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 efficiency and condition of a silencer system after testing.
| Identifier | ExFiles\Box 66\2\ scan0017 | |
| Date | 10th February 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF HS{Lord Ernest Hives - Chair}/ACL/LG10.2.25. very efficient and practically the same power output is obtained as with open exhaust. The 'open exhaust' curve given is correct for the loss due to temperature of hot spot. It is seen that the total loss in power with the cutout closed is practically due to the sum of the losses caused by:- (a) The swan neck unit - and (b) The small holes in the intermediate pipe. Also the small holes in the intermediate pipe give a greater loss than the swan neck unit. The loss due to the baffles in the interior of the silencer is very small as can be seen from the curves. From our experiments it seems that these two chief losses (a) and (b) could be reduced without impairing the efficiency of the system as a silencer. The greatest promise seems to lie in increasing the size or number of holes in the intermediate pipe and perhaps decreasing those in the baffle plates contained in the silencer. CONDITION OF SILENCER AFTER TESTS :- When running full throttle with the cutout open, the butterfly valve very quickly reached a high temperature - bright red. The torsion springs lost their temper and would not close the valve. The butterfly spindle distorted and this apart from the failure of the rpk springs, made the valve hard to close. It seems necessary that these parts should be made more robust and perhaps the springs placed in such a position that they are insulated from the heat. contd :- | ||