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).
Shear stress and required size of rivets for the 3.5 litre Bentley chassis fan.
| Identifier | ExFiles\Box 86\5\ scan0015 | |
| Date | 12th January 1934 | |
| X224 To By.{R.W. Bailey - Chief Engineer} from E.{Mr Elliott - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} Mx.{John H Maddocks - Chief Proving Officer} E.5/HP.12.1.34. 3.5 litre Bentley Chassis Fan. Referring to your memo By.6/G.5.1.34, I find that the rivets securing the blades used on the fan fitted to the 10,000 mile Bentley were .187" diameter, whereas the rivets used for this purpose on production fans are .125" in diameter. I have had some figures taken out which indicate that the shear stress in the rivets of .125 diameter at a speed corresponding to 4500 engine revs is 16,000 lbs.per sq.inch on the assumption that all rivets are carrying an equal load. Actually, of course, there is sure to be some inequality in load distribution. I think we should at once increase the size of the rivets to .187" and we shall have to come to some decision as to whether it will be necessary to change all fans fitted with the smaller rivets. E.{Mr Elliott - Chief Engineer} | ||