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).
Performance characteristics of springing, vibrations, and steering for the 'Goshawk' model.
| Identifier | ExFiles\Box 49\3\ Scan011 | |
| Date | 12th January 1921 | |
| Contd. X.3524 / 26 -4- X.3481 Extract R4/G12.1.21. (10) SPRINGING X.3527. X.4262. You must expect bad springing with twoo stiff spring, except at high speed, but even, then they would want severe damping. When you mention4" do you mean or - 2" or and - 4". You would not expect any good from the former but the latter would be fair. We generally try for a spring deflection of 5" or 6" with 4" clear to the buffers. If you get this, then you will have to rely on shock dampers to perfect ( as far as possible) the riding, but you will never get big heavy cars' behaviour, though we should expect it to be better than any of the same weight and wheelbase, or we must make it so "Goshawk ll" is a little longer in the wheelbase and the springs being semi-elliptic will have more friction than the cantilever, and therefore will not need so much damping, but naturally perhaps cannot be made quite so nice with ideal dampers. The length of the springshas no effect on this point, only that long springs have less friction and are generally fitted up softer with more clearance between axle and frame. (11) WEIGHT. Wonderfully near what we worked for, which was about half 40/50 H.P. (13) VIBRATIONS. X.3493. As mentioned earlier, bad back axle gears would cause this intermittent drive, coinciding with the natural period of torsional vibration of the bevel gear system in the centre of the back axle, a similar vibration on 40/50 H.P. with straight gears, but not with spiral bevels or worm drives. (14) STEERING X.3516. Steering should be good, if you can give more lean without wobble do so, and introduce enough friction just to damp slightly by fitting plain washers on one or both stub axle thrusts. I have heard from Mr. Haldenby that steering wheel was too fat to hold nicely, especially with glovers. Get another in hand, but try to improve the general design - see memo to Da.{Bernard Day - Chassis Design} I have not mentioned the points you are pleased with, and feel sure we shall all like this size of model, and hope "Goshawk 2nd" will be as good, and by getting this nearly right, will save time on "Goshawk 1st." I would liek to see the chassis as | ||