Blade 400 spin

[dmiley]

Hey all. I've been reading here for a while but this is my first post. Great information here by the way.

First off, I've read the threads I could find on this topic from my searches but I haven't found a solution yet. I had a small crash and a resulting blade strike. I have replaced the necessary parts that were damaged (feathering shaft, main shaft) and have double checked everything to be sure the swash plate and the rest is level. Now the problem: when power up the heli spins to the left (ccw) and no amount of right stick will bring it back. It did not do this before.

I double checked everything from the main gear out and everything seems to be in working order. I even replaced the servo with a spare I had to eliminate stripped gears. This is driving me nuts.

I'm running the stock gyro and the stock tail servo (yes I know I should replace it). Is it possible that the gyro has gone bad? I mean at this stage the only thing that's overtly obvious to me. Everything else seems in line. I've gone over it multiple times and can't for the life of me see what could be causing this.

Like I said, I've gone through the other threads with similar topics as this but the solutions there didn't really apply.

One last thing, I notice that in HH mode the tail will not re-center itself if I give it left stick. Right stick it will, left stick it won't.

Ok, there ya go. Any and all ideas would be greatly appreciated!!!

[widower]

So if you're in rate mode, does the tail slider center? Then right and left stick inputs cause the tail slider to move completely to the left and right?

Also, to rule out striped gears in the tail servo, apply a small amount of pressure with your finger to the tail servo while moving the stick left and right.

BTW: do this with the motor unplugged, or throttle hold.

[Skarn]

In HH mode, the servo will not center itself after rudder input. This is normal.

As far as your problem, check your belt to be sure it's not skipping, check that the gears the belt wraps around is not stripped and slipping and check your one-way bearing to be sure it's working. Hold your main blades and attempt to spin the tail blades....they should not be able to move if you hold your main blades.

Skarn

[dmiley]

Ok, thanks for the replies.

1) I put it in rate mode and (after I corrected my centering a bit) the tail slide does center itself.

2) Back in HH mode, as I throttle up it gets harder and harder to hold the heli until finally even at full right stick it will spin even before take off.

3) I'll recheck the belt and gears. Would I not be able to hear the belt skipping? Just curious to know if there's other ways to detect it.

4) edit** I also checked the servo by applying a small bit of pressure as suggested. Everything checks out on it.

Thanks and I'll post back.

[dmiley]

Ok, I checked the rear blades. I held the main blades and tried to rotated the tail blades. They seem to have a little "rough" feel when I first begin to try and move them (the feel from the motor maybe?) but I can't rotate them. I can however move them back and forth approximately 45 degrees in each direction. It just feels spongy like I'm stretching the belt if you get what I mean. Again, I'm not sure if that's normal or not or if it should feel solid and not move at all.

[widower]

spongy is just the tail belt stretching.

I'm wondering if your gyro is reversed.

In rate mode, does right rudder turn the heli right? If so, look at which direction the servo arm moved to cause the heli to turn right. If not, you need to reverse the rudder channel on your tx.

Now jerk the heli left. You should see the servo try to counteract the jerk by trying to turn right (so the servo should move the same direction as above). If not, you need to reverse the servo via the gyro.

Also, I just went through the exercise of re-setting up my tail. Something got out of wack. When the gyro first gets powered up, it will want to set the servo to the middle position. As the gyro initializes, it looks at the inputs from the rx to determine where center is. It took a few times to get it right, but the tx should have 0 for subtrim and trim. If not, set to 0 and re-bind the rx because the trims aren't seen by the rx until after the gyro has initialized. You will get to the point where turning on your rx with rate mode will keep the rudder servo in the middle. This is the starting point. Next, try firing up the heli in rate mode and trim/subtrim until it stays straight. I then used a caliper to measure the location of the tail slider. Then change the trim/subtrim back to 0 and adjust the mechanical linkage so the tail slider is in the pre-measured location.

Now the heli should stay dead straight in rate mode when you turn it on (and all rudder trims are 0). It took me aprox 4 complete turns on the control rod to get to this point.

Hope this makes sense.

[dmiley]

Hey all, thanks again for all the tips! Well, to be honest I feel kinda foolish but I solved the problem with the help of the great guy at my outstanding LHS. Seems my pitch on my main blades was messed up pretty bad. Once that was straightened out and a little tweak to the curves on the TX everything was golden. I got it home and right into a nice stable hover!

I'm glad to see there are forums like this that give great advice and help instead of bashing them for being new like I see so many places. Glad I found ya!

Ok, off to drain batteries on my now stable B400! :thumbup: