RV-9A and -7A stall testing with wing tufts
RV-9A
http://youtu.be/qeSoO3nXjjI
added as update
RV-7A
http://youtu.be/ECTCVgiBHjA
RV-9A
http://youtu.be/qeSoO3nXjjI
added as update
RV-7A
http://youtu.be/ECTCVgiBHjA
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Can't speak for the -9, but if it is like every other wing I know about there is a washout in angle of attack as you proceed toward the tip. The inboard section has a higher angle of attack and stalls before the tips, allowing aileron control through the stall.
Don
With a subsonic aircraft, the air ahead of the aircraft starts to move a bit before the aircraft gets to it. The air pressure above the wing is lower than the atmospheric pressure - that is a big part of why the wing develops lift. As the wing approaches the air mass, the air ahead of wing starts to rise a bit, as it is "sucked" towards the low pressure area above the wing - this rising air ahead of the wing is called "up wash".
The up wash ahead of the wing causes the angle of attack to be a bit higher than it would be if the air stayed completely still until the wing hit it. With a constant chord wing, the upwash is greatest at the wing root, and lowest at the wing tip. This means the local angle of attack is highest at the wing root, and the stall should start there and progress outboard.
All the above is true for constant chord wings with zero washout. The story changes a bit if the wing is tapered.
You did a lot of work to set up that test and video and I want to thank you. I understand my 9A wing better now ...
Great Video!
The small cameras show many what only one saw before. Knowledge is spread.
The stall as shown seems to be gradual from the trailing edge, for approximately the inboard 1/3 of the wing, then zips out to the tip.
Is that visual stall, what you actually feel yourself?
That is, can you feel and can you control, holding just short of the complete stall, that matches the visual stall?
I will try again, can you see the "drop" with the tuffs as you feel it?