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).
Comparison of specifications for Saloon and Limousine Goshawk-11 model car roofs.
| Identifier | ExFiles\Box 107\4\ scan0039 | |
| Date | 12th June 1923 guessed | |
| DETAILS OF BODY CAR ROOFS. DETAILS. (Saloon) 7-Goshawk-11. (Limousine) 3-Goshawk-11. Average height above frame of roof between windscreen and front and rear step iron. 4 ft. 5 15/16" 4 ft. 5½" Width at rear of front seats. 4 ft. 6½" 4 ft. 3⅞" Area of roofing. 4880 sq.in. approx. 5377 sq.in. approx. Thickness of roof. 5/16" approx. ⅜" approx. Weight of roofs (Wt. of 1 cu.in. of material taken as .02" lbs.) 30½ lbs. approx. 40 lbs. approx. Details of roof stiffening. Wt. 1 cu.in. oak .027 lbs. " " " " steel .27 lbs. Steel 55.5 cu.ins. = 14.9 lbs. Oak 1017.75 cu.ins. = 27.48 lbs. Steel (?- Oak 938 cu.ins. = 25.3 lbs. Details of top framework of body (1 cu.in. taken as .027 lbs.) 1270 cu.ins. = 34.3 lbs. 1270 cu.ins. = 32.7 lbs. TOP OF FRAMEWORK AS TAKEN Total wt. of roof without steel stiffening. 92.3 lbs. approx. 98 lbs. approx. Wt. of steel angle iron. 14.9 lbs. (?) Wt. of aluminium drip moulding (.18 lbs. per ft.) 3 lbs. ------ Total weight of roof. 110.2 lbs. 98 lbs. | ||