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Old Aug 27, 2012, 10:23 AM
Space power
cfircav8r's Avatar
United States, IA, Hampton
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Most flight instructors teach adding power to turns, in the pattern, because they feel it is safer for a new pilot and yea so what if it is not necessary it doesn't hurt anything. Let me give you a real life scenario to show you a lack of understanding does matter occasionally. A pilot is flying in the mountains at the airplanes service ceiling. He has full throttle just to maintain altitude, he mistakenly heads up a box canyon and can't climb over it. He is on the verge of stall and hugging the upwind side of the canyon. When he decides to turn around he is concerned about stalling in the turn so turns into the wind to get some extra lift. Well guess what there was no extra lift because it doesn't work that way, and this gives him very little room to turn and stalls in an attempt to tighten the turn, spinning into the trees. Had he turned with the wind he would not have lost any lift and would not have been inclined to tighten the turn allowing him to maintain flying speed and getting out of a bad situation. I am a flight instructor since 1996 (CFIrcav8r, get it?) and can get several more to give you the same information. Just curious did you go to a part 141 school or part 91?
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Old Aug 27, 2012, 02:36 PM
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It was 91, Beech Aero Center. And by previous duty Navy and Air Force pilots. I forgot the box canyon example.
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Old Aug 27, 2012, 02:42 PM
An itch?. Scratch build.
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Quote:
Originally Posted by cfircav8r View Post
Chop I have on countless occasions flown a C-150 with the stall horn chirping on the edge of stall flying backwards, and was still able to turn 180 degrees without adding power or losing altitude and never once stalled. How do you explain that?
C-150 stall speed is 40 knots ?, so you were flying into a 40+ knot wind and watching the ground to check your ground speed and realized it was moving forwards, (you were therefore travelling backwards relative to the ground).
You turned gently trying to keep the wings level to maximize lift, (a banked turn would have lost lift).

And by luck, you survived . I wonder what an instructor would have said if they had been sitting along side you during training
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Old Aug 27, 2012, 03:54 PM
Space power
cfircav8r's Avatar
United States, IA, Hampton
Joined May 2012
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GPS is a wonderful thing, lets you keep your head in, and at 3500' you have plenty of time to react, especially in a 150. At near stall speeds you can do a standard rate turn with 5 degrees bank. A very safe manuever when done properly, and you only get those winds at altitude on normal days.
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Old Aug 27, 2012, 05:33 PM
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Toowoomba, QLD, AUSTRALIA
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Quote:
Originally Posted by cfircav8r View Post
A pilot is flying in the mountains at the airplanes service ceiling. He has full throttle just to maintain altitude, he mistakenly heads up a box canyon and can't climb over it. He is on the verge of stall and hugging the upwind side of the canyon. When he decides to turn around he is concerned about stalling in the turn so turns into the wind to get some extra lift. Well guess what there was no extra lift because it doesn't work that way, and this gives him very little room to turn and stalls in an attempt to tighten the turn, spinning into the trees.
I might be missing something here so if I'm wrong (and I probably will be from the sound of it) please tell me, but I'd fully expect the upwind side of a canyon to be the worst place to be flying. Do you get some weird rotor turbulance that puts the upwind side in a calm spot and/or upward part of the rotor?

This might be one of those new things I learn every day

EDIT: Ahhh, the "upwind side" is actually the side that is downwind, now I get it.......
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Old Aug 27, 2012, 06:06 PM
Space power
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United States, IA, Hampton
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Depends greatly on how close, how far beneath the crest, how steep the slope and the amount of wind, but yes it is not the best place to be and that scenario points out several additional mistakes that were made. It was the last one that broke the camels back, and had he turned the other direction it may have ended better.
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Old Aug 27, 2012, 11:35 PM
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@ cfircav8r,

Yep, I just enjoyed a couple of minutes googling up "canyon flying".

I remember my Dad telling me a story about a time when a bunch of his mates hired a Cessna 182, middle of summer and stinking hot, overloaded to boot and out in the middle of nowhere. They needed all the runway plus a bit more to get off and when a mountain range (just a few hills really) appeared far away on the horizon, a quick double check on the map and it was decided that under the circumstances the time to start climbing was right now.....

The biggest hill between Julia Creek and Ayr is only about 2600ft
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Old Aug 30, 2012, 07:15 AM
Thailand
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Just go and practice and fly in any wind.
I lived in England before and if you waited for a calm day you waited for ever so fly in any wind and you get so you don't notice whether it's into wind or not.
Jim
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Old Aug 30, 2012, 09:14 AM
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Nice jet here. Now what happens if the head wind suddenly drops ?

Watch this 230-ton Airbus A330 Stopping In Midair for a Few Seconds (1 min 28 sec)
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Old Aug 30, 2012, 09:20 AM
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Another interesting airbus video, that's what. Unless he has enough power to accelerate pretty quick...
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Old Aug 30, 2012, 09:39 AM
An itch?. Scratch build.
eflightray's Avatar
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Originally Posted by Chophop View Post
Nice jet here. Now what happens if the head wind suddenly drops ?
Probably absolutely nothing noticeable from the ground. The plane will continue to fly. The on-board computer and/or the pilot may raise the throttles a little sooner than in the video. But only if it was flying in a very very strong head wind. (i.e. a very large difference in wind speed).

What do you think the airspeed was during the videos titles reference to 'Stopping in Midair....' ?

What do you thing the airspeed was just before touch down ?.
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Old Aug 30, 2012, 02:07 PM
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Eflightray, more extreme example to illustrate the point.

Plane is flying at an airspeed of 30mph into a 30mph headwind and has a stall speed in that config (power/aoa,flaps etc) of 25mph.

The wind suddenly stops, assume a nice clean step-function.

What happens to the plane? It will quite literally fall out of the sky, and do so until it can accelerate to a high enough airspeed it can generate sufficient lift.
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Old Aug 30, 2012, 04:38 PM
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Exactly, now as I had been arguing, the turn to downwind at or better yet, below MCA (minimum controllable airspeed) can do the same. But only if the plane's inertia is great enough to delay the resultant speed up. I say can happen but not will happen. It is a grey zone thing.
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Old Aug 30, 2012, 05:19 PM
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Originally Posted by Chophop View Post
Exactly, now as I had been arguing, the turn to downwind at or better yet, below MCA (minimum controllable airspeed) can do the same. But only if the plane's inertia is great enough to delay the resultant speed up. I say can happen but not will happen. It is a grey zone thing.
If the wind is steady, no, the situation is different than the wind suddenly changing.
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Old Aug 30, 2012, 05:35 PM
Space power
cfircav8r's Avatar
United States, IA, Hampton
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Quote:
Originally Posted by Chophop View Post
Exactly, now as I had been arguing, the turn to downwind at or better yet, below MCA (minimum controllable airspeed) can do the same. But only if the plane's inertia is great enough to delay the resultant speed up. I say can happen but not will happen. It is a grey zone thing.
Minimum controllable airspeed (Vmc) is only for multi engined aircraft. That is the slowest safe speed when the critical engine fails. Vs, or stall speed, is what you are thinking of. Yes slightly above that speed any gust or sudden change in wind direction can cause a stall, however changing the direction of the aircraft will not induce a stall if the pilot does not increase the AOA beyond the critical AOA.
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