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).
Weight comparison for 20/25 HP Gear Box Castings made from Magnesium and Aluminium.
| Identifier | ExFiles\Box 107\4\ scan0130 | |
| Date | 3rd August 1934 | |
| 4538 3.8.34. Weight of 20/25 HP. Gear Box Castings in Magnesium. Magnesium. Aluminium Gearbox (bare) 11 lbs. 15 ozs. 18 lbs. 1 oz. Diaphragm. 3 lbs. 1 oz. 4 lbs. 9 ozs. Clutch Casing. 7 lbs. 0 oz. 10 lbs.10 ozs. Clutch Insp. Cover. 3¼ozs. 4 ozs. Top Rear Cover. 6 ozs. 9 ozs. Top Front Cover. 4 ozs. 6 ozs. TOTAL ...... 22 lbs. 13¼ozs. 34 lbs. 7 ozs. | ||