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).
Aircraft engine development, discussing cooling systems, brazing techniques, and competitor engines.
| Identifier | ExFiles\Box 179b\3\ img035 | |
| Date | 14th January 1931 guessed | |
| Cont'd.{John DeLooze - Company Secretary} Operating at 180ºC. they use a radiator on the single seaters of .835 sq.ft. or 120 sq.ins. with 4mm. tubes. A slightly smaller diameter inlet through streamline cooling is employed. This has catered satisfactorily for 650 H.P. but I could not get figures on the aircraft speed. They say the liquid flow on this engine is bad. Future Development. They are developing an engine with steel cylinders and jackets brazed together forming a completely sealed block except for the water inlet and outlet - no joint at all. The head is a one piece alum casting sealed in a similar manner and with its own inlet and outlet. The joint between the two is therefore dry and they have separate water circulations. The brazing is done by a special electrical process by placing brass wires between the joints and brazing electrically. This job is not done by Curtiss. Curtiss Wright are not very enthusiastic about liquid cooled engines - most of their energies expended in air cooled. Water and Prestone cooled engines only due to demand of Naval Dept. for use in flying boats where long periods of taxying cause overheating of air cooled engines. Heron says U.S.A. haven't got a real up to date water cooled job and the big demand is for air cooled radials. He thinks Glycol only useful for cylinder development. Air Cooled Engines. The new Wright H-151 installed in the Northrop monoplane used by Frank Hawks has 14 cylinders in two rows 5 x 5.5 and 1510 cu.ins. 6.25/1 compression ratio. It gives 725 B.H.P. at 2,350 R.P.M. 8.5" Hg. boost and 140 B.M.E.P. It has passed its type test of 100 hours 50 hours full throttle 50 hours 95% F.T. and 5% in excess of 2300 r.p.m. They are developing another engine very similar but slightly larger bore having 1570 cu.ins. capacity. It is still on the secret list but I managed to get a look at it. This has 1/1 blower gears with 11" dia. rotor and about 4" wide at tips. It gives 780 H.P. at 10,000 ft. tested with intake pressure and temperature equivalent to 10,000 ft. The results however are not corrected for back pressure. They are also testing some intermediate gear ratios on blower. The weight of the engine is somewhere about 800 lbs. | ||