Electric Vehicle C

[Paradox21]

Would it be legal to have the front of a vehicle have 2 wheels and have the back be a ball bearing?

[fleet130]

Would it be legal to have the front of a vehicle have 2 wheels and have the back be a ball bearing?

You can do pretty much anything unless it violates the rules. What rule do you think this might violate? I don't see a problem with it. It would be a 3-wheeled vehicle.

For measuring wheelbase, I would consider the ball bearing as a wheel and its center of rotation, its axle. The judges at whatever tournament you are competing in may not see it that way. The only way to be sure is to ask them.

[gh]

I believe there's a question like that on the National FAQs. How do you plan on keeping it from slipping and curving though?

[Paradox21]

I believe there's a question like that on the National FAQs. How do you plan on keeping it from slipping and curving though?

I thought it was a FAQ too but I couldn't find it. I was planning on just having it roll in the back and have my front axle do all of the steering. With one axle the vehicle can't curve .

[Dark Sabre]

I believe there's a question like that on the National FAQs. How do you plan on keeping it from slipping and curving though?

I thought it was a FAQ too but I couldn't find it. I was planning on just having it roll in the back and have my front axle do all of the steering. With one axle the vehicle can't curve .

This?
http://soinc.org/node/424

[jazzy009]

id say submit the ball bearing question to the main site (link that DS just gave). while that answer was for 3 wheels (and helpful) nowhere does it say anything about ball bearings.

[fleet130]

With one axle the vehicle can't curve

Ya wanna bet! While this may be true in theory, in the real world there are many factors that can/will cause the vehicle to from stray a straight line.

All wheels experience "slippage" in relation to the track surface. Anything difference in friction between the 2 wheels changes the slippage which in turn causes the vehicle to stray from a straight line. When one wheel goes over a "bump" on the track, it must travel farther than a wheel that doesn't. Slight variations in "roundness" or circumference will also cause problems. Uneven weight distribution from one wheel to the other has an effect. A second axle with a fixed alignment helps to minimize the effects of these variables.

[Paradox21]

All wheels experience "slippage" in relation to the track surface. Anything difference in friction between the 2 wheels changes the slippage which in turn causes the vehicle to stray from a straight line. When one wheel goes over a "bump" on the track, it must travel farther than a wheel that doesn't. Slight variations in "roundness" or circumference will also cause problems. Uneven weight distribution from one wheel to the other has an effect. A second axle with a fixed alignment helps to minimize the effects of these variables.

How would a 2nd axle stop error caused by "bumps" on the track?
As far as inconsistencies in the wheels, my wheels are commercially made so they have to be at least close right? I have never been able to fix all the other problems with my vehicle to be able to detect any inconsistencies between wheels. I will cross that bridge when I come to it.

[Dark Sabre]

The second axle helps prevent error because...

Let's just pretend that you have a second axles with 'sticky' tires on it. If your drive axle in the front starts trying to turn the car because of some imperfection on the track or if one of the drive tires is slightly different from the other, it is going to be trying to push the rear wheels laterally across the floor, rather than just forward rolling motion. Since you have a rigid frame connecting the two axles, any turning of the vehicle from one axle is partly mitigated by the friction of moving the other set of wheels .

Of course your might just be introducing more error with a second axle if you don't have them nicely parallel...

[fleet130]

How would a 2nd axle stop error caused by "bumps" on the track?

By preventing the vehicle from turning. A ball bearing wheel can go sideways (or any other direction) just as easily as it can go forward and backward! Wheels on an axle resist motion in all directions except that parallel to the plane of rotation of the wheel.