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).
Technical memorandum detailing the non-debatable advantages of the Aspin valve engine over single sleeve engines.
Identifier | ExFiles\Box 144\4\ scan0085 | |
Date | 1st May 1940 | |
- 2 - Cont'd.{John DeLooze - Company Secretary} He has stated that he has had over 1,000 hours running on this particular valve and head. Aspin admits that he has had all sorts of trouble with the valve but asserts that it is now reliable under single cylinder conditions. Though the M.E.P. of this engine is high, the rotational speed of the engine is exceedingly low; the maximum revs of the engines being somewhere about 1750. On the other hand, Aspin has had engines running at well over 5,000 r.p.m. but we do not think that he has accomplished any protracted endurance on them. The investigation that we have so far made indicates that the Aspin engine has the following non-debatable advantages over the single sleeve. NON-DEBATEABLE ADVANTAGES OF THE ASPIN VALVE. 1. Shorter Engine. It seems to be necessary to spread the cylinder centres on the sleeve valve about 5% more than those on a poppet valve engine. The Aspin engine can be the same length as a poppet valve engine. 2. Cooler Piston. In the Aspin engine there is no sleeve between the piston and the cylinder wall. 3. Absence of Balance. There is no necessity to balance the Aspin valve gear. 4. Easier Manufacture. The Aspin conical head should be easier to manufacture than a sleeve. 5. Less disasterous in case of failure. If the valve gear on either a poppet or single sleeve | ||