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"Tony Cox" news:195307d0.0206011017.307c5d5f@posting.google.com... > > Do people really think that the velocity of a steady state air mass has > an effect on plane performance? Welcome back. :) As for that question...unfortunately, yes. There are a few people around who do believe that. I take it you werent following this newsgroup last year when AcroCFI was making his rounds? > The figures I stated come from assuming a wind increase of 3mph per > 100 ft. If it were 6 mph, the effect would be almost doubled. Ive just > posted the analysis to let others see if it makes sense. And yes, Ill > retract if someone can find errors! If my plane went 300 knots instead of 150 knots, Id get there in half the time! I fail to see your point...my apologies, as I dont mean that in a mean way. A 3 mph/100 ft gradient isnt typical, so talking about *doubling* the gradient isnt really going to help things. Even with a 3 mph/100 ft gradient, youre looking at a wind speed change from 0 to 30 knots over 1000 feet. Does that happen? Sure, anythings possible. Does it happen a lot? No, at least not in most places. Usually when its windy aloft, its windy at the ground too. The winds calmer at the ground, almost always, but its not zero. As uncommon as 3 mph/100 ft is, a gradient of 6 mph/100 ft is going to be vastly even more rare. Dangerous when it happens, no doubt. But frankly, with a gradient that steep, an increasing tailwind is going to be the least of the pilots worries...thats going to come with some pretty nasty turbulence as well. I dont really see anything wrong with your analysis per se. Its the conclusions drawn that I would prefer to play down. Note that I dont even disagree with the conclusions, as far as they are objective. Its just that the subjective part of your conclusions are overstating the risk, IMHO. Given that that part is subjective, I will admit that if you feel its a major risk and I feel its not, its probably best to just leave it at that. I dont really have a need to argue this thing into the ground with you, especially since I am in agreement with the underlying physics of the situation. I think weve discussed it enough and other pilots can take the hard numbers and decide for themselves whether its a serious risk for them or not, taking the subjective part of the discussion into their own hands. Okay? :) Pete |
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