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On Dec 20, 9:42 am, "kirk.stant" wrote:
....snip... Obviously, my opinion is colored by having actually flown airplanes with excellent AOA systems, and by my wish to optimise my soaring for XC and racing. ....snip... Cheers, Kirk Kirk, Could you summarize for me _how_ you used the AOA indicator in those aircraft, which aircraft and under what conditions ? I am curious to the actual use(s). Thanks Todd Smith 3S |
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Kirk,
Could you summarize for me _how_ you used the AOA indicator in those aircraft, which aircraft and under what conditions ? I am curious to the actual use(s). Thanks Todd Smith 3S Sure. I used AOA in T-38s (a little - not much flight time in those) and in F-4s (about 2000 hours in those). In my current job, I fly a variety of F-15 simulators (the real thing, not PC games) and use AOA all the time. Have also a few flight in F-16s and a lot of time in F-16 simulators, which use AOA in the approach and landing configuration. In a nutshell, AOA is used anytime optimum performance is required from the wing - be it turning, flying an approach, flying for max range, recovering from a dive, etc. Since fighters can vary weight a lot due to fuel burn and store (weapons) configuration, it's impractical to try to use airspeed other than as a general guide to your energy state - your airspeed tells you how much instantaneous energy you have to maneuver, then you fly at the AOA that matches the type of turn you want - less AOA is conserves energy, more AOA turns faster, etc. If you are flying for max range or max endurance, again there is a recommended AOA to fly at - it will stay the same while the actual airspeed changes based on gross weight, configuration, and altitude. Finally, in the pattern, you figure out the approximate airspeed and AOA based on fuel and stores remaining, then crosscheck the two - if they agree, it's easier to fly AOA on most jets (F-4 especially, F-15 less so). Now, compared to gliders, these are all extremely low aspect ratio, and that will exaggerate AOA effects. But the aerodynamic priciples are the same. Finally, someone questioned about whether it's better to thermal efficiently or in the best part of the themal. The answer, IMHO, is that you should strive to do both. Right now we have wonderful instruments to help us find the best lift. But we still use a crude instrument to fly efficiently. Well, actually, most people probably thermal more by feel and attitude than by staring at the airspeed indicator. End of war story. Cheers, Kirk |
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On Dec 20, 5:17 pm, "kirk.stant" wrote:
Sure. I used AOA in T-38s (a little - not much flight time in those) and in F-4s (about 2000 hours in those). In my current job, I fly a variety of F-15 simulators (the real thing, not PC games) and use AOA all the time. Have also a few flight in F-16s and a lot of time in F-16 simulators, which use AOA in the approach and landing configuration. Excellent post Kirk. I was about to ask if anyone had fighter-jet experience and you do! I was going to ask as I recall that in an accident report on a fatal stall/spin after a missed approach to a carrier by a F-14 one of the key aspects had been the crew's monitoring of the AoA. IIRC - though I'm not sure I do - the rear-seat crew member actually calls out the AoA to the front-seat pilot, who has too many tasks to do to also include checking the AoA in their scan. Finally, someone questioned about whether it's better to thermal efficiently or in the best part of the themal. The answer, IMHO, is that you should strive to do both. Right now we have wonderful instruments to help us find the best lift. But we still use a crude instrument to fly efficiently. Well, actually, most people probably thermal more by feel and attitude than by staring at the airspeed indicator. I was thinking the same thing. I have often wondered about the best speed to fly at any given moment when thermalling, including using that online calculator thing to get some guidelines which were a fair bit faster than I thought they would be. As you say, it's odd that we have great varios, but nothing very good to get the most from our wings. I'd be interested in an AoA indicator for performance reasons, but not so much for safety, where I personally think a good safety margin on the ASI does the job (plus not leaving it too late to have to pick a small field to land in, so ground-roll distance is such a factor). Dan |
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On Dec 20, 12:17 pm, "kirk.stant" wrote:
Kirk, Could you summarize for me _how_ you used the AOA indicator in those aircraft, which aircraft and under what conditions ? I am curious to the actual use(s). Thanks Todd Smith 3S Sure. I used AOA in T-38s (a little - not much flight time in those) and in F-4s (about 2000 hours in those). In my current job, I fly a variety of F-15 simulators (the real thing, not PC games) and use AOA all the time. Have also a few flight in F-16s and a lot of time in F-16 simulators, which use AOA in the approach and landing configuration. In a nutshell, AOA is used anytime optimum performance is required from the wing - be it turning, flying an approach, flying for max range, recovering from a dive, etc. Since fighters can vary weight a lot due to fuel burn and store (weapons) configuration, it's impractical to try to use airspeed other than as a general guide to your energy state - your airspeed tells you how much instantaneous energy you have to maneuver, then you fly at the AOA that matches the type of turn you want - less AOA is conserves energy, more AOA turns faster, etc. If you are flying for max range or max endurance, again there is a recommended AOA to fly at - it will stay the same while the actual airspeed changes based on gross weight, configuration, and altitude. Finally, in the pattern, you figure out the approximate airspeed and AOA based on fuel and stores remaining, then crosscheck the two - if they agree, it's easier to fly AOA on most jets (F-4 especially, F-15 less so). Now, compared to gliders, these are all extremely low aspect ratio, and that will exaggerate AOA effects. But the aerodynamic priciples are the same. Finally, someone questioned about whether it's better to thermal efficiently or in the best part of the themal. The answer, IMHO, is that you should strive to do both. Right now we have wonderful instruments to help us find the best lift. But we still use a crude instrument to fly efficiently. Well, actually, most people probably thermal more by feel and attitude than by staring at the airspeed indicator. End of war story. Cheers, Kirk Kirk, I understand (in theory) how you would fly at an optimal AOA, but I was hoping for a more procedural idea on how to use an AOA indicator. Do you use it like a "control instrument", like an attitude indicator, or a "perfomance instrument", like the airspeed ? Todd 3S PS. It sounds like you work at some training or simulation development group for Boeing, St Louis ? |
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I think this entire thread can be summed up as follows:
If you have had the opportunity to fly with an AOA for an extended period of time ... you would like to have one in your sailplane. If you haven't had the opportunity to fly with an AOA ... you don't seen the need or value. Beyond that, all this discussion is academic and I am getting tired of the thread. Respectfully, Wayne HP-14 "6F" A-3B SkyWarrior / A-6A Intruder Bombardier who has observed 1000+ carrier landing from the cockpit. P.S. I would like to have an AOA in my old HP-14. http://www.soaridaho.com/Schreder "kirk.stant" wrote in message ... Kirk, Could you summarize for me _how_ you used the AOA indicator in those aircraft, which aircraft and under what conditions ? I am curious to the actual use(s). Thanks Todd Smith 3S Sure. I used AOA in T-38s (a little - not much flight time in those) and in F-4s (about 2000 hours in those). In my current job, I fly a variety of F-15 simulators (the real thing, not PC games) and use AOA all the time. Have also a few flight in F-16s and a lot of time in F-16 simulators, which use AOA in the approach and landing configuration. In a nutshell, AOA is used anytime optimum performance is required from the wing - be it turning, flying an approach, flying for max range, recovering from a dive, etc. Since fighters can vary weight a lot due to fuel burn and store (weapons) configuration, it's impractical to try to use airspeed other than as a general guide to your energy state - your airspeed tells you how much instantaneous energy you have to maneuver, then you fly at the AOA that matches the type of turn you want - less AOA is conserves energy, more AOA turns faster, etc. If you are flying for max range or max endurance, again there is a recommended AOA to fly at - it will stay the same while the actual airspeed changes based on gross weight, configuration, and altitude. Finally, in the pattern, you figure out the approximate airspeed and AOA based on fuel and stores remaining, then crosscheck the two - if they agree, it's easier to fly AOA on most jets (F-4 especially, F-15 less so). Now, compared to gliders, these are all extremely low aspect ratio, and that will exaggerate AOA effects. But the aerodynamic priciples are the same. Finally, someone questioned about whether it's better to thermal efficiently or in the best part of the themal. The answer, IMHO, is that you should strive to do both. Right now we have wonderful instruments to help us find the best lift. But we still use a crude instrument to fly efficiently. Well, actually, most people probably thermal more by feel and attitude than by staring at the airspeed indicator. End of war story. Cheers, Kirk |
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On 20 Dec, 18:18, "Wayne Paul" wrote:
I think this entire thread can be summed up as follows: If you have had the opportunity to fly with an AOA for an extended period of time ... you would like to have one in your sailplane. Doesn't follow. Just because one person who has flown with an AoA indicator would like one in his glider does not mean that every who has would. Ian |
#7
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Ian wrote:
On 20 Dec, 18:18, "Wayne Paul" wrote: I think this entire thread can be summed up as follows: If you have had the opportunity to fly with an AOA for an extended period of time ... you would like to have one in your sailplane. Doesn't follow. Just because one person who has flown with an AoA indicator would like one in his glider does not mean that every who has would. Ian I haven't (had the opportunity to fly w. an AoA indicator)...but I would (like one in my [flapped] sailplane). That noted, I do tend to agree w. Wayne there's an awful lot of 'religious belief' (subliminal ax-grinding, etc.) being repeated in this thread that 'en-murkens' its intrinsic value. Regards, Bob - instrumentational minimalist - W. P.S. With a bow to Thread Creep (and Winter, dry laugh)...as fascinating a topic as AoA is, and as much as it affects the aerodynamic behavior of wings, equally fascinating (to me, anyway) is the gamut of human responses the topic has so-far illuminated. It ranges from well-intentioned 'educators,' to inexperienced 'strong holders of opinion skeptically resistant to change from instrumentational status-quo.' We all know who we are! What's fascinating to me is: What is it about 'topics' that leads to stark opinional divergences as: a) this 'AoA discussion' vs. b) the almost manic avidity underlying GPS overwhelm-ment of the (previously widely held, and,) rule-forbidden resistance to navigation aids in both badge and contest venues? I mean, w. the PW5 and silicone-in-wax topics, we can at least sense the underlying reasons for rabidity, but I'm struggling in this case! There. My one attempted contribution to Northern Hemisphere Winter ROTS (Rabidity of Topics Syndrome). |
#8
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Ian wrote:
On 20 Dec, 18:18, "Wayne Paul" wrote: I think this entire thread can be summed up as follows: If you have had the opportunity to fly with an AOA for an extended period of time ... you would like to have one in your sailplane. Doesn't follow. Just because one person who has flown with an AoA indicator would like one in his glider does not mean that every who has would. Ian I haven't (had the opportunity to fly w. an AoA indicator)...but I would (like one in my [flapped] sailplane). That noted, I do tend to agree w. Wayne there's an awful lot of 'religious belief' (subliminal ax-grinding, etc.) being repeated in this thread that 'en-murkens' its intrinsic value. Regards, Bob - instrumentational minimalist - W. P.S. With a bow to Thread Creep (and Winter, dry laugh)...as fascinating a topic as AoA is, and as much as it affects the aerodynamic behavior of wings, equally fascinating (to me, anyway) is the gamut of human responses the topic has so-far illuminated. It ranges from well-intentioned 'educators,' to inexperienced 'strong holders of opinion skeptically resistant to change from instrumentational status-quo.' We all know who we are! What's fascinating to me is: What is it about 'topics' that leads to stark opinional divergences as: a) this 'AoA discussion' vs. b) the almost manic avidity underlying GPS overwhelm-ment of the (previously widely held, and,) rule-forbidden resistance to navigation aids in both badge and contest venues? I mean, w. the PW5 and silicone-in-wax topics, we can at least sense the underlying reasons for rabidity, but I'm struggling in this case! There. My one attempted contribution to Northern Hemisphere Winter ROTS (Rabidity of Topics Syndrome). |
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