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Thread: Redrive belt tensioner ideas

  1. #1
    Junior Member Bart's Avatar
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    Redrive belt tensioner ideas

    In building my own belt redrive for the 084 motor, I have been going over the web for over the past year looking at the different styles that manufactures and others have posted.
    there are the two main different styles.
    the simplest way is to have elongated slots on the backing plate, and just have another plate on the below it with tensioning screws or bolts like the Arrow Prop & HoverHawk designs
    http://www.hoverhawk.com/hovercraftkits.html
    http://www.arrowprop.com/rdrive.htm

    these would work if i was to keep my flywheel on the crankshaft pulley. and i may have to revert back to keeping my 14" flywheel on. that is why i have the pulley center to center at 8.5 inches. just and escape clause.
    but i still would have to have an separate, stationary bracket to mount the starter motor to.

    but i am giving it a go with installing an starter flywheel on the driven pulley. so with this it is not to feasibly to use the backing plate that can be adjusted, but will need to install an tensioner of some style.
    below are a couple of ones that have impressed me, but some have pros and cons.

    there is the circle S style, but I have heard a lot of complaints about the belt slapping, at certain RPM's. with out ever seeing this type first hand, it leaves me with the main question. what is making the belt stick to the cogs. at least that is about the only explanation that i can think of, but with a V-belt set up i shouldn't have that problem. I have dealt with this type of tensioner on all of the snowmachines that i have owned. and they have been bullet prof, until the chain gets to much slack, and then it can really get exciting.

    there are a couple of other styles that i have included pictures of, one is made by Gates, an automotive tensioner for a 2" wide belt. for 60 dollars off of Amazon. it is pretty tempting to go that way. all there would need to do, is fab up an extension mounting plate. and then i would always have consistent spring loaded belt tension.

    Culver Props also has an very interesting concept on belt tensioning that they have incorporated . on their VW setups, about 10 minutes into the video, you will see the design that they have came up with. I still need to contact them, just to see if they would sell the tensioner only. and if i would be able to incorporate it on my build. but i have only 1/2" space between my flywheel and the backing plate. and i think that this isn't quite wide enough. but with a phone call away that would answer those couple of questions.
    https://www.youtube.com/watch?v=O3iRfk8QCdQ

    i have included pictures of what i have done, with the original starter motor, then i upgraded it. this is with using direct drive.
    and then below are some pictures of a few different styles of tensioners.

    the biggest reason for building a redrive, or as many others who do purchasing it. is that with a direct drive, i am limited to how many RPM's the prop is rated for, not many are for more than 3100 like the ultra prop. and from what i am learning, many of the other props are giving their best torque at around 2100 to 2400 RPM's, and i just cant see leaving almost the top 1000 to 600 RPM's of this motor laying on the table.

    feel free to comment on what your experiences have been if you are running an belt driven redrive
    thanks for reading.
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    Last edited by Bart; 02-05-2018 at 03:03 AM.

  2. #2
    Super Moderator Corky's Avatar
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    Re: Redrive belt tensioner ideas

    Bart I just posted some pics in your redrive thread before I realized this was here so I'll post the pics again...This is the Circle S tensioner...Simple, but NOT effective for the most part......This really needed some more time spent on it to get a working design..I'd have paid a little more for an updated part that worked...Aerokirk is simply tying his back out of the way and not using it...
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    Aluminum .120 14' X 76" hull
    Teledyne 4a084-4 engine
    Circle S 1.69:1 reduction
    67" Whirlwind "Razor X" prop



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