BSR - tail motor or gyro?

[peeve1973]

Hey guys,

Something weird happened yesterday with my SR. I have been able to hover the SR and do some side to side and forward and back. But now out of the blue the tail will not adjust properly. I have the reversed tail mod and a GY48V gyro.

I guess to explain it better is that the tail motor will not adjust its running speeds. It either now just runs full blast or very little to not at all. So when I hold the heli after initialization and start to turn it (tail right) the motor kicks in full blast and if I counter it stops all together or just to very minimal speed. If I turn tail to left it stops. And all of this is with my DX7's sticks dead center no inputs at all.

Any ideas?

[John Shipley]

This is normal. Your tail motor only turns in one direction and only corrects in one direction....... that is to turn the heli nose to the right. So when you turn the heli nose to the left, the gyro comes on to try to turn it back. When you turn the heli nose to the right, is shuts off or slows down because it is the torque of the main motor which turns the heli back to center. When you are flying you will notice that when you make a turn to the right, the tail motor is on, but oftern when you turn to the left, the tail motor will slow way down or stop. This is the basic problem with a motored tail.....it can only correct in one direction.....J

[GSPI]

I agree with John on what he said. Is there a performance issue while you are flying that has caused you to ask this question? If there is no performance issue you are good to go as that's what happens with a motored tail like John said.

[peeve1973]

thanks for your replies. I guess what I am trying to say is the tail will run full speed even with no stick input. I then touch the stick to counter the tail and it goes to no tail. I understand how the tail works but it will not even come to hold the tail. It is as if the gyro doesnt want to make the corrections? There is no happy zone.

The thing is it was working just fine until I had a crash....nose into the ground. I have fixed everything and readjusted the swash and blade pitch. But now i have this issue.

Does this help? I will try to see if I can get a video of it later today.

Thanks guys.

[GSPI]

Ok that now makes sense. I had the same issue with my 2 in 1 ESC. I had changed the motor and from my conversation with HH support the 2 in 1 can be effected to do that in a crash situation. If you ever belt the tail you can use that ESC but while you are using the motor you may have to replace the ESC. I had that happen to me so I know that it wasn't the motor but the speed control.

[peeve1973]

Crap! I was hoping it wasn't the 2in1. Reason I say that is my gyro was controlling the tail motor. I guess I will just box it up and give up. I have put a pile of money into it and I still have maybe 10packs of batteries through it hovering and some ff. Maybe its time to let it go. And look at a mcpx or 130x.

I guess I was just flogging a dead horse. I am just not willing to part with another 50$ on it.

Cheers

[John Shipley]

With a 48, 401, or 401 clone gyro, you have to turn the mixing pot off or almost off......counter clock wise. These gyro's are strong enough to run the tail without the mixing pot. What is happening is this, your gyro senses it need to correct. It sends a signal to the esc and the esc mixing pot increases the signal to the tail motor and over drives the heli...nose to the right. This is actually good news in a way because torque and the twisting it causes the heli, can now be delt with in the hard pitch moves.
If you do not have the mixing pot turned off or way down and try to fly, here is what will happen....and this drove me nuts untill I figured out what was going on. I had my heli flying very well. I was doing light weight 3D moves with ease. But if I was inverted and gave a pitch pump, the heli would go beserk in a high speed piro.....it crashed the first few times it happen, but I learned to save it. It took a while to figure out what was going on. I had changed over the gyro to a 401 clone but had not turned the mixing pot down. So when I put in a lot of collective, which gives the most torque, the gyro would give it's maximum signal and the mixing pot would amplify the signal and send too much juice to the motor and wham....the piro of death. I turned off the mixing pot and no more worries.........J

[GSPI]

Ok.. I can see that John. I was thinking that it was the Eflite gyro. Sorry.. try what John said first before boxing it up and giving up. Then let us know.

[Eric_heli]

sounds to me like you need a new tail motor. the sr is a nice bird however the tail burns out fast when your just hovering it. i have had the issue you speak of many times and i always replace the tail motor and its all good.

[peeve1973]

Hi John, I had already turned down the mixing pot to off.

As for the tail motor it had only 5-6 flights on it with oiling after every other flight I would have guessed it would last longer. I will try to change the tail motor once again and see what happens. Unfortunately everything is closed till Tuesday. Will keep you posted.

Cheers

[John Shipley]

A couple of other things to check before replacing the tail motor. I flew mine with full delay and about 65-70% limit on the gyro. Gyro gain on my DX 7 started out at 70%. Have you actually flown this heli?? Or are the test just on the bench?? If you have not flown the heli yet, take off the main blades and spool up on a smooth surface....slowly. Get it up to 1/2 throttle and see if the tail is holding and responding correctly to your rudder stick movements. If it is, then try the same thing with the blades off. If it does not work, tell me what it does.
I have had SR's that the tail would not work up to the point where you lift off and then it would function normally.......J

[Eric_heli]

that is the sad thing about motorized tails. the tail motor can last a hundered flights or just one flight. its the main reason so many do not like helis with tail motors

[GSPI]

I know that I got frustrated so I gave up on the tail and belted it. Now I'm going to put an extra 300X speed control in place and use a higher mah battery too so that I'll have longer run times. Then probably I'll have to do something with the gyro too.

[peeve1973]

Well I now have to rebuild the head since I have now some bad linkages. I have ordered a new heli shell with a belted tail (HK250 clone) and will see about putting the tail on the SR. Or even put the guts of the SR into it. It only cost me $45 and that is way cheaper than replacing electronics and getting a belted tail. Will let you guys know how in the end it all works out.

Cheers

[GSPI]

Yes, keep us posted!