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#21
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Robert Moore wrote: Yep! We fought this battle for about two weeks last year. There were two groups, one was the slow down and use flaps with a shallow angle of bank and the other group (me) quoting the aerodynamic textbook solution of flying at maneuver speed and using about 75 degrees angle-of-bank. Well, I'm almost certainly going to be at max angle of climb by the time I decide I need to turn around, so maneuvering speed is out of the question. I'll be starting my turn with 24 degrees of flaps at 70 mph. George Patterson Battle, n; A method of untying with the teeth a political knot that would not yield to the tongue. |
#22
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Before you try this you should know that the load rating for your 172 with
the flaps down is 2.0G and the load factor in a level 60deg turn is 2.0g. Mike MU-2 "Casey Wilson" wrote in message ... "Brian Burger" wrote in message ia.tc.ca... On Thu, 11 Mar 2004, Casey Wilson wrote: My apologies for coming in late, if this has already been mentioned. How about a chandelle or wing-over? http://www.skyjackmotorsports.com/IAC24/aresti.html Cool Aresti diagrams, but... if you're really, honestly in need of a canyon turn, you're unlikely to have the excess airspeed you need to pull a wingover or chandelle off, and if you're turning away from rising terrain you might not have the altitude needed to trade for the needed airspeed either... Sparky Imeson's "Mountain Flying Bible" points this out at least three times; he's in favour of the 60-degree bank, with flaps up to full as appropriate, and power as needed. Personally, doing these turns in a 172N starting at ~80 KIAS, I've gotten the plane turned around inside the long dimension of a high school running track that was below us - that's about 200-250ft, give or take. Thanks for the book tip, Brian. First, about the mountain flying. All my experience has been in the Southern Sierra Madre, south of Mt. Whitney, generally, although I've poked the nose over a few other ranges and ridgelines. Maybe I'm too conservative, but I don't fly "up" a canyon blind. I have to pretty much know what's up there before I let the ridgelines get above the wings. Same thing going down-canyon -- I've got to know where it opens up. As far as the chandelle and wing-over, I was looking for opinions. Now you piqued my interest in horsing the club's 172S into a 60-degree-bank turn with full-flaps. I don't remember doing that with flaps. I've got a date with my CFII next week. I wonder if the club has parachutes.... Just to pick a nit... the straight sections of the high school track (presuming it is around a football field) is closer to 400 feet. Still a darn tight turn, though. |
#24
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In article k.net,
"Mike Rapoport" wrote: Before you try this you should know that the load rating for your 172 with the flaps down is 2.0G and the load factor in a level 60deg turn is 2.0g. I do believe the load limit is 3G with the flaps down. -- Dale L. Falk There is nothing - absolutely nothing - half so much worth doing as simply messing around with airplanes. http://home.gci.net/~sncdfalk/flying.html |
#25
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Ary your sure? From memory, the requrement is 2.0G (from a Barry Schieff
book). In my flight manual (not a 172) the limit is listed as 2.0G. Mike MU-2 "Dale" wrote in message ... In article k.net, "Mike Rapoport" wrote: Before you try this you should know that the load rating for your 172 with the flaps down is 2.0G and the load factor in a level 60deg turn is 2.0g. I do believe the load limit is 3G with the flaps down. -- Dale L. Falk There is nothing - absolutely nothing - half so much worth doing as simply messing around with airplanes. http://home.gci.net/~sncdfalk/flying.html |
#26
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In article k.net,
"Mike Rapoport" wrote: Ary your sure? From memory, the requrement is 2.0G (from a Barry Schieff book). In my flight manual (not a 172) the limit is listed as 2.0G. Mike MU-2 Yeah, my info manual for the 172P shows 3g with flaps down..pretty sure it's the same for the 172S -- Dale L. Falk There is nothing - absolutely nothing - half so much worth doing as simply messing around with airplanes. http://home.gci.net/~sncdfalk/flying.html |
#27
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When you NEED a canyon turn, you usually are already at slow airspeed,
due to the fact that you have been trying to climb (and can't outclimb the terrain, so you want to turn around). I teach using best angle of climb (Vx), go over to one side of the canyon, and make only as steep a turn as necessary to turn before you come to the other side of the canyon. Use of flaps, in my opinion, unecesarily complicates things. But it can be done with or without flaps. Like Mike R pointed out, max wing loading goes down with the flaps down, and mountains do have turbulence, so lots of turbulence would suggest not using flaps. You can practice this by doing the turns "above" the canyon, and when you get proficient, drop down "into" the canyon. Use the steepest bank angle you dare. It is suprising how small a canyon you can be in, and still be able to turn around. You may want to get some instruction in "steep turn stalls". If you want true, scary, thrilling and dangerous mountain flying, the wilderness airstrips in Idaho await you. There are primitive airports in the bottom of some BIG canyons and you can pretty much forget about staying over an emergency putdown area, they don't exist. Don't try it on a hot summer afternoon, morning and after 6 pm are best. Get some local instruction, and you will be flying patterns down in the bottom of 4000' deep canyons landing on bumpy, short grass fields. Yikes! Takeoffs are just as exciting. |
#28
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OK I guess that the requirment is a *minimium* of 2.0G and some airplanes
are higher. Mike MU-2 "Dale" wrote in message ... In article k.net, "Mike Rapoport" wrote: Ary your sure? From memory, the requrement is 2.0G (from a Barry Schieff book). In my flight manual (not a 172) the limit is listed as 2.0G. Mike MU-2 Yeah, my info manual for the 172P shows 3g with flaps down..pretty sure it's the same for the 172S -- Dale L. Falk There is nothing - absolutely nothing - half so much worth doing as simply messing around with airplanes. http://home.gci.net/~sncdfalk/flying.html |
#29
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"Mike Rapoport" wrote in message hlink.net... Before you try this you should know that the load rating for your 172 with the flaps down is 2.0G and the load factor in a level 60deg turn is 2.0g. What's a "level 60 degree turn"? |
#30
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This is based on my experience flying a small, single engine, GA plane
around Colorado and Idaho. From my experience, you usually wont be at manuevering speed for a canyon turnaround, because you are trying to climb. You can't climb fast enough to outclimb the terrain. You are trying climb out somewhere around Vx to Vy. I suppose it all depends on what you are doing. The times when I have NEEDED a small radius turn I was in a narrow canyon, flying a pattern to an unimproved strip. In another case, I went up a canyon that ended at a mountain, not at the airport. (I went up a dead end canyon, mistakingly thinking there was an airport there.) It was hot, bumpy, I was heavy, and I was slow. I suppose if you are flying high speed manuevers in canyons and want to turn around, then turning at Va might be an option. But that is not how most of us fly in the mountains. Most of us are either climbing out of an airport, and can't outclimb the terrain, or are headed up a canyon, it's not working out due to steep terrain and downdrafts, so we have to turn around. We are flying at speeds closer to Vy and Vx, not at Va. If I could get Va, I'd pull up until at Vx and might not need to turn around. Most small planes will barely climb at Va. My Husky has a Va of 94. At gross weight on a hot day, I would not be climbing much at that speed, maybe 50-100 fpm. And a Husky climbs well (but not at Va it doesn't). The Cessnas I have flown are similar (though most don't climb as well as my Husky). If you are talking about flying fighter jets in the mountains, zooming around the canyons, you have LOTS of power, then I would suspect it is different. Get enough power, your climb problems are over, just go straight up! Robert Moore wrote in message .7... "Marc Lattoni" wrote Today we did canyon turns, not at 30, not at 45 but more than 45 degrees. Sort of standing the airplane on its wingtip as we turn. Yep! We fought this battle for about two weeks last year. There were two groups, one was the slow down and use flaps with a shallow angle of bank and the other group (me) quoting the aerodynamic textbook solution of flying at maneuver speed and using about 75 degrees angle-of-bank. Quoting from "Aerodynamics For Naval Aviators": "The aerodynamic limit of turn radius requires that increased velocity be utilized to produce increasing load factors and greater angles of bank" "The maneuver speed is the minimum speed necessary to develop aerodynamically the limit load factor and it produces the minimum turn radius within aerodynamic and structural limits." Bob Moore |
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