Rolls-Royce Thrust Measuring Rig
| Rolls-Royce Thrust Measuring Rig | |
|---|---|
|
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| Type: | Experimental airplane |
| Design country: | |
| Manufacturer: | |
| First flight: |
July 3, 1953 (tied) |
| Production time: |
1953 |
| Number of pieces: |
2 |
The Rolls-Royce Thrust Measuring Rig (TMR) (German: Schubmessgestell ) was an experimental VTOL aircraft from the 1950s to research the use of jet engines for vertical takeoff and landing and the use of this technology in a supersonic aircraft. In the contemporary press, the suspension frame was because of its unusual appearance as Flying Bedstead (German: Flying bedstead ), respectively.
history
The planned supersonic VTOL aircraft would have installed a number of vertically installed jet engines for vertical take-off and hovering until the wings could develop sufficient aerodynamic lift when transitioning to level flight. During this transition process, it was necessary to ensure artificial stability and the use of novel control organs, which were to be developed with the help of the TMR. The device should also show whether the height can be regulated with the help of the lifting mechanism alone. The design of the supersonic aircraft and the proposal for the TMR go back to Alan Arnold Griffith . He later also designed a 44-seat supersonic jet with 56 Rolls-Royce RB.162 lift engines and 12 engines for horizontal propulsion.
Two thrust measuring rigs were built, which were formally assigned the RAF serial numbers XJ314 and XK426. The first flight attempts of the TMR took place tied up on the Rolls-Royce Hucknall Airfield near Derby in a gantry crane- like construction. For this purpose, a steel structure was built on a concrete base, which was composed of two 18.30 m (60 ft) high supports and a 21.35 m (70 ft) long cross member. A suspension mechanism prevented the device from sinking too quickly, and four ropes on the sides ensured that the TMR could not move out of the device. The first flight reached a height of 6.10 m. The first free flights were carried out from August 3, 1954, with heights of about 45 m were flown regularly. It was critical that a maximum rolling speed of 8 km / h was permitted on the ground, otherwise the device could overturn due to the small wheels and the high center of gravity. Because the roll control was only marginally effective, take-offs in crosswinds were always carried out with the nose or tail in the wind in order to be able to use the very quickly reacting pitch control when taking off.
23 flights were carried out over a period of five months. Another eight flights took place in Farnborough.
construction
The TMR had two Rolls-Royce Nene jet engines that were installed horizontally "back-to-back". The gas outlets were curved downwards by 90 ° so that the thrust vector of both engines went through the center of gravity. Additional measures were required to prevent the device from rolling or pitching in the event of an engine failure . The outlet of the front engine was divided into two parts and was located to the left and right of the single outlet of the rear drive. A separate 431 liter (95 gallon) tank was available for each engine, sufficient for a flight time of about 10 minutes.
The pilot's seat and the auto-stabilization system with its batteries were arranged on a platform above the drive units. The pylon construction under which the pilot sat served initially as a suspension device for the tied flights and later in a reinforced design for free flights as protection in the event of a possible rollover on the ground. The four-legged chassis could absorb impacts up to a vertical speed of 11 m / s. The height control was only carried out via the power levers, while the rest of the control was carried out via compressed air outlets on pipe arms at the front, rear and on both sides. The rudder pedals operated cables with which the boom with the outlet nozzles could be swiveled and a rotation about the vertical axis could be achieved.
The compressed air for movements around the transverse and roll axis was taken from the two compressors of the engines at several points and each collected via a pipe, which had a gradually increasing diameter over the circumference, and delivered to a pressure vessel located under the pilot's seat. The compressors used 9% of their power to deliver an air mass flow of 7.3 kg / s at a pressure of around 12 bar. The pressure vessel had two valves, one for pitch control and one for roll control, both of which were controlled by the auto-stabilization device. In the neutral position and in horizontal flight, the pitch control generated a thrust of 1.3 kN each. In the event of flight disruptions, e.g. B. a lowering of the nose due to turbulence, two electric motors were automatically started, which actuated the valves accordingly and released more compressed air for the front nozzle. The valves reacted very quickly with a reaction time of just 0.3 seconds from neutral to full deflection. The pilot had no mechanical connection to the controls, he only operated a rheostat with the joystick, which changed the voltage applied to the totalizing amplifier of the stabilization system. The lateral control worked in the same way, only the nozzle thrust was significantly lower at 40 lb each.
The thrust / weight ratio at the start was only 1.08, ie the thrust generated for the lift only marginally exceeded the vehicle weight. Due to the fuel consumption during the flight, the TMR became 60 kg lighter every minute, which significantly improved this ratio and thus also the flight behavior.
Aftermath
The results of the flight tests with the TMR led to the development of the first engine that was especially suitable for vertical installation in jet-powered, horizontally taking off VTOL aircraft. The Rolls-Royce RB.108 was then used for the first time in the Short SC.1 test aircraft. In the Soviet Union, the Turboljot (also known as the Turbolot ), designed by Aram Rafaeljanz and Vsewolod Matwejew and based on the TMR model, was built in 1957 . This suspension frame was powered by an AM-3 engine . The vehicle is exhibited in the Central Museum of the Air Force of the Russian Federation .
Whereabouts
The second copy of the TMR (XK426) was destroyed in an accident in 1957. The XJ314 is now in the Science Museum .
Technical specifications
| Parameter | Data |
|---|---|
| length | 8.54 m |
| height | 3.87 m (without attached pylon) |
| Wingspan (width) | 4.27 m |
| Max. Take-off mass | 3405 kg |
| Engines | 2 × Rolls-Royce Nene with 18 kN thrust each (4050 lbf each) + 2.9 kN thrust of the four control nozzles |
literature
- RA Harvey: Flying the Bedstead - Part 1 . In: Airplane Monthly, March 1985, pp. 116-119
- RA Harvey: Flying the Bedstead - Part 2 . In: Airplane Monthly, April 1985, pp. 178-180
- Roy Allen: Stranger than Fiction - The story of VTOL jet-lift . In: Airplane Monthly, August 2004, p. 32 f.
- JK B Illingworth: Flight Tests of a Hovering Jet-Lift Aircraft (Rolls-Royce Flying Bedstead) . Ed .: Ministry of Aviation, Aeronautical Research Council (= Reports and Memoranda . R. & M. No 3336). Her Majesty's Stationery Office, London May 1963 ( Online [PDF; 1.8 MB ; accessed on July 11, 2013]).
Web links
- Youtube video of a test flight (accessed on May 21, 2013)
Individual evidence
- ↑ Flying bed frame on avenita.net
- ↑ JK B Illingworth: Flight Tests of a Hovering Jet-Lift Aircraft (Rolls-Royce Flying Bedstead) . Ed .: Ministry of Aviation, Aeronautical Research Council (= Reports and Memoranda . R. & M. No 3336). Her Majesty's Stationery Office, London May 1963 ( Online [PDF; 1.8 MB ; accessed on July 11, 2013]).
- ^ Roy Allen, p. 35
- ^ Roy Allen, p. 34
- ↑ Turboljet in the holdings of the Monino Museum
- ↑ TMR in the Science Museum London ( Memento from October 4, 2013 in the Internet Archive )