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 The Retrac Co. discussing the benefits and trial of their oil spring shock absorbers.
| Identifier | ExFiles\Box 46\1\ Scan128 | |
| Date | 3rd June 1919 | |
| TELEPHONE MURRAY HILL 3952 X4131 THE RETRAC CO. OIL SPRINGS PATENTED 52 VANDERBILT AVE. COR. E.{Mr Elliott - Chief Engineer} 45TH ST.{Capt. P. R. Strong} NEW YORK, N.Y. June 3, 1919 A.{Mr Adams} Wormald, Esq., Rolls Royce Company, Derby, England. Dear Sir: At your Mr. Caswell's request I am delivering to your New York Service Station a set of Oil Springs which I understand he is forwarding to you for trial. I have developed these shock absorbers, using one of your cars which I have owned since 1912, and also with a special experimental car equipped both front and rear (cantilever) with your springs. I have also equipped quite a number of your cars which are in service in this country today. Broadly speaking I believe the function of this attachment is to make it practical to use springs of high flexibility with soft spring action allowing them practically free action on good road conditions but reinforcing their action in a progressively increasing manner as the road conditions become worse. From experience with your cars which I have equipped I have found that in order to give the best results over our road conditions that it was possible not only to make use of the flexible springing ordinarily attached for European driving, but even to equip both front and rear with springs from 150# to 200# lighter than your European standard. I hope that in trying out the Oil Springs that you will consider the above points, as I believe you will find it possible to use more flexible springs than are the present standard for a given weight of body and passengers, so that less difference will be noticed in the comfort of the car with a variation of passenger or equipment load. Simply as a suggestion I believe that for American road conditions you will be able to obtain better riding either with or without the Oil Springs, provided the front spring design was changed to give 1" more free clearance between front spring and bumper. (The Crane Simplex have a clearance of 4 3/4" using a flat front spring). Our road conditions are such that with the present small clearance in front it necessitates using springs of less flexibility in front (consequently with a period which does not properly co-act with the rear springs) in order to prevent striking. | ||