Spinning out

[bohh]

Hi,

I'm working on someone elses heli and I'm stuck and scratching my head. It's a helimax 400 with the CCPM conversion kit installed. It has some cheap servos on the cyclic, a HS-81 on the tail and a futaba 240 gyro.

With everything mechanically setup correctly, (tail slider center, tail servo center, etc) the heli will want to nose left slightly at all times in booth AVCS/Head hold mode and rate mode. I can continue to spool up the heli and hold some right rudder in to prevent it from spinning and it will hold. However when I spool up a little more it will violently spin out throwing the battery. It's as if at first its barely moving then - wham! Full spin out at full speed.

The tail is very very touchy as well. Any ideas where I can do from here?

The nose of the heli moves correctly. Right rudder makes the nose go right and visa versa, however I was told that right rudder should move the slider toward the tail case. This is not happening. Left rudder moves toward the case but like I said the nose responds correctly.

Thanks for any help.

[wren1702]

Reverse the direction switch that is on top of the servo.

[bohh]

Tried that. I wish it was that easy. That only makes it worse.

[wren1702]

Is the tail rotor turning up into the wash off of the blades? ie.....If viewed from the disc side of the tail, is it turning counter clockwise?

[bohh]

Yes. Up into the main rotor wash.

[Scottlclem]

I had the same problem , it turned out to a lose hex head set screw that holds tail rotor on the shaft. Hold the main blades or the belt up near the front of the heli and with you other hand try to spin or move the tail rotor. On mine you couldn't tell the tail rotor was slipping on the shaft unless you held the main blades when you spin it.

[bohh]

Tightened that and the belt way up. Can not spin it while holding the main blades. However, it does not spin out now. It will hold its tail and slightly drift left. Upon getting light on the skids the tail is VERY touchy and it is not possible to fly it. Any ideas?

[Scottlclem]

Tinker with the gain on the gyro to get the tail drift out. In your TX set the rudder expo at -30. If the tail is to slugish lower the expo to -25 etc , if it's still to squirly for you go to -35 etc.
Watch the belt tension if it's to tight it will put alot of drag on the heli lowering flight times and all sorts of other problems.You should be able to take a pencil or screwdriver and push one side of the belt towards the other and get 3/4s of the distance between without alot of force.

[stratcat]

ummm, please don't laugh at me here...

I had this same problem, I'd spin up, get to just about leaving the ground and it would go into a tail spin...

I was looking at in sunday and realized that my rear rotor blades were reversed, I was leading with the trailing edges... I reversed them and it now flies.. may be worth checking out...

[Raven_darkcloud]

With a 240 you need some slight pitch. Put it in rate mod and trim for hover. Go back to avcs and you will be good to go. I have setup a few 240s on x400s. Get about 8 to 10mm from center on the servo arm if I remember wright.