# Aeromarine 60hp V-Twin Engine

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#### Air Trikes

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

#### pictsidhe

##### Banned
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

##### Well-Known Member
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.

##### Well-Known Member
Log Member
This is going to put a dent in the DP1 O100 sadly... Bet then again the DP1 does not need a redrive...

#### soupercooper

##### Well-Known Member
HBA Supporter
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

##### Well-Known Member
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

##### Well-Known Member
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

HBA Supporter

#### Yellowhammer

##### Well-Known Member
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.