Re: Re: Riddle me this Batman
enigma said:
I hesitate to speak for fear of confirming that I am in fact a fool. However, I have to take a guess. The balloon traveled 75 miles in 90 minutes, giving a balloon speed of 50 knots.
Assuming that the airmass is completely uniform, that every molecule of air at that certain altitude moved the exact same distance and direction during the duration of the experiment; I don't think that it should really make any difference how fast the airplanes are, only that they are flying at an equal speed. Nor do I think that the wind direction makes any difference versus the aircraft direction, since all three (two airplanes and one balloon) are in the same airmass.
regards,
enigma
YES!
Trophy prize goes to Enigma (ironic isn't it that Ed Nigma was the Riddler in the Batman movie Forever--just saw it on the layover) for answering the question correctly.
Headwind, tailwind, crosswind are all irrelevant. Since speed was the only criteria, and not velocity, direction has no bearing but only the magnitude.
Some assumptions were not spelled out --that the aircraft didn't traverse any weather fronts thus assuming a solid airmass, that speed translated directly to KIAS or what ever shows up your indicator (KCAS), and others were not necessary, i.e. height, color, etc., or even the speed of the aircraft themselves.
Years ago, when the Captain I was flying with posed this question to me, I started writing out D = r x t. I also drew a triangle showing points A and B and two longer sides representing the other two aircraft flight distances. My mistake right away was to reference this to the ground.
Needless to say, I could not determine the time or distance the second aircraft traveled, so I couldn't answer this one.
The Captain, who as a civilian (or as military guys say, has no formal training) was quite an aviator and his life and his wife's life (who is a United 767 Captain) revolve around flying. They have several airplanes (but no kids) and he actively teaches.
He told me one Air Force Engineer type wrote him a
three page letter saying that this problem was
unsolvable!
Needless to say, here's how it works:
Assuming a constant airmass, if you mark a point (deploy a balloon, relative wind speed = zero) and fly away from it for a give amount of time, and have a second leg flying a reverse course (+/- 180) at the same speed through the airmass (KIAS) back to the point, the time is the same, hence 45 +45 = 90 minutes.
The balloon having no speed in the airmass is stationary, but now the speed of the airmass is included with the additional information that the
reference point on the ground has moved 75 miles (it doesn't matter which direction either, the airmass is totally oblivious to how it moves across the ground).
Now you can plug in D = r x t where 75nm = r x 1.5 hours and dividing 75 by 1.5 yields 50nm/hr.
Enigma has gotten all the assumptions correct, and his answer as well and so deserves a hearty
well done in addition to his self-deflating humbleness in answering this query.
Aviation is a wonderful business; I wish I knew more about it.