Category Soviet x-plenes

Purpose: To create a superior tactical attack bomber.

Design Bureau: P O Sukhoi, Moscow.

As noted in the story of the S-22I (S-32), publi­cation of the formidable requirements for the USAF’s TFX programme spurred a response by the USSR. These requirements called for long range with a heavy bombload and the ability to make a blind first-pass attack at su­personic speed at low level ‘under the radar’. There was obvious need to replace the IL-28 and Yak-28, and the task appeared to call for either the use of a battery of special lift en­gines or a VG (variable-geometry, ie variable- sweep) wing. Sukhoi OKB was entrusted with this important task, and took a ‘belt and braces’ approach. To get something flying quickly it decided to put VG wings on the outstanding Su-7B, resulting in the S-22I described previ­ously. For the longer term it launched devel­opment ofa new aircraft, the S-6. This was first drawn in 1963, and it was to have a fixed swept wing, two Metskvarichvili R-21F-300 en­gines each with a wet afterburning rating of 7,200kg (15,873 Ib), pilot and navigator seated in tandem, and the Puma navigation and weapon-delivery system. Five hardpoints were to carry a load of 3 tonnes (6,614 Ib), take-off weight being 20 tonnes (44,090Ib), and maximum speed was to be l,400km/h (870mph) at very low level and 2,500km/h (l,553mph, Mach 2.35) at high altitude. Short­take-off capability was to be provided by two large take-off rockets. As a cover, and to assist
in obtaining funds more quickly, the S-6 was redesignated T-58M to look like a member of that interceptor family, but in 1964 it was ter­minated. This was partly because of in – tractible problems with the engine (see MiG Ye-8), and partly because of the good progress with the T-58VD (see previous). In early 1965 the S-6 was replaced by the T-6, later written T6. This was a significantly larger and more powerful aircraft, even surpassing the F-lll, which was in production by then. After rollout it was given the callsign Red 61 and first flown by the chief test pilot, Vladimir S Ilyushin, on 2nd July 1967. It was fitted with a battery of lift jets, as in the T-58VD, and it was immediately found that (as before) these caused aerody­namic and control difficulties. In 1968 the R-27 main engines were removed and the com­plete rear fuselage and powerplant systems modified to take the Lyul’ka AL-21F engine, with a maximum afterburning rating of 11,200kg (24,691 Ib). To improve directional stability the wingtips were tilted sharply down in TSR.2 fashion, the anhedral being 72°. Large strakes were added on each side of the rear fuselage, and the airbrakes deleted. To meet the needs of radar designers the nose radome was made shorter, with no significant effect on drag, and over the years numerous flush antennas and fairings appeared. Even after the decision was taken to change the design to have high-aspect-ratio ‘ swing wing s’ the T6-1 continued testing systems and equipment. In 1974, having made over 320 test flights, it was retired to the WS Museum at Monino.

In fact, the design ofthe T6-1 had been even more strongly influenced by the British TSR.2, with a fixed-geometry delta wing of short span and large area and fitted with powerful blown flaps. Before the first aircraft, the T6-1, was built the wing was modified with the leading – edge angle reduced from 60° to 45° outboard of the flaps, ahead of the conventional ailerons. As originally built, the large fuselage housed two Khachaturov (Tumanskii KB) R – 27F2-300 engines each with a wet afterburn­ing rating of 9,690kg (21,3651b), fed by sharp-edged rectangular side inlets with an inner wall variable in angle and throat area. Downstream of the inlets the fuselage had a broad box-like form able to generate a con­siderable fraction of the required lift at super­sonic speed at low level. Ahead of the inlets was an oval-section forward fuselage housing two K-36D seats side-by-side, as in the F-lll, an arrangement which was considered an ad­vantage in a first-pass attack and also to assist conversion training in a dual version. There were left and right canopies each hinged up­ward from the broad spine downstream. The width of the cockpit left enough space be­tween the engine ducts for a considerable fuel tankage as well as two pairs of RD-36-35 lift jets, installed in a single row as in the T-58VD. No attempt was made to bleed any engines to provide air for reaction-jet controls, because the T6-1 was not designed to be airborne at low airspeeds. The one-piece tailplanes were in fact tailerons, driven individually by KAU – 125 power units to provide control in roll as well as pitch. For operation from unpaved strips the levered-suspension main landing gears had twin wheels with tyres 900 x 230mm, retracting forwards into bays under the air ducts, while the steerable nose gear again had twin wheels, 600 x 200mm, with mudguards, retracting to the rear. At the ex­treme tail an airbrake was provided on each side, requiring a cutaway inboard trailing edge to the tailplanes, and between the jet nozzles under the rudder was a cruciform braking parachute. For the first time the avion­ics were regarded as a PNK, a totally integrat­ed navigation and attack ‘complex’, and the T6-1 played a major role in developing this. It was fitted with four wing pylons with inter­faces for a wide range of stores, as well as two hardpoints inboard of the main-gear bays, the maximum bombload being 5 tonnes (ll,0201b). The production Su-24 has eight hardpoints for loads up to 8 tonnes (17,637 Ib).

The T6-1 was a stepping-stone to a family of powerful and formidable aircraft which in 2000 are still in service with Russia and Ukraine. Unquestionably, the liftjets were not worth having.

Purpose: To create a superior heavy fighter. Design Bureau: P O Sukhoi, Moscow.

In 1969 the IA-PVO, the manned interceptor defence force, issued a requirement for a to­tally new heavy interceptor. This was needed to replace the Tu-128, Yak-28P and Su-15 in defending the USSR against various cruise missiles, as well as the F-l 11 and other new Western fighters and tactical aircraft. A spe­cific requirement was to combine long-range standoff-kill capability with performance and combat agility superior in a close dogfight to any Western aircraft. The formal competition was opened in 1971. Though Mikoyan and Yakovlev were invited to participate, all the running was made by Sukhoi OKB, which was eager to move on from the T-4 and get a new production aircraft. With Sukhoi himself semi-retired, Yevgenii Ivanov was appointed chief designer, with Oleg Samolovich deputy. Sukhoi’s two rival OKBs made proposals, but did not receive contracts to construct proto­type aircraft to meet this requirement (though the standoff-kill demand was also addressed by the later M1G-25P variants and MiG-31).

Sukhoi submitted two alternative proposals. Both were broadly conventional single-seat twin-engined aircraft with ‘ogival Gothic’ wings (almost delta-shape but with a double­curved leading edge) and horizontal tails, the only new feature being twin vertical tails. One had side air inlets with horizontal ramps, while the other proposal had a fuselage blended into a wing mounted underneath and two complete propulsion systems mounted under the wing. A detail was that both had outstanding pilot view with a drooped nose and bulged canopy. As the wing was more akin to a delta than to a swept wing the project was given the designation T-l 0 in the T series (see T-3). The competitive design review was won by Sukhoi in May 1972. CAHI (TsAGI) had tunnel-tested T-10 models from 1969, and the work built up each year until 1974, demanding more tunnel test­ing than any previous Soviet aircraft except the Tu-144. It was the unconventional config­uration that was chosen, with the fuselage tapering to nothing above the wing and being replaced by large engine gondolas under­neath. Drawings for the first prototype, the

T10-1, were issued in 1975. Construction was handled by the OKB factory, except for wing and tail surfaces which were made at the OKB’s associated huge production facility named for Cosmonaut Yuri Gagarin at Komsomolsk-na-Amur in Siberia. Vladimir Ilyushin began a successful flight-test pro­gramme on 20th May 1977. Investigation of basic handling, including high-AOA (angle of attack) flight, was completed in 38 flights by late January 1978. Four wing fences were added, together with anti-flutter rods on the fins and tailplanes. Many further flights ex­plored the FEW (fly-by-wire) flight controls and, after fitting no fewer than seven hard – points where pylons could be attached, the weapons control system. Red 10 was finally put on display in the Monino Museum. T10-2 began flying at the beginning of 1978, but a software error led to unexplored resonance which caused inflight breakup, killing Evgeny Solov’yov. By 1978 the OKB was busy with T10-3, the first prototype fitted with the defin­itive engine, and this was flown by Ilyushin on 23rd August 1979. In 1982 T10-3 was flown by OKB pilot Nikolai Sadovnikov from a simulated

aircraft-carrier ramp, and it later made hook – equipped simulated carrier landings. T10-4, first flown by Ilyushin on 31st October 1979, tested the new engines and avionics. So great was the need to test avionics that the Komso – molsk factory was contracted to build five further prototypes. These were designated T10-5, -6, -9, -10 and -11 (T10-7 and -8 were significantly modified). These additional pro­totypes were generally similar to T10-3, apart from the fact that the fins were canted out­wards. The T10-5 flew in June 1980, and the remainder were all on flight test by autumn 1982. Pavel Sukhoi died on 15th September 1975, and was succeeded as General Con­structor by Mikhail P Simonov. Soon after he took over, the first detailed information on the McDonnell Douglas F-15 became available. Computer simulations found that the T-10 did not meet the requirement that it should be demonstrably superior to the USAF aircraft. Simonov ordered what amounted to a fresh start, telling the author ‘We kept the wheels and ejection-seat’. Designated T-10S, from Seriynii, production, the new fighter can only be described as brilliant. Ever since the first pre-series example, the T10-17, was flown by Ilyushin on 20th April 1981 it has been the yardstick against which other fighters are judged. An enormous effort was made by Nil using T10-17 and T10-22 to clear the re­designed aircraft for production. The first true series aircraft, designated Su-27, was flown at Komsomolsk in November 1982.

The T-10 wing had 0° dihedral, and a sym­metric profile with a ruling thickness/chord ratio of 3.5 per cent, rising to 5 per cent at the root. The leading edge was fixed. It left the fuselage with a sharp radius and with a sweep angle of 79°, curving round to 41° over the outer panels and then curving back to Kiichemann tips. The main torsion box had three spars and one-piece machined skins. Most of the interior was pressurized and formed an integral tank, while high-strength ribs carried armament suspension points. The oval-section fuselage forward section was designed to accommodate the intended large radar, followed by the cockpit with a sliding canopy. Behind this came an equip­ment bay, followed by a humpbacked ‘forecastle tank’ and then a broad wing cen­tre-section tank which could be considered as part of both the wing and fuselage. A fur­ther tank was placed in the keel beam be­tween the engines. The latter were of the Lyul’ka AL-21F-3 type, each with an after­burning rating of 11,200kg (24,691 Ib). Each was placed in a large nacelle or gondola under the wing, tilted outward because of the inboard wing’s sharp taper in thickness. Each engine air duct was fed by a wedge inlet be­hind the leading edge, standing well away under the wing’s underskin to avoid swallow­
ing boundary-layer air. Each inlet contained a variable upper ramp, with auxiliary side inlets for use on take-off, and a curved lower por­tion. The large engine gondolas provided strong bulkheads on which were mounted the two vertical fins and the tailplanes. The AL-21 had its accessories mounted on top, and the massive structure and fins immedi­ately above made access difficult. From the third aircraft the engine was the Lyul’ka AL-31F, which had been specially designed for this aircraft. It had an afterburning rating of 12,500kg (27,557 Ib), and offered several other advantages, one being that it was half a tonne (1,100 Ib) lighter than the AL-21F. It had its accessories partly underneath and partly far forward on top, and the vertical tails were moved outboard away from the engine com­partments. The main landing gears had large (1,030 x 350mm) tyres on single legs and re­tracted forwards, rotating the wheel through 90° to lie flat in the root of the wing in a bay closed by side doors and large front doors which served as airbrakes. The tall nose gear had a single unbraked wheel with a 680 x 260mm tyre. It retracted backwards, and was fitted with an all-round mudguard to protect the engine inlets. The main-wheel wells re­quired a thick inboard section of the wing ad­jacent to the engine gondolas, and this was carried to the rear to provide strong beams to which the tailplanes (and in the redesigned aircraft the fins) were pivoted. The T-10 flight controls comprised conventional ailerons, two rudders and the independently con­trolled tailplanes. All these surfaces were dri­ven by power units each served by both the completely separated 210kg/cm2 (2,987 lb/in2) hydraulic systems. These systems also drove the plain flaps, landing gears (with indepen­dent airbrake actuation), nosewheel steering,
engine inlets and mainwheel brakes. The fly­by-wire system governed pitch control by the tailplanes used in unison, and provided three – axis stabilization. The mechanical controls worked directly by the pilot’s linkages to the surface power units governed the ailerons and rudder. The five internal fuel tanks were automatically controlled to supply fuel with­out disturbing the aircraft centre of gravity. A special oxygen system was provided to en­sure engine restart and afterburner light-up at high altitude. T10-1 was built with no provi­sion for armament, but in its modified state it had seven hardpoints on which external stores could be suspended.

Despite the fact that the basic aircraft had to be completely redesigned, the T-10 family of prototypes were stepping stones to the greatest fighter of the modern era.

Purpose: Experimental ground-attack aircraft.

Design Bureau: OKB-1, formed of German engineers led by Dipl-Ing Brunolf Baade, at Podberez’ye.

In November 1944 beleaguered German de­sign teams worked round the clock with ‘crash’ programmes intended to meet an RLM (Reich Air Ministry) specification for a minia­ture fighter designed to produce effective last – ditch defence. At the Junkers company the most important proposal was the EF (En- twicklungs Flugzeug, development aircraft) 126, code-named Elli. This was to be a small fighter powered by one of the Argus pulsejets already in mass-production for the Fi 103 flying bomb. Messerschmitt already had such an air­craft, the Me 328, powered by two of these units, testing of which showed that the violent vibration of the engines had a severe effect on the airframe and pilot. The EF 126 was small­er, almost a copy ofthe FilOSR Reichenberg, the piloted version of the flying bomb. In late 1944 it was decided that, because of poor pulsejet performance at altitude, the mission should be changed to ground attack. Despite frantic work little hardware appeared before Germany collapsed. A German three-view has been found bearing the date 9th May 1945, the day after the final surrender! Moreover, the span quoted (6.35m) is different from that given in other early-May documents, showing that the design was still fluid. Indicative of the panic environment, the data panel on this drawing gives the length as 8.9m while the drawing itself gives the same length as that below! Despite this, and the primitive nature of the project, the EF 126 was snapped up by the Russians. In October 1945 the Soviet MAP (ministry of aviation industry) organised the Junkers workers into an EF 126 cell at Dessau, headed by Prof Brunolf Baade. The intention was that this group would be moved to the USSR, but the EF 126 cell remained at Dessau while the much larger group working on jet bombers formed OKB-1 at Podberez’ye (see next entries). By January 1946 an engineering mockup had been built and parts for five air­craft produced. The EF 126 VI (first prototype) was ready in May 1946, and flight testing opened on 12th May with the VI towed as a glider behind a Ju 88. The pilot was Mathis and the tug pilot Schreiber. The EF 126 was cast off and made a normal landing. However, on 21st May Mathis was killed, after he had misjudged his glide approach, bounced hard on the rear skid, rolled to the right and cartwheeled. MAP granted permission for the resumption of test-

Top.- EF 126 in wind tunnel.

EF 126/EF 131

ing in July, after modification of the leading edge. The new pilot, Huelge, was pleased by the modified aircraft, which by this time was making rocket take-offs from a ramp. The new pulsejet engine caused problems, take-off rockets ran out, and an MAP commission headed by A S Yakovlev rejected the EF 126 as an operational vehicle because of ‘weak ar­mament, absence of armour and insufficient fuel…’ It gave permission for work to continue to help develop the engine, ramp launch and skid landing. In September 1946 V2, V3 and V4 were sent to LII (today called Zhukovskii), sup­ported by 18 specialists headed by Ing. Bessel. Further delays were caused by design changes, but gliding flights after a tow by Ju 88 resumed with V5 on 16th March 1947. The MAP directive that three aircraft should take part in the Tushino display came to nothing, but by the end ofthe year V3 and V5 had made 12 short flights, five ofthem under power. The Jumo 226 engine made 44 test flights slung under a Ju 88, but predictably the whole pro­gramme was cancelled at the start of 1948.

The EF126 resembled the FilOS flying bomb in many respects, except that instead of a war­head the nose contained the cockpit, the wings had 3° dihedral (and like some flying bombs were made of wood) and housed fuel tanks, and skid landing gear was fitted (the original Junkers drawings showed retractable tricycle gear). One drawing shows a single large retractable skid, but the prototypes had two small skids in tandem. The wing was fitted with pneumatically driven flaps, and a braking parachute was housed in the rear fuselage. The original intention was to have twin fins. EF 126 VI was fitted with the standard flying – bomb engine, the Argus 109-014 rated at 350kg (772 Ib) thrust at sea level. All subsequent air­craft had the 109-044, which Junkers took over as the Jumo 226, rated at 500kg (1,102 Ib). De­spite prolonged testing this suffered from diffi­cult ignition, poor combustion and dangerous fires. Three tanks housed 1,320 litres (290 Im­perial gallons) of fuel, fed by air pressure. Ramp take-off was by two solid motors each with an impulse of 12,000kg-seconds. Arma­ment comprised two MG 151/20, each with 180 rounds, plus an underwing load of two AB 250 containers, each housing 108 SD2 ‘butter­fly bombs’, or 12 Panzerblitz hollow-charge bomblets.

A good idea for a last-ditch weapon was un­likely to survive in the post-war era of rapid technical development.

Arranged principally in alphabetical order

AlekseyevI-218

Purpose: To provide a high-performance Shturmovik, armoured ground-attack aircraft.

Design Bureau: Semyon Mikhailovich Alekseyev OKB-21, at Gorkii.

Born in 1909, Alekseyev graduated from MAI in 1937, and became one of the principal de­signers in the OKB of S A Lavochkin. Respon­sible for major features of the LaGG-3 and La-5 family of fighters, he was head of detail design on the derived La-7 and La-9. In 1946 he was able to open his own design bureau. He at once concentrated on twin-jet fighters with nosewheel landing gear, getting the

I-211 into flight test on 13th October 1947. Whilst working on derived aircraft with more powerful engines and swept wings, he worked in parallel on a family of multirole ground – attack aircraft.

The first of these was the I-218, or I-218-1. For various reasons, the most important being the need for long endurance at low al­titude, Alekseyev adopted a powerful piston engine. He adopted a pusher layout, with the tail carried on twin booms.

A single prototype was completed in sum­mer 1948, but in August of that year OKB-21 was closed. (A contributory factor was Yakov­lev’s scathing comment that Alekseyev’s jet

fighters were copies ofthe Me 262.) At closure three derived aircraft were on the drawing board. The I-218-Ib (I-219) had a revised crew compartment, tailwheel landing gears and swept vertical tails. The I-218-11 (I-221) was an enlarged aircraft with a conventional fuselage and tail, powered by a Lyul’ka TR-3 turbojet, which was being developed to give 4,600kg (10,141 Ib) thrust. The I-218-III (I-220) was a variation on the 218-11 with a very powerful piston engine (he hoped to get a Dobrynin VD-4 of4,000hp, as used in the Tu-85 but with­out the turbo). Alekseyev was sent to CAHI (TsAGI) and then as Chief Constructor to the OKB-1 team of former German (mainly

Junkers) engineers to produce the Type 150, described later under OKB-1.

No detailed documents have been discov­ered, but the I-218 was a modern all-metal stressed-skin aircraft designed to a high (fighter type) load factor. The wing com­prised a centre section and outer panels joined immediately outboard of the tail booms. It was tapered on the leading edge only, and on the trailing edge were fitted out­board ailerons and six sections of area-in­creasing flap. The tail booms projected far in front of the wing, and carried a conven­tional twin-finned tail with a fixed tailplane joining the fins just above the centreline of the propeller.

The forward fuselage contained a com­partment for the pilot and for the aft-facing gunner. Like some highly-stressed parts of the airframe this was made of the new 30- KhGSNA chrome-nickel steel, and it was thick enough to form a ‘bathtub’ to protect against armour-piercing shells of 20mm cali­bre. The windows were very thick multilayer glass/plastics slabs. The engine, mounted on
the wing, was a Dobrynin VM-251 (in effect, half a VD-4, with three banks each of four cylinders) rated at 2,000hp. It drove an AV-28 contra-rotating propeller arranged for pusher propulsion, comprising two three-blade units each of 3.6m (11ft l0in) diameter.

The I-218 was intended to have heavy for­ward-firing armament, such as four NR-23 guns each with 150 rounds or two N-57 (30 rounds each) and two N-37 (40 rounds each). In addition provision was to be made for up to 1,500kg (3,307 Ib) of bombs or other stores, carried mainly under the fuselage, or six 132mm (5.2in) rockets or 16 RS-82 rockets carried under the wings.

For defence, the backseater could operate a remotely-sighted system controlling an NR-23 cannon on the outer side of each tail boom. Each of these powerful guns was fed from a 120-round magazine, and was mount­ed in a powered barbette with angular limits of ±25° vertically and 50° outwards. Avionics included 12RSU-10 radio, RPKO-10M radio­compass, RV-2 radar altimeter and SPU-5 intercom.

Though the I-218 was built there is no posi­tive evidence that it flew, apart from the fact that the specification does not include the word ‘estimated’ for the flight performance. The fact is, in 1948 such aircraft were regard­ed as obsolescent. A rival, also abandoned, was the IL-20, described later.

Purpose: To attempt once more to fly on human muscle power.

Design Bureau: B I Cheranovskii.

Undeterred by the total failure of BICh-16, Cheranovskii persevered with the idea of fly­ing like a bird and designed the totally different BICh-18. The name meant ‘muscle-power’. On 10 th August 1937 pilot R A Pishchuchev, who weighed 58kg (1281b), glided 130m (4261/2ft) off a bungee launch, without ped­alling. He then did a pedalling flight, achieving six wing cycles. He reported ‘noticeable for­ward thrust’, and flew 450m (1,476ft). Sus­tained flight was considered impossible.

The BICh-18 vaguely resembled a perfor­mance sailplane with a cockpit in the nose and conventional tail. Much of the structure was balsa. There were two wing sets, com­prising the lower left and upper right wings forming one unit and the upper left and lower right forming the other. Both sets were mounted on pivots on top of the fuselage and arranged to rock through a ±5° angle by cock­pit pedals. As the wings rocked, their tips never quite touching, the portion of each wing aft of the main spar was free to flap up and down to give propulsive thrust. One re­port states that the outer trailing-edge por­tions were ailerons.

If the evidence is correct this odd machine was one of the few human-powered aircraft to have achieved anything prior to the 1960s.

Dimensions

Span 8.0m 26 ft 3 in

Length 4.48m 14 ft 814 in

Wing area 10.0m2 108ft2

Weights

Empty 72 kg 1591b

Loaded 130kg 287 Ib

Purpose: To test a small sporting aircraft of tailless design.

Design bureau: B I Cheranovskii.

This attractive little machine was rolled out on skis in late 1937 and first flown in 1938. Later in that year it was fitted with a more powerful engine, and with wheel landing gear. Extensive testing, which included sus­tained turns at about 35° bank at different heights, showed that the BICh-20 was stable and controllable, and also could land very slowly.

This aircraft was again a wooden structure, with ply over the leading edge and the vesti­gial fuselage. The wing marked a further change in aerodynamic form: having started with ‘parabola’ designs, Cheranovskii switched to delta (triangular) shapes, and with the BICh-20 adopted a more common form with straight taper, mainly on the lead­ing edge. Trailing-edge controls comprised inboard elevators and outboard ailerons, with prominent operating levers. To enter the cockpit the pilot hinged over to one side the top of the fuselage and integral Plexiglas canopy which formed the leading edge of the fin. The aircraft was completed with Chera – novskii’s ancient British 18hp Blackburne en­gine, in a metal cowling, and with sprung ski landing gear. It was later fitted with wheels, including a tailwheel, and a 20hp French Aubier-Dunne engine.

All known records suggest that this aircraft was completely successful.

Purpose: To use the tailless concept in a more powerful aircraft for racing.

Design Bureau: B I Cheranovskii.

By the late 1930s Cheranovskii was confident that he could apply his unusual configuration, with no separate horizontal tail, to aircraft in­tended to reach much greater speeds. For the big All-Union race organised by Osoaviakhim to take place in August 1941 he designed a minimalist aircraft broadly like the BICh-20 but with a far more powerful engine. Also designated SG-1, from Samolyot Gonochnyi, aeroplane for racing, it was completed in 1940, but not flown until June 1941. The Ger­
man invasion of 22nd June resulted in the race being cancelled.

With a configuration almost identical to that of the BICh-20, the BICh-21 was likewise all-wood, with polished shpon skin except over the metal engine cowl and cockpit canopy. Unlike the BICh-20 the wing was made as a centre section (with anhedral) and outer panels. This in turn resulted in a differ­ent arrangement of trailing-edge controls, these having reduced chord, with a signifi­cant portion ahead of the trailing edge of the wing, with the elevators divided into two
parts on each side. The engine was an MV-6, the Bessonov licence-built Renault with six aircooled cylinders, rated at 270hp. It drove an imported Ratier two-blade two-pitch (fine or coarse) propeller. A small fuel tank was in­side each side of the centre section. Immedi­ately outboard of these were the landing gears, which retracted backwards under pneumatic pressure.

No records survive of this aircraft’s han­dling or of its fate.

Purpose: To investigate a new aerodynamic configuration.

Design Bureau: B I Cheranovskii, by this time working at the MAI (Moscow Aviation Institute).

From 1947 Cheranovskii headed an OKB at the MAI, whose excellent facilities he used in a series of tailless projects. This glider was de­signed in winter 1948-49, and test flown by IA Petrov at Tushino from 17th July 1949.

Having progressed from the ‘parabola’ to a form of delta and then to a wing of normal ta­pered shape, this glider comprised a broad flat lifting fuselage, to which were attached conventional wings with modest sweepback. A further innovation was to use more con­ventional trailing-edge controls, mounted on the wing instead of below it. The original Che – 22 drawings show no vertical surfaces what­ever, but later fixed fins were added on the wingtips.

Flight testing appeared to go well, and in late 1949 the DOSAV repair shops tooled up to put the Che-22 into production. Unfortunate­ly, while testing the first to come off the as­sembly line Petrov crashed and was killed, and production was abandoned.

Performance

Not recorded, but ‘aerodynamic efficiency’ (lift/drag ratio) was 18.

Purpose: To devise an improved configuration for a tactical attack aircraft. Design Bureau: Moscow Aviation Institute, designer Pyotr Grushin.

Born in 1906, Grushin worked on various air­craft at MAI, as well as a remarkable steam engine tested in a U-2 (Po-2). In 1935he began scheming a tandem-wing aircraft, thinking this could form the basis of an attack aircraft with a rear gun turret. The single example of the Sh-Tandem (Shturmovik-Tandem) was constructed in the Institute’s production training school. It was exhaustively tested by P M Stefanovskii from 5th December 1937. Once the dangerously inadequate directional (yaw) stability had been corrected, by adding fins and rudders above the tailplcine, the air­craft flew well. Eventually it was judged to be unreliable and not really needed, but a deriv­ative with armour, an M-82 engine and a can­non in the turret might have proved very useful.

The key feature of this aircraft was that it had a main wing and a rear wing with 45 per cent as much area, both having R-l 1 aerofoil profile. After experimenting with elevens the control surfaces on the rear wing were linked to move in unison as elevators, all lateral con­trol being by the ailerons on the main wing. Fins and rudders were fitted at 50 per cent of the semi-span on the rear wing, initially on the underside only in order to leave a clear 250° arc offire for the electrically driven turret with a ShKAS. Four more ShKAS were to be fixed firing ahead from the main wing, but these cannot be seen in photographs. An in­ternal bay housed a 200kg (441 Ib) bombload. The engine was an M-87 (derived from the

Gnome-Rhone K14) radial rated at 930hp. The tailwheel was fixed but the neat main units had single legs and retracted into the wing. The airframe was constructed mainly of wood, with skins of delta bakelite-impreg – nated veneer. Other features included a three-blade variable-pitch propeller, Hucks starter dogs on the propeller shaft, cooling
gills behind the engine cowling, a ventral ducted oil cooler (repeatedly modified) and aft-sliding pilot’s canopy.

Despite its extraordinary appearance this aircraft was clearly basically successful. Whether a developed version could have done better than the Ilyushin Shturmovik is problematical.

GUDKOV Gu-1

Purpose: To see whether a safe aeroplane could be constructed from magnesium. Design Bureau: Moscow Aviation Institute.

As magnesium has a density of 1.74, com­pared with 2.7 for aluminium and almost 8 for typical steels, it seemed reasonable to the MAI management to investigate its use as a primary structural material. In 1932 such a project was authorised by Director A M Be- lenkovich and the GUAP (civil aviation min­istry), and a year later a design team was assembled under Professors S I Zonshain and A L Gimmelfarb, with construction led by N F Chekhonin. A neat four-seat low-wing monoplane was quickly designed, and flown about 600 times in 1934-39. It was also stati­cally tested at (CAHI) TsAGI.

The EMAI was also known as the E-MAI, Elektron MAI, EMAI-1, E-l, EMAI-I-34 and Sergo Ordzhonikidze. Elektron is the name of the alloy with Al, Mn and Zn, considerably stronger than pure Mg, which was used for most of the airframe. The straight-tapered wings were based on Steiger’s Monospar principles, with the ribs and single spar built up from square and tubular sections. The en­tire trailing edge was hinged, forming ailerons and plain flaps. The well-profiled fuselage was largely skinned in Elektron, the wings and tail being covered in fabric. On the nose
was the Salmson seven-cylinder radial en­gine, rated at 175hp, in a ring cowl and driving a two-blade propeller. The strut-braced tailplane was mounted high on the fin, and the rubber-sprung main landing gears had spats. The cockpit was covered by one sliding and one hinged canopy. Most of the structure was welded, but many joints were bolted so that they could be dismantled.

The EMAI-1 was judged to be a comple suc­cess, with a structure weight ’42 per cent lower than using aluminium, steel tube or wood’. The fire risk was not considered a se­rious hazard, and according to MAI the main reason for not taking the use of Elektron fur­ther was because in the USSR there was not enough spare electric power available to pro­duce the magnesium.

MAI-62 AND MAI-63

This designation applied to two aircraft or­dered from Mikoyan to assist development of the Tu-144 supersonic transport. They were also called MiG-211 (I for Imitator), and Ana­log. Both aircraft were taken from the assem­bly line of the MiG-21S, but were powered by a later engine, the R-13-300, rated at 6,490kg (14,308 Ib). This engine could provide a large airflow for blown flaps, but as the Tu-144 (and thus the 2I-11) was a tailless delta no such flaps could be fitted. The wing was totally new, being of an ogival shape with the root chord extending over almost the entire length of the fuselage. The quite sharp leading edge had the remarkable sweep angle of 78°, be­fore curving out to a sweep angle of 55° over the outer wings. There was no droop (down­ward camber) along the leading edge. On the
trailing edge of each wing were four fully powered surfaces, the inner pair being plain flaps and the outer pair elevens (surfaces act­ing as both elevators and ailerons). The wing was incredibly thin, thickness/chord ratio being only 2.3 per cent inboard and 2.5 at the tip. Thus, the control-surface power units were faired in underneath, the outer fairings extending over the entire chord of the wing. The wing leading edge was made detachable so that different shapes could be tested. Among other modifications was an increase in fuel capacity to 3,270 litres (719 Imperial gallons), and of course there was no provi­sion for armament. Partly because of a ‘chick­en and egg’ situation, in which Mikoyan was uncertain precisely what shape to make the wing, whilst the purpose of the Analog was to teach Tupolev how to design the Tu-144’s wing, the programme ran at least a year too late to assist the design of the SST. Eventually

0 VGudkov flew 23-11/1 on 18th April 1968, withcivilregistrationSSSR-1966, the intended first-flight year. The Tu-144 pilots flew this air­craft before first flying the 44-00 (first Tu-144) on 31st December 1968, with the 23-11/1 ac­companying it as chase aircraft. The 23-11/2 differed mainly in that all eight wing movable surfaces were elevens. It was first flown by

1 Volk in late 1969. Later its starboard wing upper surface was tufted, photographed by a camera on the fin (later a second camera was added looking back from behind the canopy). Most of the second aircraft’s flying was done with a large LERX (leading-edge root extension) giving increased area from the new curved front portion. The 2I-11/2 car­ried out extensive aerodynamic and control research before going to the WS Museum at Monino. The 2I-11/1 was crashed on 28th July 1970 by an LII pilot performing unauthorised low-level aerobatics. Mikoyan did not act on the suggestion of the main 23-11 test pilots that he should develop a fighter version.

Ye-8

So different in appearance as hardly to be considered a MiG-21 version, these two air­craft were considered as prototypes of a pos­sible improved fighter. They resulted from a Kremlin decree of spring 1961 calling for ‘a version of the MiG-21 capable of destroying hostile aircraft at night or in bad weather’. This was intended to become the MiG-23. The key feature was use of the Volkov KB’s Sapfir 21 (Sapphire) radar. This was far too bulky to fit inside any possible MiG-21 nosecone, and the answer was to feed the engine by a com­pletely new inlet under the fuselage. There was an advantage in doing this in that the inlet could be given variable geometry with mov-

Ye-6T/l (Ye-66A)

Photographs on the opposite page:

Top: MiG-21PD(23-31).

Centre left: MiG-211/1 with 44-00 (first prototype Tu-144).

Centre right: MiG-211/1.

Bottom: MiG-21 PD (23-31) at Domodedovo Air Parade, July 1967.

Photographs on this page:

Top left: MiG-211/2 with one wing tufted. Top right: Ye-8/2.

Right: Model of Ye-8 interceptor project.

Purpose: To test pressurized cockpits. Design Bureau: OSK (Department for Special Construction), Moscow, lead designerAleksei Y akovlevich Shcherbakov, and Central Construction Bureau (General Designer N N Polikarpov) where Shcherbakov also worked.

In 1935 Shcherbakov was sent to OSK to spe­cialize in the problems of high-altitude flight. He concentrated on the detailed engineering of pressurized cockpits, called GK (Ger – meticheskaya Kabina, hermetic cabin). By this time the BOK-1 had already been de­signed and was almost ready to fly, but Shcherbakov did not spend much time study­ing that group’s difficulties. His first GK was tested on S P Korolyov’s SK-9 sailplane, pre­decessor of the RP-318 described previously. The second was constructed in a previously built Polikarpov I-15 biplane fighter. Polikar-
pov’s biplane fighters were noted for their outstanding high-altitude capability, and from 1938 Shcherbakov spent most of his time as Polikarpov’s senior associate. The modified aircraft first flew in 1938. Later in the same year an I-15 was tested with a very much bet­ter GK. In 1939the definitive GKwas tested on an I-153, an improved fighter whose design was directed by Shcherbakov. The test-bed aircraft was designated I-153V (from Vysot – nyi, height). This cockpit formed the basis for those fitted to MiG high-altitude fighters, be­ginning with the 3A (MiG-7, I-222). Later Shcherbakov managed GK design for four other OKBs, and from 1943 created his own aircraft at his own OKB.

No details have been discovered of the first GK, for the SK-9, and not many of the second, fitted to an I-15 with spatted main landing gear. Like other aircraft of the 1930s, the I-15 fuselage was based on a truss of welded KhMA (chrome-molybdenum steel) tubing, with fabric stretched over light sec­ondary aluminium-alloy structure. Accord­ingly, Shcherbakov had to build a complete cockpit shell inside the fuselage, made ofthin light-alloy sheet. He had previously spent two years studying how to seal joints, and the holes through which passed wires to the con­trol surfaces and tubes to the pressure-fed in­struments. On top was a dome of duralumin,

Above right: I-153V.

Left. l – 153V cockpit.

hinged upwards at the rear. In this were set rubber rings sealing 12 discs ofPlexiglas, with bevelled edges so that internal pressure seat­ed them more tightly on their frames. Pilots said the view was unacceptably poor, as they had done with the original BOK-1. The instal­lation in the second aircraft, with normal un­spatted wheels, was a vast improvement. Overall pilot view was hardly worse than from an enclosed unpressurized cockpit (but of course it could not compare with the original open cockpit). The main design problem was the heavily framed windscreen, with an opti­cally flat circular window on the left and the SR optical sight sealed into the thick window in the centre. The main hood was entirely transparent and hinged upwards. Behind, the decking of the rear fuselage was also trans­parent. The I-153V had a different arrange­ment: the main hood could be unsealed and then rotated back about a pivot on each side to lie inside the fixed rear transparent deck.

Unknown in the outside world, by 1940 Shcherbakov was the world’s leading design­er of pressurized fighter cockpits.

Purpose: To modify a T-10 (Su-27) to set world records.

Design Bureau: P O Sukhoi, Moscow, General Constructor M P Simonov.

According to Simonov, The idea of entering a competition for world records for aircraft of this category was conceived during 1986. We realised that this aircraft was capable of doing many things. We were so confident that, for record setting, we decided not to build a ded­icated aircraft but took one of the pre-series ones which had already flown. This then had to be prepared in conformity with the strin­gent Federation Aeronautique Internationale rules. The aircraft was called the P-42 as a tribute to the turning point in the Stalingrad battle in November 1942, when Soviet avia­tion had played a large part in crushing the enemy’. The OKB organised a team of design engineers, test pilots and supporting ground staff under Chief Designer Rollan G Mar – tirosov (who later designed Ekranoplans). The modified aircraft was ready in October 1986. In two flights, on 27th October and 15th November 1986 Viktor Pugachev set eight climb-to-altitude records (four absolute and four for aircraft of up to 16 tonnes take-off weight): he reached 3km (9,843ft) in 15.573
seconds and 6km (19,685ft) in 37.05 seconds. On 10th March 1987 and 23rd March 1988 Nikolai Sadovnikov flew the P-42 to 9km (29,528ft) in 44.0 seconds, to 12km (39,370ft) in 55.20 seconds and to 15km (49,213ft) in 70.329 seconds. On 10th June 1987 Sadovni – kov set a world class record by sustaining an altitude of 19,335m (63,435ft) in level flight. Another record set by Pugachev was lifting a load of1 tonne (2,205 Ib) to 15km (49,213ft) in 81.71 seconds.

The aircraft selected was T10-15. It was simplified and its weight reduced until it was able to take off at a weight of 14,100kg (31,08515). With AL-31F engines uprated to 13,600kg (29,982 Ib) this gave a thrust/weight ratio of 1.93, believed to be the highest of any aircraft ever built. Modification to the equip­ment included removal of the radar and mili­tary equipment (including the GSh-301 gun and its ammunition container, wingtip mis­sile launchers and weapon hardpoints) and removal of avionics other than the flight, nav­igation and communications needed for safe flight. Modifications to the airframe included replacement of the nose radome by a metal fairing, simplification of the wings by in­stalling a fixed leading edge and a fixed struc­ture in place of the flaperons, removal of the
ventral fins and the tops of the fins, replace­ment of the airbrake by a fairing and simplifi­cation of the airbrake supporting structure, removal of the parabrake container, simplifi­cation of the variable engine inlets which were locked in their optimum positions, and removal of the mudguard from the nose – wheel. The aircraft was left unpainted.

The P-42 set a total of 27 world records.

Purpose: To improve a German design for a jet bomber.

Design Bureau: OKB-1, formed of German engineers led by Dipl-Ing Brunolf Baade, at Podberez’ye.

From late 1944 the Red Army overran many sites where German aircraft engineers had been working on jet aircraft and engines. The largest group had been in the employ of the vast Junkers Flugzeug und Motorenwerke in the Dessau area and at Brandis near Leipzig. At Brandis the principal project had been the Ju 287 jet bomber. Having flown the Ju 287 VI (a primitive proof-of-concept vehicle incor­porating parts of other aircraft) on 16th Au­gust 1944, work had gone ahead rapidly on the definitive Ju 287 V2, to be powered by two triple engine pods, but the Soviet forces over­ran Brandis airfield before this could fly. This work was clearly of intense interest, and with the aid of a large team of ex-Junkers engi­neers, who were prisoners, the programme was continued with all possible speed. The Ju 287 V2 stage was skipped, and parts of this aircraft were used to speed the construction of the next-generation EF 131 (Entwicklungs Flugzeug, meaning research aircraft). This was built at Dessau, dismantled, and, to­gether with many of the German engineers and test pilots, taken by train to Moscow. As explained in the next entry, they formed OKB-1. Final assembly took place at the test airfield then called Stakhanovo (today at LII Zhukovskii) where on or about 23rd May 1947 it was briefly flight tested by Flugkapitan Paul Julge. According to legend, he was never al­lowed enough fuel to reach ‘the West’. By this time more advanced aircraft and engines were being developed in the Soviet Union, and the EF 131 spent long periods on the ground. MAP Directive 207ss of 15th April 1947 had demanded that ‘two prototype EF – 131 with six RD-10 engines to take part in the August Tushino display…’ but this was im­possible to achieve. Eventually the first air­craft was again made airworthy and flown to Moscow’s other experimental airfield, Tyopliy Stan. On 21st June 1948 the order was given to stop EF 131 work. This was because it had been overtaken by the much better Type 140.

The EF 131 was an impressive-looking jet bomber, characterised by its swept-forward wing. To postpone the rapid increase in drag as Mach number exceeds about 0.75 German aerodynamicists had from 1935 studied wings swept either backwards or forwards. The FSW (forward-swept wing) appeared to offer important aeroelastic advantages, but because such wings diverge under increasing aerodynamic load they are structurally very difficult. The Ju 287 VI avoided this problem by being a slow-speed aircraft, but the prob­lem was met head-on by the 131 and 140, and also by the Tsybin LL-3 (which see). The first structurally satisfactory FSW was that of the Grumman X-29, almost 40 years later, and a more advanced FSW is seen in today’s Sukhoi S-37 (which see). Thus, the FSW of the EF 131 can be seen to have been an enor­mous challenge. Aerodynamically it was di­rectly derived from that ofthe wartime Ju 287, with considerable dihedral and a leading edge swept forward at 19° 50′. It was fitted with slats at the wing roots, slotted flaps and outboard ailerons. It was also fitted with mul­tiple spoiler/airbrakes (items 18 in the de­tailed drawing overleaf) and a total of eight shallow fences (in the drawing marked QV). Because of the limited (900kg, l,9841b) thrust of the Junkers Jumo 004B engines these were arranged in groups of three on each under­wing pylon. By late 1947 this engine was in limited production at Kazan as the RD-10, and because they were considered superior to the German originals the engines actually in­stalled were RD-lOs. The crew numbered three, and to save weight armour was omit­ted. A neat tricycle landing gear was fitted, the main tanks occupied the top of the fuselage, a braking parachute occupied a box under the tail, and at the end of the fuselage was a remotely sighted FA15 barbette with super­imposed MG 131 guns as fitted to some wartime aircraft such as the Ju 388.

The FSW and primitive engines made this an unattractive aircraft.

EF131

Centre: Page from EF 131 maintenance manual, Fig. 10 ‘covers and flaps’.

Bottom: EF 131 (the only known photograph, enlarged from distant background).