From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Flight test report on engine performance with heated air intakes at various altitudes and temperatures.
| Identifier | ExFiles\Box 179\2\ img125 | |
| Date | 5th January 1932 | |
| -2- the A/C at full rich due to the concentrated wet mixture favouring only these cylinders. Returning to the heated air intakes at 20,000 ft, there was naturally a gain in R.P.M. using full A/C but the actual amount we could not determine because the rev. counter drive broke during the test. At no time during the climb was black smoke visible at the exhaust ports, and at very low air temperatures the engine ran just as smoothly as at low altitudes. Another very definite improvement was appreciated when gliding with the throttle shut. A glide through several thousand feet at these low temperatures could be made, and the engine would open up perfectly without any signs of "building up". With the standard intakes the throttles have to be opened up every few seconds to prevent choking up with wet petrol. The tick over on the ground was also improved. SUMMARY. From our flight tests on the J.F. we have definitely established the considerable improvement to be obtained by the use of heated air intakes. The advantages we have observed are :- (1) No tendency for the engine to "cut" at temps. as low as -38°C. (this is the lowest we have been able to get on the J.F.) The distribution and general running of the engine is as good as the standard at low altitudes. (2) Normal operation of the A/C is obtained at low air temps. (3) No "building up" experienced when gliding with throttle shut at high altitudes. The results in flight, we consider, justify further investigation of the scheme. We can continue tests on the bench to investigate the power loss previously observed, and this, we think, can be reduced by enlarging the breathing area through the tubes. It must be remembered the present scheme being experimental the tubes were built into a standard carburetter intake pipe with the consequent reduction in breathing area. We are also going to conduct tests on the J.F. to determine what this small power loss means in the performance of the machine. Timed climbs will be made with and without the heated air intake when weather permits. He/Lov.{Mr Lovesey} | ||