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).
Experimental instructions for 'S.S. Hot Spot' testing and a performance upgrade program for a 20 HP engine.
| Identifier | ExFiles\Box 13\3\ 03-page110 | |
| Date | 16th October 1929 | |
| To CHP. from Hs{Lord Ernest Hives - Chair}/ACL. c. LNS. c. GP. *7080. Hs{Lord Ernest Hives - Chair}/ACL2/AD16.10.29. x7080. x7230 x5680 x5230, S.S. HOT SPOT EXPERIMENTS. (1) Make up two sets of thermo couples which can be used on car or test bed. (2) Run complete hot spot system with free outlet from the hot spot and obtain :- Power, Temp. and remarks on any tendency to detonate at low speeds. (3) Repeat above with hot spot either cold or just sufficient heat to give good distribution. Compare with (2) for power, loss, detonations etc. (4) Test of alum. hot spot can be damaged due to excessive heat at full throttle with open ended exhaust from hot spot. (5) Make up an exh. butterfly baffle and see the amount needed to be closed to maintain reasonable temp. at full throttle so as not to appreciably lose power. 20 H.P. PROGRAMME (1) Increase passage through cylinder block as much as possible (a) larger bore (b) cut down lower part making the passage oval. (2) Increase both inlet and exhaust valves as schemed on V.{VIENNA} drawing making both inlet and exhaust the same size. (3) Slightly enlarge ports. (4) Use the larger 20 H.P. carburetter. (5) Increase com. ratio to 5.3/1. (6) Use long durn camshaft (116°). (7) Put in hand a larger bore exhaust manifold. | ||