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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).
Test report discussing engine mounting, torque reaction dampers, and vibration issues on experimental cars 24-EX and 25-EX.

Identifier  ExFiles\Box 11\3\  03-page390
Date  4th July 1931 guessed
  
(3)

dampers as test (2). This setting was found to be the most satisfactory for 24-EX. Owing to the flapping of the front wings at torque reaction speeds.

With this engine mounting we have brought torque reaction almost out of the driver's range, but we feel we should point out that it is now at a very likely speed for an engine to be running in neutral whilst the passengers alight. A vibration period can be felt all over the car at this engine speed.

When 25-EX was in England with the final settings for the torque reaction dampers, the movement of the wings at 9.5 m.p.h. was almost negligible. Directly we arrived in France the wings began to flap. This we think must be due to the change in petrol as extra detonation was also noticed.

Pedal Movement. This we do not think is really likely to become objectionable to the driver. The passenger in the front seat would have the greater cause to complain, as from his seat the movement of the gear lever can be recognised as a relation to that of the pedal movement, and might give the impression that something had come adrift. The pedals tickle the driver's feet less than the canti-lever supported pedals on 24-EX.

When the torque reaction dampers are set at our advised setting, the car is not actually free from booms, although there is not sufficient for a customer to complain. Tightening the torque reaction dampers to solid made wonderfully little difference to booms, although an increase was recorded. It is however only fair to expect a diamond mounted engine with torque reaction dampers solid to be as good if not better than a present standard car with rear engine feet removed. We realise that 25-EX at one time with rear engine feet removed was fair far from being free from booms, but later however it forgot how to boom, and this was accounted for by distortion of the body. We therefore feel it is at present unnecessary to arrive at a more accurate setting for the dampers, as 25-EX may still not be one of our worst example of booms.

Hs{Lord Ernest Hives - Chair}/Les.{Ivan A. Leslie}

I. A.{Mr Adams} Shorlie
  
  


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