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View Full Version : What makes some rc helis more or less sensitive to the wind ?


hareedy
06-17-2012, 09:12 PM
I have been flying rc helis for 6 years now
And I noticed through flying lots of them that some are less sensitive to the wind than others
For example the outrage fusion 50 is less sensitive than my logo 600
To tell u the truth the outrage is much more stable in the wind than the logo 600
Off course I mean 3d flying ( funnels , tic toc ....etc )


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desertstalker
06-17-2012, 11:55 PM
How heavy are the two helis?

Like planks disc/wing loading affects stability in the wind (higher is better). For a heli more weight also makes a difference (regardless of disc loading) as there is more inertia for the wind to overcome.

Assuming they are both FB, its less of an issue with FBL helis.

hareedy
06-19-2012, 10:28 PM
Thanks for replying
Both my logo 600 which weigh 4.2 kg with 623 mm edge blades fbl and my goblin 700 which weigh 5.1 kg and the sab 690 mm are so sensitive to the wind but the outrage fusion 50 is so stable in the wind that I couldn't believe it when I tried one although its almost the same weight as the logo and it uses the same blades and that's what got me to wonder about the design



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kimmik
06-20-2012, 05:50 AM
Since they are fbl, what differences are there in setup? Ie gyro, servo and settings.

hareedy
06-20-2012, 08:51 AM
All the same servos jr 8717 working on 5.5 volts and all vbar with almost identical setups


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hareedy
06-20-2012, 08:52 AM
The outrage and the logo runs at 2200 hs
And the goblin runs at 2230 hs


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kimmik
06-20-2012, 09:10 AM
That shouldn't be then, assuming both gains were optimized.

It's possible that damping design differences are the cause. Also if one Heli has perfect phasing and the other doesn't, that can be a cause too. My Tdr was jittery and a bit hard to hover precisely until I optimized the phasing for the specific blades.

CeeveeSiN
06-20-2012, 09:19 AM
Thanks for replying
Both my logo 600 which weigh 4.2 kg with 623 mm edge blades fbl and my goblin 700 which weigh 5.1 kg and the sab 690 mm are so sensitive to the wind but the outrage fusion 50 is so stable in the wind that I couldn't believe it when I tried one although its almost the same weight as the logo and it uses the same blades and that's what got me to wonder about the design



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Err wait a sec you said your Goblin 700 is sensitive in the wind?

that has to be FBL setup.. as nothing short of a 50+ MPH wind is going to move a 700E anywhere you dont want it to go..

with a properly setup Vbar 5.2+ wind is non existant on any 600-700 heli for the msot part.

We fly in sustained 30+ down here during the spring and early summer and none of my large birds fight the wind at all..
hell I fly the 450 in 25ish winds with no issues.

hareedy
06-20-2012, 05:41 PM
Ok Here is a video to show what I am talking about
It was a 35 km+ wind and gust up to 40 something
At the end of the funnel u will c that the heli drifts like there is no tomorrow

youtube.com/index?desktop_uri=%2F&gl=EG#/watch?v=USnRwUogcK8



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hareedy
06-20-2012, 05:42 PM
Tomorrow I will attach my vbar file any comments will be appreciated


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hareedy
06-21-2012, 08:10 AM
That shouldn't be then, assuming both gains were optimized.

It's possible that damping design differences are the cause. Also if one Heli has perfect phasing and the other doesn't, that can be a cause too. My Tdr was jittery and a bit hard to hover precisely until I optimized the phasing for the specific blades.
what do u mean by (optimized the phasing for the specific blades.)
can you please explain ?

kimmik
06-21-2012, 08:35 AM
Different blades lead or lag different amount. The head has fixed phase, usually 90. This means on one set of blades, if elevator servo moves, the Heli perfectly moves in pitch only. Gyro corrections are thus applied perfectly by the blades, achieving rapid stabilization of a destabilizing event eg wind

On a different set of blades that lag say 3degrees, here's what happens in simplified explanation.

Elevator servo moves, Heli moves cosine3 in pitch, and sine3 in roll

Now gyro has to correct the roll error by using aileron swash

But then the Aileron swash actually causes a bit of pitch.

So what happens is a wobble, or precession movement of the head or body with destabilizing events. Not only does it slow down the recovery of control, but also limits the max gain usable, component wear.

If you do some quick stabs of either collective or rudder, or do a rapid stop, and see a wobble in either head or body, that means the phase is out a bit.

My experience with the Tdr is, at 4deg out, the Heli feels a bit unsteady. Piros wobble noticeably rather than being flat. Gain can't be turned high before body wobbling even at hover. Now that it has 4deg of swash lead (ie blade lags 4deg), perfect flying machine.... I'm in total awe of it!

kimmik
07-06-2012, 08:06 AM
Any update?

BladeBender
07-19-2012, 12:28 PM
I have been tinkering with an HK450V2 NOBAR projekt with a little bit of success. I am still in the "hunting the best blades" phase (no pun intended) and was curious as to how i determine the lag of a particular set of blades? This way I can optimize the phasing for each set tried. Im using an old school mechanical swash driver, seperate from rotorhead, so phasing adjustments should be possible. On a side note: does blade lag occur with any noticeable effect on the tail (i realize they woud both lag the same amount, if at all).

ehernan3
07-23-2012, 12:04 PM
Different blades lead or lag different amount. The head has fixed phase, usually 90. This means on one set of blades, if elevator servo moves, the Heli perfectly moves in pitch only. Gyro corrections are thus applied perfectly by the blades, achieving rapid stabilization of a destabilizing event eg wind

On a different set of blades that lag say 3degrees, here's what happens in simplified explanation.

Elevator servo moves, Heli moves cosine3 in pitch, and sine3 in roll

Now gyro has to correct the roll error by using aileron swash

But then the Aileron swash actually causes a bit of pitch.

So what happens is a wobble, or precession movement of the head or body with destabilizing events. Not only does it slow down the recovery of control, but also limits the max gain usable, component wear.

If you do some quick stabs of either collective or rudder, or do a rapid stop, and see a wobble in either head or body, that means the phase is out a bit.

My experience with the Tdr is, at 4deg out, the Heli feels a bit unsteady. Piros wobble noticeably rather than being flat. Gain can't be turned high before body wobbling even at hover. Now that it has 4deg of swash lead (ie blade lags 4deg), perfect flying machine.... I'm in total awe of it!

So how do you correct a situation like this(4 degrees out of phase)? How do you measure it in the first place?

kimmik
07-23-2012, 01:51 PM
First make sure your fbl is perfectly aligned to frame

Then, start with 0deg phase, which is default, turn the cyclic gain up until you have wobbles at hover. If the wobble is single axis only, usually airleron, then no phase adjustment needed.

If the wobble is an ellipse or circle, then correction is needed. Usually advancing.

ehernan3
07-23-2012, 11:50 PM
First make sure your fbl is perfectly aligned to frame

Then, start with 0deg phase, which is default, turn the cyclic gain up until you have wobbles at hover. If the wobble is single axis only, usually airleron, then do phase adjustment needed.

If the wobble is an ellipse or circle, then correction is needed. Usually advancing.

Ok, bear with me: HOW, exactly, does one adjust the phase? It's not clear if this is something in the radio, the BeastX or the mechanical setup. I've never run across such an adjustment in any of the manuals for these three systems(radio, BeastX or heli).

kimmik
07-24-2012, 02:47 AM
Skookum has a setting. It's a fbl adjustment. Vbar too I'm sure, no

kimmik
07-24-2012, 02:48 AM
Not sure about 3gx or bx

gothicbunny
07-24-2012, 03:02 AM
With the beastx you can adjust the phase with the micro settings software. You will need the USB adapter.