Question: A ‘prester’ is another name for
- a dust devil
- a waterspout
- a tsunami
- a chinook wind
Answer: B. It’s another name for a waterspout, which is just a tornado over water. Waterspouts incidentally move more slowly, due to their greater weight. (Water is heavy!) They also break up sooner, for the same reason (and the greater inertia of water which, when slung around in a circle, wants more to continue off in a straight line).
Subject: Pushing the Limits
Question: The (positive) limit load factor for a normal category airplane is
- 3.8, but only below V(subscript: NO), the maximum structural cruising speed
- 3.8, or 4.4, if it is operated in the lighter ‘utility’ category
- A and B
- usually 3.8 (with the stipulation in A), but for certain normal and commuter aircraft, it could be as low as 2.2!
Answer: D. Choice A is true, because that load factor goes from 3.8 to just one between maximum structural cruising speed at never-exceed speed. And choice B is true for many normal category aircraft, but not all. As far as the surprising statement in choice D goes, for heavier aircraft (potentially, any aircraft grossing over 4117 pounds) Title 14 CFR Part 23.337 actually states that the positive limit maneuvering load factor for normal and commuter aircraft may not be less than 2.1 + [24,000/(W+10,000)]. Conceivably if there were a normal category airplane that weighed 300,000 pounds, the load factor might be +2.2 (though actually most transport category airplanes are limited to +2.5). It also states that the positive load factor need not be more than 3.8, and the negative load factor may not be less than 0.4 times the positive load factor for normal, utility, and commuter categories. (For the utility category, the positive load factor of course is 4.4; for aerobatic airplanes, it’s 6.0; and the ‘negative’ coefficient for aerobatic airplanes becomes 0.5, not 0.4.)
Subject: Land of the Gentle Zephyr
Question: With the anticipated Sport Pilot ruling, those folks who enjoy flying ultralights, powered parachutes, and any other aircraft that are less tolerant of gusts and sudden upsets, it might be useful to know where in the US one might find the lowest (or to put it another way) most gentle winds. Hence this question: Which city in the United States is the least windy?
- Medford, Oregon
- Jackson, Mississippi
- Sacramento, California
- Oak Ridge, Tennessee
Answer: D. The average wind in Oak Ridge, Tennessee is about four knots! Although this NOAA climate map doesn’t reveal very low-level details such as city by city, as you can see this does agree on at least a regional level. Oak Ridge lies in a valley bounded by the Great Smoky Mountains to the southeast and the Cumberland Mountains to the northwest, which helps explain the shelter effect from prevailing westerly winds. That is one of the reasons that the United States’ nuclear development was done at Oak Ridge; if there were an accident, the wind would not carry the radioactive particles as far as in other places.