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).
Design modifications for seat rake, petrol tank, and fuel system for American market specifications.
| Identifier | ExFiles\Box 19\4\ Scan011 | |
| Date | 13th January 1930 | |
| -4- Brewster practice allows very little rake on the seat cushions (3° to 5° I believe) so that we want a seat board either horizontal or with a very slight backward rake. (The cushions on 16 EX for example appear to us to have too much rake and tend to "jacknife" the passengers.) (2) On the sketch I have shown a similar treatment for the kick-up, lowering the seat board 1 1/2" with very slight backward rake. (3) This necessarily lowers the top of the petrol tank and at the same time we have increasingly insistent demands in the U.S. for more fuel capacity. (A 250-300 mile run is not far short of a reasonable day's touring, but 200 miles is a very short run on present highroads. I have shown a tank 12" x 18 1/2" x 32" which I do not think would lower the exhaust nozzle and would give the 30 U.S. gallons capacity which America are asking for. On the assumptions made above as to back line CC and spare wheel clearance, this tank could be got in without fouling the spare wheel position. (4) Have shown the subframe (or deep-sill) kick up brought down level with the bottom of the frame kick-up. Believe this is justified by the rear axle clearances. (5) Have shown rear rubbers 1-3/4" deep, compressed. This follows our present American mounting practice, and is proposed in view of the considerable torsional movement which seems to occur at rear of the P.II frame, to prevent the frame distortion from straining the rear coachwork construction. (6) Petrol Tank. Have shown a tank with an absolutely plain top except for a single central vent which would call for a central cut in the rear end of the 24" long roadster decks, but would otherwise be clear of coachwork. As you know we are keen on this central vented tank with sealed filler cap and low filler which will only spill simultaneously with the vent. The intention of the sketch is that this vent should contain both the petrol feed pipe (without filter) the gauge standpipes, and the new type King Seeley Sprengel pumps which pump pure air from the vent into the bottom of the standpipe. The new Sprengels are said to be so effective (ten times as effective as the old type - see Oy2.Jan.13/30) that the hand pump would scarcely be necessary. So a single gauge line would be sufficient. (Searight however points out that a single-line gauge demands a slightly longer back-leg on the instrument). With no filter in the tank we should propose a suction-type disc filter on the vacuum tank under the bonnet. We have used this combination on several cars over 10,000 miles and found this type of filter very effective and free from cont'd.{John DeLooze - Company Secretary} | ||