My regular flight instructor had to deal with some car trouble last thursday, so I flew with this other guy.  We talked a bit about aerodynamics before we went up, and he mentioned something counterintuitive / interesting / tragic about dive-bombers in WWII.

We lost a whole lot of them, which in itself isn’t shocking, but what’s odd is why we lost so many.

The problem wasn’t that:

• They exceeded the do-not-exceed speed of the airframe, ripped it apart, and crashed.
• They were usually headed directly into a hail of high-caliber and/or incendiary ammunition, which riddled / ignited the aircraft and subsequently caused structural failure / more crashing.
• They misjudged their altitude and biffed the target / ocean / ground.

Despite the fact that a dive is the single highest-speed maneuver one can perform in an airplane, the problem was often that they aerodynamically stalled the aircraft while trying to exit the dive.

One of the “flying 101″ definitions that gets drilled into your head is that a stall will occur at any speed, and any gross weight if the angle of attack (the acute angle formed by the wing chord line and the relative wind) exceeds some critical upper limit (ie - the critical angle of attack).

That law makes all kinds of intuitive sense when you consider a plane flying horizontally, then pitching up to exceed the critical angle of attack.  The relative wind in that case is parallel to the earth’s surface, which feels natural.  But it somehow becomes much less intuitive when you consider a plane flying straight down, then pitching relatively-up toward the horizontal plane.  The relative wind in that case is headed straight up, “out of the Earth”-ward.  Irrelevant rationalizations enter your mind, like “he’s still going so fast, and there’s gotta be more relative wind coming from the right, yeah?”  Negative.  The law doesn’t care what direction you’re traveling in, or where the Earth is.  You exceed the critical angle of attack, you stall.

So there you are, some poor bastard in a 1940s-era warbird, hurtling toward Earth and well-armed enemy at somewhere near the speed of God, and you survive long enough to drop your bomb.  “Whew,” you think, “time to GTFO” and jerk back the stick to stop pointing at the ship, the thousands of rounds being fired at you, and the Earth.  Suddenly the controls get all mushy, and just like that you’re no longer hurtling forward, hands first toward the ground at insane speed, but tumbling down, ass first at nearly the same speed.  You can’t see it, but you know it’s coming.

Shitty.

The positive take-away, though, is that a combination of independent study and supervised training under controlled circumstances can allow a man to win battle after battle against unintuitive and potentially dangerous branches of scientific truth.

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