Chinese guys are very talented to copy something without permission. They name it "reengineering" or "German engineering". I was selling these gearboxes some years ago. Some steps ahead were done for these years... Contact me if you need good not expensive gearboxes for different engines.no that price is a complete package as seen in photo, stand alone redrives i found are $1500 to $2000 range. but i got a reply from them saying "currently not available" i responded to ask when they are available, i think they are the middle man and I will try to find direct source, maybe its Subaruair but like a previous post subaruair not to be found lately. i have photos of stand alone gear and belt redrives from alibaba source of price range of $1500 to $2000 from 4 different models. i read its china mfg. but German engineering. attached is one of four varieties of stand alone redrive at $1500 to $2000 range, these will be ALOT easier to import than engines! been there done that, dealing with EPA is the killer when importing engines! they mentioned they can make adapters for other engines, there is not much out there for prop redrives besides of course rotax. and a couple others like the one for inline 4 piston yamaha engine from I forget the name right now.
Here's a post by billski giving his view on the function of the balls in the Valley Engineering PSRU. There are other posts on the subject at the linked thread.IMO, the balls serve as damped springs. Likely lighter than a coiled metal spring, and will have some damping action that wouldn't happen with a metal coiled spring. They supply both the static tension (aligning the marks at installation) and dynamic damping during torque reversals.
funny i was just visiting your website last night and looking at what you had to offer, price seem attractive as well, I ran into a dead end with chinese version. so I would be interested in a quote for an adapter to gaokin engine to your drive, i have 3D CAD model of goakin engine to develop an adapter for your drive. i will contact you...thanks.Chinese guys are very talented to copy something without permission. They name it "reengineering" or "German engineering". I was selling these gearboxes some years ago. Some steps ahead were done for these years... Contact me if you need good not expensive gearboxes for different engines.
"he" as in aeromarine are in fact using gaokin engines, the Gaokin is a knock off of the rotax you speak of. to my knowledge you cannot get new rotax version engines, only sold new OEM TO CAN AM I believe. you can find rebuilt or used rotax version engines on ebay or other sources pulled from can am snowmobiles, this is the snowmobile version not the UTV/ATV version thats has the unwanted CVT and gearbox not needed for aircraft application.I was under the impression that the engine he is using is not the gaokin.
I looked at pictures trying to find similarities between various engines. He mentioned can am engines in SXS type vehicles.
If you pull up images of the Rotax HD-8 HD-10 engines they look like what he is using.
valley eng. came up with some clever stuff, too bad when gramps passed that the family let it all die with him. thanks for sharing the correct thread on this subject.Here's a post by billski giving his view on the function of the balls in the Valley Engineering PSRU. There are other posts on the subject at the linked thread.
Torsional Vibration and Resonance - Basic Theory and Issues
backyard flyer is gone, big twin is gone, I only assumed redrive is gone as well, website is still up on these items but when you click on a link it goes to a statement of no longer in production, i think only thing alive is culver props division?, i would love to see if redrive still avail!Is that correct? Is everything gone, or just the Big Twin? The core engine for the Big Twin is no longer produced, so it's not surprising that it wouldn't be available, but their website still seems to be up.
I totally agree on the poly-v belts trapping air, that is why the Goodyear Gatorback came to be, it is cross grooved like a gators back to release trapped air, its now owned by Continental Tire under "Elite" brand name, I dealt with this issue developing superchargers for automotive. without a Gatorback belt you could hear a standard belt whistle, most thought it was was coming from the supercharger but it comes from both devices that whistle sound you hear unless you switch to a Gatorback. It obviously must be patented? unfortunately I don't think the Gatorback design is available for the wide and short redrive belt application we need.IMO, the balls serve as damped springs. Likely lighter than a coiled metal spring, and will have some damping action that wouldn't happen with a metal coiled spring. They supply both the static tension (aligning the marks at installation) and dynamic damping during torque reversals.
I don't know if it's applicable here, but some of the 'old school' cog belt drives used multiple belts to 'let the air out'. A wide belt on a fast-turning pulley can trap air between the belt & pulley, causing it to float off the pulley & increasing wear on the cogs.
This is incorrect. I own one, and it does not behave as describedYes, you are!
The valley engineering idler works like a one way clutch. Once belt tension exceeds a certain level, it springs in and let's one side of the belt go slack. The belt then slips a bit. Managing TV is tricky. The system needs the natural frequency out of the useable speed range. If oscillations do build up, they can very easily reach the point that something breaks. Slippage is one way to deal with that. If you don't have a 'slippable' connection somewhere, you have to be really, really careful. Many if not most amateur sized systems are 'soft' natural frequency is below idle. But a misfire at idle or even accelerating during startup can put the drive into the danger zone. Slip of something is one way to deal with that for short periods.