Category Soviet x-plenes

Design Bureau: OKB-155 of A I Mikoyan

Throughout the massive production of the MiG-15 and MiG-17, with a combined total ex­ceeding 22,000, the MiG OKB was eager to dis­card the British-derived centrifug al engine and build truly supersonic fighters with indigenous axial engines. It achieved this in sensible stages. The M, or I-350, introduced the large TR-3A axial engine and a wing with a leading – edge sweep of 60°. The SM-2, or I-360, pow­ered by twin AM-5 axial engines, at first was fitted with a high T-type tail. Then the tailplane was brought down to the fuselage, the design was refined, and as the SM-9 with afterburning engines (first flown 5th January 1954) achieved production as the MiG-19. The SM-9/3 intro­duced the one-piece ‘slab’ tailplane, with no separate elevator, and this was a feature of the MiG-19S. Powered by two RD-9B engines each with an afterburning rating of 3,250kg (7,1651b), this had the devastating armament of three NR-30 guns, each far more powerful than the British Aden of the same calibre. The following specification is for a typical MiG-19S.

SM-10

Though it had a generally longer range than its predecessors the MiG-19 was required in a decree of May 1954 to be developed with flight-refuelling capability. At that time the only tanker was a version of the piston-en­gined Tu-4, and a series MiG-19, callsign 415, was fitted with a probe above the left (port) wingtip, feeding into a large pipe with divert­ers and non-return valves to fill all the aircraft tanks. By 1956 testing had moved to an extra­ordinary test-bed, callsign 10, fitted with no fewer than four probes. One was at the bot­tom of the nose, another at top left on the nose, a third on the leading edge of the port
wing and the fourth projected with a kink from above the starboard wing.

SM-20

This was a MiG-19S modified as a pilotless aircraft to test the guidance system of the Kh – 20 cruise missile. This huge weapon was de­signed to be carried under a special version of the Tu-95 heavy bomber, and one Tu-95K was modified to carry and release the SM-20. Apart from being equipped with the missile’s guidance system and a special autopilot and various other subsystems, including a receiv­er link for remote-pilot guidance, the fighter was fitted with a position beacon, radar re­flector and destruct package. Suspension lugs were built in above the centre of gravity, and the parent aircraft had pads which pressed on each side of the SM-20 canopy. Tests began in October 1956. SM-20P de­scribed the aircraft after modification with special engines able to vaporise the fuel to ensure reliable starting at high altitudes.

SM-30

This designation applied to MiG-19 and MiG – 19S aircraft modified for ZELL (zero-length launching). Nuclear weapons clearly made it foolish to base combat aircraft on known air­fields, so the ZELL technique was intended to enable aircraft to be fired off short inclined launchers by a large rocket. The launcher was naturally made mobile, and most loca­tions were expected to be in the extreme Arc­tic such as Novaya Zemlya. The aircraft needed a strengthened fuselage, reinforced fuel tanks and mounts, a special pilot head­rest, and (in most cases) extra-large para – brakes or arrester hooks for short landings.

The usual rocket was the PRD-22, with a thrust of40,000kg (88,185 Ib) for 2.5 seconds. Manned firings took place from 13th April 1957, the chief pilots being G Shiyanov and Yu A Anokhin (not the more famous S N Anokhin). Results were satisfactory, but the scheme was judged impractical.

Purpose: To meet an IA-PVO demand for a high-performance automated interception system.

Design Bureau: OKB-51 ofP O Sukhoi, Moscow.

In late 1957 the threat of USAF strategic bombers able to cruise at Mach 2 (B-58) and Mach 3 (B-70) demanded a major up­grade in the PVO defence system. At the start of 1958 a requirement was issued for manned interceptors with a speed of 3,000km/h (l,864mph) at heights up to 27km (88,583ft). Mikoyan and Sukhoi responded. Creation of the T-3A-9 interception system was autho­rised by the Council of Ministers on 4th June 1958. The air vehicle portion of this system was a derivative of the T-3 designated T-3A, and with the OKB-51 factory designation T-37. Detail design of this aircraft took place in the first half of 1959. In February 1960 the single flight article was approaching completion when without warning the GKAT (State Com­mittee for Aviation Equipment) terminated the programme and ordered that the T-37 should be scrapped. The role was temporari­ly met by the Tu-128 and in full by the MiG-25P.

Though derived from the T-3 the T-37 was an entirely new aircraft which, because of aerodynamic guidance by CAHI (TsAGI) and the use of the same type of engine, had more in common with the MiG Ye-150. The T-3A-9 system comprised this aircraft plus the Looch (ray) ground control system, the ground and airborne radars, a Barometr-2 data link, Kremniy-2M (silicon) NPP (sight) system and two Mikoyan K-9 (R-38) missiles. The aircraft had a wing which was basically a strength­ened version of the T-3 wing, with no dog­tooth and with anhedral increased to 3° (ie, -3° dihedral). Each flap could be extended out on two rails to 25° and did not have an inner corner cut off at an angle. A more im­portant change was that to avoid scraping the tail on take-off or landing the main landing gears were lengthened, which meant that the wheels were housed at an oblique angle in the bottom of the fuselage. The fuselage was totally new, with a ruling diameter of 1.7m (12ft 7in). This was dictated by the Tumanskii R-l5-300 afterburning turbojet, with dry and reheat ratings of 6,840kg (15,080 Ib) and 10,150kg (22,380 Ib) respectively. The TsP-1 radar was housed in a precisely contoured radome whose external profile formed an Os – watitsch centrebody with three cone angles to focus Shockwaves on the sharp inlet lip. The whole centrebody was translated to front and rear on rails carried by upper and lower inlet struts. Surplus air could be spilt through two powered doors in each duct outer wall at Frame 8. The pressurized cockpit had a KS-2 seat and a vee windscreen ahead of a low- drag upward-hinged canopy with a metal­skinned fixed rear fairing. The detachable rear fuselage was made mainly of welded ti­tanium, and terminated in an ejector sur­rounding the engine’s own variable nozzle. Initially a sliding ring, this ejector was changed to an eight-flap design during proto­type manufacture. Ram air cooling inlets

were provided at Frames 25 and 29, and in the detachable rear section were four door-type airbrakes. Under this section were two radial underfins, each incorporating a steel bumper. Pivoted 140mm (51/2in) below mid­level the tailplanes had 5° anhedral and did not need anti-flutter rods as they were irre­versibly driven over a range of ±2°. Each main landing gear had levered-suspension carrying a plate-braked KT-89 wheel with an 800 x 200mm tyre. The long nose gear had a power – steered lower section with a levered-suspen – sion K-283 wheel with a 570x140mm tyre, and retracted backwards. A total of 4,800 litres (1,056 Imperial gallons) of fuel could be housed in three fuselage tanks (No 3 being of bladder type) and Nos 4 and 5 between wing spars 2 and 3. Provision was made for a 930 litre (204.6Imperial gallon) drop tank. Missile pylons could be attached ahead of the ailerons. Avionics included the radar, RSIU – 5A vhf/uhf with fin-cap antennas, RSBN-2 Svod (arch) navaid and SOD-57M transpon­der (both with fin slot antennas), Put (course) longer-range navaid, MRP-56P marker receiv­er, SRZO-2 Khrom-Nikel (chrome-nickel) IFF, Lazur (azure) beam/beacon receiver of the Looch/Vozdukh (rising) ground control sys­tem, KSI compass system and a ventral blade antenna for the flight-te st telemetry.

Like the rival Mikoyan Ye-150 series (which were produced more quickly) this weapon system was overtaken by later designs.

Dimensions

Span 8.56 m 28 ft 1 in

Length overall 1 9.4 1 3 m 63ft8!iin

Wing area (gross) 34 m2 366 ft2

(net) 24.69 m2 265.8ft2

Weights

Empty 7,260kg 16,005Ib

Loaded (normal) 1 0, 750 kg 23,699 Ib

(maximum) 12 tonnes 26,455 Ib

Performance (estimated)

Max speed at 15 km (49,21 3 ft) 3,000 km/h Service ceiling 25-27 km

Range 1,500km

(with external tank) 2,000 km

Two artist’s impressions of a T-37.

Purpose: High-speed research aircraft with fighter-likepossibilities.

Design Bureau: SNII, at Factory No 240.

One of the few aircraft designers to emigrate to (not from) the infant Soviet Union was Roberto Lodovico Bartini. A fervent Commu­nist, he chose to leave his native Italy in 1923 when the party was proscribed by Mussolini. By 1930 he was an experienced aircraft de­signer, and qualified pilot, working at the Central Construction Bureau. In April of that year he proposed the creation of the fastest aircraft possible. In the USSR he had always suffered from being ‘foreign’, even though he had taken Soviet citizenship, and nothing was done for 18 months until he managed to en­list the help of P I Baranov, head of the RKKA (Red Army) and M N Tukhachevskii (head of RKKA armament). They went to Y Y Anvel’t, a deputy head at the GUGVF (main directorate of civil aviation), who got Bartini established at the SNII (GVF scientific test institute). Work began here in 1932, the aircraft being desig­nated Stal’ (steel) 6, as one of a series of ex­
perimental aircraft with extensive use ofhigh – tensile steels in their airframes. After suc­cessful design and construction the Stal’-6 was scheduled for pre-flight testing (taxi runs at increasing speed) in the hands of test pilot Andrei Borisovich Yumashev. On the very first run he ‘sensed the lightness of the con­trols., .which virtually begged to be airborne’. He pulled slightly back on the stick and the aircraft took off, long before its scheduled date. The awesomely advanced aircraft proved to be straightforward to fly, but the en­gine cooling system suffered a mechanical fault and the first landing was in a cloud of steam. Yumashev was reprimanded by Barti­ni for not adhering to the programme, but testing continued. Yumashev soon became the first pilot in the USSR to exceed 400km/h, and a few days later a maximum-speed run confirmed 420km/h (261 mph), a national speed record. One of Bartini’s few friends in high places was Georgei K Ordzhonikidze, People’s Commissar for Heavy Industries. In November 1933, soon after the Stal’-6 (by this time called the El, experimental fighter) had
shown what it could do, he personally or­dered Bartini to proceed with a fighter de­rived from it. This, the Stal’-8, was quickly created in a separate workshop at Factory 240, and was thus allocated the Service des­ignation of I-240. Hearing about the Stal’-6’s speed, Tukhachevskii called a meeting at the Main Naval Directorate which was attended by many high-ranking officers, including heads from GUAP (Main Directorate of Avia­tion Production), the WS (air force), RKKA and SNII GVF. The meeting was presided over by Klementi Voroshilov (People’s Commissar for Army and Navy) and Ordzhonikidze. At this time the fastest WS fighter, the I-5, reached 280km/h. The consensus of the meeting was that 400km/h was impossible. Many engineers, including AAMikulin, de­signer of the most powerful Soviet engines, demonstrated or proved that such a speed was not possible. When confronted by the Stal’-6 test results, and Comrade Bartini him­self, the experts were amazed. They called for State Acceptance tests (not previously re­quired on experimental aircraft). These began

in the hands of Pyotr M Stefanovskii on 8th June 1934 (by which time the fast I-16 mono­plane fighter was flying, reaching 359km/h). On 17th June the Stal’-6 was handed to the Nil WS (air force scientific research institute), where it was thoroughly tested by Ste – vanovskiy and N V Ablyazovskiy. They did not exceed 365km/h, because they found that at higher speeds they needed to exert consider­able strength to prevent the aircraft from rolling to port (an easily cured fault). On 13th July the landing-gear indicator lights became faulty and, misled, Stefanovskii landed with the main wheel retracted. The aircraft was re­paired, and the rolling tendency cured. Vari­ous modifications were made to make the speedy machine more practical as a fighter. For example the windscreen was fastened in the up position and the pilot’s seat in the raised position. Aftervarious refinements Ste­fanovskii not only achieved 420km/h but ex­pressed his belief that with a properly tuned engine a speed 25-30km/h higher than this might be reached. The result was that fighter designers – Grigorovich, Polikarpov, Sukhoi and even Bartini himself – were instructed to build fighters much faster than any seen hith­erto. Bartini continued working on the StaP-8, a larger and more practical machine than the Stal’-6, with an enclosed cockpit with a for­ward-sliding hood, two ShKAS machine guns and an advanced stressed-skin airframe. The engine was to be the 860hp Hispano-Suiza HS12Ybrs, with which a speed of 630km/h (391 mph) was calculated. Funds were allo­cated, the Service designation of the Stal’-8 being I-240. This futuristic fighter might have been a valuable addition to the WS, but Bar­tini’s origins were still remembered even in the mid-1930s, and someone managed to get funding for the Stal’-8 withdrawn. One reason put forward was vulnerability of the steam cooling system. In May 1934 the I-240 was abandoned, with the prototype about 60 per cent complete.

Everything possible was done to reduce drag. The cantilever wing had straight taper and slight dihedral (existing drawings incor­rectly show a horizontal upper surface). The two spars were made from KhMA (chrome – molybdenum steel) tubes, each spar com­prising seven tubes of 16.5mm diameter at the root, tapering to three at mid-semi-span and ending as a single tube of 18mm diame­ter towards the tip. The ribs were assembled from Enerzh-6 (stainless) rolled strip. Ailerons, flaps and tail surfaces were assembled from steel pressings, with Percale fabric skin. The flaps were driven manually, and when they were lowered the ailerons drooped 5°. Barti­ni invented an aileron linkage which adjusted stick force according to indicated airspeed (this was resurrected ten years later by the Central Aero-Hydrodynamic Institute as their
own idea). The fuselage was likewise based on a framework of welded KhMA steel tubes. Ahead of the cockpit the covering comprised unstressed panels of magnesium alloy, the aft section being moulded plywood. In flight the cockpit was part-covered by a glazed hood flush with the top of the fuselage, giving the pilot a view to each side only. For take-off and landing the hood could be hinged upwards, while the seat was raised by a winch and cable mechanism. Likewise the landing gear was based on a single wheel on the centre­line, with an 800 x 200mm tyre, mounted on two struts with rubber springing. The pilot could unlock this and raise it into an AMTs (light alloy) box between the rudder pedals. For some reason the fuselage skin on each side of this bay was corrugated. The wheel bay was normally enclosed by a door which during the retraction cycle was first opened to admit the wheel and then closed. Extension was by free-fall, finally assisted by the cable until the unit locked. Under the outer wings were hinged support struts, likewise retract­ed to the rear by cable. When extended, each strut could rotate back on its pivot against a spring. Under the tail was a skid with a rubber shock absorber. The engine was an imported Curtiss Conqueror V-1570 rated at 630hp, dri­ving a two-blade metal propeller with a large spinner (photographs show that at least two different propellers were fitted). This massive vee-12 engine was normally water-cooled, but Bartini boldly adopted a surface-evapora­tion steam cooling system. The water in the engine was allowed to boil, and the steam flowed into the leading edges of the wings which were covered by a double skin from the root to the aileron. Each leading edge was electrically spot – and seam-welded, with a soldering agent, to form a sealed box with a combined internal area of 12.37m2 (133ft2).

Each leading edge was attached to the upper and lower front tubes of the front spar. Inside, the steam, under slight pressure, condensed back into water which was then pumped back to the engine. The system was not de­signed for prolonged running, and certainly not with the aircraft parked.

Bartini succeded brilliantly in constructing the fastest aircraft built at that time in the So­viet Union. At the same time he knew per­fectly well that the Stal’-6 was in no way a practical machine for the WS. The uncon­ventional landing gear appeared to work well, and even the evaporative cooling sys­tem was to be perpetuated in the I-240 fight­er (but that was before the Stal’-6 had flown). Whether the I-240 would have succeded in front-line service is doubtful, but it was the height of folly to cancel it. The following data refers to the Stal’-6.

Purpose: To create a Vintokryl (screw wing) compound helicopter.

Design Bureau: OKB ofNikolai Kamov, Moscow.

In 1951 various attempts were being made to increase the effective range of helicopters, notably by towing them in the outward direc­tion behind an Li-2, with the lifting rotor au- torotating. The idea occurred to Kamov designer Vladimir Barshevsky that it would be possible to dispense with the tug aircraft if a helicopter could be provided with wings and an aeroplane propulsive system. After obtain­ing permission from Kamov, his deputy V V Nikitin took a proposal to the Kremlin and in a matter of days the OKB had a Stalin di­rective to get started. The engines were to be TV-2 (later TV-2VK) turboshafts supplied by N D Kuznetsov, and many organizations were involved in research for this challenging pro­
ject, starting with model tests in the T-l 01 tun­nel at CAHI. The final go-ahead was issued on 11 th June 1954. An order for three Ka-22s was placed on the factory at Ukhtomskaya, which had been derelict since Kamov was evacuat­ed from there in October 1941. Concentration on the small Ka-15 (the OKB’ sfirstproduction helicopter) and other problems so delayed the programme that on 28th March 1956 pro­totypes 2 and 3 were cancelled. In June 1958 the LD-24 rotor blades began testing on an Mi-4. The Ka-22 itself first lifted from the ground on 17th June 1959, and made its first untethered flight on 15th August 1959, the test crew being led by pilot D K Yefremov. Serious control difficulties were encoun­tered, and the Kamov team were joined by LII pilots VVVinitskii and YuAGarnayev. Though still full of problems the Vintokryl was demonstrated on llth October 1959 to MAP Minister PVDement’yev and WS C-in-C

KAVershinin. Gradually difficulties were solved and in July 1960 an order was received to manufacture three Ka-22s at GAZ No 84 at Tashkent, with D-25VK engines. On 23rd May 1961 a speed of230km/h was held for 37 min­utes. On 9th July 1961 the Ka-22 caused a sen­sation at the Aviation Day at Tushino. On 7 th October 1961, with spats over the wheels and a fairing behind the cockpit, a class speed record was set at 356.3km/h (221.4mph), followed on 12th October by 336.76km/h (209.3mph) round a 100km circuit. The spats and fairing were then removed and on 24th November 1961 a payload of 16,485kg (36,343 Ib) was lifted to 2,557m (8,389ft). Preparations were then made to ferry AM 0I – 01 and the third machine AM 0I-03 from Tashkent to Moscow for Nil acceptance test­ing. Both departed on 28th August 1962. While making an intermediate stop at Dzhusaly 0I-01 rolled to the left and crashed inverted, killing Y efremov and his crew of six. The cause was diagnosed as ‘disconnection of No 24 cable joint of the linkage with the starboard lift rotor collective-pitch control unit’. At Tashkent and in Turkestan the cable joints and cyclic-pitch booster brackets were inspected on 0I-02 and 0I-03 and found to be incorrectly assembled. Changing the direc­tion of rotation of one lifting rotor did little at lower speeds and caused problems at higher speeds – ‘When’, said lead engineer V S Dor – dan, ‘Shockwaves off the blades sounded like a large machine gun’. To improve stability and controllability the complex AP-116 differ­ential autopilot was installed, continuously sensing attitude and angular accelerations, feeding the KAU-60A combined flight-control unit. On 12th August 1964 the heavily instru­mented 0I-03 took off on one of a series of tests conducted with WS (air force) and GVF (civil) crews. Take-off was in aeroplane mode, and 15 minutes later at 310km/h (193mph) the aircraft suddenly turned to the right, ‘not arrested by full rudder and aileron.. .the aircraft turned almost 180° when Garnayev intervened, considering the prob­lem was differential pitch of the pro – pellers…turn rate slowed, but the aircraft pitched into a steep dive…the engineer jetti­soned the flight-deck hatches, and one struck the starboard lift rotor causing asymmetric forces which resulted in separation of the en­tire starboard nacelle. Garnayev ordered the crew to abandon the aircraft’. Three survived, but Col S G Brovtsev, who was flying, and technician A F Rogov, were killed. By this time the Mi-6 heavy helicopter was in wide service, and the Ka-22 was ultimately aban­doned. Several years later the two surviving machines, 0I-02 and 0I-04, were scrapped.

An article about the Ka-22 in Kryl’ya Rodiny (Wings of the Motherland) for November 1992 does not mention the fact that two crashed, which is not widely known even in the former Soviet Union.

The Ka-22 was basically an aeroplane with its engines on the wingtips, with geared dri­ves to both propellers and lifting rotors. The airframe was all light alloy stressed-skin, the high wing having powered ailerons and plain flaps. The fuselage had a glazed nose, three – seat cockpit above the nose and a main cargo area17.9 x 3.1 x 2.8m (58′ 9" x10′ 2" x 9′ 2") for 80 seats or 16.5 tonnes of cargo. The entire nose could swing open to starboard for load­ing bulky items or a vehicle. The original pro­totype was powered by 5,900-shp TV-2VK engines, but these were later replaced by the 5,500-shp D-25VK. These had free turbines geared via a clutch to the main-rotor and via a front drive to the four-blade propeller and a fan blowing air through the oil cooler from a circular inlet above the nacelle. The two free – turbine outputs were interconnected by a 12- part high-speed shaft ‘about 20m long’. The main rotors were larger derivatives of those of the Mi-4. In helicopter mode the propeller drive was declutched and the flaps were fully lowered. Flight control was by differential cyclic and collective pitch. In aeroplane mode the lifting rotors were free to windmill and the aircraft was controlled by the ailerons and tail surfaces. The twin-wheel landing gears were fixed.

Apart from prolonged dissatisfaction with the engines, the problems with the Ka-22 were mechanical complexity, severe losses in the gearboxes and drives and the fact that each lifting rotor blew straight down on top of the wing. Similar charges could be levelled against today’s V-22 Osprey.

Purpose: To create a fighter with unprecedented speed.

Design Bureau: Aleksandr Sergeyevich Moskalyov, initially in Leningrad and later at the VGU and Aircraft Factory No 18, Voronezh.

Moskalyov was a talented young designer/ pilot who achieved success with convention­al aircraft, notably the SAM-5 light transport (SAM stood for Samolyot [aeroplane] Alek­sandr Moskalyov). He also persistently strove to create highly unconventional aeroplanes of tailless configurations. The first of the latter series was the Sigma, named for the letter of the Greek alphabet. He sketched this in 1933 whilst working at the Krasnyi Letchik (Red flyer) factory in Leningrad, and worked on rocket propulsion with V P Glushko in a seri­ous endeavour to design an aeroplane to reach l,000km/h (621 mph), and if possible to exceed Mach 1 (the first project in the world with this objective). When it was clear that a rocket engine with adequate thrust was many years distant, he recast the design with piston engines. He was working on this when he left Leningrad to be a lecturer at the VGU, the State University at Voronezh. Under the guid­ance of A V Stolyarov he tested models in the VGU’s newly built high-speed tunnel. In September 1934 he submitted his preliminary report on SAM-4 to the GlavAviaProm (direc­torate of aircraft industries), whose Director, 11 Mashkevich, berated Moskalyov for sub­
mitting such ‘unimaginable exotics’.

By 1933 Moskalyov had decided a suitable configuration for a fast aircraft was an all­wing layout with a ‘Gothic delta’ plan shape, with trailing-edge elevens and Scheibe sur­faces (fins and rudders on the wingtips). The drawing shows two main wheels in the front view, but this may be an error as Moskalyov favoured a single centreline gear and, as shown, skids on the wingtip fins. The drawing shows a single propeller, but in fact Moskaly-
ov intended to use two Hispano-Suiza 12 Ybrs engines, each of 860hp (these were later made in the USSR under licence as the M-100), driving separate contra-rotating pro­pellers. The stillborn rocket version would have had a prone pilot, but the piston-en­gined SAM-4 featured a conventional en­closed cockpit; the designer did not explain why this was offset to port.

This proposal was altogether too ‘far out’ for Mashkevich. No data survives.

Purpose: To test an aeroplane with landing gears on the centreline.

Design Bureau: S A Moskalyov at VGU and GAZNolS.

Unaware of the fact that Bartini had already flown the Stal’-6 (see page 16), Moskalyov de­cided in 1933 that it would be prudent to build a simple low-powered aeroplane to investi­gate the landing gear he proposed to use for his fighter, with a single mainwheel and skids under the wingtips and tail. It was flown in early 1934, but later in that year it was modi­fied into the SAM-65/s.

The SAM-6 had a conventional tail, though its moment arm was very short and the air­craft was dominated by its relatively huge wing. The structure was wood, with fabric – covered control surfaces. The engine was a three-cylinder M-23 rated at 65hp. Behind the small fuel tank was the open cockpit. The Scheibe fins were not fitted with rudders, and were described by the designer as ‘plates’. Initial testing was done in early 1934 on centreline tandem skis. Later the front ski was replaced by a wheel on a sprung leg in­side a trouser fairing. After rebuilding as the SAM-66/s testing continued in 1935. This had tandem cockpits with hinged hoods, and in its final form a conventional landing gear was fitted with two trousered mainwheels.

According to Shavrov ‘experiments showed that the centreline gear was quite practical’. Moskalyov intended to use such landing gear on the SAM-7, but ultimately decided not to (see original drawing of that aircraft). The fol­lowing specification refers to the SAM-6t»/s.

Top right: SAM-6.

Purpose: To build a superior two-seat fighter.

Design Bureau: A S Moskalyov, at GAZ No 18, Voronezh.

In 1934 Moskalyov was engaged in engineer­ing later versions of TB-3 heavy bomber for production. This enabled him to use one of this bomber’s engines and propellers to power a fighter (though it was hardly ideal for the purpose). Despite the fact that it was far more complex than any of his previous air­craft, and also had advanced all-metal con­struction, the SAM-7 was completed in October 1935. Pilots considered it potentially dangerous, and factory testing was confined to taxying at progressively higher speeds, ulti­mately making short hops in a straight line.

The SAM-7’s configuration was described by Shavrov as ‘one of the world’s most un­
orthodox’, but in fact the wing was of fairly normal design, with straight equal taper and an aspect ratio of 4.6. Aerofoil profile was R – II, and the thickness/chord ratio 12 per cent, without twist. Apart from this the Sigma (the designer’s second use of this name) was in­deed unconventional. There was no tail. On the wingtips were Moskalyov’s favoured Scheibe fins, fitted with fabric-covered horn – balanced rudders. On the wing trailing edge were outboard ailerons and inboard eleva­tors which, when depressed to a slight angle, were intended also to serve as slotted flaps (though it is difficult to see how they could do so without putting the aircraft into a dive). The main landing gears had single struts, raked forward, with a track of 2.8m (9ft 2in), and were pivoted to the front spar to retract inwards. The surviving drawing shows a tail – wheel, but Shavrov says there was a non-cas-
toring tailskid. The structure was almost wholly Dl duralumin, the maximum wing skin thickness being 2.5mm. The nose inlet served the carburettors. The 830hp M-34 en­gine drove a four-blade wooden propeller, and was cooled by a surface evaporative (steam) system similar to that of the Stal’-6. For use at low speeds a normal honeycomb radiator could be cranked down behind the cockpit. The intended armament was two ShKAS fixed above the engine, fired by the pilot, and a second pair mounted on a pivot and aimed by the rear gunner.

One cannot help being astonished that Moskalyov was able to obtain funds to build this aircraft, because there is no mention of any official approval of the design (which would almost certainly have been refused). One feels sympathy with the test pilots, who were probably right to be hesitant.

Original OKB drawing of SAM-7.

Purpose: To test at modest speeds an aircraft with a ‘Gothic delta’ wing of very low aspect ratio.

Design Bureau: A S Moskalyov, from 1936 head of his own OKB-31 at Voronezh.

Always eager to build his incredible SAM-4 dart-like fighter, Moskalyov was rebuffed in these efforts until in 1936 US magazines fea­tured futuristic fighters with low-aspect-ratio wings, shaft drives and prone pilots. This spurred GUAP to invite Moskalyov at least to try out his radical ideas with a simple aircraft with an engine of modest power. Following tunnel tests by V P Gorskiy at CAHI (TsAGI), the SAM-9 was built in 70 days, and flown on skis in early 1937 by N S Rybko at Voronezh. Following six flights by Rybko and A N Gusarov, it was taken to Moscow and tested in short hops by Rybko and A P Chernavskii, finally making eight full flights in the hands of Rybko. The aircraft was tricky, demanding an angle of attack of 22° at take-off and landing, and being unable to climb higher than 1,500m (4,921ft). Despite this the NKAP (state com­missariat for aviation industry) suggested that Moskalyov should produce a fighter with a 0.975 aspect ratio wing, and this led to the RM – l. SAM-29.

The SAM-9 Strela (Arrow) was made of wood, with a brilliant surface finish, the cable-operated rudder and elevons having fabric covering. The thick aerofoil was of RAF.38 profile, with local modifications. The cockpit was placed between the two main spars, with a hinged canopy. The engine was a Renault MV-4 aircooled inverted 4-cylinder rated at 140hp. The neat main landing gears had pivoted rubber-sprung cantilever legs for skis or wheels, and the tailskid did not castor. The rudder and broad-chord elevons had trim tabs.

Without the support of CAHI (TsAGI) and the (mistaken) belief that such aircraft were planned in the USA, this project would prob­ably have got nowhere. As it was, the SAM-9 merely showed that such aircraft could fly,

but with difficulty. In a recent display ofmod – els of Moskalyov aircraft the SAM-9 was de­picted entirely doped red except for the propeller blades, and with a placard giving speed and altitude as 340km/h and 3,400m.

Purpose: To design a small fighter with ‘push/pull’ propulsion.

Design Bureau: A S Moskalyov, OKB -31 at Voronezh.

This small fighter was unconventional in lay­out, but used an ordinary wing, and had noth­ing to do with the designer’s previous fighter concepts. According to Shavrov ‘Fokker de­signed an almost exact copy of the SAM-13, known as the D.23…’ In fact it was the other way about, because Moskalyov began this de­sign in 1938, immediately after the D.23 had been exhibited at the Paris Salon. The single prototype was first flown by N D Fikson in late 1940, 18 months after the Dutch fighter, and proved difficult to handle, to need inordinate­ly long runs to take off and land, and to have a sluggish climb and poor ceiling. Its designer worked round the clock to improve it, and by
spring 1941 it was undergoing LII testing in the hands of Mark L Gallai. Apart from the fact the nose gear never did retract fully, it was by this time promising, and it was entered for the summer high-speed race, but the German in­vasion on 22nd June stopped everything. The No 31 OKB was evacuated, but this aircraft had to be left behind so it was destroyed. The OKB documents have not been found.

The SAM-13 was powered by two 220hp Renault MV-6 inverted six-cylinder aircooled engines driving 2.2m (7ft 21/2in) two-blade variable-pitch propellers. Between them was the pilot, and Moskalyov fitted the rear pro­peller with a rapid-acting brake to make it safer for the pilot to bail out. The small two – spar wing was sharply tapered, and was fitted with split flaps inboard of the booms carrying the single-fin tail. Apart from welded steel – tube engine mounts, the structure was wood­
en, with polished doped ply skin. The main landing gears retracted inwards and the nose unit aft. One drawing shows the nose unit (which had a rubber shimmy damper) to have had a levered-suspension arm for the axle. The intended armament, never fitted, comprised four 7.62mm ShKAS, two above the front engine and two at the extremities of the wing centre section.

Moskalyov knew that the MV-6 was avail­able for licence-production in the USSR, and thought this aircraft might make good use of some. Even had the programme continued without interruption it is hard to envisage the SAM-13 being adopted by the WS.

Purpose: To renew attempt to build a rocket-engined interceptor.

Design bureau: A S Moskalyov, No 31.

During the Great Patriotic War practical rock­et engines for manned aircraft became avail­able. Moskalyov never forgot that he had been invited by the NKAP to build a fighter with the so-called Gothic delta wing of 0.95 aspect ratio. In 1944, despite much other work, he collaborated with L S Dushkin in planning what was to be the ultimate Strela
fighter. This time most of the technology ex­isted, and S P Korolyov lent his support, but once the War was over such a project was judged to be futuristic and unnecessary. Moskalyov’s OKB was closed in January 1946, and he returned to lecturing, but he contin­ued to study this project for two further years.

The final SAM, also called Raketnyi Moska – lyov, would have followed the usual Strela form in having a Gothic delta wing and no horizontal tail. The wing was fitted with elevens and blended into a needle-nosed
fuselage carrying a large fin and rudder. The Dushkin RD-2M-3V engine, rated at 2,000kg (4,409 Ib) thrust at sea level and much more at high altitude, was installed at the rear and fed with propellants from tanks filling most of the airframe. Two cannon would have been installed beside the retracted nose landing gear.

This was yet another of this designer’s near misses, all of which stemmed from his abun­dance of enthusiasm.

No data survives.

Purpose: To improve the RSR further.

Design Bureau: OKB-256, Podberez’ye, later repeatedly transferred (see below).

Upon receipt of data from the NM-1, the RSR had to be largely redesigned. Construction was only marginally held up, and in early 1959 drawings for the first five pre-series R-020 air­craft were issued to Factory No 99 at Ulan-Ude. However, Tsybin’s impressive aircraft had their commercial rivals and political enemies, some ofwhom just thought them too ‘far out’, and in any case vast sums were being transferred to missiles and space. On 1st October 1959 President Khrushchyev closed OKB-256, and the Ministry transferred the RSR programme to OKB-23 (General Constructor VM Mya – sishchev) at the vast Khrunichev works. The Poberez’ye facilities were taken over by A Ya Bereznyak (see BI story). The Khrunichev management carried out a feasibility study for construction of the R-020, but in October 1960 Myasishchev was appointed Director of CAHI (TsAGI). OKB-23 was closed, and the entire Khrunichev facility was assigned to giant space launchers. The RSR programme was there­upon again moved, this time to OKB-52. At first this organization’s General Constructor V N Chelomey supported Tsybin’s work, but in­creasingly it interfered with OKB-52’s main programmes. In April 1961, despite the difficul­ties, the five R-020 pre-series aircraft were es­sentially complete, waiting only for engines. In that month came an order to terminate the pro­gramme and scrap the five aircraft. The work­force bravely refused, pointing out how much had been accomplished and how near the air­craft were to being flown. The management quietly put them into storage (according to

V Pazhitnyi, the Tsybin team were told this was ‘for eventual further use’). Four years later, when the team had dispersed, the aircraft were removed to a scrapyard, though some parts were taken to the exhibition hall at the MoscowAviation Institute.

The airframe of the 1960 RSR differed in sev­eral ways from the 1957 version. To avoid sur­face-to-air missiles it was restressed to enable the aircraft to make a barrel roll to 42km (137,800ft). The wings were redesigned with eight instead of five major forged and ma­chined ribs between the root and the engine. The leading edge was fitted with flaps, with maximum droop of 10°. The trailing edge was tapered more sharply, and area was main­tained by adding a short section (virtually a strake) outboard of the engine. These exten­sions had a sharp-edged trapezoidal profile. According to Tsybin These extensions, added on the recommendation of CAHI, did not pro­duce the desired effect and were omitted’, but they are shown in drawings. In fact, CAHI real­ly wanted a total rethink of the wing, as related in the final Tsybin entry. The tailplane was re­designed with only 65 per cent as much area, with sharp taper and a span of only 3.8m (12ft 5%in). Its power unit was relocated ahead of the pivot, requiring No 6 (trim) tank to be moved forward and shortened. The fin was likewise greatly reduced in height and given sharper taper, and pivoted two frames further aft. The ventral strake underfin was replaced by an external ventral trimming fuel pipe. The main landing gear was redesigned as a four – wheel bogie with 750 x 250mm tyres, and the outrigger gears were replaced by hydraulically extended skids in case a nacelle should touch the ground. The pilot was given a better view,
with a deeper canopy and a sharp V (instead of flat) windscreen. The camera bay was re­designed with a flat bottom with sliding doors. The nose was given an angle-of-attack sensor, and a pitot probe was added ahead of the fin. The drop tanks were increased in diameter to 700mm (2ft 31/2in) but reduced in length to 5.8m (19ft) instead of 11.4m (37ft 4Min). Not least, the D-21 engines never became available, and had to be replaced by plain afterburning turbojets. The choice fell on the mass-produced Tuman – skii R-l IF, each rated at 3,940kg (8,686Ib) dry and 5,750kg (12,676 Ib) with afterburner. These were installed in longer and slimmer nacelles, with inlet sliding centrebodies pointing straight ahead instead of angled downwards.

There is no reason to doubt that the pre-se­ries RSR, designated R-020, would have per­formed as advertised. It suffered from a Kremlin captivated by ICBMs and space, which took so much money that important aircraft programmes were abandoned. The United Kingdom similarly abandoned the Avro 730, a reconnaissance bomber using identical tech­nology, but in this case it was for the insane rea­son that missiles would somehow actually replace aircraft. Only the USA had the vision and resources to create an aircraft in this class, and by setting their sights even higher the Lockheed SR-71 proved valuable for 45 years.

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 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

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 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).