my "lame-o" ZZM mods...

civicsr2cool · Post by **civicsr2cool** » Fri Oct 21, 2005 2:08 pm

am i the only one complaining about too much torque and turning radius in the steering?

Nasphere · Post by **Nasphere** » Fri Oct 21, 2005 3:13 pm

CaboWabo wrote:@ Nasphere.
Why'd I give you gallery space for 1 picture?
Use that shit holmes. I hate when images disappear 6 months to a year later.

Sorry, I didn't even think of that... Will do man..

crazydave · Post by **crazydave** » Fri Oct 21, 2005 5:57 pm

Nasphere wrote:
Clint wrote:nice, i had to trim my tx to 55% D/R to accomodate the wide radius, with some work on the knuckles i got it up to 75%. i'll have to finish it up like yours if i want 90-100% servo movement.
I also did this mod.

Although the results were discouraging. I found the weight balance to be more of a concern with most of the weight towards the rear of the truck, and with no differential, this mod does almost nothing to the turning radius. However, with my 'mid-motor' setup, it transfers a fairly even weight distro of 45% to the front and 55% to the back, which DEFINATLY helps with the turning radius, not to mention it's climbing ability.

It looks like you need to shave at the steering arm too. I shaved alot off of it. Left it pretty thin. Don't know if you can see that in the pic.

I'm just guessing your not getting as much steering as me, because you have the taller tires, and I had to shave at the sides of the chassis too, because the tires rubbed on the chassis.

That's interesting about the midmotor. I wonder if a forward mounted third cell would give the weight transfer needed.

I've already been thinking a chassis stretch should help keep it from pulling wheelies all the time.

SuperFly · Post by **SuperFly** » Fri Oct 21, 2005 6:17 pm

I've been thinking about the usual SuperFly easy route, and thinking about sticking a small lead weight up under the front bumper. My LHS sells them for pinewood derby cars that would work just right.

crazydave · Post by **crazydave** » Fri Oct 21, 2005 7:09 pm

SuperFly wrote:I've been thinking about the usual SuperFly easy route, and thinking about sticking a small lead weight up under the front bumper. My LHS sells them for pinewood derby cars that would work just right.

I suppose that might work too.

Screw it, I'm stretching the chassis, I've already made semi-plans.

Nasphere · Post by **Nasphere** » Sat Oct 22, 2005 7:02 am

To quote Clint again:

Clint wrote:nice, i had to trim my tx to 55% D/R to accomodate the wide radius, with some work on the knuckles i got it up to 75%. i'll have to finish it up like yours if i want 90-100% servo movement.

D/R means dirt/road, usually a trim knob on a regular propo TX, which also means your not running a stock radio... I-waver maybe? If so, i'de like to see how ya hooked up the feedback potentiometer and everything else about the steering...

EDIT: wow am i stupid, excuse me...
http://bitpimps.lixlink.com/pages/phpFo ... php?t=6871

crazydave · Post by **crazydave** » Sat Oct 22, 2005 8:36 am

Nasphere wrote:To quote Clint again:
Clint wrote:nice, i had to trim my tx to 55% D/R to accomodate the wide radius, with some work on the knuckles i got it up to 75%. i'll have to finish it up like yours if i want 90-100% servo movement.
D/R means dirt/road, usually a trim knob on a regular propo TX, which also means your not running a stock radio... I-waver maybe? If so, i'de like to see how ya hooked up the feedback potentiometer and everything else about the steering...

EDIT: wow am i stupid, excuse me...
http://bitpimps.lixlink.com/pages/phpFo ... php?t=6871

D/R = Dual Rate. What he's saying is, he had to minimize the throw of the steering, and after trimming his knuckles, he was able to increase the the amount of steering.

I think you already figured out the rest.

EDIT: I just remembered, I had partially FET modded my steering when I first got my MT, and was trying to figure out the FETs. That could be helping pull my steering to full lock, after I did the trimming job.

Nasphere · Post by **Nasphere** » Sun Oct 23, 2005 6:54 am

Ok pimps, this should be our new goal...

Clint · Post by **Clint** » Sun Oct 23, 2005 7:38 pm

crazydave wrote:
Nasphere wrote:To quote Clint again:
Clint wrote:nice, i had to trim my tx to 55% D/R to accomodate the wide radius, with some work on the knuckles i got it up to 75%. i'll have to finish it up like yours if i want 90-100% servo movement.
D/R means dirt/road, usually a trim knob on a regular propo TX, which also means your not running a stock radio... I-waver maybe? If so, i'de like to see how ya hooked up the feedback potentiometer and everything else about the steering...
D/R = Dual Rate. What he's saying is, he had to minimize the throw of the steering, and after trimming his knuckles, he was able to increase the the amount of steering.

You hit a max on what you can cut out of the chassis to make the steering radius shorter. I hit a point on mine where it turned nice and tight, but then I lost the internal support of the steering rod. It would get caught up at full lock and fall off the knuckle. So I had to glue some supports back into place, which negated the benefits.

What we need to do is move the steering rod above the servo and above the knuckles. Then you can cut as much as you want out of the chassis.
Ive got a few ideas I want to try out, something more traditional of larger r/c's. Just using a single steering arm to move both wheels is a bad design. The knuckles need to be tied together, and then a use steering rod to move the whole assembly. Much less slop this way.

Nasphere · Post by **Nasphere** » Sun Oct 23, 2005 9:27 pm

Clint wrote:What we need to do is move the steering rod above the servo and above the knuckles. Then you can cut as much as you want out of the chassis.
Ive got a few ideas I want to try out, something more traditional of larger r/c's. Just using a single steering arm to move both wheels is a bad design. The knuckles need to be tied together, and then a use steering rod to move the whole assembly. Much less slop this way.

I'm not visualizing what you're saying, I see the arm bieng over the knuckles, but how would you add an arm to control that. Ball joints are almost non-existant at this scale... Also with an 'extra' arm, it will increase play. The smartest approach that I can see is using the old school push cart steering design (rod attatched to servo, pokes through plate with a slit attatched to steering arm).

Is it possible to make the ZZM articulate correctly without centering the drive shaft? the driveshaft is near impossible to move because of the way they're built...

Cheesehead · Post by **Cheesehead** » Tue Oct 25, 2005 5:40 pm

That mod is ingenious. I'm going to have to try it.
Hmm...now all I need is an iWaver compatible potentiometer that I can attach to the steering, and I can wire mine for fully proportional control!

Also, I should mention that the only articulated ZZMT I have seen had the transfer axle moved to the center. You'll likely need a jewler's saw, a dremel, a plethora of drillbits, and a bottle of asprin.

EDIT:
You should post a tutorial of this mod. You'd likely be cannonized for it.

Nasphere · Post by **Nasphere** » Thu Jan 12, 2006 3:01 am

Hell, i did some more... Same truck of course.

First i cut out the front a little more.

Modded out one of these:

Checked clearances.

Didn't work, so I cut a little more out. It fits!

Added an SE board shortly after:

After the addition, I took this short, crappy video:

http://bitpimps.lixlink.com/pages/phpGa ... 292&pos=23

Nasphere · Post by **Nasphere** » Thu Jan 12, 2006 3:55 am

I've run into a snag... If you watch the movie, that little turn at the start is lock to lock... It will need some serious feedback reconstruction. I think an op amp as a rate controller should work. I've tried adding 3K resistors to each side, I even tried 5K and the steering is still crap... So an op amp (set as a de-amplified buffer) to rate the steering should work.

EDIT: Holy shit!! I just weighed this thing! 32.4g on the front and 33.1g on the rear!! I've achieved a 50/50 weight distro!!! WOOHOOO!!! lol that's freakin awesome!!

Michael.mt2k · Post by **Michael.mt2k** » Thu Jan 12, 2006 8:59 am

Incredible work!

great pics!

Nasphere · Post by **Nasphere** » Fri Jan 13, 2006 3:27 am

Near finished... I need a few more parts. Have to make the steering filter still and hopefully a DC mod. I installled a 150mAh lipo, which gives it TONS more torque.