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).
Modifications to a 40 HP Laurence Scott Dynamometer for improved accuracy.
| Identifier | ExFiles\Box 143\1\ scan0233 | |
| Date | 3rd February 1937 | |
| 1209 EJJ/JV from Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards} Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards}16/M.3.2.37. 40 HP. Laurence Scott Dynamometers. With reference to the above dynamometer at present in use on No. 4C bed on the S/C Bentley Unit, we should like to raise the following points:- (1) The constant for the brake is WN/2500 obtained from an effective radius of 25.22" and giving an m.e.p. constant of 8 5 (2) The balance used goes up to 50 lbs. and as the load seldom exceeds 15 lbs., almost super accuracy in reading and setting is required if serious errors are not to be introduced. The following suggestions are, therefore, made and we should be glad if you would put them in hand as soon as possible. (1) The brake constant be altered to WN/3500 which can be done by decreasing the effective radius to 18.03". This can be easily done by shortening the arm on the dynamometer, which as it is of welded construction can be cut and re-welded to the correct size. Also the supports for the brake balance can be moved inwards by making a flat plate and drilling to suit. If this radius should prove too small, then WN/3000 could be employed, which would call for a radius of 21.62" (2) A 25 lb. balance should be employed, necessitating a balance weight of 17.1 lbs. The attachments are as for the existing balance, but a scale divided into 1 lb. units subdivided into 0.1 lb. and 12" dia. in place of the existing 9" It is anticipated that these modifications will double the accuracy of the brake, and as they are all very simple we see no reason why they should not be done by ourselves. Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards} | ||