hi

[Incredible319]

Hi all,

I am a newbie who owns a SJM 325 flown originally by a DX6i. Well, i mean at least could lift it off ground and hover it for about 2-5 min a few cm above ground.

A few weeks ago, i upgraded my tx to a JR9xII. I have managed to setup the heli again..everything seems ok except that the new settings for my pitch and throttle curve really suck (for me)

Now at half stick, my heli suddenly jumps up into the air when long ago, the transition to a hover was very smooth. I am slowly losing confidence in flying it because am afraid it may run out of control.

I also asked an experienced flyer to check it for me but he says its fine and he was able to keep it in stable hover in front of me.

i have set the heli for -2 to 10 pitch which should be relatively fine for a beginner .

Does anybody have any idea what's wrong? Is it too much throttle for that amount of pitch? I heard that more throttle equals more headspeed and therefore heli is more stable. So,in that case, is it because my pitch curve is not linear anymore that it causes that jump?

both my pitch and throttle curve are not linear. but that 'jump' is the one that scares me. I remember that when i was flying with my DX6i, the transition was very smooth and nice. I could keep it in the air at the height i wanted. But somehow i cannot remember the settings on my DX6i. Now the heli is very sensitive!

any advice is very welcome!

thanks for reading!

cheers

[J-S-Q]

Well this all depends on the rotor head being set up correctly (and the rest of your radio setup being ok) but curves something like these should get you a flyable heli if the head is set for zero pitch at centre stick (50% on your pitch curve):

Pitch: 40,45,50,75,100
Throttle: 0,80,90,100, or even 0,100,100,100

If you still have major problems then you most likely have an issue somewhere in your mechanical setup.

[J-S-Q]

Just thinking about it further... you say the heli now jumps into the air. I guess it's possible that with the DX6, your pitch curve was set to be more tame and not use the full pitch range of the head -you could perhaps try lowereing the top of the pitch curve which would make it less sensitive. You would have to experiment to see what works but you could try something like:
40,45,50,70,90
or
40,45,50,65,80

[Incredible319]

Originally Posted by J-S-Q

Just thinking about it further... you say the heli now jumps into the air. I guess it's possible that with the DX6, your pitch curve was set to be more tame and not use the full pitch range of the head -you could perhaps try lowereing the top of the pitch curve which would make it less sensitive. You would have to experiment to see what works but you could try something like:
40,45,50,70,90
or
40,45,50,65,80

hi J-S-Q,

sorry for my late reply!

thanks a lot for the advice! Indeed it could be possible that it was tamer on my DX6i but i cannot remember the settings at all to transfer to my new tx

at the moment i fly only on normal mode..no idle up

so my throttle curve is

pt L: 0
pt 1: 25
pt 2: 40
pt 3: 55
pt 4: 75
pt 5: 85
pt H: 100

and my pitch curve is

pt L: 37
pt 1: 39
pt 2: 43
pt 3: 50
pt 4: 66
pt 5: 83
pt H: 100

hope it helps..thanks a lot!

[Incredible319]

Originally Posted by Incredible319

hi J-S-Q,

sorry for my late reply!

thanks a lot for the advice! Indeed it could be possible that it was tamer on my DX6i but i cannot remember the settings at all to transfer to my new tx

at the moment i fly only on normal mode..no idle up

so my throttle curve is

pt L: 0
pt 1: 25
pt 2: 40
pt 3: 55
pt 4: 75
pt 5: 85
pt H: 100

and my pitch curve is

pt L: 37
pt 1: 39
pt 2: 43
pt 3: 50
pt 4: 66
pt 5: 83
pt H: 100

hope it helps..thanks a lot!

i shall try your recommended settings and see how it is like! i will let u know!

thanks

[J-S-Q]

Well just looking at your throttle curve, I'd say that is likely to be the root of your problem. It's definitely too low and ought to be something more like what I mentioned in my post above except obviously your radio has 7 point curves instead of 5 so it would be something like

ptL: 0
pt1: 70
pt2: 80
pt3: 90
pt4: 93
pt5: 97
ptH: 100

Your pitch curve looks fine though.

[Incredible319]

Originally Posted by J-S-Q

Well just looking at your throttle curve, I'd say that is likely to be the root of your problem. It's definitely too low and ought to be something more like what I mentioned in my post above except obviously your radio has 7 point curves instead of 5 so it would be something like

ptL: 0
pt1: 70
pt2: 80
pt3: 90
pt4: 93
pt5: 97
ptH: 100

Your pitch curve looks fine though.

hi J-S-Q,

thanks a lot for the advice..sure i will try that out

its slightly windy where i fly and i guess more headspeed will make it more stable..

i will keep u updated

[Incredible319]

Originally Posted by Incredible319

hi J-S-Q,

thanks a lot for the advice..sure i will try that out

its slightly windy where i fly and i guess more headspeed will make it more stable..

i will keep u updated

hi J-S-Q,

i tried the throttle settings you recommended and tamed down the pitch curve slightly!

the heli is now very stable..i hovered for about 5 min non-stop..great!

however, if i use a higher rpm, will it drain my battery faster?

thanks a lot for your advice

[J-S-Q]

Yes it will shorten your flight times to some extent but you just have to accept that really. Glad the curves have helped.