From: JayBaldwin@aol.com [mailto:JayBaldwin@aol.com]
Sent: Tuesday, August 02, 2005 8:38 AM
Subject: Dymaxion car
Hi. The first car actually weighed 1600 lbs, not 1000, and the second car and third car were much heavier. It is interesting to note that Amory Lovins' proposed fuel cell Hypercar is specified at about that weight—the least that can be considered safe in a crash. The first car rolled while racing a Chicago politician's car which bumped it, fatally injuring the driver when the canvas roof caved in on him, (see my extensive article, right from the Fuller Archives, in Automobile magazine, July 88). When Bucky rolled his own car, (I think it was car 3 after symphony conductor Leopold Stokowski's wife, for whom it was built, tired of it) he took a corner too fast and went up an embankment, then rolled back down sideways. In neither case was the car at fault, though the driver had to get used to it steering from the rear like a forklift. The car was a real handful in a side wind, not because of the steering wobble (which were gyroscopic effects that also affect motorcycles) , but because, generally speaking, the more streamlined a car is, the less stable it tends to be in a side wind unless suppressed by very clever detailing. It really needed a large vertical stabilizer such as the one on Jan Andreau's 1936 Peugeot (see the book, Streamline). The Dymaxion car was intended to fly; sidewinds to not affect the stability of air craft as they fly. But a car must stay on the road. That's a different matter. At the time the cars were built, very little was known about stability , especially at high speeds. The Dymaxion rarely got 30 miles per galloon, and never higher. It was, however much better than the Ford with the same early V8 flathead engine.
There is no point in replicating any of the three Dymaxikon cars, they are very obsolete in every way. Bucky's later car designs, done for Henry Kaiser, still had 3 wheels, but were 4-seaters with an engine and steering in each wheel. No prototypes were built, and kaiser rejected the design. Suspension was to be hydraulic as is found in Citroen cars (Bucky owned a Citroen. I have had four of them). Personally, i do not like 3 wheel cars whether the single wheel is front or back. In front, it make the car hysterically unstable duiring heavy braking and emergency cornering. At the rear, whether steered or not, a single wheel makes it impossible to have rear cargo loading. This makes the vehicle less useful. Rear wheel steering at low speeds has its charm, but the movies of the Dymaxion parking in its own length are misleading: the car goes into the space just fine, b ut must back out into traffic to get out again, unless it parks far from the curb (to give the tail room to swing) or there is a lot of room ahead. On short, the cars were not completely worked-out, and Fuller himself dropped the idea of a car that big, and car that could fly, held up by "jet stilts". It is my opinion that he was right at the time, and still is: since the first Dymaxions were built, there are ten times more cars on the road, and though jet stilts are possible technically, they would be way too noisey and fuel-hungry. Good try, though. Bucky's small cars are more interesting for today's uses, and might be worth attempting. On the other hand, congestion has become the main problem of automobility, and even Lovin' proposed Hypercars will not help that. The cars ehtmeselves are only a part of the Big Picture of personal transport. The best solutions will come from looking at the matter from a comprehensive standpoint, as Bucky taught. JB
From: JayBaldwin@aol.com [mailto:JayBaldwin@aol.com]
Sent: Sunday, August 14, 2005 11:22 AM
Subject: Dymaxion chassis
Hi Ben. More on modeling the Dymaxion car: The patent drawings and most photos of the Dymaxion cars do not make clear the layout of the chassis. The chassis of the unbodied first attempt was unsatisfactory, as i note in BuckyWorks. It allowed the rear wheel to lean with the body, giving very undesirable gyroscopic effects. The first bodied car (Car#1) had an enormous chassis beam running down each side connecting the rear wheel to the front axle, keeping all three wheels vertical at all times. The big beams resulted in an annoying climb into the rear seats, and made too much unsprung weight. Car #2 (which still exists in Harrah's collection,as you know) utilizes three separate, sprung chassis. The first part is attached solidly to each side of the solid front axle (it is actually the rear axle of a 33 Ford sedan), and carries the engine at its rear end, where the engine's mass can
counteract the motions of the second part of the chassis, the rear wheel's A-frame. That A frame is much shorter than car #1's enormous beams, effectively allowing a reasonable climb into the rear seats, which can also be wider. The A frame greatly reduced the unsprung weight at the rear, giving car #2 a much better ride and roadholding compared to car#1, yet, because it was hinged to the first part of the chassis, it still kept all three wheels vertical at all times, regardless of body lean. It was sprung by a transverse leaf spring in tension, from which the tail end of the first part of the chassis was hung. The third part of the chassis carried the body. It was carried on two very long leaf springs that rode upon either side of the front axle. According to Bucky, Car#2 and #3 (which had a similar chassis, but was much heavier) rode so well that he could drive across railroad tracks in the freight yard, and navigate plowed fields without jiggling the passengers.
Note that his later designs put the engines in or near the wheels, which were independently sprung by what amounts to the air/hydraulic units still found in the better Citroen cars. This was much lighter, simpler, and doubtless would have been cheaper. Today, he probably would have specified fuel cells and an electric motor in each wheel, with computer-controlled three-wheel steering only at low speeds. When I met Fuller in 1952 (I was 18), I had a big argument with him about that single real wheel, contending that it would prove lethal if the tire blew out. He agreed, noting the he had specified dual tires there on later versions for just that reason. In any case, i expect that it would be very difficult to produce a useful computer analysis of the chassis perfomance of the Dymaxion cars unless you could accurate estimate the weight all significant parts, and its distribution, center of gravity loaded and unloaded, center of wind pressure, spring rates, roll centers, shock absorber action, steering geometry and various wind tunnel readings.
By the way, the Fuller Archive does have interior shots, but all i saw were of car #1, and showed just one rear bench seat for two or three (crowded) passengers. Hope this helps. JB