Analysis of rear axle stresses for a P.2 engine in a J.3 chassis with various gear ratios.
| Identifier | ExFiles\Box 123\3\ scan0007 | |
| Date | 2nd May 1933 | |
| BY. {R.W. Bailey - Chief Engineer} from Da. {Bernard Day - Chassis Design} c. Sg. {Arthur F. Sidgreaves - MD} Wor. {Arthur Wormald - General Works Manager} Hs. {Lord Ernest Hives - Chair} E. {Mr Elliott - Chief Engineer} Copy X DA. {Bernard Day - Chassis Design} 1/G.2.5.33. P.2. ENGINE IN J.3. CHASSIS - REAR AXLE. If the engine is the 8.1 litre Phantom and the rear axle the existing J.3. with a 4.1 axle ratio, the stresses are as follows, with those in the Bensport(Codename for 3 1/2-litre Bentley) which broke placed alongside for comparison - lbs. per sq. in. In the Hypoid Gears. | In the Differential Gear. | In the axle driving shafts. P.2. J.3. | Bensport(Codename for 3 1/2-litre Bentley). | P.2. J.3. | Bensport(Codename for 3 1/2-litre Bentley). | P.2. J.3. | Bensport(Codename for 3 1/2-litre Bentley). 174500 | 135500 | 187700 | 191500 | 69500 | 54600. We think that the J.3. axle in conjunction with this engine is rather near the limit. If we use an 11/41 ratio on the J.3. axle (same as P.2.) of which a drawing exists, the following are the stresses :- In the Hypoid Gears. | In the Differential Gear. | In the axle driving shafts. 158000 | 170000 | 63000 These may still be thought to be high, and we suggest providing a gear ratio higher than standard P.2.(11/41). This seems to be justified by the following figures:- | Weight cwts | Engine cc. | Axle Ratio. | Wheel Rad | Max Eng. RPM | Max MEP. | Accel'n fig.of merit engine cc.x axle ratio x MEP. Wt x wheel Rad. | Max MPH. at MAX. Engine speed Bensport(Codename for 3 1/2-litre Bentley). | 30 | 3669 | 4.1 | 14.5 | rpm | 115 | 39.8 | P.2.Stan. | 48 | 7668 | 3.72 | 15.5 | 3500 | 110 | 42.2 | 86.8. P.2.J.3.11/41 | 43 | 8100 | 3.72 | 15 | 3500 | 110 | 51.6 | 86.8. X P.2.J.3.12/41 | 43 | 8100 | 3.415 | 15 | 3500 | 110 | 47.1 | 91.5. P.2.J.3.13/41 | 43 | 8100 | 3.155 | 15 | 3500 | 110 | 43.6 | 99.0. With the two last ratios, the stresses are as follows:- In the Hypoids. | In the Differential gear. | In the axle driving shafts. 12/41 | 145,500 | 156,600 | 58,000 13/41 | 134,500 | 144,600 | 53,500 ✓ | ||
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).