Question: The growth of hail stones can continue as long as there are updrafts strong enough to keep them aloft. What is the largest hail stone ever recorded?
- On March 10, 1939, at Hyderabad India, the heaviest hailstone ever recorded fell, and it weighed 7.5 pounds. (The diameter was not reported, however this would imply a diameter of approximately nine inches.)
- on September 3, 1970, in Coffeyville, Kentucky, about 5.5 inches in diameter (slightly larger than a softball), weighing 1.67 pounds, and it was estimated to have struck the ground at 105 MPH
- in Potter, Nebraska, on July 6, 1928: its diameter just under 5 and a half inches, and its weight was 1.51 pounds
- On April 17, 1998, 4.5 inch diameter hail fell in Carnes Mississippi, and there were unofficial reports of golfball to softball sized hail in other locations.
Answer: B. The event in choice A is urban legend and has not been substantiated.
Subject: ‘And for my next number…’
Question: Why would aerobatic stunt pilots do headstands during training?
- For short periods afterwards, this increases oxygen flow to the brain, which helps prevent loss of consciousness during high-g maneuvers.
- to increase the storage capacity of major blood vessels in the upper body, particularly the head, which helps prevent blackouts during high-g maneuvers
- to acclimate the body to the upward surge of blood that occurs during negative g maneuvers
- to gain proprioceptive familiarity with reversed outside references, or to put it less clinically, to get used to being upside-down
Answer: C. Aerobatic pilots must deal with negative as well as positive g’s. The familiar positive g’s occur when flying maneuvers like a normal loop, where blood drains from the head and pools in the feet. Some pilots lose color vision or acuity, since the eyes are very sensitive to oxygen level. For others, vision stays sharp, but narrows, and although their thinking is not impaired, one minute they’re marveling at their sudden tunnel vision, and then it’s lights out. (This is G-LOC, or ‘g-induced loss of consciousness.’) Uncle Sam provides ‘anti-g suits’ to its pilots, but flying ‘outside’ loops poses a reverse challenge, with blood now rushing to the head, risking nose bleeds or burst vessels. Negative-g’s are more difficult to nullify. (You can’t strap a g-suit on your head.) So one preventive measure, as funny as it looks, is for pilots to do headstands and handstands to condition themselves for that headward blood surge (or go to the nearest tot lot and hang from the monkey bars). Can’t say that I’ve ever seen it, though…
Subject: The Forgotten Ancestor of the Osprey
Question: The concept of powered lift aircraft is not new. Aircraft such as the V-22 had a much earlier progenitor. This aircraft was:
- an experimental ultralight aircraft, the XL-161A, which was developed in 1971, and intended for tactical interdiction. It could remain aloft for only 30 minutes, but despite the fact that there were no injuries of any kind during testing, it was scrapped.
- a V/STOL cargo & troop transport intended for combat support. The XC-142A could carry 8000 lbs at over 400 mph, as well as in a hover. The first prototype was delivered in 1965, and the 142A made the first V/STOL landing on an aircraft carrier. However due to handling difficulties and accidents, the aircraft was cancelled.
- the XV-3, first flown in August 1955. It had a slender, fixed, mid-fuselage wing, with large rotors on each wing tip. The rotors were vertical for take-off, landing, and hover, and rotated horizontally for forward flight, while the wing remained fixed.
- the XV-15, which was the true ‘proof of concept’ progenitor for the V-22, with prop-rotor engine pods mounted on wingtips, like the V-22. It first flew in October 1980.