My new build - Karnage Bodiless Comp Crawler
 

Ok, I finally got my second version of my bodiless chassis cut, painted and everything all together. This build started as an AX10 RTR, and fairly quickly evolved into my Chameleon build. There were some flaws in the design that have been fixed in this version. (More on that later)

Here's the specs on the crawler:

Chassis - Custom two-off Bodiless QVP Chassis
Skid - Ghetto Home-Cut Tivar 88 (UHMW-PE) Dual Triangulation skid
Links - White Delrin with stock axial rod ends
Axles - AX10 stock axles
Servo - Hitec HS-645MG with aluminum horn
Wheels - Axial stock 8-hole beadlocks, dyed
Weights - Stick-on lead weights, 9oz each front, 6oz each rear
Tires/Foams - Hot Bodies Rovers White with HB stock foams
Shocks - Stock Axial plastic bodied shocks, full droop with two internal springs under the piston, added a spare piston under the fuel tubing to prevent it from flipping over the rod end.
Transmission - Stock Axial with steel outputs
Motor - 55T Axial crawler motor
ESC - Axial AE-1 Stock RTR esc with Novak Smart Stop 2 cell lipo cutoff
Receiver - Traxxas 3ch mini receiver (27mhz AM)
Transmitter - Traxxas TQ3 with 3rd channel modded with epa's and 3rd position switch, painted flat black.
Batteries - 2 Cell 1000mah LiPo (2x Excalibur brand, 1x Losi brand)
4-Link Plates - Custom one-off front 4-link plate with offset battery mount, custom one-off rear 4-link plate both in Lexan.
Dig - DNA with Steel Internals
Dig Servo - JR Sport ST126MG High Torque Servo
Dig Servo Mount plate - Stock axial servo plate mounted to dig case

Coming soon:
New ESC - probably going to get a Tekin FX-R 45 or 55 combo for it so I can have drag brake and programmability

Ok, enough talk, now for some pics:
http://img.photobucket.com/albums/v2...e/S5002241.jpg

http://img.photobucket.com/albums/v2...e/S5002240.jpg

http://img.photobucket.com/albums/v2...e/S5002243.jpg

http://img.photobucket.com/albums/v2...e/S5002245.jpg

http://img.photobucket.com/albums/v2...e/S5002249.jpg
Very low profile, barely anything above the top of the tires.

http://img.photobucket.com/albums/v2...e/S5002246.jpg
Narrow, but still comp legal, nice and low COG.

http://img.photobucket.com/albums/v2...e/S5002251.jpg
Custom rear 4-link plate (Lexan)

http://img.photobucket.com/albums/v2...e/S5002253.jpg
Side panel for comp rules, I like Monster Assault...

http://img.photobucket.com/albums/v2...e/S5002255.jpg
Front link set-up, you can see all the electronics mounted on a plate zip-tied to the link.
*Ignore the poo colored links, they will be replaced very soon.

http://img.photobucket.com/albums/v2...e/S5002257.jpg
Rear link set-up. Once I get the new skid cut, there will be a little better triangulation for a little more stability.

One thing that is hard to do with these style chassis is to get a good place to mount the front suspension, but still be inboard enough to clear the tires at full turn, yet provide stability and articulation. This is how to solve the problem:

http://img.photobucket.com/albums/v2...e/S5002260.jpg
At full lock, the tires don't hit anything. This is because the body panels are inset from the chassis plates to allow the suspension to mount at a better angle without any bind at all.

http://img.photobucket.com/albums/v2...e/S5002262.jpg
All the weight is low and below the "hood" line, which is pretty close to the center of the tire.

http://img.photobucket.com/albums/v2...e/S5002263.jpg

http://img.photobucket.com/albums/v2...e/S5002265.jpg

Some of the stickers that I will have made for this:

http://img.photobucket.com/albums/v2...ateKarnage.png

http://img.photobucket.com/albums/v2...arnag3Logo.png

Ok, back to talking. The differences in this version compared to the first version:
Overall Shorter Length - To clear the axles better if I ever wanted to go to an MOA rig
New Offset Body Plates - to allow better shock placement
More material around holes - the first version had the brace holes too close to the edge and after a big drop, this tore the lexan at the weak point. The new version has more overall material to increase strength.
More Suspension Mount Holes - More options with all the various shocks that exist today, from 3" to 5" shocks

One thing to note, these are not for sale, I do not have a vendor star, and am not trying to post this as a "this is something you can buy" thread. If I were to ever deem this something I'd want to market, I'd buy a vendor star, and post an appropriate link. Just because I'm not selling it doesn't mean you can, this is my design and protected under prior art copyright law.

There is one more chassis like this that I had cut for my friend, once we get his built up, there will be another thread for his, and how he sets it up. I'll be at a local competition tomorrow and we'll see how it does on the rocks.

I like the look! Should do well, nice and low."thumbsup"

Looks good... but what's up with the blankie on top of the battery?

good eye, the blankie helps support the lipo in a fall. I'm going to try and find a better way to do this though... Ideas?

Foam weatherstrip...comes in different thickness and has adhesive on the back.

Just peel and stick, and a roll of it is cheap.

I like the looks of it. It's funny...I have 4 empty cans of Monster that I keep around just in case I want to make something like this!

I saw a chassis similar to this so if you see somebody building something similar, don't feel that you've been ripped-off.

From what I've seen, these types of chassis have to use spacers from the main chassis to make a legal width body and I remember seeing 2 of them being teched at our last comp.

That would look sweet in carbon fiber!

How did the comp go?

Oh yeah, I might even have some laying around somewhere...

There's a few other bodiless tvp designs out there, most are one piece plates, there's the new rockshow which is kinda like this.

I think mine is the only one that actually looks like a truck or buggy, the other styles look kind of odd.

Rules state the overall width needs to be 3", I'm at 3.5, so I'm fine there.

I know, I may talk to the dragonplate guys and see how much a CF version would be. I like the lexan though because you can paint it any color you would paint a body.

Heading there in an hour, so we'll see.

nice looking rig you got there

Thanks!

Just got back from the comp today with it, the chassis did well, but I made a few dumb mistakes with it. Lack of drag brake and dig also helped score me a few gates and an OB on the first course. Flipping over from being turtled I gunned the throttle and shot out of bounds on the second course. On the third course I got a 10, first ever finish for me. I would have goose egged if I had drag brake and didn't hit the last gate.

I'm going to work on getting my homemade dig going... Until I can afford a real dig.

thanks!

Working on the dig right now, I need to go and get a set screw to get the hex to seat and make a 4mm spacer then figure out servo linkage, and then I'll be good to go... Hopefully.

I'll post pics of the dig later.

very nice very nice i am envious

Dig Pics!
 

Ok, got the dig together, still need to get the servo mounted and the linkage made.

Here's pics and a little explanation of each:

http://img.photobucket.com/albums/v2...e/S5002293.jpg
OK, this is all the parts ready for grease...

Description of parts from left to right:
http://img.photobucket.com/albums/v2...e/S5002287.jpg
AX10 Transmission, stock gears, stock output - M3x40mm Phillips head machine screw on far side, stock AX10 transmission screw flipped around on near side - stock ax10 grey links cut to size, and re-tapped with M3 thread - 12MM wheel hex with M3 set screw from MRC on output - 5mm aluminum tubing, with 12MM MRC wheel hex and M3x8MM set screw (tapped into tubing) with other end ground down for the yoke.

http://img.photobucket.com/albums/v2...e/S5002289.jpg
12MM socket cut down to size with large washer brazed to it - (top) lexan cut shift plates with a traxxas rod end and M3 phillips head screw - 5x8x2.5 bushing (x2) - 5x8x2.5 ball bearing (x2)

http://img.photobucket.com/albums/v2...e/S5002291.jpg
12MM steel nut brazed to 18 gauge steel plate, cut to size - (top) M3x10mm button head screws - Shortened stock driveshaft

Here's everything all greased up and installed:
http://img.photobucket.com/albums/v2...e/S5002297.jpg

http://img.photobucket.com/albums/v2...e/S5002307.jpg
Dig in locked rear position

http://img.photobucket.com/albums/v2...e/S5002298.jpg

http://img.photobucket.com/albums/v2...e/S5002304.jpg
Rear Freewheel

http://img.photobucket.com/albums/v2...e/S5002300.jpg

http://img.photobucket.com/albums/v2...e/S5002303.jpg
4WD

If I were to do this again, I'd think having a lathe and a better torch would have made this a lot easier. So someone out there that has access to a machine shop and can braze can make their own dig for pretty damn cheap (I lost track of cost because some items were part of a package, some I already had, etc.)

When I get the servo figured out, I will post more pics of how it works. I tested it with manually shifting the dig, and it seems to work well. This design requires no torque to keep the dig in each position. Also, since I used the 12 notch socket, it only needs to rotate 30 degrees to get it to line up.

Update coming soon!

Nice work!

I have done the driveshaft dig back in the TLT days.

It was a lot easier than your tranny dig but yours should be better.

I would try to get the dig behind the disconnect and run the are arm straight up and down as opposed to parrallel.

Your servo will be laying on it's side and the movement will probably be smoother.

This is my black widow, but shows the orientation I'm talking about:

http://img.villagephotos.com/p/2002-...0604090734.jpg

I was planning on running the servo vertical with the servo arm on top, but I think I get what you are saying... something like this:

http://img.photobucket.com/albums/v2...shiftdiffs.jpg

The left shows what I think you are talking about, having it straight up and down vs the way I have it (the diagram on the right)

I'm going to try it out this way and see how smooth it is, and if it binds a lot, I will try it the other way... thanks for the advice.

As long as it fits and works, right?

The dig looks sweet man"thumbsup" You coming to finals next weekend?

Wow, a homemade eritex HRD3.1 with 12 point engagemnt! Very kool"thumbsup"

I saw this rig yesterday, real cool rig, thought out with a purpose! Good to see people out there that can build a rig and have fun!!

Keep up the good work!! "thumbsup"

I'm having some issues with my dig now. It works ok when I manually shift it, but once the servo is involved, it binds.
I think it all boils down to not being able to keep the collar straight while shifting.
I'm going to try something tonight to see if I can achieve this without too much modification...
If I can't get it to work tonight, I'll probably end up buying one... likely the eritex (when they get back in stock) but the price of the HR anf FT digs are tempting...
oh, and I also broke an epa pot on my tx while I was trying to set it all up, good thing I bought spares. I think I didn't drill the hole large enough, so it needed excessive force to turn it and ended up breaking.

Ok, got the dig working, after some massaging, and getting something to help keep it all centered. It still binds every now and then, but shifting it back and forth will usually solve the issue. I'll post some pics and vids tomorrow of the dig working.

I'm tired, so I will update on how I did it tomorrow.

Got the dig working, here's a video:

http://www.youtube.com/watch?v=pi2vqimkYMU

I took a tube of a large enough diameter to slide over the standoffs without too much motion to attach to the shift plates, sanded a little here and there, and made a new dig shaft so that everything stays centered better.
I mounted the servo to a lexan plate which is mounted to the chassis standoffs.

It will still bind maybe 1 out of 15 times when shifting from dig to 4WD. I'll get to test it on real rocks hopefully this weekend.

I'll still probably save my pennies to get a "real" dig, but this should get me by until then.