Budget RC Bomber kit build

[JatoTheRipper]

I'd get the Mamba X and pass on the Castle can. It's a good budget start, but there are much better motors for the Bomber. My personal favorite is the Tekin ROC412 in the 3100kV flavor. I also have the Holmes Puller Pro 3500kV and that's too fast for me. I use my Bomber to trail and crawl.

[Jim85IROC]

What pulled me toward the Castle motor (aside from being 1/2 the price of the cans you mentioned) is that it claims to have a startup speed that's 40% of the Tekin. That seems pretty impressive to me.

[JatoTheRipper]

Originally Posted by Jim85IROC

What pulled me toward the Castle motor (aside from being 1/2 the price of the cans you mentioned) is that it claims to have a startup speed that's 40% of the Tekin. That seems pretty impressive to me.

What's 40% of virtually nothing?

[DukeMinnix]

Originally Posted by Jim85IROC

What pulled me toward the Castle motor (aside from being 1/2 the price of the cans you mentioned) is that it claims to have a startup speed that's 40% of the Tekin. That seems pretty impressive to me.

You can tune your esc to start as slow as you can, I played with my castle link and different settings on day. You can literally have it start as a snail. Roc412 fyi

[Jim85IROC]

Drove the Bomber today. When there's an obstacle that strains the throttle, the servo glitches. It doesn't take much throttle strain either. I need to tie the servo ground back to the receiver to see if that helps.

I also had a rear axle bearing and axle slide out of the housing. I couldn't get the bearings to fit in the outer axle extensions so I clearanced them, but I guess I over did it. I'll need to get new ones, but because I want the truck for my vacation this weekend, I ran a bead of plastic epoxy around them to build them up. Hopefully it holds up!

[84yoda]

Yes you need that ground, otherwise it'll cause glitching like you have. Does your y cable for bec, servo to rx look like a holmes rx bypass? If not, make one like that and it'll be glitch free.

[Jim85IROC]

Originally Posted by 84yoda

Yes you need that ground, otherwise it'll cause glitching like you have. Does your y cable for bec, servo to rx look like a holmes rx bypass? If not, make one like that and it'll be glitch free.

No, mine only has the ground between the servo and the BEC. I'll have to add the other ground.

[Jim85IROC]

I had a quick shakedown run on Wednesday and had a couple problems. I have a twitchy servo, most likely because I only ran the ground to the BEC and not the receiver too, and I had a bearing come out of the rearaxle lockout because I can't follow directions and ground the bearing lip away because I thought the bearing went on after the lockout. I ordered new ones, but in the meantime I used some plastic epoxy to fix these. Hopefully they survive the weekend, because there's no rc shop for about 75 miles.

Anyway, the side panels aren't wrapped yet, but overall I'm pretty happy with how it looks. The blue shocks don't bother me enough to replace them yet.

[DukeMinnix]

your body panels are beautiful work.

[JatoTheRipper]

It looks great! I think the all-black side panels are boring and don't fit the theme of your otherwise awesome rig. Are you going to put anything on the side panels?

[Jim85IROC]

Yeah, I'm going to wrap them, but I ran out of time before vacation. Hopefully next week I can do it

[Jim85IROC]

I had 5 minutes to use the Bomber today, but got bored because the terrain here isn't challenging, and I don't have time to take it somewhere else. In the few minutes I used it, I made some observations. The Axial foams are too soft, the sway bar is too stiff, and I'm happier with this motor & esc than I expected. I'm only running 2s right now, and although I want more top end, the low end is more controllable than I expected.

I want to try 3s first, but based on how it goes with the 2250kv 17.5, I think something in the 2800kv range would be ideal. Maybe I'll feel differently after I try 3s.

[Jim85IROC]

So after a whopping 5 minutes with the Bomber, I decided to throw more parts at it.

I really want this to be a 3S rig, and not a 2S rig. The problem is, those X-Car ESCs don't really have a good reputation with 3S, and considering that one of them already burned up my 13.5 motor, I decided it was time to upgrade. I picked up the Castle Mamba X ESC, and for good measure, I also picked up the Castle 1406 2850kv sensored motor. If I can tolerate removing all the screws to separate the body from the chassis more than once, I'd like to try the current 17.5 with the Castle ESC before I install the new motor to see how that combo works.

Hopefully with this ESC I'll be able to eliminate my external BEC, but first I need to make sure that my receiver can survive at a higher voltage.

This "budget" rig has officially gone over the $700 mark, and I've only driven it for 5 minutes. It's funny how this snowballs.

[JatoTheRipper]

Great choice on the ESC.

I'm not sure why you're set on 3S. 3S destroys parts and 2S can more than do the job with the correct motor and gearing.

[Jim85IROC]

I may not always run 3S, but I want the capability for those times where more wheel speed is desired. I've upgraded some of my bashers to 3S, and I like it. I have more power, I run cooler, and my runtimes are vastly improved. It also gives me the ability to easily slow my rigs down by going back down to 2S. I want some of those same benefits here. I may find that I spend most of my time on 2S, but I still want the option for those times when I feel it would be beneficial.

The 17.5t motor on 2S doesn't have enough top end for me. This 2850kv motor might, but even if it does, it gives me the ability to gear it down for more low speed resolution, and then I can still stuff the 3S in for when I want more wheel speed.

[JatoTheRipper]

Not to hijack your thread, but I want to show you what my Bomber does on 2S with a Castle MMX ESC and a Holmes Puller Pro 3500kV motor. This video shows me doing a one-handled blip of the throttle to climb this rock wall. This is not full throttle. I think it has too much top speed for most sections of the trail even on 2S. On 3S it's basher speed, but the Bomber can't handle that and it will constantly roll over when turning.

I prefer the Tekin ROC412 3100kV that I had in the Bomber. It has better crawling/trailing speed. I'm just too lazy to remove all the screws to change the motor.

2850kV might be a good start for you, but it might leave you wanting for more on 3S.

[soze]

Originally Posted by JatoTheRipper

Great choice on the ESC.

I'm not sure why you're set on 3S. 3S destroys parts and 2S can more than do the job with the correct motor and gearing.

Just got a Bomber, and thanks for your confirmation on 2S. All of my batteries are 2S so I haven't joined the 3S party yet.

What gearing are you running in the bomber? Stock?

[Jboucher]

If you go 3s you just need to use a 10-11t pinion with 68t spur.

Holmes said it himself : Volt Up Gear Down.

Sent from my Nexus 6 using Tapatalk

[JatoTheRipper]

Originally Posted by soze

Just got a Bomber, and thanks for your confirmation on 2S. All of my batteries are 2S so I haven't joined the 3S party yet.

What gearing are you running in the bomber? Stock?

Yes, I'm on stock gearing.

[Jim85IROC]

Right now with the 17.5 I'm using the stock spur with a 10t pinion. I geared the 17.5 down a bit primarily because the low speed control with the current esc & 2-pole motor isn't quite where I want it, and gearing down helps with that issue. I'm debating swapping the drive & driven gears in the trans while I have this apart to gear it down a bit more, especially now that I'm upping the KV so much.

I think that what I'll wind up doing is to swap the trans gears, then go back to the 12t pinion with the new motor. This should put me roughly where I'd be with the "stock" trans gearing and a 12t, but still give me a little bit more room to gear down if necessary.