Maybe I should also have written that all short describtions don't do justice to the fully proces.

Indeed, it was a general describtion as many smaller swirls, eddys and backflows are seen and it is a rather dynamic proces with seperating and reattaching flows. And this is something made even more complex in some setups by the introduction of roll-over vortices and what not. Than modern gliderplane something use compressed air to scrape of a stagnant boundery layer.

The end result if that any discussion that doesn't include the better part of the day falls short of completely describing what happens and thus a discrepency between theory and practice can be found now and then.

Best example was of course the fact that theoretically a bee could not fly while it actually did. That is before it was realized that the wings worked in a different due to their microsize (different behaviour of molecules whch didn't reduce in size of course) and the fact that the wings created strong momentary swirls above the wings.

I know of Marchaj's publications, I must admit however that I never fully read through them.

Nils I'm told that another great source is NASA scientist mr. Arvil (?) who determined (in the 60's, and Bethwaite rediscovered this later)
That the venture (or slot) effect didn't exist. The conclusion was that it is not the jib that makes the main more powerful but rather that the main makes the jib more powerfull. End result remains the same however and that is the fact that a jib makes a rig more powerful than what its size would simply suggest.

I forgot to include this in my earlier post.

It seems that the right position of both relative to eachother is the key to performance and not as much the size or shape of the slot.

Like I said earlier we can talk about this all day and still not touch on every detail.

For now the main point I wanted to get across is most developments seems to refine our understanding of what happens rather than alter it. The predicted results using either methode seem to be the same and therefor which theory your comfortable with is not that important in itself.

Regards,

Wouter