How do I know if my tail motor's burned out? - RC Groups
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Jan 24, 2006, 02:00 PM
more kW, more problems
trashmanf's Avatar

How do I know if my tail motor's burned out?


After trying for a long time to get a good tail hold on my micro heli, I wonder if it could have to do with the tail motor. No matter what I adjust on the potentiometer of the gyro, both the mixing and gain, it won't ever seem to hold it steady, and if it gets close to steady, the tail rocks back and forth (i believe this is the gyro activity) making it extremely hard to hover much less do FFF!

I read a bunch of threads on this forum and it sounds like most of these cheap micro helis have a problem in that their little motors in the tail are flawed by design. I did a lipo upgrade (it's a blade CP) and I put the heat sink on the tail motor, so I hope I didn't burn it totally

How do I find out if it's gone bad? I hope that my only options aren't just to buy a better heli (with shaft or belt driven tail) although it looks like lots of people have put direct drive motors on their blade tails. I dont want to do that if I don't have to tho

I really want to get into advanced helis but I'd like to learn on this cheap one first! thank you experts for any advice you can give me on the subject,

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Jan 24, 2006, 02:10 PM
Eddiemoth's Avatar
For micro helis like Blade CP or Esky HB, you would see your tail gets weaker and weaker and it does not hold it any more regardless how much gain you adjust. If you have it for a while with a lipo I would replace it to see what happens.
Jan 24, 2006, 02:40 PM
Registered User
Motions's Avatar
If the tail is wagging back and forth, your gain is set too high. If it has the power to wag, the motor should be good. Try adjusting the gain to about 1/2 to 5/8 and try it.

When you make adjustments to the proportional and gain, make very small corrections. They are very sensitive.
Jan 24, 2006, 02:41 PM
IF it spins like a top, then its dead Seriously, they do get weaker sometimes before going. Mine have just quit, one in the air. Interesting. Looked like a pinwheel!
Jan 24, 2006, 02:52 PM
Registered User
If you and anyone else are tired of going threw tail-motors, might wanna try one of these???
Jan 24, 2006, 03:58 PM
more kW, more problems
trashmanf's Avatar
thank you for the tips. I will try turning the gain down, even further than I have... can I use the rudder trim tab on the Tx then to get it to straighten out?

I read through your link bonzer (about the tail motor save) I think that sounds like a goood idea, but I will probably wait until I burn out a tail motor to see if I really need it, I don't fly that often (although if I can freakin get my heli to work right, I should be flying a lot more!)

I will try and mess with it with your guys' tips, and post if it is working !!!
Jan 24, 2006, 05:16 PM
Registered User
On My honey CP2 I noticed the tail motor starts to go (sliding left) 1/2 way thru the pack....SO....In my infinite wisdom I turned the Prop + Up just enuf till the heli was turning/yawing right at 1/2 throttle (in Gov mode hovering) then adjusted full left rudder trim on the TX and Wala...By the end of the pack I've adjusted the trim almost all the way to the right..Never run outta Tail trim ! You really only notice it anyway when hovering. I've got the Geared Stock tail same one since new... I did notice that Prying the 4in1 off of the Frame and laying it on some nice Futaba foam I dont have near the tail probs...My stock foam was more tape than foam..the last thing would be heat....I can hover in my house for about 4 to 6 min then the chopper gets posessed..I've also run a pack out in my house with the 4 in 1 apart and wala smooth as silk ! Try One Try All ! Or buy a new tail motor ! lol
Jan 24, 2006, 06:26 PM
Get back here, you!!
bikenboatn's Avatar
If you're getting tail motor pulsing even with the gain turned low, another thing to check is the double-sticky foam tape holding the 4-in-1. If the 4-in-1 is a little loose, it will move around during flight, the gyro will sense that, try to correct it, the 4-in-1 moves, gyro corrects, etc. etc.

Jan 24, 2006, 06:37 PM
Registered User
If you can get your heli to wag (because the gain is up too high or the 4 in one is loose) then I would say your motor is just fine.
When my tail motor started to die it would fly fine for a minute or so until it started to heat up then start to go into the piro of death as the motor looses power and just cant keep it straight. That was a quick lesson in knowing what to look for when it comes to motor wear. When the main motor starts to puke it just slowly looses power until it cant lift it's own weight any longer...
Jan 24, 2006, 06:51 PM
Registered User
LuckyDuc's Avatar
How many flights does your tail motor have on it? Mine normally failed around 40 flights.

Buy another and see if that solves the problem. I bet it will... for a short time anyway.
Jan 24, 2006, 08:16 PM
RC Geek
Scott_NJ's Avatar

I think a big thing to look at is that when your spooling up the main blade it is going to want to rotate and you might need to give it some left stick to hold the tail. Once it gets up into a hover you shouldnt need as much left, but it will tend to change as the pack runs down.

Jan 25, 2006, 12:55 PM
more kW, more problems
trashmanf's Avatar
THANKS everybody for all the tips!

I did notice that my gyro is a little shaky on the plastic mount - I will put some foam on and cinch it down tight.

I tried a bunch of your guys' ideas and nothing was seeming to work. I noticed when closely looking at it during the tail wags, that the whole tail area seemed to be shaking violently during the wags. After messing around a bunch, I just wiggled the tail when the heli was OFF, and I noticed that there was considerable give, as well as a strange crunchy sound

turned out that I had a cracked tail boom!!!!!!! I have no idea how long I've been flying like that. it was flexing under certain harmonic stresses during the flight, causing wag of course. I can't believe that it didn't break, that would have been disastrous.

i taped another carbon fiber pole to the boom and it flew much better I'm gonna start scouring the 'for sale' forums and try to find a CNC frame that nobody's using...

thanks again guys for all the tips!
Jan 25, 2006, 01:42 PM
Eddiemoth's Avatar
I don't know if this is going to help but thought it does not hurt for me to share. My Blade CP for some reasons does not like my TP battery escpecially when the battery is freshly charged. The tail would wag vilently and I have to land it or I crash it. It get better when it gets to the end of the pack. When I swaped the TP battery with the RC Expert battery came with my Esky HB (I consider this is a weak lipo battery) the problem is gone. Ironically - my Esky HB does not have this problem with my TP battery. I don't know if your Blade has everything seperated or 4 in 1. If it is still 4 in 1, that might be the case.
Jan 26, 2006, 04:47 PM
more kW, more problems
trashmanf's Avatar
hmm... it does have the 4 in 1. with the aerobatic upgrade I assume I have to run 3s lipo, or else I would try the ol nimh pack and see if it wags. the tail seems to be holding MUCH better with the tailboom reinforced, duh I'll probably have to get a new tailboom or maybe one of those CNC frames.

edit: then if it still wags and freaks, I will try a different battery!
Jan 26, 2006, 05:38 PM
Registered User
Motions's Avatar
The ol' cracked boom is hard to find sometimes. I have flown mine for a while with a cracked boom and didn't even know. I got in the habit of tugging on it after every flight just to make sure.

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