Dymaxion Deathtrap

[Big Dave]

Good aero. Terrible car.

A Harrowing Test Drive of Buckminster Fuller's 1933 Dymaxion Car: Art That's Scary to Ride | Open Culture

A car that steers like a fork truck. No wonder it never caught on. One wonders if a better chassis under that sleek shape wouldn’t have helped.

[Otto]

Aptly, this video describes this as like driving a taildragger plane down the road. That's because rear steering is inherently unstable. Makes for a small turning radius, though.

Put the steering in front and she's stable: A teaching aid used in aeronautical engineering classes is a tricycle with fixed wheels on two corners and a castering wheel on the third. Roll it down an incline with the castering wheel in front, and she rolls straight and stable. Turn it around and roll it with the castering wheel at rear, she darts off to the side and ground loops.

That's why steered nose wheel tricycle landing gear is on the vast majority of modern aircraft, despite the extra weight of the nose wheel.

Buckminster Fuller was brilliant, but his car would have been vastly better had he at least had the front wheels steering, as is done on some modern motorcycle tricycles.

[whatmaycome14]

Yeah... I think if it were FRONT steer, it would probably be a lot better. This makes me think of how (easy or difficult) it would be to convert a FF car to a 3 wheeler... slap on an aero body and call it a day.

[freebeard]

What a happy day for me. <<does a little dance in chair>>

This is an excellent video for a number of reasons. For one, this is not Sir Norman Foster's replica of Dymaxion #3. This is the Ur-Dymaxion replicated. I love the canvas top and off-the-shelf spotlight tuned periscope.

On to the handling: Bucky wasn't building a car. He was building a test vehicle to test the ground handling characteristics of his real goal—the Omni-Directional Transport—which was to be VTOL. That's why it handles like a tail-dragger. There was also a complete redesign of the chassis in #2 and #3. [From memory] the '3-hinge' and '2-hinge' designs.

Here's a pre-#1 design:

I think ultimately 3-wheel drive and 3-wheel steering would be optimal, but differential braking in front might be sufficient. Especially when the plan is to fly the rear wheel preparatory to takeoff.

In short, the vehicle, and the fact that it exists, is excellent. He should park it in a chopped Butler grain elevator!

[gone-ot]

This picture better illustrates the Dymaxian's original "aircraft" intentions:




"back-of-the-napkin" sketches:

[freebeard]

Also the Isamu Noguchi model:

http://greg.org/archive/2008/12/07/fuller_x_noguchi_colabo_dymaxion_car_model.html

...of which; according to the link it sold for $92,500 at Southby's in 2008!

The [Mechanix Illustrated?] cut-away shows the 'air keel' which disappeared in the real-world Dymaxions. Also missing triangulation in the frame above the front shock mounts. I suspect these pictures were by a magazine staff artist from descriptions.

The first unbuilt Dymaxion (#4) was to be a 6-tired tricycle with inhub motors. And an extensible tailboom for a variable wheelbase.

________

Edit: There's a lot of news at

http://blog.hemmings.com/index.php/t...inster-fuller/

Build details of the new replica, #2 has been restored, and original blueprint drawings were found in a random house attic.

[Big Dave]

I think there is scope for making Bucky's overall idea work. It just needs a little common sense engineering.

One approach might be to use the chassis of one of the Bombardier "tadpole" motorcycles. They are front-steering and a single rear drive wheel. That might be the perfect chassis for a 'Dymaxion' tandem-seat car.

[elhigh]

The thing about that taildragger designs is that as the tail swings out of line, forces tend to pull it even farther so that it is dynamically unstable.

If the steering knuckle were behind the wheel instead of in front, it would tend to pull itself back into line. Tend, I say, but I also think that it would be subject to a nasty case of the wiggles at virtually any speed. It would need a mighty steering stabilizer and tight bushings to keep things civil.

[JRMichler]

All too true. I had a ride in the back seat of an Aeronca Champ once where the pilot went outside the runway lights twice on one side, and once on the other side of the runway. By pure luck, he did not hit anything or ground loop it.

[freebeard]

Bucky knew that the ground handling characteristics of his Omni-Directional Transport was going to be the hardest part, while he was waiting for Harrier jump-jet-style takeoffs, without the Citroen or Cord FWD parts he needed. He said it always takes 3 pre-production prototypes to get it right. And everyone wanted to go to production at two. That's why he walked away from the Dymaxion House.

I've heard that tandem axle trucks do less slipping and sliding in mud, so maybe having two inline, no-steering wheels in back would be more stable. Like this: