Manual Clutch for Horizontal Shaft Motor

[Danny Downs]

Anyone interested in a manual clutch for a horizontal shaft motor? It would be similar to a slide on centrifugal clutch, but would allow the user to operate the clutch with a cable. This would allow the user to have much quicker starts, feather the clutch around turns, burn-outs, donuts, decompression braking, etc. As far as I know, nothing like this exists...
Thoughts?

The links below show one of the first prototypes that we've developed, and additional pictures of the renderings for our first set of production parts. The unit is a 3/4" crank bore 14 tooth #35 chain sprocket.

Clutch Photos:

http://i.imgur.com/Qzb81gR.jpg
http://i.imgur.com/mj4l7Ac.jpg
http://i.imgur.com/4JiMpFQ.jpg
http://i.imgur.com/JkYzWb4.jpg

Also, here's a video of the clutch in action!

http://www.youtube.com/watch?feature=player_embedded&v=9DXW6k73b5Y

http://www.youtube.com/watch?feature=player_embedded&v=_E14X_aGrYk

Feedback would be greatly appreciated!

[John Matthews]

Interesting piece, kinda like a DD for clones.

But, can you gear the kart to do anything besides burnouts? If you run a competitive gear for most tracks I can see it just stalling the motor. Also what about emergency stops?
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John Matthews
Heartbeat Power, LLC.

[Danny Downs]

[Jim McMahon]

Might be of interest to people with direct drive two stroke motors to simplify starting. Will need to be able to withstand a peak of about 34HP with peak RPMs of 19-22K though. Ideally it would need to fit under a carb on a rotary too...

Not sure why you would want it for a clone/similar pull start kart though. IMO would be best if it wasnt designed to slip too much but was more of a binary unit. Otherwise it becomes another tuning tool, which then adds to the expense either in swapping out/modifying parts or testing to find the best combinations.

lol @ burnout video BTW. I'll cross post your links on some other forums that people tend to run the direct drive 100cc stuff. There's also some talk of people going towards the SudAm motors which are 125cc direct drive.
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[Danny Downs]

Jim,

Thanks for the feedback and I would love it if you could show our product to people on different forums. Feel free to PM me and point me in the right direction.

The clutch really does work more as a binary unit. With our stiffer springs, even our light duty 3/4" unit is capable of 80 ft-lbs of torque before slipping. It operates just like you would expect a motorcycle clutch to work, except for a single speed motor. Speaking from the testing that we've done and feedback from others, the clutch really does have advantages when it comes to racing, especially on starts and through tight turns.

[Justin Martin]

I would love a Sudam motor to be tag legal... Man they sound great, and they are cheap! Bad move not allowing the watercooled motor in the states!

AS for this clutch, it is a good Idea. I feel it would be best (at least for TaG, specifically Rotax) for starts. You could slip the crap out of it and keep the rpm at 12k-ish. Your start would annihilate the competition. With proper use you could slip around corners at max corner speed, yet keep RPM a couple K higher, this would allow a "kers like" jump out of a corner.... Too early release however would send you spinning asap.

[Danny Downs]

Justin, Agreed.

It would definitely take some practice to get used to using the clutch, but it does provide some serious benefits like the ones you described. Bottom line, faster is better

Also, what size crankshaft bore do most rotax TAG engines have. Is it the tapered 9/16" crank? Or do they run a standard 3/4"?

[Justin Martin]

Hmm, I dont recall, and I REALLY do not feel like pulling apart my rotax today, lol.

The only problem is that this clutch would be highly illegal almost everywhere. "IF" you did have it and you raced some less-strict club races, they would surely outlaw it the second it proved to have a HUGE advantage.

It would be super bad ass to have a "KERS" system though.

With modern day Lipo batteries you could set up a simple system.

One way clutch, hydraulic actuated. This would come off of a normal 4 wheel brake system, however instead of front brakes it would go to the clutch. This would allow you to adjust the differential between electric motor braking VS your actual brake. It would rapidly charge an on board lipo, yet when hitting a button you could easily add 3kw of power (or ~4bhp). The beauty of electric motors is that they double as a generator. with a hydraulic clutch there would be no added resistance during normal engine power.

Very simple system, could possibly be very light weight too... just need the funding!

PS, 3KW of power is SUPER easy to obtain, shoot I would wager 4-5KW would even be pretty easy. In the RC world you can get a 4+KW electric system that weight ~5-8 pounds including batteries, the clutch would add another ~2-3. So for an extra ~10 pounds and be able to get 4-6 extra bhp, totally worth it! ( I currently run about 50 pounds of weight anyways.)

I beleive it would add that little bit extra for the TaG class. Sometimes I feel like TaG needs a tad bit more excitement. It is exciting already, however I would like a little bit more strategy involved.

[Danny Downs]

Are there open classes in racing? And what do the rules specify in terms of clutches?

[Danny Downs]

PS Brilliant idea Justin, I think you should pursue that!

[Justin Martin]

Classes are very strict. There are usually open classes in very few places across the states.

However if there were a simple KERS system available or ~$400, many outlaw club races would pick it up in a heart beat! Who knows, it might even catch on with a larger scale. I mean Karters are constantly bragging about being the closest thing to F1. Why not continue to pursue technology? Its already available! an F1 kers system weighs ~50 pounds yet produces 80BHP for quick bursts! Now I know we can't reach that kind of performance or efficiency, however even with modern day RC electronics we can get 5-13 horse for less than 10-15 pounds. We all run weight anyways...

The nice thing about this system would be that it would require almost no maintenance. Brushless motors have no maintenance (besides maybe occasional bearings) and possibly clutch pads.

I like your Idea as well, however it would be very hard to maintain smooth control, and it would be too much of an advantage with almost no disadvantage. (IE, weight)

[Brian Degulis]

I like new ideas but I'm not seeing the benifit to this one. Take a shifter kart and select a gear that gives you a ratio close to TAG. Then go try it in that gear using the clutch as you describe. I think you would find dificult to drive and slower than a TAG. I think the centrifical clutch does a better job than you could with a manual clutch. I think that's why the dirt bike crowd sometimes uses slipper clutchs. I'm not sure if ones ever been used on a shifter I know it's been talked about.


Brian

[Danny Downs]

It would have advantages for non-shifter karts thats don't have a rolling start. You could jump off the line much quicker than a centrifugal clutch. Let's say a centrifugal race clutch was set to launch at 4k RPM, I could dump my manual clutch at 6K RPM and burn you every time. Plus, I am able to set my stall speed to whatever RPM I would like. I could pull the clutch in around a tight turn, and pop it out to get a burst of speed just like someone using a shifter kart would.

A trained driver with a manual clutch is capable of outperforming a driver with a centrifugal clutch on tighter tracks no question about it. That's why these guys keep bring up the rule book, because it would give you an advantage.

[TJ Koyen]

[Brian Degulis]

Yeah we aren't drag racing karts. Does anyone slip the clutch in a shifter?



Brian