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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).
Report page detailing engine detonation tests, percentage power loss figures, and valve timing settings.

Identifier  ExFiles\Box 134\1\  scan0055
Date  13th December 1937
  
-4- Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards}9/AP.13.12.37.

III. DETONATION cont'd

The ignition being retarded in each case until detonation was only just audible. As will be seen the power for No.5. head is only slightly below that for No.4. head, in approximately the same proportion as when comparative curves on a non-detonating fuel were run. Figures are as under:-

PERCENTAGE POWER LOSS WITH RESPECT TO NO.4.HEAD

R.P.M. 1000 1500 2000 2500 3000 3500 4000

Max.power 3.6% 2.1% 1.1% 1.6% 2.6% 3.4% 1.7%
(Non-detonating
fuel)

No detonation. 2.0% 1.7% 1.8% 1.0% 0.4% -0.2% -0.4%
(Paraffin-shell)

It should be noted with regard to the above figures that different valve timings were used, the maximum power figures running on I.O.2°E.{Mr Elliott - Chief Engineer}, I.C.28°L., E.O.51°E.{Mr Elliott - Chief Engineer}, E.C.7°L., as being a best average valve timing, and comparable with all previous results, and the non-detonating curves on I.O.TDC., I.C.30°L., E.O.35°E.{Mr Elliott - Chief Engineer}, E.C.TDC. to give maximum low speed power with the greatest tendency to detonate.

IV. VALVE TIMING

Three different timings were used throughout these tests as under:-

(1) I.O.2°E.{Mr Elliott - Chief Engineer}, I.C.28°L., E.O.51°E.{Mr Elliott - Chief Engineer}, E.C.7°L.

This gave a good average power curve and as most of the previous results were run with this timing, tests were done on No.5. head for comparative purposes.

continued
  
  


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