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Old Jul 03, 2012, 10:07 PM
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The C150 was lots of fun going backwards. Stall horn was annoying. As you said a gentle touch was needed. I flew out of St Andrews, practice area was just East of Selkirk.
Carl
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Old Jul 04, 2012, 12:46 AM
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Quote:
Originally Posted by CARL SCHIMNOWSKI View Post
The C150 was lots of fun going backwards. Stall horn was annoying. As you said a gentle touch was needed. I flew out of St Andrews, practice area was just East of Selkirk.
Carl
When did you do this? Cadets? Me in 1986 out of Gimli. Small world eh!
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Old Jul 04, 2012, 04:45 AM
An itch?. Scratch build.
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the down wind turn -

Forget the wind speed. Whether calm or 20mph. Think stall speed.

If you slow your plane down to its stall speed it stands a good chance of stalling. Whether it is flying in the calm or in a gale.

As has been said in many posts, don't throttle back too much on the downwind flight. Don't relate your planes flying speed to ground speed.

Turbulence, wind shear, gusting etc, can happen at any time. Down wind, across wind, and into wind. Don't confuse those with slowing the plane down yourself to near its stall speed and then turning. Turning creates more drag, more drag reduces speed. Crunch!.

Looks like we are running out of excuses for crashing other than blaming ourselves

But then there is always, "Did you see the air shimmer just before the she went down ?. Darn it!, ....I reckon there's a cloaked Klingon Warbird over the field. ....shot my plane down."
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Old Jul 07, 2012, 01:36 PM
Tossing planes into the snow
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Usually when you see a shimmer, that means their cloak is failing, and they need to replace their dilithium crystal. Most of the time you don't see anything at all, and end up blaming it on radio failure.
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Old Jul 09, 2012, 12:21 AM
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I wonder about the sail effect on a plane turning around from a tail wind as it banks and the wings face the wind. There's going to be an extra speed vector there.

The wind woul push it further downwind, regardless of the flight speed and that added negative momentum would be carried as the plane completes the turn.
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Old Jul 09, 2012, 12:39 PM
An itch?. Scratch build.
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Originally Posted by AleG View Post
I wonder about the sail effect on a plane turning around from a tail wind as it banks and the wings face the wind. There's going to be an extra speed vector there.

The wind woul push it further downwind, regardless of the flight speed and that added negative momentum would be carried as the plane completes the turn.
A plane doesn't know it's flying in a wind, it's just flying in a block of air that happens to be moving relative to the ground. You have to stop thinking of standing still and watching a plane in a wind.

Sail boats etc, are still linked to the ground, (well the water), in fact they would probably be completely useless if they lost contact with the water, ('flew' for a while) .

As already posted, free flight models do not have this problem, it's only when a model is being flown by someone who is ground based, (i.e. using RC), that the 'phenomena' is believed to happen.

When flying in air turbulence, any thing can happen, which ever direction you fly relative to wind direction.
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Old Jul 10, 2012, 12:47 PM
Tossing planes into the snow
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Originally Posted by eflightray View Post
You have to stop thinking of standing still and watching a plane in a wind.
I think that is the key right there. We have to stop thinking that way, even though we actually are standing still watching a plane in the wind. From our stationary viewpoint, we are presented with the illusion that it slows down as it goes upwind and speeds up when going downwind. It's more than just an illusion. It really is slowing down and speeding up, but only if referenced from a stationary position.

If you were sitting in the plane, doing circles on a windy day, you wouldn't feel that speeding up and slowing down at all. It would just feel like you were doing circles on a calm day.
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Old Jul 12, 2012, 08:11 PM
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The downwind turn problems seems to be pilot induced. I have never seen free flight models having problems cirkling in wind.
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Old Jul 13, 2012, 12:02 AM
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The downwind turn problems seems to be pilot induced. I have never seen free flight models having problems cirkling in wind.
You've never seen mine then. When the wind picks up, they stop circling, turn downwind and fly away. Why they never fly straight into the wind is beyond me.
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Old Jul 14, 2012, 11:24 AM
Tossing planes into the snow
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Bringing free flight models into this discussion is an interesting idea. If the downwind turn is all about the pilot misjudging airspeed, then the idea of observing an uncontrolled model is meaningful. It is especially interesting to me right now because I just got a new electric sailplane, and with a little tinkering, it is trimmed so well it flies by itself. I am getting a kick out of seeing just how long I can go before touching the controls.

If I trim it to go straight, it is less predictable but tends to face into the wind a little more than away from it. If I put on some rudder trim, it will do nice circles as it eventually moves downwind. I can't think of a reason why a FF plane would have any preference about pointing into the wind or away from it.
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Old Jul 14, 2012, 02:20 PM
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There's some good youtube vids on Einstein's relativity and frames of reference. That's exactly what goes on with the wind. The air mass the plane is flying in is one frame, the ground is another.
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Old Jul 15, 2012, 06:22 PM
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Originally Posted by Jovanx View Post
I can't think of a reason why a FF plane would have any preference about pointing into the wind or away from it.
I can, because a well designed and trimmed FF glider will react to turbulance to hopefully turn away from sink and turn into lift. The turbulance that you get when the wind picks up a bit can/will confuse it. FF planes are built crooked and bent with funny warps for this reason.
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Old Jul 16, 2012, 06:20 PM
Tossing planes into the snow
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Originally Posted by bjr_93tz View Post
I can, because a well designed and trimmed FF glider will react to turbulance to hopefully turn away from sink and turn into lift. The turbulance that you get when the wind picks up a bit can/will confuse it. FF planes are built crooked and bent with funny warps for this reason.
That is a very interesting idea, not only from the perspective of this forum, but also relating to riding thermals. This idea is new to me and I would like to know more. What do you make crooked in order for the glider to turn into thermals?
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Old Jul 17, 2012, 05:02 PM
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Probably best to spend some time with free flight people to answer that, but even then it's a case of certain things work for certain types of machines.

I know I've used out of balance wings, offset and/or different size wings, plenty of WASH-IN to promote tip stalling, tilted stabs, bendy fuses which flex differently under power and under glide and I'm not even hard core.
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Old Jul 18, 2012, 01:24 PM
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United States, KS, Overland Park
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let me throw my .02 on what my limited hobby time has noticed. In high winds they are usually very gusty. gusts to the nose or tail are expected and uneventful. Now lets look at the downwind leg. halfway through your downwind turn you have the wind and associated gusts coming at 90 degrees. Now how are your wings banked? that wind is essentially hitting a downward angled spoiler. It will cause the plane to drop, the solution is to pull up quickly for a lot of people. If you are cruising slow, you could induce a stall and you will be scrubbing airspeed. alternatly on the upwind turn the wings are angled upwards to the wind. it will cause the plane to lift, you counter by pointing the nose down and gain airspeed. you have to keep in mind in small scale like this a 5-10 mph wind gust is going to affect the plane when its hitting it in the side. especially if the wings are banked.

That's my theory and I'm sticking to it.
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