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).
Proposal for a stiffener bracket modification to the 'Wraith' chassis to prevent frame cracking.
| Identifier | ExFiles\Box 10\2\ 02-page28 | |
| Date | 24th January 1947 | |
| A.D.O. 119/AD/JEC. STIFFENING FOR ENGINE MOUNTING BRACKETS Without these plates, the top longerons have been found to crack and the side members to break off just behind the dash. A number of cases of the former and one of the latter have already been reported, and the fitment of these plates to all existing chassis and to all future production is considered essential. Attached is a new design of stiffener bracket which it is proposed to fit to all 'Wraith' chassis now in production and to all future 'Wraith' chassis. These replace the existing parts Nos. F.60010 and F.60011 which were introduced in May, 1939, to overcome the same trouble. The cause of this cracking is the continual flexing of the framework due to engine vibration. At our request, Messrs. Park Ward made an investigation on one of their cars and found that a movement of .012" occurred at the front engine feet when the engine was running at between 1,700 and 1,800 r.p.m. The new design of stiffener has been arranged to provide the maximum amount of stiffening to the frame with the minimum amount of alteration to the chassis and to existing jigs. The proposal has the full approval of Messrs. Park Ward. We should appreciate your approval for this modification to be adopted on all 'Wraith' chassis. The matter is rather urgent and we suggest that you give this your earliest attention. Finally it must be stressed that this does not correct the cause of the trouble, which can only be done by redesign of the engine mounting brackets. | ||