Rolls-Royce Archives
         « Prev  Box Series  Next »        

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 from Ferodo discussing the failure of 'Cotton A' servo motor linings and proposing 'Ferodo S. 3914' as a replacement.

Identifier  ExFiles\Box 141\3\  scan0216
Date  3rd October 1933
  
X 719
All Communications to be addressed to the Company.

FERODO LIMITED

TELEPHONE: 19 CHAPEL-EN-LE-FRITH (4 LINES)
TELEGRAMS: FRICTION, PHONE, CHAPEL-EN-LE-FRITH.

FERODO
REGD. TRADE MARK
BRAKE & CLUTCH LININGS

CODES: WESTERN UNION FIVE LETTER EDITION, BENTLEYS COMPLETE & 2ND PHRASE, MARCONI INTERNATIONAL, LIEBER'S CODE, LIEBER'S LATEST CODE, A.B.C. 5TH & 6TH EDITIONS.

CHAPEL-EN-LE-FRITH,
VIA STOCKPORT, ENGLAND.

October 3rd 1933

YOUR REF. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}8/KT
OUR REF. FJF/WAC.

Depots:-
LONDON
2, TOTTENHAM COURT RD W. 1.
ABERDEEN
26, GUILD STREET.
BELFAST
8, 10 & 12, MONTGOMERY ST
BIRMINGHAM
202, CORPORATION ST
BRIGHTON
84, QUEEN'S ROAD.
BRISTOL
19, PARK STREET.
CARDIFF
39, CHARLES ST
DUBLIN
120, UPPER ABBEY ST
GLASGOW
WATERLOO ST
LEEDS
25, HUNSLET RD
LIVERPOOL
1-3, BERRY STREET.
MANCHESTER
32, CATHEDRAL ST
NEWCASTLE-ON-TYNE
WORSWICK CHAMBERS, 10, WORSWICK ST OFF PILGRIM ST

Messrs. Rolls-Royce Ltd.,
Experimental Department,
Derby.

For the attention of Mr. S.W.Grylls.

Dear Sirs,

We thank you for your letter of the 28th ultimo and assure you that we appreciate the requirements of the lining for your servo motor, and are quite prepared to continue investigating until we are in a position to say either that we can go no further or are able to offer the type of material you are looking for.

Certainly we will send you another pair of Ferodo S. 3914 discs, of which we may say that it is reasonably consistent even if slightly on the low side, but in view of your willingness to modify the angle of the cam, Ferodo S.3914 may possibly meet the requirements.

Referring to the linings "Cotton A", our experience of these has been rather unfortunate for, after running at a very low speed for less than half a minute, the servo started to judder and groan, conveying the impression that the whole arrangement was undergoing a process of disintegration. Dismantling the servo, we found the linings had adhered to the metal parts; the small pins used to prevent the outside lining moving against the aluminium cover plate were torn out and cut a shallow groove in the outside face of the outside lining, as you will see on receipt of the parts we are sending to-day by post.

The writer gives his personal assurance that the maximum temperature reached during the short period of application did not exceed 180° F, but it would appear that even this moderately low temperature was sufficient to cause exudation of the impregnant used in the material in question.

You will note the discolouration of the inner portion of the metal part, but this evidence of elevated temperature was produced long before "Cotton A" linings were used - in fact, this incidence is entirely disassociated with that lining.

Will you be good enough to return the metal parts in order that we can make further tests of material somewhat
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙