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).
Dynamometer testing of a gearbox with Cadillac gears, focusing on heat generation and temperature limits.
| Identifier | ExFiles\Box 94\2\ scan0168 | |
| Date | 6th February 1937 | |
| FILES Y 1052 6.2.37. P.3. GEARBOX CADILLAC GEARS. During our recent dynamometer testing we noticed that a box with Cadillac gears ran hotter than one with R.R. gears, or that after our decision to limit the box temperature to 130°C. we could run longer on R.R. gears than Cadillac gears before changing to cold oil. we thought at first that this might be due to the increased oil churning of the larger Cadillac teeth. Starting with a cold box we took a temperature time curve running light in top gear (rear wheels jacked up) at 50 M.p.h. This shewed no difference between the boxes, both attaining 90C assymtotically after 90 minutes. we next took time temperature readings from cold running full throttle in 3rd. gear with results as shewn on the attached graph. we think the increased heat generation of the Cadillac gears is due to the higher bearing loads due to the increased spiral angle of the gears. By estimation from a cooling curve with the assumption that the box is equivalent to 30 lbs. of water the Cadillac gears appear to generate 3/4 HP. more heat. we do not consider this sufficient to justify abandoning them. Rm{William Robotham - Chief Engineer}/ Gry.{Shadwell Grylls} | ||