Parallel Hybrids

[freebeard]

Urbee and Edison2 both rely on reduced parts count for manufacturing efficiency. The Urbee seems to have lost 100lb, between the Wired article and the Gas2 one that references it (1200-->1100lb). The VLC, at 1400lb, carries 4 passengers and the windshield isn't horizontal.

RBFuller put 250,000 miles on a rear steering car. Of course, he wanted to lift the rear wheel off the ground aerodynamically and steer with the two front wheels, too.

[cRiPpLe_rOoStEr]

Rear-wheel steering doesn't seem so safe at all. I'd rather get all-wheel steering instead...

[niky]

Having the rear wheel lift off at speed, having the fronts do all the motivating, steering and weight-carrying... that would be darn fantastic.

[freebeard]

[Recumpence]

I have a large amount of experience with light weight tadpoles running 50 to 60 mph. They are very stable assuming the cg is correct. They also love to be powered out of corners hard. I have youtube videos of me driving single seater pedal electric tadpoles with 40 horsepower (100 pound weight) and pushing them VERY hard without any problems.

Rear steering is just plain stupid, though.........

Matt

[GreenHornet]

3 wheeled vehicles have been around for a long long time and will continue to be for the simple fact they cut size, weight, and costs. For a small commuter vehicle that does not need to drive over 100mph they can be a very attractive option. They can be designed in many different ways which is why they often get misjudged as dangerous or easy to flip. The delta design is the one that most people know and remember because this is the one in which most people have memories of flipping. The 2F1R or tadpole configuration on the other hand can be built much more stable than the delta version and similar or in some respects better than a modern 4 wheeled car.

Not only does the tadpole version cut size, weight, and costs it also increases vehicle efficiency in many ways. One of the more noticeable ways it increases efficiency is with the term (PMOI) Polar Moment of Inertia. A 3 wheeled vehicle has dramatically reduced PMOI which creates a more sport car handling feel. It also takes less horsepower or energy watts to get it moving due to the decreased weight of rotational mass inherent in the 3 wheeled design.

If your goal is to build or design a highly efficient electric car than an ideal candidate is a single powered rear wheel! One that is fixed and does not steer that is keep the steering up front I concur with others its safer and far less complex.

However despite my personal opinions I am enjoying reading about the Urbee and the work being down by them on the single rear wheel steering. I think they are doing a fine job thus far taking on a difficult engineering design approach. It would be a dream to park it I bet!

[freebeard]

That's an interesting point about Polar Moment of Inertia. A tadpole also leverages whatever Torsional Rigidity the chassis possesses. But the single drive wheel instead of three (in-hub electric)?

If I had an off-road vehicle, instead of a pickemup, I'd want it to be a VW Beetle with the [rear window] engine and rear lid removed and a 6' tall chain-mail torus tire over a tractor inner tube slotted in there. Hubless—if it was jacked up a bit the bumper could run through the hole.

[GreenHornet]

That would be a pretty sweet setup for sure freebeard I always liked the VW beetle and gias for there simplicity and adaptability. I think the ultimate and one of my favorite cars of all time is the Type 60 K 10 and Porsche Type 64 models. They were the predecessors to the bug and were extremely simple and elegant in there aerodynamics. Not sure what there coefficient of drags were but looking at them they appear to be well streamlined.

[freebeard]

Heh, I was thinking about that just today.

How about the same thnking in a 4-passenger body? Behold the Volhart Saggita

maybe with a retro-styling update like the Audi Rosenmeyer Concept

[NeilBlanchard]

The VW XL1 is nearly a pure parallel hybrid - which is very strong case in point. Please note the need for a 7 speed dual clutch transmission. But, the results speak for themselves.