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#11
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spins from coordinated flight
I think you got me here, I cannot gin up a reference frame alibi. Let me
try this: The airplane turns due to the horizontal component of lift. If the horizontal component of lift is exactly equal and opposite the apparent centrifugal force (a coordinated turn) can the airplane depart? Regards Todd "Jose" wrote in message . net... Can a certificated airplane depart if the ball is precisely in the middle[?] If the airplane is changing heading, then it is yawing, irrespective of the ball's position. Jose -- You can choose whom to befriend, but you cannot choose whom to love. for Email, make the obvious change in the address. |
#12
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spins from coordinated flight
Todd W. Deckard wrote:
"Dudley Henriques" wrote in message ... There is only one thing you have to know about spins. To enter one you need 2 things to be present; stall and a yaw rate. So to corner your answer to my question: you cannot? spin from coordinated flight. The airplane must be yawed during the stall break (thus the inclinometer ball slips or skids to one side). My question is not to seek out practical advice in spins, or recoveries. It is to explore two academic debates: Can a certificated airplane depart if the ball is precisely in the middle and is there something telling in the emphasis from the foreign sources cited that exposes a gap in our US training practices and material. Thank you for your response. I'll be making a new years resolution to try it out in the neighboorhood Decathalon (with an appropriate chaperone) but as it is cold and snowy I thought I would put it to the uunet. Best regards, Todd You are correct; IF coordinated flight is being defined as ball centered. This is indeed what is taught to most new students as they begin flight training.....that is until they start doing slips :-)) When and if you get into aerobatics or begin flying with advanced instructors with deep aerobatic backgrounds you learn quickly that coordinated flight can mean cross controlled flight as well as the usual definition with everything going ball centered in the same direction :-) I once flew a Pitts Special the full length of a major airfield holding it in knife edge flight. In the TRUE sense of coordinated, holding the aircraft in knife edge would be considered as coordinated flight. Depending on the instructor, you either learn that coordinated flight is with the ball always in the center, or you can be taught that you are coordinated when the control pressures are applied in the exact amount necessary to place the airplane in the sky at the exact configuration required at any instant in time. I prefer the latter definition and have taught my students this way for many years. -- Dudley Henriques |
#13
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spins from coordinated flight
Thanks for this, this is consistent with what I believe (however I would be
eager to be rebutted). Todd "Dudley Henriques" wrote in message The answer to the ball question is no. It won't spin. A ball centered airplane in a climbing turn is compensated by rudder and is considered coordinated (in the classic sense). If you introduce a climbing turn stall with the ball centered, you might get a temporary wing drop at the break but unless you introduce a yaw rate as the stall breaks; no yaw rate...no spin! -- Dudley Henriques |
#14
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spins from coordinated flight
Todd W. Deckard wrote:
I think you got me here, I cannot gin up a reference frame alibi. Let me try this: The airplane turns due to the horizontal component of lift. If the horizontal component of lift is exactly equal and opposite the apparent centrifugal force (a coordinated turn) can the airplane depart? Regards Todd "Jose" wrote in message . net... Can a certificated airplane depart if the ball is precisely in the middle[?] If the airplane is changing heading, then it is yawing, irrespective of the ball's position. Jose -- You can choose whom to befriend, but you cannot choose whom to love. for Email, make the obvious change in the address. It can if you introduce an accelerated stall and a yaw rate from this turn. -- Dudley Henriques |
#15
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spins from coordinated flight
"Kyle Boatright" wrote in message My thought is that we're splitting hairs in this thread. If the airplane is in coordinated flight and stalls straight ahead (no wing drop), a spin can't happen. But on most aircraft, one wing will drop first even if the ball is centered. This wing drop creates a yaw, opening up the possibility for a spin. But the links that Dan_Thomas sent me indicated that the airplane would not stall "straight ahead" if you were in a climbing turn. The outside wing has a higher AoA which diverges even further as it initially drops. It was intriging to me as our vacation strip demands a short field takeoff into a hedgerow of trees and you'd want to be mindful of this if you stumbled into a maximum performance evasive manuever thru errors in planning or execution. |
#16
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spins from coordinated flight
Kyle Boatright wrote:
"Dudley Henriques" wrote in message ... Todd W. Deckard wrote: I have a limited exposure to spins (I've demonstrated spins or received spin instruction in 5 different airplanes on six different occasions). I have a commercial certificate (although you wouldn't think so from my demonstration of a chandelle). Maybe I did have to demonstrate a power on stall while in a climbing 20 degree bank, once. As I recall, we survived it. I return to the original question: if the ball is in the middle will it spin? Becuase I believe snowmobile suits are for snowmobiling and not for flying I won't have a chance to explore it with an aerobatic instructor and an appropriate (but drafty) airplane for a few months -- so I thought I would put the question in a bottle and throw it in the ocean. Regards Todd "Bertie the Bunyip" wrote in message ... On Dec 27, 1:42 pm, "Todd W. Deckard" wrote: Can you depart and spin from coordinated flight? Specifically a coordinated climbing turn? And courting disaster doing a chandelle? If you're going to do a commercial ticket you should be familair with spins intimately. An incipient spin shouldn't even make you break a sweat. The answer to the ball question is no. It won't spin. A ball centered airplane in a climbing turn is compensated by rudder and is considered coordinated (in the classic sense). If you introduce a climbing turn stall with the ball centered, you might get a temporary wing drop at the break but unless you introduce a yaw rate as the stall breaks; no yaw rate...no spin! My thought is that we're splitting hairs in this thread. If the airplane is in coordinated flight and stalls straight ahead (no wing drop), a spin can't happen. But on most aircraft, one wing will drop first even if the ball is centered. This wing drop creates a yaw, opening up the possibility for a spin. -- Dudley Henriques The wing drop at a 1g stall is on the roll axis not the yaw axis . You need rudder to induce the yaw rate at the stall necessary to cause entry into auto rotation. -- Dudley Henriques |
#17
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spins from coordinated flight
For the purposes of my question I am referring to coordinated as:
If the horizontal component of lift is exactly equal and opposite the apparent centrifugal force (a coordinated turn). The pilot flying by the "seat of his or her pants" feels no skid or slip with the seat cushion. In your knife edge demonstration you could measure this if you rotated the ball inclinometer 90 degrees. I *believe* it would show you were in coordinated flight. The Websters definition has merit for you when trying to reinforce a fundamental learning objective but I was trying to drive to a very specific question. Apparantly with that I mis used "yaw" Todd "Dudley Henriques" wrote in message news:QMqdnYyufd3QT- Depending on the instructor, you either learn that coordinated flight is with the ball always in the center, or you can be taught that you are coordinated when the control pressures are applied in the exact amount necessary to place the airplane in the sky at the exact configuration required at any instant in time. I prefer the latter definition and have taught my students this way for many years. -- Dudley Henriques |
#18
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spins from coordinated flight
I reviewed the current copy of the Private Pilot PTS and it references
"maintain heading +/- 10 degrees in straight ahead flight, *or* not to exceed 20 degrees ... in turning flight" It would appear that the power on stalls may be demonstrated from straight ahead *or* climbing turns. They are not manditory, at least in the US at the private pilot level. Todd "Neil Gould" wrote in message ... Standard, and _required_ for the practical. I had to do both climbing and descending turning stalls for my checkride. Possibly because I chose to do my checkride in the middle of winter with an 18 kt. breeze and the examiner didn't want to die... ;-) Neil |
#19
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spins from coordinated flight
Dudley Henriques wrote: Todd W. Deckard wrote: I return to the original question: if the ball is in the middle will it spin? If you introduce a climbing turn stall with the ball centered, you might get a temporary wing drop at the break but unless you introduce a yaw rate as the stall breaks; no yaw rate...no spin! There is a possibility that a flip to the outside can occur in a low speed but large bank climbing turn, since the angle of attack of the outboard wing is greater than that of the inboard wing. Thus, in a left climbing turn of 30 degrees or maore bank, the right wing experiences a higher angle of attack, and will stall first if the airspeed drops low enough, and especially if an accelerated stall is induced. I have had this demonstrated tome in a C150. The result is dramatic. The craft flips to the right, as in a half snap roll, ends up upside down, and one is obliged to recover by certain mens. My instructor then practiced much back stick to get back to right side up, managing the zoom safely. It's a bit more of a thrill and happens quicker than a conventional spin. It can be done in both directions, plenty of altitude, please.... NOTE: If you analyze angles of attacks in urns, level, descending, climbing, using a spiral helical surface as reference, you will see that in turning descent, the inner wing experiences a greater angle of attack and will fall safely to the inside of the turn, but when climbing the oppsite wing stalls first. Te flip to upside down is a total surprise. Hence in climbing steeply out of a takeoff, the speed, turn rate and bank must all be carefully managed. Usually, the less the turn rate, the better, the ball must alwys be kept centered and the airspeed must be kept always at least 1.2 Vso or more. A further hint is that in a cross-wind condition, especially when higher level winds are of a changing direction (usually rotates to the right on ascent in the northern hemisphere), it is best to make the first turn into the wind; If you take off of RY270 and the surface wind is from 300, the wind at 200 feet AGL will be from 310 and that at 400 feet AGL will be at 320 degrees, and likely of a higher wind speed. A gradual right turn (10 degrees bank) will present you with increasing airspeed and a more rapid rate of climb; wery safe and very efficient. On descent to landing, opposite things happen. As you descend, the head wind speed diminshes, and in the northern heispere it shifts a bit to the left. Here in Ohio, if there is any significant surface wind, I usually keep about 10 knots extra on early final (if Vso is 60 kts, I carry 70 or 80 kts. When about a half mile from touchdown, I often see a 5 to 10 konot drop in airspeed with no action on my part. Crosswind components accordingly dimiish in speed and shift a bit to the left. A crab angle serves on the first part of final descent. If any significant crosswind remains below 200 feet, a shift into a side slip, where fuselage is aligned with the runway while the upwing wing is down is best for touchdown, often on one wheel for a moment. Angelo Campanella |
#20
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spins from coordinated flight
That is to say "stall reocover while turning and climbing is not mandatory"
"Todd W. Deckard" wrote in message ... They are not manditory, at least in the US at the private pilot level. |
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