Hydrostatic ATV

[J_J]

Yes, each wheel has a hyd motor. Don't know about the pump. It probably has two, but am just guessing. It uses a joystick for steering.

 

[brokenot]

The Power Tracs look interesting, but you can see how speed limitations come into play. In the video, they say ground speeds up to 16 mph can be attained, but in their literature on the website, it says 14 mph is max. You don't see them actually do it in the video either, because with the weight of that machine and only a 25 hp engine under the hood, it won't be able to do that speed unless it's on perfectly flat, solid ground. We have four Toro Dingo mini-skidsteers at work with 25 hp Kohler engines, and they have plenty of torque for pushing, but if they were "geared up" to attain ground speeds of 14+ mph, the drive torque available would be next to nothing. There are just too many losses along the way in the power train.

When gas was up to $4 a gallon a year or two ago, I read quite a few posts on a website owned by a couple of guys that were building hydrostatic motorcycles and smaller commuter-type cars. They touted the "efficiency" of the drive systems, and said that infinitely variable transmissions were the wave of the future. While I wouldn't argue the point about infinitely variable transmissions, I would argue the hydrostatic drive isn't the way to do it. Hydrostats have been around forever, but you simply do not see them used by any manufacturer in an application where high(er) ground speeds are desired.

As for engine selection, upgrading your hp by using a car engine is an easy way to go, lots of the aerial equipment we have uses Ford's 2.3 or 2.5 engine rated at 80 hp or so. When using a car engine though, lots of folks forget about these cheap or free engines not being equipped with a governor of any sort. You might think you can stay on top of the engine rpm as speed and/or load changes by controlling the throttle yourself.....but you'll stay pretty busy trying. Our stuff uses electronic governors which are available for around $500. Another less-expensive option, would be to find a mechanical belt-driven governor from something like an older forklift. Long story short: If you don't have a governor dealing with changes in engine load on something like this, you'll either be constantly killing the engine, or over-revving the engine.....or both.

 

[evo803]

This is not exactly what you are looking for, but this is an articulating,oscillating AWD vehicle for someone in a wheel chair not nearly as fast as you want but will suit many other of your needs.

YouTube - New Style ATV

 

[kdlklm]

This is not exactly what you are looking for, but this is an articulating,oscillating AWD vehicle for someone in a wheel chair not nearly as fast as you want but will suit many other of your needs.

YouTube - New Style ATV

yes that is very much what I'm looking for, and I have seen that before. But it requires the user to transfer into the machine. Which I would like to be able to avoid.

 

[kdlklm]

The Power Tracs look interesting, but you can see how speed limitations come into play. In the video, they say ground speeds up to 16 mph can be attained, but in their literature on the website, it says 14 mph is max. You don't see them actually do it in the video either, because with the weight of that machine and only a 25 hp engine under the hood, it won't be able to do that speed unless it's on perfectly flat, solid ground. We have four Toro Dingo mini-skidsteers at work with 25 hp Kohler engines, and they have plenty of torque for pushing, but if they were "geared up" to attain ground speeds of 14+ mph, the drive torque available would be next to nothing. There are just too many losses along the way in the power train.

When gas was up to $4 a gallon a year or two ago, I read quite a few posts on a website owned by a couple of guys that were building hydrostatic motorcycles and smaller commuter-type cars. They touted the "efficiency" of the drive systems, and said that infinitely variable transmissions were the wave of the future. While I wouldn't argue the point about infinitely variable transmissions, I would argue the hydrostatic drive isn't the way to do it. Hydrostats have been around forever, but you simply do not see them used by any manufacturer in an application where high(er) ground speeds are desired.

As for engine selection, upgrading your hp by using a car engine is an easy way to go, lots of the aerial equipment we have uses Ford's 2.3 or 2.5 engine rated at 80 hp or so. When using a car engine though, lots of folks forget about these cheap or free engines not being equipped with a governor of any sort. You might think you can stay on top of the engine rpm as speed and/or load changes by controlling the throttle yourself.....but you'll stay pretty busy trying. Our stuff uses electronic governors which are available for around $500. Another less-expensive option, would be to find a mechanical belt-driven governor from something like an older forklift. Long story short: If you don't have a governor dealing with changes in engine load on something like this, you'll either be constantly killing the engine, or over-revving the engine.....or both.

I think I've come to the reality that my top end speed will be closer to 15 mph than 25 mph. But 15 mph is pretty quick. I still want quite a bit low-end torque for pulling stuff and maybe even having a three-point hitch on the back.

 

[kdlklm]

Yes, each wheel has a hyd motor. Don't know about the pump. It probably has two, but am just guessing. It uses a joystick for steering.

is there any possible way you would be able to find out what motors they use, just so I can get an idea of what I'm looking at.

 

[Hozen]

Have you given the thought of having electric moters instead of hydraulic moters power the wheels? Hear me out on this. Electric motors supply loads of torque and you could use a much lower HP engine to supply enough amps to keep everything running.

I haven't crunched the numbers, but I've long had an idea to use a small lawnmower engine to turn 4 alternators to supply enough amps to run electric motors. A couple car batteries would be needed as well, of course. You could probably get your 25mph you want and still have the torque without all the heat. Essentially, you'd be making a hybrid ATV of sorts. Electronic "throttle" controls already exist on the market.

An electric golf cart might be a good place to start. Then, add the engine and alternators to continuously replace the power.

 

[kdlklm]

Have you given the thought of having electric moters instead of hydraulic moters power the wheels? Hear me out on this. Electric motors supply loads of torque and you could use a much lower HP engine to supply enough amps to keep everything running.

I haven't crunched the numbers, but I've long had an idea to use a small lawnmower engine to turn 4 alternators to supply enough amps to run electric motors. A couple car batteries would be needed as well, of course. You could probably get your 25mph you want and still have the torque without all the heat. Essentially, you'd be making a hybrid ATV of sorts. Electronic "throttle" controls already exist on the market.

An electric golf cart might be a good place to start. Then, add the engine and alternators to continuously replace the power.

that has been one of my considerations, it was in one of my previous posts. My concern is getting motors that can handle water and mud without having to enclose them too much. Electric motors to heat up a lot when they are put with a great deal of load. They do lack low-end torque without a huge amount of amps. But I haven't ruled the idea out yet.

 

[brokenot]

I think I've come to the reality that my top end speed will be closer to 15 mph than 25 mph. But 15 mph is pretty quick. I still want quite a bit low-end torque for pulling stuff and maybe even having a three-point hitch on the back.

Gotcha.

Keep in mind though that even 15 mph is going to be stretching it. In that Power Trac clip, they made it clear that they had no "attachments" available for it....such as a blade mount/three point/etc. Sounds (to me) like they made all the compromises they could in order for it to attain an "ATV-competitive" top speed, (and 14-16 mph isn't really competitive anyway), and sort of abandoned the notion that it's suitable for real work.

On another forum I frequent, one of the topics frequently discussed are issues with lawn and garden tractors. Breakdowns and lack of reliability are common discussions. The overwhelming majority of "issues" are experienced by the operators that are continuously asking too much of the machines. A good rule of thumb, is to consider what attachments the tractor manufacturer offers for a particular model. Lots of these guys buy a tractor and then build their own trailer, (that's too big), to pull around behind it, or they hook up to a large spike aerator, (and then add a bunch of weight to the tractor for traction), and try to drag it around. They can go right to the manufacturer's website or sales brochure and see that all that's listed for accessories for their model is a light-duty yard cart, and somehow that doesn't register.

In Power Trac's situation, I think the fact that they don't offer attachments is very telling. It certainly "looks like" it could be a real workhorse, but....

 

[evo803]

Search for the Ventrac series 300 they have done something also like you want.