Amphibious Kettenkrad

[Bw6]

RD, Hey thanks, it's different. I was debating whether to use hyd. or mech. to drive the front wheel, as it turns out I can do it mechanically easier. But with all the traction from those 15" tracks and 30" tires, I may not need to drive the front. Anyways that decision is still a ways off. What really made me smile was without thinking I really gave it some throttle from a dead stop and the front end did a wheelie!

[Rock Doctor]

Very interesting project, I like it.
There was a comment earlier about using a Hyd Motor as a pump. Depending on the type, yes you can interchange some of them. I'm pretty rusty on my Hydraulics, but I'm sure it can be done.


RD

[Bw6]

Amphibious Kettenkrad Project (Testing Half Tracks)

Well here is an update to this project. I completed the tracks, decided to see how a set of "Half Tracks" would perform. Was pleasantly surprised! Looks like there is plenty of traction, no slipage that I could detect. Tire were under inflated, which caused the steel guides to just touch one another as they wrap around the tire circumference, guides should have been about 1/2" shorter.

Also I need to remove "one pitch" from the right track it is just too loose and is hitting the top of the fender in one spot periodically.

Another thing is the front "cruiser tire" is really useless in the snow, it will be replaced with an aggressive knobby as well. Next job is to install the Wilwood "steering brake master cylinders", stayed tuned.

Here is a short video of the first run with "Half Tracks".

[Bw6]

going pretty good BW6.is that machine at cams buisness?if so i could drive down one saturday at the end of march- begining of april at take a gander.

cheers.

Yes it's in my large trailer, drop by.

[plott hound]

going pretty good BW6.is that machine at cams buisness?if so i could drive down one saturday at the end of march- begining of april at take a gander.

cheers.

[Bw6]

Im not sure if it would work but wouldnt a hydraulic motor on the front wheel hooked to a hydraulic motor on the rear wheel work? The mechanical driven rear would use the motor as a pump to run the front? Not sure but maybe something to look into. You could use either setup of a wheel motor or chain/sprocket setup to hydro motor)

Hi Larry, I tell you what I had in mind for the hydraulic circuit. I probably use a power steering pump (vane pump), I've checked these out and some them, especially the big diesel pickup's have a decent P/S pump in them. A good one will pump about 4 gpm @ 1,000 to 1500 psi., you can get the ones that use a remote tank and just swap the tank out for something that has a little more volume. As we know these P/S pumps are almost bulletproof and low cost. I would drive the pump from the other side of the crankshaft on my engine, the same way some of the external alternator kits mount. Another way is I've seen one of the members using a v-belt pulley (sheave) on the clutch side as well for an external alternator, either way would work.

I've already picked out a nice small hydraulic motor that would mount in the area of the brake calipers, picking up the holes for a bracket that would house the hyd. motor. For the other sprocket I would remove one of the dual rotors for the disc brakes, and use the bolt pattern to pickup the sprocket, then a short loop of chain, up to the motor spocket, and that should do it. I would pick a sprocket ratio that would come close to the rpm. I need to match to the rear tire. This is where a mech. tach, and a pressure compensated flow control valve would do the fine rpm tuning. This method should get it pretty close. I would just hard plumb it with some small flex lines. For forward and reverse I would use a 12v directional control valve with an open motor spool, with a detent position for float this will allow me to coast, as I would probably only engage the front wheel when needed. I'm using the solenoid type instead of the manual type because I'm using a 12v linear actuator to shift from forward to reverse on the transaxle, instead of running long cables to the back. So whenever I would shift the transaxle into forward or reverse the 12v solenoid would shift the spool in the DCV.

BW6. Very interesting link. I've seen an AWD mountain bike before, but never the internals. I'm supprised at the gap the front is underdriven by, but the principal is the same as some of the 1/8 on-Road R/Cs I used to race, though the underdriven gap was minimal.
If not having power to the front wheel in reverse was no issue I think that would be the perfect setup. Not the most simple, but it looks like you've already made more complex parts for this hobby before.

6x6, thanks again for your interest. Check my response to Larry for the hydraulic details, which is simplier I think that going mechanically (I think).

holy moly BW6,thats a great looking creation.cant wait to see it in action,personaly that is.

Hey Plott, howsit going? Yeah just waiting for spring, to get back on this projict. I just got back from the waterjet guys with my grousers for the tracks. Drop by when you get a chance.

[plott hound]

holy moly BW6,thats a great looking creation.cant wait to see it in action,personaly that is.

[Stonewall]

[QUOTE=LarryW;86192]Im not sure if it would work but wouldnt a hydraulic motor on the front wheel hooked to a hydraulic motor on the rear wheel work? The mechanical driven rear would use the motor as a pump to run the front?[QUOTE]

That sounds good, but I'm pretty sure that you can't use a motor as a pump. You could probably do that with a real pump and the proper sprocket ratios, although I believe you'd still have to have a fluid tank (unless you could fill the pump, motor and both hoses without getting ANY air in them).

Edit: I have issues with quotes for some reason...

[6X6]

BW6. Very interesting link. I've seen an AWD mountain bike before, but never the internals. I'm supprised at the gap the front is underdriven by, but the principal is the same as some of the 1/8 on-Road R/Cs I used to race, though the underdriven gap was minimal.
If not having power to the front wheel in reverse was no issue I think that would be the perfect setup. Not the most simple, but it looks like you've already made more complex parts for this hobby before.

[LarryW]

Im not sure if it would work but wouldnt a hydraulic motor on the front wheel hooked to a hydraulic motor on the rear wheel work? The mechanical driven rear would use the motor as a pump to run the front? Not sure but maybe something to look into. You could use either setup of a wheel motor or chain/sprocket setup to hydro motor)

[Bw6]

If you go with hydraulicaly powering the front wheel, you might try to research some of the older John Deere 4020 series tractors. These tractors were available with a hydraulic powered front wheel assist (the rear wheels were still mechanically powered). Tractors with this system are rare, but you might be able to find out how they got the hydraulic fronts in sync with the mechanical rears.

Interesting, thanks, will check them out.

[Stonewall]

If you go with hydraulicaly powering the front wheel, you might try to research some of the older John Deere 4020 series tractors. These tractors were available with a hydraulic powered front wheel assist (the rear wheels were still mechanically powered). Tractors with this system are rare, but you might be able to find out how they got the hydraulic fronts in sync with the mechanical rears.

[Bw6]

Personally, I hope it works well without having to drive the front wheel, of course if you gear/shaft/chain drive it there's the part of getting gear ratio/tire circumference to match the rear driveline, and if you change tires to a different size front or rear..... I'm NOT that well versed in hydraulic drive to know how close it would have to be, I figure it has some give, not sure how much.
Of course, just going by the original Kett, I personally like the look of a narrow M.C. tire.
Keeping an eye on this one for sure.

6x6, Were singing from the same songsheet, driving the front wheel is a challenge either hyd/mech. The front wheel has to "lead" a little. If I went this way I would keep the M/C tire, just change it to a motocross or enduro type. Hydraulically I would need to use a "pressure compensated flow control valve" and a mech. tach to match speeds, that along with a solenoid operated directional control valve for F/Rev. With this setup I would only engage the front wheel drive whenever I needed a little help getting out of a hole etc., otherwise the DCV would have a "float spool" position that would allow the front wheel to coast. Mechanically it would be selecting a sprocket ratio that would match. Right now I know of 3 patents covering this setup. Here are two of the links, very interesting reading.Christini All Wheel Drive Motorcycles
How it all started - Öhlins

[6X6]

Personally, I hope it works well without having to drive the front wheel, of course if you gear/shaft/chain drive it there's the part of getting gear ratio/tire circumference to match the rear driveline, and if you change tires to a different size front or rear..... I'm NOT that well versed in hydraulic drive to know how close it would have to be, I figure it has some give, not sure how much.
Of course, just going by the original Kett, I personally like the look of a narrow M.C. tire.
Keeping an eye on this one for sure.

[Bw6]

Won't having 2 wheels on angled forks like that be hard to steer? You might try 1 wheel mechanically driven with something similar to a Rokon.

Stonewall, Yes you are absolutely right, because of the rake angle it was hard to steer. It would be easier if I changed the tire selection and went to narrow m/c tires, and moved them in. What I found was when I turned to lock the outside tire would lift off the ground so only one tire was driving. That meant that I would have to engage the locking diff. all the time. Also the diff. mounting brackets needed to be very rigid so that when one fork was compressed the other would have to move in unison. Not one of my better designs, lol. It's amazing how one thing leads to another, because of the hard steering I was going to design a power assist...blah, blah, blah. But after critiquing the thing, I decided that it would be easier to just drive the single wheel either hydraulically or mechanically, similar to the Rokon. But hopefully I won't need it. I'm hoping that the tracks will give me enough traction that the front wheel won't impede my progress. Thanks for the comments Stonewall!