He should know better, it is bad science. He must read the pulp fiction type of presentation that was and still is wrong. He then assumes that since he is a good computer guy that anything he comes up with on aerodynamics is right too, apparently without reading any accurate literature on the subject. The first MacIntosh was a marvel and I had one at home and at work. I am a fan of his work regards to computing and have had a version of nearly every Apple computer since the Apple I. Six hard drives, tons of ram, more power (insert Tim the Tool Man's grunt here). HighPlains - actually this is being written on the fastest G5 mac that money can buy. Presently retired, Active RC modeler for 40+ years. at McDonnell Douglas working on F-4, F-15, F-18 and other projects. I am one such person, there are many that are much better qualified than I am that would be more than happy to look over your articles before publishing.Īero Dept. Next time you feel like publishing something approaching the science of aerodynamics how about running it by an aero engineer to check it for accuracy? It would only take a minute and stop the efforts of people like Jeff who are just wrong. The integral of those pressure fields is, not surprisingly to us, the total lift that is measured on the model by its internal strain gauge balances. I have been an aeronautical engineer for 40 years and have been involved in numerous wind tunnel tests where pressure taps were put on the top of the wing to measure and analyze these pressure fields on the wing. The wing can be moved only by a Force, remember Force = mass x acceleration (remember that a force is needed to counter the gravity acceleration for level flight). The differential in pressures is the direct cause of lift on the wing. Those variations result in a pressure field that is lower on top of the wing and higher on the lower surface of the wing. The wing lift is produced as a result of the angle of attack of the wing causing flow variation in the air. Jeff is just, oh, so wrong! If you paid him for the article you just got swindled!! Not that it is the result of metabolic processes that allow the elephant to move, not the muscles and the "combustion" processes that convert sugars into energy in the cells of the body controlled by an elegant set of nerve cells. Jeff's approach is like seeing a pile of elephant poop and saying that it is what causes the elephant to move. He looks at what happens AFTER the lift has been produced by the wing and says that is the lift mechanism. But he ignores the basic lift mechanism of the wing. He is saying that the wing moves air down, and therefore the wing goes up. Its simple - Mass exhaust x acceleration of exhaust = Force of exhaust (which is reacted on the rocket nozzle as a force) That force on the nozzle is a Force on rocket = Mass rocket x acceleration of rocket. But only because they are connected by F=ma. Mass rocket x acceleration of rocket = Mass exhaust x acceleration of exhaust. Then along comes Jeff and throws the whole thing in the garbage can with his concept that we don't have to worry about that, it is just the reaction to the downwash, like a rocket exhaust, that causes the lift. There are hundreds of studies about shaping the wing to optimize the wing shape to maximize the efficiency of the wing to make these pressures. Thousands of aero engineers have been hard at work for 100 years studying the pressures above and below the wing and getting PHD's based on the math and knowledge of how the differential pressures on the wing are the direct cause of lift on the wing. To say that the downwash is the mechanism of lift is totally wrong - that is like saying the tail wags the dog! Then he says, "The wing moves air down, and therefore the wing goes up for the same reason a rocket goes up when it sends gasses down". He spends 85 percent of the article talking about the concept that the popular explanation of lift in books have had this wrong for years (Note that this is not what is in any modern text book used by professionals in the field). Isn’t anyone at Fly RC bothered by the total lack of science and accuracy put out by Jeff Raskin in the April issue? He is right only on one point - that the air molecules don't have to come together at the trailing edge of the airfoil. Has anyone else read the article by Jeff Rankin in April Fly RC magazine? Here is what I wrote to them. I wrote this letter to Fly RC this morning while I was still ranting and cursing. I am having a lot of difficulty trying to "resist the urge to curse, flame, degrade, insult or embarrass someone in your post".
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