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).
Parking efficiency figures for different steering nut and worm leads.
| Identifier | ExFiles\Box 17\4\ Scan066 | |
| Date | 7th December 1933 | |
| X7U30 To RHC.{R. H. Coverley - Production Engineer} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Ra.4/KT.7.12.33. STEERING NUT & WORM. Thank you for your RHC.{R. H. Coverley - Production Engineer}1/AP.6.12.33. Actually I am afraid I worded my hand written note rather badly. You will see from the extract from Hs{Lord Ernest Hives - Chair}/Rml/LG22.3.28 that we got a parking efficiency of the .940 lead to be 66% which conforms very closely to your mean figure which is about 68%. The figure which seems to be unduly high is that for the standard .720 lead which originally we got to be only 58% efficient, while your figures make it something over 80%. We should be interested to have an average figure for a number of .720 leads at present going through production. If this figure consistently comes out more than the .940 it will be apparent that the different construction of the .720 lead and its greater area is the predominating factor and not the helix angle. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||