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).
Compression ignition aircraft engines and propeller developments, including blade materials.
| Identifier | ExFiles\Box 179\3\ img146 | |
| Date | 1st April 1932 | |
| -5- COMPRESSION IGNITION AIRCRAFT ENGINES. Pacards, who are the only firm in America producing diesel engines for airplanes on any major scale, were singularly reticent about their progress. It is significant, however, that they have returned to the automobile business with renewed vigour with their new light eight. From outside sources we learnt that, practically speaking, the Pacard diesel is dead. We certainly did not come across any on the commercial lines over which we flew. With regard to research, as we have previously pointed out, at Langley Field on single cylinder work there is considerably more enthusiasm for direct petrol injection with safety fuel than for compression ignition. The same atmosphere was prevalent at the Curtiss Wright and Pratt & Whitney plants. PROPELLERS. These have been receiving a great deal of attention and the testing equipment allotted to them at Wright Field is exceedingly elaborate. Fixed Pitch Propellers. In the two bladed propellers the tendency seems to be to utilise the shorter blade. At Wright Field they have satisfied themselves that they get greater efficiency with the three bladed propellers than with the two bladed propellers and are even considering four bladed propellers, though one would imagine these would suffer from interference. Blade Materials. With regard to the blade materials, aluminium alloy is the standard material. Magnesium blades have been tested and passed for flight in the smaller sizes and are at the present moment undergoing tests in the larger sizes. The magnesium blades come out about 2/3rds of the weight of the duralumin blades. However, the Army and Civil Authorities do not seem very enthusiastic about magnesium blades, the development which is appealing to them most being the hollow steel bladed propeller. This, for some time has been in abeyance but has recently been brought to the front by the Pittsburg Screw & Bolt Corporation which have been working on the job about 18 months and are certainly now producing a wonderfully fine job. They have just received an order for 100 blades from the Army though the experimental tests have only just been completed. | ||