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I'm reading "Fate is the Hunter" and just read something interesting. Gann
states that they would climb to 100 feet above their cruising altitude and then descend the 100 feet back down. He called this "flying on the step." He claims that it bought them a few more knots of airspeed. Has anyone heard of this? Is it normal practice? Or is it one of those practices that have been disproven? Personally, I've never heard of this practice. |
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" wrote in message
hlink.net... I'm reading "Fate is the Hunter" and just read something interesting. Gann states that they would climb to 100 feet above their cruising altitude and then descend the 100 feet back down. He called this "flying on the step." He claims that it bought them a few more knots of airspeed. Has anyone heard of this? Is it normal practice? Or is it one of those practices that have been disproven? You might as well have asked about "low wing or high wing". Many people, including those who otherwise have great heads on their shoulders, will swear up and down that "flying on the step" is a real and useful practice. Many others will just as vehemently point out that there's no aerodynamic basis for the claim, and that basic physics argues against it. Peter Garrison wrote a decent article on the topic several years back, and it's come up here every now and then over the years as well. Google Groups can help fill you in on past discussions. Bottom line: if there were really something to it, it would be wide-spread industry and military practice. And yet, all those folks continue to climb to their altitude, accelerate to cruise speed and then throttle back to maintain that speed. I will say this (yeah, I know I already wrote my "bottom line" ![]() great question if for no other reason than it gets people thinking about what the proper sequence of events for climbing and cruising are, as well the the whys and wherefors regarding an airplane's speed versus power relationship. Pete |
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In article k.net,
" wrote: I'm reading "Fate is the Hunter" and just read something interesting. Gann states that they would climb to 100 feet above their cruising altitude and then descend the 100 feet back down. He called this "flying on the step." He claims that it bought them a few more knots of airspeed. Has anyone heard of this? Is it normal practice? Or is it one of those practices that have been disproven? Personally, I've never heard of this practice. Brought back a very old memory of my first visit to the Soviet Union, eons ago (maybe 1969?), being driven in from the airport to a Moscow hotel by a research institute driver who repeatedly accelerated to maybe 50 mph, turned off the engine, coasted back down to maybe 15 mph (with the clutch disengaged), then repeated the process. I was told it was a hangover from WW II days, and many Russians were convinced it substantially increased gas mileage. |
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On Sun, 31 Oct 2004 21:37:46 GMT, "
wrote in k.net:: I'm reading "Fate is the Hunter" and just read something interesting. Gann states that they would climb to 100 feet above their cruising altitude and then descend the 100 feet back down. He called this "flying on the step." He claims that it bought them a few more knots of airspeed. Has anyone heard of this? Is it normal practice? Or is it one of those practices that have been disproven? Personally, I've never heard of this practice. It's an urban legend with roots in sea plane operations. |
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On Sun, 31 Oct 2004 14:19:12 -0800, AES/newspost
wrote: Brought back a very old memory of my first visit to the Soviet Union, eons ago (maybe 1969?), being driven in from the airport to a Moscow hotel by a research institute driver who repeatedly accelerated to maybe 50 mph, turned off the engine, coasted back down to maybe 15 mph (with the clutch disengaged), then repeated the process. This method is still very common with Chinese cab drivers today. At least that's what I'm told by colleagues who regularly vist my company's Chinese plants. Regards Tobias |
#6
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![]() " wrote in message hlink.net... I'm reading "Fate is the Hunter" and just read something interesting. Gann states that they would climb to 100 feet above their cruising altitude and then descend the 100 feet back down. He called this "flying on the step." He claims that it bought them a few more knots of airspeed. Has anyone heard of this? Is it normal practice? Or is it one of those practices that have been disproven? Personally, I've never heard of this practice. There is no "step", but the perception is probably based on achieving cruise speed as quickly as possible after climbing to altitude. The most efficient cruise occurs at a specific airspeed (in reality, angle of attack). Below that speed the airplane is on the back side of the power curve, and faster than that speed, the airplane is wasting fuel... It wouldn't surprise me at all if the transports and bombers in WWII and before tried to cruise at this "sweet spot" to maximize range. So, if they climbed to altitude, set power at cruise, and waited for the airplane to accelerate to cruise speed, they were in for a relatively long wait, and (in theory, at least) would never quite get to the ideal speed. On the other hand, if they accelerated to cruise speed before the power reduction (whether by climbing through, then descending to the cruise altitude, or just by flying to the desired altitude and keeping the power up), they could pull power back to cruise and be right at the sweet spot from the get-go... KB |
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"Larry Dighera" wrote in message
... It's an urban legend with roots in sea plane operations. Actually, other than borrowing the name, the "technique" has nothing to do with seaplane operations. Even those who believe in the concept aren't claiming that the extra airspeed comes from a similar process as that found when getting up "on the step" in a seaplane (where increased performance and reduced drag comes from lowering the surface area contacting the high-drag water surface). |
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![]() " wrote in message hlink.net... I'm reading "Fate is the Hunter" and just read something interesting. Gann states that they would climb to 100 feet above their cruising altitude and then descend the 100 feet back down. He called this "flying on the step." He claims that it bought them a few more knots of airspeed. Has anyone heard of this? Is it normal practice? Or is it one of those practices that have been disproven? Personally, I've never heard of this practice. I believe flying "on the step" has been checked out quite well and found to have no validity. John Lowry Flight Physics |
#9
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Gann
states that they would climb to 100 feet above their cruising altitude and then descend the 100 feet back down. He called this "flying on the step." He claims that it bought them a few more knots of airspeed. Makes no sense to me... that is, if you mean this as a continuous process (up, down, up, down). Once you are at the most efficient speed (however you define it), deviating from that speed in either direction reduces efficiency. In terms of energy, you get back all the energy of the climb in the descent - but no more. However, you dissipate (waste) more energy due to friction at the higher speed, which is when you are regaining the energy you spent to climb to the higher altitude. Friction goes up as the square or the cube of the velocity (depending on the realm), which means you lose more going faster than you gain going slower. So the best way to achieve a certain average speed is to fly at that speed. Jose -- for Email, make the obvious change in the address |
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