep is changed.

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Due to the unit’s «showcase» nature the Su-24MKs at Kubinka AB were frequently displayed to various visiting military dele­gations and at open doors days. In the upper photo «91 Blue» is seen together with a Su-25 of the Nebesnyye Goosary (Celestial Hussars) display team which was disbanded soon afterwards.

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Two more views of Su-24MK «91 Blue» during displays at Kubinka. The aircraft is fitted with six MBD3-U6-68 MERs (two of them in tandem on the

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Su-24M «11 White» (c/n 1141613) belong­ing to the Sukhoi OKB performs a simulat­ed refuelling of Su-30 «597 White» (c/n 79371010101) belonging to the Ispytateli (Celestial Hussars) display team of the Flight Research Institute during the MAKS-97 airshow.

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SU-24MK «93 Blue» (c/n 1041623) refuels a sister aircraft coded «91 Blue» during an open doors day at Kubinka AB.

Two Su-24Ms can take on fuel simultane­ously from an IL-78 tanker, as demonstrat­ed by Fencer-Ds «17 White» and «19 White» formating with IL-78M «30 Blue» over Kubinka AB.

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Su-24M «45 Red» is one of several operat­ed by the 968th IISAP (Instructional & Test Composite Air Regiment) which is part of the Russian Air Force’s 4th TsBP і PLS (Combat and Conversion Training Centre) in Lipetsk. Note the unit badge and the five mission markers on the nose applied to mark successful live weapons training sor­ties.

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Su-24M «42 Red» is prepared for the day’s flying at Lipetsk AB. Like the other resident Fencers, the aircraft has been recoded. The GPU in this case is an APA-5DM based on a diesel-powered Ural-4320.

«41 Red», another 968th IISAP Su-24M (seen here sharing the ramp at Lipetsk with a Mikoyan MiG-29), wears 14 mission markers. It is equipped with a UPAZ-1A refuelling pod.

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Su-24M «41 Red» features APP-50 chaff/flare dispensers on the upper side of the rear fuselage to enhance the aircraft’s protection against heat-seeking missiles (see also page 44).

Another view of the flight line at Lipetsk.

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Interestingly, none of the 4th Combat and Conversion Training Centre’s Su-24Ms has the tactical code repeated on the fin, as is customary in the Russian Air Force. On the other hand, the tactical code is repeated on the nose gear door, which is certainly unusual.

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The flight line in Lipetsk is equipped with removable jet blast deflectors made of steel. This type of structure is more com­mon at Soviet/CIS airbases than the «built – in» version of the kind seen at OstrovAB.

Although the Su-24M’s entire nose ahead of the windshield is painted white, not all of it is dielectric. Here the extent of the actual radome is clearly visible, as the special radio-transparent white paint used on dielectric fairings has become so weath­ered as to turn a dirty grey colour.

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A This view of a Su-24M shows the wings at minimum sweep, the high-lift devices (slot­ted flaps and leading-edge slats) and the four underfuselage hardpoints (two in tan­dem and two side by side). The foremost pylon and the two side-by-side pylons are fitted in this case. The airbrakes/main gear doors are just about to close as the aircraft «cleans up» after take-off.

Su-24M «44 Red» «burns rubber» at the moment of touchdown in Lipetsk. This is one of several Fencer-Ds upgraded by the Russian avionics/weapons integrator Gefest & T. The mid-life update can be identified by the faired chaff-flare dis­pensers on top of the aft fuselage; the fair­ings have small air intakes at the front. The aircraft carries RBK-500 cluster bombs on the centreline pylons. ◄

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Close-up of the Gefest & T logo on the air intake ofSu-24M «40 Red», another exam­ple upgraded by the company. Note the «cross-hairs» in the middle of the Cyrillic letter F.

The Su-24Ms of the 4th TsBP і PLS are by far the most actively flying Fencers in Russia, surpassing even those the naval examples based at OstrovAB.

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The Su-24Ms of the 968th IISAP wear a badge depicting a rampant bull with the word «Vsegda» («always» in Russian). The badge signifies readiness to take on any adversary, anytime, anywhere (equvalent to the «Semper paratus» motto of some Western squadrons). A more unofficial interpretation is «we’ll have everybody, everywhere, every time and in every possi­ble way».

Su-24Ms «45 Red», «46 Red» and «40 Red» make a smoky flypast in echelon starboard formation. All three aircraft carry small bombs on the centreline; a minimum ord­nance load is enough for weapons training.

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The Su-24M served as a basis for the Su-24MR Fencer-E reconnaissance air­craft. This head-on view shows the recon­naissance version’s characteristic asym­metric external stores arrangement with a Efir – 1M electronic intelligence (ELINT) pod on the starboard wing pylon and a dual missile rack with two R-60 AAMs for self – defence under the port wing.

The Su-24MR has a much smaller nose radome, as revealed by the discolouration of the dielectric parts on the T6MR-1 pro­totype («26 White») converted from a Fencer-A (c/n 0115305). The space aft of it is occupied by a Shtyk MR-1 side-looking aircraft radar (SLAR) with elongated flush dielectric panels. The prototype lacked the IFR probe of production examples.

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The nose of the Su-24MR is painted white right up to the windshield, just as on the regular Fencer-D, in order to conceal its special nature from the adversary’s aerial reconnaissance and space surveillance assets. This example coded «15 White» carries an Shpil’-2M laser line-scan pod on the centreline pylon. The white «hump» on the dorsal heat exchanger fairing is not a cap of snow but a dielectric panel. Note that the drop tanks apparently come from another aircraft; even writing the tactical code in really huge digits does not help!

Su-24MR «12 White», seen here at the moment of rotation, carries a large photo reconnaissance/ELINT pod on the centre­line pylon.

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This Su-24MR coded «40 Yellow» (c/n 0941648) is used as a demonstrator by the Sukhoi Design Bureau and based in Zhukovskiy, hence the flashy colour scheme in the Russian flag colours of fhite, blue and red. Here the aircraft is fitted with a PHOTINT/ELINT pod; the open camera port is visible here.

Su-24MR c/n 0941648 in the static park of MosAeroShow-92. In this instance it car­ries an Shpil’-2M pod; this near head-on persoective illustrates the pod’s elliptical cross-section. Note that the AAM adapter under the starboard wing is the wrong one, i. e., it is intended for the starboard side (the upper missile should be on the outer side!).

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Su-24MR «40 Yellow» (c/n 0941648) – this time with no external stores – takes off from Zhukovskiy’s runway 12 fora demon­stration flight during one of the MAKS air – shows.

«40 Yellow» completes its landing roll on runway 30 at Zhukovskiy. The aircraft is a regular participant of the flying programme during Moscow airshows.

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Su-24MR «40 Yellow» passes in front of the crowd. Note the Vee shape of the colour division lines on the underside and the dirty marks sloping downwards from the stabila – tor pivots (a result of the stabilators’ habit of«bleeding» down to maximum deflection when the engines are inoperative).

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The other special mission derivative of the Su-24M was the Su-24MP Fencer-F elec­tronic countermeasures aircraft. This view shows the square-shaped dielectric panels on the sides of the nose (hiding jammer antennas), the characteristic ECM aerials under the nose and on the air intakes, and the centreline Fasol’ jammer pod.

The few Su-24MPs were stationed in the Far East and the Ukraine (the latter aircraft were retained by the newly-independent Ukraine after the break-up of the Soviet Union). Here, a Russian Air Force Su-24MP in wraps sits on a snowbound ramp at Lipetsk. Note that the outer wings are wrapped up, too.

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This 4th TsBP і PLS Su-24MP coded «15 White» is apparently due to awaken from winter sleep and make a training flight; mechanics are about to remove the canvas covers from the airframe.

«15 White», a Ukrainian Air Force Su-24MP, sits in front of a hardened aircraft shelter (HAS) at Chortkov AB. The immaculate fin­ish on this aircraft is noteworthy.

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Another view of Ukrainian AF Su-24MP «15 White». The nose gear doors are open for maintenance. The 118th OAPREB (Independent ECM Regiment) at Chortkov operating the type transitioned to the Su-24MP from the Yakovlev Yak-28PP.

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This Ukrainian Air Force Su-24M coded «19 White» carries UAF roundels on the forward fuselage (which makes an interesting com­parison with the aircraft on the opposite page) and dragon artwork. Note the L-080 Fanmtasmagoriya-A ELINTpod on the cen­treline station.

Ukrainian Air Force Su-24 Fencer-B «49 White» (c/n 1615324) undergoing mainte­nance at its home base, Chortkov AB. The radome swings open to port, revealing the two antenna dishes; the larger one is for the Puma fire control radar while the small one underneath is for the terrain following radar.

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Two more views of Ukrainian Air Force Su – 24 «49 White» (c/n 1615324) unbuttoned for maintenance, showing the positioning of the UAF roundels on the wings and the removable panels on the upper fuselage for access to the control runs and other systems.

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The nighbouring aircraft coded «50 White» is also being worked upon. The drop tank is inscribed «50 starboard» but the «5» has almost vanished – though it is hard to say why.

The Ukrainian Air Force also managed to keep some Fencer-As flying, as illustrated by «65 White» here. Note the variance in the shield-and-trident tail insignia on individual aircraft; the crudely overpainted red star is showing from under the UAF insignia on this one. The panels carrying the middle por­tions of the ventral fins are removed, show­ing that «65 White» is a bit unairworthy for the time being.

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Soviet/CIS Air Force tactical bomber units sometimes operated a mix of different Su-24 versions, as illustrated by Fencer-A «65 White» sharing the flight line with a Fencer-C. The removed access panels with the middle portions of the ventral fins are lying behind the aircraft.

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The Islamic Republic of Iran Air Force (IRIAF) was one of the few export cus­tomers for the Su-24. Apart from the Su – 24MKs delivered directly from Russia, the IRIAF retained several ex-Iraqi examples which sought shelter in neutral Iran at the closing stage of the 1991 Gulf War. Here, IRIAF Su-24MKs serialled 3-6853 (above) and 3-3810 (right) are seen at military hard­ware exhibitions at Teheran International airport.

Two IRIAF SU-24MK (3-6807 and 3-6811) cruise over the snow-covered mountains of northern Iran. These photos illustrate the two-tone camouflage worn by export Fencers.

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The rear fuselage and tail unit of the Fencer-A, the first production version of the Su-24, showing the low-set brake para­chute container. This particular aircraft serving as a ground instructional airframe at the Ukrainian Air Force Technical School near Kiev is the T6-19 development aircraft («619 White»; c/n 0215307?). Note the photo calibration marking on the tail.

This view clearly illustrates the difference in rear end treatment between the Fencer-A (background) and the Fencer-C. Note the antenna and cooling air intake built into the latter aircraft’s fin leading edge.

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A The rear fuselage and tail unit of the Su-24M (illustrated here by 239th TsPAT «92 Blue»), except for the shorter, upward – curved fuel jettison pipes.

Close-up of the Su-24M’s brake parachute container, with the radar homing and warn­ing system (RHAWS) antenna array above ◄

The outer wing pylons rotate as wing sweep changes, remaining parallel to the fuselage axis. This aircraft carries 32-round UB-32 rocket pods for firing 57-mm S-5 folding – fin aircraft rockets (FFARs).

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MBD3-U6-68 multiple ejector racks can be carried on any of the Su-24’s hard points. Up to six of these MERs can be fitted at a time for carrying FAB-250 HE bombs. The starboard one of the two elongated ventral fairings visible in the left photo houses a 30- mm Gryazev/Shipoonov GSh-6-30 six-bar­rel Gatling cannon; the muzzle opening is closed by «eyelid» shutters.

Double launcher adapters for R-73 air-to – air missiles can be carried on the outer wing pylons. These are usually fitted to the Su-24MR (here, «40 Yellow», c/n 0941648) and Su-24MP.

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The Su-24’s hefty wing pivot box is manu­factured as a singe whole with the fuse­lage. This is the port wing pivot and the riv­eted structure around it. Note the shallos strake which organses the airflow around the wing/fuselage joint.

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Up to three 3,000-litre (660 Imp. gal.) PTB-3000 drop tanks can be carried on the fuselage and inner wing hardpoints. Small canards with negative incidence are fitted at the front to facilitate separation when the tank is jettisoned.

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Close-up of the antenna dishes of the Orion-A fire control radar and the Rei’yef terrain following radar below it forming the PNS-24 Tigr navigation/attack avionics suite. The antenns are mounted on a solid frame which swings out to starboard for access to the radar sets. The stencils on the antenna dishes read «Attention! Tuned, do not touch». Note also the V-shaped win­dow of the TP-23E infra-red seeker.

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The Su-24 features a sharply swept two – piece windshield made of strong polycar­bonate. It is designed to minimise drag at high speed and withstand birdstrikes which are quite likely during low-level dashes. Note the PVD-7 pitot head in line with the windshield.

The two halves on the canopy can be opened individually, leaving a splitter run­ning down the middle. The construction number is normally stencilled on this (though not on this particular aircraft).

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Close-up of the faired centreline pylons carrying MBD3-U6-68 MERs.

Close-up of the Chaika (Seagull) under­nose forward-looking infra-red seeker (FLIR)/laser ranger window and Filin (Horned owl) ESM antennas.

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The instrument panel of the Su-24 featured illuminated push-button switches; some of the engine instruments are of the vertical strip type. The diagram in the centre with the aircraft silhouette and radial beams is the RHAWS indicator.

Overall view of the cockpit. The naviga – tor/weapons systems officer (WSO) sits on the right, detecting targets on the orange – coloured radar screen and the display above it. This aircraft is c/n 1215301 (note «12-01» stencilled in the WSO’s footwell).

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Another view of the cockpit with its conven­tional electromechanical flight instruments. The throttles are on the captain’s side con­sole.

As the Su-24 can only land safely with the wings at minimum sweep, a read emer­gency wing actuating handle is located on the l/l/SO’s instrument panel to the left of the airspeed indicator.

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Aptly coded «62 Yellow», the T6-2I was the first variable-geometry prototype.

The T6-27 during weapons trials. The aircraft is a Fencer-B.

«40 White», a 149th Guards Fighter Regiment Su-24 Fencer-B which saw action in Afghanistan, operating out of Kokaidy, Uzbekistan. Note the 13 mission markers.

Another Su-24M in a highly unusual colour scheme applied in the early 1990s. Note the «eyes» painted on the forward fuselage for bird-scaring. The Russian flag addition to the red star was short-lived.

A Ukrainian Air Force Su-24MR. Note the old-style round tail insignia and the Guards badge.

An Iraqi Air Force (a! Quwwat al-Jawwiya al-lraqiya) Su-24MK serialled 24246.

A production Su-24M with the wings at 69" sweep.

Purpose: Experimental jet bomber.

Design Bureau: OKB-1, Podberez’ye and later at Kimry, General Director from October 1948 S M Alekseyev.

The first official history of OKB-1 to be pub­lished (in Kryl’ya Rodiny for December 1987, written by I Sultanov) stated that it was led by Alekseyev, whose own OKB had been closed, and that this aircraft was ‘designed in close collaboration with CAHI (TsAGI), the leading experts on aerodynamics and struc­tures being V N Belyayev, AI Makarevskii, G P Svishchev and S A Khristianovich’. At the end it briefly noted that ‘a group from Ger­many, led by B Baade, participated…’ It would have been more accurate to explain that OKB-1 was specifically formed on 22nd October 1946 in order to put to use several hundred German design engineers, led by Prof Brunolf Baade and Hans Wocke, who had been forcibly taken with their families to a location 120km east of Moscow where they were put to work in a single large office block. For the first three years they were fully occu­pied on the Types 131 and 140 described pre­viously. However, mainly because of doubts that the forward-swept wing would ever be
made to work, even before they left Germany they had completed preliminary drawings for a bomber of similar size but with a conven­tional backswept wing. By 1948 this had be­come an official OKB-1 project, called 150. The original Chief Designer was P N Obrubov, but Alekseyev took his place when he arrived. Workers were increasingly transferred to the 150, which grew in size and weight from the original 25 tonnes to produce a bomber inter­mediate between the IL-28 and Tu-16. The brief specification issued by the WS called for a take-off weight between 38 and 47 tonnes, a maximum speed rising from 790 km/h at sea level to 970km/h at 5km, a service ceiling of 12.5km and a range varying with bomb load from 1,500 to 4,500km (932 to 2,796 miles). Only a single flight article was funded, and this had to wait a year for its en­gines. At last it was flown by Ya I Vernikov on 14th May 1951. On Flight 16 on 9th May 1952 the aircraft stalled on the landing approach, and though the aircraft was marginally re­pairable nobody bothered, because of the clearly greater potential of the Tu-88 (proto­type Tu-16). The dice were in any case loaded against a German-designed aircraft. In late 1953 Baade and most of the Germans re­
turned to their own country, where in Dres­den they formed a company called VEB which used the Type 150 as the [highly unsuitable] basis for the BB-152 passenger airliner.

A modern all-metal aircraft, the 150 had a shoulder-high wing with a fixed leading edge swept at 35°. As this wing had hardly any taper the tips were extraordinarily broad, leaving plenty of room for slim fairings housing the re­tracted tip landing gears. The concept of tan­dem centreline landing gears with small wheels at the wingtips had been evaluated with Alekseyev’s own I-215D. At rest the wing had anhedral of-4°, reduced to about -1° 20′ in flight. Each wing had two shallow fences from the leading edge to the slotted flap. Out­board were three-part ailerons. The fuselage was of circular section, tapering slightly aft of the wing to oval. Fixed seats were provided in the pressurized forward section for two pilots, a navigator/bombardier and a radio operator who also had periscopic control of a dorsal turret with two NR-23 cannon. Underthe floor was the RPB-4 navigation/bombing radar, with twin landing lamps recessed in the front. Behind this was the steerable twin-wheel nose gear. Next came the large bomb bay, 2.65m (8ft Sin) wide and high and 7m (23ft)

long, with a load limit of 6 tonnes (13,228 Ib). Next came the rear twin-wheel truck, which on take-off could be suddenly shortened to tilt the aircraft 3° 30′ nose-up for a clean liftoff. The large fin was swept at 45°, with a two-part rudder and carrying on top the 45°-swept tailplane and three-part elevators with dihe­dral of 8°. In the tail was a rear gunner with a turret mounting two NR-23 cannon. Under each wing was a forward-swept pylon carry­ing a Lyul’ka AL-5 turbojet rated at 4,600kg (lO. HOlb). A total of 35,875 litres (7,892 Im­perial gallons) of fuel was housed in eight cells along the upper part of the fuselage, and additional tanks could be carried in the bomb bay. On each side of the rear fuselage was a door-type airbrake. Like almost everything else these surfaces were operated electrical­ly, the high-power duplicated DC system in­cluding an emergency drop-out windmill generator. Each flight-control surface was op­erated by a high-speed rotary screwjack.

Though flight testing revealed some buffet­ing and vibration, especially at full power at high altitude, the numerous innovations in­troduced on this aircraft worked well. Never­theless, it would have been politically undesirable for what was essentially a Ger­man aircraft to be accepted for production. Thus, hitting the ground short of the runway was convenient.

Dimensions Span 24.1m 79 ft 1 in Length (excluding guns) 26. 74 m 87 ft 8% in Wing area 125m2 1,346ft2 Weights Empty 23,064kg 50,84715 Loaded 54 tonnes 119,00015 Performance Maximum speed at sea level, 850 km/h 528 mph at 10 km (32,808 ft) 930 km/h 578 mph Service ceiling about 13km 42,650ft No other data, except that design range (see a5ove) was exceeded.

Soviet X-Planes. in colour Posted by admin in Soviet x-plenes on November 9, 2015

Top: Mikoyan Ye-4 with RD-9I engine Centre: Mikoyan Ye-2A Bottom: Mikoyan Ye-5

Photographs on the opposite page: Top: Mikoyan I-3U in late 1956. Bottom: Mikoyan I-7U.

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Top: Mikoyan Ye-152/Awith K-9 missiles.

Right and bottom: Two views of the Mikoyan Ye-152P.

Photographs on the opposite page:

Top and centre: Two views of the Mikoyan Ye-8/2.

Bottom: Mikoyan Ye-50/3.

Photographs on the opposite page:

Top: Mikoyan Ye-152M (Ye-166) record version at Monino.

Centre. MiG-211/1 ‘Analog’.

Bottom: MiG-21PD (’23-31′).

Top: One ofthe Myasischev M-17 prototypes at Monino

Above, right and below: Three views of the Myasischev M-55.

Photographs on the opposite page:

Top and centre left: Two views of the Myasischev VM-T.

Centre left and bottom: Two views of the Sukhoi T-4 (‘101’).

Photographs on the opposite page:

Top and centre: Two views of the Sukhoi P-42 record aircraft.

Bottom left and right: Two views of the Sukhoi Su-27UB-PS test-bed.

Three views of the Sukhoi S-37, the lower two taken at the MAKS-99 air show. ,

Photographs on the opposite page: Top: Sukhoi Su-37 (T10M-11). Bottom: Sukhoi Su-37 ‘Berkut’.

Top: Tupolev Tu-155 test-bed at Zhukovskii.

Cen/re: YakovlevYak-141 at Khodynka.

Bottom: YakovlevYak-141 second prototype.

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Purpose: Originally, fast passenger transport; later, long-range experimental aircraft.

Design: SNII GVF; construction at GAZ (Factory) No 81, Moscow Tushino.

In the winter 1933-34 the GUGVF (chief ad­ministration of the civil air fleet) issued a re­quirement for a fast transport aircraft to carry 10 to 12 passengers. Curiously, the two proto­types built to meet this demand were both the work of immigrant designers, the Frenchman Laville (with ZIG-1) and the Italian Bartini. The latter had already produced drawings for a transport to cruise at 400km/h (248mph), which was well in advance of what the GVF had in mind. Always captivated by speed, Stalin decreed that a bomber version should be designed in parallel. Still in charge of de­sign at the SNII GVF, Bartini refined his study into the Stal’-7, the name reflecting its steel construction.

Strongly influenced by the Stalin decree, Bartini created a transport notable for its cramped and inconvenient fuselage, highly
unsuitable for passengers but excellent for bombs, and for long-range flight. The original structure was to be typical Bartini welded steel-tube trusses with fabric covering, but the stress calculations were impossibly diffi­cult, with 200 primary rigid welded intersec­tions between tubes of different diameters. In late 1934 the fuselage was redesigned as a light-alloy stressed-skin structure, with sim­pler connections to the unchanged wing.

Only one aircraft was built, in the work­shops ofZOK, the factory for GVF experimen­tal construction. The first flight was made on an unrecorded date in autumn 1936, the pilot being N P Shebanov. Performance was out­standing, and Shebanov proposed attempting a round-the-world flight. In 1937 the StaP-7 was fitted with 27 fuel tanks with a total ca­pacity of 7,400 litres (1,628 Imperial gallons, 1,955 US gallons). A maximum-range flight was then attempted, but – possibly because of structural failure of a landing gear – the air­craft crashed on take-off. Bartini was arrest­ed, and was in detention (but still designing, initially at OKB-4, Omsk) for 17 years.

The aircraft was repaired, and on 28th Au­gust 1939, at a slightly reduced weight, suc­cessfully made a closed-circuit flight of 5,068km (3,149 miles) in 12hrs Slmin (aver­age speed 404.936km/h, 251.62mph), to set an FAI Class record. The route was Moscow Tushino-Maloe Brusinskoe (Sverdlovsk re – gion)-Sevastopol-Tushino, and the crew comprised Shebanov, copilot VAMatveyev and radio/navigator N A Baikuzov. In Bartini’s absence, the project was seized by his op­portunist co-worker V G Yermolayev, who re­designed it into the outstanding DB-240 and Yer-2 long-range bomber.

The wing was typical Bartini, with pro­nounced straight taper and construction from complex spars built up from multiple steel tubes, almost wholly with fabric covering. Each wing comprised a very large centre sec­tion, with depth almost as great as that of the fuselage, terminating just beyond the engine nacelles 2.8m (9ft 2/4in) from the centreline, with sharp anhedral, and thinner outer panels with dihedral. The trailing edges carried split flaps and Frise ailerons, the left aileron having

a trim tab. One account says that the inverted – gull shape ‘improved stability and provided a cushion effect which reduced take-off and landing distance’, but its only real effect was to raise the wing on the centreline from the low to the mid position.

This was just what the fuselage did not need, because the massive deep spars formed almost impassable obstructions and eliminated any possibility of using the aircraft as a passenger airliner. The fuselage was a light-alloy structure, with an extremely
cramped cross-section with sides sloping in towards the top (almost a round-cornered tri­angle). Entry was via a very small door on the left of the rear fuselage. The cockpit in the nose seated pilots side by side, and had a glazed canopy with sliding side windows and the then-fashionable forward-raked wind­screen. Immediately behind the cockpit there was a station for the navigator/radio operator. The tail surfaces, made of dural/fabric, were of low aspect ratio, the elevators having tabs.

The engines were the 760hp M-100, these being the initial Soviet licence-built version derived by V Ya Klimov from the Hispano – Suiza 12Ybrs. They were installed in neat cowlings at the outer ends of the centre sec­tion, angled slightly outwards and driving pro­pellers with three metal blades which could have pitch adjusted on the ground. One ac­count states that wing-surface radiators were used, but it is obvious from photographs that ordinary frontal radiators were fitted, as in the Tupolev SB bomber. Plain exhaust stubs were fitted, though this may have scorched the wing fabric and one drawing shows ex­haust pipes discharging above the wing. In the course of 1938-39 the original engines were replaced by the derived M-103, rated at 860hp, which improved performance with heavy fuel loads. A hydraulic system was pro­vided to operate the flaps and the fully re­tractable main landing gears, each unit of which had a strong pair of main legs which hinged at mid-length, the unit then swinging back on twin forward radius arms (like a DC – 3 back-to-front). The castoring tailwheel was fixed. In the nose were twin landing lights.

The Stal’-7 was simply a sound aeroplane able to fly at what was in its day a very long way at high speed. As a transport it was in­convenient to the point of being useless, though it was supposed to be able to seat 12 passengers, and it was flawed by its basic lay­out and structure. The Soviet Union was right to take a licence for the Douglas DC-3. On the other hand, Yermolayev transformed the Stal’-7 into an outstanding long-range bomber.

Dimensions Span Length Wing area	23.0 m 16.0m 72.0 m2	75ft 5n in 52 ft 6 in 775ft2
Weights
Empty	4,800 kg	1 0,580 Ib
Loaded (originally)	7,200 kg	1 5,873 Ib
Maximum loaded ( 1 939)	1 1 ,000 kg	24,250 Ib

Performance Max speed at 3,000m (9,842 ft) 450km/h 280 mph Cruising speed 360/380 km/h 224/236 mph Service ceiling (disbelieved by Gunston) 1 1 ,000 m 36,090ft (on one engine, light weight) 4,500 m 14,764ft

Left: Two views of Stal’-7.

Purpose: To continue stratospheric-flight research with an aircraft superior to BOK-1. Design Bureau: Bureau of Special Design, Smolensk. Chief designer Chizhevskii.

Design of this aircraft began in 1936. The Tupolev RD was again used as the starting point, but with features intended to enable greater heights to be reached. The test pilots were Petrov and Stefanovskii. According to Shavrov the BOK-7 was first flown in 1938, and ‘showed the same characteristics as the BOK-1’. Several two-man crews, including such important long-distance pilots as Gro­mov, Yumashev, Danilin, Spirin, Baidukov, Belyakov and others, spent periods of several days sealed in the GK checking all aspects of human life in preparation for proposed high- altitude long-distance flights in the BOK-15. According to some historians the ultimate ob­jective was a high-altitude circumnavigation, and that the by-function designation of this aircraft was K-17, from Krugosvetnyi (round the world). Photographs originally thought to be of the BOK-7 are now known to show the BOK-11.

The BOK-7 had the full-span wing of the RD, and aft-retracting landing gears, but com­pared with the RD the legs were redesigned for much lighter gross weight, and fitted with single wheels. Attention was concentrated on the fuselage, which unlike the BOK-1 had the GK (pressure cabin) integral with the air­frame, the centre fuselage being a slim cylin­der sealed by gaskets and adhesives, and with grommets fitting round the control wires and other services passing through apertures in the wall. The normal oxygen supply to the pilot and pilot/observer ‘compensated for the insignificant amount of air escaping’. The sealed drum was fitted with two hemispheri­cal domes, the front with eight and the rear with six transparent portholes so that the oc­cupants could see out, with a better view than from the BOK-1. The GK was kept at pressure by a tapping from a centrifugal PTsN (super­charger) blower driven by step-up gears from the engine. The engine was an 890hp M-34FRN fitted with two TK (turbosuper­chargers). It is probable that these delivered compressed air to the PTsN which then fed the engine, the cabin supply being taken off a small bleed pipe. Shavrov states that ‘all sys­tems worked well’, and that the experiments were ‘very interesting’.

According to Shavrov this aircraft had ‘the first GK of the combined type’ with both a sealed compartment kept under pressure and an oxygen supply. Some accounts state that AI Filin at the NIl-WS worked out details of the proposed circumnavigation, in 100- hour stages, but that the project was aban­doned after he was arrested in 1939 and executed in Stalin’s Terror of 1940. This air­craft led to the BOK-8, BOK-11 and BOK-15, but it appears that no illustrations of it have been discovered.

Dimensions Span	34.0m	111 ft W in
Length	12.9m	42 ft 4 in
Wing area	87m2	936.5 ft2
Weights
Empty	3,900kg	8,598 Ib
No other data.

Purpose: To create a light transport with minimum operating cost.

Design Bureau: Kharkov Aviation Institute, Aviavnito brigade led by Aleksandr Alekseyevich Lazarev.

In the 1930s several Soviet designers pro­duced aircraft intended to demonstrate how much could be transported on the l00hp of an M-l 1 engine. These aircraft were as a class called Planerlyet (motor glider). This exam­ple had an unconventional configuration. It first flew on 14th September 1936, dual-con­trolled by V A Borodin and E I Schwartz. Eventually a control linkage was found which by 27th September enabled good turns to be made. Shavrov’s account ends with The

Aviavnito-3 after modification.

overall conclusion of the tests at Nil GVF (civil aviation test institute) was extremely posi­tive’, but nothing came of this one-off.

The Aviavnito-3 (often incorrectly called KhAI-3) was essentially an all-wing aircraft. The wing comprised a rectangular centre sec­tion, with the uncowled engine mounted on steel tubes on the front, to which were bolted two outer panels tapered on the leading edge. Aerofoil was V-106, with a t/c ratio of 14 per cent over the centre section, which had a chord of 5.0m (16ft Sin), tapering to 7 per cent at the tips, which incorporated 8° washout. Structurally, the centre section was KhMA steel tube covered by Dl Dural skin, while the outer panels were all wood, with truss ribs supporting closely spaced stringers. Along each outer edge of the centre section was a row of four seats, each front seat being for a pilot (the two pilots had to agree in advance which one should do the flying), covered by a row of sliding canopies. The flight controls comprised large unbalanced cable-operated surfaces divided into inner and outer sections to serve as ailerons and elevators. In addition, spoilers were recessed into the upper surface of each wingtip, driven by the pedals, to en­able co-ordinated turns to be made. A 2m2 (21.5ft2) fin and rudder were added, but it was hoped eventually to do without this. The sim­ple rubber-sprung main landing gears had 800 x 150mm tyres with brakes, and the large tailwheel could castor ±25°. Between the
rows of seats were four Dl tanks giving an 8-hour endurance. During development two additional seats were inserted on each side, pushing the pilots into noses projecting ahead of the wing. To balance these the vertical tail was significantly enlarged.

It is clear that this machine did everything expected of it, and that it was eventually de­veloped to fly safely and controllably. How­ever, even though they were much faster than anything else over vast areas devoid of sur­face transport, nothing came of the rash of Planerlyet designs.

Dimensions (final form) Span Length Wing area	22.4m 6.8m 78.6 m!	73 ft 6 in 22 ft 334 in 846 ff
Weights
Empty	1,440kg	3,1751b
Fuel/oil	200kg	440 Ib
Loaded	2,200kg	4,850 Ib
Performance
Maximum speed	135km/h	84 mph
Cruising speed	115km/h	71.5 mph
Time to climb to 1 ,000 m	25min	(3,281 ft)
Service ceiling approx	2,000m	6,561 ft
Range	850km	528 miles
Take-off run	210m	689ft
Landing speed	60km/h	37 mph

Purpose: To test the guidance system of a cruise missile.

Design Bureau: OKB-155 ofAI Mikoyan.

In late 1947 the Kremlin ordered the develop­ment of a large cruise missile which could be launched (primarily against ships) from the Tu-4. Because of the importance of this pro­ject it was assigned to a joint team formed by OKB No 155 (MiG) and a new semi-political group called SB-1 (Special Bureau Nol). The OKB assigned one of the founders, M I Gure­
vich, as titular head, but the Chief Designer was A Ya Bereznyak who has figured previ­ously on page 29 of this book. Head of SB-1 was S L Beria, son ofthe formidable Politburo member who in 1953 succeeded Stalin. In fact, SB-1 faded from the scene, as it had little to contribute, though it did have P N Kusenko as Chief Designer. Under intense pressure a swept-wing turbojet-engined missile was created, which later went into production as the KS-1 Komet. In early 1949 its guidance sys­tem was tested in an Li-2 (Soviet derivative of
the DC-3), and later in that year a more repre­sentative system was tested in the FK (also called MiG-9L, Laboratoriya). This was too large to be carried aloft by a Tu-4, so it for­mated with the Tu-4 parent aircraft and thence simulated the missile on its flight to the target. Subsequently this aircraft was used to test different cruise-missile guidance systems, assisted by the K-l, a manned ver­sion of the KS-1 missile.

Aircraft FK was a modified MiG-9 twin-jet fighter, the first type of turbojet aircraft to fly in

the Soviet Union. Features included a straight-tapered wing oflaminar profile of9% thickness with large slotted flaps and Frise ailerons, a pressurized cockpit ahead of the wing, a ground-adjustable tailplane mounted part-way up the fin, a nosewheel retracting forwards and main landing gears retracting outwards, and a nose inlet feeding air to two RD-20 turbojets (Soviet copies of the German BMW 003A, each rated at 800kg, l,7641b, thrust) mounted under the wing with jet noz­zles under the trailing edge. The final produc­tion series had an ejection-seat, and the FK was from this batch. The heavy nose arma­ment of three NS-23K guns and all armour
were removed, and the fuselage was extend­ed by splicing in an extra section accommo­dating an unpressurized rear cockpit with a side-hinged canopy for the guidance-system operator. As in the Komet, the missile’s radar dish antenna was mounted above the nose, and a receiver antenna was mounted on the leading edge of each wing. Above the fin was a streamlined container housing the aft-fac­ing transmitter and receiver antennas for the radio-command guidance from the parent aircraft after launch. Once the autopilot had set the correct course the nose radar homed on the parent’s radar signals reflected back from the target. Nearer the target the missile’s
own radar became active, steering by signals received by the leading-edge antennas.

So far as is known, the FK played a valuable role in the development of one of the world’s first turbojet cruise missiles. So did the KSK, a piloted version ofthe missile itself.

Dimensions (FK)

Span 10.0m 32ft9Kin

Length 10.12m 33 ft 2 in

Wing area 18.2m2 195.9ft2

No other data.

K-l, or KSK, manned version of Komet

K-l, KSK

Purpose: To design a long-range supersonic bomber.

Design Bureau: OKB-23 of Vladimir Mikhailovich Myasishchev, Moscow.

In 1955, when the Myasishchev OKB was still striving to develop the huge 3M subsonic bomber, this design bureau was assigned the additional and much more difficult task of creating a strategic bomber able to make dash attacks at supersonic speed. The need for this had been spurred by the threat of the USAF Weapon System 110, which materi­alised as the XB-70. The US bomber was de­signed for Mach 3, but in 1955 this was considered an impossible objective for the Soviet Union. From the outset it was recog­nized that there could be no question of com­peting prototypes from different design teams. Even though the Myasishchev OKB was already heavily loaded with completing development of the huge M-4 strategic bomber and redesigning this into the 3M pro­duction version, this was the chosen design bureau. In partnership with CAHI (TsAGI), wind tunnels were built for Mach 0.93,3.0 and 6.0. The two partners analysed more than 30
possible configurations, initially in the Izdeliye (product) ’30’ family (VM-32, tailless VM-33 and VM-34). The basic requirement was finally agreed to specify a combat radius not less than 3,000km (1,864 miles) and if possible much more, combined with a dash speed (with engine afterburners in use) of Mach 2. This demanded an upgraded aircraft, and the result was the ’50’ series, starting with the M-50. Under chief designer Georgi Nazarov this was quickly accepted, and the initial programme comprised a static-test specimen and two flight articles, comprising one M-50 followed by an M-52. OKB pilots N I Goryainov and A S Lipko flew the M-50 on 27th October 1959. Modified with afterburn­ing inboard engines, it continued testing in late 1960, but was by this time judged to be of limited value, and to be consuming funds needed for ICBMs (intercontinental ballistic missiles) and space projects. The OKB-23 was closed, and its personnel were trans­ferred to V N Chelomey to work on ICBMs and spacecraft. Myasishchev was appointed Director of CAHI. To the protestations of some, the virtually complete M-52 was scrapped, and six later 50-series projects re­
mained on the drawing board. However, for propaganda purposes the M-50 was kept air­worthy and made an impressive but rather smoky flypast at the Aviation Day parade at Moscow Tushino on 9th July 1961, naturally causing intense interest in the West. After being photographed with different paint schemes, and the successive radio callsigns 022, 023,12 and 05, it was parked in the nose – high take-off attitude at Monino.

Apart from the totally different wing, in overall configuration, size and weight the M-50 exactly followed the M-4 and 3M family. Despite this every part was totally new, to the last tyre and hydraulic pump. The wing was of pure delta shape, with CAHI R-II profile of only 3.5 to 3.7 per cent thickness, and with a leading-edge angle of 50° from the root to the inboard engines at 55 per cent semi-span, and 41° 30′ from there to the tip. The tip was cropped to provide mountings for the out­board engines. The leading edge was cam­bered but fixed, while the trailing edge carried rectangular double-slotted flaps and tapered outboard flaperons. At the time this was by far the largest supersonic wing ever flown. Structurally it was based on a
rectangular grid with four transverse spars and seven forged ribs on each side, the skin being formed by forged and machined pan­els. The enormous fuselage was of almost perfect streamline form, which like the wing was skinned with forged and machined pan­els. Only a small two-bay section in the nose formed the pressure cabin for the pilot and navigator seated in tandem downward-eject­ing seats. These were lowered on cables for the crew to be strapped in at ground level, then winching themselves into place. There was neither a fin nor fixed tailplanes. Instead the tail comprised three surfaces, each with a forward-projecting anti-flutter weight and driven by a quadruple power unit in the twin duplex hydraulic systems. A back-up me­chanical control was provided, with rods and levers, but it was expected that this would later be removed. Several possible engines were studied, the finalists being VADo – brynin’s VD-10 and P F Zubts’ 16-17, which was replaced by the 17-18. Construction of the aircraft outpaced both, and in the end the M-50 had to be powered by two Dobrynin VD-7 turbojets on the underwing pylons and two more on the wingtips. As these were tem­porary they were installed in simple nacelles with plain fixed-geometry inlets. Rated at 9,750kg (21,4951b), these were basically the same engines as those of the 3M. Likewise the main landing gears appeared to be simi­lar to those of the previous bomber, but in fact they were totally new. One of the basic design problems was that the weapons bay had to be long enough to carry the llm (36ft) M-61 cruise missile internally. This forced the rear truck, bearing 63 per cent of the weight, to be quite near the tail, reducing the effective mo­ment arm of the tailplanes and threatening to make it impossible for the pilot to rotate the aircraft on take-off. One answer would have been to use enormous tailplanes, greatly in­creasing drag, but a better solution was to do what the OKB had pioneered with the M-4 and 3M and equip the steerable front four – wheel landing gear with a double-extension hydraulic strut. Triggered by the airspeed reaching 300km/h (186mph), this forcibly ro­tated the aircraft 10° nose-up. Another unique feature was that each main gear incorporated a unique steel-shod shoe which, after land­ing, was hydraulically forced down on to the runway, creating a shower of sparks but pro­ducing powerful deceleration, even on snow. For stability on the ground twin-wheel tip pro­tection gears were fitted, retracting forwards immediately inboard of the wingtip engines. All fuel was housed in the fuselage, and yet another unique feature was that to cancel out the powerful change in longitudinal trim caused by the transonic acceleration to su­personic flight fuel was rapidly pumped from Nol tank behind the pressure cabin to No 8 tank in the extreme tail (and pumped back on deceleration to subsonic flight). Over 10 years later the same idea, credited by Myasishchev to L Minkin, was used on Concorde. Flight testing of the M-50 at Zhukovskii was remark­ably rapid, though the aircraft proved stub­bornly subsonic, stopping at Mach 0.99 even in a shallow dive at full power. In early 1960 the M-50 was modified with afterburning VD-7M engines with a maximum rating of 16,000kg (35,275 Ib) on the inboard pylons and derated VD-7B engines rated at 9,500kg (20,944 Ib) on the wingtips. This was consid­ered to offer the best compromise between available thrust, mission radius and propul­sion reliability. The engine installations were redesigned, all four having large secondary cooling airflows served by projecting ram in­lets above the nacelle. The outer engines were mounted on extensions to the wing housing new wingtip landing gears which re­tracted backwards.

The M-52 was under construction from No­vember 1958 and differed in many respects. It was to be powered by four Zubts 17-18 bypass engines each rated at 17,700kg (39,021 Ib). All four were served by efficient variable multi­shock inlets. The inner engines were ‘set at an angle in relation to the chord line’ and the outers were attached to larger pylons with forward sweep. The nose was redesigned and housed navigation/bombing radar, the crew sat side-by-side, a small horizontal sur­face was added on top of the rudder, a re­tractable flight-refuelling probe was added, the interior was rearranged, a remotely con­trolled barbette was fitted in the tail with twin GSh-23 guns, and provision was made to carry one M-61 internally or four Kh-22 cruise missiles scabbed on semi-externally in pairs conforming to the Area Rule. This aircraft was structurally complete in 1960 but when OKB – 23 was closed it was scrapped.

The M-50 was an extraordinary example of an aircraft which physically and financially was on a huge scale yet which had very limit­ed military value. Not least of the remarkable features of this programme was its relative freedom from technical troubles, even though virtually every part was totally new.

Dimensions (M-50 in 1960) Span (over outer engines) Length Wing area 35. 1 m 57.48 m 290.6 m2 115ft2in 188 ft 7 in 3,128ft2 Weights Empty 76,790 kg 169,290 Ib Normal loaded 203,000kg 447,531 Ib Performance Max speed (estimated) 1 ,950 km/h 1,212 mph (Mach 1.84) Cruising spee 800 km/h 497 mph Service ceiling 16,500m 54,134ft Practical range (estimated) 7,400 km 4,598 miles Landing speed (lightweight) 215 km/h 133.6 mph

Purpose: To transport outsize cargoes. Design Bureau: EMZ (Eksperimental’nyi Mashinostroitel’nyi Zavod, experimental engineering works) named for V M Myasishchev.

After directing CAHI (TsAGI) from 1960, Mya­sishchev returned to OKB No 23 in early 1978 in order to study how a 3M strategic bomber might be modified to convey large space launchers and similar payloads. In particular
an aircraft was needed to transport to the Baikonur launch site four kinds of load: the nose of the Energiya launcher; the second portion of Energiya; the Energiya tank; and the Buran spacecraft, with vertical tail and engines removed. These loads typically weighed 40 tonnes (88,183 Ib) and had a diameter of 8m (26ft). Myasishchev had pre­viously calculated that such loads could be flown mounted above a modified 3M bomber. He died on 14th October 1978, the programme being continued by V Fedotov. While design went ahead, three 3MN-II tanker aircraft were taken to SibNIA (the Siberian State Research Instiutute named for

SAChaplygin) and put through a detailed structural audit preparatory to grafting on a new rear fuselage and tail, and mountings for the external payload. The modified aircraft were designated 3M-T. All were rebuilt with zero-life airframes and new engines, but ini­tially without payload attachments. One was static-tested at CAHI while the other two were completed and flown, tne first on 29th April 1981. After a brief flight-test programme they were equipped to carry pick-a-back pay­loads, and in Myasishchev’s honour redesig­nated VM-T Atlant. The first flight with a payload was made by AKucherenko and crew on 6th January 1982. Subsequently the two Atlant aircraft carried more than 150 pay­loads to Baikonur.

The most obvious modification of these air-

craft was that the rear fuselage was replaced by a new structure 7m (23ft) longer and with an upward tilt, carrying a completely new tail. This comprised modified tailplanes and ele­vators with pronounced dihedral carrying in­ward-sloping fins and rudders of almost perfectly rectangular shape, with increased total area and outside the turbulent wake

flight-control and autopilot system. The for­ward fuselage was furnished with work sta­tions for a crew of six. The aircraft were given civilian paint schemes, one being registered RF-01502 and the other being RF-01402 and fitted with a flight-refuelling probe. To support their missions the PKU-50 loading and un­
loading facility was constructed at spacecraft factories, including NPO Energiya at Moscow Khimki, and at the Baikonur Cosmodrome. These incorporated a giant gantry for careful­ly placing the payloads on the carrier aircraft.

Despite the turbulent aerodynamics down­stream of the external payloads, this dramat­

ic reconstruction proved completely success­ful. In the USA a 747 was used to airlift Shuttle Orbiters, but no other aircraft could have car­ried the sections of Energiya.

Purpose: To fly reconnaissance missions at very high altitude.

Design Bureau: EMZ named for V M Myasishchev.

Though not an experimental aircraft, the M-17 qualifies for this book because of its nature, its ancestry, and the fact that it was the basis for the M-55 research aircraft. The concept of manned reconnaissance aircraft penetrating hostile airspace at extreme altitude was com­
mon in the Second World War, and in the Cold War reached a flash point on 1st May 1960 when the U-2 ofF G Powers, a CIA pilot, was shot down over Sverdlovsk. One of the American alternatives studied and then actu­ally used was unmanned balloons launched in such a way that prevailing winds would carry them across Soviet territory. They could change altitude, and could carry not only re­connaissance systems but also explosive charges. This threat could have been serious,

and the PVO (air defence forces) found it dif­ficult to counter. Though still at CAHI, Mya­sishchev was made head of a secret EMZ tasked with Subject 34, a high-altitude bal­loon destroyer. Called Chaika (Gull) from its inverted-gull wing, it was to be powered by a single Kolesov RD-36-52 turbojet of 12,000kg (26,4551b) thrust. To reduce jetpipe length the tail was carried on twin booms. In the nose was to be radar and the highly pressur­ized cockpit, while between the engine inlet ducts was a remotely controlled turret hous­ing a twin-barrel GSh-23 gun. Secretly built at Kumertau helicopter plant in Bashkirya, the Chaika was first flown in December 1978 by K V Chernobrovkin. He had been engaged in taxi tests, and had not meant to take off but in a snowstorm became airborne to avoid hit­ting the wall of snow on the right side of the runway. In zero visibility he hit a hillside. The programme was relocated at Smolensk, where the second aircraft was constructed to a modified design, designated M-l 7. The first, No 17401, was first flown by E VChePtsov at Zhukovskii on 26th May 1982. It achieved a lift/drag ratio of 30, and between March and May 1990 set 25 international speed/climb/ height records. In 1992 it investigated the ‘hole’ in the ozone layer over the Antarctic. The second M-17, No 17103, was equipped with a different suite of sensors. From the M – 17 was derived the M-55 Geofizka described next.

The M-17 had an all-metal stressed-skin structure designed to the low factor of 2. The remarkable wing had an aerofoil of P-173-9 profile and aspect ratio of 11.9, and on the ground it sagged to an anhedral of-2° 30′. The original wing had 16 sections of Fowler flap and short ailerons at the tips, but it was re­designed to have a kinked trailing edge with simplified flaps and longer-span two-part ailerons. Large areas of wing and tail were skinned with honeycomb panels. Flight con­trols were manually operated, in conjunction with a PK-17 autopilot. The tricycle landing gears retracted hydraulically, the 210kg/cm2 (3,000 lb/in2) system also operating other ser-

vices including three airbrakes above each wing. The engine was an RD-36-51V, with a take-off rating of 12,000kg (26,455 Ib) and nominal thrust of half this value. Cruise thrust at 21,000m (68,898ft) was 600kg (1,32315). T – 8V kerosene was housed in two 2,650 litre main tanks, two 1,550 litre reserve tanks and a 1,600 litre collector tank, a total of 10,000 litres (2,200 Imperial gallons). The pressur­ized and air-conditioned cockpit housed a
very fully equipped K-36L seat, and among other equipment the pilot wore a VKK-6D suit and VK-3M ventilated suit, and a ZSh-3M pro­tective helmet and KM-32 mask overlain by a GSh-6A pressurized helmet. Avionics were extremely comprehensive.

The M-17 fulfilled all its design objectives. The successive changes in both mission and aircraft design were caused solely by political factors.

Purpose: To study the ozone layer and perform many other surveillance tasks. Design Bureau: EMZ named for V M Myasishchev, General Designer V K Novikov.

The M-l 7 proved so successful in its basically politico-military role that it was decided in 1985 to produce a derived aircraft specifically tailored to Earth environmental studies. The first M-55, No 01552, was first flown on 16th August 1988, the pilot being Nil Merited Pilot Eduard V Chel’tsov who had carried out the initial testing ofthe M-1 7. Three further exam­ples were built, Nos 55203/4/5. Further single – seaters, plus the M-55UTS dual trainer, the Geofizka-2 two-seat research aircraft and other derived versions, have been shelved through lack of funds.

Structurally the M-55 was designed to a load factor increased from 2 to 5. This result­ed in a new wing which instead of having left/right panels joined on the centre line has inner and outer panels joined to a centre sec­tion. Aspect ratio is reduced to 10.7, and aero­dynamically the wing retains the P-173-9 profile but has redesigned flaps, ailerons and upper-surface airbrakes. The horizontal tail is modified, with full-span elevator tabs and square tips. The fuel capacity is increased to

10,375 litres (2,282 Imperial gallons), and range/endurance was further increased by changing to a pair of P A Solov’yov D-30-10V turbofans each rated at 9,500kg (20,944 Ib) take-off thrust, and with a combined cruise thrust at 21km (68,898ft) of 670kg (l,4771b). Apart from the landing gear the aircraft was almost totally redesigned, the front of the na­celle being much deeper and more capa­cious, the engine bays being lengthened, and the flight controls being operated by a dual­channel digital system with manual rever­sion. In standard form the M-55 carries a payload of up to 1.5 tonnes (3,307 Ib), typical­ly comprising a Radius scanning radiometer with swath width of 20km (12.4 miles), a
choice ofIR linescanners with swath width of 25km (15.5 miles), an Argos optical scanner with swath width of 28km (17.4 miles), an A-84 optical camera with swath width of 120km (74.6 miles) and a choice of SLARs (sideways-looking airborne radars) with max­imum swath width of 50km (starting at 30km and extending to 80km) on each side. Cover­age of 100,000km2 (38,610 square miles) per hour is matched to an instrumentation trans­mission rate of 16 Mbits per second.

The EMZ have created a versatile research and geophysical aircraft which is being pro­moted for such varied tasks as search/rescue, mapping, ozone studies, hailstorm preven­tion and agricultural monitoring.

Dimensions Span 37.46m 122 ft 10% in Length 22.867 m 75 ft M in Wing area 131.6m2 1,417ft2 Weights Empty 13,995kg 30,853 Ib Maximum take offweight 23,800kg 52,469 Ib Performance Maximum speed at 5 km (16,404 ft) 332 km/h 206 mph at 20 km (65,61 7 ft) rising to 750 km/h 466 mph Practical ceiling 2 1,850m in 35 min (71,686ft) Endurance at practical ceiling 2hrs 14 min at a cruise height of 1 7 km 6 hrs 30 min (55,774ft) Max range on direct flight 4,965km 3,085 miles Take-off/landing Similar to M-17.

Purpose: To exceed Mach 1 and possibly serve as the basis for a fighter.

Design Bureau: P O Sukhoi, Moscow.

Note: this aircraft was not related to later aircraft with the same designation.

In late 1947 the Council of Ministers issued a plan for 1948-49 calling for the construction of new experimental aircraft. One type was to research high-subsonic, transonic and low supersonic speeds, and also if possible pro­vide the basis for the design of a supersonic tactical fighter. Contracts were issued to Yakovlev (Type 1000) and Sukhoi (Aircraft R). In each case funds were provided for one flight article and one static test specimen, and Sukhoi’s design proceeded rapidly. From the outset provision was made for two heavy can­non, and in 1949 the WS designation Su-17 was issued. As early as July 1949 the flight ar­ticle was taken to LIl-MAP at Zhukovskii, where the assigned pilot, Sergei Anokhin, car­ried out increasingly fast taxi tests. Just as he was about to make the first flight the Su-15 radar-equipped interceptor suffered violent flutter and crashed, Anokhin ejecting. Rather precipitately, CAHI (TsAGI) blamed Sukhoi, and moreover claimed that the wing of Air­craft R was also torsionally weak and would flutter at high airspeeds. CAHI therefore re­fused to issue flight clearance for this aircraft. In turn this led Stalin to order that Sukhoi’s OKB should be liquidated on 1st November 1949. It was reopened in 1953 after Stalin’s death.

This outstanding design was made possi­ble by the rapid development of the powerful TR-3 (later called AL-5) afterburning axial tur­bojet by A M Lyul’ka, qualified in January 1950 at4,600kg (10,141 Ib), with a dry rating of 4 tonnes (8,8181b). Had the Su-17 continued it would certainly have later flown with more powerful Lyul’ka engines. The propulsion system was ‘straight through’ from the plain nose inlet, which immediately divided to pass each side of the cockpit, to the tail. Amid­
ships, at Frames 15/15A and 20/20A, the main wing spars passed through at mid-level. The wing had CAHI (TsAGI)-9030 profile at the root, changing to symmetric SR-3-12s at the tip, the!4-chord sweep being 50°. Above each wing were two full-chord fences plus another from the leading edge to the aileron. Three tracks carried each of the Fowler-type flaps. High on the large vertical tail was mounted the fixed tailplane, again with 50° A-chord sweep and ground adjustable over the range ± 1.5°. The port aileron and starboard elevator had tabs, and the rudder had a section of ‘knife’ (thin strip behind the trailing edge). This aircraft pioneered Soviet use of hydrauli­cally boosted flight controls, on all axes. All units of the landing gear had levered suspen­sion, using high-pressure shock absorbers pi­oneered on the Su-15, and retracted into the fuselage. The nose unit had a 530 x 230mm tyre and retracted to the rear, while each main unit had an 800 x 225mm tyre and pneu­matic plate brake and retracted forwards about a skewed axis under the wing root, to be covered by a large door. The ventral bulge under the tail had a steel underside and made provision for housing a cruciform braking parachute. On each side of the rear fuselage was a door-type airbrake, opened to 60°, which like the flaps, landing gear and flight controls, was operated by a hydraulic system at what was then a new high pressure of 211kg/cm2 (207-MPa, 3,000lb/in2). The cock­pit was pressurized, maintaining 0.65kg/cm2 (9.2 lb/in2) up to 7km (22,966ft) and holding a constant dp of 0.3kg/cm2 (4.3 lb/in2) above that level. Like several previous Soviet air­craft, the pilot’s ejection-seat was mounted in a nose section designed to separate from the fuselage in an emergency. The planar joint, sealed by an inflatable ring, sloped forward to avoid the nose-gear, and it could be broken by firing a cordite charge at the bottom joint, allowing the nose to pivot and separate from the two upper connections. Separation was triggered automatically if vertical accelera­
tion reached ± 18 g, or under pilot commcind. The separated nose streamed a drogue which after a delay extracted the main ribbon parachute. The pilot could then eject, experi­encing a maximum of 5 g. The pilot could also eject normally, from the intact aircraft, but only after jettisoning the sideways-hinged canopy. A total of 1,219 litres (268 Imperial gallons) of fuel was housed in the fuselage, there being one metal and two bladder tanks behind the cockpit and three metal tanks (one a toroidal hollow ring) around the jet- pipe. Provision was made for a jettisonable 300 litre (66 Imperial gallon) tank to be scabbed under each wing, and for two N-37 guns, each with 40 rounds, to be mounted in the fuselage. The avionics were comprehen­sive, including vhf, radio compass, an IFF transponder and precision radio altimeter.

There is no reason to doubt that this aircraft would have been most valuable, and prevent­ing it from flying appears in retrospect to have been a serious error. The Soviet Union suf­fered from its thoughtless precipitate actions.

Dimensions Span Length Wing area	9.6m 15.253m 27.5 rrf	31 ft 6 in 50 ft ‘A in 296 ft2
Weights
Empty	6,240kg	13,757 Ib
Loaded	7,390kg	16,292 Ib
Performance (estimated)
Max speed, at sea level	l,252km/h	778 mph (Mach 1.022)
at 10 km (32,808 ft)	1,152 km/h	716 mph (Mach 1.08)
Time to climb to 10km	3.5 min	(32,808ft)
Service ceiling	15.5km	50,853 ft
Range (internal fuel at 10 km cruising at 830	km/h, 516 mph)
	550 km	342 miles
Take-off run	450m	1,476ft
Landing speed/	194 km/h	120.5 mph
run	660m	2,165ft

Su-17, R

Left: Two views of Su-17, R.

Above: Looking back at the Su-17 with jettisonable cockpit removed.

For interest, drawings are reproduced here of various projects which stemmed from the RSR. The first shows the way CAHI (TsAGI) wanted it. The purist aerodynamicists in that establishment were convinced that this su­personic-cruise aircraft ought to have true su­personic wings, with sharp edges and a trapezoidal (parallel double wedge) profile instead of a traditional curved aerofoil. As this would have meant a very long take-off run they proposed to add substantial wings out­board of the engines, giving a span of 14.5m (47ft 6%in), requiring total redesign and a dra­matically inferior aircraft. The next drawing shows the awesome A-57, proposed in 1957 by R L Bartini, who featured on previous pages. There were several versions of this and the considerably smaller Ye-57. The A-57 shown would have been powered by five Kuznetsov NK-10 engines, each of 25,000kg (55,115 Ib) thrust. This 320 tonne (705,467 Ib) vehicle, with a length of 69.5m (228ft) and wing area of 755m2 (8,127ft2), was to have been water-based for operational flexibility and to avoid having to use vulnerable airfields (though it also had skids for airfield landings if necessary). It would have carried a 244N thermonuclear bomb internally, as well as a 2RS (later RSR) carried pick-a-back to the tar­get at 2,500km/h (l,553mph, Mach 2.35) to serve as an accompanying reconnaissance aircraft. Together they could cover targets within a radius of 5,000km (3,107 miles), the Tsybin 2RS reconnaissance vehicle using its fuel only on the return flight. The final draw­ing shows the Tsybin RGSP, also dating from 1957. This too would have been water-based, with a planing bottom, engines moved above the wings to avoid the spray (minimised by the down-angled water fins), and with the ex­ternal tanks serving as wingtip buoyancy bod­ies. This version was not equipped for airfield landings.

Purpose: To build an improved fighter armed with APK-4 guns.

Design Bureau: Brigade led by Viktor Nikolayevich Chernyshov inAGOS (Department of Aeroplane and Hydroplane Construction), whose Chief Constructor was A N Tupolev.

Towards the end of the 1930s there was great activity in the still chaotic aircraft industry of the embryonic Soviet Union. Part of this ef­fort was concerned with making use of the large-calibre recoilless guns devised by L V Kurchevskii. These had various designations
but the most common was APK (Avto – matichyeskaya Pushka Kurchevskogo, auto­matic cannon Kurchevskii). Such guns were invented by Cdr Cleland Davis, ofthe US Navy, and developed in England from 1915. The idea was that, if the recoil of the projectile could be balanced by a blast of gas and pos­sibly an inert mass fired to the rear, then air­craft could use lightly made weapons of large calibres. Russian copies were produced by Professor B S Stechkin in 1922-26, and in 1930 Leonid Vasil’yevich Kurchevskii restarted this work and developed a range of weapons of different calibres. Of these the most immedi-

ately important was the APK-4, with a calibre of 76.2mm (Sin). Together with the Grig – orovich Z (later I-Z) described earlier, the ANT-23 was the first aircraft specially de­signed to use these guns. The AGOS design­ers had the idea that, instead of just hanging the guns under the wings, they could be put inside strong tubes which could then attach the tail to the wing. This enabled the central nacelle to have an engine at each end, giving outstanding flight performance. Design began in June 1930, and the first flight was made by Ivan Frolovich Kozlov on 29th August 1931. On 21st March 1932 he was

undertaking firing trials at about 1,000m (3,280ft) when the diffuser section at the rear of the left gun exploded. This severed the tail controls in that boom, but he managed to make a normal landing, the boom collapsing during the landing run (he received the Order of the Red Star). The fault was soon correct­ed, and from autumn 1931 a second proto­type (called a doobler), the ANT-236/s, was built. This received service designation I-12, and was also named Baumanskii Komsomo – lets after the revolutionary who until his death in 1905 had worked next to the AGOS site. It incorporated various minor improvements, one of which was to arrange for the pilot in emergency to detonate a charge which sev­ered the drive shaft to the rear propeller prior to baling out. Work was halted during the in­vestigation into the accident to the first air­craft, and by 1933 the I-12 was overtaken by the Grigorovich IP family and the DIP, ANT-29. Work on it was stopped on 1st January 1934.

Structurally the ANT-23 followed Tupolev tradition in that it was a cantilever monoplane made entirely ofaluminium alloy, but it broke new ground in that corrugated sheet was not used except on the fin and rudder. Instead, the central nacelle had smooth skin, and the wings were skinned in sheets cut to a uniform
width of 150mm (Gin), wrapped round the leading edge. The edge of each strip was rolled to have a channel section, so that the complete wing appeared to have a skin with widely spaced corrugations. In usual Tupolev fashion, the aileron chord extended behind the trailing edge ofthe wing. The nacelle was welded from KhMA steel tube, with much of the light-alloy skin being in the form of de­tachable panels. At each end was an import­ed 480hp Gnome-Rhone GR9K (licence-built Bristol Jupiter) in a cowling with helmets over the cylinders. Above each wing was attached a precision-made tube of high-strength steel formed by screwing together three sections each machined to an internal diameter of 170mm (6%in). Wall thickness varied from 1 to 3mm. Over the wing the tube was faired in by thin aluminium sheet, and at the tail end was a gas diffuser. Above this was a shallow platform to which was attached the tailplane, carrying the strut-braced fin in the centre. Tall sprung tailskids were attached under each tube, and originally the rubber-sprung main landing gears had spats, though these were later omitted. Inside each tail boom was in­stalled the 76.2mm APK-4, with the front of the barrel projecting. Soon the engines were replaced by the 570hp version made under
licence in the Soviet Union as the M-22, and the helmets were incorporated into ring cowls. Another modification was to replace the ver­tical tail by a redesigned structure with the same kind of skin as the rest of the aircraft.

When work began it was thought that this aircraft might be a world-beater. It was soon evident that the performance was well short of expectations, partly because ofthe fact that the rear propeller worked in the slipstream of that in front. Perhaps the greatest shortcom­ing of this aircraft was the fact that the am­munition supply for each gun was limited to two rounds.

Dimensions Span Length Wing area 15.67m 9.52m 33.0 m2 51 ft 5 in 31 ft 2 in 355 tf Weights Empty 1,818kg 4,008 Ib Loaded 2,405 kg 5,302 Ib Performance Max speed at 5 km (16,400 ft) 318 km/h 198 mph Time to climb to 5 km 7.7 min (16,400ft) Service ceiling 9,320 m 30,580ft Range 405km 252 miles Landing speed l00knVh 62 mph

Two views of ANT-23 after modification.

Purpose: A heavy fighter with large-calibre recoilless guns.

Design Bureau: KOSOS-CAHI (department of experimental aeroplane construction, central aero-hydrodynamics institute), Chief Constructor A N Tupolev.

This large fighter was a natural successor to the ANT-21 MI-3 (MI = multi-seat fighter) or­dered in January 1932 and flown in May 1933. Whereas that aircraft had had conventional armament, the ANT-29 or DIP (Dvukhmestnyi Istrebitel’ Pushechnyi, two-seat cannon [armed] fighter) was designed around two of the largest available calibre of APK recoilless guns (see preceding story). Funds for a single prototype were made available by the WS in September 1932. Tupolev entrusted the de­sign to his first deputy P O Sukhoi. Normally the aircraft would have flown in about a year, but priority was given to the ANT-40 fast bomber (which flew in 1934 as the SB), and the ANT-2 9 was not completed until February 1935. Flight testing was started by S A Korzin – shchikov, who reported that the flight con­trols, especially the ailerons and rudder, were unacceptably ineffective. This prototype was returned to CAHI’s ZOK (factory for prototype construction) for rectification, the main task being to re-skin the control surfaces. Testing resumed in late 1935, but by this time the ANT-46 (DI-8) was flying. The ANT-29 be­longed to the previous generation, and it was abandoned in March 1936.

Like its predecessor, the ANT-21, the ANT – 29 was an aerodynamically clean monoplane powered by two liquid-cooled engines. The wings were aerodynamically similar but to­tally different structurally, and the engines likewise were quite new. They were two of the first 760hp Hispano-Suiza 12Ybrs 12-cylin­der engines to be imported into the Soviet Union. Later this engine was developed by VYaKlimov into the VK-103 and VK-105, of which over 129,000 were constructed. In this aircraft they drove imported French Chau – viere three-blade variable-pitch propellers of 3.5m (138in) diameter. Carburettor air en­tered through a small inlet under the wing leading edge, and the radiator was in a shut­ter-controlled duct directly under the engine. The wing had a modern structure with two plate spars, made as a 3m (9ft 1 0in) horizon­tal centre section and 5.9m (19ft 4in) outer panels with taper and dihedral. Like the rest of the airframe the outer wing skins were smooth. In this Sukhoi broke new ground, previous ‘ANT’ aircraft having had corrugated metal skins showing that they originated in Junkers technology of the early 1920s. The short fuselage was of tall oval section and

Dimensions
Span	19.19m	62 ft min
Length overall	11.65m	38ft23/4in
(excluding guns)	ll. lm	36 ft 5 in
Wing area	56.88 nf	612 ft2

Weights Empty Fuel/oil Loaded (normal) (maximum)	3,876kg 720+80 kg 4,960kg 5,300kg	8,545Ib I, 587+176 Ib 10,935 Ib II, 6841b
Performance
Max speed at sea level,	296km/h	184 mph
at 4 km (13, 123 ft)	352 km/h	219 mph
Time to climb 3 km (9,842 ft) 5.6 min
5 km (16,400 ft) No other reliable data.	9.6 min

Two views of ANT-29.

seated the pilot in the nose under a rearward – sliding canopy and a backseater over the trail­ing edge under a forward-sliding canopy (as in early versions of the SB). The backseater would have worked radio had it been fitted, but his main task was to check the automatic reloading of the guns and clear stoppages. The wings were fitted with large two-part ailerons and split flaps, while the tail carried the wire-braced tailplane high up the fin, the elevators and rudder having large Flettner (servo) tabs. Like the ANT-21 and SB, the main landing gears had single shock-struts with a fork carrying the axle for a braked wheel with a 900 x 280mm tyre which, after retraction to the rear, partially projected to minimise damage in a wheels-up landing. At the rear was a large tailskid. Main-gear re­traction, like flap operation, was hydraulic. The primary armament comprised two APK – 8 recoilless guns, also known as DRP (Dy – namo-Reaktivnaya Pushka), mounted one above the other. The feed was via two chutes on opposite sides of the fuselage. Each gun
had an unrifled barrel about 4m (13ft lin) long, with a calibre of 102mm (4in). The firing chamber was connected at the rear to a re­coil tube terminating in the recoil-cancelling divergent rear nozzle, extended a safe dis­tance behind the rudder, through which pro­pellant gas blasted when each round was fired. Sighting was done with an optical sight in a prominent fairing ahead of the wind­screen, and could be assisted by firing tracer from two 7.62mm ShKAS machine guns in the wing roots (these are shown in Shavrov’s drawings, but unlike the main armament they do not appear ever to have been installed). It was intended also to fit a pivot-mounted ShKAS in the rear cockpit. There was no pro­vision for a bomb load. Arguments over ar­mament continued, but no attempt was made to test the ANT-29 with the alternative forward-firing armament ofa20mm ShVAK in each wing root.

By the time it was on test this was no longer an important aircraft, and (for reasons not recorded) it failed NIl-WS testing.

Purpose: An improved heavy fighter with large-calibre recoilless guns.

Design Bureau: KOSOS-CAHI, chief constructor A N Tupolev, who assigned this aircraft to A A Arkhangel’ skii.

This aircraft was a derivative of the SB (ANT-40) fast bomber. The single prototype was ordered in November 1934, on condition that the SB (the first prototype of which had flown a month previously) had priority and would not }n any way be delayed. The DI-8 was created quickly and was flown by Yu A Alekseyev on 1 st August (also reported as 9th August) 1935. Factory testing was con­tinued to June 1936, but the ‘liquidation’ of

Kurchevskii’s gun bureau and the arrest for treason and spying of Tupolev halted the pro­gramme.

Until recently little was known about the ANT-46, and only one photograph had been discovered. This did not show the nose clear­ly, and published accounts stated that the ANT-46 was based on the SB but had a metal­skinned nose containing machine guns. It is now known that it had a glazed nose identi­cal to that of the bomber. Instead of being a two-seat aircraft it also had a navigator/ bomb-aimer in the nose, and an internal bomb bay (for example, for eight FAB-100 bombs) with bomb doors. The interesting feature was that incorporated in each wing
outboard of the fuel tanks, between the split flaps and the ailerons, were single DRP (APK – 11) recoilless guns, each fed by an automati­cally indexed supply of 45mm (IXin) ammunition, the rear blast tubes projecting behind the trailing edge. Like the first SB the fin and rudder had a squared-off top, and the engines were not as previously thought GR14s but, as on the first SB, nine-cylinder Wright Cyclones of 710hp, driving Hamilton two-blade propellers. Like the ANT-29, this aircraft carried CAHI titles and the ANT num­ber 46 on the tail.

This aircraft fulfilled expectations, but was considered an outdated concept.

Dimensions Span 20.33 m 66 ft 8% in Length (excluding nose gun) 12.1 7 m 39 й 1 13/1 in Wing area 55.7m2 600 a! Weights Empty 3,487kg 7,687 Ib Maximum loaded 5,553 kg 12,242 Ib Performance Maximum speed at 4,250m (13,944 ft) 388 km/h 241 mph Time to climb 3 km (9,842 ft) 6.8 min Service ceiling 8,570 m 28,120ft Range 1,780km 1,1 00 miles

ANT-46