By Arlie on Unrecorded Date: Edit

I have seen alot of talk concerning hydraulic motor powered ATVs, but what about the possibilities of air motor power? The principle would be similiar to the hydraulic motor. A hydraulic drive uses an engine to turn a hydraulic pump which pumps the fluid through the drive motors. An air motor powered ATV could use an engine to drive an air compressor which would store the compressed air into onboard tanks which would then be fed through regulators to the air motors which drive the wheels. In principle, this would allow several things. 1. The stored compressed air in the tanks would act as a buffer, allowing the engine to run at more of a constant speed regardless of vehicle speed. (excess pressure would be bled off). A hydraulic vehicle would not have this "buffering" storage capability. 2. The air storage tanks could act as an inflation source for floats for amphibious use. 3. A broken air line at 100 or 150 PSI would be nowhere as disasterous as a broken hydraulic line at 2000 PSI spewing hot hydraulic fluid everywhere. A "sturdy" compressed air tank or line at only 100 or 200 PSI would only leak if punctured, not explode. 4. An auxiliary air motor driven from the storage tank could power a propeller for amphibious use. The main question would be: Just how many cubic feet per minute of air could be obtained from a 25 horse engine driving the air compressor pump? How many CFM would be required for each drive motor(s). I anty up the above comments as food for thought.

By BILL on Unrecorded Date: Edit

Arlie,

First of all, it's one for the engineers to ponder. It sounds great, but I'm sure that there are a lot of problems with using air instead of hydraulic fluid.

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Cons-

1. Is it strong enough to properly power a vehicle?

2. Size and weight of the compressor needed to do the job.

3. Noise factor! Compressor and motors would be very loud.
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Pros-

1. The part I like the best is having different valves for different uses-
One valve for all wheel drive
One valve for 2 wheel drive
One valve for the propeller or propellerS.

2. No need for a second cooling system (hydraulic vs. air). Also, you could use the bleed off by hosing it directly over to the engine for extra air cooling efficiency.

3. You would also no longer be a skid steer. It would work like a Triton Preditor - full time forward and reverse and left and right are independent from each other.
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I'm sure that the biggest problems with this kind of power source would be POWER and NOISE.

Just helping you throw a few thoughts around.

BILL

By kush on Unrecorded Date: Edit

I think the weight of the compressor, motor to run it & the tanks needed might be excessive.

Wouldn't you need a heck of a lot of CFM?

By Arlie on Unrecorded Date: Edit

Yes, the CFM requirements would be pretty high. I do not have a lot of specs on air motors. I know that they are not as common as hydraulic motors but they are used in many commercial applications. Does anyone know of any industrial catalogs that would list specs for air motors? I know that I saw a listing once for some 5 HP air motors. Don't remember the CFM requirements. The dream machine would contain a 5 HP air motor on each of 6 wheels, all being driven by a common air tank driven by a 25 HP (or larger?) powered compressor. Sounds like a tall order, but nothing comes easy. If the CFM requirements could be achieved, it would seem that an air system would be less complex than a hydraulic one.

By Homer the Bold on Unrecorded Date: Edit

The biggest problem with using air is the compressabilty of air. What will happen is you will open the air valves to engage the motors and the preasuure will build until it overcomes the resistances of the road wheels. Once the inertia has been overcome the compressed air will continue to expand until it equalizes. You get a thrill ride with a phenomel launch and zero control. One rule of fliud power is if you need rapid acceleration, use air, if you need control, use hydraulics.

By E L McKenney on Unrecorded Date: Edit

We use small air motors to power the hose reels on one of our welding trucks, our main problem is that they sit outside and freeze up if not used every day. and yes we have an oiler on them.