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).
Letter from Specialloid Ltd. discussing piston clearances, measurements, and testing.
| Identifier | ExFiles\Box 148\4\ scan0310 | |
| Date | 26th October 1934 | |
| 291034. ALL COMMUNICATIONS TO BE ADDRESSED TO THE COMPANY ON AIR MINISTRY LIST Specialloid LIMITED Metallurgists-Engineers-Founders Friern Park·North Finchley·N·12 SOLE MANUFACTURERS OF Specialloid PISTONS CHAIRMAN J.{Mr Johnson W.M.} H.{Arthur M. Hanbury - Head Complaints} PLATFORD MANAGING DIRECTOR: H.{Arthur M. Hanbury - Head Complaints} N. BATES, A.M.I.M.E. TELEPHONES: HILLSIDE 2233 5 LINES TELEGRAMS: "SPECIALLOID-LONDON" CODES: MARCONI A.{Mr Adams} B. C. 6TH EDITION BENTLEY'S OUR REF LPG/EJ/SERVICE. YOUR REF Hs{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer}14/KW. DATE 26th October, 1934. Messrs. Rolls-Royce Ltd., Derby. FOR THE ATTENTION OF MR. W.A. ROBOTHAM. Dear Sirs, SUBJECT: SPECIALLOID PISTONS. In reply to your letter of the 23rd October we agree that our clearance at the top of the skirt on the thrust face of .0051" could probably be reduced without resulting in seizure. The clearance of .0051" only affects the top of the skirt for the taper gradually reduces it to .0035". We propose that the actual land diameters are subject to test, that only one set of pistons are finish machined, the remaining two sets to be held semi-finished pending test results. Following initial test the remaining two sets may be finish machined and then subjected to your production, bench and extended road test. We have based our test clearances on experience gained with various types of engines and would prefer to maintain, for the initial test, the allowances which we have proposed, for although we consider the skirt clearance may be decreased, we do not anticipate cold piston knock. Regarding your last paragraph we should be pleased to arrange for the test pistons to be | ||