# Aeromarine 60hp V-Twin Engine

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#### pictsidhe

##### Well-Known Member
The Valley Engineering drive had about six hard rubber balls in ports that functioned as a one way device, not belt slip.
The one way torque is via belt slip

#### soupercooper

##### Well-Known Member
HBA Supporter
I just carefully looked at valley eng. redrive assembly video and looks to me the rubber balls are used for a torsion spring for the tensioner pulley and as a belt tensioner as well? i dont see it serving as any one way device or one way clutch? i see they used 3 separate poly-v belts instead of one wide belt, im sure there is some advantage to do it that way?, love to learn why? maybe its a redundant system? three belts are better than one? if one belt fails there is two left to get you home? so if the rubber balls serve two functions that's pretty clever? maybe the rubber balls serve as a dynamic tensioner for the belts instead of traditional static tensioner adjustment as well as dynamic tensioner for tensioner pulley? here is the video link.

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#### rv7charlie

##### Well-Known Member
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.

Charlie

#### Air Trikes

##### Well-Known Member
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.
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.

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#### rv7charlie

##### Well-Known Member
Vassili,

On your website, I saw one mention of your drive adapted to a Yamaha 3 cyl Genesis. Do you sell, or would you be willing to develop, bolt-on packages for the Yamaha snowmobile or watercraft engines? The 4cyls seem to be very close to the weight of the 3cyl, with significantly more power, and the little 2 cyl engine at ~70-80 HP seems to be light enough to replace Rotax 503/582 engines. Current offerings from other vendors often use overrun clutches, which I can't get comfortable with.
Thanks,
Charlie

#### Wild Bill

##### Well-Known Member
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.

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#### Vigilant1

##### Well-Known Member
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.
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

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#### soupercooper

##### Well-Known Member
HBA Supporter
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.
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.

#### soupercooper

##### Well-Known Member
HBA Supporter
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.
"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.

#### soupercooper

##### Well-Known Member
HBA Supporter
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
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.

#### rv7charlie

##### Well-Known Member
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.

#### soupercooper

##### Well-Known Member
HBA Supporter
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.
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!

#### pictsidhe

##### Well-Known Member
Culver props is now run by a granddaughter. Good to see that something was kept running.

#### soupercooper

##### Well-Known Member
HBA Supporter
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.

Charlie
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.

#### TFF

##### Well-Known Member
She does the props; I believe her husband does the ULs.

#### soupercooper

##### Well-Known Member
HBA Supporter
She does the props; I believe her husband does the ULs.
if your referring the backyard flyer they quit that as well sad to say. they made a statement on their website not not going to sell design, tooling or jigs to anyone either.

#### pictsidhe

##### Well-Known Member
How sad. Hopefully Alaina will carry on doing the stuff the guys no longer will.

#### TLAR

##### Well-Known Member
Yes, 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.
This is incorrect. I own one, and it does not behave as described

#### pictsidhe

##### Well-Known Member
This is incorrect. I own one, and it does not behave as described
It's not going to be easy to tell.

#### Tallyho

##### Member
Just watched the video on the valley assembly. Seems pretty simile. The balls are just a spring for the idler pulley. Bit of pre-load setting it up to stop the belt slipping. Then as the tension on the belt changes as the engine runs it allows the change in load to be damped by the springs. Shouldn't be any slippage and any resonances would be damped. Same as a sprung idler on a car engine accessory belt just in a nice compact form. Clever.