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).
Temperature readings taken to investigate vapour-lock issues and the effectiveness of an isolating plate near the petrol filter.
| Identifier | ExFiles\Box 27a\1\ Scan297 | |
| Date | 13th August 1935 | |
| To: Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Nº 2. Sr21/Dm{D. Munro}13.8.35 We made an isolating plate composed of two sheets of aluminium, in between which was sandwiched a piece of asbestos, and rivetted together. This, we placed in front of the petrol filter. A thermometer was placed behind this radiator of sorts and another in front of it. For your information, I give you the following readings taken by our own mechanic who accompanied the customer for a couple of days.: | | | Rear of Isolating Scheme. | Front of Scheme | Temperature on Radiator Thermometer | | :--- | :--- | :--- | :--- | :--- | | 27th August. | Between Paris and Troyes. | 58º | 72º | 76º | | " | Between Troyes " Basle | 60º | 70º | 75º | | 29th August | St Julien Pass (2272 M) | 62º | 74º | 86º | | 30th August | Splingen Pass | 58º | 70º | 79º | | 31st August | Brenna Pass | 56º | 66º | 76º | In case it is of interest to you, the dimensions of the protecting plate which was put on in a manner to ensure free circulation of air round the petrol filter, were length 8½", width 7", distance from dash 3.3/4". I am going to try this device on my B-1-CW, and will keep you informed of what happens. Personally, I am of the opinion that all petrol filters and petrol pumps have had their day under the bonnets of cars. I do sincerely hope that you will do something to help us out of this difficulty. I have just had Faroux on the telephone. He confirms his telegram and points out that all cars down there are suffering from the effects of vapour-lock when using a more volatile type of petrol like Esso. He is so interested in this matter, that he has been getting right down to it, taking temperatures, dismantling petrol pipes into and out of the petrol pump, in order to find out where the vapor-lock is, etc He is now going to fit what is known as an anti-vapour lock device, and then carry out experiments so as to ascertain if this device is effective. He will then make us out a very thorough report on the result of his investigations, which will undoubtedly prove to be of great interest to all concerned. He has already discovered that during his climb of the Galibier Pass the temperature under the bonnet was 82º, and points out quite rightly that this being so, we are bound to get a vapour lock, as with the petrol used such as Esso, which contains quite a large quantity of alcohol, this latter carburant vaporises at 60º and we therefore run into this trouble. [Signature] | ||