Category Soviet x-plenes

Rafaelyants Turbolyot

Подпись: Turbolyot

Purpose: To evaluate a wingless jet VTOL aircraft.

Design Bureau: Aram Nazarovich Rafaelyants, chief engineer of GVF (civil air fleet) repair and modification shops at Bykovo.

Rafaelyants was working at Bykovo, on the Volga, in 1929-59. He had previously pro­duced two lightplanes, flying his RAF-2 to Berlin in 1927. In 1941 his RAF-1 Ibis transport nearly went into production. He worked on many aircraft, and after 1945 handled pro­jects concerned with jet engines and their testing. The Rolls-Royce Thrust Measuring Rig (‘Flying Bedstead’) of 1953 inspired him to produce the Turbolyot. This was flown teth­ered to a gantry in early 1957, and was pub­licly demonstrated in free flight in October of that year. Nearly all the flying was done by he­licopter test pilot Yu A Garnayev. Because of its historical interest, the Turbolyot is today stored in the WS museum at Monino, al­though it was not a WS aircraft but a civilian flying test rig.

The engine selected was the Lyul’ka AL-9G, a single-shaft turbojet rated at 6,500kg (14,330 Ib). This was mounted vertically in the centre of a cruciform framework of welded steel tube. The engine had special bearings
and lubrication, and was fitted with a high – capacity bleed collector ring. On each side was a fuel tank, with fuel drawn equally from both. In front was the enclosed pilot cab, with a door on the right. The bleed system served four pipes, one to each extremity of the vehi­cle, where downward – and upward-pointing nozzles were provided with a modulating valve under the management of the pilot’s control column. The same system also oper­
ated rods and levers governing a two-axis tilt­ing deflector ring under the engine nozzle. Each of the four main structural girders was provided with a long-stroke vertical landing leg with a castoring wheel.

This device never crashed, and provided a solid background of data for the Yak-36 and subsequent jet-lift aircraft.

Grokhovskii G -31, Y akob Alksnis, Strekoza

Purpose: To build a troop-carrying glider; this was later modified into powered aircraft.

Design Bureau: WS-RKKA (Red Army special design team for aviation forces), director Pavel Ignatyevich Grokhovskii (1899-1946).

Grokhovskii had a brief but intense career, forming a branch of WS-RKKA in Leningrad in 1934 and seeing it liquidated in 1936. Most of his designs were concerned with as­sault by airborne forces, and all showed a re­markable originality. The G-61 was a ‘people pod’ able to house seven armed troops and actually flown attached under each wing of an R-5, a mass-produced 700hp biplane. The G-31 (in some documents called G-63i>/s), named for WS Gen Yakob Alksnis, was a giant cargo glider, designed by Grokhovskii and B D Urlapov to carry troops lying inside the wing. From this Grokhovskii produced the G-31 powered aircraft. First flown in late 1935, it flew to Moscow in 1936 for RKKA test­ing. It was eventually decided that the
arrangement of troops packed inside the wing, with no chance of escape in flight, was unacceptable. In any case, the concept of a powered glider for assault operations was eventually considered unsound.

Sharing a strengthened version of almost the same airframe as the glider, the G-31 (again named for Alksnis and also dubbed Strekoza, dragonfly) was a graceful aircraft as befits a powered version of a glider. Though intended for military purposes it was one of several types designed in the 1930s with no consideration of speed, because this was not thought significant. The airframe was wooden, with a vestigial fuselage of multiply veneer formed by presses with double curva­ture. On the front was a puny 100hp M-l 1 five – cylinder radial. Subsequently Grokhovskii built a G-31 with a strengthened structure matched to the 700hp M-25, an imported (later licensed) Wright R-1820 Cyclone. This was fitted in a Townend-ring cowl and it drove a Hamilton light-alloy ground-ad­justable propeller. It is believed that later a three-blade flight-variable Hamilton Standard
was fitted. As in the glider there were cockpits for a pilot and flight engineer, while between the wing ribs were compartments for 18 troops, nine in each wing (drawings show eight in each wing). They boarded and were extracted through hinged leading edges, which were transparent, as in the G-61 pods.

Few details of the G-31 have survived. Clearly the naming of this aircraft and its predecessor after Alksnis was a mistake, because he was arrested in 1936 and execut­ed in 1938. The close-knit Grokhovskii team was ‘liquidated’ very soon after the General’s arrest.

Grokhovskii G -31, Y akob Alksnis, Strekoza

Dimensions (M-25 engine)

Span

Length

Wing area

28.0m

13.9m

70.5m2

91 ft M in 45 ft 7n in 759 11!

Weights

Empty

1,400kg

3,086 Ib

Loaded

3,200kg

7,055 Ib

Performance Maximum and cruising speed limited to

135km/h

84 mph

No other data.

 

Left: G-31 with M-25 engine.

Below left: G-31 glider.

 

Below right: G-31 with M-l 1 engine.

Grokhovskii G -31, Y akob Alksnis, Strekoza

 

Grokhovskii G -31, Y akob Alksnis, Strekoza

Grokhovskii G -31, Y akob Alksnis, Strekoza

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

In 1960 the Ye-6T/l, the first true series-built MiG-21, callsign Red-31, was rebuilt for record purposes, with various modifications. In order not to reveal too much to the FAI in­ternational body, it was given the invented designation Ye-66A. The most obvious change was to attach a rocket package un­derneath the fuselage. The rocket engine was designated S-3/20M5A, the ultimate version of Dushkin’s family burning kerosene and RFNA fed by peroxide turbopumps. The propellants were packaged with the engine and control system in a large gondola designated U-21. Thrust was 3,000kg (6,614 Ib) at sea level, ris­ing to about 3,700kg (8,150 Ib) at high altitude. The rocket nozzle was angled 8° downwards, but despite this it was necessary to replace the usual MiG-21 underfin by two shorter but deeper ventral fins each inclined outwards. The main engine was replaced by an R-l 1F2- 300, with a maximum afterburning rating of 6,120kg (13,492 Ib); this engine later became standard on the MiG-21 PF. Other modifica­tions included 170 litres (37.4 Imperial gal­lons) of extra kerosene fuel in a spine fairing behind the canopy, and a fin extended for­wards to increase area of the vertical tail to 4.44m2 (47.7ft2). The Ye-66A did not set any ratified speed records, but on 28th April 1961 it was flown by G K Mosolov in a zoom to a new world absolute height record of 34,714m (113,891ft). He made a low flypast with rock­et in operation at the airshow at Moscow Tushino on Aviation Day (9th July) 1961.

. Sukhoi 100LDU

Purpose: To flight-test canard surfaces. Design Bureau: P O Sukhoi, Moscow

As explained in the history of the T-4, this enormous project required back-up research right across Soviet industry. The Sukhoi OKB
itself took on the task of investigating the proposed canard surfaces. As the only vehicle immediately available was a two-seat Su-7U, with a maximum Mach number of 2 instead of 3, the resulting aircraft – with designation 100LDU – ceased to be directly relevant to the

T-4 and became instead a general canard research vehicle. It was assigned to LIl-MAP test pilot (and future Cosmonaut) Igor Volk, and was tested in 1968-71.

The basic Su-7U, powered by an AL-7FI – 200 with a maximum afterburning rating of 10,100kg (22,282 Ib), was subjected to minor modifications to the rudder and braking- parachute installation, and was fitted with fully powered canard surfaces on each side of the nose. These were of cropped delta shape, with a greater span and area than those of contemporary experimental MiG aircraft, and with anti-flutter rods which were longer and nearer to the tips.

This aircraft fulfilled all test objectives, though the numerical data were of only marginal assistance to the T-4/100 design team.

SLIKHOI 02-10, OR L02-10

. Sukhoi 100LDU

Purpose: To investigate direct side-force control.

Design Bureau: P O Sukhoi, Moscow.

In 1969 this Su-9 was modified for the LII, which wished to investigate the application of direct side force. The LII had been concerned at American research into direct lateral or ver­tical force which could enable a fighter to rise, fall, move left or move right without changing the aircraft’s attitude. In other words such an aircraft could keep pointing at a target in front while it crabbed sideways (for example). Testing began in 1972. In 1977 the aircraft was returned to a Sukhoi OKB factory and had the upper nose fin removed, testing continuing as a joint LII/Su programme. It was further modified in 1979.

Originally this aircraft was a production Su – 9 interceptor, though it never saw active ser­vice. In its first 02-10 form is had substantial vertical fins added above and below the nose. Each fin was pivoted at mid-chord and fully
powered. The pilot was able to cut the nose fins out of his flight-control circuit, leaving them fixed at zero incidence. When they were activated, movement of his pedals drove the fins in unison with each other and in unison with the rudder. The two canard fins moved parallel to the rudder, to cause the aircraft to crab sideways. Each surface was of cropped delta shape, with a lower aspect ratio than the horizontal canards of the S-22PDS. Compared with the lower fin the upper surface had significantly greater height, and it was mounted slightly further forward. Each was fitted with an anti-flutter rod mass,
which during the course of the programme was moved from 40 per cent offin height (dis­tance from root to tip) to 70 per cent. After the 02-10’s first series of tests the upper nose fin was removed (leaving its mounting spigot still in place). Later a cine camera was installed on the fin to record lateral tracking across the ground, and in some of the later tests the wings were fitted with smoke nozzles along the leading edge, to produce visible stream­lines photographed by a camera in a box im­mediately ahead of the radio antenna.

This aircraft generated useful information, but the idea has never been put into practice.

Three different versions of L02-10 test-bed.

. Sukhoi 100LDU

 

Bereznyak-Isayev BI

Bereznyak-Isayev BI

Purpose: Experimental rocket-engined interceptor-fighter.

Design Bureau: Designers Aleksandr Yakovlevich Bereznyak and Aleksei Mikhailovich Isayev, working at OKB of Bolkhovitinov, later managed by CAHI (TsAGI).

In 1939 Bereznyak was an observer at the sta­tic tests of the first reliable rocket engine de­veloped by Leonid Stepanovich Dushkin. In early 1940 he watched flight tests of the prim­itive RP-318 (see later under Korolyev). He discussed rocket aircraft with Isayev, who had been a Dushkin engineer involved with the RP-318. In late May 1941 they decided to propose a high-speed rocket-engined fighter. They put the suggestion to Prof Bolkhovitinov (see later entry). After discussion with all in­terested parties Bolkhovitinov sent a letter to GUAP (chief administration ofaviation indus­try) on 9th July 1941 putting forward a de­tailed proposal. Soon a reply came from the Kremlin. The principals were called to GUAP before Shakhurin and A S Yakovlev, and with­in a week there was a full go-ahead. The order was for five prototypes, with the time to first flight cut from the suggested three months to a mere 35 days.

A complete Bolkhovitinov team were con­fined to the OKB for 40 days, working three shifts round the clock. Tunnel testing was
done at CAHI, supervised by G S Byushgens. The first (unpowered) flight article was built without many drawings, dimensions being drawn directly on the materials and on tem­plates. B M Kudrin made the first flight on 10 th September 1941, the tug being a Pe-2. All necessary data were obtained in 15 flights. On 16th October the OKB and factory was evac­uated to a half-built shed outside Sverdlovsk. The first (experimental) D-1A engine was in­stalled in late January 1942, but exploded dur­ing testing on 20th February, injuring Kudrin (sent to hospital in Moscow) and a techni­cian. The replacement pilot was Capt G Ya Bakhshivandzhi. He was in the cockpit on the first tied-down firing on 27th April 1942. On 15th May 1942 he made the world’s first flight of a fully engineered rocket interceptor, still fitted with skis.

By March 1943 seven BI prototypes had been constructed, but the flying was entirely in towed or gliding flight because of serious problems caused by explosions and acid spillages. Powered flying did not resume until February 1943. By this time Kudrin had re­turned to flight status, and was assigned one of the Bis. On powered flight No 6 on 21st March 1943 a height of 3km (9,843ft) was reached in 30 seconds. On powered flight No7, with aircraft No 3, on 27th March, Bakhshivandzhi made a run at sustained full power; the aircraft suddenly pitched over and

dived into the ground. Tunnel testing later showed that at about 900km/h the BI would develop a nose-down pitching moment which could not be held by the pilot.

Dimensions

Span

Nosland2

6.48m

21 ft 3 in

Nos 3 and later

6.6 m

21 ft 8 in

Length

Nos 1 and 2

6.4 m

21ft

Nos 3 and later

6.935 m

22 ft 9 in

Wing area

Nos land 2

7.0m2

75.3ft2

No 3

7.2m2

77.5ft2

Weights

Empty

Nol

462 kg

1,019 Ib

No 3

790kg

1,742Ib

No 7

805kg

l,7751b

Loaded

No 3

1,650kg

3,638 Ib

No 7

1,683kg

3,710 Ib

Performance

Maximum speed

original estimate

800 km/h

497 mph

achieved

900 km/h

559 mph

1943 high-altitude estimate, not attempted

1,020 km/h

634 mph

Time to accelerate from 800 to 900 km/h

20 seconds

Take-off run

400m

1,310ft

Initial climb

120m/s

23,622 ft/min

Time to 5,000 m

50 seconds

16,404ft

Endurance under full power

2 min

Landing speed

143 km/h

89 mph

Bereznyak-Isayev BIПодпись: Top: BI No 1. Centre: Bakhchivandzhi with BI No 2. Bottom: BI No 6/PVRD in tunnel. This terminated the delayed plan to build a production series of 50 slightly improved air­craft, but testing of the prototypes continued. Until the end of the War these tested various later Dushkin engines, some with large thrust chambers for take-off and combat and small chambers to prolong the very short cruise en­durance (which was the factor resulting in progressive waning of interest). Other testing attempted to perfect a sealed pressurized cockpit. To extend duration significantly BI No 6 was fitted with a Merkulov DM-4 ramjet on each wingtip. These were fired during test in the CAHI T-101 wind tunnel, but not in flight.

By 1944 the urgency had departed from the programme, and the remaining BI Nol (some were scrapped following acid corrosion) were used as basic research aircraft. BI No7 was modified with revised wing-root fairings and stronger engine cowl panels, but at high speed tailplane flutter was experienced. BI No 5s (on skis) and BI No 6 (on wheels) were modified and subjected to investigative glid­ing tests, initially towed by a B-25J.

In 1948 Bereznyak proposed a mixed – power interceptor with a three-chamber rocket engine of 10,000kg (22,046 Ib) sea – level thrust, for ‘dash’ performance, and a Mikulin AM-5 turbojet of 1,900kg (4,1891b) sea-level thrust. Estimated maximum speed was Mach 1.8, and range 750km (466 miles). This was not proceeded with.

The BI Nol had a small and outstandingly simple all-wood airframe. The straight-ta­pered wing, 6 per cent thick, had two box spars and multiple stringers supporting skin mainly of 2mm ply. Outboard were fabric – covered ailerons. Inboard were split flaps with light-alloy structure (the only major metal parts), with a landing angle of 50°. The fuselage was a plywood monocoque with fabric bonded over the outer surface. It was constructed integral with the upper and lower fins. The rudder and elevators were fabric-covered. On the tailplane were added small circular endplate fins, and the powered aircraft had the tailplane braced to both the upper and lower fins.

The engine bay was lined with refractory materials and stainless steel. The standard engine was the Dushkin D-1A-1100, the des­ignation reflecting the sea-level thrust (2,425 Ib), rising to about 1,300kg (2,866 Ib) at high altitude. The propellants, fed by com­pressed air, were RFNA (red fuming nitric acid) and kerosene. These were contained in cylindrical stainless-steel tanks in the centre fuselage. The pneumatic system not only fed the propellants but also charged the guns and operated the flaps and main landing gears. The latter retracted inwards into the wings and normally had wheels with 500 x 150 tyres. Under the ventral fin was a retracting tail-
wheel. In winter these units were replaced by skis, the main skis retracting to lie snugly under the wings.

The cockpit had a simple aft-sliding canopy, and a bulletproof windscreen. Cer­tain of the prototypes had armament, com­prising two ShVAK 20mm cannon, each with 45 rounds, fired electrically and installed in
the upper half of the nose under a cover se­cured by three latches on each side. Between the spars under the propellant cylinders was a bay which in some aircraft could house a small bomb load (see below). Structural fac­tor of safety was 9, rising to no less than 13.5 after using most of the propellants.

By any yardstick the BI No 1 was a remark­
able achievement, and all pilots who flew it thought it handled beautifully. It was killed by the time it took to overcome the problems, and – crucially – by the impracticably short flight endurance.

The nominal weight breakdown for a fully equipped powered aircraft was:

Airframe

462kg

1,018.5 Ib

Comprising fuselage

182kg

401 Ib

Wing

174kg

383.6 Ib

Tail group

30kg

66 Ib

Landing gear, wheeled

60kg

1321b

Engine

48kg

106 Ib

Controls

16kg

35 Ib

RFNA tanks

80kg

176.4lb

Kerosene tanks

31.2kg

68.8 Ib

Airbottles

22.4kg

49.4 Ib

Guns

84kg

185 Ib

Armour

76 k»

167.5lb

Armour glass, windscreen

6kg

13 Ib

Other equipment about

20kg

44 Ib

Useful load comprised

Pilot

90kg

198 Ib

Nitric acid

570kg

1,256.6 Ib

Kerosene

135kg

297.6 Ib

20mm ammunition

19.6kg

43.2 Ib

Bombs

38.4 kg

84.6 Ib

Bereznyak-Isayev BI

ri

!

OKB drawing of BI No 6/PVRD.

Korolyov RP-318-1

Purpose: To test a liquid-propellant rocket engine in flight.

Design Bureau: RNII, rocket-engine scientific research institute; head ofwinged-aircraft department Sergei Pavlovich Korolyov.

Korolyov was a pioneer of light aircraft and, especially, high-performance gliders before, in early 1930s, concentrating on rocketry. In

1934 he schemed the RP-218, a high-altitude rocket aircraft with a two-seat pressure cabin and spatted main landing gear. The engines were eventually to have comprised three RD – 1, derived from the ORM-65 (see below), and in a later form the structure was refined and the landing gear made retractable. The RP – 218 was never completed, partly because Ko­rolyov was assigned to assist development of the BICh-11 (see under Cheranovskii). In

1935 he produced his SK-9 two-seat glider, and suggested that this could be a useful rocket test-bed. In 1936, in his absence on other projects, A Ya Shcherbakov and A V Pallo began converting this glider as the flight test-bed for the ORM-65. This was fired 20 times on the bench and nine times in Ko­rolyov’s RP-212 cruise missile before being in­stalled in the RP-318 and fired on the ground from 16th December 1937. The ORM-65 was
then replaced by the RDA-I-150 Nol, cleared to propel a manned aircraft. This engine was repeatedly tested on the ground, and then flew (without being fired) in four towed flights in October 1939. After further tests the RP-318 was towed off on 28th February 1940 by an R-5 flown by Fikson, with Shcherbakov and Pallo as passengers in the R-5. The SK-9 was released at 2,800m, and then glided down to 2,600m where pilot Vladimir Pavlovich Fedorov fired the rocket. The SK-9 accelerated from 80 to 140km/h on the level and then climbed to 2,900m, the engine stop­ping after 110 seconds. Fedorov finally landed on a designated spot. Shavrov: This flight was of great significance for Russia’s rocket en­gines’. Much later Korolyov became the ar­chitect of the vast Soviet space programme.

The RP-318-1 was based on the SK-9, a shapely sailplane of mainly wooden con­struction. The rear seat was replaced by a ver­tical Dl light-alloy tank for 10kg (22 Ib) of kerosene, and immediately behind this were two vertical stainless-steel tanks projecting up between the wing spars each holding 20kg (441b)of RFNA (red fuming nitric acid). The rocket engine and its pressurized gas feed and complex control system were installed in the rear fuselage, the thrust chamber being
beneath the slightly modified rudder. The RDA-I-150 was a refined version of the ORM – 65, designed jointly by V P Glushko and L S Dushkin. Design thrust was 70 to 140kg at sea level, the figure actually achieved being about 100kg (220.5 Ib). An additional ski was added under the fuselage.

This modest programme appears to have had a major influence on the development of Soviet rocket aircraft.

Dimensions Span Length Wing area

17.0m

7.44m

22.0m2

55 ft 914 in 24 ft 5 in 237ft2

Weights

Empty

570kg

l,2571b

Propellants

75kg

1651b

Loaded

700kg

1, 54315

Performance

Restricted by airframe to

165km/h

102.5 mph

Three-view of unbuilt

Korolyov RP-318-1

 

Korolyov RP-318-1

Nikitin PSN

Original 1936 version of PSN (lower side view, 1938 PSN-1).

Nikitin PSN

 

Подпись: Two PSNs afloat.

Purpose: A series of air-launched experimental gliders intended to lead to air – to-surface missiles.

Design Bureau: Initially OKB-21, later OKB – 30, chief designer N G Mikhel’son, later VV Nikitin.

In 1933 S F Valk proposed the development of a pilotless air-launched glider with an au­topilot, infra-red homing guidance and large warhead for use as a weapon against ships, or other major heat-emitting targets. From 1935 this was developed in four versions which in 1937 were combined into the PSN (from the Russian abbreviation for glider for special purposes). At this stage chief designer was Mikhel’son (see previous entry on MP). The concept was gradually refined into the P SN -1, of which a succession of ten prototypes were launched from early 1937 from under the wings of a TB-3 heavy bomber. By 1939 the to­tally different PSN-2 was also on test. Also designated TOS, these were initially dropped from the TB-3 and later towed behind a TB-7 and possibly other aircraft. In each case the glider was to home on its target at high speed after release from high altitude.

The PSN-1 was a small flying boat, with sta­bilizing floats under the high-mounted wing.

It had a cockpit in the nose, where in the planned series version the warhead would be. In the DPT version the payload was a 533mm (1ft 9in) torpedo hung underneath. Once the basic air vehicle had been perfect­ed the main purpose of flight testing was to develop the Kvant (quantum) infra-red guid­ance. In contrast the PSN-2 was a twin-float seaplane with a slim fuselage, low wing and a large fin at the rear of each float. This again was flown by human pilots to develop Kvant guidance. After release from the parent air­craft the manned gliders made simulated at­
tacks on targets before turning away to alight on the sea. The planned pilotless missiles were intended to be expendable, and thus had no need for provisions for alighting.

Neither ofthe PSN versions made it to pro­duction, these projects being stopped on 19th July 1940. In retrospect they appear to have been potentially formidable.

PSN-1

Span

Weight empty Payload

8.0m 970kg 1 tonne

26 ft 3 in 2,1381b 2,205 Ib

PSN-2

Span

7.0m

22 ft UK in

Length

7.98m

26 ft 2% in

Design mission of pilotless

version 40 km (25 miles) at 700 km/h

435 mph

Подпись: Left: PSN-1, with bomblet container, under wing of TB-3. Bottom: PSN-2 without payload. Nikitin PSN

Nikitin PSNNikitin PSN

Tupolev Tu-16 Experimental Versions

Tupolev Tu-16 Experimental Versions

Purpose: To use Tu-16 aircraft for various experimental purposes, and to take the basic design further.

Design Bureau: OKB-156 ofA N Tupolev, Moscow.

This graceful twin-jet bomber sustained what was in financial terms the most important programme in the entire history of the Tupolev design bureau up to that time. Since then, because of inflation, the Tu-154 and Tu-22/Tu-22M have rivalled it, though they were produced in smaller numbers. The pro­totype Tu-16, the Type 88, was a marriage of upgraded B-29 technology in structures, sys­tems and to some degree in avionics, with to­tally new swept-wing aerodynamics and what were in the early 1950s super-power tur­bojet engines. The Tu-16 entered production in 1953 powered by Zubets (Mikulin KB) RD-3M engines of 8,200kg (18,078 Ib) thrust. The second series block had the RD-3M-200 of8,700kg (19,180 Ib) followed by the 9,500kg (20,944 Ib) RD-3M-500, which was then retro­fitted to most earlier aircraft.

From 1953 the basic aircraft was repeated­ly examined against alternatives based as far as possible on the same airframe but using different propulsion systems. Most of the studies had four engines. Tupolev had origi­nally schemed the 88 around two Lyul’ka AL-5 turbojets, but the design grew in weight to match the big AM-3 engine, and this was the key to its win over the smaller Ilyushin with the Lyul’ka engines. In parallel with the
production aircraft one project team led by Dmitri S Markov studied versions of the 88 with not two but four AL-5 engines, and then four of the more powerful (typically 14,330 Ib, 6,500kg) AL-7 engines. These Type 90s would have been excellent bombers, with in­creased power and much better engine-out performance, but the decision was taken not to disrupt production. On the other hand, vir­tually the same inboard wing and engine in­stallation was then used in the Tu-110 transport, two of which were built using the Tu-104 as a basis. Some of the four-engined bomber studies had engines in external na­celles hung on underwing pylons.

From 1954 Type 88 prototypes and a wide range of production Tu-16s were used over a period exceeding 40 years as experimental aircraft. Some carried out pioneer trials in aer­ial refuelling at jet speeds.

One large group of about 20 aircraft was kept busy in the development of avionics, in­cluding navigation, bombing and cartograph­ic guidance, parent control of drones and targets, and the direction of self-defence gun­nery systems.

Probably the most important single duty of Tu-16LL (flying laboratory) aircraft was to air – test new types of turboj et and turbofan engine. In each case the engine on test would be mounted in a nacelle either carried inside the weapon bay or, more often, recessed into it. Usually the test engine would be suspended on vertical hydraulic jacks or a large pivoted beam so that in flight it could be extended
down fully into the airstream, with its efflux well clear of the rear fuselage. In many cases the engine pod or the Tu-16 fuselage ahead of it would be fitted with a fairing or door which could be left behind or opened as the pod was extended for test. Among the engines air-tested under Tu-16LL aircraft were: the Ivchenko (later Progress) AI-25, Lyul’ka AL-7F – 1, AL-7F-2, AL-7F-4 and AL-31F, Solov’yov (Avi – advigatel) D-30, D-30K, D-30KP and D-30F6 (in MiG-31 installation), Lotarev (Ivchenko Progress) D-36, Kuznetsov NK-6 (with and without afterburner) and NK-8-2, Tumanskii (Soyuz)R-l 1 AF-300( Yak-28nacelle)andR-15- 300 (in the Ye-150 and the totally different MiG – 25installation), MetskhvarishviliR-2I-300and R-21F with Ye-8 inlet, Khachaturov R-27 ver­sions (including the vectored R-27V-300 in a complete Yak-36M prototype fuselage, Mikulin (Soyuz) RD-3M (many versions), Kolesov (RKBM) RD-36-41 and RD-36-51, and Dobrynin (RKBM) VD-7, VD-7M and VD-19 (in a pro­posed Tu-128 installation), etc.

One Tu-16 had its entire nose replaced by that intended for the Myasishchev M-55, in order to test the comprehensive suite of sen­sors. Another tested a scaled version of the bogie main landing gear for the Myasishchev M-4 and 3M strategic bombers, replacing the normal nose landing gear. A new twin-wheel truck was added at the tail. According to doc­uments a Tu-16 with outer wings removed tested the complete powerplant of the Yak-38 (presumably in free hovering flight) though photographs have not been discovered.

Purpose: To investigate the use of cryogenic fuels.

Design Bureau: ANTKA N Tupolev,

Moscow. Technical Director Valery Solozobov, cryogenic fuels ChiefDesigner Vladimir Andreyev.

For many years the USSR and its successor states have been replacing petroleum by nat­ural gas, which in 1999 provides over 53 per cent of the total of all Russia’s energy sup­plies. Since 1982 what is today ANTK Tupolev has been investigating the use of natural gas and also hydrogen as fuels for aircraft, because of their availability and clean burn­ing qualities. However, for use in vehicles both have to be liquefied by being cooled to exceedingly low temperatures. Liquid hydro­gen (LH2) boils at -255°C, an unimaginably low temperature at which (for example) all conventional lubricating oils are rock-solid. Moreover, this fuel is very expensive, and haz­ardous from the viewpoints of detonation and fire. On the other hand, liquefied natural gas (LNG) is widely available, at least threefold cheaper in Russia than aviation kerosenes, and also significantly improves flight perfor­mance. It is straightforward to store and han-

Below: Tu-155.

Photographs on the following page:

die, and less fire/explosion hazardous even than today’s kerosenes. After years of labora­tory work an existing civil transport was se­lected for use as an LNG flight test-bed. It has been flying since 1988. All work is now di­rected at the Tu-156, the first LNG aircraft de­signed to go into service.

T o flight-test an LNG sy stemANTKTupolev bailed back a Tu-154, No 85035, and replaced the No 3 (starboard) engine with an NK-88, fed with LNG by a completely separate fuel system. The NK-88 is a derivative of the Kuznetsov NK-8-2 turbofan (still fitted in the Nos 1 and 2 positions), with thrust unchanged at 20,945 Ib (9,500kg). The successor to Kuznetsov’s bureau is Samara/Trud. The complex feed system is shown in a drawing. The main tank, of 10ft 2in (3.1m) diameter and 17ft 81/2in (5.4m) long, is of AMG6 alu­minium alloy, with a 50mm (2in) lagging of foamed polyurethane. The NK-88 engine has a dedicated two-stage centrifugal pump dri­ven by a bleed-air turbine. LNG comes in at -152°C and is passed through a heat ex­
changer to convert it to gas. The engine com­bustion chamber is able to accept either this supply of NG or, on command, to switch to the kerosene supply normally used for the other engines. Work is still underway on a low-emissions chamber which will be used on the improved NK-89 engine to be fitted to the Tu-156. The definitive Tu-156 is expected to have the fuel in giant saddle tanks along the top of the fuselage. Instead, to reduce time and cost, at least the first Tu-156 has a main tank (capacity 28,6601b, 13 tonnes) behind the passenger cabin and, to preserve centre of gravity position, an auxiliary tank (8,377 Ib, 3,800kg) in the forward underfloor baggage hold. This reduces payload from 18 tonnes to 14 (30,864 Ib). Range will be 1,616 miles (2,600km) on LNG only, or 2,051 miles (3,300km) on combined LNG and kerosene.

Подпись: 6: Hermetically sealed fuel cabin 7: Auxiliary drain/vent 8: Main drain/vent 9: Main control complex. 10: Nitrogen bottles Подпись:Подпись:Tupolev Tu-16 Experimental VersionsEventually the Earth’s store of petroleum will run dry. It is pointless to say ‘More keeps being discovered’. The world’s aircraft will then have no alternative but to switch to an­other fuel, and LNG is the obvious choice.

Left: Tu-155 interior.

Right. Model of Tu-156.

Tupolev Tu-16 Experimental Versions

 

Tupolev Tu-16 Experimental Versions