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).
Test report on the Goshawk 11 rear brakes, detailing dynamometer performance, failure of aluminium shoes, and material comparison.
| Identifier | ExFiles\Box 180\M1\1\ img050 | |
| Date | 1st October 1921 | |
| F.R. 235a (100 T) (Spg?) 10-12-20 ?? Ms. c. to CJ. c. to R.{Sir Henry Royce} c. to Da.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} c. to KP. c. to Wor.{Arthur Wormald - General Works Manager} ORIGINAL. hsl/LCS.10.21. Goshawk 11. X1257 X4253 X4259 X4282 REAR BRAKES. We have tested the rear brakes of this car on the dynamometer in a similar manner to how the 40/50 H.P. rear brakes were tested. With the foot brake we ran 5 minutes absorbing 15 H.P. At the end of that time the drum was red hot - at the end of the test the brake was still effective. The clearance between the brake and the drum remained fairly constant throughout the test. At the commencement the pedal went down nearly to the floor boards but when the heat had got through to the shoes it came back again and remained constant. We carried out the same test on the hand brake. *After 5 minutes running with the hand brake however, this brake failed.* We found on examination that the aluminium shoes had broken on both sides. The alloy used for these shoes was crankcase alloy. One would imagine they would be better in piston alloy. We feel that most probably with the aluminium brake straps it might be necessary to countersink the heads of the rivets so that they do not rub on the drums and so that they cannot transfer the heat into the brake shoe. On the 40/50 it was found a definite advantage to have the rivets rubbing so that there was fairly equal expansion on the brake drum and brake straps. We are sending on the broken brake straps to Mr. Royce. *The 40/50 foot brake has been tested for Half-an-hour absorbing 27 H.P.* contd:- | ||