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#21
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Stalls and Thoughts
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#22
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Stalls and Thoughts
"Dan" wrote in message ... On Mar 15, 4:33 pm, Dudley Henriques wrote: The analogy "dragging it in" refers to having the airplane configured behind the power curve or if you wish, in the area of reverse command, on final approach....a very dangerous situation. -- Dudley Henriques Dangerous, but certainly useful at times! Such as? (I can think of one instance, but I'd like to know if we're on the same page) |
#23
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Stalls and Thoughts
"Dragging it in" does not necessarily mean "in in the area of reverse
command". It just means that you have added power instead of reducing drag by retracting flaps or gear, etc. "The area of reverse command" is an exteme example. -- BobF. "Matt W. Barrow" wrote in message ... "Dan" wrote in message ... On Mar 15, 4:33 pm, Dudley Henriques wrote: The analogy "dragging it in" refers to having the airplane configured behind the power curve or if you wish, in the area of reverse command, on final approach....a very dangerous situation. -- Dudley Henriques Dangerous, but certainly useful at times! Such as? (I can think of one instance, but I'd like to know if we're on the same page) |
#24
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Stalls and Thoughts
Bob F. wrote:
"Dragging it in" does not necessarily mean "in in the area of reverse command". It just means that you have added power instead of reducing drag by retracting flaps or gear, etc. "The area of reverse command" is an exteme example. The coffin corner of the back side of the power curve is the extreme. You can add power flaps or no flaps and still be well on the front side of the power curve. Generally speaking, if you are "dragging it in, you are most certainly in the area of reverse command -- Dudley Henriques |
#25
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Stalls and Thoughts
Matt W. Barrow wrote:
"Dan" wrote in message ... On Mar 15, 4:33 pm, Dudley Henriques wrote: The analogy "dragging it in" refers to having the airplane configured behind the power curve or if you wish, in the area of reverse command, on final approach....a very dangerous situation. -- Dudley Henriques Dangerous, but certainly useful at times! Such as? (I can think of one instance, but I'd like to know if we're on the same page) I hope he's not thinking of carrier approaches; popular misconception! -- Dudley Henriques |
#26
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Stalls and Thoughts
"Generally"?, "most certainly"?, I'd say "in one case". The other way
around is correct. That is "if you are in the area of reverse command, you are dragging it in". Notwithstanding that the phrase includes the notion of approaching and/or landing. The coffin corner is also not on the back side of the power curve. It is at the asymptote and you can never get into the back side. That's why it a corner. It is certainly not referred to as "dragging it in" there. Been there with the best test pilots in the world in a 747-400 while I was testing the 400. No one has ever referred to is as that. -- BobF. "Dudley Henriques" wrote in message ... Bob F. wrote: "Dragging it in" does not necessarily mean "in in the area of reverse command". It just means that you have added power instead of reducing drag by retracting flaps or gear, etc. "The area of reverse command" is an exteme example. The coffin corner of the back side of the power curve is the extreme. You can add power flaps or no flaps and still be well on the front side of the power curve. Generally speaking, if you are "dragging it in, you are most certainly in the area of reverse command -- Dudley Henriques |
#27
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Stalls and Thoughts
Bob F. wrote:
"Generally"?, "most certainly"?, I'd say "in one case". The other way around is correct. That is "if you are in the area of reverse command, you are dragging it in". Notwithstanding that the phrase includes the notion of approaching and/or landing. The coffin corner is also not on the back side of the power curve. It is at the asymptote and you can never get into the back side. That's why it a corner. It is certainly not referred to as "dragging it in" there. Been there with the best test pilots in the world in a 747-400 while I was testing the 400. No one has ever referred to is as that. You're kidding right? I believe you are repeating wht I have said. I said that "dragging it in" generally refers to flying the approach in the area of reverse command or if you will behind the power curve. This is absolutely correct. Coffin corner is the area behind the curve where sink rate can't be stopped with power but requires reduction in angle of attack. For a perfect example of an aircraft in coffin corner, see the Edwards AFB accident involving a young AF pilot who got his F100 so deep into coffin corner behind the curve he couldn't recover the airplane; not enough air under him to reduce the angle of attack. He applied full burner but couldn't fly it out on power alone. Reduction of angle of attack was what he needed and he didn't have the room. THIS is the definition of coffin corner and it most certainly IS in the area of reverse command. -- Dudley Henriques |
#28
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Stalls and Thoughts
WrongO againO. The "coffin corner" is an altitude (point on a chart where
the stall speed and Mach come together) with a max power setting. If you go faster, you get mach buffet. If you go to slow, you stall. If you reduce power setting, you stall. If you nose over to recover, you mach buffet. With your example I can see why you're confused. -- BobF. "Dudley Henriques" wrote in message ... Bob F. wrote: "Generally"?, "most certainly"?, I'd say "in one case". The other way around is correct. That is "if you are in the area of reverse command, you are dragging it in". Notwithstanding that the phrase includes the notion of approaching and/or landing. The coffin corner is also not on the back side of the power curve. It is at the asymptote and you can never get into the back side. That's why it a corner. It is certainly not referred to as "dragging it in" there. Been there with the best test pilots in the world in a 747-400 while I was testing the 400. No one has ever referred to is as that. You're kidding right? I believe you are repeating wht I have said. I said that "dragging it in" generally refers to flying the approach in the area of reverse command or if you will behind the power curve. This is absolutely correct. Coffin corner is the area behind the curve where sink rate can't be stopped with power but requires reduction in angle of attack. For a perfect example of an aircraft in coffin corner, see the Edwards AFB accident involving a young AF pilot who got his F100 so deep into coffin corner behind the curve he couldn't recover the airplane; not enough air under him to reduce the angle of attack. He applied full burner but couldn't fly it out on power alone. Reduction of angle of attack was what he needed and he didn't have the room. THIS is the definition of coffin corner and it most certainly IS in the area of reverse command. -- Dudley Henriques |
#29
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Stalls and Thoughts
Bob F. wrote:
WrongO againO. The "coffin corner" is an altitude (point on a chart where the stall speed and Mach come together) with a max power setting. If you go faster, you get mach buffet. If you go to slow, you stall. If you reduce power setting, you stall. If you nose over to recover, you mach buffet. With your example I can see why you're confused. I'm not confused and neither are you. :-)) The coffin corner YOU are describing can be found in the flight envelope of the U2 (as well as other airplanes) at high altitude cruise. The coffin corner I'm describing can be found on a dragged in approach AT LOW ALTITUDE with the aircraft behind where the flight test community defines the area of reverse command; that being below the airspeed for maximum endurance. The corner is reached as you get the airplane low enough on the approach where the sink rate can't be stopped with power as maximum is already applied. The ONLY way out of the corner is to reduce angle of attack. If the proximity between the aircraft and the ground won't allow that angle of attack reduction, you hve what we call the "coffin corner". -- Dudley Henriques |
#30
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Stalls and Thoughts
"Bob F." wrote in
: WrongO againO. The "coffin corner" is an altitude (point on a chart where the stall speed and Mach come together) with a max power setting. If you go faster, you get mach buffet. If you go to slow, you stall. If you reduce power setting, you stall. If you nose over to recover, you mach buffet. With your example I can see why you're confused. Acctually, the low side buffet isn't strictly a stall. The proof of this is it happens at a much higher indicated and much lower alpha than a stall at low altitudes. The wing doe lose lift, so in the broadest definition of a a stall the wing stals, but what's actualy happening is that the increased angle of attack you neccesarily have as you reduce speed increases the speed of the air over the wing so that there are localised areas of supersonic flow with an accompanying buffet. So what coffin corner actually is is an onset of mach buffet caused by any combination of speed and alpha. Bertie |
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