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).
The comparative efficiency tests of EAC and 40/50 steering columns.
| Identifier | ExFiles\Box 67\3\ scan0080 | |
| Date | 15th February 1925 | |
| To. Hs{Lord Ernest Hives - Chair} From RHC.{R. H. Coverley - Production Engineer} C. Ver. C. BY.{R.W. Bailey - Chief Engineer} ------------- 48430 RHC{R. H. Coverley - Production Engineer}1/BE. 15.2.25. ---------------- RE STEERING EFFICIENCY TESTS. We have carried out Tests to find out the comparative efficiency of EAC & 40/50 Steering Columns. These were rigged up on a bed under car conditions( see Sketch.Fig.1). A Spring Balance was connected up to Pendulum Lever to a registered load and a grooved Steering wheel was used for the purpose of taking INPUT load. It might be assumed from the sketch that we should get a certain pullover on the top of Steering Worm when applying the INPUT load, but we took the precaution to balance the load by using 2 Spring Balances,but we found out this made no difference, so we carried on our Test with 1 Balance. We can therefore, safely say the pullover does not affect results. In going over the figures for the INPUT & OUTPUT efficiency it might be considered that the difference between EAC & 40/50 is very slight, but it must be borne in mind that the ratio of EAC is different to 40/50. 40/50 has a 3 start worm against EAC 4 start. The latter should give approximately 25% increased efficiency, which apparently is lost in the Box. The first Test on the EAC Column was to ascertain what deflection took place on the Steering Box, and the maximum load applied was 650 lbs on the Pendulum Lever. This is the load we understood that the Steering is subject to when locking over with car stationary. The deflection measured was from .002 to .005. We have got all these figures, but are not sending them along because we thought they would not be of so much interest to you. We also carried out a test with a Bracket supporting the inside of Steering Box, and with this, all measurable deflection disappears, so it would appear that it would be advantageous to have some form of support for the Steering Box. The design of 40/50 and EAC Steering is very different. The Rocking Shaft on 40/50 Steering is balanced with 2 Ball Races, therefore any slight deflection in the Box can be accomodated. On the EAC we have a long plain bearing and a short bearing, and any distortion on the Box would increase the friction in these bearings. BY has issued certain instructions under L.F.554(copy enclosed) and by this it will be seen that he has aimed at getting a properly balanced support for Rocking Shaft. We have not finished these parts yet, but we shall carry out the same tests with these as on the other Steerings. We also tested the EAC Roller Bearing Column and whilst this shows up better than the plain bearing type, there are certain losses in efficiency when locking over. We found on this Column that if the wheel was locked over quickly, the load went up considerably, which tends to prove that the Rollers wind and jamb. This appears to be the result of a cage -contd- | ||