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Ripsaw driveline

WaterH said:
As I said “I understand how it works” . I’m asking why they did it this way. Your post just goes on to explain what I already know.
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This sentence right here proves you have no concept of how it functions.


Now if you think about this, to turn right you must put some drag on the left side. That makes sense, but because of the spool, you must disconnect the inner and outer rotors.
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Cleetus posted another video where they got after it pretty good. It performed better than I expected. I would like to see it on some technical stuff, I wonder if it would pop the tracks in tight stuff.

 
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stjames151 said:
Can't see another way to use braking to help steering.
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simple little two speed transmission in each axle shaft, set up kinda like 1st and 2nd in a generic 3spd simpson gearset automatic
brake applied for high speed, release brake and it goes into 'low gear' on the side you want to steer toward
there's doubtless a better way to do it that doesn't have overrunning clutches (both for more positive steering action and so it doesn't just roll away on you)
 
Bebop said:
Have you ever tried that or are you speaking "in theory" ?

Because in real life, cutting brakes suck ass as traction devices.
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This. Any dozer that has steering brakes can go to hell. Why would you want to brake to turn. Losing power when you need it the most.
 
[486] said:
simple little two speed transmission in each axle shaft, set up kinda like 1st and 2nd in a generic 3spd simpson gearset automatic
brake applied for high speed, release brake and it goes into 'low gear' on the side you want to steer toward
there's doubtless a better way to do it that doesn't have overrunning clutches (both for more positive steering action and so it doesn't just roll away on you)
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was done in the next generation of tanks.

in between clutch/brake setups and epicyclic transmissions.
 
I’ve been intrigued by the ripsaw for years and have been watching all of these latest videos, since Heavy D bought it.

My take is that this unit was rode hard and put to bed wet for years and Cleetus is having to deal with that. I don’t see how worn brake pads and slightly misaligned calipers make it a POS? As for the 9” diff, there is additional reduction built into the drive system and from watching the videos, the tracks slip when it is super bound up. It’s not breaking and seems up to the task, imo.
 
Bebop said:
Have you ever tried that or are you speaking "in theory" ?

Because in real life, cutting brakes suck ass as traction devices.
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Not on a tracks, but I’ve stopped a spinning wheel on my tractor with good results. Also I remember one time getting an open diff van unstuck by applying brakes. (glare ice) Obviously, a spinning wheel or track is not giving you traction.

Anyways, not trying to start an argument. Just seems like a strange way to do it. One thing I can think of is there is a bias on one wheel with an open diff. So the idea of the inner brakes making it locked when straight might be the reason. Otherwise you might have to ride one brake a little all the time to go straight.
 
There are a ton of videos from the original designers of the ripsaw, Howe & Howe Technology. I remember seeing one where they explain the entire drive/brake system and how it works but your going to have to find it yourself but I sort of remember it being on the Howe & Howe TV show that was on briefly before they started getting into defense contract stuff. It was either Discovery or History channel......

 
WaterH said:
One thing I can think of is there is a bias on one wheel with an open diff. So the idea of the inner brakes making it locked when straight might be the reason. Otherwise you might have to ride one brake a little all the time to go straight.
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That's the whole problem.
 
[486] said:
simple little two speed transmission in each axle shaft, set up kinda like 1st and 2nd in a generic 3spd simpson gearset automatic
brake applied for high speed, release brake and it goes into 'low gear' on the side you want to steer toward
there's doubtless a better way to do it that doesn't have overrunning clutches (both for more positive steering action and so it doesn't just roll away on you)
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That's how the Cletrac controlled differential system developed for dozers (Oliver) worked. Used on the Sherman. Fairly simple, but has a single fixed turning radius. Apply brake, that side goes into lower gear, other side turns faster. Can turn a bigger radius by slipping the brakes, but no way to turn tighter.
000093-cletrac-controlled-differential-steering-system-figure-5-large.jpg


Double and triple differential systems are smoother but more complex. Most modern large tracked vehicles use these styles.
The Tiger used a double differential system, which is much smoother in turns than the clutch and brake on the Panzer III/IV or T34, but was prone to failures.


The Panther and Tiger II used a simplified double differential system that was subtractive rather than regenerative like the Tigers, and still used track brakes for tight turns.

 
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Maybach regenerative double differential system. Additional power input from the engine is clutched to the final drive, increasing speed of one track and slowing the other. Two speed steering input to change turning radius. Radius also depends on main transmission gear selected, i.e. difference in mainshaft and layshaft speeds. Can do a neutral turn. Put main trans in neutral, power from steering input turns one track forward, one reverse.

Modern double differential systems often use a hydrostatic drive for the steering input rather than a direct engine powered shaft.


Steering.jpg

Schematic with labels. Flipped from above image.
tiger steering-scr.gif


Triple differential as used in Chieftain. Steers with brakes rather than clutches. No additional power shaft input. Don't think it's capable of a neutral turn like the double diff system.
TN12 Chieftain.jpg
 
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would it be more simple to say it has normal brakes and turning is made by releasing drive from track using calibers/disk as clutch......
 
Bacho said:
If you look closely the inner rotors are actuated by a rotating collar that carries the pressure to calipers. Those are essentially a clutch and the outer rotors are a brake. I’m guessing that speed, brakes probably aren’t required to initiate a turn.

The ripsaw has always appeared to me pretty low quality. I have that same thought again now that they are appearing on YouTube.
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Low quality or not, it seems to work. It also looks like mostly “off the shelf” which I like. The machine I want to convert is all complicated “one off” hydraulic. Are you saying you know something about the “rotating collar” or you just making an observation?
 
WaterH said:
Low quality or not, it seems to work. It also looks like mostly “off the shelf” which I like. The machine I want to convert is all complicated “one off” hydraulic. Are you saying you know something about the “rotating collar” or you just making an observation?
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I saw brief mention of the coupler in one of the Cleetus videos, they didn't give a name but got me curious. I don't know ifit was built with an off the shelf assembly or a custom machined component, but after a little hunting I did find "high pressure rotary seals" seem to fit the application.

The link below has some capable of 3500PSI and 1200 feet per minute surface speed which should be plenty as long as they can handle brake fluid (though those inner "clutch" calipers probably don't generate much heat like the outer actual brakes do so you may be able to get away with another fluid if necessary. With one of these and a little machined housing you could make it happen without getting too complicated

High Pressure Seals | High Pressure Shaft Seals | American High Performance Seals
 
Ao
WaterH said:
Low quality or not, it seems to work. It also looks like mostly “off the shelf” which I like. The machine I want to convert is all complicated “one off” hydraulic. Are you saying you know something about the “rotating collar” or you just making an observation?
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I dont know anything about that specific one but I have seen them in other applications. For example the ARB locker uses a similar concept to pressurize the rotating assembly. I assume that part is custom made, which would not be difficult.

My take is they guys made a pretty cool machine years ago in the garage. It was crude then and is only a little less crude now. It works for blasting through mud puddles and the like. It doesn’t look remotely robust as a commercial piece of equipment would be built.
 
Bebop said:
Agreed 100%
Would be super cool to use something like a Focus RS rear diff with the integrated clutch packs.

main-qimg-f5eb524933b28e0a4011a4383b7be623-c.jpg
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I like it. You think that thing can handle 12 valve power? (Maybe 300hp and 600ft/lbs.)
 
bdkw1 said:
Looks like it's a spool? Clutches do everything?
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Yep and yep

WaterH said:
I like it. You think that thing can handle 12 valve power? (Maybe 300hp and 600ft/lbs.)
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No idea. The focus makes 350lbs/ft.
I don't think controlling the clutches is easy at all. I'm assuming some kind of a signal from an ECU is needed. At least that's how it works on the Focus.
 
Why not use two transmissions?

I had an old case 450. It used a high neutral low stick and forward reverse stick. Made for a nice set up to do sweeping turns and always having two tracks driving when you needed to turn and push.

Right track in low, left in high, forward gear and you turn right in a sweep. Drop the right track into neutral and do a half skid turn.
 
With the way electric motors and battery technology are coming along that would probably be a better option for driving a relatively lightweight tracked vehicle that is essentially for funzies. It would be better if the gas or diesel engine could generate enough juice to keep it going.
 
Bebop said:
Yep and yep


No idea. The focus makes 350lbs/ft.
I don't think controlling the clutches is easy at all. I'm assuming some kind of a signal from an ECU is needed. At least that's how it works on the Focus.
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judging from how it's built it looks like hydraulic pressure squeezes the clutch pack.
 
Dethmachinefab said:
Why not use two transmissions?

I had an old case 450. It used a high neutral low stick and forward reverse stick. Made for a nice set up to do sweeping turns and always having two tracks driving when you needed to turn and push.

Right track in low, left in high, forward gear and you turn right in a sweep. Drop the right track into neutral and do a half skid turn.
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That’s the first bulldozer my dad ever bought brand new. Case 450c. Awesome little dozer. We still have it and it still runs flawlessly to this day.

It also is one of the hardest dozers in the world to operate. Short tracks make for a rough finish unless your a god level dozer operator like my dad, and he can make that bitch sing.
 
The ripsaw looks to be an overhyped pile of shit. The clutches/brakes are a joke. 80 year old caterpillar technology is far superior to what ripsaw is doing. The only thing complicated is controlling the calipers. Wet brakes/clutches would of been superior but probably too complicated for them.
 
Tractor Monger said:
The ripsaw looks to be an overhyped pile of shit. The clutches/brakes are a joke. 80 year old caterpillar technology is far superior to what ripsaw is doing. The only thing complicated is controlling the calipers. Wet brakes/clutches would of been superior but probably too complicated for them.
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You do realize that the 1st gen Ripsaw like Cleetus has hits 60 MPH, and the 2nd gen goes over 70, right?

And controllably? Here's the 1500HP version thrashing:



I've never driven anything tracked that goes faster than a moped, but I'm pretty sure cost wasn't the only reason for their design choices. Overhyped, yeah - but it seems to be a good platform as an all-terrain fuck-around toy.

Everything I've read and watched about them indicates they hold up pretty well (as a toy, not a tank). Good enough that Textron bought the platform and business from Howe & Howe, no idea what improvements they've made since then.
 
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