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Help! New problem: Bad ESC?

#1
I recently bought a Durafly Spitfire Mk24 V2 from HobbyKing, and assembly was going fine until I had trouble with the flap servos. They were pretty close to being centered, but one flap was clearly not matching the other. The servo arms have an S on one end, and an adjustable eyelet at the other. After fussing with screwing them in and out, and trying to make sure I hadn't messed up some radio settings, I realized that though the arms provided are identical, there is about a 5/16th of an inch difference between the servo horn and the flight control horn, even with the control rods screwed in or out to their maximum adjustment.

In essence, the servo slots are not identically placed on this plane, and the provided servo arms cannot be adjusted to match. Has anyone else experienced this? Is there anything that I can do other than drive an hour to the hobby shop and buy new arms and bend them myself? Also, I can't seem to get a screwdriver in to adjust the servo horn without stripping the screw.

Left wing length approximately 1 and 5/8ths
Photo May 14, 18 04 40.jpg
Right wing length approximately 1 and 15/16ths Photo May 14, 18 05 20.jpg About 1 and 3/8ths Photo May 14, 18 05 40.jpg About 1 and 9/16ths Photo May 14, 18 06 05.jpg
 
#2
It looks to me that one servo arm needs to be taken off an centered. so power them up until they self center then remove the screw from the servo arm, take the arm off and move it to where it needs to be
 
#3
It looks to me that one servo arm needs to be taken off an centered. so power them up until they self center then remove the screw from the servo arm, take the arm off and move it to where it needs to be
I think that is certainly part of it, but the servo is literally farther back on the one side. Also, the screws are in so tight I can't seem to get them out.
 

Hai-Lee

Old and Bold RC PILOT
Mentor
#4
If the servos cannot be mechanically balanced for equal distance there is another way!

Go to the transmitter and adjust the subtrim for equal distance and hence mechanical travel.

I sometimes have to do this where the arms of the servo cannot be made of equal angle when centred.

Just what works for me!

have fun!
 

Bricks

Active member
#5
First question are you using a Y cable? If not then do as Hai-Lee has mentioned distance from control arm to servo does not make any difference as long as the same hole in both servos from side to side are used. Just like a dual elevator servos they are offset in the fuselage as the fuselage is not wide enough to set them even to each other.
 
#6
If the servos cannot be mechanically balanced for equal distance there is another way!

Go to the transmitter and adjust the subtrim for equal distance and hence mechanical travel.

I sometimes have to do this where the arms of the servo cannot be made of equal angle when centred.

Just what works for me!

have fun!
I'm not sure that is possible because they are wired through a Y harness. Anytime I adjust the subtrims, it adjusts both of them. I ended up going to the local hobby shop and getting an adjustable control rod and made it fit. Thanks for your help though!

I flew it yesterday and it flew great. Half way through the second battery (about five minute flight on the first battery and five by this time) the motor started to shudder and make some not great noises. I brought it in, and ran the engine up on the ground. It is still sputtering and chattering occasionally, and losing power. From what I have read it could be a bad ESC, but I'm really not sure at all. I guess I'll order a new one and see what happens..?

I was flying with a 45A ESC and a 30C 4S 2200mah.
 

sprzout

Knower of useless information
Mentor
#7
What size motor and prop were you flying with on that esc? It's possible you might be running too much current through it with that 4S...
 
#8
What size motor and prop were you flying with on that esc? It's possible you might be running too much current through it with that 4S...
It's the 5 Blade 11" with a 580kv motor that came with it. The HobbyKing website recommends a 4S 2200.

Should I buy a higher rated ESC to replace it?
 

Hai-Lee

Old and Bold RC PILOT
Mentor
#11
I'm not sure that is possible because they are wired through a Y harness. Anytime I adjust the subtrims, it adjusts both of them. I ended up going to the local hobby shop and getting an adjustable control rod and made it fit. Thanks for your help though!

I flew it yesterday and it flew great. Half way through the second battery (about five minute flight on the first battery and five by this time) the motor started to shudder and make some not great noises. I brought it in, and ran the engine up on the ground. It is still sputtering and chattering occasionally, and losing power. From what I have read it could be a bad ESC, but I'm really not sure at all. I guess I'll order a new one and see what happens..?

I was flying with a 45A ESC and a 30C 4S 2200mah.
I had a motor/ESC combination do a similar thing on one of my aircraft and Out of frustration I replaced both the motor and ESC and the problem was gone. Being a little inquisitive and finding a little spare time I decided to investigate and the ESC testing showed it was faultless. So I undertook to disassemble the motor and investigate. It did not take long to find a problem.

One the motor I was using, (a HK sourced 2205c 1400kV), the leads from the motor are actually three wire each which are used to form the motor coils/poles. Well it appears that due to my installation and the way this motor had been wound that a single wire of the windings to one of the motor leads had broken. When the broken winding was touching the motor worked perfectly but when the motor leads moved slightly and the single winding wire separated the motor would immediately lose power and if I tried to start the motor in this condition the motor would stutter and make strange noises occasionally until it managed to start in the correct direction.

I had a close look at the motor windings, (I had persevered with the problem for many flights before I replaced the motor/ESC), and I noticed that about a third of the windings were still bright and shiny and the other two thirds had become discolored from overheating.

I did a bit of microsurgery and joined the broken motor winding and the motor is now operating properly and is flying reliably in a different installation.

Whilst this may not be your problem it does sound suspiciously similar.

Have fun!
 
#13
I had a motor/ESC combination do a similar thing on one of my aircraft and Out of frustration I replaced both the motor and ESC and the problem was gone. Being a little inquisitive and finding a little spare time I decided to investigate and the ESC testing showed it was faultless. So I undertook to disassemble the motor and investigate. It did not take long to find a problem.

One the motor I was using, (a HK sourced 2205c 1400kV), the leads from the motor are actually three wire each which are used to form the motor coils/poles. Well it appears that due to my installation and the way this motor had been wound that a single wire of the windings to one of the motor leads had broken. When the broken winding was touching the motor worked perfectly but when the motor leads moved slightly and the single winding wire separated the motor would immediately lose power and if I tried to start the motor in this condition the motor would stutter and make strange noises occasionally until it managed to start in the correct direction.

I had a close look at the motor windings, (I had persevered with the problem for many flights before I replaced the motor/ESC), and I noticed that about a third of the windings were still bright and shiny and the other two thirds had become discolored from overheating.

I did a bit of microsurgery and joined the broken motor winding and the motor is now operating properly and is flying reliably in a different installation.

Whilst this may not be your problem it does sound suspiciously similar.

Have fun!
That sounds very similar to my problem. I went ahead and took the motor and ESC completely out of the plane and inspected it. I couldn't find any problems (though I didn't take the motor apart) and I put everything back together. I flew it again two nights ago and I only had intermittent chattering maybe two or three times, which was much better than before. It seemed to happen on high power, low speed climb outs. I'm not sure if that has anything to do with it.

Thanks for everyones help, its much appreciated. I'll add an update if I have any new findings.
 

PsyBorg

Fly Angry
Mentor
#15
If you have a multi meter you can do two tests on the motor. First do a resistance check pole to pole. Wiggle the wires where they enter the motor and see if the resistance changes in one of the poles. If so you have the same situation Hai Lee had.

Next you can put the motor in a hand drill and spin it. Measure the voltage produced at each pole and again wiggle connections around to look for any variances.

If all those values are stable and relatively close then you should look at the esc. Finally... a 5 blade prop depending what pitch could easily be overheating the motor and may have caused damage if the current draw was super high on any motor. This would also play into the theory of C rating of your battery having issue keeping up with need but that would not be effecting low power operation so much.