Up Wind vs Down Wind Turns - RC Groups
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Jul 08, 2013, 09:08 PM
Gone Flying
TechJunkieRC's Avatar
Discussion

Up Wind vs Down Wind Turns


I am trying to learn to be a better pilot. I do not have a club or instructor near me so I am doing this the hard way. I have read several posts about flight perceptions and miss perceptions. Basically the visual issues with the RC Pilot standing still while the plane is moving. I am not sure if this is just another one of the issues with perceptions or if this is more of an aerodynamic issue. Here is the situation:

I was flying one of my planes off of water on vacation. I was on the dock and my only option was to fly into and then with the wind. I took off successfully into the wind. When I went above the tree line I expected there to be more wind and there was. When I went to turn it was like the plane ignored my commands. I kept providing input until it turned and then, as you probably guessed it, the plane decided to really turn and nearly spiraled in. I was able to pull it out in time and fly on. On the down wind run when I went to turn back up wind the turn seemed normal, I moved the sticks the plane turned. What happened with the first turn? What caused it to seem to just stick there and then turn so violently? I assumed it had something to do with the wind speed but that doesn't seem to make total sense. The ailerons had air moving over them the same as they did down wind.

I really want to learn the right way and am genuine with my question.
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Jul 08, 2013, 09:40 PM
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dedStik's Avatar
Was the wind gusting or did it remain constant all day? Were you using more throttle due to the effects of wind? Did you increase the throw rates of the control surfaces?

The last two being my MO when flying in wind, I increase power and control surface deflection as needed.

Using very little deflection IE dual rates you may experience the aircraft not wanting to respond or responding sluggishly in that situation.

Another possibility is direction you didn't mention if the aircraft responded the same in both directions. Due to improper control horn placement on my control surfaces of some aircraft I've built I essentially built in a flaw where I'd have more throw in one direction vs the opposite IE rudder would extend further right than left meaning left turns would generally be slower and wider. While right turns were noticeably tighter.
Jul 08, 2013, 09:44 PM
Gone Flying
TechJunkieRC's Avatar
Quote:
Originally Posted by dedStik
Was the wind gusting or did it remain constant all day? Were you using more throttle due to the effects of wind? Did you increase the throw rates of the control surfaces?

The last two being my MO when flying in wind, I increase power and control surface deflection as needed.
I had the throttle at 2/3 as I was initially climbing to altitude and once I leveled off I had not pulled back since I was moving into the wind. I usually power back after the upwind turn. Not saying this is right, just seem to turn better when flying into the wind with a little more power. I had the surfaces on high rates due to the conditions. It was a little gusty at times but mostly steady.

I do have expo programmed into my transmitter. Could this have contributed?
Jul 08, 2013, 09:47 PM
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dedStik's Avatar
Expo is hard to say, I wasn't watching you on the sticks, only you know how much stick you were giving it. Since you are asking I imagine you were giving full input and were getting nothing.

Only time I've had controls not respond like that was in a stall.
Jul 08, 2013, 09:56 PM
Registered User
rcmaverick's Avatar
Quote:
Originally Posted by TechJunkieRC
Here is the situation:
I really want to learn the right way and am genuine with my question.
Did you use the rudder? Or just the ailerons. You will have to learn to use both especially in windy conditions. The reaction time lag can vary from plane to plane and from one wind condition to another. I would never maiden a new plane in windy conditions. It is all about feel and gaining confidence. I feel you are over thinking what happened.

Be sincere about your flying but not serious.

Jul 08, 2013, 10:04 PM
Registered User
I have had this problem b4 also. As dedstik stated, using 100% deflection made all the difference in the world. No change in my expo, just increased my deflection.
Going into the wind at speed normally results in immediate results. What plane are you flying?
Expo wouldn't play any part if you were full stick left or right, you would still be getting 100% of the control surface deflection that you have programmed into your radio. Only problem is, if you have 60% dialed in your radio then your plane won't bank as easily as it would at 100%.
Jul 08, 2013, 10:11 PM
You can't take the sky from me
cfircav8r's Avatar
The most likely cause was wind sheer (turbulence). You went from one wind speed/direction to another, abruptly, due to the natural wind break (trees). After that you were in calmer air. Normally with wind the problem is with your perception. On up wind when you start a turn it will seem to turn faster and sharper, because as soon as you start turning down wind your ground track will rapidly start moving towards the turn due to the drift down wind, and a turn from down wind it will appear to lag as the drift makes it seem to not respond immediately.
Jul 08, 2013, 10:24 PM
Drone offender FA377YHFNC
What you're looking at there is a really persuasive optical illusion.You're stretching the turning of the plane over a long ground track as the plane is carried along by the wind. This makes it look like it is not turning, although it is turning exactly as fast as it would with no wind.
Jul 08, 2013, 11:18 PM
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TechJunkieRC's Avatar
Quote:
Originally Posted by rcmaverick
Did you use the rudder? Or just the ailerons. You will have to learn to use both especially in windy conditions. The reaction time lag can vary from plane to plane and from one wind condition to another. I would never maiden a new plane in windy conditions. It is all about feel and gaining confidence. I feel you are over thinking what happened.

Be sincere about your flying but not serious.

No I was only using ailerons. I have been practicing the rudder for coordinated turns but I didn't do it this time.
Jul 08, 2013, 11:23 PM
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TechJunkieRC's Avatar
Quote:
Originally Posted by melloyello
I have had this problem b4 also. As dedstik stated, using 100% deflection made all the difference in the world. No change in my expo, just increased my deflection.
Going into the wind at speed normally results in immediate results. What plane are you flying?
Expo wouldn't play any part if you were full stick left or right, you would still be getting 100% of the control surface deflection that you have programmed into your radio. Only problem is, if you have 60% dialed in your radio then your plane won't bank as easily as it would at 100%.
I wasn't full left stick at first. I kept applying input trying to get it to turn. I was almost full left and then bam it nearly snapped over into a dive. I pulled it out as I was fortunately high enough. I was very surprised. It was like no turn and then bam nearly spinning down. My expo is 35 I believe for the ailerons. Some use more but this seems right for me.

Quote:
Originally Posted by Rockin Robbins
What you're looking at there is a really persuasive optical illusion.You're stretching the turning of the plane over a long ground track as the plane is carried along by the wind. This makes it look like it is not turning, although it is turning exactly as fast as it would with no wind.
I wondered if it wasn't as you describe. I plan on getting high and learning how it appears in the air with the same input for both turns.

BTW: I am flying the Parkzone ICON A5. Not an aerobatic plane by no means but much more responsive than my Bixler 2 when it comes to quick turns.
Jul 08, 2013, 11:27 PM
Gone Flying
TechJunkieRC's Avatar
Quote:
Originally Posted by rcmaverick
Did you use the rudder? Or just the ailerons. You will have to learn to use both especially in windy conditions. The reaction time lag can vary from plane to plane and from one wind condition to another. I would never maiden a new plane in windy conditions. It is all about feel and gaining confidence. I feel you are over thinking what happened.

Be sincere about your flying but not serious.

I tend to be a little too type A I guess. Just concerned that I just about planted it and not knowing if the issue was the wind, plane or pilot bugged me. It appears it was the pilot. Not really surprised!
Jul 09, 2013, 01:31 AM
You can't take the sky from me
cfircav8r's Avatar
If it was truly not responding and then suddenly responded then turbulence is the culprit. If you are not sure how much you were giving it and how it actually responded then it is likely you were misinterpreting what was happening, and an experienced set of eyes would have been helpful. Gusting will cause control issues but it will make little difference what direction you are going and will be transient. Steady wind will not affect the control responsiveness no matter what direction you are going, but ground track, and ground speed will vary greatly depending on wind speed and direction. This in turn is what causes the confusion if you do not fully understand the physics of flying in wind.
Jul 09, 2013, 05:02 AM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Sounds to me simply that you had insufficient flying speed. If you were climbing steeply your airspeed probably dropped. When you get near to stall it's normal for the ailerons to be unresponsive, then as the airspeed dropped further and you added more aileron you suddenly stalled causing a wing to drop and the model snap around.

All sounds pretty much what you would expect.

The lesson here is that if the control response on your plane becomes 'mushy' that's almost always a sure sign that you are approaching a stall. The corrective action is to increase power and/or add some down elevator to get the nose down.
Last edited by JetPlaneFlyer; Jul 09, 2013 at 06:43 AM.
Jul 09, 2013, 05:32 AM
Beware Of The Shills !!!
Sounds like it reacted pretty normally to the situation. If you're going along in the car say doing 60mph, hang your hand out of the window horizontally and you hand going into the wind cuts through the air and almost doesn't want to move from that angle which is like the resistance of the plane not wanting to turn.
Then angle your hand either up or down and it very suddenly wants to head either up or down and it's a very strong pull.
One minute your plane is heading straight at the wind like a dart and cutting through the wind the next it's sideways on where not only are the ailerons wanting it to turn but now the wind has caught the wings and is pushing it round as well.
Other thing to factor in, as you head into the wind it increases the planes lift as the wind's passing over the wings, as you turn and have the wind behind it decreases the lift so higher throttle is needed to compensate, I increase throttle during a turn into the wind to head downwind.
That said I made the exact same mistake the other day doing a harrier 3 foot off the deck, turned so the wind was now behind, had some wing rock and just not enough airspeed and ended up snapping the rudder / stab off, flies better now after the repair though as I built it back straighter than it was before
Jul 09, 2013, 06:26 AM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Quote:
Originally Posted by Witterings
One minute your plane is heading straight at the wind like a dart and cutting through the wind the next it's sideways on where not only are the ailerons wanting it to turn but now the wind has caught the wings and is pushing it round as well.
Other thing to factor in, as you head into the wind it increases the planes lift as the wind's passing over the wings, as you turn and have the wind behind it decreases the lift so higher throttle is needed to compensate, I increase throttle during a turn into the wind to head downwind.

No, this is the classic 'downwind turn' myth.
The (steady) wind you and I feel on the ground has no aerodynamic effect on a plane in flight whatsoever. Aerodynamically there is no difference between a turn 'into wind' and a turn 'downwind'. The airspeed of a plane flying 'into' and 'out of' the wind is identical, throttle does not have to be increased to fly downwind.
The only 'wind' that a plane 'feels' in flight is it's relative wind in relation to the air it's flying through, relative wind is equal to airspeed and has nothing to do with the wind you feel on the ground.

Note: Previous paragraph assumes a 'steady state' wind. Gust, turbulence and wind shear are different, they do effect a plane regardless of what direction it's flying in.


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