Budget RC Bomber kit build

[Jim85IROC]

In keeping with the theme of my Youtube channel (Budget RC), my focus is mainly on building a crawler that out performs its price in as many ways as possible. This build will also serve as a measuring stick of sorts for some lower priced builds that I have planned.

So, on to the build. I started with the Bomber kit because I felt that it offered a lot more bang for the buck than the RTR. For Electronics I chose parts that I already had on hand, with the exception of the servo, where I decided to splurge a bit (more on that later). The motor is a 13.5t Trackstar sensored 540. The ESC is a 120a X-Car. For the radio, I'm using a Radiolink RG3S. Total electronics investment (minus servo) is under $100.

Since servos are under so much stress in a crawler, I felt that my money was best spent here as opposed to the other electronics. Here I decided on the Promodeler 470, with the Castle BEC set to 8.4v. On my cheaper rigs I plan to experiment with cheaper servos, but I wanted something solid in this truck to serve as a benchmark.

That said, here is the truck so far:


Another thing that I wanted to do was give the truck a high end look without spending a fortune. This also meant trying some new techniques on the body. I can paint up a pretty nice body, but I don't have the time or the patience to go crazy with a wild paint design. I also don't want to put so much effort into the body that I'm afraid to bang it up on the rocks. So, since I've been dying to do a Kryptek pattern on an RC, I decided to buy some vinyl wrap material that uses the Kryptek pattern. To give it a little more flair, I chose two wraps that compliment each other nicely. Since they both use the exact same underlying pattern, if I cut them carefully, I can maintain a continuous pattern theough the color changes. The result should be a high end look with minimal cost, and a lot less effort than painting. Win-win!

Here are the vinyl sections that I cut. I cut each panel section out of the same area on both colors so that I can have the same pattern on both.


For my base, I painted all of the panels black. Here is the hood:


And here is the hood with the vinyl:


I think this idea might just work! I decided to keep going and did the roof. Here are the two panels on the body:


I want to get a bit more involved with the door panels. My plan for those is to use an angled pattern similar to the Bomber kit decals, but with my own twist, and obviously by using the vinyl. Hopefully I come up with a nice design. Combined with my detailed interior, I think this Bomber is going to end up looking like a high end rig!

So far I'm optimistic that this Bomber is going to be a great looking, great performing rig for a somewhat modest investment.

[Jboucher]

How did you paint the interior?
I can't find a good guide for beginner. I was about to just dump liquid mask on it and paint from the outside by cutting out the parts and re-masking, etc

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[Jim85IROC]

I painted it black from the back, then cut the outer protective layer for the people and painted them gray. After that I sprayed the outside with matte clear, then applied the decals. The helmets were done in silver, then orange candy, then I painted the goggles with black model paint (with a brush) and did the goggle bands in gray model paint with a brush.

[Jboucher]

Never thought about using the outer film as a paint mask!
You just saved me a lot of time.

I can do my white drivers easily now and detail them with paint pens or brush.

Thank you!

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[Corbet]

Where did you get the vinyl?

[Jim85IROC]

Originally Posted by Corbet

Where did you get the vinyl?

Ebay.

[Corbet]

Thanks, found it. They don't use "Kryptek" in the description, so my initial search did not locate it.

[Jim85IROC]

Yeah, I'm sure they didn't want to pay the licensing fees.

[E. Bryant]

Originally Posted by Jim85IROC

I painted it black from the back, then cut the outer protective layer for the people and painted them gray. After that I sprayed the outside with matte clear, then applied the decals.

That is an awesome idea, and one that I am totally going to borrow for a couple of upcoming builds. Thanks for sharing!

[Jim85IROC]

I'm kind of shocked that the simple act of using the protective cover on the lexan as a paint mask is the part of this build that's getting the most attention. I thought everybody did it that way. I started doing this to paint the truck beds and the detail around the windows on my basher vehicles, and just carried it through here.

But either way, I'm glad you guys are finding something I'm doing useful!

[Jboucher]

Oh dont worry, the entire build is awesome, it's just mindblowing that most paint guides out there never mention the outer film...
I was going to mess with liquid mask and tons of tape

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[Jim85IROC]

I don’t have a lot of progress to report, but today I made an extension piece to attach to the top of the receiver box. This let me mount the ESC out of the way of the battery tray, and leave room for the BEC in front of it. I also wired up a y-adapter for the servo to get power from the BEC and signal from the receiver. Hopefully tomorrow I can program the esc, then attach the body to the chassis. Then I just need to finish the vinyl on the side panels. We're going to New Hampshire on Thursday, so I'd like to try to have it done by then.

[Jim85IROC]

Yesterday I had a little time to work on the Bomber, and I made some good progress. I programmed the ESC, made my y-cable for the servo, and made a kydex plate that I mounted to the top of the receiver box. This plate gave me enough room to mount the ESC back far enough not to interfere with the battery tray, as well as the BEC and the mess of wiring I've accumulated. All in all, I think it looks pretty tidy considering how much wiring there is!



Body and chassis are mated! I have a bad feeling it'll come back apart 50 times over the next few weeks, but at least it's together for now.



All that's left now is to put the wheels on, give it a shakedown run, and do the decals for the side panels.

[TAMELESSTGR]

I'll be following this one as I am eager to get into a Bomber!

[Jim85IROC]

Well that excitement was short lived. I just let the smoke out of the motor and maybe the esc. . It worked fine before I mated the body to the chassis. I reprogrammed the esc for firward/reverse, 100% drag brake & adjusted a couple other things. I just powered it back on, watched the servo glitch hard left (or right - not sure) then watched smoke pour out of the chassis. After I unplugged I looked and could see the motor smoking and it got hot enough for one of the motor wires to come unsoldered.

The motor never even turned. WTF?

[Jim85IROC]

Hmm... I had the neutral band set to narrow. I wonder if that combined with the drag brake could have caused an issue.

[soze]

Nice, I hope to start a Bomber in the near future.

[Jim85IROC]

Last night I spent my time troubleshooting my burnt up motor. I confirmed that it was wired correctly. I resoldered the melted lead on. The motor was erratic and there was a lot of glitching in the servo. I swapped in a 17t motor, and still had glitching and erratic behavior. I swapped the ESC and things started looking up. I reprogrammed the esc, put the neutral band back to "normal" as a precaution, held my breath, and plugged in the sensor cable after validating everything without it. Everything seems to be working now.

That said, I don't think I'll be keeping this motor/esc combo for long. It's a 17.5t Trackstar 2 pole sensored motor and an X-CAR 120A esc. The minimum speed of the motor seems a bit high, and the esc really doesn't like transitioning between fwd & reverse. Anytime you transition, the startups are at a much higher rpm and makes the vehicle jump. I definitely need something with more low speed resolution.

[JatoTheRipper]

Originally Posted by Jim85IROC

Last night I spent my time troubleshooting my burnt up motor. I confirmed that it was wired correctly. I resoldered the melted lead on. The motor was erratic and there was a lot of glitching in the servo. I swapped in a 17t motor, and still had glitching and erratic behavior. I swapped the ESC and things started looking up. I reprogrammed the esc, put the neutral band back to "normal" as a precaution, held my breath, and plugged in the sensor cable after validating everything without it. Everything seems to be working now.

That said, I don't think I'll be keeping this motor/esc combo for long. It's a 17.5t Trackstar 2 pole sensored motor and an X-CAR 120A esc. The minimum speed of the motor seems a bit high, and the esc really doesn't like transitioning between fwd & reverse. Anytime you transition, the startups are at a much higher rpm and makes the vehicle jump. I definitely need something with more low speed resolution.

That ESC is a clone of a HobbyWing item. HobbyWing isn't the best at FWD to REV transitions required in crawling. But in my short course truck it's an awesome ESC. And the HobbyKing motors are awesome in 2-pole applications. Not so good for a Bomber.

I'd highly recommend the Castle Mamba X ESC for the Bomber if you can break your budget! I can stress enough how much the ability to toggle the drag brake on and off via the Auxiliary Wire is meant for vehicles like the Bomber!

[Jim85IROC]

I'm thinking about the Mamba X and the blue 4 pole Castle can. I'm going to drive this 17.5t for a while first to help me figure out what KV I want in my next motor. Of course, to accurately gauge that, I'm going to need to try it on 3S too, and none of my 3S packs fit into my Bomber battery tray. :(