Don't mean diablo : "0:-20" not "12:-20". I think you should use the terms + for things that are closer to the kite.Regis-de-giens wrote:Normally the philosophy of standard SS is to keep a constant camber (can be a bit different depending on bridle location on each kite, but that is the "average" philosophy ) ; so assuming that Standard SS leads to almost constant camber, now if we compare to Standard SS (we deduce each values with the Standard SS) we get :
- standard : 0:0:0:0 (normal , this is the reference)
- WAC : "0:-2:-3:0"
- diablo : "12:-20"
I think you are making some assumptions about what is the best profile. Some CFD would be needed to tell us that but I will give you the basics. From the point of highest or best L/D, you want flat or a bit of negative camber. For most lift you want as much curve as you are going to get or high camber, so in that regard WAC is superior to Diablo line because B is held longer/looser. The problem with a standard mixer is if it is set for a flat profile it can not transition to a high camber(without stalling) and if it is set for high camber it can not achieve a flat profile. There is distinct advantages to each profile and the addition of either of these mods allows them to be accessed but differently. The main advantage to a flat profile is to be lightly powered and fast flying, it allows efficient flight. This would be when you are riding and going fast or sineing the kite to go upwind. The main advantage of higher camber is when the flight speed is low and lift is hard to generate, like trying to get up on the board or landing a jump or heading downwind. It also has the curious effect of lowering the stall speed, which allows the kite to fly in even less wind. The exact shape of the camber is perhaps not so important for this lift at low speeds, but for relaunch maybe. The camber shape of the WAC relaunches much better than the standard mixer and of course diablo line which is worse.Regis-de-giens wrote: In term of camber, this means that for a 12cm stroke on Z, both SS have more camber with:
- Wac : C=-2cm ; B=-3cm which is not very homogenous in term of profile efficiency (at least L/D ratio, but once again that may not be your objective)
- Diablo : C=-2cm ; B=-1cm which is more homogenous in term of profile efficiency and often used to get more lift on a foil kite(*)
The engagement point should be set for when you want the profile to change. Interestingly this is good at all even ABCZ on flysurfers. The all even point is also where flysurfer recommends sheeting the bar in should stop to prevent backstall. I had been wondering how flysurfer set this point, I guess it must probably be in relation to stall. So in that regard you could notice at what point the bar sheeted in stalls the kite, or for any other point for that matter, and from there you could work out the mixer state at that bar point and set the WAC/diablo line to engage at or before it. Some where near the stall point is actually I think a good place for these to engage as it lowers the stall, further extending the bar throw before stall.Regis-de-giens wrote: When changing cambers to optimize the foilkite for certain wind conditions or practice, it is common to change B and C in the range of 2-4 cm but not far more; hence I would bet that to keep the kite flying well when fully sheeted-in, you need to engage the diablo line in the last 20-25 cm of your bar stroke (pure theoetical guess to be confirmed, the sooner you engage the line, the more it will change the behavior of course).
This is COMPLETELY incorrect. I tell you from experience they are much the same but maybe WAC is lighter. WAC exposes B pulley to the load of A. Only 1/4 of the force on B makes it to the bar. There is of course the increased force on B ,C and particularly Z as the COL(center of lift) moves back and increase far beyond what the standard mixer can muster. This is of course the exact problem the diablo line will have but in a way worse. I will say quickly, a kite like the A15 is uniquely able to handle these forces better as the supported area between A and B is much wider and so cover much more COL change, C is also further back , and because it carries force to the bar at 1/2 offers even more protection. Z is of course 1 to 1.Regis-de-giens wrote:Lastly, regarding bar pressure : WAC should lead to almost +100% of bar pressure ; Diablo should lead to a very light bar pressure increase of 5-10%. Keep also in mind that for a similar bar stroke, WAC has -25 % less efficiency on AoA while Diablo is 50 % more efficient (hence twice more efficient than WAC on AoA change).
I think WAC has a better profile and tighter turn, but turning is not so important for racing and also their bars have plenty of trim to tolerate WAC.Regis-de-giens wrote:In a nutshell, I would then conclude:
- chosing the diablo for race, turning ability and depower on shorter stroke, with a good boosting power with homogenous profile when sheeting-in; bar pressure is a bit higher.
- choosing the WAC for kites that have a B briddle connection line near the middle of the kite like A15, or if main objective is to increase much the bar pressure (Flysurfer uses this WAC line for this purpose mainly); but the kite could be less stable and less rapid in the window when sheeted-in.
holden wrote:he tested diablo 10 and 15, joker6 9 and 11 and chrono2 15 which he modified himself.
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