Up & Down

[Kennyyoli]

After completing my build I was just happy the thing flew. Now as my skills are progressing, I am noticing some things that aren't quite right. The major one is keeping the heli level. If I leave the throttle stick alone at a hover, the heli will rise and fall pretty dramatically. To keep a level hover is almost impossible. I can be hovering at 3' and it will come down almost all the way to the ground.
I think I may have some interactions that is causing this, but I cant pin down exactly whats going on. I've notice that if the heli is coming down, and I make a move with left aileron it sometimes bounces back up.
At any rate, how level should the bird stay if I get to a hover and leave the stick alone, barring winds etc... ?
Thanks in advance for the help

[N017RW]

Originally Posted by Kennyyoli

At any rate, how level should the bird stay if I get to a hover and leave the stick alone, barring winds etc... ?
Thanks in advance for the help

Not at all (stay level vertically that is). You will also have the leftward translation tendency as a result of tail rotor thrust when hovering. So you'll need to add a wee bit of right cyclic which will cause the heli to tilt to the right.

At 3' above ground you are flying in your own rotorwash not to mention ground effects so get a little higher. Counterintuative when beginning but it gives you more time to react befor hitting the ground.

To help this (reduce sensitivity) you can reduce pitch mix % in the swash mix menu. You can do the same for elevator and aileron or add expo to reduce the sensitivity until you learn to soften your inputs.

This is all normal so just be glad your in the air and bring it down controllably (softly).

[Kennyyoli]

I probably didn't explain myself very clear..
It's not the levelness I am concerned with. Its sustaining altitude in a hover. It's coming way down, then back up with no input to throttle/pitch. It will fluctuate 3 or 4 feet of altitude. It "feels" like left aileron input is adding pitch and making the heli go up? I could be wrong about that.

[fast400]

maybe try going into your pitch curve settings and upping it by 5 in each position?
or the swash mix menu, try adding 5 clicks to the pitch setting.

[BaconRaygun]

Originally Posted by Kennyyoli

I probably didn't explain myself very clear..
It's not the levelness I am concerned with. Its sustaining altitude in a hover. It's coming way down, then back up with no input to throttle/pitch. It will fluctuate 3 or 4 feet of altitude. It "feels" like left aileron input is adding pitch and making the heli go up? I could be wrong about that.

Do you hear the motor changing RMP?
What is your head speed?
Or if you don't know then your throttle curve and pinion will help.

Also, the batteries... What batteries (specs please) are you using?
And how have you been treating them?
If you mistreat LiPo's they will degrade fast, if your pack is not producing adequate voltage then you may experience something like this. My heli does exactly what you describe when I am hitting LVC.

[Kennyyoli]

Originally Posted by Vicovaludemero

Do you hear the motor changing RMP?
What is your head speed?
Or if you don't know then your throttle curve and pinion will help.

Also, the batteries... What batteries (specs please) are you using?
And how have you been treating them?
If you mistreat LiPo's they will degrade fast, if your pack is not producing adequate voltage then you may experience something like this. My heli does exactly what you describe when I am hitting LVC.

I don't hear the motor changing RPMs. I am running the Align 450M motor with a 13 tooth pinion, & the Align 35 ESC.
My pitch curve in "normal" is 40-44-50-75-100
Throttle curve is 0-45-70-78-90
The lipos have 10 charge cycles through them, always balance charged. They are Turnigy 2200mAh 20-30c packs. The problem seems to happen no matter what pack I have in..

[fast400]

strange,
i run 0,25,50,75,100 on normal pitch curves, and the same for normal throttle curves.
i have some up and down movement, but not alot. i do know the more jerky you are with the sticks the more the heli will bounce up and down.

[Kennyyoli]

Originally Posted by fast400

strange,
i run 0,25,50,75,100 on normal pitch curves, and the same for normal throttle curves.
i have some up and down movement, but not alot. i do know the more jerky you are with the sticks the more the heli will bounce up and down.

I don't think its because of jerky movements. It does it with my thumb completely off the left stick. ??

[fast400]

Originally Posted by Kennyyoli

I don't think its because of jerky movements. It does it with my thumb completely off the left stick. ??

ok,
but you use the right stick to make the heli shift/bank left and right and forward/reverse.

did you set up the pitch in the blades with your pitch settings or with the linear 0,25,50,75,100 curve?

[755 robert]

Try a flat TC, 0-45 80-80-80, or 0-45-75-75-75 ..this may smooth it out...

[Montana]

+1 on the flat throttle curve. I use 0-90-90-90-90, but I don't do any kind of 3D. I think there is also a psychological benefit to the motor making a consistent sound, too.

[BaconRaygun]

Have you crashed it?

[Kennyyoli]

Originally Posted by Vicovaludemero

Have you crashed it?

No, not yet.. Just got it put together

[BaconRaygun]

hmm... How high are you hovering it?
'eye level'? Or lower?

Was there any wind?

Judging by your gearing and throttle curve I would say you already have a fairly low head speed... It may be a good idea to either do a flat curve as suggested or at least something like 0-70-70-80-90.


Sorry for all the questions.

[Kennyyoli]

Originally Posted by fast400

ok,
but you use the right stick to make the heli shift/bank left and right and forward/reverse.

did you set up the pitch in the blades with your pitch settings or with the linear 0,25,50,75,100 curve?

Set the pitch to 0 at midstick, witch servos centered.

[Kennyyoli]

Originally Posted by Vicovaludemero

hmm... How high are you hovering it?
'eye level'? Or lower?

Was there any wind?

Judging by your gearing and throttle curve I would say you already have a fairly low head speed... It may be a good idea to either do a flat curve as suggested or at least something like 0-70-70-80-90.


Sorry for all the questions.

It was happenoing indoors, so wind was not an issue. Hovering around 4'

[fast400]

Originally Posted by Kennyyoli

Set the pitch to 0 at midstick

you used the linear 0,25,50,75,100 when you set the pitch correct?
then changed the curve to your current settings?

[Kennyyoli]

Originally Posted by fast400

you used the linear 0,25,50,75,100 when you set the pitch correct?
then changed the curve to your current settings?

yes

[BaconRaygun]

Originally Posted by Kennyyoli

It was happenoing indoors, so wind was not an issue. Hovering around 4'

I think that may be part of your problem... indoors like a garage right? and a 450 sized heli. Even though you were 4 ft up your heli creates currents that bounce off the walls, floor and ceiling. Unless were talking a gymnasium or sports hall...

Try it outside on a calm day/afternoon, I bet you wont be bouncing around.

[Kennyyoli]

Originally Posted by Vicovaludemero

I think that may be part of your problem... indoors like a garage right? and a 450 sized heli. Even though you were 4 ft up your heli creates currents that bounce off the walls, floor and ceiling. Unless were talking a gymnasium or sports hall...

Try it outside on a calm day/afternoon, I bet you wont be bouncing around.

I should be able to get outside tomorrow, so I'll try that and see if it goes away. Thanks