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).
Visit from Engineer-Commander Grylls to discuss Admiralty requirements for marine units and gearboxes for Motor Torpedo Boats.
| Identifier | ExFiles\Box 133\3\ scan0078 | |
| Date | 27th June 1939 | |
| To - Hs.{Lord Ernest Hives - Chair} from Wd.{Mr Wood/Mr Whitehead} c. to Sg.{Arthur F. Sidgreaves - MD} c. to Dh.{D. Henderson - Showroom} c. to Ht. c. to Rm.{William Robotham - Chief Engineer} c. to Wd{Mr Wood/Mr Whitehead}/Lm. Handwritten: By Wd.{Mr Wood/Mr Whitehead}24/RS.{Sir Henry Royce's Secretary}27.6.39. Handwritten: Good news Handwritten: Rm{William Robotham - Chief Engineer} VISIT OF ENGINEER-COMMANDER S.J.B. GRYLLS. Engineer-Commander Grylls came here on the 22nd inst. to discuss the Admiralty requirements with regard to Marine units for M.T.B's. They are very anxious to utilise Merlin Marine engines for their future M.T.B. programme but do not want to use The British Power Boat Co's gearbox because it does not meet their requirements. They have given a development contract to Mr. Wilson of The Self Changing Gear Co. to develop a gearbox with a 1.5 reduction in ahead (which will be a standard requirement for future M.T.B.'s) and a 1.75 reduction in astern, the maximum astern power to be 175 HP. Provision is also required on future gearboxes for coupling in an auxiliary engine to look after manoeuvring, creeping up to attack, and to drive generators while the boat is laid up in harbour. GEARBOXES. For future Marine units they require all the accessories to be driven from the engine. The reduction gear in ahead requirement is based on the comparative performances of the P.V. 70 ft. boat and the latest Vosper boat. By plotting r.p.m. against boat speed the Vosper boat gives speed proportional to r.p.m. up to the maximum engine and propeller speed of 2000 r.p.m. whereas the P.V. curve flattens off at speeds above 2400 r.p.m. and the increase of speed above 2400 r.p.m. is very little for a large expenditure of power. The Admiralty intend to send us a specification for future gearboxes for our guidance should we decide to go ahead with a R.R. gearbox. In the meantime, they are seeking our co-operation in developing the Wilson gearbox by asking us to run it under a suitable contract. The proposal with regard to testing is that we should do the equivalent to a 100 hours type-test on the gearbox before it is approved as being suitable. | ||