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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).
Technical memorandum discussing the potential causes of servo judders on vehicle 35-EX.

Identifier  ExFiles\Box 92\3\  scan0131
Date  27th February 1937
  
W/S.
To Sg.{Arthur F. Sidgreaves - MD} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}
c. to Cx.{Major Len W. Cox - Advertising Manager}

300a.

Rm.{William Robotham - Chief Engineer} Absent.
Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}4/AP.27.2.37.

Re. 35-EX.

We do not think that the servo judders could possibly be attributed to any of the items Nos.15, 17, 19 or 20 mentioned in Rm.{William Robotham - Chief Engineer}'s specification Rm.{William Robotham - Chief Engineer}11/AP.29.1.37. The machine rivetted brake linings with copper rivets are a reversion to Ph.II. practice and overcame the trouble experienced with brass rivets. The R.R. cast iron brake drums merely mean that we make the drums in this Factory.

The increased hand brake travel is to make it easier to hold the car on a gradient by means of the hand brake. The increased front brake travel is simply the deletion of a foul which on early cars prevented full use of the front brakes, owing to a lever coming down on top of the pivot.

We think the cause of the judders is an undue stretching of the rear brake ropes caused by failure of the shock absorber links. The fact that these ropes did stretch is mentioned in Hancock's report of Feb. 22nd at a mileage of 6073. Another possible explanation is collapse of the servo star springs, to overcome which, as mentioned in Daily Report of Feb.24th., the washer between them as been reduced.

The car should have finished 10,000 miles by this week-end; as Hancock will then have two Bentleys to keep his men occupied, 35-EX. is going to the Paris Depot for the stiff half shafts to be fitted. At the same time they will experiment on the road holding, with and without rubber shackles.

Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}
  
  


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