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).
Page discussing the evolution of vehicle design from 1927, focusing on the transition from traditional frames to chassisless construction for better weight distribution and structural integrity.
| Identifier | ExFiles\Box 117\1\ scan0084 | |
| Date | 31th May 1936 guessed | |
| 2. or the most efficient distribution of metallic substances. Of course, we all know that horse and buggy habits of thinking were quick to leave their imprints on early automotive construction and I often wonder now why there was not more blending into this early industry of the secrets the boat and bridge builders had to learn, ages before the automotive vehicle was ever thought about. Looking backward now, one wonders why we never could see the idea of putting one of those perfect old truss bridge types on wheels as a vehicle for carrying human beings. Getting back to our own personal experiments in 1927, we had arrived at a place where previous construction convinced us that a mass of metal, that part known as the frame, was incapable of controlling the movement set up in the structure, even on paved roads, regardless of its kind or amount. Therefore, we must find some way to spread our metallic content, or, in other words, achieve entirely different distribution of metal. We were looking for more box-like breadth and depth. In this way, we were soon to realize that even less metal than we had been using could carry a much heavier load. Best of all, we glimpsed, for the first time, what to us was a startling discovery, namely: that our vehicle chassis and body were fighting each other, rather than complementing and supporting each other. We, in 1927, began to consider a new location for the power plant, and, having a realization of the weight saving that we were going to effect with the chassisless design, were encouraged to consider two smaller power plants mounted amidship and driving directly by shaft to each rear wheel. This was for the purpose of allowing ourselves an additional opportunity to reduce weight. Today, with further experience, we are using only single motors, used in the rear and housed in an insulated space entirely separate from the passenger compartment. When one witnesses the slow motion pictures of an athletic event or thorobred horses, whether or not he is of an engineering mind, he is greatly impressed with the importance of balance and distribution of weight, as Mother Nature planned it in humans and animals. Keeping this striving for balance in mind, permit me to describe, in brief way, what has been in our mind in building our chassisless type of motor coach. In particular let me outline how we have discovered that, in this type of construction, we have an even greater factor of safety due to the balance and distribution of weight, which causes end blow or impact to have its force spread over the widest possible area. Returning to the elimination of the main frame member as a load support, the old story of the bridge truss fits the picture here perfectly. An automotive vehicle to be acceptable cannot have appreciable deflection, either in a trans-verse or longitudinal direction. There are two major alternatives to this vital problem of design: either make an extremely rigid, heavy main frame or beam, or increase the depth of section tremendously around the neutral axis. In our early experiments, with long wheelbase vehicles, it became more difficult to maintain rigidity of the frame channels, particularly in the longitudinal direction. The direct result was, as I intimated before, that the con-stant compressive and tensile stresses wracked and severed the bodies at points of maximum deflection, and no end of reinforcing eliminated this condition. As a direct comparison the | ||