Aeromarine 60hp V-Twin Engine

[Air Trikes]

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

Yes Charlie, RX-10 is going to be my next engine

 

[pictsidhe]

There won't be slip for positive torque. It will slip when negative torque exceeds a certain amount. Very easy to test that. Lock the engine somehow and pull the prop forwards.

 

[rv7charlie]

Not a valid test; your pull test will be unavoidably slower than the varying torque (+/-) of the engine, and the mass vs spring rate of the system. Same applies to the springs in an automotive clutch disc. You can easily bottom out the springs with less torque than the engine's max torque, but it never happens while the engine is running.

But others will have to try to convince you from now on...

 

[pictsidhe]

And others.

 

[addicted2climbing]

This is going to put a dent in the DP1 O100 sadly... Bet then again the DP1 does not need a redrive...

 

[soupercooper]

RE: Valley Engineering Belt Drive
So the balls can dampen in both directions? where a spring steel torsion spring can only dampen in one direction? I'm trying to figure out what advantage the rubber balls have over a torsion spring? in this case?

 

[rv7charlie]

I wish a real engineer would jump in. I can only offer my 'redneck' take on the engineering. My understanding is that a steel spring has no damping at all, and that rubber *can* have some damping effect, because there will be some 'scrubbing' effect as the rubber compresses (and spreads out), and decompresses. It absorbs some of the energy because it's converted to heat. Of course, that means that it can't be 'springing' (by very much) constantly, or the heat will kill it. The good thing is that if it's designed right, it won't need to. (See below.)

Having said all that, I suspect that the damping effect isn't as important as keeping of the resonant frequency of the *system* (regardless of method), outside its normal operating range. Other threads, by real engineers, cover it a lot better than this uneducated redneck ever could. My understanding is that the critical thing is to keep the system out of resonance.

Again, my interpretation; hopefully a real engineer will clarify. If you haven't read it yet, Billsky does a great job here:
Torsional Vibration and Resonance - Basic Theory and Issues

Charlie

 

[wanttobuild]

RE: Valley Engineering Belt Drive
So the balls can dampen in both directions? where a spring steel torsion spring can only dampen in one direction? I'm trying to figure out what advantage the rubber balls have over a torsion spring? in this case?

The balls dampen in both directions. the plates are pre tensioned. good system but there are other ways to accomplish this

 

[soupercooper]

looks like gaokin engines restructuring their product line and obsoleted the 800cc and other sizes for WITHOUT CVT and gearbox option(snowmobile version). looks like only available now are WITH CVT and gearbox(motorcycle/UTV version) which will not work in aircraft application, i believe all that's available are existing inventory and surplus until all bought up and exhausted. go to gaokin website and see for yourself, many model engines now gone. it cost me over $650 and still climbing to import one engine, not worth it, this project im my experience has hit a dead end for the future. having difficult importing engine dealing with government on EPA and CARB requirements as well.

 

[Wild Bill]

What is the difference between the engines with and without a CVT? Do they have different crankshafts?

 

[karmarepair]

What is the difference between the engines with and without a CVT? Do they have different crankshafts?

Generally, the CVT case is integral with the engine case, so there is no easy way to get rid of it.

 

[Wild Bill]

Admittedly I haven’t seen one in person or found a whole lot online.
But I have seen pictures of the engines used in SxS utility type vehicles with the CVT transmission removed.
I’m familiar with other engines using a CVT and all that I know of have a removable CVT unit.
They simply bolt on with a few bolts.
What I don’t know is if the engine cases or crankshafts are different depending on application.

From what little I found online these engines look interesting. Mainly because compared to other V twin type engines they don’t have a giant heavy flywheel. And they are relatively compact for the HP

 

[mullacharjak]

I wish a real engineer would jump in. I can only offer my 'redneck' take on the engineering. My understanding is that a steel spring has no damping at all, and that rubber *can* have some damping effect, because there will be some 'scrubbing' effect as the rubber compresses (and spreads out), and decompresses. It absorbs some of the energy because it's converted to heat. Of course, that means that it can't be 'springing' (by very much) constantly, or the heat will kill it. The good thing is that if it's designed right, it won't need to. (See below.)

Having said all that, I suspect that the damping effect isn't as important as keeping of the resonant frequency of the *system* (regardless of method), outside its normal operating range. Other threads, by real engineers, cover it a lot better than this uneducated redneck ever could. My understanding is that the critical thing is to keep the system out of resonance.

Again, my interpretation; hopefully a real engineer will clarify. If you haven't read it yet, Billsky does a great job here:
Torsional Vibration and Resonance - Basic Theory and Issues

Charlie

I have been on this forum quite often and fit the category you refer to..Engineers cant explain to a layman.Gene smith being an exception and he explained in one of his interviews how it worked.He said the drive was not a clutch but worked like one.The engine torque and prop inertia work in opposite direction.If there is imbalance between the two and it builds up in magnitude it can be destructive.He explained that if the reaction of the prop is somehow cancelled to zero half of the reaction being gone there would be no vibration.He accomplished this by tensioning the belt on slack side with the rubber balls.When the prop tries to get ahead of the engine between the firing pulse the ball tensioned belt loosens allowing the prop to free wheel and the prop can not transmit any force to the engine crank.Seemed like a very good explaination to me.

 

[pictsidhe]

If I'd ever seen Gene's explanation, I'd have quoted it. I clearly did a poor job of explaining how this drive works myself.

 

[karmarepair]

Admittedly I haven’t seen one in person or found a whole lot online.
But I have seen pictures of the engines used in SxS utility type vehicles with the CVT transmission removed.
I’m familiar with other engines using a CVT and all that I know of have a removable CVT unit.
They simply bolt on with a few bolts.
What I don’t know is if the engine cases or crankshafts are different depending on application.

From what little I found online these engines look interesting. Mainly because compared to other V twin type engines they don’t have a giant heavy flywheel. And they are relatively compact for the HP

Gaokin Moto(GK Motorcycle and Engine manufacturer)

Gaokin Power develops,manufactures,markets and delivers the world's most reliable and cost-effective powertrains, drivetrains and parts for motorcycle,snowmobile, all terrain vehicles,Side-by-Side Utility vehicles.Welcome to Gaokin Power.

www.gk-engine.com

Take a look for yourself. I cannot tell from the website what the crank end looks like, because in their current offerings, it's hidden. If you're buying one of these engines from China, you'd be paying for and shipping a bunch of stuff you don't need - that's what I read SuperCouper's caution to be saying. And Gaokin will NOT sell direct to individuals, but you can use AliBaba to find resellers/distributors that MIGHT. But if Soupercouper is right, that source will dry up soon for engines like the one he bought (and Ken Armstrong, and Chip Erwin before him).

Maybe better to look on E-bay for Running Take Outs from junked UTVs/ATVs/Snow machines. It will take some digging, but here's a place to start ATV, Side-by-Side & UTV Engines & Components for sale | eBay

There are several sources for belt drives that MIGHT fit an engine of this type you might find on E-Bay.
Skycruiser Manufacturing Inc - 4 Stroke Parts

Belt Reduction Drives for industrial air-cooled engines and Subaru EA81 Engines

Bolt-on belt reduction air drives for Airboats, Hovercraft and Aircraft, fits Briggs, Predator, Kohler and Subaru EA81 Engines

hoverhawk.com

Air Trikes: Engines and Conversion Kits.

Reduction Drives – Lone Star Hovercraft

lonestarhovercraft.com

 

[soupercooper]

nd

I have been on this forum quite often and fit the category you refer to..Engineers cant explain to a layman.Gene smith being an exception and he explained in one of his interviews how it worked.He said the drive was not a clutch but worked like one.The engine torque and prop inertia work in opposite direction.If there is imbalance between the two and it builds up in magnitude it can be destructive.He explained that if the reaction of the prop is somehow cancelled to zero half of the reaction being gone there would be no vibration.He accomplished this by tensioning the belt on slack side with the rubber balls.When the prop tries to get ahead of the engine between the firing pulse the ball tensioned belt loosens allowing the prop to free wheel and the prop can not transmit any force to the engine crank.Seemed like a very good explaination to me.

this is the best explanation yet to date, THANK YOU, and in laymens terms as it should be IMO thank you again, I contacted valley eng. to see if they would be interested in selling the design or something and not let this clever design die, if not then we need to reverse engineer one, who has a valley eng. drive available so we can reverse engineer it?? this design truly seems to have some merit to it to not allow it to die with grandpa Gene!

 

[soupercooper]

attached photo of what belt drives air trikes sells, but mostly for rotax engines and few others?, but nothing for industrial briggs/kohler engine or goakin engine. air trikes specialty is gear drives and can tailor to your needs in that regards, but again Ace aviation is making belt drives for briggs/kohler and goakin engines but would nice to have alteratives.

 

[soupercooper]

Goakin engines came in three forms, where there was WITH CVT and gear box option, and without CVT and gear box and now its only an INTEGRATED CVT and gear box option, no longer able to remove CVT and gearbox, here are photos of comparison of the three. they seem to discontinue snowmobile version (without cvt and gearbox) and only have motorcycle version (with integrated CVT and gear box). as shown in attached photos. but this is only based on speculation of what Ive seen in changes to Gaokins website and was also told by Kevin Armstrong (our founding father of goakin aircraft application) as well. I discovered these engines came to be from Hisun Motors of China and USA (UTV/ATV vehicles) cloned from rotax v-twin engine from Can Am UTV/ATV vehicles and stemmed from it is Goakin engines making many forms of engines for many industries now not just UTV/ATV. BUT looks to me goakin is downsizing back to just UTV/ATV and motorcycle engines BUT they have a VERY interesting 800cc twin FUEL INJECTED 2 -stroke engine for aircraft (and one other application) as shown in attached image at 100 HP !!! at only 77 pounds! again fuel injected and water cooled, but its off subject as its a 2-stroke, this is a 4-stroke thread.

 

[soupercooper]

it may not be even worth importing engines from china on a very small scale like I did (1 each), add shipping, brokerage, customs, warehouse handling, tariffs, taxes fees once arriving at USA port are passing the cost of the engine itself!! and in the end AFTER paying all these fees (well over $600) it can get impounded by the EPA and CARB, its no longer worth it in IMO!!

 

[Yellowhammer]

Rotax has the engines for what we all are looking for. The four stroke ACE engines and the plethora of four strokes they make at least one would suffice as long as the particular were figured out.