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Re: The Firefly V2 mod

Posted: Mon Jul 27, 2020 1:33 am
by Adventure Logs
Janus wrote:
Thu Jul 23, 2020 10:05 pm
Oh I forgot about the flapping... just a tiny bit bar pressure and it’s gone.. when even that is too much.. rig smaller.
This is how I cut back the flapping as well. Just keep a little pressure on the bar and it really helps. Works really well in overpowered condition too. Prevents the kite from deforming as much.

Re: The Firefly V2 mod

Posted: Mon Jul 27, 2020 9:21 am
by kitexpert
Adventure Logs wrote:
Mon Jul 27, 2020 1:33 am
Janus wrote:
Thu Jul 23, 2020 10:05 pm
Oh I forgot about the flapping... just a tiny bit bar pressure and it’s gone.. when even that is too much.. rig smaller.
This is how I cut back the flapping as well. Just keep a little pressure on the bar and it really helps. Works really well in overpowered condition too. Prevents the kite from deforming as much.
For sure sheeting bar in helps against flutter but you can't get around it that then some depower is lost. If you always want to sheet in a bit it means you don't agree with the designer how kite should work or how it should be adjusted. In your opinion there is unusable depower in the kite.

Adding more lines to keep kite less fluttering is a bit same. First of all it adds a bit complexity, drag and weight, but these don't matter so much because all of that is already plenty. Bigger question is that when flutter is worst kite is depowered and added lines to the back (C-D) should be pretty or complete loose. Adding loose lines doesn't make that much sense and if they are not loose depower is compromised.

Re: The Firefly V2 mod

Posted: Mon Jul 27, 2020 8:54 pm
by br44
kitexpert wrote:
Mon Jul 27, 2020 9:21 am
Adventure Logs wrote:
Mon Jul 27, 2020 1:33 am
Janus wrote:
Thu Jul 23, 2020 10:05 pm
Oh I forgot about the flapping... just a tiny bit bar pressure and it’s gone.. when even that is too much.. rig smaller.
This is how I cut back the flapping as well. Just keep a little pressure on the bar and it really helps. Works really well in overpowered condition too. Prevents the kite from deforming as much.
For sure sheeting bar in helps against flutter but you can't get around it that then some depower is lost. If you always want to sheet in a bit it means you don't agree with the designer how kite should work or how it should be adjusted. In your opinion there is unusable depower in the kite.

Adding more lines to keep kite less fluttering is a bit same. First of all it adds a bit complexity, drag and weight, but these don't matter so much because all of that is already plenty. Bigger question is that when flutter is worst kite is depowered and added lines to the back (C-D) should be pretty or complete loose. Adding loose lines doesn't make that much sense and if they are not loose depower is compromised.
If you look at a beach sheet flapping in the wind, you can see irregular sinusoid waves in the material — above and below. Thus it appears that those extra bridle lines can reduce the flapping significantly if their length is just right: by tempering the sinusoidal waves in the plane just above the kite. If so, then depower should not be impacted.

Makes me wonder if some of those bridle lines should not be bungees instead — for a potentially better combination of flapping resistance + depower.

The suggestion to power up the kite is no solution at all. Why not switch to a fixed bridle kite then? No flapping, ever. Problem solved?

Re: The Firefly V2 mod

Posted: Mon Jul 27, 2020 10:15 pm
by kitexpert
In OP's case line lengths are not "just right" because there is a speed system and new lines are connected to C but located backwards. Kind of hack but because nature of these kites is so crude it will do somehow anyway and at least very probably it doesn't make kite worse (if added complexity, drag, weight and costs are unnoticed).

However there is some AoA in which new lines will support canopy, but if there was a correct pulley ratio available it would be better.

Also LEI kites flap if there is no struts or only single strut, and even five strut kites flap to some degree. But six strut kites like for example Best Taboo and Cabrinha Nomad were pretty smooth and solid through the turns.

Powering up is some kind of solution and many ss kite users use very small sizes well powered up. But if wind becomes too strong it is good to have depower even if kite is fluttering and bar vibrates in your hands.

I don't know a good answer to single skin kite flapping. If there is no struts, battens or cells there just isn't chord wise rigidity to prevent flapping when kite is depowered

Re: The Firefly V2 mod

Posted: Mon Jul 27, 2020 10:34 pm
by AndersP
I believe br44 are right. Braking the flutterwaves or making them smaller will increase the performance.

Re: The Firefly V2 mod

Posted: Mon Jul 27, 2020 11:31 pm
by PrfctChaos
Anyone tried little "twigs" or battens on the trailing edge yet? Like you see one trailing edges of some lei's?