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 discussing sample belts and pulley specifications for parts EB-221 and EXS.194, with engineering recommendations.
| Identifier | ExFiles\Box 135\1\ scan0136 | |
| Date | 4th March 1938 guessed | |
| Rolls-Royce, Limited Page 3 Subject: Part EB-221 We are sending you three sample belts for this application with the following dimensions: Top Width--.760"; Thickness--.437"; Angle--46 degrees; and OC--43 1/4". We want you to machine special grooves in your pulleys for this belt, and the groove should be of the following dimensions: 11/16" Top Width; 11/16" Deep; 38 degree angle. Subject: Part EXS.194 We are sending you a belt for this application with the following dimensions: 1.090" Top Width; .562" Thickness; 44 degree angle; and 42-3/4" OC. Again we want you to remachine the grooves for this application to this size: 15/16" Top Width; 15/16" Deep; and 34 degree angle. We are sending you two test belts for this application. Now to be very honest with you, I am going to repeat what I said before. You are expecting a great deal, a very great deal, from a fan belt on this application. I believe these belts we are sending you will do a better job than any you have tried before, but even so they may not live up to all that you wish. Our Engineering Department feels that you would have a far better chance on both of these drives if you could increase the belt speed by using larger sheaves. Of course, we don't know if you have room for these sheaves on the motor, but if possible we would strongly recommend you to use 6" or larger sheaves on Part EB-221 and 7" or over sheaves on Part EXS.194. Both of these dimensions are given in outside diameter. If it is possible for you to use these larger sizes, let us know, and also let us know the center distance on these two drives, and we will be glad to submit a new belt for both applications, if you would like us to. But it is particularly important, Mr. Steadman, that you let us have the center distance on both these drives, if you are able to enlarge the sheaves. The sample belts we are sending you are being made specially, so they will not be ready to leave here for a few days. However, you can count on us showing all haste possible in getting them off to you. It is unfortunate that they are not a standard size, as we could then cable our distributors over there and have them supply you from the large stock they carry. However, we will just have to be patient, I suppose. When we succeed in supplying thoroughly satisfactory belts for you on both of these applications, we intend to see that our representative carries a stock of them for replacement purposes. Needless to say, Mr. Steadman, we are taking more than a usual interest in your problem, and we will be looking forward to hearing from you as soon | ||