Thank you gentlemen... good stuff all 'round. Here's the plan for now... first wing will have single element Fowler flaps with the following action...

• First, flaps will do most of their rearward movement (probably 75% or 80%) while they rotate the first 10 degrees and open a slot as specified in the NACA documentation. (In this stage I expect increased lift without significant drag penalty for shorter takeoffs).
• From there, they will continue rearward as they pivot to as much as about 25 degrees. (In this phase, I expect parallel increase in lift and drag to allow slower speeds with little further effect on glide path... may be useful if wanting to extend an approach).
• The final stage of deployment has the flaps already translated to their full rearward positions and involves only rotation toa total deflection of 40 degrees or, perhaps, a little more, (In this phase, increased drag outstips continued increases in lift for slower glides at steeper decent angles).

I'm planning on implementing all that by having leading edge and a point on the body of the flaps pinned, and the pins riding in curved tracks/guides that will force the correct placement and angle... they'll be actuated by feed screws that will keep the all ends at the same location relative to their travel.

So, there's probably pros and cons involved with the details... how can I improve the implementation concept?