Ailerons ineffective in high wind?

The old Downwind Turn fallacy raises its head again. The airplane, flying in the airmass, feels no acceleration or deceleration when turning into or out of the wind. We train students under the hood for instrument flight; they can't see outside, can't see anything but the instruments in front of them, and when we fly in strong winds we can have them turn circles and they will neither feel any acceleration or deceleration nor see any airspeed or altitude variations. Yet the airplane's track over the ground will be anything but circular. The airplane has plenty of time to adjust while in the turn, and the only way an airplane would feel any increase or decrease of lift in a turn would be if it could turn instantly, without any turn radius or time in the turn. Inertia has to do with space, not the Earth or its surface. Gravity works in the vertical, not the horizontal. The tiny speed changes of an airplane's groundspeed are infitesimal in comparison with the movement of the planet, the galaxy, and everything else. The only time wind bothers us is when we descend through some shear layers (which are rather think and won't make too muich difference to a model) or while taking off or landing.

Dan

I have been reading Dan's Downwind Turn fallacy statement over and over, but I couldn't leave it alone.

I've tried to think as an airplane. And I tried to feel like an airplane, if an airplane could think or feel. But I believe it's how the airplane relates to the ground that matters. In a matter of seconds, my plane was moving very fast over the ground, in a path sort of like a J hook and it crashed.

Would someone please sort it out for me?

Meaning no disrespect, Wan

It might have to do with how fast your turn was, and the power of the engine. If you turn quickly downwind, and the plane has a poor thrust to mass ratio, then it could loose airspeed and drop.

A slow turn downwind would not do the same. Your description of a "J hook" implies a fast turn and stall.

J.

One of the most difficult things to learn as a pilot is that the model flies in the air. The ground has nothing to do with it, or the airspeed at which the model is travelling over the ground. Unfortunately, we humans have trained ourselves to relate everything to the ground. This must be unlearned when flying R/C models.

High speed stalls are usually what brings a model down in a downwind turn. The pilot tightens up on the bank angle and the elevator in an effort to make the model fly over a particular portion of the ground which he/she feels is appropriate. This feeling does not take into consideration the true airspeed of the model relative to the airmass that the model is flying in, hence, the high speed stall.

No matter how long you have been flying, this one can creep up on you and cause mayhem at times.

Ed Cregger

That's just about how it happened. I made a high speed turn away from the high wind, making the plane fly fast over the ground, but not in the wind.

The problems are compounded when I tried to bring the model back by making my sharp "J" bank and throttling back, thereby stalling.

In the future, I will try to practice good flyman ship and unlearn the things that I had conditioned my reflexes to do.

Thanks gentlemen, Wan

No Taipo, I think you may have it wrong. Wind direction or speed has *no* effect on airspeed! For this discussion let's call it TAS (True Airspeed) is the speed at which the aircraft is actually moving through the air mass) Assuming straight and level flight, TAS is a function of power setting. If you're flying at a fixed power setting, no wind, direction has no effect on TAS

*or* GS. If that power setting yields a 30 kt. TAS your TAS remains at 30kts regardless of aircraft directi>

Hi Dan, I sent a response to some of the statements here before reading your reply. You nailed it - sorry I stepped on your reply :) I've tried tom dispel the downwind turn myth for over 50 years but I've never tried your "under the hood" analogy - very good I'll borrow it if you don't mind :-)

Thar ya go: you should have kept the throttle wide open. Like driving: just 'cos you get off the ground..... it doesn't mean you'll survive.

The main thing is the learning: find the cause and avoid it in future.

J.

Yup. Its not like driving a car.

Spend time watching birds flying, and see how they do it.

Hi JH, Why communicate back channel?

True airspeed, Indicated airspeed, Calibrated airspeed. Adding power doesn't always increase airspeed. *First* you drop the nose. Ever heard of the backside of the power curve?

I'd appreciate it if you'd reply via the NG. CYA -

----- Original Message ----- From: "JH" To: "Ed Forsythe" Sent: Saturday, April 22, 2006 1:21 PM Subject: Re: Ailerons ineffective in high wind?

Well , if the bastard looks as though it is sagging in the air: you stick the throttle down and gain some AIRSPEED.

Airspeed is airspeed. No such thing as "true airspeed".

J.

Near the end of my mad dash to bring my plane back, the fleeting thought of me wandering the streets of a new community of homes, looking for my model. I was lucky the crash occured onto the outer wall of a friendly homeowner whose house is on the fringe of the community.

What you have done in such a situation, apply throttle to gain airspeed and risk going further into the housing area?

Just a thought, Wan

Um, turn around and fly away from the housing?

You should always plan ahead -- in a high wind this means going way upwind before you attempt to turn.

San Diego : ) That would be real nice if I could turn around. Remember I said earlier, there was no aileron control?

I liked Tim Wescott's way better. To plan ahead, in a high wind situation, go way upwind before attempting to making a turn.

Anyway, the plane is repaired and ready for good weather.

Good flying, Wan

Half loop, fly inverted back upwind. :)

Half loop up elevator or down elevator? : )

If the model is flying to slow to roll, it will be flying to slow to loop. Add throttle, wait a few seconds and then turn the model around, after the model has acquired some airspeed.

I do not recommend half looping the model because you cannot assess whether the model has sufficient airspeed to complete the maneuver. If it fails, it will fall into a spiral dive, from which there will probably not be sufficient altitude to recover.

Ed Cregger

Ed, I and "San Diego" were talking in jest as you may know. I do appreciate your commentary. Especially the part where I should add throttle. That should work well except I don't have a few seconds left under the situation. However, all is well that ends well, my plane is ready to fly again.

Thanks, Wan

What? Huh? Never mind!

Ed Cregger