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 and benefits of ethylene glycol cooling in Kestrel aero engines.
| Identifier | ExFiles\Box 173\1\ img430 | |
| Date | 20th February 1934 | |
| To Rm.{William Robotham - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Lov.{Mr Lovesey} Hs{Lord Ernest Hives - Chair}/Lov.{Mr Lovesey}5/MJ.20.2.34. Dear Rm.{William Robotham - Chief Engineer}, Many thanks for your note and the various aero information you have sent along. At the moment we have a very lively interest in Ethylene Glycol cooling and already have the Tollerton Hart flying with it and have done tests on the P.V. Fury. Now that we have passed a Type Test on the Kes.Vl.{V. Lewis / Mr Valentine} engine - i.e. Kestrel with Gos. blower rated at 600 HP. at 11,000 ft. - we wish to be in the position to fit it in existing machines without alteration and by means of Glycol we can use the existing size of radiators and cooling systems provided for the old 480 HP. engines. Taking the Hart as an example with its existing 1.8 sq.ft. radiator and the 600 HP. engine it results in the peak temp. on the climb reaching 110°C. and in level flight cruising 104°C. both under Tropical Air temperature conditions - or a condition which we have never been able to fulfil without boiling even with the lower powered engine. Under English summer conditions the climb will reach 98°C. and level flight 91°C. You will see that for the purpose of getting in with the 600 HP. engine we are not aiming at high temp. cooling - the high temperatures are only of short duration encountered on the climb. Actually the benefit of Glycol is more than indicated by the figures because at 15,000 ft. where we reach the 110°C. under Tropical conditions the boiling point of water is only 85°C. which shews what we have in hand over a water cooled system. Our next move is to go to moderate high temp. cooling so that we can get a reduction in radiator size. What we are anxious to know is the peak temperatures allowed - which would be encountered on the climb - on the American Prestone cooled engines also what are the level flight cruising temperatures. In our own case we think it will be quite permissible to permit a peak temp. (which will only be of short duration) up to 130°C. or even 150°C. Actually we see no reason why we should not operate at air cooled cyl. barrel temps. On the 'Fury' we can use 1.5 sq.ft. radiator for 600 HP. without exceeding 108°C. on climb in English Summer conditions. | ||