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Brake Steer vs Hydro - school me

Nikson

Bronze Member
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as many might know, I've been restoring the Frandee for past few month, which got me thinking to build a cat from scratch.

So the whole open differential 4x4 car design that Frandee used, is that efficient system or does not work wholesomely in the real world?!

In my times of use, I've found it to be doing the job, may be not efficiently well, but considering its years of design (40-50s) - its alright.

So question arises, if one to put a strong enough engine to power a 4x4 open differential drive train with say oversized disk brakes - will it work efficiently smooth on steering or do I forget it and try on building my own hydrodriven system?

p.s. how I'm seeing it

5.9L i6 cummins / 6.0 LS V8
Auto tranny with manual valve body (to select gear manually as needed)
NP205 gear driven transfer case (divorced)
14bolt rear ends to fit the 4x4 open diff system
Biggest disk brake kit available on the market on all 4 drive wheels/sprockets
sprocket driven track system
36wide tracks similar to Spryte's drop-center design

Goal/Dream:

Run a plow to level those offcamber/tank traps
Tow up to 15000lbs max
Cab that can carry comfy 12 passengers
2000lbs cargo capacity (on top of passengers)
Gross weight of the cat under 8000lbs
Oh, forgot to mention - on a good day / straight away, I want it to be able to do 35mph (and yes, I've thought about the right suspension)

AM i cRaZy?!

p.s.s. Frandee leading the pack...
 

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300 H and H

Bronze Member
GOLD Site Supporter
Interesting project for sure,
.

Have to wonder if you get the ground pressure down to acceptable snow cat levels, if the tracks will not be so wide as to pose a problem trailering the machine.

Big groomers have these types of credentials, and have to be de tracked to be moved. But they are Hydro machines and are heavy.. Hope you find out it can be done with reasonable width tracks.

Regards, Kirk
 
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Nikson

Bronze Member
GOLD Site Supporter
How about an air cooled diesel driving hydraulics?


Not sure, hydro stuff is all new to me, as my experience is limited to brakesteer kinda stuff...



Hoping for some insight to see whats up...
 

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
Nixon the planetary steering differentials aren't really brake steer, say like the fandee or a crawler dozer , when you apply pressure to the steering band it slows one track down with a set of planetary gears and speeds the other side up through the differential gears thereby applying power to both tracks at different speeds for steering. in brake steering or clutch and brake steering you remove power from one track applying a brake and than driving with one track only. The planetary steering used in thiokols and bombardier products are much more efficient in soft terrain, but is limited to a fixed ratio also the differential functions as an open differential when no brakes are applied which is the reason for the machines wanting to drift one way or another as the friction changes on the ground. snow tracs have one advantage in that the varriator belt ties both sides together at all times. hydrostatic drive in simple terms like a bobcat can vary the speed between the tracks and still maintain power to both but I find usually they just slow down one track because they always run wide open. some of the newer stuff with electronic controlled hydro static systems will operate pretty impressively but are complex and expensive also at best you are going to get 70% efficiency, meaning you will need more hp to do the same job with hydrostatic drive.
 

Nikson

Bronze Member
GOLD Site Supporter
Nixon the planetary steering differentials aren't really brake steer, say like the fandee or a crawler dozer , when you apply pressure to the ... complex and expensive also at best you are going to get 70% efficiency, meaning you will need more hp to do the same job with hydrostatic drive.


This is a great conversation...



so in your opinion, running a strong engine and open differential system for brake steer like Frandee, is that going to work out or not really?

I'm having a hard time thinking that brake steer in general weather its drum/disk or OC12 brake bands - are similar or not really?!
 

cloudcap

Member
GOLD Site Supporter
It will probably make your head hurt (I know it did mine...), but check out the pretty colored diagrams at Tracked Vehicle Steering. I believe the brake-steer in Imps and Sprytes is what the author would call 'Controlled Differential Steering'.

Ron
 

Cidertom

Chionophile
GOLD Site Supporter
For me the one outstanding thing is effective power AKA efficiency. Don mentioned 70%. I've seen as low as 60, high 50's% on hydro power driven equipment. Either way that's a lot of heat to be thrown away. Throwing away that much heat has its own issues.



I've sketched some 'rube goldberg" ways of having an expanding track system for road trailer then expanding to snow wide track. None of which would be particularly viable given today's technology. (think "transformer cartoon series)


Good luck and I want a ride when you build it.
 

rockhead

Member
cidertom, skip the expanding tracks and just move to British Columbia. Sure we have lots wideload restrictions like civilized places, but bales of hay or straw are wildly exempted.
The way I see it, all I need is four bales that I can attach to the corners of the tracks and I'm GOLD !:laugh3:
I test drove a homebrew cat that was a profound disappointment, hydrostatic, it was billed as 'light and fast' not sure about the weight but it was sadly slow. The builder later said the 42HP motor was not revved up ( no tach ) but wow, hydraulics course I took alleged that you could stall your load without stalling the engine but this poor thing had so much more pump than engine that it would die if you didn't creep it up hill.
 

Cidertom

Chionophile
GOLD Site Supporter
H'mm a KT7 is basically the same as a ton bale. add a few 90 pounders along each side... Get someone to reproduce this as a vinyl print cover and stealth trac. drape it over the cat and off you go. In my case it would probably be off to the impound yard, failure to have the hay certified "weed free". Transporting weed across state lines is still frowned on.:smile:
 
On the 2800lb Frog the economical brake diff steer has its drawbacks with power efficiency. Other issues include the brakes getting wet from freeze/thaw ice or fording in the swamp. The vehicle wanders quite a bit as well at high speeds (as pointed out above).

With the speeds you're looking for, I'm not sure a hydrostat would be the best option.

There were a couple of clutch/brake units I saw when I was planning my next project, the units themselves were inexpensive, the problem was most were in Russia so shipping costs were high for LCL:

GAZ-71 : Modular spur/bullgear aluminum case final drives, multi-plate clutches with band brakes, made for 12000lb vehicle
GTT : Modular planetary final drives, planetary type clutch with band brakes, made for 18000lb vehicle
MT-LB : Modular planetary final drives, planetary type clutch with band brakes, integral 5 speed transmission, made for 28000lb vehicle

In the end I decided on using a locally sourced Acura MDX rear axle and attaching inboard disk brakes to it. My only concern is I need to build or find some kind of final drive to prevent the clutch plates from burning out
honda-sh-awd-xxx.jpg


I guess I would try and balance performance needs to your intended budget. It would suck to have an awesome chassis getting bogged down by its steering system :(

[RANT OVER]
 

MNoutdoors RIP

Gone But Not Forgotten
GOLD Site Supporter
Nik, when I get some time I will elaborate on this.

But trying to get 35mph from a hydro system is not going to be a reality
Best I know of currently is 20-22 with 400hp.excluding the Abrams tank which
Really doesn’t count it’s more mechanical with hydro steering and a lot more weight and HP

You list 15,000 pound towing capacity? Do you mean 1500?

https://m.youtube.com/watch?time_continue=1&v=_z3n6VOk-Ls
 
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turbinator62

Active member
Site Supporter
SUPER Site Supporter
Hi Nik. I knew you would be building a SUPERCAT one of these days.
Do you remember the "Porterbuilt" cat at the 2014 Leavenworth Jamboree? It was hydrostatic. As I remember it was having some issues. It was on Craig's list a few months ago. I am assuming he got the problems sorted out.
A hydrostatic drive system could get really complicated with variable displacement pumps, motors control valves and servos etc. You can indeed stop one track and turn on a dime, or even run one forward and one backward. You can also walk it out of the tracks if not careful. I agree with the other guys that they are extremely inefficient. You could potentially have a lighter vehicle, but much more expensive and complex. I think your best bet would be to build The NIKSON SUPERCAT around a C-12 rear end and stay with planetary differential steering. Build the body frame and skin from aluminum to save weight with that new TIG welder you want to buy. It probably wouldn't be too hard to use 2 vacuum assisted power brake master cylinders for the steering to reduce the force required to turn.
I used to do a lot of work on Hydraulic pump-motor systems and they could get hideously expensive, were high maintenance, they always leaked and you had to have a way to get rid of the heat. This was on very large machine tools which have all been replaced with electric drives now.
Remember that every time you change from one type of power to another, ie mechanical torque to pressure-flow and back to mechanical torque you lose a percentage of the original input energy. That's just the law of physics. If you stay with mechanical-mechanical-mechanical you will get more bang for your buck.
 

Nikson

Bronze Member
GOLD Site Supporter
Thank you gentlemen for more brain input, all your information will be considered and thought through... if any of you wish to talk on this subject person to person via phone, you are welcome to contact me 503.999.3244 (if I dont pick up due to work, text and I'll call back)

Thanks again,

Nik


p.s. if anyone got any hits on the OC12 rear end - let me know (sprockets with it would be a great help :))
 

Nikson

Bronze Member
GOLD Site Supporter
Nik, when I get some time I will elaborate on this.


So, I guess hydro would be out of the question, as I'm finding out that I'll have to run dual stage pumps for low/high speeds... thus staying with mechanical setup of some sort as Jeff suggests (Turbinator)

As far as towing, yes... you heard me right - I would like to see 15000lbs to be "okay" weight to be towable by the cat on a good flat surface with ski's on the trailer, e.i. camper trailer 20+ft length for one, or a stuck big full size truck out of the snow... (like a 2500/3500 on 40in tires)


Thus in my opinion, if I'm able to get the tracks to be driven by some sort of 4WD system by 4 sprockets (2 each track - front/back) - it would make much easier time for me not to worry about ripping track apart, as stress will be releaved to twice as many grousers vs one sprocket driven track.

I know I'm a bit crazy, but I have a certain dream of a cat, that will get me and few of my buddies where I want to, comfortably and possibly fast.

Now, 35mph top speed - is like a perfect conditions, flat area kinda deal... not expecting for a cat to just fly 35mph on some crazy terrain with 10ft drifts obviously... on other hand, I want a cat that can "dig" when I throttle it off the start and not worry about it falling apart, or tracks failing on me...

I know its a dream, but far from fantacy, and dreams are meant to come true!!! :)
 

MNoutdoors RIP

Gone But Not Forgotten
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With that kind of payload I would use nothing smaller than a OC15 differential
We use those on machines with planetaries that are in the 40,000 pound class

Or I do have some M24 tank differentials new but I think they would use your budget up in a hurry (pictured )

If you really want 30 mph speeds the Thiokol 600 series (OC15) will do it and handle higher HP but would require different tracks and undercarriage
 

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Pontoon Princess

Cattitute
GOLD Site Supporter
EITHER


always surprised me that, there is never any discussion about the bombardier snow coach, you know both Bombardier and Tucker started out building screw drive over the snow machines at the same time, funny thing, both snow machines looked very similar and today, one build fabulous jets and the other still builds over the snow machines

so, why not think snow coach style with aluminum monocoque body, diesel electric dual drive high speed terra styled tracks and independent suspension front end with hybrid delta skis, for compacting footprint for tracks and improved steering, and hydro suspension for terrain demands/side hilling/ride height...and use the diesel/electric system to power the sled tracks...

or instead of tracks, use paddle style sand tires, 4,5, or 6 wheels to a side drive (track) unit, all wheels drive, still using the ski steering...

and put a blade on it

no future here, just living in the past
 
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Pontoon Princess

Cattitute
GOLD Site Supporter
EITHER


always surprised me that, there is never any discussion about the bombardier snow coach, you know both Bombardier and Tucker started out building screw drive over the snow machines at the same time, funny thing, both snow machines looked very similar and today, one build fabulous jets and the other still builds over the snow machines

so, why not think snow coach style with aluminum monocoque body, diesel electric dual drive high speed terra styled tracks and independent suspension front end with hybrid delta skis, for compacting footprint for tracks and improved steering, and hydro suspension for terrain demands/side hilling/ride height...and use the diesel/electric system to power the sled tracks...

or instead of tracks, use paddle style sand tires, 4,5, or 6 wheels to a side drive (track) unit, all wheels drive, still using the ski steering...

and put a blade on it

no future here, just living in the past

with diesel/electric setup, you could easily set up the control system to be able to turn it on a dime and give $0.09 back. also Tesla has an open operating system that you could use.

the 'Sno-Bud'

no future here, just living in the past
 

PJL

Well-known member
The diesel electric idea is intriguing. How hard would that be to engineer?
 

Pontoon Princess

Cattitute
GOLD Site Supporter
all the engineering work has been done, from diesel electric locomotives to the Friskers car

just scale it to the Sno-Bud machine

what makes this work really well is the open source coding used in the Tesla
 

MNoutdoors RIP

Gone But Not Forgotten
GOLD Site Supporter
Diesel electric units are already being built for a number of years, just don’t drop them in the water. Prinoth makes one now, I also believe Pisten Bully has now made one. Direct current models are heavy AC three phase is not as bad.
If you look back about 3-4 years I discussed this on here


One one pictured is made from components from Prinoth.the wheels, tracks, final drives are from there current production sidewalk plows

https://thedriven.io/2018/12/04/this-pure-electric-vehicle-will-explore-antarctica-pollution-free/
 

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Pontoon Princess

Cattitute
GOLD Site Supporter
Diesel electric units are already being built for a number of years, just don’t drop them in the water. Prinoth makes one now, I also believe Piston bully has now made one. Direct current models are heavy AC three phase is not as bad.
If you look back about 3-4 years I discussed this on here

https://thedriven.io/2018/12/04/this-pure-electric-vehicle-will-explore-antarctica-pollution-free/

oh the great one, always has the knowledge and answers,

should help Nixon with his home built sno-bud machine

you are the best

no future here, living in the past
 

turbinator62

Active member
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SUPER Site Supporter
Like I said, every time you change the means of energy transmission, from coal to steam to turbine driven rotary mechanical to electricity to batteries to electric motor driven oxcart, you lose something. The Tesla is literally powered by coal/ natural gas/ hydro because that is where the majority of the power to charge its batteries comes from. In the process a very large percentage of the original energy input is lost to transmission/friction/heat. It just has the illusion of being environmentally sound because the power plant is out of sight in some other poor sap's backyard..(and has to burn more fuel to generate more energy than if the fuel were burned directly in the vehicle being powered.
Locomotives have to be able to deliver high torque to the wheels at zero speed. That can only be done with electric motors, steam, air or hydraulics.
Union Pacific tried a diesel- hydraulic locomotive set in the 60's but it was not successful. Too expensive, unreliable and difficult to cool. Diesel electric is the best technology we have for that application currently. Not super efficient, but they make up for it with the economy of scale. Five 3000 hp locomotives pulling 10,000 tons of freight is fairly efficient on a ton/mile/dollar comparison to other means of transportation, (not to mention impressive as hell) but not practical on a small scale.
It all comes back to the KISS principle. (engineering lingo for "Keep It Simple Stupid!")
 

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Cidertom

Chionophile
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As a thought exercise I've sketched out a concept of using two engines. One powers each track through a transmission. Turning is by varying the engine speed(s). Shifting the transmission is by a linked shifter so each transmission is in the same gear. The link could be disabled allowing one transmission to be in reverse for spin turning.



Manual transmissions would be the most efficient, and would be clutched by one clutch pedal.



Looking at the industrial yanmar diesels (40+/- hp ea) two side by side would be a fairly easy fit. The electronic common rail fuel systems are very responsive and reliable. By staying small the lighter aluminum block can be used as opposed to going a single larger iron block engine.



Don't really think it would be practical, but I don't think it is any crazier than some of the stuff that has been built.
 
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