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).
Type test report on an F.27 engine with a 6/1 compression ratio, detailing new camshaft performance, detonation, and fuel economy.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan149 | |
| Date | 16th January 1932 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Lov.{Mr Lovesey} C. to Mr. Wor.{Arthur Wormald - General Works Manager} Cc. to ERg. Hy.{Tom Haldenby - Plant Engineer} Hs{Lord Ernest Hives - Chair}/Lov.{Mr Lovesey}5/RT.16.1.32. X3196. X4003. P.MS.No39. TYPE TEST WITH 6/1 COMPRESSION RATIO. We have completed preliminary tests on F.27. with the new camshafts for the 6/1 comp. ratio type test. These camshafts give a valve lift of .55 (.075 higher than std.) and approx. the same timing as standard. Results show that they are very suitable for the 6/1 compression ratio. Approx. the same horsepower is given with the high lift cams. as with the std. camshaft on similar engines. The power on the 6/1 comp. engine with the new camshaft is higher than the standard moderate by reason of the higher comp. ratio only. The high lift cams. have the virtue of reducing the detonation by approx. the same amount as it was increased by raising the comp. ratio from 5.5/1 to 6/1. The result is the 6/1 c.r. Type Test engine gives approx. the same audible detonation as the std. 5.5/1 engine. We benefit considerably in fuel economy. The full throttle consumption at normal R.P.M. is reduced from .53 pts/Hp/Hr. for the std. engine down to .50 pts/Hp/Hr. for the 6/1 engine. Throttled consumption also appears very good. We are now going to check this camshaft on the full supercharged engine and anticipate the power will be the same but detonation reduced. We shall probably be able to employ an appreciably higher take off boost for the same degree of audible detonation. At the moment the full supercharger gives considerably less 'trace of' power than the moderate. We are quite satisfied with the results of the new camshaft and recommend that the other sets of camshafts which are being prepared in the rough should be put through immediate-ly to the R.39 camshaft specification (R.{Sir Henry Royce} 36950) to be in read-iness for the comparative consumption tests on the Singapore II. The liner clearance in the block - at the base - is being increased on R.30. which we have found advantageous in reducing liner distortion. This engine should be ready for its 2 hrs. test on Tuesday or Wednesday. Hs{Lord Ernest Hives - Chair}/LOV.{Mr Lovesey} | ||