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).
Vehicle handling, impact resistance, and the crash safety benefits of a chassisless design.
| Identifier | ExFiles\Box 117\1\ scan0087 | |
| Date | 31th May 1936 guessed | |
| 5. swerving or extreme turn, it is essential to have an easy handling unit, with a maximum of road stability. 2. Probably next in importance is the ability, in the unavoidable crash, to cushion the impact for the occupants. This also includes resistance to crushing and breakage. There are so many different things that affect the balance, or handling of the vehicle that I will not attempt to outline them but merely touch on the points improved by the chassisless design. The simplest way to improve the handling of a vehicle is to lower the center of gravity. Here again the difference between a large main frame and the surface stressed body allows the center of gravity to be lowered inches. Impact resistance is dependent on the local deflection of the body members. When two quite rigid members collide, the net result is a violent rebound of both of them, the distance being inversely proportional to their respective weights. There is a certain amount of Kinetic Energy stored in each which must be dissipated according to physical laws. It is desirable to make the vehicle shock absorbing to the greatest possible extent. Borrowing the corner pool table for a moment, remember the impact velocity of the cue ball when striking another ball head on. The rebound is most violent and sufficient to cause considerable commotion on the pool table. Now, suppose we substitute a sponge rubber ball for the ball to be hit by the cue ball. Striking this sponge rubber ball with the same velocity as before, the re-action is not nearly as violent, nor the commotion anywhere near that obtained previously. To return to our chassisless vehicle, we have a comparatively thin, semi-resilient shell which does just this shock absorbing job exemplified by the sponge rubber ball. In our motor coach design the body sheet is fastened on over a network or ribbing of "T" sections spaced about 32 inches apart and running transverse from the lower body line over the top center and down to the opposite side on the bottom. The entire bottom is tied around with another light member which encircles it, including over the wheel-housings. At the moment of impact, localized at some point on the vehicle, the light structural members yield to the blow and gradually increase the loading through the exterior sheet and short tie members interconnecting the "Tees" and "angles". This increase of loading on these members absorbs a great proportion of the impact blow, so that the relative rebound movement of the whole vehicle is reduced considerably. This sheath or skin held rigidly around the body sides has a definite protective effect for the vital parts, such as engine, transmission, etc. The likelihood of damaging a unit is lessened by the cushioned impact, and the further chance that the whole unit will not be knocked out of alignment. Unless the damage is extremely severe, the crushing is localized to a great extent and thus protects the major units. In the conventional design a shock load on either of the frame horns front or rear will misalign the whole unit, and any unit mounted comparatively rigid thereto is either broken or distorted so as to render it useless until repaired or rebuilt. With future design trends towards the center or rear engine design, this problem of vital unit protection is even more | ||