Chris Nicastro

My Feedback: (3)

I witnessed this exact situation when my Father was looping a sport plane in high winds one day.
Flying into the wind the plane had a slow ground speed, yes, check. Flying with the wind the plane hauling all the *****, higher ground speed, check.
Then he decided to loop it. Into the wind the plane climbed really fast, always flying with full power this day due to winds, and it quickly reached the top or apex of the loop. On the downside it gained a lot of speed but then with full power and full up elevator it wouldn't pull out of the loop. He stuffed it into the ground. It happened pretty quickly and even rolling out of it with the wind may not have helped in time. I even considered what if reducing power would have helped but you would also think the prop thrust over the elevator should have enough effect.

Once the plane showed its top profile to the heavy winds its pitch authority was basically neutral. It would have needed substantially more altitude to complete the maneuver. The wind increased the radius of the loop.

Another incident I witnessed happened to a guys biplane on a dead stick landing attempt. He was flying in steady fairly high winds and had a the engine quit in the wrong part of the field, downwind. He pointed the plane back into the wind and tried to stretch it out but once the planes forward speed slowed enough it basically stalled and became a kite instead. The wind took it further downwind and it crashed.

As for the boating analogy I disagree. If your trying to make it across the river without a particular destination and your goal is simply to cross then you wouldn't "feel" the river current as you cross perpendicularly, ok.
If you have a destination to land at then you have to adjust for the current and you will feel it. This is the same in flight as in water. When you fly a glider or a powered plane in high winds you work with and against the wind and constantly adjust your flight path. Downwind I have stalled various planes while trying to turn back into the wind using power and rudder, puposely. You can see when the plane is stalling and losing altitude in a more vertical fashion, very mushy controls, very vague feedback, but visually its evident the plane is falling not flying. This requires good stick and rudder coordination and cross control techniques.
If you carry more power thru the turn from tail wind to head wind its normally no problem of course. But! Never present the prevailing wind with the full profile of the plane, maintaining a low bank angle is better, use more rudder.

I've landed, only once, a TF GS Corsair in a tail wind that was so slight it didnt even feel like a breeze to me it was so light. I thought it was negligible at the time. That time I used up all the runway, over 700ft! Wont try that again with any RC plane!

Up here we fly all year pretty much and if your scared of the wind and pick your days then your only flying a few days out of the main season. I call these guys Fair Weather Flyers. I fly mostly scale planes, civilian & warbirds, in all weather even lightly snowing. These types are less forgiving than most so understanding them and their characteristics is crucial to flying them successfully.

So for me its all about understanding the plane you fly and the conditions are what they are.

invertmast

My Feedback: (23)

just goes to show your ignorance, because you obviously didnt take the time to research what i said to determine if its even possible. Plus i have no reason to embellish or lie about something like this to a bunch of "internet" warriors. Experience is experience and when someone with Proffessional knowledge speaks on a subject, its typically best to listen and verify.


A cessna 152 has an vs1 stall speed of 48 knots and a vs0 stall speed of 42knots indicated airspeed, these are at max gross weight and Power off scenarios btw! During the winter time, winds aloft at 8,000+ msl can easily obtain 40+ kts of speed.

On this particular day (very clear skies right after a strong cold front moved through) the winds at 8,000 feet were 65kts. (We were also fairly close to the foothills of the appalachain mountains which tends to product strong winds in the winter in that area as well).

As i was a fairly new CFI at the time and had Never witnessed winds that high at such a low altitude i thought that the winds aloft forecast was wrong, since i had a flight and the lesson plan involved slow flight, stalls and a myriad of other fun things at a "safe" altitude, i figured i'd take the opportunity to see just how accurate that winds aloft forecast was.

At roughly 50-55kts we reached a groundspeed of Zero knots. After manuevering around for abit, i took over the controls and told the student to determine where we were. At this point i had slowed the airplane an additional 15kts. As i did this i watched the gps groundspeed slowly start to count.. 0,1,3,5,10... Etc. if you looked directly down at the ground, you could visually see you were moving backwards. Since gps groundspeed only knows you are moving and doesnt take into account the aircraft heading, it just knew we were moving at 15 knots. Only looking at the ground directly beneath us showed we were actually moving Backwards at 15 knots.


for proof, here is a link to current winds aloft data:

http://www.wunderground.com/Aviation...2.html#a_topad


you can see that if you were in far northern canada currently, you would experience winds aloft anywhere from 15-50kts depending in altitude

in South Carolina when his particular instance happened, it was winter time and the jet stream was dipped deep into the united states. This jetstream was running right over top of SC at the time and was producing some very strong winds aloft.

drac1

My Feedback: (4)

Ignorance and Knowledge?? Hmm.

Well I have spent many a hour in 152's and others over the years and my dad is and has been a CFI for many, many years. I can't recall just how long off the top of my head.

Pretty sure that counts as knowledge and experience, but apparently you know more about ignorance than me, so you win.

cfircav8r

My Feedback: (1)

so does your father also believe that you can stall turning down wind due to the "sudden tail wind"?

invertmast

My Feedback: (23)

Well, you might not be ignorant, but you arent the best at being receptive to others experiences. Your dads experience doesnt count as your knowledge (it would be nice if it was able to be passed down though, wouldnt it!? Lol. I know of some things my dad knows that it'd be nice to know).

Again, most people dont go out searching for what i experienced on that day, it just so happened the circumstances allowed me to experience something out of the ordinary.

drac1

My Feedback: (4)

Well if you read my reply correctly, you would know that I didn't say 'this is what my dad said". I have plenty of flying experience myself.

drac1

My Feedback: (4)

So you can't read and correctly interpret what is written, then insult someone who has nothing at all to do with this thread. You should really let things rattle around a bit more and then wait for the echo to stop before replying.

As they say, there is one in every crowd.

And guess what? You're the one in this crowd.

RZielin

My Feedback: (1)

There is indeed acceleration required to produce a change in heading within the moving air mass. So yes there must be some force applied to accelerate the plane around turns. Gliders use the force of gravity, trading a bit of altitude in return for the turn. Powered planed can do that OR apply force with the engine. The thing is, the force and acceleration required to turn the plane is exactly the same whether you're turning upwind, downwind or crosswind.

This assumes you're making the turns with the same control inputs. The turns will all be identical in relation to the airmass and in airspeed lost, and force required is always the same for every turn. Now if you try to make the turns have the same GROUND TRACK, and therefore look the same to the ground based RC pilot, you will then require more force to make the downwind turn. The downwind turn must be much quicker than the upwind turn, more bank angle, more elevator in order to maintain the same ground track radius, thus more acceleration and thus more force required.

So the point is to make/allow the downwind turn LOOK different from the ground than the upwind turn LOOKS. You do this by making the control inputs the SAME. No more force (throttle) needed when downwind than upwind. The turns look different from the ground but if control inputs are identical, the plane turns the same in terms of airspeed lost and you won't stall downwind any more than you would upwind.

RZielin

My Feedback: (1)

There's another explanation for what you witnessed: both pilots stuffed the planes, not the wind. They didn't understand the point of this whole thread. The problem was that they tried to make the ground track and visual appearance of the maneuvers LOOK the way it looks in calm air. In wind, a perfectly circular loop in relation to the airmass looks egg shaped to the ground based pilot. Once the plane loops over the top, its going downwind and down the field fast. Your Dad tried to maintain a circular loop from his perspective, rather than having the patience to let the plane move way downfield in a long lazy ellipse (as seen from the ground) as it made its normal circular loop in relation to the moving air mass. He jammed more up elevator to tighten the loop, at the very apex where airspeed is the lowest. Result, he stalled it. Even if he maintained airspeed over the top by applying throttle, he could easily cause a high speed stall by applying enough elevator to stall the wing. The other incident is the same situation. Not enough patience to let the plane fly itself, fear of not making the runway, so he pulled up too hard and stalled.

In both cases, pilot error caused by a visual perspective problem, not visualizing the moving air mass with the plane in it. NOT a result of the wind robbing airspeed during a maneuver.

drac1

My Feedback: (4)

Are you saying that a round loop that actually looks round can not be done when it's windy?

RZielin

My Feedback: (1)

Sure a loop can still look round in wind. Thats what pattern competition is all about and the pattern judges look for the roundness of the loop regardless of wind conditions. But that's what makes it so difficult (and risky) to fly pattern properly in the wind. There's no hope of doing it safely if you're not conscious of the fact that a circular appearing loop is a different maneuver in the wind. In wind, you'd actually have to fly some sort of weird egg shaped ellipse, with the long narrow end of the egg facing into the wind and up at some angle, I think. Imagine drawing a perfect circle on a piece of paper as you pull the paper sideways at a constant (or not so constant speed). Worse yet, if while you're doing that, the pen ever stops on the paper and just moves too slowly across the paper it "crashes", that's what you're dealing with. That's what you're doing with the airplane, drawing a perfect circle in the sky over your arbitrary piece of ground reference, while the plane's canvas (the air mass) is moving on you. If you can't draw that circle on moving paper, AND keep the pen moving against the paper within a limited range of pen speed, what makes you think you can safely fly an airplane in wind and make the circle perfect?

Most of us can fly a loop safely in dead calm. I'm saying that anyone can fly a loop just as safely in big wind, as long as they let it look like an egg and don't force it to look round when you're not expert enough for that. You have to do it while being aware of the moving air mass. You have to visualize airspeed rather than ground speed, and you have to know the limits of how much control input you can apply without stalling. And you have to judge that NOT by the ground track that the plane is flying or it's appearance in the sky, but by the airspeed you're estimating.

Trying to make a turn or a loop in wind LOOK the same as a turn or loop in dead calm is a fundamentally different maneuver. Not being aware of the differences is why people stall on the downwind turn. They're trying to draw the same curves on the moving medium that they always made on stationary medium, but they're not conscious of the movement of the medium, and the fact that this requires a different curve to be drawn.

I hope that makes sense, but I doubt it.

drac1

My Feedback: (4)

You are on the right track, but have taken a slight detour.

A round loop will look round regardless of the wind and it's not "risky" to fly pattern in the wind. The cut off for competition is 12 m/s which is 43.2 KMH or 26.8 MPH.

If you are flying some sort of weird egg shaped ellipse with a long narrow end, then that's exactly how it will look. Flying pattern, the loop is performed in reference to the centre pole and must be central to that reference, regardless of how windy it is to score well. Just because the wind is blowing from say left to right, doesn't mean the loop will move left to right with the wind. The loop will stay central to the fixed point, which in this case is the centre pole. What does change is the attitude of the plane, but the flight path is still round. The CG of the plane must describe a round flight path, not the thrust line.

If it is windy and the plane is wind corrected, then the loop may appear to be not round, but the CG of the plane will follow the round loop. This is where experience in flying and judging pattern comes into play.

As per the FAI Sporting Code, Section 4, Annex 5B.8.4, "A loop must have by definition, a constant radius, and be performed in the vertical plane throughout".

This applies regardless of the wind. Trying to maintain constant speed, (which is another judging criteria), makes it harder again when it's windy.

I've been flying and judging pattern for 17 years and currently fly F3A class. Flying correct geometry in the wind isn't easy.

BobbyMcGee

Now, look here guys ... This whole topic is BACKWARDS ...

Or shall I write, S D R A W K C A B

The real myth is the UPWIND TURN

So, everyone please re-group and let's get a new start on the MYTHS OF THE UPWIND TURN

Maybe even better ... start a new topic on it, and lay this one to rest.

BobbyMcGee

Of course there is always the obvious answer to everyone's concern here ... Just make sure the next plane you buy is equipped with the "automatic upwind correction feature" which is often called the "automatic downwind correction feature" by novices. It also goes by the term, "Anti-downwind correction feature" or "Anti-upwind correction feature." If you really want to impress the aircraft dealer, simply reference it as; ADC or AUC, and insist that this valuable feature is installed in your aircraft.

sensei

OK lets see here you stated:

I have never had a stall in a downwind turn so obviously I do not need extra practice. However, I attribute this to knowledge not practice. To think, we can all get just a little knowledge from a book and become an ace pilot too.

I know to not try to slow down a plane because it is traveling downwind. Gee, now that's a novel idea, why didn't we all think of that. Now that I think about it I was always told if you pulled back really hard on the stick while going down wind you could stop the airplane in mid flight while holding altitude.

I know to keep the elevator at the same approximate position and let the plane find its airspeed. Oh really, fly something with a 65 + oz. wing loading and not much wing area like some of the R/C war birds out there and let that bad boy find it's own airspeed on a down wind turn while low, slow and power off and see how that works out for you, in fact please get some video so we may all benefit from your loss, and wisdom as well. You just can't compare flight characteristics of something like your Sig Kadet with a really light loading to the wide open envelope of everything else out there.

I do not judge the airspeed based on ground speed. While I am flying my R/C airplanes I don't judge airspeed, ground speed, airspeed based on ground speed, or any variation of them. I have found that it is just better to leave all the BS back at the keyboard and just shut up and fly, burn gas, burn fuel, burn milliamps or any variation of these while yes I am going to say it, practicing maneuvers while flying. Oh and by the way, I have found allowing yourself to breath while flying or practicing is so much more gratifying and, and, just way more satisfying while your toy airplane is in the air...

Based on what I have read so far you may have never actually planted one yet, but then again from your post count since 2002 I would wager you spend may way more time on the keyboard and type a far better tale of flying than you can actually fly. Just my opinion though... Anyways do have yourself a nice day there Sport.

Bob

PacificNWSkyPilot

My Feedback: (19)

Your first sentence detailing what you thought was the case, well, that was incorrect, so the rest of your post, which is based on that, is irrelevant.

Jim

PacificNWSkyPilot

My Feedback: (19)

Well, it seems the wind is getting hotter and the posts are getting longer, and nothing worth listening to is being said here any more.

It's been real, guys.

Unsubscribed.

Jim

dirtybird

My Feedback: (5)

This has been a very interesting thread.
It has been interesting to learn different ideas even some of the weird ones.
As my final post I would like you to consider the following.
Consider a full-scale making it 180° turn with no wind.
The pilot will tilt the wings in the direction he wants to turn. He will then increase the elevator angle to increase the angle of attack of the wings to compensate for the loss of lift due to the angle of the wing and provide the force required to overcome the force generated by the change in the direction of the momentum. He will also add rudder to assist with the change direction and correct angle of the aircraft nose.
If there is a wind he will just slightly increase the elevator angle to overcome the difference.


If a model flyer decides to change the direction his model is flying and there is no wind he will likely tilt his wings to vertical and pull the airplane around with the elevator. He will not bother with the rudder. He will end up with his wings vertical having used all his wing lift to counteract the change in momentum. He will end up with no momentum and zero airspeed. He will have to rapidly level his wings and add power or he will lose altitude.
If you add wind in any direction just make this situation worse..

Jaybird

Hmmm...some BIG grains of salt needed here.....

Jaybird

chip_MG

My Feedback: (14)

Here is the issue. There is a misunderstanding between model airplane "RC pilots" VS "Real airplane pilots". A model airplane can sustain flight at a much lower speed due to its weight being much less than any full scale aircraft. A model can be a lot lighter and therefore can fly at a much slower speed. A model can stall at say 5 MPH and maintain level flight at say 7 MPH. We fly models all the time at 10 -20 mph of wind speed. That I think is where the confusion is coming from because a full scale airplane cant fly as slow. A full scale J3 cub has a stall speed of around 40 MPH so there ya go.

Jaybird

A wing will stall when the critical angle of attack is exceeded. The size of the plane (full size or model), airfoil shape and the air conditions affect what speed and attitude that will occur.

Jaybird

chip_MG

My Feedback: (14)

Jaybird Sounds like you must be a full scale pilot and fully believe in the "bernoulli effect" for lift. The other error of full scale pilots
[h=2][/h]

Lownverted

My Feedback: (4)

This makes zero sense.

I'm still completely mystified as to why folks choose to believe there is a "downwind turn" problem when it can be proven over and over again that it doesn't exist. Once you leave the ground THE AIRCRAFT DOESN'T KNOW, OR CARE ABOUT ANY WIND. Its simply a perception issue with you being stationary on the ground, controlling a vehicle flying within a moving air mass, and its speed relative to you.

Seriously, do you think all of the aerodynamic academia have it wrong, but you with your R/C plane know something everyone else missed? I think not, and its the height of arrogance to think so.

Interestingly enough there is a documented effect about people like this. Its called the Dunning-Kruger effect. In short, unskilled people tend to over estimate their abilities and knowledge, while those skilled people tend to under estimate theirs. I see many examples of that in this thread lol

https://en.wikipedia.org/wiki/Dunnin...3Kruger_effect

Jaybird

Yes, I am a full scale pilot, but I also know a flat plate wing (no airfoil so no Bernouili effect to "suck" a wing up into the air) like on an indoor foamy or other type model will still fly...with the right angle of attack. There are many forces at play to keep wing in flight. To ignore any of them can get you into trouble. Again...grain of salt.

Jaybird

Jaybird

With onboard telemetry available now on models for airspeed and altitude I would think it would be possible to get numbers that would show what is going on with the model rather than having to interpret from a distance on the ground.

Jaybird