GOM Rx/ESC placement question
 

Hey all, I'm building a GOM kit. This is my first kit, and my prior experience with RC is exclusively installing mechanical upgrades on a RTR Losi Rock Rey; I've never installed electronics before.

I'm not clear how to interpret the directions about installing the ESC and receiver. I'm using a Mamba X and Futaba R203GF.

According to the illustration in the directions (step 48) the receiver fits into a box, and the ESC goes directly over it. There are no screws; instead, the designer of the GOM seems to expect that both the ESC and the receiver have some sort of adhesive tape preinstalled that will fix them to the correct spot on the chassis.

My ESC and receiver didn't come with any sort of adhesive.

Moreover, while the receiver fits pretty snugly into the GOM's box, the servo/ESC wires stick up so far that it seems like the wire would have to bend at a 90 degree angle to fit into the box. Doing that seems like it would damage the wires.

Does anyone have any pointers on the correct way to install these components?

Thanks for reading.

Re: GOM Rx/ESC placement question
 

install it where it fits "thumbsup"

I have a smaller ESC and installed it on its side next to the receiver box, which i think I just left the top off of. I also used a shorty battery which leaves a bunch of space at the back of the battery tray location, I have my receiver installed there.

Oh and my favorite way to mount electronics is with M3 dual lock instead of 2 sided tape/servo tape. Its great because you can pull things loose to reposition them and you dont have to clean off servo tape every time you do so. It also holds stuff very firmly.

Re: GOM Rx/ESC placement question
 

For my build I used an Futaba R204GF-E, which is almost the same as your receiver but no antenna wire. Its definitely a tight fit in the receiver box, and the wires definitely are almost touching the top of box when closed, and definitely cannot fit extra wire in that box, it gets bundled and tired up above the box behind ESC. I tried to use velcro to mount the receiver but it was too tall in the box and caused pressure on wires, so I had to use double-sided tape. It would not fit vertically either. I also had to modify, made the wire hole larger by about 50%, on the box to allow more space for wires to come out of the box as i have 4 connectors plugged into it.

For the ESC, the Mamba X is pretty large, I have a new one, but havent tried to install yet in the GOM, but i know it will be a very tight fit. Im still using a Hobbywing 1080, which is double sided tape to top of receiver box and fits fine. In my build thread (
http://www.rccrawler.com/forum/g-mad...savagegom.html )
I have a pic of when I was installing a new motor, and the ESC you can barely see behind the motor wires. I dont have a pic of my receiver in the box currently.

I havent really had any problems with this type of mounting of receiver or ESC in many years, and used it in over 12x RCs, from 1/5, 1/8, and 1/10. More questions let us know.

Re: GOM Rx/ESC placement question
 

Thanks for the replies, this is super helpful.

Sounds like the thing to do is to leave the top of the radio box off. When I can get some double sided tape I’ll try this out.

My understanding is that the futaba receiver isn’t waterproof, so it seems like this will leave it a bit exposed since there’s no side panel to protect the electronics from splashes from the tire.

Just curious, did you consider drilling holes in the top of the receiver box to let the cords out? I don’t know the first thing about drilling plastic but it seems like that would be easier to waterproof than the exposed receiver.

Re: GOM Rx/ESC placement question
 

You can use conformal coating to waterproof your receiver. https://www.rpphobby.com/product_p/hh-182100001.htm
You'll need to pull the case off of the receiver so you can coat the circuit board, avoiding coating the 3 pin headers (where things plug in).


You can also just avoid water, most people do and those that dont have to tear down their RC's frequently to get the water out of the tires, axles and tranny. Water may be fun but it brings with it lots of extra maintenance.


If my tires aren't vented I dont mind running through a little water as long as its not axle deep. Even then I dont go splashing through.

Re: GOM Rx/ESC placement question
 

Do you have access to a 3d printer? I made an extended/taller lid for the rx box to fit a Spektrum receiver in. If you don't own one, check your local library. I can post the stl.

The rx goes in the box, the esc sticks on top. Lots of ESCs do have the tape pre-applied or in box. This isn't a unique design to the GOM. If your's doesnt have it, grab some emblem tape from a big box store or hobby or auto shop.

I've seen a few others with the rx or esc in the rear or cabin.

Re: GOM Rx/ESC placement question
 

Oh, I'd love to see that STL. I don't have a printer, but a friend does.

RE avoiding water, unfortunately all the good crawling spots near me are either near or in rocky streams. I had actually bought everything else in the GOM to be waterproof, but I forgot to check the receiver.

Servo tape has worked pretty well so far to keep the ESC and receiver in place for the few runs I've done with the GOM so far, thanks to everybody who explained that you can just buy any old tape. I almost got the 3M tape but I had to order some other parts anyway so servo tape seemed easier.

There's two big issues I still have with the GOM before I can call it "done."

Firstly, the screw connecting the steering rod to the metal servo horn I bought doesn't want to stay in place, even with a bit of blue loctite applied. I've tried using a nylock nut instead of the normal one they suggest to use with the plastic servo horn, which quickly came off as the screw unscrewed itself.

And secondly, my battery is too tall, and catches on the roll bar as I push it in. I still need to experiment with the orientation to see if there's a direction where it's easy to get out without pulling on the battery wires, but I'm a little nervous about how much force is getting applied to the battery even without that factor.

Re: GOM Rx/ESC placement question
 

1. Which servo horn are you using? or post a pic. Is the hole threaded on the servo horn?

Some servos come with cheap quality aluminum horns, or It could be your just using a thin one with very few threads, like this style (https://www.rpphobby.com/product_p/ref-s44.htm) where the metal is just so thin you only have a few threads to hold, im not a big fan of this style and have had a few where the threads stripped out eventually, I try not to use that style much anymore and have swapped most mine with something with more threads to hold, like this style (https://www.rpphobby.com/product_p/ref-s71.htm) see that it has more metal on the end so it can hold on with more threads. It doesn't have to be a Reefs, can use Vanquish, Axial, etc, whatever brand you like really, just the style is important.

On this GOM I am currently still using a thin one and haven't had it come off yet.... but its got loctite and has a few threads above the arm and has been holding just fine with no nut at all. <a href="https://imgur.com/cFaoULb"><img src="https://i.imgur.com/cFaoULbl.jpg" title="source: imgur.com" /></a>

2. About battery, what are you using? And what MAH are you running?

I mostly used 2s or 3s 5000mah batteries since ive had them forever from other truck over the years, this GOM is different than most trucks ive run as you slide the battery inside from the side and thus limited on battery size, im not a big fan of this design, but it is what it is for the cool scale factor of the truck and thus stuff may not be in optimal places and we have to make do with whats provided. So I didnt use the door, Id take the hood off to change battery from under the windshield support bars area, but its a 5000mah so it lasts forever and I normally get bored before its dead and just change at home.

Currently I now use a smaller battery. Recently purchased a 3300mah battery so I can use the door and not have to remove hood every time and keep the 5000s as the spare batteries. This is what I got and I really like how it fits, Gens Ace 3S 45C 3300MAH (https://www.rpphobby.com/product_p/g...3s1p-deans.htm).

Battery door view, these are all with 3s 5000 mah battery
<a href="https://imgur.com/OQHiDDU"><img src="https://i.imgur.com/OQHiDDUl.jpg" title="source: imgur.com" /></a>

Hood open to remove battery very carefully
<a href="https://imgur.com/gI41vkr"><img src="https://i.imgur.com/gI41vkrl.jpg" title="source: imgur.com" /></a>

And a side view to show you my receiver box and esc mounted on top and tons of wires. This is more in response to your previous posts, but you can see the double sided tape here of how I mounted it.
<a href="https://imgur.com/cHjZRB2"><img src="https://i.imgur.com/cHjZRB2l.jpg" title="source: imgur.com" /></a>

Re: GOM Rx/ESC placement question
 

I'll DM you the link for the rx top. (idk what this forum accepts for files/links) It has 9mm of clearance. IIRC the stock is 5mm?

E:
Lid: https://www.thingiverse.com/thing:4582834

Roof: https://www.thingiverse.com/thing:4582862

<blockquote class="imgur-embed-pub" lang="en" data-id="a/LT7dG4t" ><a href="//imgur.com/a/LT7dG4t">gmade gom rx lid</a></blockquote><script async src="//s.imgur.com/min/embed.js" charset="utf-8">

Re: GOM Rx/ESC placement question
 

Thanks for the pictures savage. I’m using an exotek horn which looks like it might be considered “thin”. Tbh I never even considered that there might be servo horns with different thicknesses, I just wanted a clamping servo horn after struggling to get the Losi 23t metal one on and off my rock rey.

For the battery, it’s a 5000mah 3s spektrum model. Vastly taller than what you’re using.

I did find a workaround to using it more easily: if I leave out the seats and the polycarbonate interior they’re connected to, I can fit it in through the window of the truck. Obviously not an ideal solution, but it’ll do till I cave in and get a smaller capacity battery. I want to keep using 3s, since my 2200kv motor is painfully slow, so I’ll probably see if there’s any smaller capacity spektrum batteries that fit the bill. The truck seems to be much more energy efficient than my rey with stock electronics, so the lessened capacity might not be an issue.

And nomudpls, thanks for the STL file!