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 W. H. Colt Ltd. discussing bonnet ventilators and a new fan design with automatic blade-pitch adjustment.
| Identifier | ExFiles\Box 119\3\ scan0186 | |
| Date | 25th November 1931 | |
| W. H.{Arthur M. Hanbury - Head Complaints} COLT, LTD. BETHERSDEN NEAR ASHFORD - KENT - TELEPHONE BETHERSDEN 6 TELEGRAMS COLT BETHERSDEN KENT BUSH HOUSE ALDWYCH LONDON. W.C. 2 LONDON DIRECTOR: I. J.{Mr Johnson W.M.} O'HEA, F.C.I.S. TELEPHONE AND TELEGRAMS TEMPLE BAR 5112 WHC/V/P Your Ref.Hs{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey}2/AD Messrs Rolls-Royce Ltd. Derby. Nov.25th, 1931. Attention A.J.Lidsey,Esq. Dear Sirs, We are obliged for your letter of 23rd inst. and note that our letter to Mr Lappin has been passed to you. Re Bonnet Ventilator: we are glad to learn that the pair in aluminium have reached you and that they will be tested out shortly. We have one other pair in brass which is slightly more rigid and in case you have use for it we shall be glad to let you have it. Re Fans: we realise that your selection of design is the outcome of careful tests carried out with fans of conventional details. Our fan represents an entirely new principle and for this reason does not lend itself for comparison. Briefly the points are these: our fan aims at furnishing more air for an equal HP consumption, air volume capacity becoming more constant whilst churning is eliminated. There is no overloading of fan belt and therefor no slipping at high revs.. HP required does not rise above a certain point, its average being about 20% lower than with normal fans. In as much as our fan is still in the final testing stage we are unable to assist you at the moment with definite figures. All car fans being subject to chassis conditions such as radiator,casing, undertray,bonnet,etc. it is unavoidable to carry out tests individually, for which reason we should have appreciated two of your fans which we could include in our present tests. The principle of our new fan lies in the automatic setting of blade-pitch according to revs. This is the only solution to the fan problem with continuous variations of fan-revs, such as occur on the car fan. A car fan performs efficiently only under constant rates of revs. We attach two charts from the curves of which you can see the difference in performance between a normal and our new one. Handwritten text: r1085. | ||