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 on the 'Peregrine' engine covering power output, preignition, detonation, and spark plug performance.
| Identifier | ExFiles\Box 1\8\ B001_X100 Engine Chassis-page189 | |
| Date | 20th June 1932 | |
| X4027a To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/MJ.20.6.32. 'PEREGRINE'. POWER OUTPUT. We have now had some further running on this unit. We have obtained a maximum B.H.P. of 75 at 4500 which corresponds to 117 B.H.P. on the existing 'China', and therefore can be considered very good especially with a temporary induction system. We have had 70 B.H.P. at 5000 R.P.M., the unit running sweetly and no signs of valve bounce. We think we can get still better results using two inlet cam forms, the point we wish to improve being the low speed M.E.P. The best we have done at the present is about 8 lbs/sq.in. below J.1 with a similar induction system. We think the low speed M.E.P. is important because it is here that we shall get no assistance from the supercharger. We believe the larger inlet valve area/life of the Peregrine probably accounts for the loss of about 4 lbs/sq.in. low speed M.E.P. owing to reduced turbulence, and deal with this in a separate memo. However, we shall probably pick up appreciably by using two inlet cams which is the next test, since the exhaust duration seems to be one of the troubles. PREIGNITION. Cutting waterways under the plugs has completely overcome the preignition trouble. DETONATION. There is no sign of detonation on this engine at any speed. We agree that at present this may be due to the low speed M.E.P., but think that this engine should stand at least a 6:1 C.R. LONG REACH PLUGS. It will be noted that by increasing the plug reach a further .275, we have picked up about 3% in power at the top speeds. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||