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).
Rear axle temperatures, worm drives, Girling brakes, frame construction, welding methods, and standard saloon body assembly.
| Identifier | ExFiles\Box 154\2\ scan0045 | |
| Date | 12th October 1937 guessed | |
| -3- This has reduced their maximum rear axle temperature from an impossible figure, since no previous axle has stood up to continuous "flat-out" driving at Brooklands ( in which conditions temperatures of approx. 440°F have been attained) to a maximum of 160° - 170°F.{Mr Friese} In similar conditions, a car having been run round Brooklands continuously for one day at an average speed of 73 m.p.h. The worm wheel pitch diameter for this car is 4.75", and the worm threads are the involute helicoid type described by Dr.Tuplin in an article in the Automobile Engineer for August of this year, this tooth form enabling grinding of the worm to be carried out with a straight sided grinding wheel. In their experience the worm and wheel are more expensive to produce than spiral bevels, but are easier to make and keep quiet in production. The worm drive implies a longer propeller shaft, owing to the worm being below the axle and the pinion in front. They have had no trouble with Girling brakes, except that if there is too great an accumulation of brake lining dust they may grab. [handwritten note above: '[crossed out] Let's have a picture of this' 'let's have one'] [text 'they may grab' is crossed out] [handwritten note in left margin: 'L.E.S. we should talk to Rubery Owen as soon as paper prices are completed'] The frame is obtained from Rubery Owen, and comes in as a complete unit. The weight is 243 lbs, the price £5-16-0d. and the tool cost £5000 approx. It is stiffer and lighter than their Light Straight 8 frame. The front crossmember ( pan ) and frame are 0.128" thick, and the gusset and cross .104 thick. They find welding more reliable than rivetting, saying that all rivets must be tested by tapping, and any that sound doubtful must be drilled out and replaced. Arc welding is normally employed, the distortion from oxy-acetylene being more, and the torque arms of the front suspension have their seams welded by an arc struck from a carbon electrode. H.P.S. [handwritten note: 'How are we situated for Arc welding'] The standard saloon body is principally steel, with however still some wooden parts; they buy two separate units, one the scuttle and screen, and the other the tail, from two different outside firms, and these are assembled into the finished body by themselves, steel cantrails and door pillars being welded in, and the sill being partly steel and partly wood. Their die cost for the two sub-assemblies has been in the neighbourhood of £50,000 to £60,000. | ||