very interesting Taul Paul. I guy at my club was suggesting I look into automatically moving slats - he said they work well on tiger moths, but I had my doubts.

Imagine if one stuck down and the other stuck up.... could be nasty

And again I totally agree with your comments on weight. There is absolutely no point going down the road of more servos and more control surfaces if there is no gain over having a simpler wing at a lighter weight - on a competition model especially.

The trouble with flaperons though is adverse yaw - which is why i advocate upper surface spoilers and full span flaps if you are going down the stol route.

Slats are interesting though - you get an increase of max Cl coupled with a massive increase on stall angle.

Andy Lennon made his slats fixed - so that they were always open. I suppose this would increase profile drag a lot - a bit like a paraglider wing with an open leading edge.