I know some people don't understand the reason or purpose of ceramic bearings, and would just rather buy new Avid bearings every month or so, but if you need a quality bearing, and don't want to have to replace it...ever, grab an Acer ceramic bearing, or even a Boca ceramic bearin...hell, even the Avid ceramic bearings may be good, but I have never tried them, just Acer & Boca.

Front Driveshaft:

I made a long driveshaft for the front out of a Muggy center rear driveshaft that I cut in half (4mm diameter) and a piece of this:

8mm aluminum tube (2mm wall thickness)

I drilled and tapped three set screw holes in each end of the Al tube, ground flats on the Muggy half drive-shafts, and had to hammer them into the Al tube. Then I used red Loctite and 4mm set screws.

Length is about 10":

http://i779.photobucket.com/albums/y..._4428Small.jpg

Red Loctite and assembly:

http://i779.photobucket.com/albums/y..._4449Small.jpg

Installed in truck:

http://i779.photobucket.com/albums/y..._4452Small.jpg

This is the part that I probably have the least confidence in on the entire build. I hope it holds up :wink:

Green loctite "sleeve locking" may also help unless you are just worried about twisting the alu. tube.

I'll keep that in mind if I need to make another one. I don't think the Al tube will twist - the walls are thick - but I'm not sure. I'm more concerned with the muggy drive shafts twisting out - so "sleeve locking" might be want I want. Thanks.

muggy
 

You should weld the ends with a stainless steel hollow tubing. I had one with a brazed weld and it broke off. I had one tig welded and I never had problem with it. You can also mig weld it if you want. I don't think the aluminum tubing will hold up, i think it will twist or your setscrew won't hold up under big tires and lots of power. I could be wrong though. Goodluck.

Considering the torque these motor produce, i wouldnt be happy with a hollow tube. i think the tube would twist before the ends brake off!

What is the process if you pay someone to do it?

If I could weld steel, I'm sure I would have gone this route. As it is, I'm trying to do this project without paying for custom parts, so I'm using materials and processes available to me. If this Al tubing twists, I'll probably have to get something custom made - so thanks for the advice.

Here is a picture of the cross section of the tubing, just so people aren't imagining some thin-walled Al tube:

http://i779.photobucket.com/albums/y...1049470_tp.jpg

hmmm that does seem pretty thick! looks as if things should hold up then! Gd luck and keep us posted!

I hope it does - and I hope to get this thing up and running within the next two weeks (I should have the time to work on it) to see how it holds up.

So I actually had some time today to get this together enough to give it its first test run. I ran it on 6s geared conservatively around the yard. Everything worked like it was supposed to. A few things need to be tweaked but I'm happy. I like the mechanical brakes - easy to set up and worked well. I've never used them before because I never ran nitro.



<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/5YZlSGS4xA8&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/5YZlSGS4xA8&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>


And no, I didn't hit my wife with it (she was filming). :na:

Good work man. One complaint. That vid is a bit of a tease! Was hoping for more speed, or more ripping it up with that big motor. Lol. Keep up the good work and keep us posted.

Sorry - have to wait until I get the rollcage fitted, then I'll let 'er rip

:tongue:

Lookin good keep those vids coming:whistle:

Wow that's impressive work and really nice project! I may have missed it (hard to read thouroughly while my son is running around about to crack his head open), but what motor is that? It's ginormous!

I'd like to convert my 1/5 scale gasser to brushless. I love the runtime of the gas motor, but hate the pull start and having to tune it.

looks gd! let it rip!!! haha..

Neu 1527 1.5y (825kv)

I'm looking forward to seeing what it can do on 8s and 10s!

I have the rollcage almost installed - a couple of more brackets to secure the center piece still needed. Here's what it looks like:

http://i779.photobucket.com/albums/y..._4486Small.jpg



Another thing - I looked at the front tires after my first 15-20 minutes of running the other day and they're getting chewed up already. The rear tires look fine. I know the fronts are designed for the 2wd Baja 5b, but I wasn't expecting to wear them out so fast. I might try taping them to see if that helps - I know some people running the 5b tape their tires. Otherwise, I might have to run the rears all around.



:neutral:

nice cage... where did you get it from?

it's just the stock baja 5b rollcage - not too expensive on eBay.

I just put on some of the rc-raven springs and I think I'm going to like them. The yellow Losi springs weren't quite enough. These are stiffer and have much more room to adjust with the preload adjuster nut.

rc-raven springs

I took it out for another test run around the yard on 6s with the rc-raven springs - they do the job - a great $7 purchase. I don't have a scale, so I haven't weighed this thing yet - but I'm estimating about 17-18 lbs. Still haven't finished the last two brackets on the rollcage - hopefully soon.


Edit: Also screws kept coming loose from muggy steering tie rod (I had even put a little blue loctite on them last time), so I decided to tighten them good - until I snapped one of the screws heads off with the rest of it in the bushing. So I got rid of that whole set-up and installed a titanium tie-rod with adjustable rod ends. I used 3mm screws inside a 3/16" plastic sleeve inside the bellcranks and 3mm locknuts. Hopefully it will stay tightened now.


Next edit: I took it out in the yard on 8s geared conservatively - everything worked fine - the steering mod worked. My only issue right now is oversteer. I was tightening down the pre-load in back, but a quick read on fixing it tells me I was going the wrong way - I needed stiffer front and softer back to correct it. Hopefully I can work that out.

Here's how I attached the baja 5b rollcage and its wing mount to the muggy wing mount for what I think is a very sturdy wing mount (I'm waiting on a baja wing in the mail - I put a 1/8 wing on it but it looked too small).

I cut the muggy wing mounts and drilled holes through them for my extra orange tube (from the stock baja 5b rollcage) to fit through and screwed through the baja wing mount.

http://i779.photobucket.com/albums/y..._4503Small.jpg

The baja rollcage is also attached to my rear aluminum shock tower with one screw on either side:

http://i779.photobucket.com/albums/y..._4502Small.jpg

And you can see my new black rc-raven springs installed (also my custom esc mounting strap).

Wow, that motor is wild! Awesome truck.

How is the center diff working out with 100k silicone? I know you said your front tires are getting chewed up quickly, is it unloading too much up front?

Thanks.

100k seems good so far in the CD - but this may be because I haven't put enough power through it to see the front end lifting up - so I'll have to wait to see about any unloading problems. I think I'll have to really try to get wheelies with this thing - I have the weight pretty evenly distributed front to back and with as long as it is. This is fine by me - no interest in wheelies.

I taped the front tires and foams to keep ballooning to a minimum and have stayed on the grass mostly - so front tires don't seem to be getting worse - but we'll see.

you taped the foams as well as the tyres? I heard somewhere that it was a bad idea????

Many others have done it - I've never heard of problems. And if I'm taping the inside of the tires, what difference would it make if I also put tape around the foams? I can't see a possible problem.


edit: you can also see in the above pics part of the heat sink I made for my motor (when I take the motor out again I'll take pics and show how I did it)


another edit: Since I mentioned the rear shock tower - it's this one (no longer red, though):
dynamite lst shock tower

I got the rollcage finished and the wing installed. I took it to the park for the first time and ran through 8s 5000mAh in about 25min geared for 40mph. The oversteer isn't as bad with the rear shocks softened, but I'm going to do some more testing as to how I can reduce it (or get used to driving it). Outside temp today was about 81F. After I was done, temps were:
batteries 98F
esc 112F
motor 132F

I will gear for higher speed on 8s and give it a try.

Here it is, finished:

http://i779.photobucket.com/albums/y..._4505Small.jpg


edit: I looked at my new rollcage mounting brackets in the center after driving it and rolling it only once - and they're bent. So instead of 1/8" Al angle brackets, I guess I'll go to 3/16". Well, now that I'm finished building the truck, I guess I'll start fixing it.

:yes:

Looks great!!! yea with those temps, seems you can get more speed out of the motor without hurting anything!!! GET SOME VIDS UP!!! looking forward to seeing this go

Ok, so I want to try to tune this thing a little to reduce the oversteer by changing the diff oil weights. Right now I'm running 10k/100k/10k. Do you think I should try reducing the oil weight in the center or the rear diff first? From what I read, either should reduce oversteer. Any thoughts are appreciated - thanks.

:great:

I just took this out again - I geared it up to 51mph on 8s. That gearing really woke this thing up and it can move (I don't know when I'll have vids). It was really squirrelly at high speeds on low grass - the rear tires were really ballooning, so I'm going to have to tape those too.

After about 20 minutes, temps were:
batteries 112F
esc 119F
motor 152F

I'm happy with the speed and power and temps with this gearing. I'll have to try it on 10s at some point geared for 50mph and see it the motor likes that better. At this point I don't see a need to gear for higher speeds.

I taped the rear tires and I mixed up some thinner diff fluid for the rear - probably around 2k weight. It helped reduce the oversteer significantly and it now handles much better. The only issue is when I punch the throttle, it can easily go off track. I don't know if reducing the center diff weight will help this, but that's what I'm going to try next.

I've been tuning and testing this and have it where it handles well on dry grass on 8s geared for 50mph. It's still twitchy at high speeds if I punch the throttle (lots of power!) - but it's very controllable. I'll continue to tweak it but I'm happy.

Temps after driving it pretty hard for about 20mins (90F ambient):

batts: 114F
esc: 132F
motor: 160F

I also checked my diffs' temps and was surprised to see my center diff was 190F (rear - 145F, front - 130F). I have 25k diff oil in there now - I may have to thicken it up again if the CD temps are a problem.

Anyone know how high is too high for silicone diff oil - or diffs in general? I expect the silicone can go much higher than that - it's used for cooking utensils rated for 400F. I've never paid much attention to diff temps before, so I haven't given it much thought.

Edit: I'll get vids up later this week or weekend when my wife gets home with the kids and the video camera!

First carnage
 

I was driving on some soccer fields, getting it up to full throttle for some speed runs across the field. The grass is very dry and dusty - poor traction. So I was about to finish up, but did a couple more runs, the last of which, I thought I had everything under control, but drifted a little at high speed - into the soccer goal post. :oops:

I was expecting major damage as I saw one wheel + other parts flying in one direction and the rest of it in another. So I was happy to see it was mainly the plastic arms that broke and a bent driveshaft:

http://i779.photobucket.com/albums/y..._4511Small.jpg

Then I got home and saw the right rear driveshaft :surprised:

http://i779.photobucket.com/albums/y..._4512Small.jpg

Those arms are bent and need replaced too. Luckily I have a box of extra arms and other parts - I'll have this back together to take it out tomorrow. :yes:

Now that is a trick!! Doesn't all the bad stuff happen on "one more time"? That's the way it goes for me.

-JB

Me too!! :yes: Blew the rear diff in my e-revo doing "one more" wheely, and the cd in my ofna buggy doing "one more" hard dragster style launch. All this past weekend. Got the parts laying around and a few days before the weekend, so its all good.

Good to see the carnage isn't that bad though. I don't think you'll be able to tune out "all" of the on power drifting. Its inherent in shaft vehicles, especially ones with huge power. Thats why the touring cars are all going to belt drive, to get rid of the effect.

ouch... at least its minor damage. How that happend to the shaft iscrazy!!!

overdriven, could you please explain a little furthur about the belt driven touring cars and how their performance differs to shaft vehicles

As the shaft spins it creates force(centrifugal?) to one side of the vehicle and it slides. Atleast that's what I read on drift forums.

I got this fixed up this morning and am pleased to see that there was no major damage. When it happened I was expecting to see broken bulkheads, etc. But just arms and driveshafts. I recently put 4mm screws through the chassis into the bulkheads - I think this made a difference (the 3mm screws I had there had bent slightly from a relatively minor impact previously). With a wreck with something this heavy at high speeds, something has to give. So I'll stick with plastic arms and let them be my weak point - they're cheap and I already have a bunch of extras (no Al arms for me!).

To my understanding it's not centrifugal force that causes shaft driven cars to drift or wander. It has more to do with the torque being transmited through the shafts under acceleration and how it acts on the chassis. The effect is more gyroscopic than anything.

Either way, it's created by the motor trying to accelerate the car through the drivetrain. If you've ever powered up an electric motor while not attached to anything and watched the whole thing spin around, that's kind of what's happening here. Now picture that force in a typical shaft vehicle and you can see that force wants to push the vehicle to the side.

During acceleration, a powerful motor may already have the tires on the edge of traction. This makes it easier for this gyroscopic effect to Break traction and push the car to the side. Touring cars have a relatively small tire contact patch for their size and weight. They are also sensitive as far as handling goes, so brushless motors almost forced these cars to belt drive. Brian's creation weighs alot but is just so powerful and on grass so he's seeing the effect also. I've seen it on my 1520 powered erevo on 6s as well.

I'm not sure if belt drive creates any gyroscopic effect of it's own. But the layout of the motor shaft and pulley shafts means any forces would be directed to the front or rear not to the sides.

I read the entire thr3ead and didn't find the answer.

Hey brian015- you are running 23mm hexes in a 24mm hex wheel. Did you do anything about the size difference or are you just letting her buck? I want to run those wheels/tires on my LST. Thanks! -Harold