Eflight blade 400

[Josh Price]

I have a eflight blade 400 that i bang the sticks on all the time. I have never crashed it but the blades do have a little grass marks on them from landing (tail) or the ever so often upside down trimming on the taller small weeds. now the tail is shaking when I go to throttle hold what could this be from?

[ConRadical]

I'm interested to see this answer also since i have a Blade 400 arriving tomorrow. I'm not much of a heli guy but my guess would be the gyro gain.

[Hellsiege]

If the tail hit ever could be bent tail shaft. If your using stock 400 tail IMO they are very weak. It could also be the headspeed your running in throttle "up"(you said throttle hold but assuming you meant up... in throttle hold they should stop :) ) Depending on the twitch try dropping it down a notch in gyro gain... Could be a lot of different things though in reality... Is your 400 completely stock?

[n3m1s1s]

If the tail hit ever could be bent tail shaft. If your using stock 400 tail IMO they are very weak. It could also be the headspeed your running in throttle "up"(you said throttle hold but assuming you meant up... in throttle hold they should stop :) ) Depending on the twitch try dropping it down a notch in gyro gain... Could be a lot of different things though in reality... Is your 400 completely stock?

just to add to that turn your main blades by hand while looking at the tailblade head on if the tail shaft is bent you will see a slight (wiggle?) as the tail blade rotate :) to get rid of my tail vibrations after a couple of crashes i had to change that and the tail blade as they had little nicks in them made all the difrenct for my heli hope that helps

[Heli Jim]

Another thing to check is the blade holder for the tail blades. This is rather soft metal and can easily be bent in a tail rotor strike. The shaft may be straight but if the blade holder is bent, it can cause vibration.

[Josh Price]

yeap every thing is stock and just like it was out of the box.
thank you for the help I will take a look at it adn see what I find.
any of you going to ohio huck fest?

[exit44rc]

I would check the tail rotor shaft really close. It is sometimes hard to tell when they are bent because it can be very slight. But at high RPM's you'll see it shake a little. You could pull the tail blades and grips off if it will help you to see any runout.

The additional downside to a bent tail shaft is that it will make your tail servo have to work harder to move the tail blade pitch slider. This, I'm pretty sure, helped to cause my stock tail servo to fail.

[DismayingObservation]

Ooh, interesting...

My stock tail servo failed as well, leading as I believe to a chain reaction of ruined electronics. Thankfully, it was all replaced under warranty, but things could have been catastrophic if the ESC and/or tail servo failed in flight. I have no trouble with a wobbly tail now that all is fixed - the rotor seems to spin just fine - but it's definitely worth examining closer if any damage to the shaft is subtle.