OK, I think I need some help on this one.

I've been building little quads to stay under weight limits and made all the usual mistakes but starting to get OK at the basics.

But I thought I should really get a 5inch build going, it's a bit of a mashup of old parts, cheap bits and cable ties.

It takes off nice but as soon as I try any flips or rolls it death spins out of the air and hits the ground hard.

Here's a video of the latest crash:



Setup is:
CLRACING F7 V2.1 MPU6000 30X30 FLIGHT CONTROLLER
FLYCOLOR RAPTOR BLS 30A 4IN1 ESC (2-4S)
Racerstar SPROG X 2207 2400KV 3-5S
HSKRC Foss 210 4mm Arm 3K Carbon Fiber 5 Inch
Chinahobbyline CNHL G+PLUS 1300MAH 14.8V 4S 100C Lipo 

8k looptime and RPM filtering as per Oscar's blog post setup. Air mode is on.

Arms (were) nice and stiff.


Here's a pic after that crash. Whoops, guess it'll need a new frame.



The Blackbox log is attached, I don't know how to read it properly but should motor 1 be jumping to 100% after the roll be a concern.

The flight controller is new as the old one ripped it's USB port off on the previous crash.

So I don't know, could it be:

- esc
- a motor
- a capacitor issue (wrong one, wires too long)
- or is the battery too big/loose? throwing things off balance?

Thanks in advance for any advice, it's appreciated.

Ok, so i did some quick testing on the bench to see if could see motors desynching.

Took the props off, hooked up betflight and ran the motors individually. Here is the dumbass question. Should the motor be pouring out smoke when lifted to full throttle?? (no, i'm guessing)

So looks like Motor 3 is busted? Or what else would cause that?

Thanks

thats a died motor than hopefully it was the source and a replacement arm and motor fix it

I don’t believe it is good to run a motor full throttle with no load. Someone correct me if I’m wrong.

yess i agree, its more of a torture than a test, there is no usable result from it; the most weak part will fail first hopefully that motor was the issue

OK cool that's good to know.

I tested the motor that was smoking with an old flight controller and ESC i have for testing and it smoked again.

Then I switched one of the other motors to where the smoking motor was connected to the esc.

It spun fine with out any smoke. So looks like the motor was the culprit? ESC should be OK?

Is there a better way to test without giving them throttle through betaflight?

Thanks

Updating this for future readers who might have simillar issues.

I switched frame and motors. Still had the same issue.

So I tried increasing idle throttle to 7%. Nope, still hit the ground on a flip.

Then I tried increasing Demag Compensation in ESC firmware settings to high (JESC firmware in this case).

And it worked! Quad is now flipping and rolling as expected.

(20-Apr-2022, 05:20 AM)joewickert Wrote: Updating this for future readers who might have simillar issues.

I switched frame and motors. Still had the same issue.

So I tried increasing idle throttle to 7%. Nope, still hit the ground on a flip.

Then I tried increasing Demag Compensation in ESC firmware settings to high (JESC firmware in this case).

And it worked! Quad is now flipping and rolling as expected.

Good update!

Im assuming you replaced the smoking motor.
The smoke is plastic enamel on winding burning. Without it wires can short, and motor will stutter or wont work at all.

When you first build the quad, its good to check parts BEFORE soldering or connecting battery.
1. Connect FC to PC USB. Make sure gyro works.

2. Pull motor wires lightly and make sure it turns smoothly. Cogging from strong magnets is normal. Rubbing or scratching is bad.

3. Measure each motor pair resistance. Should be identical.

4. Measure each ESC motor pad continuity to Vbat and Gnd. Continuous beep = bad.

Again, do all these before soldering or connecting battery.