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#91
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Head orientation in turns--how is it taught for aviation?
"Maxwell" wrote in
: "Bertie the Bunyip" wrote in message .130... "Maxwell" wrote in A 1g barrel roll can be done, but the required trajectory of the aircraft is not going to be one that is necessarily eye pleasing for ground demonstration purposes. Nope. the only thing you can do at 1 G is straight and level flight. You can keep positive G around a barrel roll, but not 1 G If you enter nose high (enough), and exit nose low (enough), you should be able to maintain close to one g. But then would it still be called a barrel roll. mmm, nope. Not even close., If you fly it really accurately you might be able to keep the entry end exit under two g, but I doubt it. If you fly it very slack, you'll go, at best, Zero G over the top and probably negative. To keep positive G you need well over tow at entry and exit, to keep a little over one as you pass 90deg, then you can probably keep a bit over a half a G over the top and then pretty much the same down the other side. I'll have to admit, I've never specifically watched the g meter while doing so, but if you are sloppy enough, it seems prettly close. I have watched it. Quite a lot, in fact. I've been hearing this story since I've been flying, It was wrong back then and it's wrong now. Even if you dump the nose as you suggest on the way down, you're stil going to have to pay for it eventually...... And on the way up, no way. Bertie |
#92
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Head orientation in turns--how is it taught for aviation?
On 2007-06-11 00:21:38 -0400, Bertie the Bunyip said:
"Maxwell" wrote in : "Bertie the Bunyip" wrote in message .130... "Maxwell" wrote in A 1g barrel roll can be done, but the required trajectory of the aircraft is not going to be one that is necessarily eye pleasing for ground demonstration purposes. Nope. the only thing you can do at 1 G is straight and level flight. You can keep positive G around a barrel roll, but not 1 G If you enter nose high (enough), and exit nose low (enough), you should be able to maintain close to one g. But then would it still be called a barrel roll. mmm, nope. Not even close., If you fly it really accurately you might be able to keep the entry end exit under two g, but I doubt it. If you fly it very slack, you'll go, at best, Zero G over the top and probably negative. To keep positive G you need well over tow at entry and exit, to keep a little over one as you pass 90deg, then you can probably keep a bit over a half a G over the top and then pretty much the same down the other side. I'll have to admit, I've never specifically watched the g meter while doing so, but if you are sloppy enough, it seems prettly close. I have watched it. Quite a lot, in fact. I've been hearing this story since I've been flying, It was wrong back then and it's wrong now. Even if you dump the nose as you suggest on the way down, you're stil going to have to pay for it eventually...... And on the way up, no way. Bertie Bertie is correct. Barrel Rolls are perhaps the most misquoted and misunderstood maneuver done in an airplane. Basically, you can do a barrel roll as loosely or as tight as the airplane's flight envelope will allow. You can also enter a BR from many different flight conditions involving many different g loadings. The main thing to remember about barrel rolls is that they are a 3 dimensional maneuver through 3 dimensional space and that the common denominator in a barrel roll regardless of the g used is that it will remain POSITIVE all the way around. The one exception to this would be after the pull and roll application, you can unload the airplane over the top and drop the g to +1 if you like to loosen the roll rate, but that g must be regained during the recovery. Basically, you will be somewhere over +1g in the entry as you raise the nose, then at some positive +g throughout the roll ranging from as unloaded as you want to loosen up the airplane or as high a positive g and tight a roll as the envelope will allow. As long as the airplane transverses 3 dimensions through the roll, it's a barrel roll. I've done them as loose as a 90 degree change of direction at the top apex in a P51,the F8F, and several jets including the T38, and as tight as a corkscrew in a Pitts S1Sl which was highly loaded with +g and extremely tight. Bob Hoover's rather famous Iced tea stunt in the Shrike is probably responsible for much of the misconception about barrel rolls. He does them fairly loose and with just enough positive g on the airplane to keep the glass from spilling without stressing the airplane. The "secret" to Bob's tea trick is simply his smoothness through the roll as much as keeping positive g on the tea. It's really this smoothness that makes this stunt possible, as although positive g will keep the tea inside the glass. (You can actually POUR tea as you're rolling the airplane but ONLY if you're as smooth as Hoover :-) The reason smoothness is so necessary for the tea trick is that even though you might have positive g on the airplane and in effect doing a barrel roll, if you are not perfectly coordinated through the roll (any excessive yaw for example) your tea will slide off the glare shield laterally and you don't want that......not if you're Bob Hoover anyway :-) So it's positive g for the roll, and smoothness and perfect coordination for the tea stunt. Hope this helps a bit. Dudley Henriques |
#93
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Head orientation in turns--how is it taught for aviation?
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#94
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Head orientation in turns--how is it taught for aviation?
Maxwell writes:
A 1g barrel roll can be done, but the required trajectory of the aircraft is not going to be one that is necessarily eye pleasing for ground demonstration purposes. Any maneuver that involves a change in altitude will involve forces exceeding 1 G at some point. |
#95
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Head orientation in turns--how is it taught for aviation?
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#96
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Head orientation in turns--how is it taught for aviation?
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#97
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Head orientation in turns--how is it taught for aviation?
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#98
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Head orientation in turns--how is it taught for aviation?
JB writes:
Actually, Anthony, ALL of your questions remain unanswered because you refuse to accept the answers when given. Not true. I do get useful answers occasionally. And acceptance or rejection is not an issue. I do occasionally ask questions to which I have the answers (albeit not this one). If a "pilot" answers them correctly, I have reason to believe that he knows what he is talking about, in which case he may be a useful source of answers to questions for which I don't have the answers. It surprises me how few "pilots" can answer the test questions correctly, and so I've had to write off quite a few people in this newsgroup as blowhards. And ALL pilots know infinitely more about aviation than you do because they took the time to learn how to fly in a real plane and usually have years of experience flying. That is a manifestly false assumption; it amazes me that so many pilots cling to it. Since when does 40 hours of experience, mostly trial and error, make anyone an expert at anything? I'm surprised by how many extremely-low-time pilots there are around, too. |
#99
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Head orientation in turns--how is it taught for aviation?
("Viperdoc" wrote)
Now, please proceed to impress us with your knowledge about the vestibular system. Me. Me. Call on me. I know. I know. I should know the answer - after all, I was an alter boy. P-Mont |
#100
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Head orientation in turns--how is it taught for aviation?
Mxsmanic,
Tilt his head 60 or 90 degrees, which most people can do without difficulty. Things are getting better and better. -- Thomas Borchert (EDDH) |
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