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Aviation History
1946
1946 - 0764.PDF
394 FLIGHT APRJL I 8TH, 1946 ROLLS-ROYCE NENE I 5OOO r- 4SOO- 4.6OO 4.4OO X 42OO 4.000 3,8 • 3,600 • a •5 o z O o BOO • 7OO the starter button brings the clockwork time switch into operation. In timed sequence,- current is supplied to the ignition coils, flame igniters and the starter motor. The motor takes up the drive and cranks the engine at low speed for about 5 seconds, after which a relay closes to allow full excitation of the motor. The time switch completes its cycle in 30 seconds and cuts off all current. If, however, the engine starts and reaches a predetermined speed prior- to this, starter, ignition coils and flame igniters are auto- matically cut out. Nene units at present in production are rated at 5,000 lb thrust. This is neither the maximum at present available nor the ultimate possibility. A thrust of 5,500 lb has already been obtained on the test bed. The average figure during development was 5,150 lb, which represents the following component efficiencies: Compressor, 76 per cent; combustion, 98 per cent; expansion; 93 per cent. Design throughout has been with the aim of facilitating progressive development in the familiar Rolls-Royce tradition. The first aircraft to be powered by the Nene was a Lockheed X-P80 Shooting Star, and recently tests have been conducted on a de Havilland Vampire. In both instances an improvement in performance was ob- tained. With the American aircraft speeds of the order of 580 m.p.h. and an excellent rate of climb to 42,000ft were achieved. However, new aircraft will be required to take full advantage of the thrust now available from the Nene. Several prototype aircraft, both single and twin-unit designs, are under construction, but at present no information can be released concerning them. - The high thrust and light weight of the Nene jet engine make it a potential competitor of the orthodox reciprocat- ing engine for medium range heavy tjombers. Recently Dr. S. G. Hooker gave estimated performance figures for a Lancaster powered with four Nene umts. It was claimed V £ 600 \ *. \ • \ \ ^^^ I.C.A.N. CONDITIONS TEMPERATE SUMMER _._ TROPICALSUMMER MM — \ •^ y y •~m~l --* > ^^ L /^ y / y y y / / 2.2OO 2.1OO 2,000 1900 j 1.8OO 1 1.7OO 36O 34O o 2 o32O 1OO 2OO 300 4OO 5OO AIRCRAFT SPEED M.P.K. 1OO 2OO 3OO 4OO SOO AIRCRAFT SPEED M.RH. 6OO 3OOg 28O 26O 24O FUEL CONSUMPTION AT (2.3OO RP.M FUEL CONSUMPTION AT II.SOO R.P.M. FUEL CONSUMPTION AT 11.5OO RP.M Estimated performance under various atmospheric conditions. (Left) at sealevel. (Right) at 30,000 feet. that with an all-up weight of 60,000 lb the cruising speedwould be about 400 m.p.h at all altitudes up to 35,000ft. With existing fuel tanks, range would be approximately1,000 miles at 30,000ft. As the installed weigrit of the four Nene engines would be only 8,000 lb as compared to12,000 lb for four Merlins, tankage could be increased and the range extended. To obtain a 25 per cent increase inpower accompanied by a 33 per cent reduction in installed weight is an indication of the importance of a change fromreciprocating to rotating power units and a hint of the performance expected from specially designed aircraft. 5.000 4.000 ^ zoo too 1O.OOO 2OOOO XlPOO 4O.OOQ O ALTITUDE FT 1O.OOO 20.000 30XXO 4O.OOO O- ALTITUDE FT \ s, M \ N T N ^> /FUEL s VRUST s> / 1 CX)N 12.3O ^6OOM AT 1 HRU? JUMPTi 3 R.P FUEL AT 1 J.3OO • AT 1 K ON M. R.P.M 15O0 ^\ CONSUMPT t.50O R.P.* ^s N .P.H. ?.P.M. ON A. 3.OOOJ; aI* 2000 LOOO 2aooo JOJOOO 40000 ALTITUDE FT. Estimated performance at aircraft speeds of 400, 500 and 600 m.p.h. at altitudes ranging from sea-level to 40,000 ft.
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