high body or low? wanting to build a car from scratch

[theycallmeebryan]

I'd build a Tandem reverse tadpole vehicle.... like the HyperRocket.



However, instead of a 250cc parallel twin Ninja 250 motor, mine would have a 100-150cc fuel injected single cylinder 4 stroke engine with a small turbocharger and a 5-6 speed transmission. I'd also make fairings for the front wheels.

Also you could extend the chassis a bit as to accommodate 2 passengers (3 total seats), or more.

[sjr]

Originally Posted by darcane

Your only goal is efficiency?

Go low.

Cars are built high for practical reasons. Comfort, visibilty, safety.

Land speed racing has many ties to fuel efficiency. The better streamlined your car is, the less power you need to go a certain speed. In land speed racing, this translates to higher speeds with less power. For fuel efficiency, this means less fuel at the speed you drive.

One of the most innovative cars in racing is a series of cars called the Nebulous Theorem. They are built with nearly no ground clearance and extremely minimal frontal area. The NebII has set records at 360mph with a turbo 1.5L engine. (About 700hp). Power needed to overcome aero drag cubed is proportional to speed. So, if you assume 700hp to overcome drag at 360mph, only 3hp is needed at 60mph.

Pics can be found here:
Worlds Fastest 4 Cylinder Nebulous Theorem II

ok thats cool I wont need to go over 70 mph, mostly 50 and under




so Im hearing different choices from you guys, some high some low , i can go either, so whats the pros and cons of each? I see both on the net, remember Im only going 50 mph 15 miles round trip to work

[jamesqf]

First thing to consider is where you're going to be driving. What are the roads like? From an overall efficiency standpoint, improved aero doesn't help much if you frequently scrape the belly pan on the pavement. (Don't laugh: I was seriously worried about getting the Insight high-centered on stretches of I-80 over the Sierra, where heavy truck traffic &c had worn ruts into the concrete.)

That's one of the reasons I like an Aptera-like design, with a smooth belly well clear of the road.

[jamesqf]

Originally Posted by sjr

...remember Im only going 50 mph 15 miles round trip to work

Only 15 miles RT? Forget the car and get a bike. If you want to be super-efficient, get a recumbent with fairing. Then you can add electric assist...

[sjr]

Originally Posted by jamesqf

Only 15 miles RT? Forget the car and get a bike. If you want to be super-efficient, get a recumbent with fairing. Then you can add electric assist...

no.... I like a enclosed heated box, and a bike wouldnt compete with the trucks and cars on the road, I need to go the speed limit

[some_other_dave]

Low also gives you visibility issues. Both having a hard time seeing around traffic and roadside obstacles, and the latte-chugging soccer mom who can't see you while she is on the phone while applying make-up in her lifted Expedition...

Low also gives less weight transfer under acceleration, braking, and cornering. In general, that will make for better handling.

-soD