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).
Specifications and calculations for a gliding winch.
| Identifier | ExFiles\Box 175\2\ img051 | |
| Date | 5th February 1941 | |
| SECRET. To Rm.{William Robotham - Chief Engineer} from Ev{Ivan Evernden - coachwork}/JD.{J. Draper - Frames} Ev{Ivan Evernden - coachwork}/JD.{J. Draper - Frames}4/SW.5.2.41. 2056 Gliding Winch. The required figure of 1,000 lbs. at 75 m.p.h., quoted in the draft specification, implies 200 h.p., and we feel on investigation that it would be advisable to run the Phantom lll engine at its peak r.p.m. of 4,000 at the wire speed of 75 m.p.h., to be reasonably safe. This implies that 93.5% overall efficiency is necessary to obtain 200 h.p. at the wire, using open exhaust power figures. Since the b.m.e.p. at 4,000 r.p.m. is 94 lb/ins² and the maximum b.m.e.p. is 118 lb/ins² at approximately 1,800 r.p.m., the maximum pull in the rope will then be 1,256 lbs plus a further increase due to the reduced effective drum dia., when the wire rope is uncoiled. The guillotine you talk about, we assume is to cut the cable in the case of an emergency. --------- Ev{Ivan Evernden - coachwork}/JD.{J. Draper - Frames} | ||