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 Engine Unit M.III No.7 following 21,000 miles of running, detailing performance and suitability for production.
| Identifier | ExFiles\Box 108\3\ scan0226 | |
| Date | 9th May 1938 | |
| ALL TESTERS To Sg.{Arthur F. Sidgreaves - MD} FROM RM{William Robotham - Chief Engineer}/IEH. O.{Mr Oldham} HS.{Lord Ernest Hives - Chair} O.{Mr Oldham} HY.{Tom Haldenby - Plant Engineer} O.{Mr Oldham} RHC.{R. H. Coverley - Production Engineer} O.{Mr Oldham} HS.{Lord Ernest Hives - Chair} O.{Mr Oldham} RH.{R. Hollingworth} O.{Mr Oldham} MX.{John H Maddocks - Chief Proving Officer} C. Cull. O.{Mr Oldham} ERS. S. WH. RM{William Robotham - Chief Engineer}/IER.3/EH.9.5.38. 600A I. I-S. TESTS IN FRANCE. 20.C.VI. - 27/30. Report on 21,000 miles running including 15,200 miles run from Chateauroux, 2117 miles by Ex. as reported in Ex.1/H.4.4.38, and the remainder in England. Specifications EFD/NBB/31.1.38. Modifications during mileage RM{William Robotham - Chief Engineer}/IEH.8/EH.6.4.38. ENGINE UNIT M.III NO.7. Subject to the modifications referred to, the engine appears suitable for production. It was smooth and silent up to 3000 r.p.m; vibration was noticeable at this speed and above. With the axle ratio that it is proposed to standardise, this is equivalent to 74 m.p.h. in top gear. High engine speeds in top gear were more easily obtained and held than with the present standard 27/30. Larger rear tyres were therefore fitted for part of the mileage to represent the higher axle ratio which has been instructed for production. On top gear 4300 r.p.m. could still be maintained and 4450 r.p.m. reached under favourable conditions. The standard of smoothness throughout the range deteriorated slightly towards the end of the mileage and a rumble was audible when idling which could be eliminated by | ||