The 2424 just happened to be the first airfoil in the figures I've taken from the NACA website which has good old 824 online.
And it's -almost- symmetrical, fat little bugger that it is.
The 44xx series has a much higher Cm, while the 230xx cambered sections have almost none, which is probably why they were popular way back when.
It's been 40 years since I flew a Taurus.. still have the plans, but can't get up the enthusiasm.
I'd have to change it too much.
Don't like bolt-upright motors sticking out the top of the fuselage.
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Figure 4 eliminates everything -but- what is changed to begin a dive. The tail down load.
Diminishing this lets the pitching moment push the nose down. About what happens when doing the "dive test" with an aft c.g.
Sometimes it's the LAST test that airplane will do!
Even full-up can't save a plane in many instances, once the tuck starts.
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" Figure 5 is close but he has assumed the the negative pitching moment due to camber is equal to the lift times its moment arm. Ain't necessarily so. If you have camber (and perhaps some flap) just right it can happen but it is not a given."
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The figure states the situation for -A- flight condtion.. change condition, tail load changes... that's the given for that situation.
The lift on the horizontal is admittedly small for balancing the pitching moment, but wing lift ahead of the c.g. can only "remove" the pitching force at one speed, Cm being a constant independent of Alpha for most cases, while obeying the v^2 rule as Cl and Cd do.
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