Stock mCPx BL with mCPx v2 board and external ESCs

[wadders248]

My mCPx v2 was getting a bit tired and someone on eBay has been selling the mCPx BL minus main board for not much more than the cost of three servos, so I thought I'd give this a try.

The mCPx v2 main board was previously used for a double brushless setup, so I used the existing XP-12a for the main motor, but swapped to a HK-10a for the tail motor and BEC to power the main board and servos.

It is really nice to fly, though the only problem I have is the governing of the main motor. No matter what BLHeli governor setup I try, it doesn't feel like the governor is working properly? I presume the stock motor has six poles and 6700kv? I've never used an inrunner with BLHeli, so if anyone has any ideas that would be great.

The tail is solid and I was going to swap an outrunner, but the stock tail motor has been just fine. Possibly because the servos are running at 5v, they're really quick and strong, not sure how long they'll last.

I would like to keep it stock, so it's quick and cheap to repair, but with the external ESCs I've got more tweaking control!

[wadders248]

I tried the heli outside over the weekend in windy conditions. The stock tail just couldn't cope with backwards or tail down stuff in the wind, so ordered a HP03T 4000kv.

Anyone know where you can get Pulse batteries in the UK?

[Dirtbag]

Similar to my setup but how do you fit the canopy? V2 board is taller than BL board, and barely fits the BL canopy, but you have motor wires on top of it.

[wadders248]

It's definitely compact under the canopy, but not too bad. The tail motor wires are pushing on the canopy, though when the HP03T arrives, I'll solder directly to the ESC, which will save some space and weight. The main motor wires run behind the main board, which meant I had to remove the older tail and main motor connectors from the board to make room.

[wadders248]

New HP30T 4000kv tail motor, Astroid motor mount and 3mm boom in the stock frame. Soldered it to the ESC, it armed just fine, flicked off TH and one of the ESC FETs shoots sparks

[wadders248]

New ESC all soldered and working... not sure why the previous board fet went pop. The HP03t is much better, too windy outside to fly, though it feels really solid and doesn't sound like a nervous wasp!

[Canadian_Jesus]

I wish I had the soldering skills to do all that tinkering. It's all pretty impressive to me!

[wadders248]

Originally Posted by Canadian_Jesus

I wish I had the soldering skills to do all that tinkering. It's all pretty impressive to me!

I only started soldering stuff like this when the mcpx was first released. There's loads of great videos and help. I just use a small Antex iron for this small stuff, with really fine tips for the super tiny things and a bigger flat tip for motor and battery connections. A good third hand tool, with magnifying glass is essential.

[wadders248]

I've been flying quite a bit with the new tail and it's great, not a hint of blow out in fast backwards, or tail-down. I also added a rear swash guide and the Lynx dampeners, which make the head drum-tight. I added the Fusuno canopy purely on looks, it really doesn't help with performance being so heavy!

[mnipjy]

Hello
I'm very interested in your this job.
I'm a MCPX BL user and planning to replace the board with v2 board because of the slow flip and piro rates of stock BL board.
I just wonder if the tail is solid enough during 3D, and body is calm enough without wobble during hovering.
Thanks for your valuable info!

[wadders248]

I've not flown the mCPx BL board, so I'm not sure how it compares. Though I wouldn't expect much more from the v2 board unless you already have a v2 board and prefer this.

The flip and roll rates are ok if you've maxed-out your DRs, but it's very easy to bog the heli with lots of aileron or elevator if you're too heavy with the collective.

None of the micro helis have fast piro rates, due to the fixed pitch tail rotor. The piro speed on mine feels slow, but there's nothing that will improve this.

The only wobble I had was when I added the Lynx dampeners and the v2 board hasn't got any gain adjustment. Whilst flying I didn't notice the wobble, so I just flew it. After around ten packs, the wobble disappeared! I've seen lots of mCPx helis that wobble, but it's generally guys who crash and then expect the heli to fly perfectly afterwards. The more you look after your mCPx, the better it will perform.

For me the stock tail wouldn't hold well enough and as I already had the external ESC, it made sense to use the HP30T 4000kv tail motor. I also use the Plantraco/RRC 65mm Tail Rotor. This combination has never suffered a blow-out!

Originally Posted by mnipjy

Hello
I'm very interested in your this job.
I'm a MCPX BL user and planning to replace the board with v2 board because of the slow flip and piro rates of stock BL board.
I just wonder if the tail is solid enough during 3D, and body is calm enough without wobble during hovering.
Thanks for your valuable info!

[MrTal]

Originally Posted by wadders248

For me the stock tail wouldn't hold well enough and as I already had the external ESC, it made sense to use the HP30T 4000kv tail motor. I also use the Plantraco/RRC 65mm Tail Rotor. This combination has never suffered a blow-out!

Well what about a big fast backwards loop?

I have a stretched mcpx BL with 7000KV hp03T with RRC prop (blheli) and do get it to blow out in fast flown backwards loops.

[JonJet]

Nice build...I wasn't aware that the V2 could be used in place of the BL board...

I'm surprised that it handles the BL motor without issues...the V2 boards are known to be very susceptible to vibrations, so watch for that and cure them

The V1 board was/is a lot better

I have a mCPX BL running BLHeli on the tail with an XP7A ESC...rock solid

[wadders248]

The V2 board is really only controlling the servos, as there's separate ESC's for both main and tail! You need to use the V2 board with the BL servos if you don't want to have to adapt them, though the V1 board was the best I've had!

Originally Posted by JonJet

Nice build...I wasn't aware that the V2 could be used in place of the BL board...

I'm surprised that it handles the BL motor without issues...the V2 boards are known to be very susceptible to vibrations, so watch for that and cure them

The V1 board was/is a lot better

I have a mCPX BL running BLHeli on the tail with an XP7A ESC...rock solid

[wadders248]

The HP03t 4000Kv motor has 12 magnets and is supposed to be a better option on 2s, even though it's spinning slower! I've also been running the latest 14.0 BL Heli version on both boards, which feels more solid.

Originally Posted by MrTal

Well what about a big fast backwards loop?

I have a stretched mcpx BL with 7000KV hp03T with RRC prop (blheli) and do get it to blow out in fast flown backwards loops.

[wadders248]

I've not flown the mcpx for ages, as it's been good flying weather most days for larger helis, but it's raining today. I've swapped back to a stock canopy for weight and also added a Lynx boom support, which stiffens the 3mm boom even more.

I keep telling myself to keep the mcpx cheap, though the frame really does flex, especially around the board mounts. I've got the Astroid frame brace, but I think I'll swap to the RKH frame soon. Then I've got options for the main motor too. I don't want more power, but BL Heli governor doesn't work with the 2 pole motor.

[wadders248]

I couldn't resist any longer, so I've swapped to the RKH frame. I'd forgotten how solid the little carbon frames make the mcpx. I also swapped to the Quantum 8200kv, which is totally bonkers! I've got my DR's and servo travel almost at the max and the motor doesn't bog. I prefer governing to around 5,000rpm, but it sounds mental at 6,000rpm+

[mnipjy]

It's really nice.
Actually, I'm also planning to upgrade core parts with RKH frame and Spin outrunner motor and Lynx swashplate like you did, plus Lynx DFC head.
I think these are the lightest options I've ever searched.
So how's the weight?
Is it light enough comparing to the previous composition?
And how's the flying, like flying time and 3D capability?

Oh, just one more question, are you still using Lynx boom supports?
If so, do they fit well with RKH frame?
(sorry for too many questions)

ps) Thanks again your blheli setup info.

[wadders248]

I've not really had a whole flight at more than 5,000rpm, so I'm still getting almost four minutes of 3D flight. Instead of more revs, I've increased the amount of pitch, I reckon you can run 100% pitch without bogging.

It really is 3D capable, you still have to be quick on the sticks for tight tic-toc's etc., but the Spin motor is just so powerful.

I wanted the DFC head when I was last ordering some parts, but they were out of stock. I'm getting some wobbles past 6,000rpm, which I think might be due to the stock head. The Lynx boom supports work really well with the RKH frame and are a bit longer and more substantial compared to the RKH ones that came with the frame.

I've just weighed it without a battery and it's 58.5g. I could get it a bit lighter by direct soldering the main motor, but it feels very lively as it is. It's definitely the best performing mcpx I've had.

The governor on the BLHeli is just using default settings which need tweaking, though I'll post the settings when I've finished. You really need to run Governor ARM though, so that you can tune the tail motor with the throttle curve.

Originally Posted by mnipjy

It's really nice.
Actually, I'm also planning to upgrade core parts with RKH frame and Spin outrunner motor and Lynx swashplate like you did, plus Lynx DFC head.
I think these are the lightest options I've ever searched.
So how's the weight?
Is it light enough comparing to the previous composition?
And how's the flying, like flying time and 3D capability?

Oh, just one more question, are you still using Lynx boom supports?
If so, do they fit well with RKH frame?
(sorry for too many questions)

ps) Thanks again your blheli setup info.

[mnipjy]

Thanks a lot, as always
It's really helpful again.
Actually, I'm a little bit surprised that it's able to handle such that extreme powertrain with MCPX v2 board.
Maybe you've built a really efficient machine frame, no vibrations at all.
And I really look forward to see your governor setting when it has been finished.
I'll pray for its perfect result.

It's good to see your beautiful bird and hope that I can show you mine soon as well.