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#1
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Slipping in Turns
I'm wondering if many people hold a mild slip in turns and why they do it.
Please reply to this post if you do this and give your reason(s). Thanks, Jim Hendrix |
#2
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I'm wondering if many people hold a mild slip in turns and why they do it.
Please reply to this post if you do this and give your reason(s). Thanks, Jim Hendrix I do because Dick Johnson, in a talk, convinced me it is both safer and more aerodynamically efficient. It also seems to make it easier to thermal precisely. Larry Pardue 2I |
#3
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Jim Hendrix wrote:
I'm wondering if many people hold a mild slip in turns and why they do it. Please reply to this post if you do this and give your reason(s). Thanks, Jim Hendrix Yes many do, me included. In the gliders I've tried it in, Grob 103 Ventus b and Mosquito, I find I have much better pitch control when turning steeply e.g. 45 deg. People argue the aerodynamic pros and cons. I figure if I can stay in a tight thermal more easily, or a more powerful core, I'll climb faster. Works for me. Cheers, Shawn |
#4
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Jim,
There was a thread on this subject a year or two ago, you might want to search the archives. The simple aerodynamic answer goes like this: The circle is traced by the glider's center of gravity, which means that your nose extends beyond the edge of the circle. To visualize, draw a circle, then draw a line tangent to it. You can see that the nose and tail of your fuselage transcribe larger circles. A yaw string forward of the cg will show a slight slip for a coordinated turn (that is, coordinated at the cg, or wing). If your yaw string is straight, then you are, in fact, slightly skidding the turn. This effect also exists at the tail, requiring you to hold a little bit of rudder into the turn (but not so much that you straighten out the yaw string). Obviously, the longer the arm, the greater the effect. I've tried to observe the difference between the front and rear yaw strings on a G103, but the canopy edge generates too much turbulence to mark any clear difference. For practical purposes, the slip is small (5 to 10 degrees). |
#5
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Measured with a cad-program, for a turn radius of 30 m, the thread angle
should be 3.6 degrees, if the distance of the thread from cg is 2 m. Tighter turn, wider angle. How precisely you can keep your thread in a 3-4 degree angle? js "Chris OCallaghan" wrote in message om... Jim, There was a thread on this subject a year or two ago, you might want to search the archives. The simple aerodynamic answer goes like this: The circle is traced by the glider's center of gravity, which means that your nose extends beyond the edge of the circle. To visualize, draw a circle, then draw a line tangent to it. You can see that the nose and tail of your fuselage transcribe larger circles. A yaw string forward of the cg will show a slight slip for a coordinated turn (that is, coordinated at the cg, or wing). If your yaw string is straight, then you are, in fact, slightly skidding the turn. This effect also exists at the tail, requiring you to hold a little bit of rudder into the turn (but not so much that you straighten out the yaw string). Obviously, the longer the arm, the greater the effect. I've tried to observe the difference between the front and rear yaw strings on a G103, but the canopy edge generates too much turbulence to mark any clear difference. For practical purposes, the slip is small (5 to 10 degrees). |
#6
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I'm anyway too stupid to fly coordinated, so I choose to better slip into
the thermal than skidding out of it :-) -- Bert Willing ASW20 "TW" "Shawn Curry" a écrit dans le message de hlink.net... Jim Hendrix wrote: I'm wondering if many people hold a mild slip in turns and why they do it. Please reply to this post if you do this and give your reason(s). Thanks, Jim Hendrix Yes many do, me included. In the gliders I've tried it in, Grob 103 Ventus b and Mosquito, I find I have much better pitch control when turning steeply e.g. 45 deg. People argue the aerodynamic pros and cons. I figure if I can stay in a tight thermal more easily, or a more powerful core, I'll climb faster. Works for me. Cheers, Shawn |
#7
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What about this: when I press another pedal slowly down an keep it there,
holding wings level, plane begins to fly round a point at the noses and pressed pedals side. Thread shows I am skidding to opposite side. I could allmost thermal like this, holding wings in level. So why shoud I slip into thermal, becouse skidding out of it turns the plane into the direction of thermals core. Complicated... js "Bert Willing" wrote in message ... I'm anyway too stupid to fly coordinated, so I choose to better slip into the thermal than skidding out of it :-) -- Bert Willing |
#8
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Because the turn you are creating by banking into the
thermal is soooooooo much bigger than the tiny turning effect of the slip and, as has been said before, you are slipping towards the centre of the thermal, which has to be good. (Actually, you are slipping towards a point that is always a little in front of the core, but -hey- I can't fly that accurately either!) Rob At 10:42 26 November 2003, Js wrote: What about this: when I press another pedal slowly down an keep it there, holding wings level, plane begins to fly round a point at the noses and pressed pedals side. Thread shows I am skidding to opposite side. I could allmost thermal like this, holding wings in level. So why shoud I slip into thermal, becouse skidding out of it turns the plane into the direction of thermals core. Complicated... js 'Bert Willing' wrote in message ... I'm anyway too stupid to fly coordinated, so I choose to better slip into the thermal than skidding out of it :-) -- Bert Willing |
#9
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I see it all the time in the L-23. The string in front
shows a slight slip while the one for the back seat shows a coordinated turn. At 23:42 25 November 2003, Chris Ocallaghan wrote: Jim, There was a thread on this subject a year or two ago, you might want to search the archives. The simple aerodynamic answer goes like this: The circle is traced by the glider's center of gravity, which means that your nose extends beyond the edge of the circle. To visualize, draw a circle, then draw a line tangent to it. You can see that the nose and tail of your fuselage transcribe larger circles. A yaw string forward of the cg will show a slight slip for a coordinated turn (that is, coordinated at the cg, or wing). If your yaw string is straight, then you are, in fact, slightly skidding the turn. This effect also exists at the tail, requiring you to hold a little bit of rudder into the turn (but not so much that you straighten out the yaw string). Obviously, the longer the arm, the greater the effect. I've tried to observe the difference between the front and rear yaw strings on a G103, but the canopy edge generates too much turbulence to mark any clear difference. For practical purposes, the slip is small (5 to 10 degrees). |
#10
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"JS" wrote in message ...
Measured with a cad-program, for a turn radius of 30 m, the thread angle should be 3.6 degrees, if the distance of the thread from cg is 2 m. Tighter turn, wider angle. How precisely you can keep your thread in a 3-4 degree angle? js Hello JS -You must be flying a hang glider to be capable of turning a 30 meter radius while thermalling. For a given bank angle, the theoretical turn radius is proportional to the square of the flight velocity. Right? My unballasted Ventus requires about 48 kts of airspeed when performing a 45 degree banked thermalling turn. Under those conditions I calculate my turn radius to be about 204 ft, or 62 meters. Dick Johnson |
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