Plane & Pilot
Thursday, May 1, 2008

Wingipedia, Part II

In this edition, “Jenny” through “roll”

wingipediaLast month, we brought you the first installment (“acrobatics” through “induced drag”) of Wingipedia, our aviation-based encyclopedia. Here, we present the second installment. If you think that something’s missing, log on to to contribute your own additions.
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When pilots or engineers refer to “q,” they’re using a coefficient that relates to the efficiency of the air going over a surface. Part of what affects that efficiency is speed (it’s a squared function) and the relative air density. So fast-moving, denser air gives a higher-efficiency surface.

Q-Star (Lockheed, Vietnam)
The Lockheed YO-3 Q-Star program was an effort to produce an extremely quiet aircraft for night reconnaissance in Vietnam. Starting with Schweitzer 2-32 gliders, a bizarre series of airplanes turning huge, slow-turning propellers were developed. According to witnesses, you couldn’t hear them overhead at pattern altitude.

Q-tip propeller
The tips look as if you’ve done a gear-up landing because they’re bent 90 degrees. They reduce the propeller diameter, thereby decreasing prop noise, while moving the tip vortices out in such a way that efficiency is supposedly increased.

Queen Air
The Queen Air was the cabin-class step up from the Beech Twin Bonanza and used essentially the same wing. Powered by IGSO-480 and IGSO-540 Lycomings (geared, supercharged), the engines didn’t win any popularity contests, but the airframe led to the King Air when turbines were installed, and a legendary aircraft was born.

Roll (aerobatic)

The first quantum leap in U.S. fighter design in several decades, it may well be the last, given changing world-combat requirements. The airplane is practically invisible to prying electronic eyes, can maneuver like a humming bird, packs a lethal punch and costs as much as the gross national product of many small countries.

Relative bearing
The relative bearing is a direction as measured off the nose of the aircraft. For instance, a 30-degree bearing is 30 degrees to the right of the nose. Relative bearing relates only to the airplane itself and has no relationship to any other form of heading (magnetic, compass heading, etc.).

Risk is what we try to manage throughout every aspect of a flight. Just being off the ground in a machine is a risk, but through skill and planning, all aspects of that risk can be managed.

Roll (aerobatic)
A complete 360 maneuver around the longitudinal axis, the primary variations on the roll are the aileron roll (1 G, nose descending); slow roll (-1 G, nose on a given reference); barrel roll (1.5 to 2 G’s, nose going around a point 45 degrees off-axis); and snap roll (high-speed stall into a horizontal spin). They’re all fun!

Wingipedia, Part I ("acrobatics" through "induced drag")

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