Automotive X-Prize: "The Very Light Car" (also very aero) with conventional engine

[dcb]

Originally Posted by cfg83

Did someone save some pictures of that trike?

There are a few at the bottom of Bens blog

HyperRocket: 125 mpg, 100+ mph 3-wheel motorcycle | Hypermiling, Fuel Economy, and EcoModding News - EcoModder.com

[NeilBlanchard]

I'm having more questions about this "Very Light Car":

What is the transmission? With a (very) small displacement ICE, you'll need a pretty sophisticated many-geared transmission. They show a clutch pedal...

The side intake(s) are for engine cooling, and I think the rear (oval) vents are for the heated air to exhaust out (I think?). Are there any provisions for cabin ventilation? (Obviously, there is no A/C.)

The front suspension remains a mystery -- maybe it is torsion bars inside the support tube struts? Is the steering rod also inside there, or is it behind it?

Does this car have a version of Stop/Start?

How much does it weigh?

[dcb]

Originally Posted by NeilBlanchard

Does this car have a version of Stop/Start?

Lol, you mean like an ignition switch with predictive logic attached?

Originally Posted by NeilBlanchard

How much does it weigh?

dunno, they said the rotors were 1/5th the weight of standard rotors if that is a clue.

[cfg83]

Cd -

Originally Posted by Cd

Well, I'm a poor man.

How much is the cost ? I didn't see it on their site.

They're being very cadgy on their website. I don't see this as a production car in any way. It's a design exercise intended to show examples of weight savings that could be integrated into conventional automotive car design. I think they are trying to get their message "into the ether" via the media attention of the X-Prize. Nothing wrong with that.

I bet they are hoping to patent the transfer case :

The rear transfer case acts as part of the driveline and the rear swing arm suspension

I *could* imagine them selling plans and/or kits to the public.

CarloSW2

[dcb]

I wonder if it is single wheel drive? Should be more efficient and not need a diff.

[Bicycle Bob]

It looks as if the wheel fairings were designed without reference to the airflow pattern around the main body. It isn't easy to get suspension plus accurate wheel control in the space shown, especially at a reasonable weight. I don't see any gaps or other clearances to allow bounce or even steering, so we may be looking at a crude mock-up. They do refer to swing axles, though, not trailing arms, so perhaps it will have the handling of the old VW bug. I'd also expect stressed body panels in a lightweight, not a tube frame with only a vague attempt at triangulation.

[Frank Lee]

Bob: look at the pics, see how the wheel centerlines are behind the axle tubes. Trailing arms.

[Bicycle Bob]

I wonder what they think "swing axle" means. I'm content to wait for wait for detailis with the news, if they make some.

[RobertSmalls]

I love this car, though its very good aero is more important to its success than its light weight. I'm sure a production version would use cheaper materials, resulting in a heavier car, forcing a larger engine.

One great thing about weight reduction, is that it allows more weight reduction. A smaller, lighter engine can motivate a lighter car, a lighter frame provides the same stiffness as a heavier frame on a heavier car, a smaller gas tank provides the same range, etc.

I would love to see these six gram lug nuts.

Having read about those >1lb brakes (rotors, presumably), I couldn't resist running a calculation. Assume your brakes need to be able to do a panic stop from top speed on a warm day without boiling your brake fluid. Assume that the top speed of the Very Light Car is 75mph, and that its braking system has a thermal mass of 2kg and the same specific heat as cast iron. Thus the mass of the vehicle, its occupants, and its cargo is not more than 315lb.

Uh huh.

Maybe they have aluminium brake rotors with cast iron linings, and a 630lb car?

[cfg83]

RobertSmalls -

Originally Posted by RobertSmalls

...

Having read about those >1lb brakes (rotors, presumably), I couldn't resist running a calculation. Assume your brakes need to be able to do a panic stop from top speed on a warm day without boiling your brake fluid. Assume that the top speed of the Very Light Car is 75mph, and that its braking system has a thermal mass of 2kg and the same specific heat as cast iron. Thus the mass of the vehicle, its occupants, and its cargo is not more than 315lb.

Uh huh.

Maybe they have aluminium brake rotors with cast iron linings, and a 630lb car?

Thanks for doing this calc. 315 lbs sounds fantastical without using exotic materials like carbon fiber, which they don't want to do. When I was looking at the test mule, I was thinking kit-car tubular chassis. It looks like a dune-buggy.

They claim their brake rotors are 1/5 the weight of a regular car. My car weighs 2400 lbs. From my simplistic POV, 2400 / 5 = 480 lbs. Their mule only has one person driving it, so I will assume only one passenger. The average weight of an American Male is 191 lbs. That's 671 lbs.

Does that look similar to your numbers?

CarloSW2