mcpx bl heli goes left by itself?

[hydrojeff]

hello all, I have been flying the heli a while now and it just started going left just as if I was giving it left input? I have cleaned the servo but it still does it. I can still control the bird but it takes quite a bit of right stick, I give a couple of pumps of cyclic and it may stop or it may not. when I land and have no input the left servo is down about 1/16 of an inch. some flights it doesn't do it. its weird, you will be just hovering and it just goes left pretty hard? I have looked and not seen anything on the forum quite like it. thanks for the help.

[learnedthehardway]

Servo might be sticking a little/starting to go bad. Maybe some vibes going on somewhere?

Idk but it sounds like the gyro part of the 3n1 might be on its way out. I had bad luck with the BL, first board puked on flight 6 without a single crash. HH replaced the 3n1 then around flight 80 it started drifting erratically like yours is. Took some convincing but they sent me another which cured the drift. Sold mine right after that since it had two board failures, tail motor failure and twitchy servos all in a month's time.

Might be time for a new 3n1 or send it to megas micros for repair

[Krager]

Those linear servos are high maintenance. I've gotten pretty good at cleaning them. I would try that first. Remove the plastic cage holding the drive and wipe the pot strips clean with alcohol, maybe some fine steel wool if they look really dirty.

One problem with cleaning is the little screws that go into the plastic cage can strip easily. I've found a little CA applied with a toothpick to the plastic threads can resolve that. Just be careful not to get the CA where it can cause the board and cage to get stuck together.

Assuming the swash is properly leveled and servo action seems smooth when exercised, it's probably a board failure which is common, but on the mCPX BL it's usually the motor controller part that fails.

I had a board failure on a Nano CPX that did pretty much the same thing. Flew it into a pole hard in FFF and the board went wonky after that. Though that board did take quite a bit of abuse before that.

[hydrojeff]

thanks so much for your replies, I do have a used servo out of a mcpx I will swap and see if that helps, I also am going to call HH and see if they will send a board as well? I will try the light steel wool and see if that helps,,, thanks again guys!!!

[Krager]

That's probably why Blade dropped the mCPX BL so fast, it was a problematic micro, lots of board failures and tail motor failures. With all the boards they had to replace I'm sure they didn't make any money on that model. The heli does fly well when it's working right, but keeping one going can be a chore.

I have one, but there's nothing Blade left on it, all aftermarket stuff with a uBrain. It's an awesome little heli. I spent as much building that one as a 450. Might seem ridiculous, but it's a great size for flying in the yard. It has an outrunner tail motor and 130 X size outrunner main with 130 X size main blades. Not the same heli at all. It's more like a 130 S, except with a proper adjustable FBL controller and about 90g lighter. It actually has the lowest disk loading of any of my helis and a really impressive collective punch.

[Chris1683]

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[Chris1683]

I had a similar issue and it turned out to be a bad board. I tried new servos also and it didn't solve the issue. Slapped in a new board and it worked perfectly. I agree that this is a high maintenance heli and that's probably why HH dropped it like a crazy girlfriend.

[hydrojeff]

I tried changing the servo and its still the same issue, can I have the board repaired or should I just scrap it, HH has a new board for 62 I think? how is the Ubrain, is it pulg and play?

[T_Dogg80]

Originally Posted by hydrojeff

I tried changing the servo and its still the same issue, can I have the board repaired or should I just scrap it, HH has a new board for 62 I think? how is the Ubrain, is it pulg and play?

You bet you can! https://www.megasmicros.com/Repair_S...repair-all.htm

[hydrojeff]

thanks for your help guys, I think I will get it repaired.

[Krager]

Originally Posted by hydrojeff

how is the Ubrain, is it pulg and play?

Far from it. First you have to figure out a way to mount it. Then the plugs are different on the servos. I actually soldered in new pigtails on my servos. Then you need a dual ESC with a 5V BEC since the servos can not handle more than that and the uBrain has a 4.7V minimum. Well the servos might be able to handle 5.5V but that would be right on the edge. I'm pretty sure that's absolute maximum for the regulators used on the the servos. Then the whole mod adds a few grams of weight, turned out to be 5g for me. Though if you're willing to go through the gyrations there's a huge difference between Blade's controller and a fully adjustable flybarless controller like the bigger models fly. You can also use much more reliable and efficient ESCs compared to the ones on the 3-in-1 board. Then you'll want outrunners on the main and tail. It's actually quite a can of worms to open, but you'll end up with a first class heli.

[hydrojeff]

wow Craig, that looks sweet, you do great work,,, thanks for the info. I should be getting my board back today so we will see how it goes or how long it lasts.

[Krager]

Thanks. I enjoy the hell out of that little heli. Flys really nice and has pretty low disk loading, weighs 83g all up and spins 125mm blades at 5600 rpm. Amazing how well the Brain works on a micro heli with linear servos and a motored tail. Those are some talented engineers over at MSH.

[hydrojeff]

just got my board back from megas micros and tail doesn't hold at all?
it will float from full left to full right with no input. I even tried changing tail motors and tried the lynx 3 blade tail prop? I messaged micros to c whats up.

[Krager]

That's a bummer. Sounds like the gyro chip on the board has had it. Is that something MM can replace?

[hydrojeff]

yeah I thought they would have? I tried messaging them with no response? the receipt I got from them just says board repair. I think im going to cut my losses and sell it and that's too bad because I loved the power it had!!!

[fabian1675]

Originally Posted by CraigHB

Far from it. First you have to figure out a way to mount it. Then the plugs are different on the servos. I actually soldered in new pigtails on my servos. Then you need a dual ESC with a 5V BEC since the servos can not handle more than that and the uBrain has a 4.7V minimum. Well the servos might be able to handle 5.5V but that would be right on the edge. I'm pretty sure that's absolute maximum for the regulators used on the the servos. Then the whole mod adds a few grams of weight, turned out to be 5g for me. Though if you're willing to go through the gyrations there's a huge difference between Blade's controller and a fully adjustable flybarless controller like the bigger models fly. You can also use much more reliable and efficient ESCs compared to the ones on the 3-in-1 board. Then you'll want outrunners on the main and tail. It's actually quite a can of worms to open, but you'll end up with a first class heli.

Nice work.

Would you mind telling us the hardware you use. ESC, Motors main and tail.

What configuration did you have to change to micro brain to get it to work with tail motor.

Thanks.

[Krager]

Thanks.

For a motored tail the uBrain actually works without doing anything unusual using a regular BLHeli ESC (not the S or 32 bit versions for quads). That's loaded with the Tail version of the firmware. I did do something a little unusual with the BLHeli setup, but I'm not sure it's even necessary. What I did was set the range on the uBrain to standard timings, but on the ESC I set it shorter on the negative side to make it look more like a servo to the uBrain. That's with normal motor direction set in the tail firmware. I did try bidirectional, but the uBrain can't deal with the lag and destabilizes when the motor changes direction.

I made my own dual ESC, but there are light 2S ESCs you can find that will do the job. Just have to use two instead of the single board I built myself. You do need a BEC if you can't find a small ESC with one. The uBrain can handle 2S voltage, but the servos can't handle more than 5V. I made a little 3A switcher myself, but it might be a bit hard to find something small enough.

The tail motor is an OverSky HP03T and the main motor is an HP08S. Though you can find motors on Banggood a lot cheaper that can do the job. The OverSky motors are over-priced in my opinion. The pinion is a little bit of an issue. With the 1.5mm shaft the smallest pinion available is a 9T which is a little tall for the mCPX, but probably okay anyway. To use an 8T pinion I had to step the shaft to 1.2mm. With the right Kv on the main motor it shouldn't be a problem to run a 9T pinion. For the motor Kv I was using I needed the stock gearing.

You really need to get the Kv right on both tail and main for 2S. The main motor I'm using is 7600 Kv, but that can vary depending on head speed and gearing. I'm using the BLHeli governor set to 5600 rpm with the stock 8:1 gearing. I did have some trouble with the tail motor. The HP03T I bought was 4000 Kv originally, but I had trouble with tail authority getting blowouts at max pitch. I rewound that motor to 6000 Kv and now the tail holds solid.

I'm running 125mm blades. I was using Lynx stretch mCPX blades initially, but they don't make them anymore. Now I'm using Fusuno 130 X blades trimmed down to 125mm. It can actually swing the 135mm 130 X blades no problem, but it feels better to me with 125mm blades. Disk loading is already really light, the longer blades don't help much and make the heli feel more twitchy.

On the tail rotor I'm using a Lynx 47mm two blade. That's a big rotor, but it needs the authority. They've actually discontinued that rotor, but I still have a number of them on hand. When I need new ones I'll just use the 45mm three blade they sell.