motor issue

[plingboot]

just had chance to test the naza with the new gps doohicky, on my HT-FPV frame.

generally it seems pretty good - i was up a hill, the wind was blowing, but it did a pretty good job of staying reasonably well put.

i was also having general test of the HT-FPV as it's a new build.

when flicking the controls to see how well it kept level i encountered a serious (crash) issue.

if i flick the right stick - to get a rapid side-to-side movement i can hear the front right motor make a kind of cogging sound which is rapidly followed by the bird pitching over and crashing - luckily i was only a couple of feet up, over very long grass and the HT-FPV is built to last.

I can replicate the issue time after time and it's as though something can't respond to a rapid need to change speed. Everything seems fine when flying in a sedate fashion, but any sudden control changes and there's problems. I don't think it's a naza issue, so assume it's either esc or motor related - anyone have any ideas?

Using hobby wing sec's and pancake t-motors.

 

[Elliott000]

Does it do a crazy wobble as if it was hung by the two opposing motors.

 

[plingboot]

it wobbles about and pitches over toward the motor which made the cogging sound - it's not a frantic thing, but pretty catastrophic non-the-less

 

[kristiaj]

Could the cause be that the IMU idle throttle is set to too low, so one of the engines stops and fails to start again because of wind resistance?

 

[Elliott000]

I have a thread in the dji section titled have a look or something showing what mine did.... Never figured it out. The only cure was to put dji 30 amps back in. Im going to try again this weekend more with timing and ill try dji motor instead of my rc tigers

 

[DennyR]

Yes I do know what the problem is. you have a Kv mismatch there plus. the esc is loosing the phase switching. Which T -motor is it that you are using. As I recall it's the 3506 that is the real problem one. . Only the very latest HW ESC with 4.1 firmware will work those motors. The Suppo Motor 50A ESC with 4 timing settings will also work

Another problem that you may encounter is that these motors are sensitive to the width of usable power band. i.e. if you under prop. the motor it will not have enough available rpm to deliver the extra thrust needed for stabilization. On the 4006/600kv. that I use, it will not stabilize at all on a Graupner 10x5 but will fly perfectly on a special that is about 11.5x4.5

When they are set-up right they are amazingly smooth. Needs 4s battery

When testing your motors individually you should always snap open the throttle to check that it will not spit the dummy.

 

[Elliott000]

Thans for the info man awesome to know, im on 4s. They are the 2216 900kv, i hope u figure yours out.... How do ino what esc firmware im on, they are a month old

 

[plingboot]

denny, thanks for the reply. When you say Kv mismatch - could you elaborate?

i'm running the 3506s on 4cells with 10x5 graupners. The esc's are HobbyWing Flyfun 30A, but no idea what firmware they're running.

Any thoughts on which timing setting gives best results?

I've got a set of 11x5 graupners in the box which i might try.

For the moment i've swapped the motors for some spare torxpower ones i had in the spares box.

Do need to get this issue sorted though - i've got a TBS Discovery to build next week which will need to use the 3506's - as they're the only motors i've got left now…

 

[DennyR]

The timing will for sure need to be high. Contact Jeremy at Electriflite.co.uk for info on which model of HW ESC has the right firmware. I don't think you will have any luck with the 10x5's but maybe the 11x5 will work ok, as I recall the 3506 is 660 Kv. which is dangerously close to running out of rpm at the end of the flight.....

If it is a flame wheel, or similar, that you are using and you don't have any luck with this combination. The best that you can get for not much money is the Suppo Motor 2814/8 which is the best motor I have ever tested. Goes great with a 10x5 G. You can also run it on a 30A.simonk reflashed ESC.

If you end up with the Suppo ones, don't try to shorten the motor cables from the motor. These are the shellac covered motor winding wires and are difficult to solder. You have to clean each of the 8 wires to ensure that all of them make a good soldered joint. Better to use the factory tinned connection.