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#21
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Myth: 1 G barrel rolls are impossible.
Jim Logajan wrote
Most everyone agrees that keeping the coffee in the cup is possible. What some people don't seem to believe is possible is that the force felt by the pilot (or tea/coffee) can be 1 gee during the entire roll. They believe it has to vary during the roll. I'm hesitant to name names. ;-) My name is Bob Moore :-) Just what is a barrel roll has been debated between "Big John", Dudley, and myself at least twice in the past. It IS difficult to describe without having a model airplane in one's hand and flying it through the maneuver. How come you don't seem to belive the following from Wikipedia? Barrel roll From Wikipedia, the free encyclopedia This article is about the aerial sport. For the military operation, see Operation Barrel Roll. A barrel roll occurs when an object (usually an airplane or roller coaster) makes a complete rotation on its longitudinal axis while following a helical path, approximately maintaining its original direction. The G load is kept positive (but not constant) on the aircraft throughout the maneuver, commonly not more than 2-3 G. In aviation, the maneuver includes a constant variation of attitude in all three axes, and at the midpoint (top) of the roll, the aircraft is flying inverted, with the nose pointing at a 90-degree angle ("sideways") to the general path of flight. The term "barrel roll" is frequently used, incorrectly, to refer to any roll by an airplane (see aileron roll), or to a helical roll in which the nose remains pointed generally along the flight path. In fact, the barrel roll is a specific and difficult maneuver; a combination of a roll and a loop. It is not used in aerobatic competition. From: http://acro.harvard.edu The Barrel Roll is a not competition maneuver. The barrel roll is a combination between a loop and a roll. You complete one loop while completing one roll at the same time. The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot experiences always positive G's. The maximum is about 2.5 to 3 G, the minimum about 0.5 G. |
#22
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Myth: 1 G barrel rolls are impossible.
"mike regish" wrote:
The few that I've done, and it is only a few, the g forces were noticeably less at the top of the roll. I was still pressing into the seat, but not as much. Just as in a loop, the g forces are lower at the top of the loop. That seems reasonable. I should try to clarify that the maneuver I described is what I believe is theoretically possible. |
#23
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Myth: 1 G barrel rolls are impossible.
On 2007-06-11 18:41:50 -0400, "mike regish" said:
The few that I've done, and it is only a few, the g forces were noticeably less at the top of the roll. I was still pressing into the seat, but not as much. Just as in a loop, the g forces are lower at the top of the loop. mike "Jim Logajan" wrote in message .. . Mxsmanic wrote: Jim Logajan writes: Most everyone agrees that keeping the coffee in the cup is possible. What some people don't seem to believe is possible is that the force felt by the pilot (or tea/coffee) can be 1 gee during the entire roll. They believe it has to vary during the roll. I'm hesitant to name names. ;-) It has to vary during the roll, because the constant 1 G acceleration due to gravity does not change. The net acceleration of the aircraft must always be at least one G in consequence, and if the aircraft begins a climb or ends a descent, it _must_ be greater than +1.0 G. Sigh. Yes, the force that is felt is greater then one g-force at the beginning and end of the maneuver. But that is not the case "during the roll" itself. Again, as in the other post of yours I responded to, you appear to be confusing force and acceleration. Easing off the g through the apex is called "the float". You do this because as soon as the lift vector goes below the horizon you pick up 1 extra +g available. In other words, you can easily tighten up the maneuver losing the constant arc of the roll if you don't ease off the g. Same for going over the top in a loop or any maneuver where a constant arc is desired over the top. Since the theoretical objective anyway :-) is to keep the roll arc constant in a barrel roll, you ease off the g through the apex to avoid picking up that extra 1 positive g available and by doing so tightening up the roll arc. So the bottom line is that the positive g does indeed vary through a barrel roll and it is always at some positive g value with the 1 exception being flying through the float with the wings unloaded. I should note that in the true sense of explaining a barrel roll, going to 0 g through the float would be out of the context of a true classic barrel roll which must remain constant throughout the roll. Dudley Henriques |
#24
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Myth: 1 G barrel rolls are impossible.
"Bob Moore" wrote in message 46.128... My name is Bob Moore :-) Just what is a barrel roll has been debated between "Big John", Dudley, and myself at least twice in the past. It IS difficult to describe without having a model airplane in one's hand and flying it through the maneuver. How come you don't seem to belive the following from Wikipedia? Barrel roll From Wikipedia, the free encyclopedia This article is about the aerial sport. For the military operation, see Operation Barrel Roll. A barrel roll occurs when an object (usually an airplane or roller coaster) makes a complete rotation on its longitudinal axis while following a helical path, approximately maintaining its original direction. The G load is kept positive (but not constant) on the aircraft throughout the maneuver, commonly not more than 2-3 G. In aviation, the maneuver includes a constant variation of attitude in all three axes, and at the midpoint (top) of the roll, the aircraft is flying inverted, with the nose pointing at a 90-degree angle ("sideways") to the general path of flight. The term "barrel roll" is frequently used, incorrectly, to refer to any roll by an airplane (see aileron roll), or to a helical roll in which the nose remains pointed generally along the flight path. In fact, the barrel roll is a specific and difficult maneuver; a combination of a roll and a loop. It is not used in aerobatic competition. From: http://acro.harvard.edu The Barrel Roll is a not competition maneuver. The barrel roll is a combination between a loop and a roll. You complete one loop while completing one roll at the same time. The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot experiences always positive G's. The maximum is about 2.5 to 3 G, the minimum about 0.5 G. Then would you label the roll that Jim has described here as a form of aileron roll, instead of a barrel roll? Or do you think it is possible to do a 1g aileron roll? |
#25
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Myth: 1 G barrel rolls are impossible.
Bob Moore wrote:
Jim Logajan wrote Most everyone agrees that keeping the coffee in the cup is possible. What some people don't seem to believe is possible is that the force felt by the pilot (or tea/coffee) can be 1 gee during the entire roll. They believe it has to vary during the roll. I'm hesitant to name names. ;-) My name is Bob Moore :-) Hi Bob. Glad you could make it to B.R.A. (Barrel Rollers Anonymous.) :-) Just what is a barrel roll has been debated between "Big John", Dudley, and myself at least twice in the past. It IS difficult to describe without having a model airplane in one's hand and flying it through the maneuver. How come you don't seem to belive the following from Wikipedia? You know what is odd? The flight path of the maneuver I wrote about appears to violate the Harvard definition you quote (it can't be done in a straight horizontal path - my corkscrew/helical path must follow a parabolic arc) but oddly the Wikipedia definition leaves me a big "out." Straight down. ;-) Drop the nose straight down so as to make the plane & pilot weightless. Then start doing horizontal loops so the centrifugal force yields the equivalent of one gravity of weight. At least the longitudinal axis of the helical path will maintain a constant direction - but the pilot will quickly be screwed. :-) Barrel roll From Wikipedia, the free encyclopedia This article is about the aerial sport. For the military operation, see Operation Barrel Roll. A barrel roll occurs when an object (usually an airplane or roller coaster) makes a complete rotation on its longitudinal axis while following a helical path, approximately maintaining its original direction. The G load is kept positive (but not constant) on the aircraft throughout the maneuver, commonly not more than 2-3 G. In aviation, the maneuver includes a constant variation of attitude in all three axes, and at the midpoint (top) of the roll, the aircraft is flying inverted, with the nose pointing at a 90-degree angle ("sideways") to the general path of flight. The term "barrel roll" is frequently used, incorrectly, to refer to any roll by an airplane (see aileron roll), or to a helical roll in which the nose remains pointed generally along the flight path. In fact, the barrel roll is a specific and difficult maneuver; a combination of a roll and a loop. It is not used in aerobatic competition. From: http://acro.harvard.edu The Barrel Roll is a not competition maneuver. The barrel roll is a combination between a loop and a roll. You complete one loop while completing one roll at the same time. The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot experiences always positive G's. The maximum is about 2.5 to 3 G, the minimum about 0.5 G. |
#26
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Myth: 1 G barrel rolls are impossible.
Mxsmanic wrote in
: Jim Logajan writes: Myth: It is impossible to perform a barrel roll such that the pilot feels exactly 1 gee of force perpendicular to the floor of the cockpit. No maneuver that involves a change in altitude can maintain exactly 1 G along the net acceleration vector (including perpendicular to the cockpit floor). This is not a myth, it's a fact. Shut up fjukkwit. You don't even know why you're right, monkey boi. . Bertei |
#27
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Myth: 1 G barrel rolls are impossible.
Mxsmanic wrote in
: Jim Logajan writes: Most everyone agrees that keeping the coffee in the cup is possible. What some people don't seem to believe is possible is that the force felt by the pilot (or tea/coffee) can be 1 gee during the entire roll. They believe it has to vary during the roll. I'm hesitant to name names. ;-) It has to vary during the roll, because the constant 1 G acceleration due to gravity does not change. The net acceleration of the aircraft must always be at least one G in consequence, and if the aircraft begins a climb or ends a descent, it _must_ be greater than +1.0 G. You're an idiot and you will never ever do a barrel roll. Bertie |
#28
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Myth: 1 G barrel rolls are impossible.
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#29
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Myth: 1 G barrel rolls are impossible.
"No maneuver that involves a change in altitude can maintain exactly 1 G
along the net acceleration vector (including perpendicular to the cockpit floor)." Hey, asshole- how about rolls on the vertical, either up or down? The plane is climbing or descending, while maintaining one g througout. There is no change in the g forces associated with the roll. |
#30
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Myth: 1 G barrel rolls are impossible.
"Maxwell" wrote in
: "Bob Moore" wrote in message 46.128... My name is Bob Moore :-) Just what is a barrel roll has been debated between "Big John", Dudley, and myself at least twice in the past. It IS difficult to describe without having a model airplane in one's hand and flying it through the maneuver. How come you don't seem to belive the following from Wikipedia? Barrel roll From Wikipedia, the free encyclopedia This article is about the aerial sport. For the military operation, see Operation Barrel Roll. A barrel roll occurs when an object (usually an airplane or roller coaster) makes a complete rotation on its longitudinal axis while following a helical path, approximately maintaining its original direction. The G load is kept positive (but not constant) on the aircraft throughout the maneuver, commonly not more than 2-3 G. In aviation, the maneuver includes a constant variation of attitude in all three axes, and at the midpoint (top) of the roll, the aircraft is flying inverted, with the nose pointing at a 90-degree angle ("sideways") to the general path of flight. The term "barrel roll" is frequently used, incorrectly, to refer to any roll by an airplane (see aileron roll), or to a helical roll in which the nose remains pointed generally along the flight path. In fact, the barrel roll is a specific and difficult maneuver; a combination of a roll and a loop. It is not used in aerobatic competition. From: http://acro.harvard.edu The Barrel Roll is a not competition maneuver. The barrel roll is a combination between a loop and a roll. You complete one loop while completing one roll at the same time. The flight path during a barrel roll has the shape of a horizontal cork screw. Imagine a big barrel, with the airplanes wheels rolling along the inside of the barrel in a cork screw path. During a barrel roll, the pilot experiences always positive G's. The maximum is about 2.5 to 3 G, the minimum about 0.5 G. Then would you label the roll that Jim has described here as a form of aileron roll, instead of a barrel roll? Or do you think it is possible to do a 1g aileron roll? It's less of a roll than it is a loop. In fact, that's how I used to teach it. Get a hula hoop, cut it and pull the ends apart. you are now looking at the path of a barrel roll. A skewed loop Bertie |
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