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#101
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barrel roll in 172
"Big John" wrote in message ... Dudley Can it be said? In a Barrel Roll the ball starts centered and stays centered throughout the roll until aircraft returns to straight and level flight and starts some other maneuver. If you are good, you can fly a barrel roll center ball. This requires a near perfect blend of all controls and is the right way to do the classic BR. In a Slow Roll (sometimes called Point Roll) the ball starts centered and is then never centered except momentarily when bird has rolled 180 degrees and is inverted, until completion of roll and return to straight and level flight? Well...almost :-) You might lose the center ball as you pull to the roll set point but in theory it should remain more of less centered up till roll initiation. Immediately after you initiate a slow roll, you will lose a center ball as all control input through a slow roll is done in a constantly changing cross control dynamic. In theory, you should have a doghouse ball passing through the exact inverted point, but what actually is happening at this point is that you will be changing rudder to regain top rudder on the back side, so the airplane will be in a state of transition even through exact inverted. Personally, I never used a ball at all in aerobatics and I don't recommend using a ball to other aerobatic instructors. One of the benefits involved in learning to fly acro is that you learn to judge maneuver quality with your eyeballs on the nose attitude outside the airplane . All positioning is eyeball related and any unwanted yaw should be immediately apparent by watching the nose. I discourage ball use even in primary students, and get their heads outside where it belongs as soon as possible. All pilots should learn as soon as possible to judge turn quality from nose attitude behavior. I know many...many aerobatic pilots who take the ball out of their airplanes simply to save the weight and space the instrument takes up on the panel. Rolls are easy to explain face to face in briefing using hands or models and demo in air, but over Internet the nuances of English make it difficult. This can be quite true. Dudley Henriques Big John `````````````````````````````````````````````````` ````````` On Fri, 21 Jul 2006 14:43:10 GMT, "Dudley Henriques" wrote: Ron; I think what might be happening here is that some folks are defining the roll from the set point rather than from level flight. It's true that any raising of the nose from level flight will require more than 1 g, but once at the set point and initiating the roll (aileron roll) you can unload the airplane all the way down to 0 g if you like right up to the backside recovery to level flight, where the g of course has to be returned. Dudley Henriques "Ron Natalie" wrote in message . com... Big John wrote: Andrey As has been said in all the posts, the short answer is NO. 172 is not certified to do barrel rolls. However I can barrel roll a 172 only pulling 1 G which puts no more load on airframe than straight and level flight. I have thousands of hours to back up my statement. No you can not. It's not possible to even start the roll without going greater than 1G. |
#102
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barrel roll in 172
"Jim Macklin" wrote Already went looking and found it. As Shake Spear said, a pig pen smells just like a sty. Or was it roses? So, are you saying you don't think much of the site, or what? What is wrong with it? -- Jim in NC |
#103
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barrel roll in 172
No, great site, I was [should have been more clear] speaking
to the use of the terms for types of rolls. BTW, I've been an EAA Lifer a very long, long time. "Morgans" wrote in message ... | | "Jim Macklin" wrote | | Already went looking and found it. As Shake Spear said, a | pig pen smells just like a sty. Or was it roses? | | So, are you saying you don't think much of the site, or what? What is wrong | with it? | -- | Jim in NC | |
#104
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barrel roll in 172
On Sat, 22 Jul 2006 11:35:27 -0500, Big John
wrote in :: Flight load factor Flaps up = +4.4 G's and -1.76 G's So, in inverted flight a C-172 has only a 76% of a G margin to carry additional G force. That isn't much. Thanks. |
#105
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barrel roll in 172
On Fri, 21 Jul 2006 23:10:46 GMT, "Dudley Henriques"
wrote: "Big John" wrote in message .. . Dudley Can it be said? In a Barrel Roll the ball starts centered and stays centered throughout the roll until aircraft returns to straight and level flight and starts some other maneuver. If you are good, you can fly a barrel roll center ball. This requires a near perfect blend of all controls and is the right way to do the classic BR. In a Slow Roll (sometimes called Point Roll) the ball starts centered and is then never centered except momentarily when bird has rolled 180 degrees and is inverted, until completion of roll and return to straight and level flight? Well...almost :-) You might lose the center ball as you pull to the roll set point but in theory it should remain more of less centered up till roll initiation. Immediately after you initiate a slow roll, you will lose a center ball as all control input through a slow roll is done in a constantly changing cross control dynamic. In theory, you should have a doghouse ball passing through the exact inverted point, but what actually is happening at this point is that you will be changing rudder to regain top rudder on the back side, so the airplane will be in a state of transition even through exact inverted. Personally, I never used a ball at all in aerobatics and I don't recommend using a ball to other aerobatic instructors. One of the benefits involved in learning to fly acro is that you learn to judge maneuver quality with your eyeballs on the nose attitude outside the airplane . All positioning is eyeball related and any unwanted yaw should be immediately apparent by watching the nose. I discourage ball use even in primary students, and get their heads outside where it belongs as soon as possible. All pilots should learn as soon as possible to judge turn quality from nose attitude behavior. I know many...many aerobatic pilots who take the ball out of their airplanes simply to save the weight and space the instrument takes up on the panel. Rolls are easy to explain face to face in briefing using hands or models and demo in air, but over Internet the nuances of English make it difficult. This can be quite true. Dudley Henriques Big John `````````````````````````````````````````````````` ````````` On Fri, 21 Jul 2006 14:43:10 GMT, "Dudley Henriques" wrote: Ron; I think what might be happening here is that some folks are defining the roll from the set point rather than from level flight. It's true that any raising of the nose from level flight will require more than 1 g, but once at the set point and initiating the roll (aileron roll) you can unload the airplane all the way down to 0 g if you like right up to the backside recovery to level flight, where the g of course has to be returned. Dudley Henriques "Ron Natalie" wrote in message .com... Big John wrote: Andrey As has been said in all the posts, the short answer is NO. 172 is not certified to do barrel rolls. However I can barrel roll a 172 only pulling 1 G which puts no more load on airframe than straight and level flight. I have thousands of hours to back up my statement. No you can not. It's not possible to even start the roll without going greater than 1G. Preface: I'm an IAC member and have been flying competitions since '95 in Yaks, Sukhois and Extras and also in unlimited gliders. I have also held an FAA form 8710-7 card for air shows. (not current) This morning I went out to play with some barrel rolls in the Extra 300. I'd like to offer that no one has yet mentioned that you can fly very different sorts of barrel rolls where the main variable is the amount the nose deflects from level flight. I think the "fighter pilot" sort of barrel roll that is done to avoid overshooting an opponent or to cause a following opponent to overshoot you is typically done with not so much upward and downward nose deflection from level. If you start an aileron roll and add in just a touch of back stick at the beginning and end with a bit of push while inverted, you'll fly a very tight barrel roll with minimal nose deflection. On the other hand, if you use a lot of nose deflection so that the nose goes all the way to vertical, you make a very different looking barrel roll. THIS is the barrel roll that you can say is a combination of a roll and a loop. People are claiming 1 g barrel rolls can be performed. Nope. Not if you are starting and ending in level flight. On a ballistic trajectory, maybe. This is especially true for the big barrel roll which can be said to be a combined roll and loop. A round loop requires at least 3.5 - 4 g. I usually use around 6 g at the beginning and end of my loops to make them look nice and round. To get a similar barrel roll requires similar g levels. It has been said in this thread that "there is no competition barrel roll". That is about half true. There used to be (long before I got into it) a competition barrel roll but it was deleted from the catalog. The current catalog of figures has a pair of figures called "quarter clovers". Each of these consist of half a barrel roll and half of a loop. In one, as you pull into a loop, you put in some aileron. You continue with the rolling until you reach the top of the loop. At this point, you are inverted, level and have turned the nose 90 degrees from the original flight direction. You then center the ailerons and fly the bottom half of a loop back to straight and level. The other quarter clover is done in the opposite manner, i.e., the first half of the figure is a half loop with no rolling. The second half of the figure combines aileron input with elevator to return to straight and level upright flight but with a 90 degree heading change from the original direction of flight. I think these are called quarter clovers because if you did four of them in succession with the smoke on, (and no wind) you'd make a nice 4-leaf clover figure in the sky. If you performed the first half of the first quarter clover and the second half from the second quarter clover, with the same aileron deflection on both halves, you'd fly the classic really big barrel roll. These figures were first used for aerobatic glider competitions and then were also recently used in the Sportsman "known" sequence. I've never seen them flown at higher levels of competition. Many times, competitors are downgraded for "barreling" a "slow" roll. Note that the word slow means nothing for the speed of rolling. In a slow roll the fuselage does not deflect during the roll. An aileron roll is one where you begin with a pull to get some nose up deflection, followed by a return to 1 g (or less) and the aileron deflection to roll about the longitudinal axis. After return to wings level, the nose may have dropped below horizontal and will need a little pull to return to level. A fast rolling airplane (like a Sukhoi or Extra) can complete the roll so quickly that the aileron roll and slow roll look the same and are performed the same. A barreled roll would have discernable nose deflection during the course of the roll. Most competitors have this happen to them on the last half of a full roll. This defect is also called "dished". I think it usually happens because the pilot uses inadequate push while inverted, allowing the nose to drop from the horizontal. If doing it at low level, you can find yourself at zero altitude (or less), as Dudley has pointed out. :-( In unlimited glider aerobatic competitions there is a figure called the "super slow roll" where a 360 degree roll must take AT LEAST 10 seconds to perform. The chief judge times you and if you do it too fast, you "zero" the figure. Or course, there is lots of opportunity for every little defect in technique to become obvious to the judges. A "point" roll is one where the rolling is stopped briefly and restarted one or more times - also sometimes called a "hesitation roll". E.g., a four point roll would consist of 4 - 90 degree rolls in the same direction with a brief pause between each of the 90 degree rolls for a total of 360 degrees of rolling to get back to the starting attitude. I agree with the point made about using the ball during acro. I never look at mine and my aerobatic glider doesn't even have one. Doesn't have a yaw string either. :-0 I don't need it. Happy landings, Klein |
#106
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barrel roll in 172
"Klein" wrote in message ... On Fri, 21 Jul 2006 23:10:46 GMT, "Dudley Henriques" wrote: In unlimited glider aerobatic competitions there is a figure called the "super slow roll" where a 360 degree roll must take AT LEAST 10 seconds to perform. I love the super slow roll, and consider it one of the harder maneuvers to perform correctly in demonstration work. I once did one in an S1S Pitts the entire length of Dulles Airport. Takes tremendous timing and coordination in the Pitts. I used my fingertips on the stick and braced my heels solidly on the floor using my ankles as fulcrums on the rudder for this maneuver; (which I always did anyway :-) . Dudley Henriques |
#107
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barrel roll in 172
Larry Dighera wrote:
On Sat, 22 Jul 2006 11:35:27 -0500, Big John wrote in :: Flight load factor Flaps up = +4.4 G's and -1.76 G's So, in inverted flight a C-172 has only a 76% of a G margin to carry additional G force. That isn't much. Thanks. No, 176% of a G. Matt |
#108
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barrel roll in 172
On Sun, 23 Jul 2006 01:54:35 GMT, Matt Whiting
wrote in :: Flight load factor Flaps up = +4.4 G's and -1.76 G's So, in inverted flight a C-172 has only a 76% of a G margin to carry additional G force. That isn't much. Thanks. No, 176% of a G. No. A _margin_ of only a 76% of a G to carry G forces in addition to the one G natural force. |
#109
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barrel roll in 172
Larry Dighera wrote:
On Sun, 23 Jul 2006 01:54:35 GMT, Matt Whiting wrote in :: Flight load factor Flaps up = +4.4 G's and -1.76 G's So, in inverted flight a C-172 has only a 76% of a G margin to carry additional G force. That isn't much. Thanks. No, 176% of a G. No. A _margin_ of only a 76% of a G to carry G forces in addition to the one G natural force. When you are pulling negative G, there is no one natural G force. It takes -1 G of acceleration to counter gravity and get you to 0 G. You can then add -1.76 G of additional acceleration and still be within load limits. The negative G load factor is referenced to 0 G, not 1 G straight and level. Matt |
#110
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barrel roll in 172
In article ,
Matt Whiting wrote: When you are pulling negative G, there is no one natural G force. It takes -1 G of acceleration to counter gravity and get you to 0 G. You can then add -1.76 G of additional acceleration and still be within load limits. The negative G load factor is referenced to 0 G, not 1 G straight and level. Is negative G an up force or a down force? |
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