Blade 400 left yaw on throttle up

[ReCuddjnu]

Hello guys, im new here so please bear with me. Just got my Blade 400 today and started going through RADD's. Here's my question though. I understand that a heli on start up is supposed to yaw left, but it seems that mine on throttle up is yawing left ALOT. is this normal? I noticed that on start up after plugging the battery in, the gyro locks in and aligns the tail rotor straight up and down, then after a few seconds it starts to push the tail rotor to the right. And then stays there.I have not moved the heli or the throttle. Is this normal? Is it a bad gyro? Not sure what to do, as I am new to a CP heli. Thanks for any help you can give.

[hawkman]

Hi there, welcome to the Forum...its a good one I assure you

The tail servo moving on its own? this could be the heading lock feature within the gyro...if there is a switchable gain on the radio then try to switch it the other way...and see if the servo creep stops.

You might have to adjust the gain, either on the gyro itself...a tiny dashpot screw or on the radio.

The Yaw problem could be that the tail rotor doesnt have the required pitch for its neutral point...sounds silly?

OK, with the heli on the floor and the rotor turning there will be some torque, the neutral point...ie servo arm central..needs about 6 degrees of pitch pushing the opposite way to the torque...so if you stand behind the heli...and the tail rotor is right hand side...the trailing edges need to point right...you can more or less guess the 6 degrees pitch..adjust till you get this.

You can move the servo mount, if its boom mounted, back or forwards to give you the required pitch...or adjust the control rod.

It sounds like the yaw is induced by this lack of pitch, and with the heading lock on this will not get dealt with as such....a badly set tail will show up under such conditions.

Hover about till the tail is not swinging either way...try not to use the trim on the radio.

The Blade 400 sounds like a good deal, have heard nothing but praise about it so far.

Got me a Trex XL 450HDE which is just a great machine, copes well with a hefty breeze and is just a pleasure to own.

On of my work mates has the 450SE, which is a different realm altogether...sweet running heli.

Rob

[hawkman]

Sorry, forgot to say.

Some gains work in heading lock from 50 percent to 100 percent...so anything less than 50 percent will be non heading lock...easiest way to see this is to hover the heli in a breeze...turn side on to the breeze and let the rudder stick center...if the helis nose goes into the breeze then its not heading lock...if the heli stays side on (drifting with the breeze) then heading lock is working.

You need to have heading lock on when connecting the power on some heli/gyro setups....the GY401 needs to be in this mode otherwise it wont work...the gyro still does its basic function.

Gain = sensitivity. so as you increase the gain the more sensitive the gyro is.

General rule is:

hover and fly about on a fresh battery, if the tail wags then land and decrease the gain a touch...go fly...if its not wagging then good...give the tail a quick left/right and see if the tail bounces/wags...if so land and decrease the gain a touch more.

You will see quite a bit on here about gyros and so on, but rest assured that even the most basic gyros today are very good, its not worth upgrading to a more pricey unit unless you are quite serious about the hobby and get into some stunt flying.

Rob

[ReCuddjnu]

Ok, well i haven't gotten to hover stage of RADD's school of flight yet, maybe i asked the wrong way so i'll try again.

In radd's on 1st/2nd battery you are just moving throttle up down to get a feel for it. If heli starts to yaw left (tail spin to right) it says you are appling to much throttle and to back down. Well, when i plug in my battery, the heli locks to the Tx, then gyro centers the tail rotor, and it stays, for about 3 seconds anyway. Then the servo starts moving the blades to the right as looking from the rear of the heli. And it wont stop moving them till it is almost all the way over. This is all without me touching the heli or the Tx. So when i apply any power to the heli it starts pirouetting on the floor(tail moving right) unless i hold the rudder to almost the complete right(3 o'clock position). What I am wondering is if this is normal(having to hold rudder at 3 o'clock) during take off(which im not close to yet) or is something on the gyro messed up? I messed with the gain, but brought it down from the 64% stock setting to about 53/54 % to have rotor centered(blades to right as you said) which helps alot, but will this then mess me up when I do get it in the air? Sorry if this doesnt make sense, any ?'s please ask and i'll try to explain better.

Thanks

[ReCuddjnu]

Oh yea, in case no one knows what i'm talking about when i say Radds's, here's a link:

http://www.dream-models.com/eco/flying-index.html

[hawkman]

I hear what you are saying, the slight tail rotor pitch of say 6 degrees still stands to reason, chances are that the tail rotor has zero degrees on it when its centered....and thats NOT correct.

The servo creep IS a hall mark of the heading hold thing...I have seen this before and while its not a menace I would re set the neutral point on the tail rotor.

You shouldnt get any swing on powering up to be light on the skids, like Radd has suggested...there might be a slight swing but to hold the rudder over like you have to is not correct.

Carry out the neutral point setting, it will make a difference...

I would make a hoop for the skids too...not sure what you are using but those ball things are ok..but a hoop is much better.
Make sure to get a small plastic ball and cut a slot in it...fit this over the bottom of the tail fin...just helps to stop the fin digging into the ground while you are learning.


Some models that are RTF are not always so, its common for them to be a bit out on some things...'test flown' might be just that....a quick hop in the air and then into its box ready for sale.

[ReCuddjnu]

sorry if I sound dumb. But should I set the neutral point using the gyro gain? Also, when should I set it? After it has drifted on start up? Thanks for your help by the way.

[ReCuddjnu]

sorry if I sound dumb, but when you say set the neutral point, do that using the gyro gain on the Tx? Also when I set neutral point, do I do it after it has drifted? Thanks for your help by the way.