Me and LAWMAN have been doing some serious thinking about building a couple two seater buggys. And we will most likely go all Toy running gear, however this thought has come up, why not full hydro ? I'm talking full hydro in the sense of individual wheel hydro motors, and hydro steering, coilover susp. Think about it a bit before the flame throwers come out. You could get away with a 40HP Diesel or so engine attached to a pump, almost any crawl ratio you wanted, and could set it up so the wheels could spin 90 degrees ( now thats crab walkin ). You could come up with parts fairly easy ( fork lifts, e-z lifts, and heavy equipment ) I don't know jack about hydro set-ups except my hydro assist on my toy. So this is like way out there for me, but someone must have alot of experience with full hydro vehicles and apply it to rock crawling. Maybe someone has already discussed it or is working on it right now, anyway just a thought ....

hey, i have also thought that this might be a good idea. I have seen full-hydro setups like that on construction equipmeant, and the only reason i can think of not to do it, is streetability. So i say go for it, and keep us informed!!

i say at least check into it. sounds like a fat idea and thats where the next step comes from. hell i might even check into it.:D

just found this
Check out the DT series motor
white Hydraulics (http://www.whitehydraulics.com/catalog/catalog.asp?showpage=ce.html)

I've done a lot of thinking about this too. for strictly crawling i think it would be the ultimate setup! the biggest down side i have come up with is the lack of tire speed. sometimes you gotta use a little go pedal! even if the hydro motors could handle some speed, 40hp aint gonna cut it. So you go with a bigger motor, bigger pump, bigger hydro motors to handle the increased power.......starts getting heavy quick! Someone will find the balance someday and when they do it will be an awesome setup! Try it. if it works i'll copy it :flipoff2:

Hey daniel, check the bottom of that chart, the 2K1 model makes 29,580 lb-inches intermittent. Can you just divide that by 12 for lb-ft?? Maybe there's a more complicated conversion. But, notice how the max. RPM of each motor goes down as the max. torque goes up... According to my calculations, a 40" tire needs about 504 revolutions to go 1 mile. Now, the 2K1 model has a max. speed of 40-50 RPM. So that means you could only go AT MOST 10 miles an hour. As for bumping over ledges and doing steep hill climbs, i honestly have no idea what hydro-motors are like to drive, so i dunno...

would a hydraulic motor act similar to an electric motor, as in "all torque, no horsepower"?? If so, then it might be really cool on the rocks...

It's funny that you post this because my dad (Old Syko) has been talking about this same thing for the last few months. It doesn't sound bad. I just like a V8 to much:D
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Build it

Try to find a skid-steer being parted-out for a base.

I have a Case Uniloader (skidsteer) and mine has a 4-cyl
cummins 60 horse motor. this unit uses a Sunstrand
pump for each side. the pumps are mounted inline of
each other. valving is handled at the pump itself.
the final drives are geared down quite a bit thru the use
of sprockets and chains to the final drives. this is of course
way different than the hub-mount hydro motors which are
capable of rotating (steering). do your math though, cause
you won't want a rig only capable of doing 6 mph like most
skid steers..........

--that little loader has enough power to knock over a house
though....

--Sherpa

There was a guy built and competed in the European 4x4 trials championships in Switzerland in 2000. Very small machine but was 100% hydro. I only saw it in practice, but it was sure very manouverable, but was crap at long steep climbs. He also put in hydro controled suspension so he could pick up wheels and shit.

Overall it was a good machine, but make sure you got enough power.

I think the future of 4 wheeling is in hydraulics. The baja trucks already run hydro accesories off their V8 engines. I don't know about hydro drive, but I would love to build a fully independent portal rig with a Kenetic hydro suspension(full independent wheel travel control), full hydro steering, and hydro winches. This setup could kill but would take lot of R&D as well as money!

Jeep had the Commander concept that had a hybrid engine and wheel located electric drive motors. I think individual electric drive for each wheel would be a great setup. Plus you have max torque at idle!

Not that I would follow through with building a full hydro buggy, I've been thinking about that a lot too. In fact, while some friends and I were at the Cal Rocs event this past weekend, it was one of our main discussion topics. The main advantage I see is the high ground clearance. What brought the hydro drive to mind was the ship (ocean going vessel) container moving equipment. Talk about portals, those rigs have about 15 feet of clearance under them. I think the main draw back would be the lack of wheel spin on demand and the massive hydraulic reservoir and cooling system that would be needed. But maybe for a competition only vehicle, you could ignore the continuous duty cooling requirements and take the no cooling approach and let it cool between rounds. All in all, I think the idea has some very strong adavantages and would love to see someone else do it. The person who will eventually do it needs to be a guy with access to a lot of hydraulic equipment and have a good working knowledge of it.

I sold earth moving equipment for several years, and I was always thinking of ways to adapt that technology. I think after all that, it would be much more practical & efficient to use electric motors. I know, I love the sound of my V8 too. But it'd be alot less messier (is that a word?) and much easier.

Looking at splitter boxes & pumps, it wouldn't take too much to create something that could create a bit of wheel speed. I'm thinking of the splitter boxes out of crawler loaders (like Cat 953 or Liebherr 631). You could have joystick control and infinitely variable wheel speed. Problem is with those units - weight. Not sure of smaller units, but you guys oughta check pumps & boxes on smaller dozers.

But then I'm just a newbie.:flipoff2:

man, I swear I seen this frull hydro drive truck on the net some where that could balance it self on its back tires. I'll try and find it Sweet truck but I think the guy who owns it is a tree hugger

yup that be the one, spent a half hour looking for it but couldn't find it.

That was the vehicle I talking about this past weekend. I remember that vehicle very well especially since it was done locally (Seattle, WA). From the golden era of monster truck development, the late 1980's.

Hydraulics weigh a lot. They get hot. You can't build instantaneous wheel speed into anything with a hydraulic motor. If your pump fails or your filters fail it'll crater your whole system in no time. You can't "lock" a wheel that's in the air, but you may be able to divert the flow of oil from it to a wheel on the ground. Wheel motors stall even with the tightest clearances on a brand new machine... You can only force so much fluid around a motor even when it's jambed in mud or up against a rock before you blow a hose or something. Putting a hydro motor on the receiving end of a diff is something that's been toyed around with in construction and mining and generally works well. I will seriously have to remember to take my digi-cam to work. When your motor dies you got no go, and you can't drag anything with hydraulics without burning out the wheel motors. However, on Genie man lifts you can unlock the planetary hubs (take out the two 1/4 bolts, turn the dial 90 degrees, put the bolts back in) for seriously short distance flat towing. Seems to me that fabbing some spendy planetary and portal diffs would be better than goin hydro.

Good to know I'm not the only nut case around that thinks this is the way to go. My feeling is not to use so much heavy equipment parts as everyone I talk to wants to suggest, but to think along the lines of more light weight. For example I have a lawn mower that is hydraulic drive by way of 2 wheel mounted motors, a very small but powerful pump, and simple valve assy. With nothing more than a slight adjustment, this almost 1000 # mower will run 22 mph straight up a wall. I'm not suggesting the same parts are what's needed, this is just an example. It's only 25 hp. Still working out the bugs, but everytime I see a 4 wheeled crop sprayer go by the house at 40 mph with 4 feet of ground clearence I know damn well it's the wave of the future if we can just work out a few more bugs.

Exponential steering and power settings. Ya gotta love the thought.:smokin:

Originally posted by Old Syko
Good to know I'm not the only nut case around that thinks this is the way to go. My feeling is not to use so much heavy equipment parts as everyone I talk to wants to suggest, but to think along the lines of more light weight. For example I have a lawn mower that is hydraulic drive by way of 2 wheel mounted motors, a very small but powerful pump, and simple valve assy. With nothing more than a slight adjustment, this almost 1000 # mower will run 22 mph straight up a wall. I'm not suggesting the same parts are what's needed, this is just an example. It's only 25 hp. Still working out the bugs, but everytime I see a 4 wheeled crop sprayer go by the house at 40 mph with 4 feet of ground clearence I know damn well it's the wave of the future if we can just work out a few more bugs.

Exponential steering and power settings. Ya gotta love the thought.:smokin:

I have a mower like that also, it's called a Excel Hustler w/ a water cooled continental engine : ) , it gets awesome traction in any situtation, because the speed and direction of each wheel motor can be changed in a instant... A buggy with 4 Finger tip joysticks (or 2 sticks and 2 treadle pedals) could wiggle out of some pretty bad spots.
I thought the rules didn't allow this type of set-up, but I looked at ARCA's sight and didn't see anything that rules out indenpendant drives

We have those Gradall all terrain boom forklifts w\the 90* rear stering,I love that thing more than the 4 wheel steer

Here is a shot of that thing turning on a dime:D

http://www.gradall.com/material/model1.html

Originally posted by Jettech
We have those Gradall all terrain boom forklifts w\the 90* rear stering,I love that thing more than the 4 wheel steer

Here is a shot of that thing turning on a dime:D

http://www.gradall.com/material/model1.html

We usa the same type of setup at my work but its made by CAT...doesn;t have 90* either but does have 4-wheel sterring and about two feet of ground clearance...if I put it in 1st it will go where ever I want it to and it has a front locker too:D:D:D I have cause too much damage with that thing already, if my rig were to be like that I would be in trouble...

Well, this idea has crossed my mind a couple times. I used to work at a place in Redmond, WA called Genie Industries that built hydraulic man lifts. We made a model that was a 3 cylinder Kubota diesel that powered 4 hydraulic hubs.

The hoses and fittings that we used were very tempermental. Any bump to the hose or fitting would create a huge mess. No matter how many times you torqued it down to spec they'd always find a way to leak. Nothing like high pressure hot pink fluid all over you and your shop....hehe

The 4x4 model that we made did pretty well in the mud lot out back behind the plant. Well, that is until it got suctioned to the mud due to the flat underside of the unit. There was Zero suspension on them only turning front hubs. The tires were oversized and used to absorb the shocks and bumps.

So, what i'm trying to say is that to make each hub have its own suspension would be tricky. You would have to have some ultra flexitive hoses and make sure that there are all kinds of guards protecting the hose and fittings to work with the suspension flexing. Also, hydraulic systems are very heavy. The fluid weight alone is incredible.

Anyways, just had to chime in...

Later.

Ken S.

Originally posted by Daniel
close ... divide X 144 for real #'s people understand... very similar to



Nope, divide by 12 to get ft-lbs.

I think that hydrolics weigh too much for what you guys want. I have considered building an independant suspension that work along these lines however. If you had the diffs bolted to the back of the T-case and a driveshaft that routed the power to an ofset diff in the front, you could run the axle tubes to some 90 degree gear boxes on the end and bolt that whole assembly to the frame. Then run individual drive shafts down to boxes at the hubs that allowed 180 degrees of turning. The control arm setup would be complicated to allow that much turning and still control an individual box that was not conected to its counter part but anything is possible with enough time and effort.