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R.A.E.- Vickers Transonic Research Rocket
Artist's impression of the Miles M.52
Role	Experimental supersonic research craft
National origin	United Kingdom
Manufacturer	Royal Aircraft Establishment & Vickers-Armstrong
Status	Cancelled
Number built	3 complete craft
Developed from	<!—-Miles M.52 design -->

The Miles M.52 was a British supersonic research aircraft project which was undertaken in top secret between 1942 and 1945 to Ministry of Supply specification E.24/43. The project was cancelled because the Government of the day was persuaded that with the accumulation of data it was felt that the E.24/43 aircraft was unlikely to reach sonic speed. Wind-tunnel model tests apparently indicated serious loss of longitudinal stability at high subsonic speed as was then characteristic of existing aircraft. The decision was reached to acquire preliminary experience of flight under transonic conditions using rocket-driven pilotless scale models.The Ministry of Supply (MOS) formed the Guided Projectile Establishment under W. P. Cooke at Westcott, Buckinghamshire, and the Rocket Propulsion Group under A. D. Baxter at RAE, Farnborough. Work commenced in applying German technology, with the Halstead Experimental Centre of the MOS monitoring commercial exploitation.

Development

A contract was placed in 1945 with Vickers Armstrong Limited for the design and construction of several test vehicles. Early in 1946 the contract for the E.24/43 was cancelled, since it was felt impossible to ensure the safe escape for the pilot in the event of an emergency ejection at high speed. The difficulties surrounding flight at sonic speeds appeared to increase with increasing knowledge. In those circumstances consideration of an improved version of the E.24/43 was discarded in favour of pilotless models which for the initial try-out were to be 3/10-scale versions of the Miles M.52 design. For drag and stressing reasons the operational altitude had to be in the stratosphere to which altitude the test vehicles would be carried by a parent aircraft, a De havilland Mosquito

One of the Vickers models undergoing supersonic wind-tunnel testing at the Royal Aircraft Establishment (RAE) c.1943

Power plant

The design was to be powered by a 362 kg (800 lbs.) thrust hydrogen peroxide 'hot' motor evolved at Westcott with characteristics drawn from the Walter RI 2031209 ATO unit. This initiated the Beta and the subsequent Gamma MOS inspired engines. In October 1948 the Vickers Transonic model flew at 930 mph in level flight at 35,000 ft.

Design

The test vehicle was a 3/10-scale model of the Miles E.24/43 design except for the omission of the distinctive annular air intake of the full-scale aircraft. To maintain the center of gravity (c.g.) it was necessary to include a large balance weight (a!most 1/10th of total all-up weight) in the foremost section of the nose. The layout was further restricted by the need to maintain a constant c.g. position during the consumption of the fuels. This was achieved by placing ahead of the wing a small tank holding one-third of the total oxidant (as well as the fuel in the shaped nose tank) and locating the main oxidant tank aft of tile wing. Other large components were placed fore-and-aft of the wing. In the space below and above the wing centre section were located the air, fuel, oxidant and warm-air pipes, telemetering transmitter, instruments and batteries as well as the auto-pilot, timing clock, wiring terminal fuses and the connections by which the test vehicle was carried on the parent aircraft. The rear section housed the combustion chamber, radar transponder, smoke-producing fluid, instruments and oscillators for combustion chamber pressure and tailplane angle, servos and dive mechanism for the tailplane which together with the fixed directional fin were fitted to the lower body prior. The single-piece wing was of mahogany with Dural inserts at the leading and trailing edges; it was of biconvex section and of tapered plan form with an unswept half-chord line. The Dural inserts formed a convenient dipole-aerial system for the telemetering unit. (A similar arrangement on the tailplane served the radar transponder.)

Operational history

A1: On the last check flight before live firing the parent aircraft descended into a storm at 22,000 ft. When smooth conditions were regained at about 8,000 ft altitude the test vehicle A1 carrying all the prototype examples of instruments and equipment was found to have parted from the aircraft and disappeared beneath the waters of the Bristol Channel.
List of Test Vehicles in Chronological Order
Ref. Type Details
A1 Complete Lost in cloud during early flight trials--30/05/47
A2 Complete First release--rocket motor failed to ignite--08/10/47
A9 Fuselage Rocket motor starting tests. Released from 35,000 ft 29/02/48 fired
A8 Fuselage Rocket motor starting tests• Release from 35,000 if--29/02/48 non firing
A12 Fuselage Rocket motor starting tests. Release from 25,000 ft--ignition fired 05/03/48
All Fuselage Rocket motor starting tests. Release from 25,000 ft--ignition fired 07/06/48
A10 Fuselage Rocket motor starting tests. Release from 35,000 if--explosion in tail 09/06/48
A3 Complete Rocket motor starting tests. Release from 35,000 ft successful 09/10/48

Specifications

General characteristics Performance

See also

• Sound barrier

Aircraft of comparable role, configuration, and era

• Bell X-1
• Miles M.52

References

Notes

Bibliography

• Brown, Don Lambert. Miles Aircraft Since 1925. London: Putnam & Company Ltd., 1970. ISBN 0-37000-127-3.
• Brown, Eric. "Miles M.52: The Supersonic Dream." Air Enthusiast Thirteen, August-November 1980. ISSN 01443-5450.

External links

• Eric "Winkle" Brown talks about the M.52 in 2008
• Museum of Berkshire Aviation: "The M.52 Story"
• Article: The Aeroplane Spotter, 19th October 1946 "High Speed Research" (pdf download)

ircraft Begin

name = Miles M.52 image = Image:MilesM52 1.jpg caption = Artist's impression of the Miles M.52

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Role Experimental supersonic aircraft National origin United Kingdom Manufacturer Miles Aircraft Designer Don L. Brown Status Cancelled Number built 1

The Miles M.52 was a British supersonic research aircraft project which was undertaken in top secret between 1942 and 1945. The Air Ministry later cancelled the project for reasons that remain controversial to this day.

Design and development

The British Miles Aircraft company had its beginnings in the mid 1920s, making its name in the 1930s with affordable ranges of innovative light aircraft. They became best known perhaps for the Miles Magister and Miles Master trainers, large numbers of which were used by the the RAF for fighter pilot training. Miles had a good relationship with the Air Ministry and the Royal Aircraft Establishment (RAE), and had submitted several proposals for advanced aircraft in response to ministry specifications. Despite their low-technology mainstream products and lack of jet aircraft experience, on 8 October 1943 the Air Ministry and the Ministry of Supply assigned the company a top-secret contract, E.24/43, for a jet-powered research plane designed to reach supersonic speeds. The contract called for an "aeroplane capable of flying over 1,000 mph (1,600 km/h) in level flight, over twice the existing speed record, and climb to 36,000 feet (11,000 m) in 1.5 minutes." The specification was intended only to match the supposed performance of a German aircraft: the 1,000 mph (supersonic) requirement resulted from the mistranslation of an intercepted communication stating that the maximum speed was 1,000 km/h (subsonic). This report dealt with the Me 163A and/or the Me 262.

A huge number of advanced features were incorporated into the resulting M.52 design, many of which hint at a detailed knowledge of supersonic aerodynamics. With no other sources of such information Miles had turned to design data for stabilising projectiles. In particular, the design featured a conical nose and sharp wing leading edges, as it was known that round-nosed projectiles could not be stabilised at supersonic speeds. The design used very thin wings of biconvex section proposed by Jakob Ackeret for low drag. The wing tips were "clipped" to keep them clear of the conical shock wave generated by the nose of the aircraft. The fuselage had the minimum cross-section allowable around the centrifugal engine with fuel tanks in a saddle over the top.

Another critical addition was the use of an "all-moving tail", also known then as the "flying tail", a key to supersonic flight control which contrasted with traditional hinged tailplane (horizontal stabilizer) designs. Conventional control surfaces became ineffective at the high subsonic speeds then being achieved by fighters in dives, due to the aerodynamic forces caused by the formation of shockwaves at the hinge.

One of the Vickers models undergoing supersonic wind-tunnel testing at the Royal Aircraft Establishment (RAE) c.1943

The design was to be powered by Frank Whittle's latest engine, the Power Jets W.2/700. It incorporated a reheat jetpipe - now known as an afterburner - to give extra power. The burning of extra fuel in the tailpipe avoided overheating the metal of the turbine blades and made use of the unburnt oxygen in the exhaust. In order to supply more air to the afterburner than could move through the fairly small engine, a fan, powered by the engine, was installed in front of the assembly to blow air around the engine in ducts, making the W.2/700 essentially an early turbofan.

Finally the design included another critical element, the use of a shock cone in the nose to slow the incoming air to the subsonic speeds needed by the engine.

Supersonic heating was not completely understood at the time, so the M.52 was built using stainless steel ^{[citation required]} rather than the more common duraluminum.

The pilot would have sat in a small cockpit inside the shock cone in the nose of the aircraft, and in an emergency the entire area would be separated from the aircraft using explosive bolts. The pilot would then wait for the cockpit to slow, before exiting and parachuting to safety. The chances of the pilot exiting the capsule were of serious concern, since it was not stable on its own at supersonic speeds, and likely would have tumbled, possibly breaking up.

The M.52's design underwent many changes during development due to the uncertain nature of the task. The overseeing committee was concerned that the biconvex wing would not give sufficient altitude for testing the aircraft in a dive. The thin wing could have been made thicker if required, or a section added to increase the wing span. As the project progressed an increase in total weight led to concerns that power would be insufficient and rocket assistance or extra fuel tanks were considered, as was high altitude air-launching from a bomber.

The calculated landing speed of 160 mph (comparable with modern fighters but very high for that time) combined with the small undercarriage track was a concern, but had to be accepted.

Testing

A Miles M.3B Falcon Six light aircraft that had been used for wing tests by the RAE, was provided to Miles in 1943. A full size wooden model of the M.52 wing, test instrumentation, and a different undercarriage were fitted. Owing to the wing's thinness and sharp leading and trailing edges, the aircraft was nicknamed the "Gillette Falcon". It was first flown on 11 August 1944. Compared with a standard Falcon Six, wing area was reduced by about 12%, but landing speed was increased by over 50% from 40 mph to 61 mph.

For high speed testing, the flying tail was fitted to the fastest aircraft available, a Supermarine Spitfire. RAE test pilot Eric Brown stated that he tested this successfully during October and November 1944, attaining Mach 0.86 in a dive. The flying tail was also fitted to the "Gillette Falcon", low speed tests being flown at the RAE in April 1945.

Operational history

Prototypes

In 1944, design work was considered 90% complete and Miles was told to go ahead with the construction of three prototype M.52s. Later that year, the Air Ministry signed an agreement with the United States to exchange high-speed research and data. Miles Chief Aerodynamicist Dennis Bancroft stated that the Bell Aircraft company was given access to the drawings and research on the M.52, but the U.S. reneged on the agreement and no data was forthcoming in return. Unknown to Miles, Bell had already started construction of a rocket-powered supersonic design of their own, but were battling the problem of control. A variable-incidence tail appeared to be the most promising solution; the Miles and RAE tests supported this. Later, under manned flight, pilot Chuck Yeager would verify it experimentally, and all subsequent supersonic aircraft would either have an all-moving tailplane or a delta wing.

Cancellation

By February 1946, the new Labour government introduced dramatic budget cuts. The Director of Scientific Research, Sir Ben Lockspeiser subsequently cancelled the project. Other factors contributing to the cancellation included doubts about pilot safety, as well as some German research that seemed to point to swept wings being desirable at supersonic speeds.

At cancellation, the first of the three M.52s was 82% completed, with test flights planned to begin in a few months. The test programme involved the progressive testing and development of the M.52 and its engine by the RAE, with the aim of achieving Mach 1.07 by the end of 1946.

Miles became bankrupt in 1947 and assets including the design data for the M.52 were acquired by Handley Page.

Subsequent work

Several thousand pounds would have been required to complete the first M.52. Instead, the government instituted a new programme involving expendable, pilotless, rocket-propelled missiles. The design was passed to Barnes Wallis at Vickers Armstrong, and the engine development took place at the RAE. The result was a 30% scale radio-controlled model of the original M.52 design, powered by an Armstrong Siddeley Beta rocket engine.

The first launch took place on 8 October 1947 at high altitude from a DH Mosquito, but the rocket exploded shortly after release. Only days later, the Bell X-1 broke the sound barrier. There was a flurry of denunciation of Labour's decision to cancel the project, with the Daily Express taking up the cause for the restoration of the M.52 programme, to no effect. On 10 October 1948, a second rocket was launched, and a speed of Mach 1.38 was obtained. Instead of diving into the sea as planned, the model failed to respond to radio commands and was last observed (on radar) heading out into the Atlantic. At that point, further work was cancelled.

Many early jet aircraft had round noses, thick wings and hinged elevators, giving them critical mach numbers well below the speed of sound, and were less suitable for research into high subsonic speeds (in dives) than the Spitfire with its thinner wings.

Many important design principles incorporated in the M.52 did not reappear until the mid- to late 1950s, with the development of truly supersonic aircraft such as the Fairey Delta 2 and English Electric P.1.

Specifications (M.52)

Data from

General characteristics

• Crew: 1

Performance

See also

• Sound barrier

Aircraft of comparable role, configuration, and era

• Bell X-1
• Silbervogel

References

Notes

Bibliography

• Amos, Peter and Don Lambert Brown. Miles Aircraft Since 1925, Volume 1. London: Putnam Aeronautical, 2000. ISBN 0-85177-787-0.
• Brown, Don Lambert. Miles Aircraft Since 1925. London: Putnam & Company Ltd., 1970. ISBN 0-37000-127-3.
• Brown, Eric. "Miles M.52: The Supersonic Dream." Air Enthusiast Thirteen, August-November 1980. ISSN 01443-5450.
• Brown, Eric. Wings on my Sleeve. London: Weidenfeld & Nicolson, 2006. ISBN 978-0297845652.
• Faster than Sound. NOVA (PBS) documentary, first broadcast 14 October 1997.
• McDonnell, Patrick. "Beaten to the Barrier." Aeroplane Monthly Volume 26, No. 1, Issue 297, January 1998.
• Pisano, Dominick A., R. Robert van der Linden and Frank H. Winter. Chuck Yeager and the Bell X-1: Breaking the Sound Barrier. Washington, DC: Smithsonian National Air and Space Museum (in association with Abrams, New York), 2006. ISBN 0-8109-5535-0.
• Wood, Derek. Project Cancelled. Indianapolis: The Bobbs-Merrill Company Inc., 1975. ISBN 0-672-52166-0.
• Yeager, Chuck et al. The Quest for Mach One: A First-Person Account of Breaking the Sound Barrier. New York: Penguin Studio, 1997. ISBN 0-670-87460-4.

External links

• Faster than Sound - Nova documentary
• transcript of the Nova programme
• Jets45 Histories
• Eric "Winkle" Brown talks about the M.52 in 2008
• Museum of Berkshire Aviation: "The M.52 Story"
• Article: The Aeroplane Spotter, 19 October 1946 "High Speed Research" (pdf download)