Bushflyr wrote: ↑
Sun May 06, 2018 7:05 am
No, all the front lines will share the load regardless of pulleys or no.
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.
@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!
Let's do the same with a pulley system
Assume now all lines have a load (not the same but have a few Newtons - not just the deforming of the front tube)
Now you increase the angle of attack. (that is the trailing edge going down - back lines pulling more)
Instead of line 4 going slack, the pulley will move closer to 4 and change the whole geometry giving some load to line 4.
Therefore, this changing geometry makes the system more tolerant in small stretches/shrinkages. (Pulley will move and compensate - as long as it does not hit a stopper)
@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.