Miserable day...losing faith

[cjcj1949]

The gyro isn't really a gyro. That is is doesn't use a gyro to do anything. It's an anguler rate sensor with some electronics to make it look as though it knows where it should be pointing. An angular rate sensor just measures how fast the tail is turning. Just turn, nothing to do with movement. The sensors are not very accurate and give different outputs when you first switch on. To make this work they measure the output for a few seconds after switch on and assume that this means zero turn. That's why you must keep it still at switch on. This is called calibration which sounds better than bodge the sensor. After this, if the heli is in hold mode it measures the turn that happens and how long the turn lasted. The electronics then works out how many degrees the heli has turned. It then sends the opposite turn to the servo until the rate of turn has lasted long enough to get you back to where you started from.

When the heli is in the air this works ok, but when on the ground it is not so good as the heli doesn't turn very well on the ground, or when being carried. This builds up errors. If you switch into rate mode just before take off this will reset the gyro and it will not turn to the side. Or put the heli in it's final position before switching on.

[Gibbo73]

Again, thank you. However, the yawing left occurs in hover even when I plug in and set up properly ie. TX on, plug in battery, set down immedeatley and wait for it to innitialize...it just doesnt make sense to me...this is when the nasty vibration/wag starts, as I yaw back around to the right...it's like the heli is fighting the command. As soon as she's tail in and I let off the stick input, back round to the left she'll go...*inserts Twighlight Zone music*

[askeys_heli_madness]

Re: Miserable day...losing faith

Does it keep yawning left I.e will it keep going round in a circle if you let it or does it stop at 45 degrees as you have said in other post?

[nobbycopter]

Miserable day...losing faith

Hey Gibbo...you at Clyro hall tomorrow? If so I'll pop over and give it a look over I've probably got a spare servo and gyro we can try...sorry not been over since the first time but been really busy

You said there's a bad vibration? That could cause the gyro to throw a bit if a wobbly as they don't like vibes...anyway I'm sure we can get it sorted for you

[tim critchley]

So I knew I had a ******* tail servo, thought the tail output shaft and main shaft was shot(bad vibrations) so I bought new. Just fitted the new bits...servo is just as shot brand new out of box, and still have a wobble/vibration in the head...

Fed up. Need a club to join but there are no heli clubs near me.

Today is a sad day

hi there mate where in wales are you ? our club is about 15 miles from chester if your near or fancy a drive to the club i will have a look at it

[cjcj1949]

Best for people to have a look. Too much guessing otherwise.

[Gibbo73]

Thanks everyone. Not feeling half as downhearted as I was...Cinderella will go to the ball

[Gibbo73]

Does it keep yawning left I.e will it keep going round in a circle if you let it or does it stop at 45 degrees as you have said in other post?

It just stops and sits roughly 45 degrees nose left, and will return there after Ive yawed back to the right. It's like the HH locks nose left, not straight tail in.

[cjcj1949]

You have probably moved the heli after or during switch on. HH doesn't know anything about absolute position, it just looks as though it does. The only position it knows is the position at switch on. If you have a faulty gyro it may drift due to changes in temperature or if your rudder trim is not central. Switching into rate mode just before takeoff will zero the error. I'm assuming that you can point the heli in any direction and leave it there once flying.

[Mark_T]

There is nothing special about the position at switch on, the moment you make a rudder input, it is forgotten.

The normal small rudder inputs you would make on take-off cancel any 'error' immediately.

[Gibbo73]

I'm assuming that you can point the heli in any direction and leave it there once flying.

Nope :-( wherever I point it when in the air, around she comes, nose left...and no, I dont move her, I'm very careful to plug in, and leave it until she's set, then I take off from that same position...it really is weird.

Not able to get to test atm, but will post results next time I do.

Cant thank you guys enough for spending the time in this thread to help, cheers.

[Mark_T]

Having trouble thinking of anything that would cause a precise and repeatable change such as you describe.

Vibrations should cause a steady and continuing drift, not a change then a stop.

This shouldn't be it either, but do check that you have no trim set on the rudder channel.

[SaneAdam]

Could the tail servo not be going back to centre properly? Or it is going back to what it thinks is the middle? Sounds like its a tail setup issue

[Mark_T]

Could the tail servo not be going back to centre properly? Or it is going back to what it thinks is the middle? Sounds like its a tail setup issue

This sounds more like it is just overshooting the stop position but why and why always in the same direction?

[Gibbo73]

This sounds more like it is just overshooting the stop position but why and why always in the same direction?

The 6 million dollar question! :-)