Of course they won't equally distribute the load without pulleys if angles between parent branch and child branches are not exactly the same. in above picture if you pull all the way on one of the front lines the maximum load will be on A1
You're absolutely right on #1 but I'm not sure why we'd assume for #2 that equally distributed load on leading edge will be "better"Sandras wrote: ↑Sat May 05, 2018 7:58 pmreo.JPG
My understanding may be wrong and I welcome you to correct it.
I paste the bridle of Reo as an example of a non pulley kite.
1) For pulley less kites only one of the A1,A2,A3,A4 carries the load of the front lines (the rest have a very small load that just keeps the shape of the kite)
A1 (and the back lines) is carry the load at the maximum sheet in and A4 carries the load when fully de-powered.
2) A bridle with pulleys, because it can move it divides the load in the bridle lines.
My though is that a bridle with pulleys is less sensitive to stretch/shrinking exactly because the pulley can move and redistribute the load. That is that even if +/- a bit it would still work better than a pulley less bridle.
Is this thinking correct? If not, what's wrong?
I can't agree on that.
Agreed on load distribution.Sandras wrote: ↑Sun May 06, 2018 10:19 am
@grigorib: You added the word "equally" which makes a big difference. Yes with the word "equally" everything is wrong. But dividing the load does not have to be equal!
@grigorib: I'm not checking if one system is better than the other, I'm not even checking which one is more durable or wear resistant.
All I'm comparing is that if a fixed bridle system gets a bit out of tune because of stretches/shrinkages it will have a bigger effect compared to a pulley system with a bit of stretch/shrink. I see the pulley system as more autoadjusting.
Yeah, just no.Sandras wrote: ↑Sun May 06, 2018 10:19 am
I can't agree on that.
Just look at the drawing below.
Let's assume that at this AoA (angle of attack) it is as you describe it. All bridle lines have load.
Now imagine the AoA increasing (that is the trailing edge going down - back lines pulling more). What will happen to 6 in that case? I believe it will go slack, no?
Now imagine closing even more, now 4 goes slack.
(When I say slack, you wont see it flapping because the leading edge will move/flatten and compensate but this is a very small load, just tensioning the line)
The more the angle of attack increases, the higher the pull in the lines.
My assumption is that in fixed bridles, line 5 will stretch more than the others disturbing the initial tuning. (e.g. more chances to front stall depowered.)
Reading again my first statement and looking again at the drawing above, it now seems to me that it is not a single line that carries the load but there must be a few slack lines in fixed bridles depending on the AoA.
It gets confusing. There’s no pushing anywhere...
Oh, I'm glad that we can talk with vectors!
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