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Re: [Small4-strokeEngines] Re: Generac engine mounts [2 Attachments]

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  • ron ohler
    HI norman, It appears that you have the prop centerline out some 5 or so from the mounting plate. Is the prop shaft only 1 or so in diameter? What are you
    Message 1 of 41 , Jan 11, 2013
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      HI norman,
      It appears that you have the prop centerline out some 5" or so from the mounting plate. Is the prop shaft only 1" or so in diameter? What are you using for bearings?
      Best,
      RonO
      --- On Tue, 1/8/13, Norman Heistand <nheistand@...> wrote:

      From: Norman Heistand <nheistand@...>
      Subject: Re: [Small4-strokeEngines] Re: Generac engine mounts [2 Attachments]
      To: Small4-strokeEngines@yahoogroups.com
      Date: Tuesday, January 8, 2013, 12:41 PM

       
      I have been experimenting with belt redrives for many years. I have tried HTD cog belt, PolyV belts, and banded 3vx belts. I like the 3vx belts setup the best due to low cost and long track record of flying. See the attached picture of my design on a snowmobile engine. I use two steel 1x1in square tubes to the engine mounts, two aluminum angles to bolt to a plate. Two mounted bearings and a 1 in jackshaft. A QD bushing type single groove pulley as a prop hub. Both the prop hub and the back end of the jackshaft have 1/4 in aircraft bolt through the shaft so pusher or tractor thrust is secured. Major advantages are low cost, light weight (drill a lot of holes in the cast iron pulleys), and no real failure mode. I use an auto belt idler to increase the belt wrap around the drive pulley and adjust belt tension. With 3in and 6.9in pulleys I get 2.3 ratio. I use a custom 1.5in aluminum tube with 10:1 tapered bore to adapt to the snowmobile engine shaft. See the attached photos.

      I will build and sell one of these redrives for $450 which is a great price. The exact engine mount specs are needed and the power shaft specs. The photos show 2.3 ratio drives on 6500rpm engines. A 1.7 ratio would be better for the 3600rpm engines. This would simply be a smaller driven pulley and a shorter belt.

      Norm Heistand

      On Tue, Jan 8, 2013 at 11:08 AM, E <homeplane@...> wrote:
       
      Jason I think you are on the right track. Look at the large engines that use belt drives. 2 plates with 3 bearings pulleys between the plates. this could be scaled down to generac size. 1/4"thick plates would be enough to carry the loads. the back plate bolted to the engine the frount plate bolted to the rear plate,but not with long bolts and spacers but with 1/8" plates. use a micro grouve belt and a spring loded slack adjuster to take care of back lash. this is how i will build my own for my air bike single. I have a g10 allso 95 lbs direct drive sounds pretty good. E.


      --- In Small4-strokeEngines@yahoogroups.com, "Jason" wrote:
      >
      > How about an external link between the crank and the prop shaft that would be adjustable for tightening the belts and have a sealed bearing at either end. I intend to try this method on my G10 project. It should take all of the belt load from the crank and would make for easy belt adjustment. It would require a hinged type mount between the engine and prop shaft. Any thoughts?
      >
      > --- In Small4-strokeEngines@yahoogroups.com, "dagwodzz@" wrote:
      > >
      > > Allan, Its very easy to over tighten the belt on a redrive. Doing so
      > > displaces the oil needed to float the crank. Look in the photo section here
      > > to see what it looks like.
      > > The PTO bearing will carry the upward pull load, thus allowing the plain
      > > bearing in the crank case to relax. It will also help to keep the crank from
      > > flexing under the belt tension.
      > > Cheap peace of mind. I have one left from this production run. I had 8 made
      > > to keep cost down. Later, the one offs will cost more unless I get a few
      > > more who would like one.
      > > Price on the unit is $109 plus shipping around 10 bucks.
      > >
      > > DAG
      > >
      > >
      > >
      > >
      > > -------Original Message-------
      > >
      > > From: Larlaeb Jones
      > > Date: 1/8/2013 8:26:02 AM
      > > To: Small4-strokeEngines@yahoogroups.com
      > > Subject: Re: [Small4-strokeEngines] Re: Generac engine mounts
      > >
      > >
      > > Very nice, I will certainly consider that. My plan is similar to the Kolb
      > > but lighter and with more drag. I doubt it will come in under the 254lbs,
      > > probably more like 300 or so. Is the exterior bearing you suggested also
      > > meant to be crank friendly?
      > >
      > >
      > > Thanks,
      > > Allan
      > >
      > >
      > >
      > > On Tue, Jan 8, 2013 at 8:22 AM, dagwodzz@
      > net> wrote:
      > >
      > >
      > > Morning Allan, I might suggest a 3 blade prop for your project. Your crank
      > > will thank you for it. If I may give a shameless plug for my DAGSTER prop.
      > > It was designed for slower flying ultralites. The wide 6.5 inch profile at
      > > the 75% station just flat works. The 3 blade will smooth out the the V twins
      > > firing cycle. Its a ground adjustable design witch will be re handy at some
      > > point.
      > > If you are still of the 2 blade mind set it can be had that way as well.
      > > Its built for me by GSC. Its built around their 100 HP model. In other words
      > > .... Strong.
      > >
      > > See it here.......... Http://www.flickr
      > > com/photos/13761775@N00/sets/72157629697290242/show/
      > >
      > > DAG
      > >
      > >
      > >
      > >
      > > -------Original Message-------
      > >
      > > From: lar23016
      > > Date: 1/7/2013 6:48:25 PM
      > > To: Small4-strokeEngines@yahoogroups.com
      > > Subject: [Small4-strokeEngines] Re: Generac engine mounts
      > >
      > >
      > > Actually I am just beginning to do that. I have a 67X35 two blade wooden
      > > prop which is what Valley suggested for me but so far I've only run it up to
      > > about 3100. I need to add some better anchors to the stand before I try for
      > > full throttle.
      > >
      > >
      > > --- In Small4-strokeEngines@yahoogroups.com, "dagwodzz@" wrote:
      > > >
      > > > Hi Allan, I'm guessing your not running a prop on the test stand....
      > > Right?
      > > >
      > > >
      > > >
      > > >
      > > > -------Original Message-------
      > > >
      > > > From: Bart Ferguson
      > > > Date: 1/7/2013 4:28:50 PM
      > > > To: Small4-strokeEngines@yahoogroups.com
      > > > Subject: Re: [Small4-strokeEngines] Generac engine mounts
      > > >
      > > >
      > > >
      > > > Hi Allan. Dag over on the PPC Builder's list runs a Valley Redrive on his
      > > > Generac for his Dragonfly which is rubber mounted, Get a hold of him for
      > > > more info. Bart
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > >
      > > > From: lar23016
      > > > To: Small4-strokeEngines@yahoogroups.com
      > > > Sent: Monday, January 7, 2013 4:13 PM
      > > > Subject: [Small4-strokeEngines] Generac engine mounts
      > > >
      > > >
      > > >
      > > >
      > > > Hi All,
      > > > What's the current thinking on mounting the Generac? I'm aware that at
      > > > Valley Engineering they mount direct to the frame on their backyard flyer
      > > > and one or two of the PPC groups are doing that too. However, I've had
      > > some
      > > > local feedback from users who have not had as good of an experience with
      > > > that approach on their Kolb with vibration and broken engine bolts and
      > > such.
      > > > The aluminum frame (which is mainly bolted together) on my plane is
      > > probably
      > > > weaker than that steel tube cage so I'm curious if some sort of shock
      > > > absorbing mount might be better for me. I'm using the Valley re-drive and
      > > it
      > > > runs pretty smooth on the test stand. Thoughts and suggested approaches to
      > > > experiment with this would be welcome.
      > > >
      > > > Thanks,
      > > > Allan
      > > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > > FREE Animations for your email - by IncrediMail
      > > Click Here! â–º
      > >
      >


    • Dan
      I ve been able to get my puter to work again and updated my e mail address. I used to fly an original firestar with a 377. A four stroke would be nice on a
      Message 41 of 41 , Jan 11, 2013
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        I've been able to get my puter to work again and updated my e mail address. I used to fly an original firestar with a 377. A four stroke would be nice on a little kolb. Any info would be nice.
        Dan

        --- In Small4-strokeEngines@yahoogroups.com, "George Bearden" wrote:
        >
        > Dan, I'm having trouble reaching you via email.
        >
        > GeoB
        >
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