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).
Technical memorandum discussing the factors for and against using a removable sub-frame.
| Identifier | ExFiles\Box 117\2\ scan0342 | |
| Date | 12th April 1940 | |
| Rm{William Robotham - Chief Engineer}/GB.I/JH.12.4.40 - 2 - does not involve the payment of increased insurance premium. It is reasonable to suppose from this that the lack of a detachable sub-frame does not increase the cost if repairing collision damage. Other factors to be taken into consideration in deciding for or against a removable sub-frame are:- (1) Effect on overall stiffness. (2) Silencer & (3) Ease of Assembly. (1) Overall stiffness - The Vauxhall & Morris tens have the same torsional rate, axle to axle. Good stiffness can be obtained with either type of assembly. (2) Silence. - A bolted sub-frame is unlikely to reduce noise unless rubber is interposed between the body and the sub-frame. The use of rubber here has been accompanied by a serious reduction in stiffness. Dash to floor details and axle and engine mountings all affect noise more than permissible variations in the sub-frame fixing. (3) Ease of Assembly - For economical assembly of chassisless cars, the main units have to be resting on the track in predetermined positions by the time they meet the body. Although a separate sub-frame affects the arrangements of the components it is doubtful if it simplified the operation. A removable sub-frame does concentrate loads at the attaching bolts and both the body and the sub-frame require local strengthening. To sum up, there are no outstanding advantages to be gained by the use of a detachable frame extension. Equally There are no outstanding advantages to be gained by the use of a fixed extension. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} BASTOW. | ||