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).
Improvements to the Goshawk model, including a 4-speed gearbox, front brakes, and a strengthened crankshaft.
| Identifier | ExFiles\Box 6\4\ 04-page018 | |
| Date | 8th December 1924 | |
| To C.J. from R.{Sir Henry Royce} c. to BJ. HS.{Lord Ernest Hives - Chair} c. to PN.{Mr Northey} BY.{R.W. Bailey - Chief Engineer} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} X5310 GOSHAWK 4. R3/M8.12.24. X.5310 X.5770 This is the improved Goshawk with 4-speeds and side levers, the box of which has just been completed and is on test. It is to be fitted with front wheel brakes, the designs for which are almost completed, the front axle being for some time in the hands of Derby, the servo is just about to leave WW. the pedals have been pushed forward to give slight economy in dimensions which has been rendered possible owing to the changes made in the gearbox. The frame for this model is to have the joggle slightly further back and the front springs are to be lengthened and the car fitted with a light proportion of front wheel braking, but without radius rods, unless these are found necessary, but in any case the front axle is prepared so that they can be fitted. [struck-out text] The rear brakes are to have the wider straps suggested by Derby for the foot brake, the hand brake straps remaining the present width. The engine is to be fitted with the strengthened crankshaft to the following dimensions :- The dia. of the journals will be 2.150, and the length of the intermediates 1.150. The crankpins are to remain 1.5 dia. by 1.5 long. The pattern and the jig for the crankchamber are not to be altered but the bearing designs are to be modified by fitting steel housing with flanges so that the dowel pins can be deleted and none of the bearing surfaces cut away in the middle of the bearings where the maximum load from centrifugal force and explosive pressure occurs. The two end bearings and the centre bearing to have 3 oil holes about .150 dia. arranged to give 120° of plain surface at the point of maximum centrifugal load. I consider the oil holes are at present in the wrong position: although correct for explosive pressures, they are very wrong for maximum centrifugal loads. In fitting this improved crankshaft we are adopting the wide oval, .75 thick, minus clearances. There is also an improved oil retainer to be fitted to the flywheel end of this crankshaft, (EAC. type). If possible other improvements are to be fitted to this engine so that it will give 60 HP. They consist of the exhaust divided into 2 threes, with a [struck-out: max] cutout at the back end of the silencer, consisting of a well fitted single butterfly. R.{Sir Henry Royce} | ||