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).
Letter from F.M. Aspin & Co. discussing port design and proposing a flow measurement test against poppet valves.
| Identifier | ExFiles\Box 134\1\ scan0219 | |
| Date | 29th June 1940 | |
| 1129 TELEPHONE - BURY 1554 TELEGRAMS - "NIPSA" BURY CABLES - " " WESTERN UNION "NIPSA" BURY F.M. ASPIN & CO. LTD. INTERNAL COMBUSTION ENGINES ELTON BURY ENGLAND Chairman and Managing Director. F.M. ASPIN Directors - T.B. ASPIN W.R. CROWN L. CLOUGH C. RIDDEL G.E. VARLEY YOUR REF OUR REF FMA/AG 29th June, 1940. W. A.{Mr Adams} Robotham, Esq., Messrs. Rolls-Royce, Ltd., DERBY. Dear Mr. Robotham, I am in receipt of your letter of the 28th inst. and note your remarks. Perhaps you would be good enough to send us a diagram showing the target which we have to shoot at. This would be of great assistance, but at the moment we have altered the rotor to a new port arrangement which gives us greater orifice coefficient, and are running the same under 300 lbs. compression pressure to ascertain if mechanical working is being upset. In the past we, at one time, considered the port opening extremely important on small single cylinder engines, but actually found that when we reduced this opening to our standard practice we got better performance instead of worse. How this applies to the larger cylinders we cannot say, as we have only just commenced serious work on this type of cylinder. There is one thing, however, which we consider should not be overlooked, that our ports have considerably less obstruction than poppet valve ports and that at high gas velocities this must have some effect, as changes in form and area considerably upset flow. To clear the above mentioned points, I am arranging to have some flow measuring equipment rigged up, so that we can compare the flow through a poppet valve port with valve propped wide open, against that through an Aspin port, then take flow readings at various degrees of opening. This should be very interesting. ALL COMMUNICATIONS TO BE ADDRESSED TO THE COMPANY | ||