EF 1 2 6 / E F 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 of the year V3 and V5 had made 12 short flights, five of them 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 3째 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 flyingbomb 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. Arma-
ment 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.
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 EF131 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 of the wartime Ju 287, with considerable dihedral and a leading edge swept forward at 19째 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.
Dimensions (V5) Span Length (fuselage only) Wing area
6.65m 8.5m 7.8m 8.9 nf
21 ft 9% in 27 ft 10% in 25 ft 7 in 95.8ft2
Weights Empty Loaded
1,100kg 2,800 kg
2,425 Ib 6,173 Ib
780km/h 680 km/h
485 mph 423 mph
23min 45min
(186 miles) (2 17 miles)
Performance Maximum speed (clean) (external load) Range/endurance (full power) 300 km (60% power) 350 km
EF 131 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
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