TAS
308 posts
Yeah steve's comment had me double checking the demo's bar, didn't think it felt like a big bar!
Does anyone have any info on how back line tension affects lower end grunt? ie. if you fly C-kites with tighter back lines does it equal more pull (to a point?).
WA
2782 posts
Hi Funkyllama,
By adding tension or shortening the back lines, you effectively increase angle of attack of the wing when sheeted in to full power. Problem with this is, if you already have full power before shortening the back lines with trimmers or knots, then you are going to start oversheeting. Over sheeting leads to stalling the wing by moving the separation point forward, up to the lift producing curve of the airfoil.
The separation point is usually at or around about the trailing edge when everything is normal. A separation point is where the laminar flow of air separates away from the wings upper skin due to too higher an angle of attack. The higher the angle of attack, the further forward the separation point moves. Behind the separation point is turbulence which kills off lift created by high speed laminar flow of air over the wing chord.
The C4's and also Catalysts are quite resistant to over sheeting and subsequently stalling. This is great for general users but unless you know what's going on, you can be over sheeting for no real advantage.
Useless versheeting is where the bar is pulled in slowly and you notice a continuous increase in power to a point where no matter how much further you pull the bar,power does not increase. This is over sheeting. Over sheeting is pointless due to the lack of additional power, but where it really hurts you, is the de-power that you are chewing up.
If you lengthen the back lines so that the kite is trimmed perfectly for maximum power when the bar is pulled in to the stopper at around the chicken loop, then instead of using up essential de-power line length for no advantage, you can gain depower from sheeting all the way out along the de-power line.
Put another way, if you have 20 inches of de-power to go from full power to full de-power, and the distance the bar travels is 20 inches, then the bar is perfectly matched to the kite and will give you full range of kite power.
If you have 4 inches of over sheeting through the trimmers being tight, then you have robbed 4 inches from the de-power and have 4 inches of useless travel where you are going past the point of maximum power and are over sheeting and not gaining anything.
On any kite, it is worth while testing to see if your kite is oversheeting.
Hope this makes sense.
KH
TAS
308 posts
Good post Kitehard. Nailed explaining how depower works.
Had noticed that the GK Sonics that I used to fly really liked having looser backlines to fly (and had a light bar pressure) or you found out all about backstalling, and also noticed that the C4 had light bar pressure too but no way could i get it to back stall. Made me wonder if putting more tension on the back lines on the C4 would give a greater bottom end, and if that was a characteristic of C kites.
Generally found that after flying kites that are sensitive to backstalling, and fiddling with bridles and trim etc to get unhooking right, its just plain wicked moving to something like the C4 where it just doesn't seem to care about being oversheeted. A very low maintenance kite!!!
