Why wouldn't this work?

[JohnF]

Ah, those are big. Don't remember those in your videos...
Yeah, those will hurt. They probably win too. Unless they shoot em.

Chicken, if you don't stand up to him/her he/she can't take you serious.

So, was just looking at tire. For me I was thinking something like the 22x11x8 turf tamer, about $70. And I imagine I would have to make the beadlock wheels.

[Rock Doctor]

....this would then leave the two center axles disconnected, I would then chain them together and hack saw the last 5" off of each axle and then weld a short 3" arm with a new spindle and freewheeling hub welded to each axle with the front one pointing down and forward at a 45 degree angle and the rear one pointed down and back at a 45 degree angle (when one moved up the other would move down and the newer 8x8 frames with 27" axle spacing would allow this to work with the factory 24" tires)....this would give a simple and effective walking beam type motion on the two center wheels and increase ground clearance an inch and a half

RD, I'm not able to easily post pics from my phone, but if you are serious about building a custom tracked 8 wheeler and would like to see what I'm building I would be happy to email you some pictures and start to get some feedback and suggestions from a few more of the forum members.

I'm enjoying all your creative ideas.

Tim

This ^ Is Freakin BRILLIANT, I love this idea

Tim, I would love to jump into a project something like this, but at the moment I have 3 young daughters that I would rather spend my free time with. I wish you and I had bumped into each other 15yrs ago. Back then I had more free time than I knew what to do with. I like this even better than the idea of running Track Tuners on the center 2 axles with 24" Tires, and 22" tires on the front and back axles of my Conquest.

RD

[Rock Doctor]

It would be cool if you would go poke a driver in the chest and tell him he can't and watch him give it a go. The muskeg might stop him but I don't think you have any trees big enough to stop him.

LOL, well, these might not stop him, or hurt the machine, but I bet they slow him down a bit
[IMG]
A little sidetrack here, but back on topic now


Hehe... I guess we all got gears spinning on this. I imagined a track just like the Adair track that ride the outside diameter of the tire. The cogs are proud of this but don't extend beyond the grouser so the gear ratio should be pretty much what an track is now.

This ^ is sounding like what I'm thinking

RD, every time I write a long answer it gets lost to the signoff demons. The point I was trying to make was all the force would be applied to the outer idler bearing, flange or frame as a potential failure point, the counter rotation of the chains reduces some of the force applied to the bearing and supports, by removing it, it multiplies the force applied at that point. A bearing at the inner frame rail may help this.

I agree, this could be a failure point, but the inner bearing will help.

Where can I find an Abrams Driver that I could poke in the chest? Keeping in mind that he has to be slow enough on his feet so I have a chance to get away

RD

[JohnF]

Tim, The center axle idea of your's sounds cool.

I don't understand driving the rear axle instead of the front? Is it so that you have ready chain adjusters? With a sprocket I don't think the track is going to care front or back and I think there is advantage to the shorter run.

Unless you aren't using a sprocket but relying on friction and driving both the front and back tires. This really wouldn't remove chain windup. And you no long have limp home mode; I don't know how important that one is but it has been mentioned.

So, last night I gave it a little more thought. The slop in the sprocket/belt cog interface (the 2 foot problem) makes stopping on a slope exciting, changing fwd/rev a little clunky, AND it will affect turning response time. I suppose I could learn to live with the first two but suspect I would really hate the last one. I think we need to design this so that the sprocket fully captures the belt (track) cogs.

I also got to thinking about tire guides. If I put the sprocket front and back with the back still an idler then I don't need tire guides since the track is fully captured. This would create two problems. In my original design I used the tire pressure of the back tire to adjust track tension. This new design needs something else that could be a little more tricky. Worse, this new design requires the front and back sprocket to be synchronized which requires choosing a cog/sprocket pitch dependent on exact axle spacing. This means you could not make a tracking system somewhat generically usable across varying machine axle spacing.

So far I'm sticking with one sprocket and tire guides.

And about the sprocket build. Generically I've described this as a trapped tire. Okay, what I see is a tire on a dual beadlock wheel. It is important that the sprocket ends up diameter stable and, from playing with air pressure and my tires, what I have isn't anywhere close to diameter stable. So I added belting external to the tire to accomplish this. It may be that there is a tire that is already diameter stable in the air pressure/suspension range that we need. If there is then we could bolt the sprocket cogs right to the tire, add an internal protective surface, and use a tube or balls for air.

If we must rely on the sleeve for diameter stability we can still bolt this to the tire at one point to combat the tire from spinning inside the sleeve and use the same tube/ball air system.

And one more thing...

RD mentioned spinning the tire as a safe point of failure. I go to thinking about this too. Let's imagine that the track becomes totally immovable and that the engine has the grunt and that everything is break proof. What would happen? I imagine that the torque will twist the tire until the diameter shrinks enough that the sprocket pulls out of the track and skips a cog. Probably loud and scary. A big detent torque limiter. We could maybe incorporate this but I think with the machines we are talking about that the CVT will check out and you will squeal a belt, also a torque limiter.

[mightymaxIV]

They run these types of machines all the time in the Florida Glades. Last one I saw had a rear end from a 1947 snow cat. The tracks were wide and custom made from steel. The tracks were driven off the rear wheels and the owner had hand made a custom gear that fit right into the tracks (similar to the system used on a tank) for an absolute positive drive system with torsion track tighteners’. The drive train was a 460 cubic inch Ford engine with an automatic transmission. The machine had over 40 inches of ground clearance and the pilot and passengers sat on a flat deck that was positioned above the engine and transmission. The whole machine sat about 9 feet tall. I talked with the owner and took several pictures with my cell phone that were lost when my phone died. These machines are quite common in southern Florida and each one is custom made. The owner told me they rarely get stuck but when they do only another tracked machine can pull them out.

[Obsessed]

RD...I think you guys are all on to a great idea of a more efficient, lighter weight, and lower maintaince tracked only 8 wheeler.

I have played around with all of these ideas myself and my version of what you are describing would start out with a light weight and inexpensive 8x8 frontier....I would then slightly reconfigure the drive train to drive the rear axle off of the idler shaft (instead of the second axle back) which would run a longer chain and utilize the two rear chain adjusters.....this would then leave the two center axles disconnected, I would then chain them together and hack saw the last 5" off of each axle and then weld a short 3" arm with a new spindle and freewheeling hub welded to each axle with the front one pointing down and forward at a 45 degree angle and the rear one pointed down and back at a 45 degree angle (when one moved up the other would move down and the newer 8x8 frames with 27" axle spacing would allow this to work with the factory 24" tires)....this would give a simple and effective walking beam type motion on the two center wheels and increase ground clearance an inch and a half... It would also use all origional drive components, less 4 sprockets and only sacrifice the modification of the 4 center axles...no permant damage to the machine. I have ideas that would take this design even farther for improved performance. In fact, I have taken this concept so far over the past two years that it is now turned into a custom built machine (actually a couple different models) that are currently under build as prototypes for testing purposes with the intention to someday be in full production..

RD, I'm not able to easily post pics from my phone, but if you are serious about building a custom tracked 8 wheeler and would like to see what I'm building I would be happy to email you some pictures and start to get some feedback and suggestions from a few more of the forum members.

I'm enjoying all your creative ideas.

Tim

[ARGOJIM]

RD, every time I write a long answer it gets lost to the signoff demons. The point I was trying to make was all the force would be applied to the outer idler bearing, flange or frame as a potential failure point, the counter rotation of the chains reduces some of the force applied to the bearing and supports, by removing it, it multiplies the force applied at that point. A bearing at the inner frame rail may help this.

[JohnF]

... So, if you crest a hill and stop, would you not only slide forward a couple inches at most, before the back side of the tire Cogs make contact with the "Next" Track Grouser?

Yep, whatever the space is. I just used the 2 foot example to make it obvious. It would also slip when you changed fwd/rev. Ideally we would trap the grouser just like the snowcat does which could be a balance act between way too many grousers (cost, complexity) and/or sprocket cog flexibility/clearing issues.

The Abrams are , but I can't pictue them making it into my cabin...

It would be cool if you would go poke a driver in the chest and tell him he can't and watch him give it a go. The muskeg might stop him but I don't think you have any trees big enough to stop him.

...The only concern about using a sprocket that crossed my mind is if you "geared-down" the output of your drive sprocket so that your engine torque is multiplied and more than the axles and bearing cages (if you had them) and frame could handle...

Hehe... I guess we all got gears spinning on this. I imagined a track just like the Adair track that ride the outside diameter of the tire. The cogs are proud of this but don't extend beyond the grouser so the gear ratio should be pretty much what an track is now.

[Buzz]

[QUOTE=Rock Doctor;139556]Gotta love how great minds think alike

OK, so lets leave all the tires on, so suspension will not be effected any more than any other track system. For the sake of discussion, lets say I have a 25" "Aquatorque Type" tire on the front of my machine, where the lugs just happen too match the Pitch of this mythical Track, and I have 3- 24" Frontier Tires for the other 3 axles........ I provide power to the front tire only, with the chains to the back 3 axles OFF.

The torque to the front axle should not be any greater than the force in the Trans Output Shafts, or the Idler Shaft though, right? If these components can take it, should't an axle take it? The Driving Tire on the front should spin on the rim before you twist off an axle...... Which brings up another possible issue...
There can be no "Chain Windeup Issues", if there are no chains, all back 3 sets of tires would be free to spin at any speed, so less worries about tire diameter.

John, would using a Tire as the Sprocket, as mentioned above, address your Sprocket suspension Issue?

Buzz,
Help me visualize, now that I've added more detail, do you still see "More chance of breaking, and less give" somewhere? Bouyancy should remain the same. Ability to run on just tires would definatly be effected, but what if you had your chains, and could put them on if the need arises? We would still have a 25" tire mached with 24" tires, but for a "Limp Home" run, it would be OK.


Am I getting to "Out There" yet, lol



yeah, you're definitely on to something. Keeping all your tires would be a huge advantage since you are amphibious unlike some track machines. Tires could scrub or skid to handle the wind-up okay. I've always thought it's cool that you're still in pretty good shape even if your tracks break or fail or something like that. Shoot, you're still an 8-wheeler which isn't bad at all. The only concern about using a sprocket that crossed my mind is if you "geared-down" the output of your drive sprocket so that your engine torque is multiplied and more than the axles and bearing cages (if you had them) and frame could handle. Usually, your engine bogs first, but with ultra-low gearing...who knows. And yeah, bringing your chains seems like a great idea too. Finding a tire that would engage like a sprocket would be great...if possible.
If not, I'm trying to picture the best set-up to maintain the bouyancy of the drive axle without getting in the way of a standard drive sprocket. I guess once you figured out the sprocket diameter that's needed, you could come up with a design plan...seems like floatation tires would need to be smaller than the sprocket. I have a feeling the sprocket would probably be smallish so that might be tough to accomplish...maybe just adding more floatation to the front of the machine (like a large boat fender that's removeable) would be the best. It would be cool if you could replace a bolt-on sprocket with a bolt-on wheel/tire if needed. In fact, if the body diameter (not teeth) of the sprocket was the same as the tires, you could interchange them without having to change the track length. And, the sprocket teeth would stick up higher than the tire tread. You might be able to sandwich a wheel/tire between 2 drive sprockets. Driving the "center" of the track with a single sprocket or both edges of the track with 2 sprockets I think makes the most sense (I think). I'm kind of "guessing" on all of this. I'm probably out there!

[Rock Doctor]

John, I was thinking something more like 4" spacing between Track Grousers, and 2" wide Cogs on the tires (Apropriatly spaced so that the tire Cogs would mesh with the Grouser Pitch. So, if you crest a hill and stop, would you not only slide forward a couple inches at most, before the back side of the tire Cogs make contact with the "Next" Track Grouser?

As for the Track Suspension, lol, I was thinking "any other track system" on an Argo :-)
The Abrams are , but I can't pictue them making it into my cabin........... I could be wrong on that though, I've no experience with driving one through Muskeg

RD

[JohnF]

Something else to to think about. Imagine that the pitch of this system is 2 feet - cogs on your tire and grousers - and your cogs on the tires or track are 2 inches. You will engage only one side of the cogs at a time and it could be a little unsettling if you crest a slope, stop, and the machine slides about 2 feet before it stops. A snowcat sprocket wedges the grousers and we might want to do the same.

... so suspension will not be effected any more than any other track system.

Just had to chuckle. Have you seen the suspension on the Abrams? Watch that guy going 70+ mph across fields and it is just too cool. Of course it has a little different sprung/unsprung dynamic going on... If we want to get into this realm even a little I think we are going to need to get Whipper involved.

[Rock Doctor]

buy yourself a bombardier "bombi".all the work is done for you.

LOL, I used to run one of those when I was 14yrs old, building Mining Roads. They are heavy and a PITA to work on. The one we had was a 4 speed with manual Trans....... Maybe it was 3 speed....... Anyway, good luck getting it into top gear without slowing down to the point of having to actually Backshift.
No, I want something smaller and lighter AND, something that could be made out of an older Conquest Parts Machine, lol.
The thought is rather similar to a Snowcat though, My buddy has about 5 of them, and a few Haglunds too, but I've never really had a chance to scope them out too much.

You lost me Jim, sorry. Equal pull on Jackshafts....
On a normal Argo drive system, you have the Idler Chain pulling up, Front Chain Pulling forwrd, and second axle chain pulling backwards on the Jack Shaft. But on the Trans Output shaft, there is only pull in one direction, same goes for the front axle......

RD

[JohnF]

Yeah, I guess I should have mentioned it but that's why I used the tire as the sprocket. I imagine the designers of the machine imagining that it would take torsional loads one axle at a time, imagine going over a log, and sizing all of the parts so a single axle could do it. I would also imagine we would all have stories and warnings of not loading only a single axle or face replacing it. But if it were a real issue we will only have to beef up one set of axles.

Also, I deal with the spinning tire on the wheel issue (forgot about that) and imagine this wheel sleeve system using a tire on a real beadlock wheel. I don't think I want it slip and like a tractor expect all slipping to happen between the track and ground. Note, with chains and tires and tracks (current system) I think the wheel being able to slip is important and necessary.

Oh, and a to the tires - the bogies can be any tire so soft ride would be where it is at. Also, size does not matter (really) so you could use anything reasonable (keep the track tight, etc).

EDIT: It just occurred to me that you might mean your tire as a sprocket (aquatorgue(ish)) vs my tire in a sleeve. Yes to that too. I would think a rubber only cog on a sprocket may have wear issues. The snowcat sprockets are rubber on steel. I was imagining my sleeve using UHMW or aluminum cogs to match the grouser depth. Worth an experiment - especially since all the parts exist.

[ARGOJIM]

Sounds as if you boys are heading towards a Snowcat. As far as the chain drive it seems all manufacturers either have equal pull on the jack shafts or center axle, I'm no engineer but seems equal opposing force issue at the point of transfer.

[plott hound]

buy yourself a bombardier "bombi".all the work is done for you.