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 Automotive Industries clarifying the calculation of shipping weights and effective tire diameters for American passenger cars.
| Identifier | ExFiles\Box 142\1\ scan0305 | |
| Date | 14th December 1938 | |
| N.R.C file. Statistics 1204 A CHILTON Publication Automotive Industries CHESTNUT AND FIFTY-SIXTH STREETS • PHILADELPHIA • PA{Mr Paterson} December 14, 1938 Rolls-Royce, Lrd. Experimental Department Derby, England Ref - Rm{William Robotham - Chief Engineer}/NRC.{N. R. Chandler}19/JH Gentlemen: This is in reply to your letter of December 2nd regarding the shipping weights of American passenger cars as they appeared in our November 12th issue. For your information shipping weights usually includes the net weight of the car with tool kit and such equipment as covered by delivered price at factory. However the car is drained of gasoline and water and contains less than capacity of oil. The figure we showed was used to calculate the "Weight per Cubic Inch", "Weight per Horsepower" and after adding 400 pounds was also used for obtaining the "Displacement factor". No doubt the reason you were unable to check back on the formula for the "Displacement Factor" and secure the shipping weight was due to the "effective tire diameter". Effective tire diameters are secured from the tire manufacturers direct and are considerably different from a calculated tire diameter. For instance a 6.00/16 tire we would assume to have a 28 inch diameter, but the effective tire diameter in reality is only 26.80 inches. We appreciate your interest in our specification tables and sincerely hope that, if there are any other questions, you will feel free to write us. Very truly yours, Marcus Ainsworth Statistician AUTOMOTIVE INDUSTRIES Marcus Ainsworth ww | ||