1. Home
  2. ⚙ Mechanical Engineering
  3. The New X-Prize

The New X-Prize

The new X-Prize is for a car that gets 100 miles-per-gallon and like the previous X-Prize is for ten million dollars.

Now there are a lot of rules but in general the car must get 100 MPG, it must reach a performance level (but not high performance), it must have four wheels, it must be possible to manufacture, and it will be compared to other entries.

I can do this but really I'm too busy at this time...and the prototype would cost about $250,000 to shop produce.

But how to do it quick and dirty ?

I thought about the Lotus Elise at 1984 pounds and 200 horsepower. Well, swap the race-prepared engine for a stock engine and re-gear the transmission. The cost would be about $55,000. The result is unknown but

1984 pounds is too heavy for 100 MPG.

Or take the car engine and transmission out of the Elise and replace it with a motorcycle engine and transmission...and re-gear the transmission. (I was hoping for a Goldwing engine with an automatic transmission but as it turns out the automatic transmission is a show vehicle only.) Now the motorcycle engine and transmission might save 300 pounds over the car engine and transmission so that puts the weight at 1684 pounds. Cost about $75,000 (with custom fabrication) and that result is unknown but it's also too heavy for 100 MPG...

Next for an entry in the hopeless category I thought of the Mazda MX-5 at

2441 pounds. Then look for fiberglass fenders, hood, and trunk lid. Also add the racing front end for lower drag and the racing rear spoiler. And there might be rocker-panel skirts for the car. Then make your own fender skirts. Oh, don't forget to re-gear the transmission and rear axle. Cost about $30,000 and no hope for 100 MPG...

Then I thought about history. The 1967 MG Midget at 1576 pounds. Of course that car comes with a small engine but not a modern engine. So replace the car engine and transmission with a motorcycle engine and transmission...and re-gear the transmission. Hopefully that puts the weight at about 1276 pounds and that starts to get interesting...if an efficient motorcycle engine has been found. (Motorcycle engines tend to have a carburetor for each cyclinder and only be concerned with high performance.) Cost about $30,000...because of custom fabrication and required parts.

But when all else fails all sports car racers know about the Lotus Super 7. The Super 7 is a 1960's Formula Junior race car that was put on the street with a wider frame, a higher suspension, and with motorcycle fenders on the front wheels. The car is a two-seat convertible with no doors but a step-in style. The car is often built with kits and almost any choice of engine. However, the Caterham 7 Classic is all ready to go. It has a 1.4 dual overhead cam engine with a four valve head and fuel injection that makes 105 horsepower. The car weighs 1155 pounds and that gets interesting. The car costs $26,000. Oh, don't forget to re-gear the transmission and rear axle as this is ordinarily a high performance car. Then if the 100 MPG result is not reached consider swapping the car engine and transmission for a motorcycle engine and transmission...

Gosh is two seats only okay with the X-Prize ?

But wow look at GM. They built a carbon fiber car with a 1.3 3-cyclinder two-stroke engine that got 100 MPG. Well in rigorous test cycles that car was said to get 60 MPG. The catch is that carbon fiber costs about $50 a pound compared to fiberglass at 50 cents a pound or compared to aluminum or steel at their prices. Of couse carbon fiber requires a special fabrication shop (like where they make spaceships) while any race car shop can make a car with an aluminum or steel frame...

Well darn maybe I will put together an entry and I'll see you there...

Reply to
PolicySpy
Loading thread data ...

Oh, I see that the X Prize has a four-seat category and a two-seat category. And 5 cubic feet of cargo space is mentioned.

But really the four-seat category would be most significant because we don't want high MPG associated only with small cars...

Reply to
PolicySpy

If you want to do it to actually build something, that has any real meaning, you'd want something that has performance, passenger space, and cargo space similar to a Toyota Camry. Bonus points if you can achieve that with a mini van.

Reply to
Mike H

First off, I think the Elise is a very poor start.

Race cars have body shapes that are specifically designed for down force, which is required at high speeds. If you check the coefficient of drag, you will find that they are almost like a flying brick.

To attain 100 mpg, it must look much more like an airplane.

The most aerodynamic automotive shape produced was the GM EV1 at .197

formatting link
formatting link
for a Learjet 24 = .022

formatting link
for a Formula 1 = .7 to 1.1 Hummer H2 = .57 Prius (2004) = .26

Total drag is Cd x frontal area.

Reply to
Mechanical Magic

I'm simply looking for light weight and then an engine size relative to the weight. The Elise at 1984 pounds is too heavy for 100 MPG but has a very strong frame for its weight...

Sedans or sports cars based seldom have net downforce but a reduction in lift is often a reduction in drag...

But we avoid tandam seating and then just favor low height...

Frontal area is just as important as shape...but of course that favors small cars.

But sure mention aerodynamics. In fact look at the MX-5 project in the hopeless category. And add the racing suspension to get the car lower.

And air blocked from getting under the car either by crude spoiler shape or by sophisticated spoiler shape...is a large reduction in lift and drag. In fact a large front spoiler is so effective that there will never be a rear spoiler large enough to reduce the lift at the rear by the same amount...and thus the famous rear wing. Or just skirt the car all the way around, let the skirts drag on the ground (because moveable aerodynamic devices are banned by international agreement), and keep the car low to the ground.

Reply to
PolicySpy

My thoughts turn immediately to the Ford Festiva: 1.4 fuel injected engine, four seats, bags of cargo room through the back gate, and as sold, 43 mpg on a steel unit body. They went with a 100 kmile drive train warranty. My wife's lasted a quarter million miles. Did I say 43 mpg in standard trim? Glass doors, lid and body panels, and you're up to 60 mpg no sweat, I'd say....

Brian W

Reply to
Brian Whatcott

Yeah, find a 1.4 engine with 4-valve head and fuel injection. But put it in a 1000 pound car...

That's not really difficult. Make a tube frame of either steel or aluminum and then cover the frame outside and inside with something like Royalex. (Canoes use Royalex as primary structure but here we just use it as unstressed bodywork.)

And Rover has a 1.4 engine...

Now Honda Motorcycles has a 754cc liquid cooled twin with 3-valve head or a

583cc liquid cooled twin with 3-valve head. Then there is a lot of carburetor technology for motocycle engines so that smaller carburetors may be possible.

Of course Ducati has a 1078 liquid cooled twin with fuel injection...

---------------------------------------------------

But one of the other posts mentioned aerodynamic drag. But see that's funny because there will always be a goofy entry with tandem seating, airplane fuselage shape, with no concern for air flow under the vehicle, and no concern with cornering ability.

A car must have width and can only be low to make up for the width. But also prevent airflow from going under the car and aerodynamic drag is drastically reduced.

--------------------------------------------------

Reply to
PolicySpy

Uh, how about 3145 MPG?

formatting link
I don't know, but talking about 100 MPG when a year or 2 ago somebody got

3145 MPG? Please, don't get nutty about that it wasn't designed to get the X-Prize. Point is certainly a usable and practical version that gets a measly 1/10 th mileage of 314 MPG must be possible!
Reply to
Tony

They claim around 200 MPG:

formatting link

Reply to
Jake

Perhaps for the World market, but for the American Market, the Toyota Camry is pretty much the typical family car. That would be a true winner. A Ford Festiva, would not IMNSHO.

Reply to
Mike H

That's alot of bucks! I've been thinking about high efficiency cars for a long time, although I'm not an inventor - I think I have a few good ideas.

I'll have to check out the rules. Hey if I give you an idea you can work with, then you can share part of the prize. Heck, 2.5 million would work :)

GOAL: Get the car to go further with a given amount of fossill fuel.

SOLUTION: Increase the effeciency of said car's use of fossill fuel.

(a) The lifecycle of a car ride. (a.1) Off (a.2) Starting. (a.3) Started. (a.4) N number of state transitions: (a.4.1) (Speed =3D 0) --> Acceleration (a.4.2) Acceleration --> (Speed > 0) [i.e. the light turns green] (a.4.3) Acceleration --> (delta Speed) [i.e. press on gas or brakes] (a.4.4) Acceleration --> (no change in Speed) [i.e. Changing Langes] (a.4.5) Acceleration --> (Speed =3D 0) [i.e. Slowing to a stop] (a.5) Turning Off (a.6) Off

Are you with me this far? If so, I'll elaborate.

Do I sound like a lunatic? This is Aaron Anoddie - I've been posting here on and off for years under various logins. I'm not a trained Physicist, but I can think abstractly and sometimes have valid things to say.

Regards, Aaron

Reply to
Aaron Anodide

..

Ha! When my wife's Festiva recently dumped transmission oil and demolished its transmission after a quarter million miles, she bought a used Camry - and she's been oohing and ahing about it since then.

But a Camry doesn't come with a 43 mpg tag either....

Brian W

Reply to
Brian Whatcott

Mechanical Magic wrote in news:3bd2c346- snipped-for-privacy@s19g2000prg.googlegroups.com:

Not for aeroplanes it isn't. The reference area is (from memory) the wing planform area.

So your comparison is out by a factor of 5 or more.

Your claimed CdA for the Learjet fails the reasonableness test since it implies laminar flow over the entire shape, which is not possible.

Cheers

Greg Locock

Reply to
Greg Locock

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.