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).
Weight limit variations and specifications for Goshawk II rear springs.
| Identifier | ExFiles\Box 49\3\ Scan109 | |
| Date | 19th May 1922 | |
| y4261 BY4/H. 19. 5. 22. Mr. Booth. Wd. {Mr Wood / Mr Whitehead} c. Hs. {Lord Ernest Hives - Chair} RECEIVED GOSHAWK II. REAR SPRINGS. X4261 ------------------------- In looking over these drawings I note that we have specified as weight limit variations, +50 -50 lbs. which is the same variation that is allowed on the 40/50. I am certain that this amount is far too great and that the spring makers should work within a limit of + 30 -30 without difficulty. It is quite obvious that in taking this limit from the 40/50, we have made a distinct error, and that in carrying the limit down to -50 lbs. we are only imposing a reasonable limit in relation to the weight on the spring and the deflection of same, which in the case of the 40/50 are a 3" deflection against 1500 lbs as the lightest spring and in the case of the Goshawk, a 5 1/2" deflection against 700 lbs. There is one other factor which also demands consideration, namely, the fact that we have only got a range of three rear springs on the Goshawk, 700, 800, and 900 lbs. to cover all customers' requirements; I think a step of 100 lbs when the deflection of the spring under this amount is taken into consideration is probably too great, and that it would be more reasonable to have a range of five springs, giving 700, 750, 800, 850, and 900 lbs. loading capacity respectively with the above limit of variation on the load. For the present, however, we will try whether we can, with the limits specified, select springs to meet customers' requirements and keep within reasonable height variations between the ground and the top of the frame. The only factor which deters me from, at once going to the larger range is the increase of cost, and one would like, therefore, for the present to try the range of three specified weights as the limits should apparently give us springs within + or - 20 lbs of anything which might be called for. This assumes that we get some springs of each type on both the high and low limits. BY. {R.W. Bailey - Chief Engineer} | ||