Who should be interested in a good lift-to-drag ratio and therefore to find a possiblity to compare it quantitative?
Low drag and therefore a good l-t-d ratio is the key to not just lowest wind, but also to be able to use the smallest kites.
The less drag you have the less pull you need.
For example ridding 6 m² in about 10 knts with fun: https://www.youtube.com/watch?v=STWet7fLx5Y
Drag is caused by the main three factors:
- surface friction, depending mainly on surface size off all parts in the water
- frontal area, mainly limited by strength and stiffness of material
- induced drag, increasing with low AR wings
My question is, are firms or others testing just this ration in clean conditions for example behind a boat or in a pull test water tank or similar? And what are the values?
For kites like the old speed 1, I remember a test with a pick up truck 10 years ago, resulting it has a ratio of about 6, while tubes of this time had about 5, done by a kite magazine with the help of a aeronautic ingenieur / kite designer.
What's about with foilboard industry, any repeatable test and numbers around?
Motivation for my question is, without knowing its number a few days ago I think I nearly accidentally tried a foil with a close to the best actual possible and ridable ratio, showing the picture below,
but also would be interested in numbers of any anchor foils as old alu or carafino, airchair, etc. or even twintips and doors ...