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).
American engine starter technology, valve design, and testing procedures.
| Identifier | ExFiles\Box 27\3\ Scan222 | |
| Date | 15th May 1939 guessed | |
| 16. Thes. figures were not quoted as being accurate, but were given as being a rough illustration of what had occurred. The Eclipse people were quite emphatic that this was not a question of Coffman versus Eclipse but of Cartridge versus Electric starters. The strategic questions of rapid starting in time of emergency with exited personnel over-doping the engines do not appear to have been given any consideration in the States. Eclipse are developing for the Army a starter combining direct cranking with inertia at will. This starter can be used as a direct electric starter like the E.160 or the inertia flywheel can be brought in to get the engine moving, after which the engine is cranked directly. A higher cranking speed is claimed and a lower battery current consumption. The clutch setting has not been increased, however, so that the starter, although weighing 5 lbs. more than the E.160 can only start the same size of engine. Valves Both Companies are using hollow headed sodium filled valves. The stems are not nitrided. The only trouble appears to be a certain amount of corrosion under the head of the valve. They are very interested in 80/20 for this application. Testing Both Companies are well provided with test stands. Pratt & Whitney have 12 hangars and 7 brakes, including 2 of 3000 HP and one of 4000 HP; 9 S.C. Units including one of 200 HP and a 400 HP Blower unit for experimental and development work. They have about 30 test stands in all and Mr Hobbs told me that his testers are working about 16 hours a day. Wrights have about 12 experimental main engine test stands. A great deal more testing is done before type testing than is usual in this Country. For instance, Mr. Hobbs said that on the '2800' engine, 3200 hours of development running was carried out including 1200 hours at take-off power before a type test was attempted. | ||