F-16 and single piston collide
07-07-2015, 09:44 PM
#31
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Originally Posted by USMCFLYR
When they would come visit us at MCAS Beaufort or Iwakuni - they treated it like an emergency - not having an ILS approach available 
CardioMD - the AoA of a Hornet is 8.1 for an on-speed landing
https://www.youtube.com/watch?v=7fke3t2f-9k
Is that "huge" AoA to you?
The Hornet guys are flying AoA/Ball all the way down, but I'm unsure whether the Viper guys are or not - I didn't think so but I never got a ride in one - only flew the sim.
CardioMD - the AoA of a Hornet is 8.1 for an on-speed landing
https://www.youtube.com/watch?v=7fke3t2f-9k
Is that "huge" AoA to you?
The Hornet guys are flying AoA/Ball all the way down, but I'm unsure whether the Viper guys are or not - I didn't think so but I never got a ride in one - only flew the sim.
Originally Posted by Fegelein
Unless the Cessna was in the notch, the APG-68 should have painted it against the MBC.
Originally Posted by USMCFLYR
I'm not computer literate enough - but somewhere there is a GIF (or something of the sort) of the *double facepalming* with Captain Jean-luc Picard and Number 1 that would be most appropriate here!
07-08-2015, 04:23 AM
#33
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Update
Reports this morning say the 150 was departing MKS (17nm N of CHS) headed to Myrtle Beach. The winds at the time favor Runway 23, MYR is in the opposite direction, so based on the accident site, he was was probably in a climbing right hand turn, just outside of CHS's Class C airspace.
The IR route mentioned by Hacker appears to be very near the accident site.
ps. South Carolina is not just all Trailer Parks, in our large city, we even have indoor plumbing
The IR route mentioned by Hacker appears to be very near the accident site.
ps. South Carolina is not just all Trailer Parks, in our large city, we even have indoor plumbing
Last edited by N9373M; 07-08-2015 at 04:34 AM.
07-08-2015, 05:35 AM
#34
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Originally Posted by cardiomd
........Thus on a Cessna approach lift builds extremely rapidly with increased AOA, drag keeps airspeed low, so the equilibrium point with minimal power at initial approach speeds (say 90-100 kts) is extremely low AOA during approach. With a slip on final Cessna is even further many degrees nose low, pointed toward the ground. We are usually on front side.
The Cessna approaches are at low AOA, often nose-down in attitude. Go back and fly in a 172 with 30 or 40 degrees, they are generally significantly nose-down on final, and the F18/F16 is clearly nose up. Cessna airfoil large lift reserve adds to safety, which is why GA low performance airfoils generally do not need AOA indicators. You guys spend more time "behind the curve" with high induced drag to work that airfoil to get the lift to fly slowly. Compare this to the Hornet.
http://www.youtube.com/watch?v=OEbmeOjG8PQ
The Cessna approaches are at low AOA, often nose-down in attitude. Go back and fly in a 172 with 30 or 40 degrees, they are generally significantly nose-down on final, and the F18/F16 is clearly nose up. Cessna airfoil large lift reserve adds to safety, which is why GA low performance airfoils generally do not need AOA indicators. You guys spend more time "behind the curve" with high induced drag to work that airfoil to get the lift to fly slowly. Compare this to the Hornet.
http://www.youtube.com/watch?v=OEbmeOjG8PQ
Don't confuse pitch angle or "deck angle" with AoA.
ALL airplanes fly on or very near the backside of the power curve for landing. In a GA plane, it is close to the bottom of the curve. This is NOT low AoA just because a Cessna is nose low. In a GA airplane, it is moderate AoA. Short field landing technique? Pretty far back on the curve.....high AoA.
As you note, in a highly wing-loaded jet, you have to work further on the back side of the curve. It is high AoA. To me, 8 degrees of pitch ain't that much. 90 is.
07-08-2015, 10:05 AM
#35
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Originally Posted by N9373M
The IR route mentioned by Hacker appears to be very near the accident site.
Johnson was flying a routine instrument training mission at the time of the incident and was on approach to Joint Base Charleston, Jost said.
07-11-2015, 04:48 AM
#36
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Originally Posted by UAL T38 Phlyer
Doc, stick to medicine.
Don't confuse pitch angle or "deck angle" with AoA.
ALL airplanes fly on or very near the backside of the power curve for landing. In a GA plane, it is close to the bottom of the curve. This is NOT low AoA just because a Cessna is nose low. In a GA airplane, it is moderate AoA. Short field landing technique? Pretty far back on the curve.....high AoA.
As you note, in a highly wing-loaded jet, you have to work further on the back side of the curve. It is high AoA. To me, 8 degrees of pitch ain't that much. 90 is.
Don't confuse pitch angle or "deck angle" with AoA.
ALL airplanes fly on or very near the backside of the power curve for landing. In a GA plane, it is close to the bottom of the curve. This is NOT low AoA just because a Cessna is nose low. In a GA airplane, it is moderate AoA. Short field landing technique? Pretty far back on the curve.....high AoA.
As you note, in a highly wing-loaded jet, you have to work further on the back side of the curve. It is high AoA. To me, 8 degrees of pitch ain't that much. 90 is.
All I'm saying is that approach in a light plane is very nose low. Good visibility. We have a large flare as a result because our high lift wings (steep CL, huge CLmax) needs a large transition to the backside. Shown in the video - I have a very nose low in a standard approach, but an F16 would not. This is not controversial. I agree with you that with the nice elevated vantage point the F16 should have had overall quite good visibility forward.
A potentially steeper approach angle also makes GA craft more nose low (e.g. 5deg approach vs more standard 3) but AOA is also lower at a typical approach speeds with flaps in a cessna as opposed to a high speed airfoil.
Here's a question for you then - why don't fighters generally flare while landing? Correct answer incorporates the concepts above.
07-11-2015, 05:02 AM
#37
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Originally Posted by 80ktsClamp
That would be a quite high AOA for a GA pilot that is used to a flat to slightly negative pitch down final.
8.1 looks about right for the F-16 as it sits similar to the 757 in flaps 25 config or the little bus in flaps 3 config. (that is around 7.5 AOA)
8.1 looks about right for the F-16 as it sits similar to the 757 in flaps 25 config or the little bus in flaps 3 config. (that is around 7.5 AOA)
) is at 50 kts 2 feet above the runway landing with minimal descent or when practicing slow flight. Cessna piston single wings are extremely efficient.
07-11-2015, 05:06 AM
#38
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Originally Posted by cardiomd
Not confusing the two at all. Why don't we stick to discussing aerodynamics?
All I'm saying is that approach in a light plane is very nose low. Good visibility. We have a large flare as a result because our high lift wings (steep CL, huge CLmax) needs a large transition to the backside. Shown in the video - I have a very nose low in a standard approach, but an F16 would not. This is not controversial. I agree with you that with the nice elevated vantage point the F16 should have had overall quite good visibility forward.
A potentially steeper approach angle also makes GA craft more nose low (e.g. 5deg approach vs more standard 3) but AOA is also lower at a typical approach speeds with flaps in a cessna as opposed to a high speed airfoil.
Here's a question for you then - why don't fighters generally flare while landing? Correct answer incorporates the concepts above.
All I'm saying is that approach in a light plane is very nose low. Good visibility. We have a large flare as a result because our high lift wings (steep CL, huge CLmax) needs a large transition to the backside. Shown in the video - I have a very nose low in a standard approach, but an F16 would not. This is not controversial. I agree with you that with the nice elevated vantage point the F16 should have had overall quite good visibility forward.
A potentially steeper approach angle also makes GA craft more nose low (e.g. 5deg approach vs more standard 3) but AOA is also lower at a typical approach speeds with flaps in a cessna as opposed to a high speed airfoil.
Here's a question for you then - why don't fighters generally flare while landing? Correct answer incorporates the concepts above.
In the flare: THEN the viz is poor! T-38: about 0 to 1 degree nose up on final; no-flap approach 3 degrees more. In the flare, 7-8 degrees, no-flap 8-9 degrees (would run out of stab authority). F-4 similar.
I learned to fly in bug smashers long before I joined the Air Force, specifically Cessna as my first three varieties. While flown nose low, vis lateral is poor in the level to up direction. Nose is low, but in 182? That's a big cowl to look around; as I recall (been 28 years), the glareshield is pretty tall, too.
Overall, an F-16 with a pitch of 4-5 degrees on final probably has better FORWARD visibility than a C-182 at -2 or -3 degrees.
Last edited by UAL T38 Phlyer; 07-11-2015 at 05:17 AM.
07-11-2015, 07:03 PM
#40
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For those interested, from the classic “Aerodynamics for Naval Aviators”, section “Basic Aerodynamics”, recapping what I was saying (or trying to ), and a very good intuitive / textual (non-math) summary. Somebody that understands this well will also realize why AOA awareness, particularly the (non)relation to airspeed, is essential for a high-performance aircraft, but markedly less important for Joe Bugsmasher the GA pilot who may rely on surrogate airspeed.
... the high aspect ratio airplane is usually capable of flare without unusual results. The
increase in lift to change the flight path direction without large changes in drag to decelerate the airplane.
The lift and drag curves for a low aspect ratio wing (fig. 1.31) show that at high angles
of attack the lift curve is shallow, i.e., small changes in C, with increased a. This implies
a large rotation needed to provide the lift to flare the airplane from a steep approach. The
drag curve for the low aspect ratio wing shows large, powerful increases in C, with Cr. well
below the stall. These lift and drag characteristics of the low aspect ratio wing create a
distinct change in the flare characteristics.
If a flare is attempted from a steep approach at low airspeed, the increased angle of attack
may provide such increased induced drag and rapid loss of airspeed that the airplane does not
actually flare. A possible result is that an even higher sink rate may be incurred. This
is one factor favoring the use of the “no-flare” or “minimum flare” type landing technique
for certain modern configurations.
[snip]
The effect of the low aspect ratio planform of modern airplanes emphasizes the need for
proper flying techniques at low airspeeds. Excessive angles of attack create enormous
induced drag which can hinder takeoff performance and incur high sink rates at landing.
Since such aircraft have intrinsic high minimum flying speeds, an excessively low angle of
attack at takeoff or landing creates its own problems. These facts underscore the importance
of a “thread-the-needle,” professional flying technique.
), and a very good intuitive / textual (non-math) summary. Somebody that understands this well will also realize why AOA awareness, particularly the (non)relation to airspeed, is essential for a high-performance aircraft, but markedly less important for Joe Bugsmasher the GA pilot who may rely on surrogate airspeed.... the high aspect ratio airplane is usually capable of flare without unusual results. The
increase in lift to change the flight path direction without large changes in drag to decelerate the airplane.
The lift and drag curves for a low aspect ratio wing (fig. 1.31) show that at high angles
of attack the lift curve is shallow, i.e., small changes in C, with increased a. This implies
a large rotation needed to provide the lift to flare the airplane from a steep approach. The
drag curve for the low aspect ratio wing shows large, powerful increases in C, with Cr. well
below the stall. These lift and drag characteristics of the low aspect ratio wing create a
distinct change in the flare characteristics.
If a flare is attempted from a steep approach at low airspeed, the increased angle of attack
may provide such increased induced drag and rapid loss of airspeed that the airplane does not
actually flare. A possible result is that an even higher sink rate may be incurred. This
is one factor favoring the use of the “no-flare” or “minimum flare” type landing technique
for certain modern configurations.
[snip]
The effect of the low aspect ratio planform of modern airplanes emphasizes the need for
proper flying techniques at low airspeeds. Excessive angles of attack create enormous
induced drag which can hinder takeoff performance and incur high sink rates at landing.
Since such aircraft have intrinsic high minimum flying speeds, an excessively low angle of
attack at takeoff or landing creates its own problems. These facts underscore the importance
of a “thread-the-needle,” professional flying technique.
