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).
The Kestrel III MS 39 E.C. engine type test from January 1933, detailing improvements following a previous piston failure.
| Identifier | ExFiles\Box 179b\3\ img088 | |
| Date | 31th January 1933 | |
| c. to From Hs{Lord Ernest Hives - Chair}/LEH. c. to SS.{S. Smith} c. to Sor. c. to Rg.{Mr Rowledge} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Lr.{Mr Ellor} c. to Lp.{Mr Lappin} c. to Mr. Jaques. ORIGINAL x3196 Hs{Lord Ernest Hives - Chair}/LEH. S/MA.31.1.33. KESTREL III MS 39 E.C. TYPE TEST JAN:1933. RATING :- 330 HP. at 2,000 ft. ENDURANCE POWER :- 465 HP. NORMAL R.P.M. :- 2250. Repeat test as a result of piston failure on previous run during August 1932. Apart from the condition of the big end bearings, which was bad, and the breakage of one of the salt cooled valves after 94 1/2 hrs. running on the present test, the condition of the engine is an improvement over the previous test, run during August 1932, when piston failure occurred. The most noticeable improvements are :- Strengthened pistons Z.40529 in Std. H.D.Y. material These successfully completed the run, and no cracks appear to have developed at the top inside edge of the gudgeon pin bores, from which the previous failures developed. The increased gas ring clearance have given freedom from gumming, especially on the first two pistons. The modified scraper rings KT:10053, with .040" wide grooves, have been successful in increasing the oil consumption; the average being 5.28 pts/hr. for the endurance running as compared with 3.84 pts/hr. for the run of August 1932 and 3.73 pts/hr. for that of March 1932. The Lead Bronze main bearings, used with a nitro alloy crankshaft, were in good condition, the metal being intact. This repeats the successful results obtained on the run of March 1932, when after 100 hrs. running the Kelmit main bearings were in excellent condition, after running with a standard 3/NCR crankshaft. | ||