clutch?

[Sandman]

whats the possibilities of using a clutch?
Snowmobiles use a primary and secondary clutch to move the sled forward...would a system similar work for an airboat? or would it reduce the torque too much? or cause too much shaft flex and uneven bearing pressure?
Just a thought...

Edit:
it would allow for max rpm on the engine before it grabs at the prop but I'm sure it would reduce your ability to run the prop at extremely low rpms. Usually once the clutches grab you can lower the rpms of the motor and still maintain slower speeds on a snowmobile.. so it got me thinking...
Watch out... bring extinguishers ...

[Sandman]

This type of clutch system... for an airboat??
I don't know.. honestly I'm lost at most of the reduction stuff atm... just throwing this out there... because I do understand the snowmobiles a bit more than I do airboat drive systems.

http://www.wheatfarm.com/snowmobile/images/image4.jpg

edit:
The transmission system is a CVT or Constantly Variable Transmission. The front pulley houses a variable clutch system that utilizes a spring and set of weighted arms that change the effective pulley size based on speed and torque requirements.

[Duane Scarborough]

Sandman,

I am a little familiar with the CVT. Its also used on go carts and 4 wheeled ATVs.

Using one on a mini airboat is an interesting idea. It may work just fine, but a simple reduction drive works too.

Duane

[Sandman]

this system would allow for reverse.... hmmm....
well for a Frankenstein build... it might be something fun to mess with.

[Sandman]

I was out today and I scabbed some parts off the old Arctic cat that might go towards a build at some point... hard to decide what will... and won't be good for an airboat... so I've started a pile of stuff that may apply to a build later on.
I was looking at the gear box of the arctic cat, not sure if it would make a good reduction for the 032... but an old skidoo one might be better.
The older sleds gear cases were multiple chain sprockets for the drive gear with an adjustable tensioner.
Maybe as a temporary unit until I find one that works best.
Ideally a belt system would be smoother and quieter but I need to do something to feel like I'm moving in the right direction... any direction.
I'll need to look around for a prop hub so I can a good look at how they mount to a shaft and hopefully I can get my motor back together again soon so I can make a test platform to work from.

[buster]

Sandman,

I'm not sure what you may come up with using snowmobile drive parts, but I have just enough experience with them to be dangerous. I would advise you to pay real close attention to your prop speed. They are prone to disintregrate when revved beyond their Max. rpm.

Back in the late sixty's, when I was still ten feet tall and bulletproof, I built a "Minibike" out of a 13 HP JLO engine, and twenty feet of square tubing. I used all the snomobile drive pulleys also. WHAT A RUSH WAY TOO FAST, AND TRICKY TO HANDLE for a machine three and a half feet long

Dave

[Sandman]

nice!
sounds like fun for a young boy!!
I'm an old faaaaht these days... just young in the mind
I thought about using the drive gears backwards of their original design. Or back n forth until I figure it's a go or not. Mostly I'm interested in the shafts and gears because I'd like to mount my motor low in the hull and run belts up to a prop shaft.
using a primary clutch off the crank then a belt to a secondary clutch on the prop shaft. most snowmobile nuts know how to tune the clutches for grabbing at different rpms... so My goal (seeing how I live in a snowmobile rich area) would be to talk to the people here about rpms and how to tweak the clutches for a steady smooth grab and constant velocity at the goal rpm. ( no idea what that goal is yet)
I've seen video footage of airboat props coming unglued on high rpms... scary stuff for sure.