2 wheels vs 1 wheel in a linear shooter

[lcoreyl]

Originally Posted by Kusha

Does it have better momentum because of the increased contact?

Others answered, but here is the physics 1 equation:
The impulse momentum theorem

F Δt = m Δv

How much force AND how long you apply it determine your change in momentum. More contact = more time

[falconmaster]

Has anyone out there tried three wheels in a linear shooter?

[Oldbikerider]

Our team is also interested in people's thoughts and/or experiences with a 3 wheel linear shooter. If we go with a linear shooter we're thinking of allowing to add a third wheel if it should be necessary.

There are other ways of adding speed to a two wheel shooter, such as a pneumatic or spring trigger mechanism. Until we finish testing, we're keeping all options open for now.

Graham.

[Ether]

I'm skeptical that a third wheel is necessary.

My engineering intuition tells me that the first wheel should be governed at a speed approx 75% of the second wheel. You should then be able to get plenty of exit velocity without slipping.

Has anyone out there tried a speed difference of this magnitude?

[Oldbikerider]

We're hoping two are sufficient. Our tests indicate that it can probably be done with two.

I also question why a speed differential is needed. Why not just impart as much energy as you can with each wheel? We're not looking to maximize efficiency here, just fire discs as fast as possible. What is wrong if the first wheel got the disc to near full speed, then the second wheel doesn't have to do much more.

Graham.

[CalTran]

Originally Posted by Oldbikerider

We're hoping two are sufficient. Our tests indicate that it can probably be done with two.

I also question why a speed differential is needed. Why not just impart as much energy as you can with each wheel? We're not looking to maximize efficiency here, just fire discs as fast as possible. What is wrong if the first wheel got the disc to near full speed, then the second wheel doesn't have to do much more.

Graham.

By that logic why would you need a second wheel if you're attempting to impart as much energy as possible with the first wheel? As stated, the idea behind the two wheel shooter is because of the contact time between discs and wheels. If you use the first wheel to accelerate the disc and the second to propel the disc, you get comparable results to a circular shooter.

[Oldbikerider]

Our tests would indicate that one wheel is not enough. Some things to consider are how much compression is needed to impart enough speed to the disc, and how that compression effects the disc and it's trajectory.

I'm questioning why it's necessary to second guess how much each wheel will add, and why it would be necessary to have different wheel speeds for the first and second wheel. What's wrong with running both wheels at full speed. Maybe under ideal conditions, perfectly round and clean and dry disc, full speed is achieved with the first wheel, but maybe under less than ideal conditions the second wheel is needed. Under some circumstances the second wheel is just insurance.

Graham.

[Ether]

Originally Posted by Oldbikerider

I'm questioning why it's necessary to second guess how much each wheel will add, and why it would be necessary to have different wheel speeds for the first and second wheel. What's wrong with running both wheels at full speed. Maybe under ideal conditions, perfectly round and clean and dry disc, full speed is achieved with the first wheel, but maybe under less than ideal conditions the second wheel is needed. Under some circumstances the second wheel is just insurance.

You said in your earlier post that your goal was to "fire discs as fast as possible".

I interpreted this to mean "with the fastest exit velocity achievable with a given 2-wheel linear shooter" .

If that is the correct interpretation of your post, then you would want to get the maximum speed increase (change in speed) as the frisbee passes through each wheel.

Based on tests run by Team 2073, this would indicate that the second wheel should be run at a faster speed than the first, to achieve your goal.

[Ether]

Originally Posted by Oldbikerider

I also question why a speed differential is needed.

I didn't say it was "needed". I was speculating that you can squeeze more performance from a given shooter by doing so.

Why not just impart as much energy as you can with each wheel?

If that's your goal, then the first wheel should be driven slower than the second.

There's a wheel speed above which the exit velocity of the frisbee from that wheel actually starts decreasing, presumably due to excessive slipping. The first wheel reaches this point before the second one does because the frisbee speed coming into the first wheel is so much slower than for the second wheel.

[falconmaster]

I think if you can control the speed of the 1st wheel from like 40% to 75% of the second wheel, you can also effectively control the distance. Am I correct?

[Ether]

Originally Posted by falconmaster

I think if you can control the speed of the 1st wheel from like 40% to 75% of the second wheel, you can also effectively control the distance. Am I correct?

The second wheel probably has more effect on the exit speed.

[Ninja_Bait]

May I suggest the following equality:

sum("wheels") from 1 to infinity = "belt"

I know it's not really the same, but still.

[Dinoyan]

2 wheel linear shooter make your frisbees to go further

[Slartibartfest]

If you wanted a long time for contact in a linear shooter couldn't you use a belt instead of a wheel?

[Ether]

Originally Posted by Slartibartfest

If you wanted a long time for contact in a linear shooter couldn't you use a belt instead of a wheel?

This was mentioned in post #10, and also here.