On Monday, November 11, 2013 12:36:33 PM UTC-8, wrote:
Didn't Will Scheumann do this in the 70s? I remember a soaring cover photo with a weird sort of mortocycle grip on the stick. As I remember, the basic idea was that the pilot pretty much flew by flaps, changing flap setting to induce changes in CL, with the tail functioning as trimmer.



Now if the windward guys really want to get fancy... you can in principle extract a lot of energy from the air by dynamic soaring the small bits of positive and negative g we run in to all the time. Humans are too slow, and we don't have the feedback we need, which is knowing when the lift vector has a component in the direction of motion to pull, and a component in the opposite direction when you push. This could be automated, lots of little fast pitch motions. Purists laugh, but if you get 60:1 glides out of 15 meter with high speed automated pitch motions, they'll laugh all the way to the back of the scoresheet. Or, I guess, to the annual rules poll to get it banned...



John Cochrane

It all needs to be balanced. We learned a couple of decades ago that doing a lot of hard maneuvering generates more induced and separation drag that it gains in energy extracted from the atmosphere which is why no one does big, sharp zoomies into lift anymore - or if they do they pay a heavy price in glide performance. I suspect it is also why you need a pretty sharp gradient for dynamic soaring to work so you don't lose more energy than you gain pulling all those Gs.

In terms of optimal flap setting, I suspect the gains are small unless you are prone to go long distances with the flaps set wrong (I admit occasionally set off on cruise in thermalling flap - oops!). I don't think setting them dynamically would make a ton of difference since you are ill-advised to make that sharp a change in attitude in the first place. If I were designing an automated flap system I'd put a low-pass filter on the inputs with a big (several seconds) time constant.

If I remember correctly, Wil had an ASW-12 that somehow used the flap handle to set pitch attitude at cruise. It was a different era so I don't know that the lessons would apply to today's designs.

9B