Hydrostatic transmission

[Master Hack]

Before ya all start piling on, it has been well established that hydrosatic transmissions are not suitable for high speed and/or high power applications. They do however work well in applications like ride ‘em mowers and low speed yard junk.
l’m planning Naughtagator V2.0 and want to use one for that. It has variable forward and neutral and reverse.
Someone smarter than be tell me if this will work.
The trans has a vertical input shaft. Its easy enough to find an engine with a vertical crankshaft.
Rather than using a V belt between the two, l propose stacking the engine on top of the trans with a flexible coupling between the two, and the necessary support for the engine.
l can’t do the fancy sketches some can, so use yer imagination.This is the coupling l’m referring to:


Lets hear it….

 

[Denny]

They do wear out quickly in dirty environments. But proceed.

 

[Master Hack]

They do wear out quickly in dirty environments

Huh? I’ve never worn one out. Ran one on a log splitter for 20 years with zero maintnance. I guess “dirty” is relative.

maybe you used a chinese knockoff? I think those are called Ruvjooy cuprings

 

[Thepartsguy]

Huh? I’ve never worn one out. Ran one on a log splitter for 20 years with zero maintnance. I guess “dirty” is relative.

maybe you used a chinese knockoff? I think those are called Ruvjooy cuprings

musti1 just connected two 20hp Briggs crankshafts together to make a 40hp 4 cylinder Briggs engine with lovejoys and it didn’t shake itself apart. Not that exact lovejoy coupler a beefier one but I don’t see why it wouldn‘t work to run a hydro.

 

[Thepartsguy]

Ahh found it ahaha.. I knew it had been done couldn’t remember where. Anyway youtube rat rod style gokart build from scratch is the exact video of a guy doing this with what he had layin Aboot. Could be fun.

 

[ezcome-ezgo]

Those transaxles are designed to be run that way right? The input shaft sticking up?

 

[Master Hack]

Those transaxles are designed to be run that way right? The input shaft sticking up?

Yeah, this one is anyway.

 

[unreal]

The love joy couplings don't like any misalignment but they will last forever

 

[Master Hack]

The love joy couplings don't like any misalignment but they will last forever

Alignment might be the biggest challenge. Other than that l can’t see a reason why it won’t work. I hate dealing with belts.

 

[G.W]

I'll be building a lawn mower/kart with one of those soon

 

[Snaker]

Before ya all start piling on, it has been well established that hydrosatic transmissions are not suitable for high speed and/or high power applications. They do however work well in applications like ride ‘em mowers and low speed yard junk.
l’m planning Naughtagator V2.0 and want to use one for that. It has variable forward and neutral and reverse.
Someone smarter than be tell me if this will work.
The trans has a vertical input shaft. Its easy enough to find an engine with a vertical crankshaft.
Rather than using a V belt between the two, l propose stacking the engine on top of the trans with a flexible coupling between the two, and the necessary support for the engine.
l can’t do the fancy sketches some can, so use yer imagination.This is the coupling l’m referring to:

View attachment 141246
Lets hear it….

Hydro's are used in farm tractors (big ones) and other various industrial equipment.
So there is a scale of design to make something that holds up.

I get the impression that your talking about a riding lawn mower design that you may be adding to additional loading?

Lets say that the hydro is putting out the desired rpm range but is fragile to the expected loading.
I have a notion about a sort of driveline modification.
That would be to add inline gearing to first down gear coming off the hydro and then up gear back to desired rpm range.
I'm thinking that the down gear / up gear would be sort of a protection for the weak hydro.

Maybe if extra hp is added, the downstream gearing wouldn't help any ways?
I've asked different engineers about this but never really got a straight answer.

 

[Snaker]

As far as the couplings go, sure it would work, its what they're designed for.
Just pick one with specs that match your setup.
A double chain with two sprockets make a coupler as well.

 

[Master Hack]

The hydro was salvaged from a ride’em mower with a 15 hp Kohler. I have a 5hp engine i plan on using. Weight might a little more than the mower but not a huge difference.
All this thing will be used for is putting around the clandestine mountain top labratory campus, with my fat a$$ and a few tools.
Top speed is unimportant, fact is if it tops out at 10mph that would be perfect.
The biggest advantage to this hydro (other than it was free) is the reverse and differential functions.
Duty cycle would be no more than 5-10 minutes at a time.

 

[G.W]

Sounds perfect, mat e even a little over kill for your application. People build mowers like I'm planning on and they run crazy engines at high speeds and the axles last for a while.

 

[Master Hack]

This is the, POS errr ahhhh l mean junk pile treasure of which l speak.