Peter - I think that you can argue that it is minimal, or not detectable, but certainly pulleys have some friction, therefore consume some energy. I'm 100% sure of that
Ha haa, I almost waited for that one, so you are right
But would not complicate by taking this "not detectable" value into the discussion
(maybe simplified too much then....)
As we all know this is not the issue here
It could be compared to saying that you got loss because of line stiffness, instead of having "infinite" soft lines
Where the answer to that would be NO, you dont have any loss because of line stiffness (because it is not detectable in any way).
But you could always argue that there would be a theoretical loss because of line stiffness, even though it does not make sense to take into any equation or view at things
The same goes for the pulleys - and the postulate was apparantly that the presence of "working" pulleys should make the kite less powerful, right ?
Which is not the case in any way (measurable )
Okay then, to be more precise:
The presence of pulleys, and the clean "sliding" action itself - DO NOT COST ENERGY !
The friction is of course a really small "heat" loss (energy loss) yes, but it will IMO not be detectable at all (which is a postulate, I know, but based on experience).
That was my point - just to clarify that the pulley principle do not cost energy
The FEEL when turning, can be influenced a lot, and both give the feel of having less power, as well as the opposite - depending on what principle used - but that is another issue...
Corrected my earlier posting, to "pulley principle" instead