Question: One of the first passenger jets to enter commercial service was the venerable Boeing 707. What did test pilot Tex Johnston do with a Boeing 707 prototype in front of about 200,000 people, at Seattle’s annual Seafair festival in 1955?
- He broke the sound barrier.
- He flew in so low over Puget Sound that he generated a rooster tail.
- He rolled it.
- knife-edge flight.
The answer is number 3. He actually did it twice; the first time on the way there, ‘to make sure it was okay’.
Subject: To Fly!
Question: Who was really the first American to fly?
- Orville Wright, on December 17, 1903
- George Cayley, 1849
- Jean Blanchard, 1793
- Edward Warren, 1784
The answer is actually number 4. An itinerant entrepeneur named Peter Carnes gave a public demonstration balloon flight in Baltimore in 1784. A 13 year old boy named Edward Warren volunteered his services as the first passenger. He ascended to approximately 200 feet (on a tethered line).
Subject: You take the high road, I’ll take the low road…
Question: What really happens to the air when it is hit by your airplane’s oncoming wing? (We’re talking here just about the air that is in the immediate vicinity of the wing’s leading edge, as well as within a short distance above and below it.
- Any given parcel of air that gets ‘split’ by your wing will of course take two paths. Assuming that you don’t have a symmetrical airfoil and also that the wing is developing some lift, the air that goes over the wing must travel faster than that which goes beneath the flatter surface underneath (since it must travel a greater distance) in order to meet up with it again at the trailing edge. The faster moving air, according to Bernoulli’s Law, is at a lower pressure, and the suction is what pulls you up into the wild blue.
- Well, Number One is close, but incorrect on several counts. First, this Bernoulli thing is a Principle, not a Law. Second, strictly speaking there is no such thing in nature as ‘suction’ (just like there’s no such thing as ‘cold’—it’s just an absence of heat!) But thirdly, and most annoyingly, the air at the top never quite meets up with the air at the bottom because it travels faster, yes, but not fast enough to meet up with the air below it. It lags just a little behind, but due to the elasticity of air it is stretched a bit and lowers the pressure enough to generate lift from below.
- Number Two, but vorticity from the wing tips pulls the ‘upside’ parcel outboard of the lower parcel, so they never actually meet up, anyway.
- Number One is wrong: they don’t meet up. Number Two is right, at least about ‘principles’ and ‘suction’. But actually, the air traveling over the wing can accelerate to almost twice the ‘lower’ parcel’s speed (at lower airspeeds and high cambers, at least) and almost always arrives at the trailing edge ahead of (that’s SOONER than, not in FRONT of) the lower one (as long as lift is being developed).
The answer is number 4… believe it or not!