Critical angle of attack
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Critical angle of attack
Hello guys,
I just could not find anything in POH nor on the web about critical angle of attack of Cessna 172, 152, PA 28, 34. I know the speeds but what I want to know is the angle at which these types stall in clean configuration and with full flaps.
Thank you for replies
I just could not find anything in POH nor on the web about critical angle of attack of Cessna 172, 152, PA 28, 34. I know the speeds but what I want to know is the angle at which these types stall in clean configuration and with full flaps.
Thank you for replies
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Do you really mean angle of attack, or do you mean something else?
In what way will a pilot measure the angle of attack of his aircraft's wing?
In what way will a pilot measure the angle of attack of his aircraft's wing?
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I really do mean the angle of attack at which those airplanes' wings stall. I know that it is somewhere around 15-20 degrees but as each airfoil has one specific critical angle of attack for given config. I was wondering what the angle was.
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Well 172s and 28s etc have similar aerofoils so I'd assume its
17-18* AoA relative to the chord line of the wing irrespective
of flap. Anyway those types do not come with AoA meters as
standard equipment, so the question's a bit redundant.
17-18* AoA relative to the chord line of the wing irrespective
of flap. Anyway those types do not come with AoA meters as
standard equipment, so the question's a bit redundant.
The Incomplete Guide to Airfoil Usage
Cessna 152: root NACA 2412 tip NACA 0012
Cessna 172 Cutlass: root NACA 2412 tip NACA 2412 mod
Piper PA-28 Cherokee: NACA 65-415
Piper PA-34 Seneca: NACA 65-415
NACA report 824
gives
2412 Clmax (1.5-1.6) at about 16 degrees
64-415 Clmax (1.4-1.6) at 14-16 degrees
for a smooth, unflapped aerofoil, not accounting for 3D effects.
That looks fairly typical.
Cessna 152: root NACA 2412 tip NACA 0012
Cessna 172 Cutlass: root NACA 2412 tip NACA 2412 mod
Piper PA-28 Cherokee: NACA 65-415
Piper PA-34 Seneca: NACA 65-415
NACA report 824
gives
2412 Clmax (1.5-1.6) at about 16 degrees
64-415 Clmax (1.4-1.6) at 14-16 degrees
for a smooth, unflapped aerofoil, not accounting for 3D effects.
That looks fairly typical.
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ShyTorque, In what way will a pilot measure the angle of attack of his aircraft's wing?
a wool fathom and sticky tape outside the side window, and two edding-lines inside
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The Cessna 170A & B had some washout in the wing construction, i.e. reduced incidence (and thus AOA) in the outboard wing. This makes the outboard wing stall last, improving aileron response through the stall. (Various sources quote the amount of washout between one and three degrees).
I expect the derivative 172 has similar washout. Does the PA-28 and its derivatives?
Washout has been a common practice in rigging prewar aircraft as well; it makes the airplane more "honest", albeit with a small potential performance penalty.
Of course, this raises the question "What AOA do you measure to define stall AOA? Root or tip?"
I expect the derivative 172 has similar washout. Does the PA-28 and its derivatives?
Washout has been a common practice in rigging prewar aircraft as well; it makes the airplane more "honest", albeit with a small potential performance penalty.
Of course, this raises the question "What AOA do you measure to define stall AOA? Root or tip?"
glider pilots use "side window pitch strings" for AoA measurement
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I know that we are not interested in AoA once flying. I was just looking for this answer because this was asked at one of the technical interviews another ppruner attended.
I really thank you for all the replies, it helped a lot!
I really thank you for all the replies, it helped a lot!
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glider pilots use "side window pitch strings" for AoA measurement
The OP mentioned having tried to find the information in the POH for the required types. Critical AOA isn't mentioned in those documents because it's impractical for a pilot to measure the wing's AoA.
As we all know, that's why recognition of an impending stall is so important.
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Noox, what interests you more than alpha?
But now I was just interested at what AoA it stalls specifically on 172, Seneca etc.
