somthing to get rid of tail wag

[Tele]

I decided to try out an idea about the gyro postition and tail wag on the hornet.

My theory was that due tot gyros picking up only angular displacement that you could de sensitise the gyro by moving the gyro further away from the main shaft.

My inital test show that this is the case ..my FBL hornet ( which is flying great now..even did some fig 8's! ) I moved the gyro from behind the main shaft to out the front of the heli ..this allowed me to move the gain from about 5% to about 30% on the gyro.

I would strongy like to hear od any other gain settings and positions of the gyro.

cheers doug

[Tele]

oh yeah if you recognise the blades ..yes they are the century CP blades. I took out the 1.9 g of lead they had in the tips and replaced it with about 4.3g of lead for the flybarless setup.
they fly great.!!!

[ammo]

Erm, the angular change that the gyro will sense is the same no matter where u place it. the important thing is the amount of vibration that the gyro is subjected to, resulting in it constantly over-correcting wrong signals, leading to the idea that the gyro is too sensitive.

[D.Yeo]

Hey doug i was giving the matter some thought too, before i bought the hornet.

I was thinking though that gyro being at different distances from the centre of rotation should not be a factor of angular displacement. assuming the rotating arm does not deform ( since it's the heli in this case i sure hope not ! )

Seat of the pants, i think our minds are blending in rate of motion with angular change.

But what i got stuck at was wonderign if the rate of angular change was the same.

It's got to be though.

after reading yuor post i've started wondering again haha

What i'm thinking now is it improves the gyros ability to respond and give more precise corrections that's why you can raise the gain on your better placed jr.

Let's all wonder why though ! an explanation is needed

[D.Yeo]

Ah i thought it through some more and i got it.

all along we're forgetting that the gyro senses the entire systems angular rotation only through reference to it's own rotation.

In free space the gyro mounted further out is rotating about itself slower thatn one closer in.

So mounting the gyro further out means as the heli rotates about it's centre of rotation the gyros own rate of rotation is much lower and so it's registered reading is consequently lower.

i think the relationship between the gyro's own rate of rotation and the helis rate of rotation would be thus a negative exponential curve that intersects the x axis at 1 , approaches the y axis to infinity,and is reflected across the x axis, when X represents the helis rate of rotation and y represents the gyros own rate of rotation.

When the gyros centre corresponds with the helicopters own the relationship is 1: the rate of rotation of the heli is equal to that of the gyro. As the mounting length increases the relationship changes as i discribed.

So when we have a helicopter tail boom that approaches infinite length and mount the gyro on the end, the relationship of the two
will consequently approach 0 where the two are no longer related


er this makes sense to me but it might not be the best way to describe it, and this big enlgihtenment thing to me might also be very obvious to veryone else so if it is er...sorry

[Tele]

Originally posted by D.Yeo

all along we're forgetting that the gyro senses the entire systems angular rotation only through reference to it's own rotation.

In free space the gyro mounted further out is rotating about itself slower thatn one closer in.

So mounting the gyro further out means as the heli rotates about it's centre of rotation the gyros own rate of rotation is much lower and so it's registered reading is consequently lower.

i

yes you have it ..the angular displacement is larger but the angular distance ( arch) is the same. so in basic terms you are giving the gyro a differnt ratio of sesentivity..somthing,like using a duel rate on the radio. your high point on the gyro will not be as high as if you were able to mount it near the shaft but then who has ever got their gyro on their hornet abouve 80%

hahahhaha

this way you can have a higher setting on the gyro ..less over reaction ( ie tail wag) and an easier mounting ..... vibrations aside.

[MicroHeli-Nut]

Doug.


I'm running 125% on my MS gyro..... and i mount it behind the main shaft. I support your findings 100%.

When i was running the Feda, I was able to mount the RC mart gyro right beside the main shaft..... the holding was superb!

[Super-Hornet]

Hi all

I haven't take the maiden flight for my Hornet II yet but when I run it with feet tied down, I notice the tail servo is twitching. I tried different sensitivity of gyro and still the same.

Then I do an experiment by connecting to bigger servo (from pico to naro) and the twitching is gone regardless of what sensitivity of gyro and now my gyro is just behind the main shaft.

Note: Pico servo size is like those made in china or those VS-6. It is using coreless motor and therefore it is the fastest for servo series. Maybe due to the size is small, it cannot use ferrite motor. Due to it is coreless motor, the torque is very low as compare to ferrite motor like those HS-55 or GWS Naro servo. If changing from coreless motor to ferrite motor servo type fix the glitching, then it could be either pico servo is too weak (unless u put servo near the tail propeller area) or coreless motor suffer glitching from Gyro o/p signal (Need noise filter?)

Super-Hornet

[MicroHeli-Nut]

Took apart my tail.... Tail wag comes from twisted torque carbon shaft from the piro dance i did on my table Well it ended up hitting the Tx.

Super,

Fit everything up and go fly first [ i mean hover] .....

Then u can tell if anything's amiss..