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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).
Letter detailing vehicle test results and required improvements after a run from Dieppe.

Identifier  ExFiles\Box 108\1\  scan0332
Date  11th February 1938
  
600a

11.2.38

COPY OF LETTER RECEIVED FROM RM.{William Robotham - Chief Engineer} Feb.8th.1938

26.G.Vl.{V. Lewis / Mr Valentine}

We had a good run from Dieppe. The points that want attention on the car, and which must be worked on at Derby are:-

(1) Oil consumption is only 500 M.P.G. Check over any cars with up-to-date engines at Derby. What was the test bed oil consumption of this unit on the test bed.? Curiously enough the oil leak from the rear main bearing is negligible.

(2) Petrol consumption when driven hard gets close to 10 M.P.G. Check specific consumptions on the test bed and compare with the standard 25/30, driving one car behind the other.

(3) Engine vibrations. Allnoticed at Derby prominent out here, particularly those brought up under load. The roughness above 70 M.P.H. is bad. We shall have to continue our investigations.

(4) Suspension. For some reason the governor control is now behaving sensibly and the damper loads are a good compromise even for Continental conditions. It is obvious that, with a full load, the rear tyres are over loaded and a front roll rod is wanted. We must try it out with the very soft springs Les.{Ivan A. Leslie} is getting. We might make it a standard fitting for Continental cars.

(5) Axle Ratio. Owing to the vastly improved handling, the car can be driven far harder than the 25/30. and I want to persuade Hs.{Lord Ernest Hives - Chair} and Sales to agree to a higher axle ratio. Presumably we can fit a 4.25 ratio using the P.III. gears. Anyhow, stop Production cutting any number of gears until we have discussed this with Sales.

(6) Brakes. Seem alright with the reduced front braking.

(7) Steering. There is still a tendency to column shake which is almost certainly due to the front engine mounting. It is not bad enough to stop production.

We have had perfect weather and snow so far.

I shall be in Paris on Wednesday and return to Derby on Thursday, back at the Works Friday morning. I shall try the Bentley before I return.

Rm.{William Robotham - Chief Engineer}

The B.50 axle gears we are ordering should not be lower than a 4.35 ratio.
  
  


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