Custom chassis for a wraith.

Corban_White

Well-Known Member
Location
Payson, AZ
Well, I posted a pic in the "what did you work on today" thread, but @jsudar said I need to post a build thread and revive this sub forum, since it hasn't been posted in for over 2 years. So here goes.

Backstory: About 8-10 years ago (around the time most of you were loosing interest in RC crawlers and getting excited about drones :rofl: ) I picked up a Wraith. I had a bunch of fun with it but wanted it to go fast and crawl. So I spent a bunch of money and put a really nice sensored brushless system in it and a 2 speed transmission. Then it was awesome. Crawled better and would go really fast. But it was hard to control at speed. Super fun with paddles at the dunes though! And it now went fast enough that it broke parts a lot. I also had a Traxxas Summit with a Tekin R8 setup that was awesome everywhere so the wraith kind of just sat with some broken parts. Eventually they both did. Then, about 2 years ago, my 9yo son was asking about the cars, wondering why we never used them. I told him they were both broken but I had the parts, just needed time and motivation to fix them. He asked what he could do so I found a youtube video, sat him down with my ipad, some tools and parts and left. He had to ask for help a couple times, but a short time later everything was up and running again! And so an RC mechanic was born. :D

Now I had a mechanic and a buddy to drive with so they started getting a lot more use. We would take them camping, build jumps out of snow in the front yard, he would drool over cool cars and upgrade parts in the catalogs, etc. Then last spring we were camping outside Goblin Valley and had an absolute blast crawling on the rocks.

IMG_20200505_163544.jpg

IMG_20200505_163600.jpg

It was then that I decided this could be even more fun if both our trucks were the same, or at least the same size and suspension type.
Then we were camping with @benjy and his family (he also has a Wraith) and we ended up setting up a course with (pine)cones and I was hooked.

IMG_20200807_194950.jpg

Came home and listed the Summit and a 1/16 Revo I had picked up on KSL. Then I found a modded wraith on KSL for $200 so I grabbed it for my son. It had a steel chassis, super slow 80t motor, longer shocks that made it really tippy and some other stuff but he was so excited! He got right to work and painted the body panels and attaching the super expo murder spork @jsudar gave him!

IMG_20201005_180814.jpg

My wraith was starting to show some wear so I was looking at getting a new one to swap my drivetrain into but they sell out pretty quick every time they come in stock. Then I found a screaming deal on an almost stock one with super low hours on KSL so I grabbed it and swapped my parts. No pics there. I also grabbed a pack of mini cones from Amazon so we could set up a "real" course :cool::rofl:. So now we have 2 pretty decent Wraiths and a bunch of spare parts. My son got a 55t motor and a sweet little scale winch for Christmas so he was super excited. Then over new years we were down in StG and did some crawling at sand hollow, pioneer park and a park across the street from @benjy's house, where my son was getting a little frustrated because his rig was too top heavy and too low on torque. Which brings us to the build portion of the build thread.
 

Corban_White

Well-Known Member
Location
Payson, AZ
My son and I discussed what he wanted out of a crawler and I started pricing out the tools and supplies we would need. It was going to be a fair amount of money and I wanted him to have some skin in the game. at 11 years old he doesn't have a lot of opportunity to earn money, so we came up with a plan for "indentured servitude" :D. He agreed to 50 hours of hard labor (with some deadlines) in exchange for me bankrolling the project. So, I ordered some tools and materials and we waited. I didn't plan on doing a build thread so I didn't take all the pictures I should have. While we were waiting for parts, we worked on design.The awesome thing about the Wraith is all the suspension and drivetrain are mounted to the skidplate. So we just had to build/design a chassis that would mount to the skidplate, locate the upper shock mounts and hold the electronics. This is the preliminary sketch we came up with:

PXL_20210108_021014220.jpg

Eventually, a bunch of stuff finally showed up in the mail and we learned how to bend brake line and silver solder. After some practice we got started building.

PXL_20210117_022745950.jpg

Those tubes took the better part of a day and 2 "learning opportunities" :rofl: to get right and symmetrical. Next time I have compound bends like that I will make it out of tie wire first. Then we made a steel plate the same size as the wraith skidplate so we could build off of that without melting the plastic.

PXL_20210117_043304154.jpg
Did some soldering, some brazing and a little more bending:

PXL_20210118_183726238.jpg

PXL_20210118_183621989.jpg

PXL_20210118_193008585.jpg

PXL_20210118_193020830.jpg

PXL_20210118_193146480 (1).jpg

PXL_20210118_194256661.jpg

A careful comparison between this picture and the early one will reveal that the front and rear pieces moved in towards the cab due to the heat but we didn't notice until later and we didn't want to re work the tubes that got added in so now the shock mounts will be slightly leaned back/forward from what we had planned. Not too big of a deal, but I wish I had caught it before we added in the bracing tubes.
 

Corban_White

Well-Known Member
Location
Payson, AZ
That brings us to where we are now:

PXL_20210123_020405156.jpg

PXL_20210123_020449673.jpg

PXL_20210123_020458147.jpg

We have planned the placement of the electronics and my son is having a great time building it. The only thing he really doesn't like is "notching" the the tubes with the file. I have been helping him with some of those but other than that it's mostly been him. We are both pretty happy with how it's turning out and excited to see how it goes. I will try and take more pictures to keep this better documented.
 

Marsh99

Lover of all things Toyota
Location
Mantua UT
What kind of tubing are you using?
I have been thinking of building another chassis. I found this website with a bunch of chassis templates.

The last chassis I built I used 3/16 steel rod and mig welded it. It did not look that great and took a lot of die grinding to clean it up. I have been looking into brazing or getting a cheap tig setup.

Looks awesome, great work!
 

Corban_White

Well-Known Member
Location
Payson, AZ
What kind of tubing are you using?
I have been thinking of building another chassis. I found this website with a bunch of chassis templates.

The last chassis I built I used 3/16 steel rod and mig welded it. It did not look that great and took a lot of die grinding to clean it up. I have been looking into brazing or getting a cheap tig setup.

Looks awesome, great work!
I am using 3/16 brake line. Thanks!
 

Corban_White

Well-Known Member
Location
Payson, AZ
For todays update, my son got the last chassis bars in (for now - we may add a few small ones later, not sure yet) and we did a little mock-up.
Without electronics:

PXL_20210126_021552510.jpg

PXL_20210126_021600689.jpg

PXL_20210126_021606592.jpg

PXL_20210126_021623398.jpg


And with electronics:


PXL_20210126_022440682.jpg

PXL_20210126_022447263.jpg

PXL_20210126_022457520.jpg

PXL_20210126_022548003.jpg


These should be pretty close to ride height. Just need to make some mounts for all that stuff and the upper shock mounts and get it all installed. The winch will probably end up upside down under the hood area. We might have a runner by the end of the week!

Also, here is a comparison to the different chassis sizes.

Top is the Integy T2 steel chassis that is came with
Middle is the new custom one
Bottom is a (broken) stock plastic chassis

PXL_20210126_020700529.jpg
 

Corban_White

Well-Known Member
Location
Payson, AZ
Weekend update: It runs!

Making some crawler soup to get the flux off:

PXL_20210129_223305203.jpg

ESC mount in the back and receiver box mount in the front:

PXL_20210129_234145051.jpg

All together:

PXL_20210130_205343345.jpg

PXL_20210130_205413061.jpg

PXL_20210130_205406362.jpg

Only pic I got of the battery holder:

PXL_20210201_145547036.jpg


Testing went really well, except I was trying to do donuts in the dining room and it went cartwheeling down the stairs. One of the roof bars has a slight curve in it and my son is not happy! :rofl:



Now I just need to figure out where to mount this little guy and then it will get stripped down and prepped for paint!

PXL_20210201_145634529.jpg
 

Corban_White

Well-Known Member
Location
Payson, AZ
Got the chassis sandblasted and primered.

PXL_20210204_025220517.jpg

Unfortunately the primer came out of the brand new can looking like bedliner. :(

PXL_20210204_025229245.jpg

Not sure why. When I first saw it (my son was doing the spraying) I thought it was just operator error. I cleaned the tip, shook the can a lot, did some testing, nothing I did made it any better. Oh well, now my son gets to sand. Hopefully on to paint today!
 

Corban_White

Well-Known Member
Location
Payson, AZ
We decided sanding was too much work. It's a rock crawler after all, it's OK if it looks like bedliner!

PXL_20210205_041057661.jpg

PXL_20210205_164437459.jpg

The camera doesn't show the color very well, it's fluorescent hot pink!

And now so is the garage!

PXL_20210205_041044238.jpg

PXL_20210205_042239256.jpg

Got it all built and made some panels out of a flexible cutting board:

PXL_20210207_003146567.jpg

PXL_20210207_003209449.jpg

PXL_20210207_003222746.jpg

PXL_20210207_003304296.jpg

PXL_20210207_003311188.jpg

PXL_20210207_003454499.jpg
 

Corban_White

Well-Known Member
Location
Payson, AZ
So, my son decided he wanted to try 4 wheel steer. I told him the only way to do that was with an airplane (twin stick) controller. (I have since looked into it and found that there a ton of options to do it with a traditional car remote). Anyway, he didn't want to use an airplane controller so we figured it could be done with a Y servo harness and a servo reverser. So, he swapped some parts around and voila! 4WS.

PXL_20210212_224847995.jpg

On Friday we went out to Little Moab and had an absolute blast! It works really really well!

PXL_20210212_224826075.jpg

PXL_20210212_224857252.jpg

PXL_20210212_230549939.jpg

PXL_20210212_233838446.jpg
 

Coco

Well-Known Member
Location
Lehi, UT
Sorry, I don’t know these things, but a Y servo harness would just be a splitter right? So the axles don’t steer independently of an other, but just where one turns, the other always turns equally but opposite?
That is correct. In order to control the rear separately from the front, you would need a 3rd channel, and thus, a 3 channel radio/receiver.
 

Corban_White

Well-Known Member
Location
Payson, AZ
Sorry, I don’t know these things, but a Y servo harness would just be a splitter right? So the axles don’t steer independently of an other, but just where one turns, the other always turns equally but opposite?
Yes, the Y harness is just a splitter. The way the steering is set up, if we just use a Y harness it would steer the same way (crab steering). So we had to put a servo reversing cable (it has a chip that inverts the signal) to make it steer opposite. There are some boards out there that allow you to switch between front steering, rear steering, crab steering and 4 wheel steering with a 2 or 3 position 3rd channel, and some of them even have options to do it with only a 2 channel radio. Then there are nice radios that will so channel mixing, so you can program the rear to do all sorts of cool things. We are trying to keep this on somewhat of a "budget" for the time being. We may move onto some of those other options down the road.
 
Top