New to Building RC: Capra 1.9

[Lowlyslows]

Hey all,

I am very new to building RC cars and I am a bit lost on all the options for electronics. I did some research and followed some videos online and think I have found some options that should work with my build. I'd like to get some opinions on these options before buying.

Building an Axial Capra 1.9

Motor - Holms Hobbies Puller Pro V2 540 Waterproof Sensored Crawler Motor 2700kv

ESC - Castle Creations 1/10 Mamba X Sensored 25.2v WP ESC 8A BEC

Radio - Futaba 4PM 4 Channel 2.4 GHz T-FHSS Radio System w/R304SB Receiver

6-channel Receiver - Futaba R2106GF 2.4 GHz FHSS 6-Channel Micro Receiver
(Only reason I can see using this is to have extra channels down the road but not sure if it will work with the radio being it's only a 4 channel radio)

Steering Servo - Futaba S9177SV S.Bus Programmable Airplane Servo (High Voltage)
(Is this a good option being it's an airplane servo?)

BEC - Castle Creations CCBEC 10A Peak 25V Max Input SBEC

BEC Bypass Adapter - Holmes Hobbies Receiver Bypass Adapter w/Auxiliary Output

Battery - Gens Ace 3s LiHV LiPo Battery 60C w/XT-60 Connector (11.4v/3600mAh)

XT60 Fittings - Maclan XT60 Connectors

Capra 1.9 DIG parts for micro servo - Axial Mounts & Servo Saver Set: Capra 1.9 UTB Dig Transmission

Micro Servo - Power HD TR-4 Micro Waterproof Metal Gear Servo for traxxas TRX-4


Question 1: Do I need a BEC with my selected ESC? Looks like it goes up to 8.0v.

Question 2: The micro server seems to be a hot topic for this build as it calls for the SX107 to enable the Dig option. Two things: 1) It's backordered for who knows how long and 2) People have problems with it but I assume it's because they are not using BECs and burning the servos up or they are using BECs and the servo is just junk. I found a forum that had a reply where a gentleman suggested using the TR-4 Micro servo. Anyone have an opinion on this?

Question 3: What's the programming like for all the electronics? I built several RC helos years ago and it was almost plug and play except for tuning the radio itself.

Anyway, thanks for the help! Looking forward the building the Capra 1.9 and chasing my kids with it!

-Slows

[Greatscott]

1. No. That ESC has an 8amp BEC, which should be plenty for that rig.

2. Get a Reef's micro servo, it will handle higher voltages. The servos burn out because of people running > 6VDC, the Reef's micro servos will handle 7v.

3. The easiest way to program the MambaX is to use the Castle Link with the link software on your computer. You will want to set it up for reverse rotation due to the portals.

[islandlife]

I run the powerhd tr-4 in my capra, at 7.4v. It works well, but it is not a direct bolt in. The mounting holes are slightly off. There is an adapter on thingiverse to make it work if you have a 3d printer. I think people burn up the dig servos by not having the endpoints set correctly.

[twade984]

Originally Posted by Greatscott

The servos burn out because of people running > 6VDC

Not exactly. I burned one up after using the dig function exactly twice, bec set below 6v and end points set properly. I installed a new one, and it burned up 5 minutes into the next run.

That sounds like a great setup though. The mamba x will need to be tuned with castle link (there is a voucher included with the esc for a free castle link USB adapter).

I would recommend the setup outlined here:

https://youtu.be/1r8y_hJjjKU

Steering servo will need to be properly centered, and then end points set with your radio.

Same for dig servo, you will need to set end points for proper operation.

[Lowlyslows]

Originally Posted by Greatscott

1. No. That ESC has an 8amp BEC, which should be plenty for that rig.

2. Get a Reef's micro servo, it will handle higher voltages. The servos burn out because of people running > 6VDC, the Reef's micro servos will handle 7v.

3. The easiest way to program the MambaX is to use the Castle Link with the link software on your computer. You will want to set it up for reverse rotation due to the portals.

Copy all!

Would the SEHREEFS25 be a good option? Is it a direct replacement?

[Lowlyslows]

What do you guys think of the steering servo options?

[Lowlyslows]

Originally Posted by islandlife

I run the powerhd tr-4 in my capra, at 7.4v. It works well, but it is not a direct bolt in. The mounting holes are slightly off. There is an adapter on thingiverse to make it work if you have a 3d printer. I think people burn up the dig servos by not having the endpoints set correctly.

Is this it?

https://www.thingiverse.com/thing:3896942

[twade984]

Originally Posted by Lowlyslows

What do you guys think of the steering servo options?

I don’t have any experience with the futaba, but I know it’s a favorite of Josh, aka Harley Designs

I’ve had great luck with Holmes servos, the shv650 would be a great option, and can be powered directly from the receiver since you would be using a mamba x. My f9 Capra has an shv800 in it.

I also have two protek 370tbl’s which I’m happy with.


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[King Dork]

Lowly, I run a Mamba X in my Capra which would handle damn near any servo, although I’d strongly recommend either a Holmes or AGF direct powered. I run the Holmes 500V3 (no longer available it seems) and it’s plenty strong. I personally think that 2700kv is a bit high for a Capra especially given the transmission ratio but it can definitely work. I run a Holmes Puller Pro 2200 Stubby in mine and it’s got stupid power but is honestly way more wheel speed than I need in my Capra (11 tooth pinion, I absolutely can not fit a 10). Got a Reef’s 99 for the dig on I believe 8.4v from the esc. It’s way overkill but as long as you’re very careful setting endpoints most will work fine. Battery you mentioned is at the absolute max for what will fit the battery tray as long as you don’t need to run ANY extra wiring through the battery tray. I would also strongly recommend doing the pen spring mod with the kit shocks to drop the CG roughly 10mm and mount the front upper shock mounts farthest hole back, and rear upper shock mounts farthest hole forward. This really helped keep the rig planted and still articulate very well. Don’t go crazy adding a crap ton of weight. I added 85g of Treal brass to each of the front portals and it’s awesome (stock springs, 40wt front oil, 50wt rear oil). This is how I set it up when I built it and wouldn’t change anything. FWIW, I run relatively small (5”) 2.2 tires on plastic Proline 2.2 rims. I have tried 1.9 Hyraxes and 1.9 Duratrax Showdowns which both worked well, I just slightly prefer the “small” 2.2s. Good luck!

[islandlife]

Originally Posted by Lowlyslows

Is this it?

https://www.thingiverse.com/thing:3896942

I used this one here when i was using the stock skid
https://www.thingiverse.com/thing:4809914

[Lowlyslows]

Originally Posted by King Dork

Lowly, I run a Mamba X in my Capra which would handle damn near any servo, although I’d strongly recommend either a Holmes or AGF direct powered. I run the Holmes 500V3 (no longer available it seems) and it’s plenty strong. I personally think that 2700kv is a bit high for a Capra especially given the transmission ratio but it can definitely work. I run a Holmes Puller Pro 2200 Stubby in mine and it’s got stupid power but is honestly way more wheel speed than I need in my Capra (11 tooth pinion, I absolutely can not fit a 10). Got a Reef’s 99 for the dig on I believe 8.4v from the esc. It’s way overkill but as long as you’re very careful setting endpoints most will work fine. Battery you mentioned is at the absolute max for what will fit the battery tray as long as you don’t need to run ANY extra wiring through the battery tray. I would also strongly recommend doing the pen spring mod with the kit shocks to drop the CG roughly 10mm and mount the front upper shock mounts farthest hole back, and rear upper shock mounts farthest hole forward. This really helped keep the rig planted and still articulate very well. Don’t go crazy adding a crap ton of weight. I added 85g of Treal brass to each of the front portals and it’s awesome (stock springs, 40wt front oil, 50wt rear oil). This is how I set it up when I built it and wouldn’t change anything. FWIW, I run relatively small (5”) 2.2 tires on plastic Proline 2.2 rims. I have tried 1.9 Hyraxes and 1.9 Duratrax Showdowns which both worked well, I just slightly prefer the “small” 2.2s. Good luck!

Thanks for all the great advice! I’ll change the motor to yours. I’m looking at the Holmes SHV500 LP, thoughts?

Also, when you built yours, does it come with all the grease, oil and thread lock or do I need to buy my own?

What’s the pinion you used? I can’t find a 11t with a 3.175mm bore, just 3mm bored?

Lastly, and this might be lame, what kit would I use to make the headlights work?

[islandlife]

Originally Posted by Lowlyslows

Thanks for all the great advice! I’ll change the motor to yours. I’m looking at the Holmes SHV500 LP, thoughts?

Also, when you built yours, does it come with all the grease, oil and thread lock or do I need to buy my own?

What’s the pinion you used? I can’t find a 11t with a 3.175mm bore, just 3mm bored?

Lastly, and this might be lame, what kit would I use to make the headlights work?

The kit comes with grease and threadlocker etc.

I use a robinson racing pinion:
https://www.amainhobbies.com/robinso...rrp0110/p49529

I found a generic led kit and controller on amazon. Came with 2 5mm white led and 2 3mm red led. I 3d printed a mount for the tailights. The controller for the lights is only needed if you want to be able to turn them off.

https://www.amazon.ca/gp/aw/d/B08FLZ...b_b_asin_title

https://www.amazon.ca/Light-White-De...s%2C164&sr=8-4

[Cyclist]

Definitely no BEC needed with that ESC, it's plenty strong. Direct power servo's are good, but with that ESC you'll have no problem powering and servo you chose. As far as the micro servo goes, I've used that same Power HD TR-4 in my Capra for the past year without issue, and I run it at 7.4v.

[Lowlyslows]

Originally Posted by Cyclist

Definitely no BEC needed with that ESC, it's plenty strong. Direct power servo's are good, but with that ESC you'll have no problem powering and servo you chose. As far as the micro servo goes, I've used that same Power HD TR-4 in my Capra for the past year without issue, and I run it at 7.4v.

How do I power the servo for full power? Do I need an adapter?

[twade984]

Originally Posted by Lowlyslows

How do I power the servo for full power? Do I need an adapter?

Direct power servo typically uses a jst pigtail soldered to the esc side of the battery connector

Non direct power servo will plug into the receiver only


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[Lowlyslows]

Originally Posted by twade984

Direct power servo typically uses a jst pigtail soldered to the esc side of the battery connector

Non direct power servo will plug into the receiver only


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Okay, I’ll have to find a video on this.

Thanks everyone, just ordered everything!

[Lowlyslows]

Originally Posted by twade984

Direct power servo typically uses a jst pigtail soldered to the esc side of the battery connector

Non direct power servo will plug into the receiver only


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Is this what I need?

https://www.amainhobbies.com/dynamit...hoCdpQQAvD_BwE

[twade984]

Originally Posted by Lowlyslows

Is this what I need?

https://www.amainhobbies.com/dynamit...hoCdpQQAvD_BwE

Yes, the shv500lp is a single wire servo, and can be wired into the receiver only, or to the receiver and direct to the battery plug with the included adapter harness. Not sure if it also includes the red jst pigtail that will be soldered to the battery plug.


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[Lowlyslows]

Originally Posted by twade984

Yes, the shv500lp is a single wire servo, and can be wired into the receiver only, or to the receiver and direct to the battery plug with the included adapter harness. Not sure if it also includes the red jst pigtail that will be soldered to the battery plug.


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I ended up getting this servo:

https://www.amainhobbies.com/reefs-r...fs02%2fp873496

Do I still need a JST pigtail?

[islandlife]

Originally Posted by Lowlyslows

I ended up getting this servo:

https://www.amainhobbies.com/reefs-r...fs02%2fp873496

Do I still need a JST pigtail?

Pretty sure that servo will run off your receiver.