Few questions from a Capra noob

[Ty89m]

Hey all,


I'm new to the surface hobby, though been flying RC heli's (and some planks) for about 11 years now, so reasonably well versed in the basics. That said, I've now acquired (and built) the SCX10 III and the TRX-4 kits, and seem to have caught the bug! I've got the Capra kit sitting here ready to build as well, and wanted to run through my electronics and see if I'm on right track...


First off, I've got more reading to do when it comes to brushed motors and crawler gearing, as my experience is exclusively brushless thus far. The Capra is the first kit where I'm using my own selection of electronics (I'm using the same electronics in my SCX10 that came in the RTR version for now) and following some other's footsteps I've opted to go with the Holmes 500V3 servo, Hobbywing 1080, and Holmes Crawlmaster Sport 16T. I also picked up a Reedy Radon in 16T as well, may use that in a different build.



I grabbed an 11T pinion for the Capra as well, as it seems stock pinion is bit much at 14T for these builds. Does that seem appropriate? Any great resources on understanding crawler motors and gearing? Like I said, I'm used to calculating headspeed on heli's with a single main gear and pinion, as well as kv and Lipo cell count, so this is all new to me...



That said, I would like to try a brushless system (likely a Spektrum as I like the telemetry and have a DX5 Pro) but would need to figure out the ins/outs of gearing to make a proper selection on kv rating etc.


I'm running 3S on all three trucks, so with that in mind, is my selection appropriate for a "budget" esc/motor setup on the Capra?



Appreciate any and all input, and if someone has a great resource that could help me better understand cralwer specific brushed/brushless motors I'd really appreciate it - as I'd imagine I'll start playing around with brushless setups sooner rather than later, for now I just wanted to get something that would get me started!


Anyway, having a blast toying with these trucks thus far, it's refreshing to have something that moves at a slower pace as opposed to a 700 size heli that could potentially lob my head clean off if I'm not careful ;-)

Edit - here's a motor I'm interested in https://beachrc.com/spektrum-firma-2800kv-brushless-sensored-crawler-motor/
Not sure it'll fit, as it seems it's a bit limited. Length is listed as 58mm, and I've seen mention of 53 being about max, though I'm not sure if that's just the can length, or can + shaft etc. Worst case, I'll could toss it in the SCX10.3 instead if I ran into issues. Seems 2800kv would be suitable for either Capra or SCX. Thoughts?

 

[DrIsotope]

The Capra's gearing is pretty high-- I run a 35T in mine, and still opt for an 11T pinion. The 5-slot Crawlmaster 16T is about the equivalent of a 27T 3-slot motor (something like the equivalent of 1700-1800kv) so it should be okay, but you could go for even higher turns, really.

I've never been happy with any of the sealed can motors, they never seem to make the same torque (and therefore the drag brake is kinda weak) as a rebuildable-can motor of similar turn. The HH Torquemaster Expert is excellent, as is the Tekin HD series. Yeah, both of those motors are around 50 bucks, but there's a world of difference in performance. And you have more than one crawler already (as everyone should) so when you upgrade to brushless, you can "hand down" a nice motor to one of the other rigs.

Speaking of the brushless, 2800kv is too high for the Capra gear reduction, IMO. I'd be looking at something 1800kv or lower. Spektrum does have that exact motor in 1400kv. As to the clearance... I can't say. I upgraded to the Spare Time Hobbies flat skid almost immediately so I could run a full-size servo for the dig. Cheaper than shelling out for a Reefs servo (whatever you do, don't install a Spektrum sx107.). Of course, if you're just building with the dig locked out, ignore all of the stuff about the dig. 8)

If it's within your budget to consider, 4WS on the Capra is amaaaaazzzing. No climbing line is out of the question.

 

[Ty89m]

Really appreciate the input! I'm going to grab either the reefs or a Torque Servo to use as dig function, and now I'm checking out that 3d printed skid you mentioned. Was going to run SSD mounts, but that looks like a good option as well. If I'm reading the description correctly, it seems to solve the motor length issue by removing a link riser (not sure what that is, as haven't started build yet)?


Wondering if going straight to brushless is the right call... hmm, regardless, I'm checking out the rebuildable Tekin and HH motors, happy to spend $50 for a better motor. I'm coming from a world where it's easy to spend $300 on a motor for a larger heli - this is nice change of pace

Edit: Thanks for the heads-up on the 3d printed skid/servo mount, grabbed that as it seems it'll help with future motor fitment issues.

 

[DrIsotope]

The STH skid also means you can run ANY servo, which is great. I don't use a saver on it, I just set the endpoints before physically attaching the servo horn to the dig. I'm using an ancient Airtronics 94851-- it's not fast, but it's more than strong enough to work a dig unit. Never gets bound up.
Oh, and it this pic you can see how much clearance there is behind a 540 can with the STH skid. Plenty. And there's that sealed can 5-slot that absolutely did not tickle my fancy.

 

[OSRC]

The brushed/brushless conversation is one where you'll get all kinds of opinions..., there're no real right answer. It's what works best for you and your budget. Your combo is excellent, I wouldn't change a thing.

I've experimented with brushless here and there, and just keep coming back to brushed. Far more cost effective, more than enough power when needed, and excellent low speed control. Pretty much all of my rigs now run a 1080 and a Holmes motor of some kind, Crawlmaster or Trailmaster. The former seems to have better power and brake, and the latter has better slow speed control in my experience. I'm running a 5 slot 16t/2S in my Capra (Hackmoto IIRC as it was what was in stock when I built it) Very smooth, though it's a bit lacking in the punch department. Doesn't hold the rig back though, it gets where it needs to go.

The 11t pinion is a must imo. I'm debating a 3 gear trans swap in mine just so I can gear down a bit further. I like to drive slow and technical, and the trans is just geared too high for my tastes. That's where the lack of punch is coming from more than the 5 slot motor....

 

[Ty89m]

Appreciate the replies as well as the photos! That gives me a good idea what I'm working with. Nice to have the ability to run whichever servo on dig that I like, I'll see how the cheap little Torq servo works, and go from there. I'll have to check out the 4 wheel steering at some point as well.


I ordered two new Spektrum ESC's along with a 2100kv motor and 2800kv motor, so I can toy around with brushless, though these are essentially the new Axe R2 tweaked for Spektrum, so likely won't fit well in the Capra, and even 2100 may be a bit much - that said, I'll toss them into the SCX10.3 and TRX-4 as a test bed of sorts and run the Firma 4-amp (or my HW 1080, think they're essentially the same) and HH motor in the Capra for now. Also opted to grab a set of SSD and Desert Lizard 90mm shocks for the Capra, lots of goodies to toy around with.



Too much fun, and plenty of great places to go here in Montana "thumbsup"

 

[WHITE-TRASH]

I run a 2700 kv Holmes on 3s in one capra and a tekin roc 2300 on 4s in another.

The 2700 on 3s is solid, crawls really well and has plenty of pep to jump gaps or get ignorant as I wish. The other capra has 4 wheel steering and a titanium chassis so it's a bit of a different animal being barely over 6 lbs but it flat rips. Still crawls well but it has more top end than needed so I'm never left wanting more

 

[Ty89m]

Got this bad body build, managed to get a mini servo installed for dig and running a Firma 60/540T Brushless setup. Works great! Thanks for all the help!