Power Kite Forum

Depower in the air

p8ntballsk8r - 26-10-2009 at 08:43 PM

I'm curious what the effect is of either pulling the bar in more, or pushing the bar outwards when you are in the air. This question is for after you have done a pendulum, jumped and pulled in the bar.

I'm guessing the bar all the way in will give you the float time. Someone please varify that.

Another question is not with the bar but with the powerline? I think that's what it's called. I'm talking about the adjustable pully / line that changes the amount of power the kite is generating.

In a lower wind situation, my assumption is you want it all the way out for max power, because inversely in a very high wind situation, you want it cinched all the way in for minimum power. Are these assumptions correct?

carltb - 27-10-2009 at 01:25 AM

when you jump you pull the bar in to generate power and lift. keep the bar pulled in until you reach the top of the jump, then let the bar out, redirect, then just before touchdown pull in the bar again to soften the landing.

thats the gneral rule but it depends on what you are actually flying

dylanj423 - 27-10-2009 at 05:52 AM

as far as the power line you referenced, that is the "trim strap"... different bars have different systems, so it would be impossible to say without knowing what you are using

Bladerunner - 27-10-2009 at 06:35 AM

It is strange but in low wind you are best off setting your kite to fly hard on the front lines. The kite flies faster that way. Pull in to assist in turning , out to speed through the window.

Depower is a deceptive term.

It is better to think front line and back. Front lines the kite flies faster and farther in to the window. Back is slow and kite falls back in the window.

p8ntballsk8r - 27-10-2009 at 11:29 AM

Thanks carl for clearing most of this up.

Where does Angle of Attack fit into all of this? When you pull in on the bar, my current understanding is you increase the AoA and this is why more lift is produced and you are able to get airborn. Pushing out the bar has the inverse effect of reducing the angle of attack, hence producing less lift and giving you less float and fasting falling to the ground.

As for the Trim Strap, My guess is the same way in that you are changing the AoA of the kite, down to decrease it (since that gives less power) and up to increase the AoA (more power)

Are these assumptions correct?

Carl - it makes sense that you pull in on the bar just before landing again to soften up the landing, but it seems as though you would want to keep the bar all the way in to float down as gently as possible from your highest point in the air.

One last question, is it possible when increasing the AoA to do so too far, to the critical angle of attack, and to stall the kite while you are in the air putting weight on it?

If it matters, I'm flying an Ozone Frenzy

dylanj423 - 27-10-2009 at 12:09 PM

dont worry about the angle of attack too much, it is a very scientific and technical explanation that required clarification by an aviation student for me, and the effect of the AOA depends on the profile of the kite, and how some other factors come into play... more info than you really need...

worry about leading edge and trailing edge... when you pull the bar in, it pulls the lines on the trailing edge, this gives you the pop into the air (lift)... again, up and down in respect to the trip strap depend on which trim strap you are using... for some, down is powered up, and some up is powered up,...

when the trim is all the way OUT, the kite is catching more power (this can be UP, or DOWN, depending on which system in use)... when the trim is all the way IN, most of the power is going to the power lines that go to the leading edge, this is the least powerful setting (and also can be UP or DOWN, depending on which system you are using)

using the words IN, OUT, LEADING EDGE, TRAILING EDGE are universal, each bar has its own system, and we dont want to give you the wrong answers and have you act on our info wrongly, that can hurt you...

carltb - 27-10-2009 at 12:10 PM

looks like you have the aoa sorted.

the reason why you let the bar out at the top of the jump is firstly to stop the kite from stallng and secondly, it flys faster so makes the redirect easier.

p8ntballsk8r - 27-10-2009 at 09:03 PM

I actually am an aviation student. Air Traffic Control, but I got my pilots liscense last year, so I understand AoA just fine.

In general, do lower winds not allow the kite to move as fast? I had some trouble today static jumping in winds that weren't really strong enough to jump in. When I could get enough pull to get airborn with some hangtime, I didn't have enough to get the redirect back, and my landings were harder than they should have been. I do have a bigger kite - 12m so this could be in part, but I'm guessing it was also due to the low winds which where between 12 and 14 kts.

There were actually a few times where I had to run backwards to get the kite's airspeed up when the corners started to tuck and the kite began not to respond

Bladerunner - 28-10-2009 at 06:38 AM

OOPS ! Coffee , need COFFEE!!!

Maven454 - 28-10-2009 at 06:42 AM

Quote:
Originally posted by Bladerunner
Thank you for clearing this up.

I feel that Jonesband 1998 will be even more frustrated when he finds he has been nothing but entertainment to us. His actions will have NO effect on this forum or the people who use it.

The people on this site are savey shoppers or beginers who have found the right place for advice. The good advice and gear will still freely flow !

Poor Jonesy is spinning wheels :yes:


Pretty sure you got this on the wrong thread Bladerunner.

Maven454 - 28-10-2009 at 06:55 AM

Quote:
Originally posted by Bladerunner
OOPS ! Coffee , need COFFEE!!!

:lol::lol:

You've got to stop posting first thing in the morning...

ragden - 28-10-2009 at 07:17 AM

:lol:

acampbell - 28-10-2009 at 11:01 AM

Quote:
Originally posted by p8ntballsk8r
Thanks carl for clearing most of this up.

As for the Trim Strap, My guess is the same way in that you are changing the AoA of the kite, down to decrease it (since that gives less power) and up to increase the AoA (more power)

Are these assumptions correct?


One last question, is it possible when increasing the AoA to do so too far, to the critical angle of attack, and to stall the kite while you are in the air putting weight on it?

If it matters, I'm flying an Ozone Frenzy


I like to think of the center trim strap as the transmission and the bar as the throttle. Have the kite in the wrong gear and hit the gas and you will stall the kite.

In light wind, flying statically, the de-power kite will likely behave "bass-ackwards". Pull the bar in to "create more power" and all you do is kill (stall) the kite. Then, almost counter intuitively, you let the bar all the way out and trim strap in for "max-depower" and the kite is able to recover from the stall, begin flying, pick up speed and actually create power.:puzzled: :puzzled:

Now once you put the rig into motion on a board, skis or in a buggy, then all is right with the world as the rig feels the apparent wind and works as advertised.

In the buggy on a beam reach park-and-ride, I like to set my center strap (gear shift) such that right when the bar gives enough resistance to the pressure of a few fingers is when the back wheels break loose. Then the bar, from all the way out to that point pulling in, is acting as my throttle for buggy speed.