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).
Test report detailing engine backfire tests, consumption loops, and performance analysis.
| Identifier | ExFiles\Box 179\2\ img190 | |
| Date | 27th January 1932 | |
| -3- then run up to nominal power at nominal R.P.M. Heavy backfires were produced by earthing the inlet mag. Backfires carried out on this brake setting were as follows :- 20 at 2500 R.P.M. 20 2250 " 20 2000 " 20 1750 " Further backfire tests as above were carried out using standard intakes. We state here that no flames appeared in the air boxes or outside the standard intakes as the French Schedule says "No flames should develop outside in the course of the above tests". Test C.3 was carried out at 2500 R.P.M. and 414 BHP. (9/10 of nominal power i.e. 460.) The running time was extended to two hours in order to obtain a reliable oil consumption figure. This averaged 3.7 pints/hour. The following consumption loops were now carried out at nominal R.P.M. using D.T.D.134 fuel in order to enable us to state a definite fuel consumption under the various conditions if necessary. (1) Full throttle 11,500 ft. pressure in air intakes.)Curve (2) 460 BHP. Ground Level pressure in air intakes. )280 F.{Mr Friese} (3) 414 BHP. 11,500 ft. pressure in air intakes. )Curve (4) 414 BHP. Ground Level pressure in air intakes.)281 F.{Mr Friese} SUMMARY. The engine has not yet been stripped and so we cannot say definitely that no damage has occurred as a result of the backfires. There is, however, nothing in the general running of the engine which suggests internal damage. With regard to the backfired tests. It has been pointed out earlier in this report that as soon as a backfire occurs the engine stops. We suggest that the French schedule of tests has been drawn up to cover engines fitted with multi carburetters which operate under the supercharge pressure e.g. Hispano. An engine of this type could run for a considerable period backfiring due to derangement of one carburetter and it is conceivable that under these conditions trouble might arise. The only point of note on the rating tests is that the French correction for altitude conditions gives a power which is approx. 3% down on the English correction - AP.840. Hs{Lord Ernest Hives - Chair}/H.G.V. | ||