gyro help

[stevek32]

hi guys.
i have fitted a gy520 following this guide

Futaba GY520 Programming Basics - Part 2 - YouTube
but the trouble is in rate mode when i spool it up it piros wildly to the right (tail in),

in hh mode its fine.

any ideas guys i've checked everything the right way around if when its piroing i give opposite tail it spins wildly right until i release it then goes back spinning right?.

i cant get it to hover in rate mode is that the best way to learn in also?


thanks

[sacko]

You need to adjust the linkage rod in rate mode.

Then reset it up again in HH mode.

[stevek32]

You need to adjust the linkage rod in rate mode.

Then reset it up again in HH mode.

confused? the tail is neutral pitch in rate and hh ,servo arm 90%

[sacko]

If you have 0 pitch, how is the tail meant to hold?

[stevek32]

If you have 0 pitch, how is the tail meant to hold?

I used sub trim in the tx menu and it didn't do anything made it worse?, I'm confused I thought because of the torque rotation of blades the tail will obviosly try and follow!, but with hh mode the tail should move against this to correct it?, so by putting opposite pitch on it surely that's confusing the gyro in the fact u have given it opp pitch but heli giving rotation pitch?

[sacko]

Yu shouldn't be using subtrim o the rudder.

If you are flying in rate mode, you should look to put about 6-7 degrees of pitch on the tail blades to counter the torque.

HH corrects this for you.

[stevek32]

Yu shouldn't be using subtrim o the rudder.If you are flying in rate mode, you should look to put about 6-7 degrees of pitch on the tail blades to counter the torque.HH corrects this for you.

Ok I sort of understand?, so say I'm flying tail in (tail nearest me?) So as I said heli lifted and spun the tail right, which way do I adjust pitch?, is the slider got to be nearer the tail or nearer the blades? And also why can I not use sub-trim?, I did try today with slider nearer tail but using sub trim and it piro'd to the right Thanks for helpin me on this paul I apprieciate itSteve

[del19_82]

Using subtrim on the tail means the gyro will see this as stick movement on initialisation and cause you no end of bother while trying to fly . To sort your issue you need to adjust the tail so if the Heli is piro'ing right you need to put in 6/7 degrees of left rudder to counter that, i can't give you exact lengths because you will need to make fine adjustments but 6/7 degrees is a good starring point.


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[stevek32]

hi dez i followed this;
http://www.youtube.com/watch?v=_H2VRdUSt7A

it seemed ok?.

so when you say i need to put pitch on left rudder is that when i move stick left or when i move it right?, soz i just cant get my head around tail rudder i.e stick left tail right etc,

also i dont understand i thought the gyro would sense the heli spinning right and put opp tail pitch in to hold it still, because in rate mode when i move tail, rudder adjusts until its back to its original position..... so i thought if heli tried to turn pitch would be applied to correct spin?, i thought it would be the same in hh mode?, it span right really really fast? i thought gyro was reversed but checked and it seemed ok when i push heli tail away from me control bar went back and vice versa?....

[sacko]

Rate mode is directly linked to the stick movement.

HH will correct the tail for you.

Stick left = Nose left
Stick right = Nose right

In rate mode, if the heli spins nose left, it needs right rudder to correct for it. An easy way to adjust is to see what way the slider moves when you give it right rudder...

...then adjust the linkage rod a couple of turns so that slider moves towards the position you looked at.

[stevek32]

so why do you reckon it still spun right i know i had a sub trim on it but it was really fast and going by what you said above i had it adjusted correctly all be it with trim,

[del19_82]

It sounds to me like your not sure what end of the Heli to fly (ie nose or tail). Always fly the nose so left stick means nose left, right stick means nose right.

Pauls instructions are spot on for setting rate mode and is how I would do it!


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[stevek32]

Ok thanks guys I have set the heli mechanically by altering the slider bar but now its binding on right rudder!, and I,ve been into gyro setting to try and reduce full right rudder but it won't let me adjust it back far enough?, will it matter that its binding on full right? Full left is fine.

[cjcj1949]

You need to mechanically adjust the linkage so that when the tx control is in the middle that the servo arm is at 90 degrees to the linkage and that the adjuster on the tail spindle is rougghly in the middle and the angle of the tail blade should be about 6 degrees. If you look from the top the tail blade should be pointing at a point about 6 inches to the right of the heli undercarraige.

The reason for this is that helis are not really meant to fly. By that I mean that there are bodges that are needed to keep the heli hovering.

The fact that the main rotor turns to provide lift means that the body of the heli will turn in the opposite direction. The tail rotor is there to stop this happening. The tail rotor needs to produce a force to stop the heli turning. It cannot produce a force if it is at 90 degrees to its rotation. It needs to have a small angle of incidence to do this of about 5 degrees. If you look at the top blade from above it should point to the right. The slider on the tail axle should be roughly in the middle at this setting, so that the left and right net or resultant forces will be equal. (This is only roughly true but a good starting point)