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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).
Summary of test results and conclusions on engine performance, detonation, and power output.

Identifier  ExFiles\Box 134\2\  scan0195
Date  1st February 1939
  
-8-

Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}2/MH.{M. Huckerby}1.2.39.

Summarising the results of these tests the following conclusions are made.

(1) The larger the throat area the better the maximum and non detonating power, to quote, 6.8 : 1 compression ratio with 1.64 sq.in. gives 122 Max and 119 non detonating MEP at 1500 r.p.m. against 6.25 compression ratio with 1.75 sq.in. giving 125 Max. and 125 non detonating MEP at 1500 r.p.m.

We consider therefore, that the throat by redesign could be further increased with advantage.

(2) Extended combustion chamber and reduced sandwich area, i.e. with normal flat topped piston is disastrous, therefore the design should go the opposite way to give a more compact combustion chamber and an increased sandwich area.

(3) The thinner this sandwich of gas between the piston and cylinder the better the non detonating power obtained.

(4) As will be noted we have no value for the sodium filled exhaust valves but the comparison with solid valves will be obtained as soon as possible.

(5) Whenever a condition of bad detonation is run, the gaskets burn through in approximately one test curve, but in our up to date condition we have run 50 hours endurance without trouble in this respect. Incidentally, any burning is coincident with the weakest mixture cylinders.

POWER.

The power curve shown on the curve Rm.{William Robotham - Chief Engineer}581 indicates that under the same conditions, B.V. induction system and 6.5 : 1 compression ratio the maximum power of the B.60 and B.V. units running open exhaust is almost identical. At the middle and low speeds, however, the B.60 is appreciably better than the B.V. both for maximum and non detonating MEP.
  
  


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