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).
Merits and procurement options for different types of engine blowers.
| Identifier | ExFiles\Box 179b\1\ img118 | |
| Date | 17th October 1932 | |
| ES.) FROM R.{Sir Henry Royce} BY ) C. to SGR. WGR. HS.{Lord Ernest Hives - Chair} BA. ORIGINAL BENSPORT BLOWER. Firstly, the question of the Bensport blower seems to be very serious. Firstly, the Powerplus now seems a waste of time. At one time I thought it a fair second chance to the Roots, but never expected it would be as reliable at the latter, and even with its special lubricating arrangement does not seem passably reliable, and we think it hardly gives us the characteristics we want for this particular chassis. Personally I should expect much better results from a characteristic as produced on the Alfa Romeo, in which we get the maximum boost at maximum speed, that is, we do not wish for the high boost at moderate speeds with a falling off at high speeds, because this is so bad for detonations. All things are shewing us that we must put our whole energy and chief faith in getting a suitable Roots blower, and not waste any more time and money on the Powerplus, leaving it to the Powerplus people to do as they wish if they are anxious to make any further attempt at supplying us with a blower. Personally I have had little faith in their device because I understand it involves a change of angular velocity of certain parts at the rate of 10,000 per min., and other troublesome forces, while the Roots suffers none of these disadvantages, and relatively speaking appears to be the best of all for reliability. Naturally I cannot do much towards getting you an actual blower, but as far as I can see, two sources of help are open to us, the first being to buy from America, from the Allison Co. a blower of the required size. Referring to their model C.2. this appears to have the better proportions, but has about 6 or 7 times the capacity we require, and to get the job moving it might be as well to stick to the proportions of this blower, and reduce the scale until it gives us the 1800 to 2000 cc. per rev. that we seem to think about right. We think it would not take long to make a picture of the blower to these proportions. Our next move would be to go to Messrs David Brown of Huddersfield, and find out whether they are prepared to make us a complete blower, or to machine the rotors. If they could machine the rotors we think there would be little trouble in doing the rest ourselves. I may add that we shall not be happy at W.W. until we see a drawing of the Roots type blower, with the Bensport engine, which is the one we require, and also to hear that you are making some very definite progress towards getting one. R.{Sir Henry Royce} | ||