2013 - Turbine powered hydrostatic launch craft

[sp_1989]

Front hub update

Of the two hubs I ordered, one was fairly true, the other was quite off. Since I didn't think I could cut off the original flange without destroying it or the tube, I decided to just put the adapter on as true as I could and go with that. After I welded the adapters on, I drilled five new holes for the wheel studs.
(Please excuse the ugliness of my welds. )

 

[OzFab]

(Please excuse the ugliness of my welds. )

For safety reasons, you may want to go over those welds again...

 

[sp_1989]

Front hub update part 2

Fabroman,
Good idea. I think the back welds are ok, but I'll go over the front welds again.

Today I worked a little more on the hubs:
The original studs that came with the hubs were 1/2" but when I measured the wheels I have, they were 9/16". Somehow I thought I needed to have 9/16" studs/bolts for the wheels. I later thought to try the 1/2" studs and found that they will actually work just fine. So, I put them in the holes (which were 9/16") and then put the wheels on. I snugged them up and checked if they ran true. They were off centered a bit because of the over-sized bolt holes, so I loosened them up and adjusted the fit. I did this until they were centered, then I welded the studs in place to the hubs, like original. Since the hubs I bought were 4 bolt, I only could do 4 of the 5, so I'll need to get 2 more.

 

[sp_1989]

Ok, as to the hydrostatic drive part

I have this hydrostatic drive unit off the transaxle of the Deere 185 tractor/mower. I disassembled the transaxle and kept the hydrostatic drive unit intact. I am trying to figure out how to use this. I'd like to test it first, hooking it up to some motor to spin it and then running the lever back and forth. If I could determine the ratios, I'd know if it would be practical or not. Has anyone used something like this?
Will this unit run on it's side?
Any suggestions or WAC ideas?

 

[sp_1989]

Posting like crazy today

Ok, more pics.
This differential was inside the above mentioned transaxle. At first I was planning on using it, but I don't think it would be easy to do in this situation. I'd LIKE to be able to, but the original axles, although 1" dia at the wheels, step down to a smaller size. PLUS, they are too short for this two-person kart.

I really wanted to post the pics though because I think they're just neat to see.

 

[machinist@large]

Careful now.....

I have this hydrostatic drive unit off the transaxle of the Deere 185 tractor/mower. I disassembled the transaxle and kept the hydrostatic drive unit intact. I am trying to figure out how to use this. I'd like to test it first, hooking it up to some motor to spin it and then running the lever back and forth. If I could determine the ratios, I'd know if it would be practical or not. Has anyone used something like this?
Will this unit run on it's side?
Any suggestions or WAC ideas?

Don't tear the hydrostat down if you've never worked on them before; also, make sure before you test it that none of the fasteners that held it to the final drive/ differential also hold it together, otherwise when you test it the hydraulic pressure could cause it to uncontrollably disassemble itself. It won't explode in the traditional sense, but it will make a big mess, plus you would have to try to find and reinstall all the little pistons

I don't know if you'll be able to set the pump assembly on the bench without the differential attached; many of these types of drives use the whole housing as the reservoir for the system; the problem is that I can't be any more specific than that due to not being that familiar with that unit. Also, do the pipes coming out go to a separate pump, or are they for auxiliary functions like a lift mechanism of power steering?

On most transaxles of this size the pump and the drive motor are contained in the same unit; the pump is where the input pulley is consisting of a variable displacement swash plate axial piston pump that is controlled by the directional linkage on top of the unit. This feeds pressurized oil to a fixed displacement motor in the appropriate direction for forward or reverse.

Ok, more pics.
This differential was inside the above mentioned transaxle. At first I was planning on using it, but I don't think it would be easy to do in this situation. I'd LIKE to be able to, but the original axles, although 1" dia at the wheels, step down to a smaller size. PLUS, they are too short for this two-person kart.

I really wanted to post the pics though because I think they're just neat to see.

If you had access to a lathe, or, even better a friend who is a machinist you could machine longer shafts for the unit. Your only other option would be to use it as a jack shaft drive for the final axles.

Hope this was of help.

 

[machinist@large]

OK, maybe........

On closer look, you may be able to bench test just the drive, provided you know where the external line go and can simulate the system when full of oil and bled of air. I would still make sure that the pump/ motor section isn't dependant on the diff. housing as the reservoir. Do you have a schematic for the transmission? How about the tractor in general?

 

[landuse]

Of the two hubs I ordered, one was fairly true, the other was quite off.

I would have sent that back for another one...

 

[fowler]

What ever u do don't pull apart the pump or motor

Piston pumps are something that many big workshops dont even touch
They get people who specialise just in piston pump/ motors

It's very easy to mess it up with tolerances like nothing else

The trans may run without the diff and axles but remember the more oil u have in there the cooler it will run

If u separate it all then u may require a cooler

Also u will find it very hard to calculate ratios as there are non

It is simply a pump pushing a motor

Unloaded it will spin at a set ratio, but unloaded info is not useful
As u load it the rpm drop and the torque increases as pressure rises
Until u hit relief pressure and

What u will have to do is measure rpm at minimum swash and max swash
Then take a stab from there

Or find the exact specs on this hydro drive

 

[sp_1989]

Hydrostat stuff

Wow, good responses and info.

I was curious about the inner workings, but I'm glad you all warned me away from taking a peek.

As far as I can tell (is that AFAICT?), the hydrostat drive unit has a separate fluid reservoir from the transaxle. The hose goes to a plastic reservoir that I'll have to mount higher than the top of the unit. There is no pressure on that line.

So there shouldn't be any problem running it on it's side?

I don't have any schematics for anything from this mower.

And as far as returning the wobbly hub, if I had paid attention BEFORE I cut off the welded on studs, I probably would have sent it back. I just got a bit ahead of myself.

 

[fowler]

Yes that tank is just for replenishing oil
Is there a second line going to that tank?


Just make sure the unit is mentioned to be full of oil in operation

If it has a set level like 1/2 or something then u will find the pump pickup is out of the oil if u flip it
But if it is meant to be topped up then its good to run at any angle
As long as it has good enough seal

 

[sp_1989]

Yes that tank is just for replenishing oil
Is there a second line going to that tank?

No second line, just that one. I went on Deere's website and looked at the powertrain. Not much new info there.

Do I just use hydraulic oil for the hydrostat?

 

[machinist@large]

No second line, just that one. I went on Deere's website and looked at the powertrain. Not much new info there.

Do I just use hydraulic oil for the hydrostat?

Bummer on the lack of info; do you have any pics of what the tank to hydro looked like before you pulled it? I'm guessing that you should be OK bench testing it if you can reattach the reservoir and bleed the air out of the system with the pump in the correct orientation (i.e. the way it was originally mounted). Once the system has been bled, the unit won't care about how it sits; once it's full of fluid (no air) it won't care as long as the res. is higher than the rest of the unit.

For the correct fluid, Deere's web site should be able to tell you what it takes. Try calling the dealer as well. I'm hesitant to make a recommendation because I've seen some take hydraulic oil, some take motor oil, and some take ATF. Some don't care what's inside, some it's extremely critical..

 

[sp_1989]

The engine runs!

Here are a few pics as I was disassembling the 185. You can see the reservoir and the cooling fan.

I'll give the dealer a call tomorrow.

I worked a bit on the engine, cleaning up the carb and gas tank. I put it back together tonight and tried to start it. I ended up using some starting fluid, but once it started, it kept running, so I think I'm in good shape with the engine.

 

[sp_1989]

Dealer parts guy said "Low viscosity Hy-Gard". Less than a qt. So I'll pick some up after work.

 

[machinist@large]

Dealer parts guy said "Low viscosity Hy-Gard". Less than a qt. So I'll pick some up after work.

I had a feeling that would be the dealer recommendation, that's JD's brand name for "Universal Tractor Fluid". Basically it's a combination gear oil/hydraulic fluid; what most people don't know is that most ag and const. equipment uses the same oil in the transmission(s) and the hydraulics; it lets them use the gearbox housing as the reservoir for the hyd. system. It makes packaging much easier. It's also extremely high class oil. The Case-IH brand name is Hy-trans. Cat uses it too, but we'll have to wait for fowler to chime in for more details.

I hope they sell it by the quart for you; I always buy it in multiples of 5 gal. or more; a whole farm fleet oil change takes just under 75 gallons. Just a "top up" can take 5~10 gallons.

 

[sp_1989]

Turbo power

Yeah, I have a 5 gal bucket of Hy-Tran for the Red machines and a 5 gal bucket of Hy-Gard for the Green machine. I didn't have any low-visc. though. I picked up a qt for about $6 today. I'm taking tomorrow off work (hopefully) so maybe I can try it out.

 

[sp_1989]

Hydrostat test

Ok, I tested the hydrostat unit. I had the unit upright to fill new fluid and I was turning it by hand. The fluid finally went and bubbles came back up, so I think that's a good thing. I kept adding and then left some in the reservoir and put the cap on.

I then turned it and bolted it down and put the belt on and bolted down the engine.

After I got the engine running, I tried the lever back and forth so see what would happen.

Not much. The output shaft didn't turn at all. I held the lever one way,, then the other, NOTHING!

So, I guess scratch the hydrostat part...

 

[fowler]

What sort of noise did it make?
Anything?
Any odd crunches or pings?

At least something should happen

Unless it wasn't bled properly

What happens if u fire it up and turn the output my hand
Kinda push start it

 

[sp_1989]

What sort of noise did it make?
Anything?
Any odd crunches or pings?

At least something should happen

Unless it wasn't bled properly

What happens if u fire it up and turn the output my hand
Kinda push start it

I didn't notice much noise, but the engine was pretty loud. I didn't notice anything at all happening.

As far as bleeding it goes, I suspect I didn't do it right. I just poured the fluid in until it stopped. I did this while it was in it's original orientation and only spinning it by hand. Is there a bleeder port maybe?

I can try giving it a push while running. I didn't take the setup apart yet just in case there was something else to try.