Need help with a turbine project

hillberg

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Look at the Dixie chopper, A turbine powered riding mower (all hydrolic drive), A note on the T 10 excess load rates will cause compressor stalls, Had a Bell 212 on a start if the outside air temps were too high the GPU would pop and growl. That's a narrow limit,
 

baronpilot

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Thanks Don. Again, I like hydraulics, but not interested in a 15 MPH golf cart. I want to go at least 50 MPH. Doing that with hydraulics will be near impossible.

I think loading any single stage centrifical compressor too quickly is a problem, but I'm not sure you would get compressor stall. If I remember correctly compressor stall happens when the relative wind through the turbine changes rapidly causing an angle of attack exceeding the stall angle on the blades. In my old Iskra fighter jet I would get compressor stall anytime I would pull more than 6 G's in a turn greater than 70 degrees and 300 knots indicated below 9000 ft or so.
 

baronpilot

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BTW - what make and model governor is in our Helicycles?
 

baronpilot

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OK - here is how I think it needs to work. The turbine runs at 60k and the output is 12k. There is a gear kit available that further reduces the output to 6k.

Next, a pully style CVT will work, but it has to be modified. First the engine needs to have a speed control/governor unit that idles at maybe 4500 RPM output speed and then runs up to 6000 RPM in the same way the helicycle does through a pot. The drive pulley on the CVT needs to have a stall of maybe 5500 RPM so that it does not engage until the engine crosses this RPM. Now, on a normal "snowmobile" CVT the increasing RPM makes the pulley compress to a higher gear ratio. This will not be possible of the turbine since it will run a constant RPM, so instead the pulley must change gear ratio mechanically either through a direct linkage through the gas pedal or some type of fast-response elctro-mechanical device. As the drive pulley increases in gearing the driven pulley will automatically change ratio as well. Finally, an overunning clutch would have to be installed to immediately release driving power to clutch once the throttle is disengaged. The trick will be designing and building the mechanical mechanism to make the driving pulley increase and decrease in gear ratio.
 

WHY

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Todd

The "double variable speed pulley on the Simplex was on a "hinged" jackshaft and had a rod that went down to a foot pedal. When the foot pedal was "kicked" all the way down at the heel it pulled the jackshaft so low that the belts went slack " disengaged" then when the pedal was tripped to "level" it was in low, then when you "forced it into "toe down" it was in High. If you wanted to, you could "gentley" force into toe down and it went thru a wide range of ratios as this cause the inner part of the double pulley to move slowly thru the range.

Tony
 

baronpilot

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Tony,

Just watched a video of the old Simplex. Pretty neat stuff. They used a fixed rear pulley and the clutch worked just like the driving pully on a snowmobile, but as you stated the ratios were changed manually like I would require. They also used some sort of idler pully to keep the belt in tension whereas as snowmobile clutch does that automatically through the driven pulley.

I think I could make something like this work.
 

baronpilot

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As you might be picking up, once I latch on to something I can't quit until I have it figured out.

This video shows how the driving pulley can be changed manually. The meat of the video starts at roughly 1:05. In the fully disengaged position the belt would not be riding on the pulley and would simply rest on the shaft. As the pulley is squeezed together the belt engages and as it is squeezed further the gear ratio climbs. As this happens the driven pulley has a sensing cam in it that causes that pulley to spread apart further increasing the ratio.

The beauty of this system is the fact that the engine could be started up and run right to full operational RPM without engaging the clutch. The cart would only start moving when you manually moved the driving pulley in. When you let off the gas pedal spring pressure would move the pulley back out.

This got me thinking... If I found a snowmobile that produces roughly 100HP, could I take out it's CVT system (and maybe use the transmission as well) and midify the driving pulley so that it does not automatically change pulley size? This would really be ideal.

http://youtu.be/7joHS-z40CU
 

baronpilot

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I think I just hit pay dirt. It seems that Team Engineering not only builds CVTs for snomobiles and ATVs, they also build the transmissions for the ATVs along with the differentials and they are designed for 100HP. The only modification I would have to make is manual control of the primary pully.

The most cost efficient wat to proceed would be to find what ATV's use their CVT, transmission, and rear diff and order those parts. Then send out the primary to a shop that can modify it to be manually controlled.

This would also solve my problem of reverse since the transmission is built with full gear selection.

http://www.team-ind.com/products/transmissions-transaxles/ots-main-transmission/

http://www.team-ind.com/products/traction-control-systems-differentials

http://www.team-ind.com/products/cvt
 

PW_Plack

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I dunno...I think Mike's idea in post #9 was the winner. Electric! It's the ultimate CVT. Just ask railroad engineers!
 

baronpilot

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Yea, electric would be nice and could easily be done if you were happy with 15 MPH, but to get any real speed the motor would have to be 3x the size and you would have to run a real generaotr set with it. Cart would weigh aboout 3,000 lbs when finished.

With the parts I mentioned about this is almost an off-the-shelf solution requiring only the primary pulley being modified and placement of the driveline into the cart.
 

ylf

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I have to agree that a mechanical connection from engine to wheels is always more fun to drive.
 
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