Best motor/gearing option to drive a shooter?

[Ether]

Originally Posted by Djur

5200 rpm CIM geared at 1.5:1 => 7800 rpm. He rounded that up.

Who said they are running it at full voltage ?

[ehochstein]

Before we can answer the question of the best motor/gearing option, we need to determine the ideal exit speed.

[Ether]

Does anyone have any data (actual measurements) for the following?

1) what effect do different shooter wheel speeds have on frisbee flight path (e.g. height at the target distance) ?

2) how much does your shooter wheel slow down when a frisbee passes through it ?

[Aren Siekmeier]

Your best bet to determine any of this is to put together something with a launch speed in the desired ballpark and test the desired shot. Then you don't need any math beyond knowing how things scale. We have run all of our tests off of a UPS (uninterruptible power supply) so that we can adjust the voltage to get the desired launch speed. Knowing this speed makes it much easier to design the final mechanism, and we haven't needed any frisbee flight models, only repeated testing.

Of course, we are not simulating any shooter spin down with a UPS, but as already mentioned, leaving headroom for speed control should take care of this.

[Ether]

Originally Posted by compwiztobe

We have run all of our tests off of a UPS (uninterruptible power supply) so that we can adjust the voltage to get the desired launch speed.

Did you gather any data (that you'd be willing to share) during this testing?

[Aren Siekmeier]

Not that I have access to at the moment. When I get into the shop this afternoon I'll see what I can dig up.

[Ether]

This post has some useful qualitative observations:

http://www.chiefdelphi.com/forums/sh...2&postcount=55

[smclean1969]

Something for the 8000 rpm, that's assuming free spin, which isn't accurate for a motor under load conditions. The CIM has to turn the wheel, so it's going to be something less than 8000. It won't be an amazing drop but 7000 - 7500 is probably more reasonable.

[Ether]

Originally Posted by smclean1969

Something for the 8000 rpm, that's assuming free spin, which isn't accurate for a motor under load conditions. The CIM has to turn the wheel, so it's going to be something less than 8000. It won't be an amazing drop but 7000 - 7500 is probably more reasonable.

Could be a lot less than that if the wheel is generating vibration and windage.

Hint: measure the CIM current with a clamp-on ammeter. Then estimate the CIM speed from the voltage and current, as shown here.

[Ether]

Originally Posted by Ether

Could be a lot less than that if the wheel is generating vibration and windage.

Anybody planning to buy 8" pneumatic and run it at 8000 rpm read this thread:

http://www.chiefdelphi.com/forums/sh...d.php?t=111118

[MrRiedemanJACC]

Is there anyone considering using dual banebot 550's to drive their shooter?

[ToddF]

Yes.

[neshera]

FWIW, World's record for fastest frisbee throw was 74 mph in 1988 (citation: YouTube video from Guiness Book of Worlds' Records TV show)

[Aren Siekmeier]

Note that with any no-slip one-sided design, the tip will have to be going twice as fast as the desired exit velocity, since half of the imparted velocity must go into spin. So even if we only need a 70mph launch, the shooter would need to be going 140mph.

Add in a second side, however, and that changes entirely...

[Ether]

Originally Posted by compwiztobe

Note that with any no-slip one-sided design, the tip will have to be going twice as fast as the desired exit velocity, since half of the imparted velocity must go into spin.

http://www.chiefdelphi.com/forums/sh...8&postcount=36