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 Post subject: Gliding vs jumping.
PostPosted: Wed Dec 26, 2012 8:05 am 
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Lets hear the interpretations.. The perceived differences.

Gliding vs jumping

My take:
Gliding:
Jumping off a hill. Landing in a very different location tyically upwind. Spending typically more then 8-45 seconds in the air

Jumping:
Jumping in or on flat ground or rolling hill. Landing in an area close to take off and landing downwind. Usually less then 15 seconds in the air.

Any other thoughts.


Last edited by crabnebula on Mon Dec 31, 2012 3:49 am, edited 2 times in total.

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 Post subject: Re: Gliding vs jumping.
PostPosted: Fri Dec 28, 2012 7:22 am 
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I am glad that you brought up this topic. I think most of us are familiar with jumping, so I will mention the differences.

Gliding consists of gaining enough ground speed to produce flight. A glide can be as short as a small jump to minutes of airtime. A glide does not require the kite to be redirected nor does it require line tensioning or progressive edging to produce flight. it is more akin to paragliding while jumping is similar to jumping on a wakeboard.

A typical glide consists of first climbing a hill. Turning so that you are facing downhill and flying the kite near zenith (11 or 1 if 12 o'clock is zenith), sheeting out the bar and bombing down the hill. When the kiter feels lift, sheet-in the bar and flight begins. Some kiters fly forwards, some backwards. If you fly forwards, you have to remember that the inputs are opposite to what your intuition would tell you. During a glide a rider may steer the kite back and forth, this places the kite a little deeper in the wind window causing additional lift. Landing can be done gracefully by redirecting the kite or with a kite loop.

A glide is even more susceptible to the elevator effect due to the nature of a hill (the wind flows upward). If you watch the video in "Elevator Day" at Skyline it will give you a good idea of what can happen.

Kenny


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 Post subject: Re: Gliding vs jumping.
PostPosted: Fri Dec 28, 2012 8:15 am 
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Nice try but your gliding theories are wrong.

Gliding starts when there is enough AIR speed. Combine that with angle of attack to produce required lift. Sheeting in means you are increasing the angle of attack to have more lift from airfoil.

When airborne there is no wind window. There is head wind and tail wind depending trajectory you are flying. Wind is visible to flyer as ground speed. Then there is wind upward component caused by the shape of ground. Wind turned upwards can go really high as glider planes prove that (and 'wave' clouds).

Then there is sink rate, wing loading, g force... Don't kill yourself.

On the movie Speed3 kicks some ... :)


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 Post subject: Re: Gliding vs jumping.
PostPosted: Fri Dec 28, 2012 3:01 pm 
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How big was that speed 3?


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 Post subject: Re: Gliding vs jumping.
PostPosted: Fri Dec 28, 2012 5:17 pm 
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When jumping, the kite does not really gain airspeed (speed relative to the surrounding air mass).

When gliding, the kite has generated airspeed. Whether you are gliding into the wind, cross, or even downwind, your kite is moving forward through the airmass at the same speed. The only significant changes will be in regard to your groundspeed.

Have fun!
Matt D


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 Post subject: Re: Gliding vs jumping.
PostPosted: Fri Dec 28, 2012 8:31 pm 
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jakemoore wrote:
How big was that speed 3?


By looking at the coloring it was 21m CE


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 Post subject: Re: Gliding vs jumping.
PostPosted: Sat Dec 29, 2012 2:50 am 
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Quote:
Nice try but your gliding theories are wrong.

Gliding starts when there is enough AIR speed. Combine that with angle of attack to produce required lift. Sheeting in means you are increasing the angle of attack to have more lift from airfoil.


Joriws,

You are correct. The kite develops AIR speed to produce lift. However, if the kiter does not produce some ground speed, the AIR speed doesn't happen (unless you fly off a cliff).

Yes, the kite in the video is a 21m Speed 3. It is basically a paraglider on long lines and the lift is incredible.


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 Post subject: Re: Gliding vs jumping.
PostPosted: Sat Dec 29, 2012 1:17 pm 
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fernmanus wrote:
You are correct. The kite develops AIR speed to produce lift. However, if the kiter does not produce some ground speed, the AIR speed doesn't happen (unless you fly off a cliff).


This is mostly true. But air/ground speed is always relative. Even 747 could lift off stationary (ground speed 0knots/mph/kmph) if there is hurricane speed winds giving enough air speed to wings/fuselage. But 747 needs engine power to counter the sink rate and maintaining air speed while airborne. Or to maintain/increase energy.

On a strong head wind kiter can get airborne while stationary and with upward wind component. On the edge the hill with a hang glider gently push bar away (increase aoa) and you lift off while standing. I've flown/landed backwards (negative ground speed) with a hang glider in a strong head wind. So gliding is all about air speed IMO. Too low air speed and you stall. But ground speed does not matter. While airborne the gps always shows ground speed.


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 Post subject: Re: Gliding vs jumping.
PostPosted: Sun Dec 30, 2012 1:30 am 
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Location: jackson WY
Have you ever stalled a kite while in the air? Almost impossible!


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