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Thread: building my 084 redrive

  1. #1
    Level 1 Supporter Bart's Avatar
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    building my 084 redrive

    well here goes another project, we will see how far i get on this one. someday, i will get all my loose ends finished up on this 084 motor. but it has been an fun journey
    every since i started the build i have been looking at many different styles and types of redrives, it seems like the Arrow Prop redrive started out very strong. and then the Circle-S redrive evolved, with some better ideas on supporting the crank bearing and keeping the flex down to a minimum.
    the hardest part was to decide which type of belt, i wanted to go with, the 3/8" v-belt, a microgroove, or the cog belt system.

    the belt technology has improved so much in the last few years. 20 years ago if someone told me, that i would own a 180 hp sled, that had a cog belt in place of the chain drive. i would have told them, that they are crazy. but i have one and it is fun to ride.

    but in the past i have picked up a few different parts and pieces, for different redrives, but the game stopper was not having the way to easily build my own lower pulley for the 084 crankshaft.
    tried a turning few tapers, on the lathe, and it just wasn't happening. at least not now.
    i called up Arrow Prop, just to see if they would sell me a lower pulley only, they said no problem and the price was right. visited with their machinist. found out the dimensions that he was needing. and a while later a lower pulley showed up on the doorstep.
    the other parts and pieces, adapter plates and tension pulleys, i can make on the lathe.
    one of the other aspects that has been scaring me off, was when you cut the aluminum plate, for the frame, you make an error, you will be starting over.
    but i was looking at some different web pages,

    http://ronleclerc.net/redrive.html

    and i came across a build that one did, and he first made a mock up frame out of plywood. (and that i can do also.)
    i am starting to get a lot of things that i can do. plywood is a lot cheaper, and it will give me a pattern to cut out the aluminum when i get it finished.

    it has been a busy fall and not much time to play on these side projects, but the last couple of nights, was able to get the spacer made to mount the ring gear to the driven pulley. with this made now i can start mocking up the proto type. it may not be quick with only 1 maybe 2 evenings a week to play on this, amid all the other projects i have.
    but it is the journey of the build that makes it fun, and i will see where this evolves to.

    it was kind of fun building the spacer that connects the ring gear to the driven pulley. didn't have a caliper that would measure out to 7 inches, so after truing up the aluminum blank. we made the first step that would fit inside the pulley. it took about 40 cuts, at 2 thousands at a time. to get it there. cutting the step for the ring gear was a lot simpler, because you could see the opening. and see what we needed to cut it down to. it is just short of a press fit. and when they are snapped together. it was a nice feeling to get this part fitted up on the first try, just hope the rest of it goes as smooth.
    but finally posting something about this, helps me stay somewhat focused & on task.
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    Last edited by Bart; 11-20-2017 at 12:35 PM.

  2. #2

    Re: building my 084 redrive

    My Kinda Guy!!!

  3. #3
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    Re: building my 084 redrive

    Good job on building the top pulley. mine was flat on rear side so i had to bolt through pulley to hold it on. with the circle s they don't use the top bolt hole in engine. just the first two on either side. with that you don't have to worry about access to any bolts under pulley to tighten up and with tensioner no need to slide mounting bracket up to tighten belt. you going to make me buy a lathe with all this building going on. maybe later though. can.t wait to see your starter mounting bracket.
    Last edited by bgmcl60; 11-20-2017 at 08:36 PM.
    4a084
    Arrow belt drive
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  4. #4
    Level 1 Supporter Bart's Avatar
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    Re: building my 084 redrive

    starter mounting bracket?? that is why i am building the proto type out of plywood. last summer when i purchased a starter similar to yours, it took almost 10 times to get the holes almost close, and i still ended up playing with the shims in the starter to get the nose where i wanted it to be. my friend with the tig machine, would just shake his head, every time i would show up to get the holes filled back in.
    as for the lathe, my friend will be retiring and moving in 3 years, so i am starting to put a few pennies aside. and watching craigslist to see what comes up.
    he has been helping me tune up the little craftsman 109 lathe he sold me. and before long it should be able to turn most things that are 3" dia. and smaller. looking at fabing up a steady rest for it now. many look at it as a small toy lathe. but if you take your time, it works just fine.
    but using it will make me appreciate an larger and newer one.
    Last edited by Bart; 11-20-2017 at 09:05 PM.

  5. #5
    Level 1 Supporter Bart's Avatar
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    Re: building my 084 redrive

    it has been a few days of thought about some of the little things, it looks so simple, but it is fun with only an hour, here and there.
    so at the moment i have 4 of the six bolt holes dead on.
    the driven pulley is 4.75" diameter
    the drive pulley is 7-15/16" diameter
    the aluminum backing plate will be 3/4" aluminum
    i randomly picked up a belt that is 37.5" in circumference. per the formula. center to center should be 8.5" on the pulleys. but as you can see. there is still to much slop. and when i put a tensioner against the belt. it sucks the belt almost to the middle of the pulleys. so the belt is either longer than stated or i am not putting the correct information into the formula.
    i will try some other backing plates 8-5/8" and 8-3/4" center to center and see if that is livable.
    the other information i need to find is what the recommended belt tension is for a set up like this.
    i am used to dealing with putting so many lbs. of force against a belt, and measuring the deflection.
    i am still looking at if I can assemble this together, using just a belt tensioner, and not slotting the backing plate.
    i am wanting to use the tensioner system, so i can incorporate a cover plate and bearing on the far side of the drive pulley, this in my thinking will take any side load off the main crank bearing.
    (in looking at so many different styles on the ultralight planes with 4 stroke motors, many don't have this support. i am assuming the reason why. is because they are always rebuilding motor every couple hundred hours. so they are replacing anything that is worn out then. )
    i have some more material ordered, if i can go with what i have planned. i will need to build a 3.5" prop hub extension also.

    this sets up a little different than what you have seen with other Arrow Prop lower hubs, due to having a 5 groove pulley. ( the plywood backing plate is setting flush on the motor.)
    i could have had the pulley grooves out a little farther, and if i can't get everything to line up. i may have to order an other pulley with just a little bit more length on it. but time will tell.
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    Re: building my 084 redrive

    with the long belt you got enough room to move the top pulley up to tighten the belt but you would have to counter sink the hole for the top shaft to align pulleys if they aren't out by much. would save buying another pulley.
    4a084
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    marty bray 116 mini pro
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  7. #7
    Level 1 Supporter Bart's Avatar
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    Re: building my 084 redrive

    So I have been having fun cutting and made just a few templates over the last week. tried a few different ideas. to get the bolt holes to center up, but being off just a little doesn't work to well. pointed the ends on some bolts to make a reverse transfer punch. and it seemed like no matter what i did, there was always 1 or 2 holes that were off by 1/8".
    so finally dug out the flywheel housing. cut down a piece of plywood that would fit inside it, found out the holes in the housing are 13/32", i was drilling it out to only 3/8th of an inch, (just a little to tight).
    and there i had it, an perfect template.
    another problem that i came across was the CDX plywood was not doing to well, came across some 3/4" plywood that had 8 layers in it. much better.
    so i drew out everything on the wood side, was going to leave the laminate side facing the motor. but i spaced it out when i traced the cut out for the oil pump. so now the laminate side is facing towards the pulley.
    built a little spacer out of wood to keep the driven pulley at the correct distance.
    using the c to c at 8-13/16" it worked on the cheap CDX plywood. but way to tight on the good stuff.
    ended up trimming the 1-1/4" hole to having an 8-9/16 center to center, it fits good, and it looks like about only 3/4 belt deflection when i put the tensioner on it.

    all in all it is a better idea to make a wood template first. plywood make a lot cheaper bone yard.
    and now i getting a better idea of what i need to look out for, as i get closer to doing the real cut out.
    at the moment still waiting on some aluminum rounds & bearing. for the bearing stub that will fit on the end of the drive hub
    and also an 4" diameter round, to make the prop hub extension out of.
    at times i wish i had access to a wood lathe, and i could make these parts out of wood also. just to see what the final fit up would look like.

    the shaft that i have, for the driven pulley, we will need to turn threads out on it, to secure it to the frame.
    and last night i may came up with an idea, with using some parts on hand to use for the pulley tensioner,
    now just have to find time tonight and see if it will work.
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    Level 1 Supporter Bart's Avatar
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    Re: building my 084 redrive

    this is a picture of what Ron Leclerc posted on his web page, this is along the style that i am looking to develop,
    he ran his starting ring gear between the motor and the plywood frame, and used an concentric shaft for the driven pulley to tighten the belt.
    due to the mounting holes on the 084, this will not quite work for me. but i do like having an bearing on the other side of the drive pulley, to take any side load off the rear main journal.
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    Super Moderator Corky's Avatar
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    Re: building my 084 redrive

    Here's a pic of the circle S mating plate for comparison of the oil pump area..
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    Last edited by Corky; 11-29-2017 at 12:27 AM.

    Aluminum .120 14' X 76" hull
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  10. #10
    Level 1 Supporter Bart's Avatar
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    Re: building my 084 redrive

    last night i was looking at Txriverrat's post where he is selling his arrow prop redrive, not a bad price, for the 800 and change that they are asking for them now
    so I started adding up everything that i have up to this point in my inventory
    1 ea. 24 x 24 x 3/4" aluminum plate 50.00
    1 ea arrow prop 5 groove drive pulley 125.00
    1 ea. alum. round 3" dia. x 12" long 30.00
    1 ea. alum round 4" dia. x 6" long 30.00
    3 bearings 30.00
    1
    ea. alum. tube 2-9/16"od, x 1-1/4"id x 7" 20.00
    1 ea. alum round 7" dia. x 1" 10.00
    1 ea. alum round 7"od x 4-1/2"id x 2" 15.00
    starter 75.00
    belt 20.00
    so the total price on this with out any time or labor is 405.00.
    and i have already the driven pulley and flyweel, or there would be an other couple of hundred more on top,
    and i haven't added my time, and the lathe time into the equation.

    in reality sometimes trying to piece things together, may not much cheaper that purchasing it out right.
    but doing this keeps me out of trouble and occupies my time. and I enjoy the challenge.
    and as many say a boat is an acronym for "bring out another thousand". just glad this is a mini airboat, so it is "bring out another hundred"

  11. #11
    Level 1 Supporter Bart's Avatar
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    Re: building my 084 redrive

    later today I was visiting with a friend that has an ultralight challenger plane, and was visiting about the redrive on it, he was going to take some pictures on it, next time he was home, and show me what his thoughts were,
    the web is a great tool. so i typed in ultra light challenger and this was one of the pages that came up

    http://www.challenger.ca/support/service_bulletins.html

    i am glad i came across this link, now i realize why arrow prop makes the back plate out of steel.
    so now i will be needing to change a few ideas
    it is funny how it is the small things that can make a big difference.
    so it is back to the drawing board for a little to make sure i don't have the same problem that the challenger had to deal with that is in the bulletin.
    but i have a few ideas, that could work.
    but this might be why the Circle S redrive has an outer support for both the pulleys.
    anyway i am glad that i am still putting it together with plywood, and haven't cut any aluminum yet.
    the biggest problem will be to design the drive shaft support, to withstand the tensional pull of the belt. and here i was so worried about just supporting the lower pulley

  12. #12
    Super Moderator Corky's Avatar
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    Re: building my 084 redrive

    Yes, think about it...Without that support on both sides of each pulley the chances of them going off axis and having early bearing/belt failure goes up tremendously...With the stress those have on them it would stand to reason that the only factors in building a unit like that would be a cost,ease of manufacturer, and possibly a size issue where room is needed in the engine compartment...IMO a simple support at the end of each pulley would be well worth the effort and you could still use aluminum for the parts..
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    Aluminum .120 14' X 76" hull
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    67" Whirlwind "Razor X" prop



  13. #13
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    Re: building my 084 redrive

    In my opinion outer bearing support is critical. Without it I'm sure you will be looking at premature failure of either bearings or belt. With the degree of tension that must be applied to the belt to prevent slipping, or in the case of a cog belt, jumping; combined with the forces imposed by the thrust of the propeller the more rigidity you build in, the better. JMO
    Last edited by aerokirk; 12-04-2017 at 06:17 PM.
    11'6" Marty Bray Hull
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  14. #14
    Level 1 Supporter Bart's Avatar
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    Re: building my 084 redrive

    Ebay has been a good friend lately. and things are starting to show up.
    picked up a SS shaft, a while back. that might work for the hub extension. just removing the material so the bottom of it will center over the castle nut. and then need to fab up a 1-1/4 spacer to marry the shaft to the pulley.
    it always just sounds so simple.
    with this set up. it looks like i will need to make the sides 5" wide or something close to that.
    that is the fun part, i almost have to look, and know what the end result is going to be like, before i can start getting the measurements somewhat close.
    it seems like I will, think i have almost everything on hand for what i need, then i am needing to order some small piece or part, and things are at a standstill for a while, and i hope that in the waiting time, i don't change the plans to many times.
    if i had my own (larger) lathe & mill it would be simpler, just combining with my friend when we are both off work, and have time, can be a challenge.
    but i am having a lot of fun, just figuring out how to get from point A to point B,

    i included a picture from the Challenger hub problem. at least from what i see in the picture, the SS plate used for the adjuster, is sitting just a little inside the cutout. so only a small part of the spacer was snug against the frame, and allowing the inside plate to viberate, letting the outside of the adjusting plate to move.
    i have looked a many redrives this last week and there are many of the lower HP redrives, that have no support to keep the tension off the crankshaft main bearings.
    the only reason i can see for this, is that for many of the ultralights, the motors are always need to have an annual overhaul after so many hours.
    (crankshaft bearings that are on the 2-stroke motors can handle a side load, but the crank bearings on the 4 strokes were not designed for any side load,) and without being supported on the other side of the pulley to keep the tension off. i am thinking it is only a time thing, before you start loosing oil pressure, due to a worn out rear main bearing.


    but if i look up redrive PSRU units, i am finding a lot of different ideas that other have brought to the table.
    so it will be fun to see how this ends up.
    p.s.
    the spare shaft on the pulley came out of one of the cuyuna gear boxes, so it gives me a pattern to follow, so maybe i will be able to get the correct tapper on the other shaft.
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    Last edited by Bart; 12-05-2017 at 09:50 PM.

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    Re: building my 084 redrive

    just me thinking out loud but why couldn't you take an output shaft from a rotax gear box and use it for your top pulley support. it already has a prop adapter on it but will the shaft and bearing work? just a thought.
    4a084
    Arrow belt drive
    marty bray 116 mini pro
    weber 32/36
    solex 34 pict 3
    weber 34 ich
    Razor x maybe 3 blade

  16. #16
    Super Moderator Corky's Avatar
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    Re: building my 084 redrive

    Hey Bart are you snowed in up there ???...This is usually the time when you're out in the shop posting the project of the winter...

    Aluminum .120 14' X 76" hull
    Teledyne 4a084-4 engine
    Circle S 1.69:1 reduction
    67" Whirlwind "Razor X" prop



  17. #17
    Level 1 Supporter Bart's Avatar
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    Re: building my 084 redrive

    it has been a fun and crazy winter so far, not much snow at sea level, but man up in the mountains, already have more snow than last year. it has been a fun week off of work, just spending it with the family
    we were supposed have a bunch more snow showing up this week, but it is 35 degrees and raining, just have to see what the weather decides to do.
    i have almost all the raw parts for this redrive, just needing to get together with my friend to do a little lathe / mill work, to get the various parts turned out.

    but a month ago i upgraded finally my welding machine. ended up picking up a new Miller 215 multi-process welder, now I can mig, mild steel, ss steel, & aluminum, tig and stick weld also. then I ran some better wiring to the shed, so i don't have to string out an extension cord, all the time. just isn't fun popping breakers all the time.
    after getting the rebates, and selling my older welder, i am into this for only a 1000. and it has already been more than handy,
    nothing against the lower end mig welders, i used one when i put my first cage & frame together, but with out a way to fine tune the wire speed or amps, it was either pushing the wire into the puddle, or running a cold bead, which leaves a lot of questions on how good of weld that i actually made.
    a few weeks ago i came across an add in craigslist for an mini air boat hull, for 500. and it got me a little excited, until i got the dimensions. it had 20 inch sides, and 12 feet long, but the stern was only 4' wide and the bow narrowed to 3'. & it was made out of 3/16" thick aluminum.
    a friend has a cad program that he used to design his skiff. He punched the numbers in and it is crazy on the difference there is between a 4' wide hull to a 5' wide one. so it looks like i will be building a hull with a 5' wide base, later this spring when the snow starts to melt. (like i am needing another project)

    so even though i haven't been posting much, there has been a lot going in the background, or in my mind.
    i just hope that this spring, the weather isn't to cold & I can finish up all the loose ends on the different projects that i have going on with the 084 motor,

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