Which is the chord line of this aerofoil, as used on the Whirlwind?
Answer: C. Yes, me too. Turns out that ‘Leading Edge’ didn’t mean the same to NACA back then as it does to the rest of us now. Fortunately we have a very capable chap called Gunnar who worked out why things weren’t fitting when we used ‘b’ as the chord.
By: Beermat - 21st December 2012 at 16:29
I don’t know about the former, but yes, the latter is absolutely right – the way the curve is drawn, adding camber ‘distorts’ the symmetry and brings the ‘actual’ leading edge forward. The plotting reference line was kept as the chord, even though it looks wrong.
Nothing on the Whirlwind is as it seems.
By: Graham Boak - 21st December 2012 at 15:54
Just guessing really, but is C the stagnation point of the airflow at zero incidence? Or perhaps the tip of the chord of the aerofoil before adding camber? (Or could these actually be the same thing?)
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December 21, 2012 at 3:49 pm