Test flight went well until.

[Kindling Maker]

Ok the Test flight went well until about 4 minutes into the flight. All was going great and the tail went to the right and the head speed really dropped off. The first thing I thought was a ESC over heat. Well I jerked the canopy off and the ESC was at 157 degrees. I let it set for a few minutes and went back out It hovered well for about 1 min and then it did it again. I landed well it was more of an Auto than a landing. I kissed the tail rotor that was it. Now I have a vibration in the head, again and the tail servo is drifting while it is setting still. What could it be I am at a loss.

[sparx-]

You bent the Tail shaft. I have found the B400 tail shafts are easily bent if you have a simple tail strike. Even the slightest bent will give you a vib as the tail rotor is spinning fast.

SPaRX

[JimLerch]

Sitting on the table, the gyro always seems to drift a little. When its in the air, (and warmed up) it might drift a little, but the gyro senses the motion and sends a signal to correct for it. Thus it canceled the drift.

On the table, it drifts, never feels the drift, and never corrects for it. End result is the servo ends up hard over after a few minutes.

With regards to your flight. Did you hear a change in power output when the tail went right (nose went left, same thing as if left rudder input)? If no change in power output, then you might have had a slippping belt. (nose left, tail right is often the responce to engine torque and lack of tail authority).

If the motor shut down, usually the tail goes left, and the nose goes right. IE the sudden loss of engine torque happened quicker than the gyro could move the tail servo to get rid of extra tail rotor thrust. Consequently the tail goes left, nose goes right (same as right rudder input).

So, which way did you tail go again? I ask as its odd for the TAIL to go right AND the head speed to drop off. If the tail went left, then ok...

[LockMD]

Did you install a BEC? Also, verify your belt is not binding or too tight.

[skigolfmike]

This sounds very similar to the ESC Thermal shutdowns I had. I ended up putting a bec on the bird and pulling the positive wire from the ESC servo connector.

If you have upgraded your servos and you're flying where it's hot, you might need a bec.

[Kindling Maker]

Yea the tail went left, and I could hear the motor spool down, And since I alreadyhave it apart again I will check the tail rotor shaft. Soory it took so long for me to chech this again but I had to work later last minght and did not get a chance to log on after we got done. Thanks for the advise. I can see a BEC in the future, it was only 95 yesterday, but I figure I am going to need one once it gets in the 110+ range.

[Kindling Maker]

Ok I pulled the Tail assy apart and eveything looks OK since the gear is made onto the shaft os there any way to check it to find out if it is straight? if it was a main shaft simpy rolloing it would tell me but with the gear on it there is no way that I can see to check it.

[GreenBar0n]

Hold the tail fin, spin it up lightly, and stare at the t/r shaft, if it's bent you should be able to see it. If it's a little blurry, not sharply defined, its got a warp or bend.


EDIT:safety first as always :YeaBaby:.

[sokal]

even the slightest bend will cause vibrations.
iv found the biggest vib culprate pull the boom supports off and check for security on the rod and the mounting arms seems they used cheap glue.
now for the tail servo the tail slider control arm will cause problems in the tail due to it weak mount design. check that it as straight as possible the screw is easily bent and will cause preasure on the tail shaft. just bent it out or replace the screw. hub mount put it on slightly then hub out as far as it will go then lock it down. will give u a lilmore in the tail.
also make sure the the main shaft and the tail shaft our 90 deg out from eachother
also belt tention to tight will caused loss of power and vibrations
belt should be right past the point were belt skipping doest occure.
hold the tail drive gear and try to turn tail shaft find the point it skips with a moderate amount of force and go beyond to were it wont skipp with the same amount of force.
when you check the tention it will seem loose to you but u will get half through with lil force. perfect tention. as iv promised vid will be done. just have to find time and have to take her back apart.

[Kindling Maker]

Ok then the main blades are striaght down the frame the Tail should be verticle, correct? Also I am going to change the Tail blades out, just on the chance I nicked one and threw them out of ballance. I have gone thru the tail and am doing a total restore on it again just to make sure I did not forget anything. I think it is a Thermal problem The ESC was 157 buy the time I got to pull the body off an take a temp on it. I think that I am going to order the BEC for it how hard are they to install? Thanks for all the help guys.

[skigolfmike]

You will need to do a little soldering. Basically you run the positive and negative input wires from the bec to the battery connector on the ESC. Then you pull the red wire/pin from the connector. You don't' need to cut the wire, just carefully lift the clip on the plug with a small screwdriver and pull the pin out. Then tape it back onto the other wires. Find a spot for the BEC on the frame, install and you're done.

One thing you will have to be aware of. If you change your setup and want to rebind, you will have to pull the esc connector out of the receiver and move the bec connector to the throttle position to open up the battery position to put the binding plug. A minor nuisance, but necessary.

[Kindling Maker]

I will have to order a BEC it will take 7 to 14 days to get here, one of those things about working in Iraq.