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).
Investigation into cylinder joint failures and high temperatures on evaporatively cooled Kestrel engines.
| Identifier | ExFiles\Box 178\4\ img061 | |
| Date | 7th March 1932 | |
| From RB{R. Bowen}/LAV. C. to Mr. H.{Arthur M. Hanbury - Head Complaints} C. to Mr. S. L. C. to Mr. S. F.{Mr Friese} KESTREL ENGINE - CAUSE OF FAILURE OF CYLINDER JOINT RING. ------------------------------------------------------- ALLOY CYLINDER BLOCKS - EVAPORATIVE COOLING We can say that the most unreliable feature of the 'Kestrel' engine in service is the top cylinder joint, and that trouble has become considerably more pronounced and serious in M.1 evaporatively cooled engines. Consequently we have investigated this subject from the following points of view:- The Ideal Temperature :- The possibility of the Alum. joint ring reaching high temperatures when running evaporatively cooled was suspected and investigation was made by means of Thermo Couples inserted in the actual joint ring, at the position shown on appended prints. It may be appreciated that the temperatures recorded are really outside surface temperatures of the ring - not of the surface which is in contact with the coolant. Therefore, on no account can these figures have been accepted if it be assumed that the ring must have been partially insulated from the coolant by local over-heating, or an insulating film of low temperature steam. In an earlier report on this subject - where we used normal engines in the test - we showed that the 50% water cooled engine could be run fully supercharged up to full throttle, giving 317 B.H.P. without the top joint ring reaching more than 120 C. Attempts to do the same test, running evaporatively cooled proved to result as high as 700 C. and resulted in water line developing a leak, burning the film. This engine would not stand running at the "take off" boost of 1.5 lbs/sq.in. without excessive temp. rise. The engine with improved circulation - i.e. larger water inlet and larger outlet water pipes (as Type Temp. B.M.S.) was tried to repeat all normal conditions to "take off" boost under evaporatively cooled conditions without undue temperature rise, and a test was made to see the limiting boost which could be used where trouble occurred. By progressively increasing the boost above the std. "take off" value of 1.5 lbs/s.in. and testing the normal transport service running (approx. "take off" + 4d) we found the temperature of the joint ring increased and soared up | ||