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).
Performance characteristics and gear configurations of Wright engines.
| Identifier | ExFiles\Box 178\2\ img067 | |
| Date | 9th March 1940 | |
| Serial No 11 OY 2/D/Mar 9-40 March 9 1940 Rolls-Royce Ltd. Derby England Rn{Mr Robinson} In my notes to you on the Wright engines, I left out the thing which probably interests you most-the February schedule of performance characteristics. Apparently my guesses on the reduction gear with 24 pinions were not far wrong. Reduction Ratio which I guessed at was .558 and ratio given in their schedule for the double row 14 cylinder is .5625. This calls for pinions which are only one ninth of the annulus diameter. The 18 cylinder engine is not mentioned officially as yet. And the new power ratings of 1700 and 2200 H.P. are not given. The 24 pinion epicyclic gear is mentioned as applicable to the single row C-200 engine. The 6 pinion gear of .667 ratio (pinion=1/4 of annulus diam) is also mentioned as applicable to 14 and 9 cylinder engines. Since the absolute limits in ratio of a plain epicyclic are between .500 and 1.0, I cannot explain the gears mentioned on first sheet giving .500 and .4375 ratio. I think these must be Gleason bevel-gear epicyclics. I do not think Wright made any epicyclics with compound planets. We did not see any of the two speed superchargers shown in the schedule. I have already written you that Pratt & Whitney use turbo-drives for transition between speeds. But we understand Wright use only spring loaded friction clutches. I cannot say whether they have discovered the use of hard felt impregnated with Bakelite, used by G.M. on similar clutches which run in oil. I hope the enclosed data will interest you. OY Copy to: J.M.Lessels | ||