Propject 4ws (4 wheel steering)
 

Forgive me if it's already been done.
Some pics to get you started.
Will docment my progress as I go along.

Notes: The drive shaft is not dead center.

Any ideas thoughts welcome :D

http://www.MyOnlineImages.com/Member...00631.-jpg.jpg
http://www.MyOnlineImages.com/Member.../DSC00632-.jpg

For some reason the images don't seem to be parsing properly.

Option1
To keep the drive shaft in line.
Dosen't work, it will be trying to tear itself apart.

http://www.MyOnlineImages.com/Member...mages/opt1.jpg

Option2
The chassi will be offset. Won't do.

http://www.MyOnlineImages.com/Member...mages/opt2.jpg

Option3
Now to track down the parts.

http://www.MyOnlineImages.com/Member...mages/opt3.jpg

Option1a
Moved the gear to the other side.
Now I'll have to figure to power that driveshaft.

options
the steering system out of a zz se. Quiet slow but torquee
the teeth spacing on the gears are the same as 1/10 gears
have a micro rc tank, will dig that up and see. Lots of torque

http://www.MyOnlineImages.com/Member...ages/opt1a.jpg

Hmm...looks interesting

One question:
Where is the big drive gear/motor?


and as a possible solution just use 2 motors and drive the front/rear axles seperately like a clod buster(it worked well for tamiya)


4ws
4wd
twin motor
4 cell
=
max fun

looks good, keep the pictures coming

my truck is just laying here in a heap of parts right now untill i decide what i want to do to it.

Darn caught me out ;)
i was hopeing some more creative than me might figure that one out.
Looking thru the tttt forums to try and get some ideas.

Ahh yes, the clod.
Mine's in need of some tlc.
Stripped the gears after running at 50kph for too long (2 hrs).

Well your belt idea is good and you might be able to find a very thin small o-ring at the hardware/auto/motorcycle store.Making a pulley for the shafts would be easy.

The more I look at mine and think about it the more I realize that there is not a whole lot of useable extra space on those trucks.

I'm still trying to decide on either a 4ws/4wd solid axle or a wider 2ws/4wd independent suspension truck.

has anyone checked to see if the ZZ/se steering motor pinion would mesh with the ZZ/mt steering lever arm?


I just want a micro truck that can handle that little obstacle course in the picture.an obstacle course

Just checked, pinion<>gears don't mesh :(
But you can easily swap pinions, or resolder the motor.
If you want propo, now that gets tricky but it has been done.

The stock trucks are build for that course I think. :)

I was thinking about a dual steering design, but haven't considered the offset driveshaft, that's gonna change my thought process real quick.

I was thinking of a mid engine design. With the motor laying flat side against the side of the chassis, I figured there should be enough rough to for one of them Li-Poly batteries everyone has been sticking in their monsters. Those batteries are really thin.

I was thinking the motor would be driving a large gear, like the idler, to drive the drive shaft. I'm think with the offset driveshafts, I could use the big gear to drive both drive shafts, but the the gear would have to be center mounted, and that puts all kinds of holes in my plan.:(

hey k_manNZ, i know this is kind of irrelevant to the thread but.. i noticed that you're in auckland. which part of auckland are you in? im in east auckland around howick. i was wondering, where do you buy all you radioshack r/c stuff? i bought my mt on a visit to the states.

it_thing_stuff

I feed my addiction with the help of ebay.
:D

Any more progress/pictures.

GearGuy2005,
what about the big drive gear on the rear axle and the slightly smaller idler gear, without those that truck would never move.

I myself am leaning more and more towards an Emaxx type setup with the center driveline and suspension arms all the way around.Even then the big gears get in the way unless the motor and driveshaft are mounted vertical directly over the axles and that might work but then the steering issue comes up.

Unless someone finds a very high torque micro motor to cut down on the needed gears.I wonder if those motors for the SuperSlicks have more torque.
maybe someone can find a way to drive the front axles just like the back.


I have a lot of ideas but untill I get all the parts drawn up and into my cad program I wont know exactly how it can all fit.

i dont htink it would work unless you run a gear in the center...wich would take away all your ground clearence. you could put the gear in the center next to the 45 dregree gear thingy...but that would make you not much ground clearence in the center of the axle...... you could do this...it might work...put a worm gear on the motor and a tiny gear on the center drive shaft....it would be geared plunty low and you would still have tons of clearence....but you have to put the batteries somewhere else.

Good to see there is some interest. :D

Here is the pic of the micro tank gearing system.
I will most likely use this as its the easiest to do.
It won't be the fastest thing around. 64:1

Notes in pic, looks like i'm ready to send my two MTs to the chop shop.
At least I had about 1 hour of fun with them if it all goes horribly wrong.

slugbugg
imo I think the stock MT motors have more power than super slicks. Just look at the size :)
I don't have a SS motor to verify tho.

http://www.MyOnlineImages.com/Member...ges/Tank-b.jpg

Any feedback appreciated.

that last pic looks like it would work...kinda what i had in mind...but geared lower than you would want. if you run the worm gear right on the motor and a small gear on the drive shaft it would be a little faster with a ton of torq...the 4ws sounds like a good idea...but i wouldnt take my only 2 zzmts and my tank to make 1 4ws mt that might not work....

theone&only....

I'm going all out on this one.

Don't forget a ZZse too ;)

So let's see
2x ZZMT $50
ZZse $25 Just for propo speed.
FET mod $20 Not steady enough to do it myself.
Tank $10
Lipo $8
Shipping to the other side of the world $50

that's one expensive micro. :(

Good thing i'm an old gezzer

4ws reduex?
 

So, what happened to this project? Was it a success? I'm about to start my own and was just wondering.

Lost interest in this hobby before I can finish.

Unfortuantly I have over us$300 worth of zz I can't sell to anyone.
No demand here in NZ :(

Ack!
 

So here goes it...

Two ZZMT chopped into pieces. The new truck consists of two front ends, one turned around with the drive shaft re-routed, and a center mounted motor compartment. See Pics.

The reversed font end does two things. Keeps the drive direction the same as the other end so it doesn't try to go in two directions at once. And, it shortens the wheel base, which is still slightly longer (1cm) than a stock ZZ.

Right now, the whole thing is held together with a few plastic strips, no electronics, but the gears all mesh good, and all 4 wheels turn like they should.

The next step will be to patch the chasis back into one piece, and then mount the PCB. Hopefully video will follow...

exposed
 

and the bottom...

That so awesome. I didnt expect it to be that complicated. I am planning on maybe making a four wheel steering truck with the motor in the middle and too front ends stuck together. It would bee nice to have more pics and more of an explanation of what you did but anyway, thats a really nice truck. I am very interested in what you will do to wire the two steering motors and how they will work.

Nice work, Greg

oh yes
 

yeah, it's complicated, so many things have to spin the right direction, and not interfere with a dozen other moving parts. I think the hardest part is finding a way to drive the gears.

I'll probably just run another servo motor off the front. It will be 4WS all the time, but at this stage, any 4WS is progress.

I'll get more pics up IF and when this thing actually works.

That's some good work there man, don't give up so close ;)

progress
 

shortened the wheel base further so it is now the same as a stock truck.

threw electronics in a for a quick test...See Video

gearing
 

this was almost a problem, ok it WAS a problem because the tires hit the gears. Had to modify the layout a little so the drive gear is inside the transfer (stock is the other way around). This is actually not a bad thing as I'll probably be adding gears to this to drop the ratio to around 400:1, and I'd have to change the configuration anyhow. Also had to turn wheels around so they stick out a little further from the chasis.

bottom closed
 

you can clearly see the three sections here.

Notice the two "font ends", ones in back, the other in front. Though they are in the same orientation, one has the drive shaft coming out the back while the other comes out the font. That's the key in getting everything turning the right way.

next phase
 

- major cosmetic work on the chasis

- mount the PCB and battery (might go three cells to compensate for two steering motors)

- mount body

- drink heavily

idea
 

As a side note, I discovered that a center mounted motor is ideal for articulation. While experimenting with that mod in the past, I noticed that with all the twisting that the rear end goes through, the motor wires tend to snap off. Moving the motor to the middle like above would eliminate that problem.

I'd actually articulate this project, but I don't think my gear meshes are up to it. The third of the chasis that could actually twist (and wouldn't hit the drive gears) is the one where the custom drive shaft exits out the opposite way it should, so it's not as clean as the factory setup. Plus, once I start adding gears, I just don't think there is enough room. Putting the drive gears in the middle certainly takes up a lot of space.

Looks very cool. I did an articulate design. took about 24 hours all added up. How long have you spent on that thing?

P.S. Get some in action video when you are done.

"wheel clearance problems"
 

Steve--

Would it work for your mod to add wheel "extenders" instead of flipping the wheels?

I gave it some thought when I did my dual wheel mod, and have revised my design considerations since:

1. Insert a plastic rod snuggly into a brass tube.
2. Cut the rod/tube combination to the desired length.
3. Drill and tap for a 1-72 thread completely through the rod.
4. In one end, screw in a short way a long 1-72 machine screw.
5. Cut the threaded part of the screw so that it would project from the rod/tube a length comparable to that on the stock ZZMT axle (save the remainder of the machine screw).
6. Build three more.

Another alternative:

1. Cut the tube to the desired length then insert the plastic rod.
2. Leave the rod protruding from one end of the tube, then cut the other end flush with the tube.
3. Drill and tap, as above.
4. File/sand flats on the protruding rod to fit in the slots in the wheels.
5. Insert and cut the machine screw, as above.

The brass tube should provide rigidity for the plastic rod and help prevent breaking the rod from any accidental pressure.

Best wishes on your mod! I enjoy exploring your creativity!

chilli
so many mods . . . so little energy

If you did the sleeved driveshaft design, you might be able to have close enough tolerances to keep from messing up your gearmesh. Maybe.


I've been really watching this thread, your solutions to making it work seem so beautiful, simple, and elegant. *drool* (Man I gotta build one of them!!!) But the one thing I'm having trouble with is how you're going to wire your steering motors.

I hit LEFT on controller, the front axle throws LEFT, the rear axle throws RIGHT? Or if they both throw left wouldn't that make the turning radius either absurdly huge or nearly non-existant, but it'd be better for high-speed running.

Steve--

I'm watching with great interest your progress.

Since you apparently have two unused motor wells available, do you think it possible to put them together with articulation along the other axis, much like large tractors have articulated steering?

A steering servo might be turned 90 degrees to "pull" and "push" the other section, providing the turning. I imagine it would require a very strong servo to do that.

The MT could even be easily articulated to twist as well as turn (I'm building the "hinge" from small brass pieces).

It seems to me an advantage to this method would be the lack of a drivetrain since two motors are used (as well as two sets of batteries wired in parallel). The downside could be weak steering unless a hefty servo could be used.

chilli

I ran the two steering motors off the same place on the PCB. SO, turning left means the front wheels turn left, and the rear wheels turn right. It shortens the turning radius dramatically, which is what it is supposed to do.

Progress Update
 

And that was that. I put the electronics in, the body on, and went for a test drive. What I found was somewhat disappointing. While the truck certainly turns really well... it somehow lacks something I thought it would be.

The paltry little spring suspension on all four wheels is pretty much useless, much like it is on just the front. Maybe softer springs would actually work better, but there's bigger issues anyway.

Power. Much like the stock version of the truck, it lacks power. I even put three cells in it, but while fast, it still doesn't have the power it needs, which means I really need to gear it down, waaaay down. But there are other issues.

Gearing. Moving the drive gears into the center and away from the wheel has seriously compromised ground clearance. AND there are still more issues.

Stance. I had to widen the stance so that the tires would not rub on the gears. Good for balance, bad for ground clearance as it now cases on each and every little thing.

Run time. Seriously compromised with two steering motors.

I guess I thought 4WS was the "holy grail" of mods. I was stoked about getting it to work, but it doesn't really enhance performance any. Sure it turns well, but in all honesty, I get more satisfaction out of turning badly and plowing into and over everything in my path. This truck won't do that because of the issues listed above. It would require relocating the drive gears, adding more batteries, gearing way down, and articulation, to even come close to the performance gains you get from articulation alone. Gearing down and adding articulation to a stock truck almost instantly makes it a rock crawling beast. While I certainly won't say it was a waste of time, the minimal gain doesn't even come close to justifying the effort put into it.

So it's back to the drawing board, though perhaps with something to build on. Much like the problem of [driving] the truck was a hinderance before, it still is. Moving the drive gears up is no good because of space constraints within the body. The only solution I can see would be one of multiple smaller gears, but then space between the wheels is still an issue. Pullys, worm gears...maybe. One thought I think I came across on here was using a servo or stepper motor for the drive motor. Stepper motors usually have mad torque and are very slow....two things I need in a crawler. Maybe big gears wouldn't be needed at all?

thoughts?

I do NOT mean anything against yours by posting this, but check out what this guy did.

http://549.rapidforum.com/topic=100379626552

Sorry, it IS german so you might need a translator

Absolutely no offense taken...that's AWESOME! German engineering rules! I attempted to build mine using as many ZZ parts as possible, but it's obvious what can be done if you're willing to fabricate a little. At this stage, we might as well just toss the whole chasis out the window and build it (right) from scratch.

What did this guy use for a battery?

microsash is using a lithium polymer cell - 140 mAh as far as i know.

The truck has one major problem - the articulation has an enormous influence on the steering. You can only solve this problem, if the servo is mounted/connected to the axle. As it is done on the larger (1/10) crawlers.

He has modified his concept and is now using a seperate servo for each axle.

http://mitglied.lycos.de/viktoria/trialmog2.jpg

Here is the coresponding thread http://549.rapidforum.com/topic=102177466221

But this increases the overall length/size :( It isn't a zipzap any more

diets - the smaller the servos, the smaller the truck :D

action video
 

finally took it out for a little video shoot...


http://www.withoutdreams.com/images/...051115-001.jpg


Video (400k WMV)

Nice vid! Turning radius looks wicked!!!

Noticed it got high centered a couple times. While you were modding, did you do long travel suspension on it? Softer springs and wheel weights would help too.

How about some closeups of the body?

This is the truck that just plain has issues. The fact that there is even a body on it right now is a mystery. It has as much suspension throw as it's gonna get, but with the stock springs, it doesn't even move anyway, so until I find softer ones... also, the drive gear, since it's been moved to the middle of the chasis, it has nothing to keep it off the ground, and because it hangs so low, its destined to get caught up on things.

Also, seriously under powered. It runs on three cells, but it's just not geared low enough to matter, and because the motor is under the PCB, raising it even a little to get some more gears in there is gonna be tough.

The body (dubbed Caged Fury) was lengthened about 1/8 of an inch to accomodate the batteries that now sit where the steering motor is (front and back). I'll get some pics once I get the batteries for the still camera.

I haven't given up on it completely, I'd still like to see articulation and lower gearing, just not sure if I can do it in such a small package. I'm thinking it needs to be built from the ground up with those ideas in mind.

One More Time...
 

Reworked the drive train using a worm gear, and added articulation. Motor and gears are contained entirely within the chassis, which remains stock in length. I have no idea about the gear ratio of a worm gear, so it's pretty much anyones guess if it will go. The articulation AND 4ws combined creates some interesting problems.

in pieces. The rear axel (not pictured) had to be custom made by pulling the hub off, turning the grear around and moving it to the other side. It sounds weird, but it's the only way to get the wheels spinning in the right direction with one drive shaft.

http://www.withoutdreams.com/images/ZZMT/parts.jpg


motor will go someplace above worm gear

http://www.withoutdreams.com/images/ZZMT/motor.jpg


top view

http://www.withoutdreams.com/images/ZZMT/top.jpg


bottom view. The white mess on the rear end is where the bearings are for the drive shaft. The chassis was built up around those bearings, needed to be strong because it's the only thing holding the rear end on.

http://www.withoutdreams.com/images/ZZMT/bottom.jpg


4ws

http://www.withoutdreams.com/images/ZZMT/4ws.jpg

articulation

http://www.withoutdreams.com/images/ZZMT/art.jpg

Nice work. How does it perform?