Need help analysing motor cut issue FT Mini Guinea

[NoobMicka676]

Hello everyone ,

I've build a Mini Guinea and it fly perfecty 4 lipo and came back home. Came back yesterday to fly it more and it fly perfect but suddenly motor cut out not sure if i was controlling the thing but the Gyro seem to have land the thing carefully even if I did the dead stick thing. I was low on throttle compare to the other day so why suddenly. Batterie was at 3.96v 3s even if I search the damn thing for an hour No voice telling i lost rx signal..

2xVGood ESC 12a 2a bec one bec disconnected
2x Racerstar 1804 2300kv - y wire
4x 4.3g K-Power servo ( 2 are y wire ailerons )
HobbyEagles A3 v2 Gyro
3s 850 mAh tattu lipo
5045 propeller Masterairscrews bn
Jumper T-Lite
Radiolink R8ef 1.2 km range

 

[NoobMicka676]

What could be the issue please ?

Thank you
Michael

 

[JasonK]

hmmm 3.96v is in a 1s level voltage range, that is what you were reading for a 3s or just 1 cell of your battery?

did you try flipping it into manual mode (no gyros) and seeing if it flew ok that way to make sure it wasn't some sort of gyro issue?

 

[NoobMicka676]

hmmm 3.96v is in a 1s level voltage range, that is what you were reading for a 3s or just 1 cell of your battery?

did you try flipping it into manual mode (no gyros) and seeing if it flew ok that way to make sure it wasn't some sort of gyro issue?

3.96v each 3 cells. And no i didnt have to time to try it but it is a good Idea thank you.

 

[JasonK]

The gyro seem to be Working find because i think it would have crash but I dont discard the Idea.

the guinea should be reasonably stable and should fly straight and level (assuming it stared that way) with 'dead sticks at neutral' so it shouldn't have required the gyro to continue to fly straight.

 

[NoobMicka676]

Okay yes i see because i Never had fly the mini Guinea before this plane.

Could it be ESC overheat ? The motors are wired with an y cable.

 

[JasonK]

it _could_ have been all sorts of things.

But the only items you have indicated was that you had an aileron cable loose (which would have caused some issues with roll primarily) and the lack of being able to pull up

 

[NoobMicka676]

Yes that what i thing too and it was perfectly stable. Not the cable. Servo was unglued but working.

I have a large capacitor that can connect to rx or gyro but i would go rx even if i dont thing IT would solve the probleme either.

I can buy a external bec 3a.

Next Time i Will try to put the gyro off i have a switch for that

 

[NoobMicka676]

Yes that what i thing too and it was perfectly stable.

I have a large capacitor that can connect to rx or gyro but i would go rx even if i dont thing IT would solve the probleme either.

I can buy a external bec 3a.

Next Time i Will try to put the gyro off i have a switch for that

It look like a lost of signal but the range alarm was Working find because i Found the plane with the alarm of the rssi when i was too far on the plane.

The signal was lost once it was landed in the field so normal.

Lipo was one of the same that I had great result on Maiden.

The plane was working fine once recovered with the plane still powered on.

 

[NoobMicka676]

Maybe over propped i have some Masterscrews 5045 bullnose


I will change for 5x3 HQ prop and i've put the hobbyeagle large capacitor in a channel not use in rx.


Let's see if it help and i thing that my post will maybe help some people.

 

[Hai-Lee]

I must ask what battery are you using and also what size motors.
If you are drawing too much current from a single battery, (more current than the "C" rating of the battery it is possible that the battery voltage is collapsing and the 2 motors may not have exactly the same power or rotation speed at low voltage.

A difference in motor output or even a small difference in the voltage at which the ESC activates its battery protection circuitry could cause a motor to slow dramatically or even stop altogether and often for the plane to suddenly want to turn or roll.

Try to ensure that the battery can support the motor current requirements under full throttle and for a reasonable length of time. Remember batteries have their internal resistance increase with age and usage and this will cause the battery terminal voltage to drop or sag under load.

Have fun!

 

[NoobMicka676]

I must ask what battery are you using and also what size motors.
If you are drawing too much current from a single battery, (more current than the "C" rating of the battery it is possible that the battery voltage is collapsing and the 2 motors may not have exactly the same power or rotation speed at low voltage.

A difference in motor output or even a small difference in the voltage at which the ESC activates its battery protection circuitry could cause a motor to slow dramatically or even stop altogether and often for the plane to suddenly want to turn or roll.

Try to ensure that the battery can support the motor current requirements under full throttle and for a reasonable length of time. Remember batteries have their internal resistance increase with age and usage and this will cause the battery terminal voltage to drop or sag under load.

Have fun!

Hello Hai-Lee , thanks for your awesome answer ! I don't know if it is my problem but i check it out and forgot I'Ve bought the Tattu 850mah 3s 45c but there some 75c would it be better with 1806 2280kv Racestar ?

 

[NoobMicka676]

It's seem that with a capacitor and smaller prop 5x3 didnt fly well. And another motor probleme because it as shut down once again.

 

[quorneng]

NoobMocka676
The best protection from a battery voltage drop is capacity.
I note that with 5x4.5 props on 3s you could be easily drawing 12A for each motor so the 12A ESCs may well be cutting out. In addition 24A from an 850 mAh battery is working it pretty hard, about 30C, which corresponds to a full power duration of only 2 minutes.
Can you measure the Amps being drawn from the battery? Both to establish how close you are to the ESCs maximum and how hard you are working the battery.

 

[NoobMicka676]

NoobMocka676
The best protection from a battery voltage drop is capacity.
I note that with 5x4.5 props on 3s you could be easily drawing 12A for each motor so the 12A ESCs may well be cutting out. In addition 24A from an 850 mAh battery is working it pretty hard, about 30C, which corresponds to a full power duration of only 2 minutes.
Can you measure the Amps being drawn from the battery? Both to establish how close you are to the ESCs maximum and how hard you are working the battery.

I will buy a watt meter and see. What you said might be my problem because i have 4 minutes and half flight time at 45-50% throttle. Each cell 3.85 at landing

How can i make to flight time longer ?

Another problem it doesn't want to lift with HQ 5x3 on 3s and HQ 6x3 on 2s but work well with DAL Bullnose 5045 2s and DAL Bullnose 6045 on 3s .. I think i need a balance too it might be too heavy

 

[Bricks]

With dual motors did you disconnect either the + or the - from one of the ESC`s to the receiver, this can cause all kinds of funky things to happen.

 

[NoobMicka676]

With dual motors did you disconnect either the + or the - from one of the ESC`s to the receiver, this can cause all kinds of funky things to happen.

Yes i did disconnect one bec from 1 ESC

 

[NoobMicka676]

I've receiver the watt meter and even at 75% throttle i am only at 7a for both motors.

It doesn't seem to be my BEC honnestly even if I go wild on the sticks.

I've use many brand of propellers and size. Same result.

I've notice that the last time it happen i had to verify the lipo and it seem a little puffy .. Humm maybe each time I got the problem it was maybe this same lipo.

quorneng Thanks you put me on the right track !!!

What a dumb Noob mistake Many thanks to all of you !!