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#11
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Angle of Attack Indicators
Ken S. Tucker wrote:
Referring to sims, I found the AoA indicator of scientific interest to measure airfoil performance, but in shooting landings I relied on the IAS (knots/hr) and vertical airspeed indicator(feet/minute), those together give a rough idea of angle of descent, and one then gets a feeling of AoA from pitch. Yes, you can get a "feel" of AOA from all that, but not enough to fly AOA with the accuracy required in modern carrier operations. A half degree of pitch or a decel/accel trend that you don't see in time could be the difference between a safe landing and a bolter or worse. BTW, IAS is measured in knots, not knots/hr. A knot is a nautical mile/hour, so "knots/hour" would be an acceleration, not a velocity. What might be considered is an instrument that can provide all that info in nice clear form on single gauge at a glance, let's design it. Can't do it; there are too many different types of measurements to be made and displayed. While a velocity vector pointer on a HUD may give a good portion of it, speed is missing... |
#12
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Angle of Attack Indicators
Hi JR.
On Aug 5, 12:22 am, "JRWeiss" wrote: Ken S. Tucker wrote: Referring to sims, I found the AoA indicator of scientific interest to measure airfoil performance, but in shooting landings I relied on the IAS (knots/hr) and vertical airspeed indicator(feet/minute), those together give a rough idea of angle of descent, and one then gets a feeling of AoA from pitch. Yes, you can get a "feel" of AOA from all that, but not enough to fly AOA with the accuracy required in modern carrier operations. A half degree of pitch or a decel/accel trend that you don't see in time could be the difference between a safe landing and a bolter or worse. BTW, IAS is measured in knots, not knots/hr. A knot is a nautical mile/hour, so "knots/hour" would be an acceleration, not a velocity. What might be considered is an instrument that can provide all that info in nice clear form on single gauge at a glance, let's design it. Can't do it; there are too many different types of measurements to be made and displayed. While a velocity vector pointer on a HUD may give a good portion of it, speed is missing... Indicator-instrumentation is subjective, so I'll shoot from the hip. Let DV be rate of ascent, vertically directed, with a length. Let IAS be Indicated AirSpeed be a vector with length and direction. The IAS vector is a hypotenuse, let HAS be Horizotal AirSpeed then IAS^2 = DV^2 + HAS^2 forms a right angle triangle. The IAS and DV come from standard measurements and the HAS is readily derived, so we have Ascent Angle embodied in the IAS vector, (pardon the math). Next, we include Pitch, that is a measurement derived from the artifical horizon. From those the AoA is AoA = Ascent Angle - Pitch. On an actual display, suppose we display the IAS as a vector, with lengths that are colored green, yellow, red, with red-yellow demarking a near stall, as well as the Pitch vector, then at the origin of those displayed vectors, you can print out AoA to .1 degree accuracy, sufficient for most pilots. In my experience, some guys like dials (like clock hands) others like digital, that was a hassle when Volt-Ohm meters went digital, lots of arguments. Personally I like both. The meter provides a sense of rate of change, but the digital provides precison at a glance, so I think the 'AoA' indicator ought to be designed to reflect those concerns and conditions. One question, would you want a g-force indicator? Ken |
#13
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Angle of Attack Indicators
Ken S. Tucker wrote:
Referring to sims, I found the AoA indicator of scientific interest to measure airfoil performance, but in shooting landings I relied on the IAS (knots/hr) and vertical airspeed indicator(feet/minute), those together give a rough idea of angle of descent, and one then gets a feeling of AoA from pitch. Yes, you can get a "feel" of AOA from all that, but not enough to fly AOA with the accuracy required in modern carrier operations. A half degree of pitch or a decel/accel trend that you don't see in time could be the difference between a safe landing and a bolter or worse. What might be considered is an instrument that can provide all that info in nice clear form on single gauge at a glance, let's design it. Can't do it; there are too many different types of measurements to be made and displayed. While a velocity vector pointer on a HUD may give a good portion of it, speed is missing... . . . On an actual display, suppose we display the IAS as a vector, with lengths that are colored green, yellow, red, with red-yellow demarking a near stall, as well as the Pitch vector, then at the origin of those displayed vectors, you can print out AoA to .1 degree accuracy, sufficient for most pilots. While you may have a single display here, you actually have 3 different "gauges": Speed vector, pitch vector, and AOA readout. In my experience, some guys like dials (like clock hands) others like digital, that was a hassle when Volt-Ohm meters went digital, lots of arguments. Personally I like both. The meter provides a sense of rate of change, but the digital provides precison at a glance, so I think the 'AoA' indicator ought to be designed to reflect those concerns and conditions. Modern HUDs (Head-Up Displays) have many readouts on a single display already. As you note, there are many individual preferences, so there is no single "standard" HUD display. You may have some interesting ideas for the display of the information, but the concept is hardly new. One question, would you want a g-force indicator? In a fighter, yes. In a 747, probably not; it would be superfluous. |
#14
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Angle of Attack Indicators
Hi JR.
On Aug 5, 3:28 am, "JRWeiss" wrote: Ken S. Tucker wrote: Referring to sims, I found the AoA indicator of scientific interest to measure airfoil performance, but in shooting landings I relied on the IAS (knots/hr) and vertical airspeed indicator(feet/minute), those together give a rough idea of angle of descent, and one then gets a feeling of AoA from pitch. Yes, you can get a "feel" of AOA from all that, but not enough to fly AOA with the accuracy required in modern carrier operations. A half degree of pitch or a decel/accel trend that you don't see in time could be the difference between a safe landing and a bolter or worse. What might be considered is an instrument that can provide all that info in nice clear form on single gauge at a glance, let's design it. Can't do it; there are too many different types of measurements to be made and displayed. While a velocity vector pointer on a HUD may give a good portion of it, speed is missing... . . . On an actual display, suppose we display the IAS as a vector, with lengths that are colored green, yellow, red, with red-yellow demarking a near stall, as well as the Pitch vector, then at the origin of those displayed vectors, you can print out AoA to .1 degree accuracy, sufficient for most pilots. While you may have a single display here, you actually have 3 different "gauges": Speed vector, pitch vector, and AOA readout. In my experience, some guys like dials (like clock hands) others like digital, that was a hassle when Volt-Ohm meters went digital, lots of arguments. Personally I like both. The meter provides a sense of rate of change, but the digital provides precison at a glance, so I think the 'AoA' indicator ought to be designed to reflect those concerns and conditions. Modern HUDs (Head-Up Displays) have many readouts on a single display already. As you note, there are many individual preferences, so there is no single "standard" HUD display. You may have some interesting ideas for the display of the information, but the concept is hardly new. Right! Even a nerd like me could customize your instrumentation display to exactly what you want and where you want it. Every pilot could have his own ROM, or punch code. Of course the standard stuff would remain fixed, so the ROM is for accessories such as AoA and how it's displayed, IOW's you should get what you want and how you want it. One question, would you want a g-force indicator? In a fighter, yes. In a 747, probably not; it would be superfluous. As a pilot I've banked to 60 degs for 2g's, but in sim's I've pushed it to the black-out limits. I put the g-indicator on the HUD because I think it gives a good feed back for energy bleeding and physiology. If I may ask how many g's have you pulled doing say a 180 turn as in going East then to West? Ken |
#15
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Angle of Attack Indicators
Ken S. Tucker wrote:
One question, would you want a g-force indicator? In a fighter, yes. In a 747, probably not; it would be superfluous. As a pilot I've banked to 60 degs for 2g's, but in sim's I've pushed it to the black-out limits. I put the g-indicator on the HUD because I think it gives a good feed back for energy bleeding and physiology. If I may ask how many g's have you pulled doing say a 180 turn as in going East then to West? The airplanes I flew were limited to 6.5 Gs. I may have exceeded that momentarily on occasion... For fighter airplanes with HUDs, it makes sense to put a G meter up there. I flew them in pre-HUD days, so I had to scan an entire instrument panel... |
#16
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Angle of Attack Indicators
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#17
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Angle of Attack Indicators
On Aug 8, 2:11 am, Dave in Sandy Eggo wrote:
"Ken S. Tucker" wrote in news:56e7269b-a30f-467b- : In my experience, some guys like dials (like clock hands) others like digital, that was a hassle when Volt-Ohm meters went digital, lots of arguments. Personally I like both. The meter provides a sense of rate of change, but the digital provides precison at a glance, so I think the 'AoA' indicator ought to be designed to reflect those concerns and conditions. Slightly OT. I'm a retired cal tech. Regarding the meter thing, all that "precision" wasn't really worth a rat's ass, since the accuracy of many digital VOMs wasn't any better (usually in the 2% - 4% FS area) than the d'Arsonval movement units they replaced. I still use my 25 yo Simpson 260 more than I do my Fluke 77. Dave in Sandy Eggo AT1 USN Ret Ah, nostagia. http://www.simpson260.com/260-1/simpson_260-1.htm I had to use 3-4 digit accuracy for tuning scientific/precision instruments, setting bias etc, so the only way to go was digital. Now I measure batteries to 4 digits, habit I guess. For analog volt measure I usually use Scope channel two set for DC, to get a sense of any ripple, meters are to slow, that way a scope is just like a fast vertical bar display. Ken |
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