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).
Weak point in a frame with springs anchored at the rear, proposing a stiffener design for further testing.
| Identifier | ExFiles\Box 119\2\ scan0186 | |
| Date | 13th March 1924 | |
| To HS.{Lord Ernest Hives - Chair} and BY FROM DA.{Bernard Day - Chassis Design} /1331 SECRET. DA{Bernard Day - Chassis Design}1/M13.3.24. EAC.111. FRAME WITH SPRINGS ANCHORED AT REAR. X.9410 X.9380 X.1331 With reference to Mr. Hives' report of the result of bumping, and the section of the frame which we have received this morning, we agree that there is a weak point here. The stress from the fully bumped load of the spring looking upon this part of the frame as a cantilever is about 20,000 lbs. per sq.in. on this section and the crushing load in the tiebar bolts may be very high, say 50,000 lbs.per.sq.in. In addition to this there is local buckling of the thin metal of the frame between the spring bracket and the tiebar bracket and another buckling due to the side load on the spring brackets. We propose to design a stiffener which includes the tierod bracket, and shall send you a scheme and further suggestions immediately. In the meanwhile we presume that in accordance with Mr. Hives' report he is now building up a frame for further testing. If this is so we suggest that it should not be exactly like the one that broke. In the first case this one seems to have only 3 bolts in the tiebar bracket. On N.Sch.1717., we moved the tiebar bracket back in order to get 4 bolts in. We should like this to be done at least. We hope to be able to get away our sketches to you either tonight or tomorrow, and as to whether you proceed to bump a frame as above, or wait for our sketches, is a matter for you to decide but we think the frame will break again even if arranged as above. DA.{Bernard Day - Chassis Design} | ||