Just checked again, the 64(1)-412 is not documented. And the 6412 looks much too thin for a glider foil (IMO). Looks like I will have to forget about this one.
Why is it that you mention the earlier FX? Not long ago you suggested the more recent FX 79-K-144/17 and AH 93-K-132/15. Was this based upon the assumption that my glider is not aerobatic?
I have read the article that you posted. I can see why the Ribblet airfoils are good but actually it's difficult to find good info on aspects of aerobatics that influence airfoil selection. Would the criteria be relatively similar to picking out an airfoil for a "normal" glider?, I understand I will need high Max Cl to pull Gs and I also understand that I will pay the price by having high Cm and thus relatively big tail/ elevator? Perhaps not such a big problem for an aerobatic glider though?
Sorry for confusion, I'll try to clarify it.
First we should vary a conventinal glider, from a aerobatic jet glider.
For the conventional gliders at the beggining (I'm not talking here about "Flintstone" era gliders) they we using NACA 6x-xxx series airfoils, next they replaced NACA foils with Wortmann ones. Currently they use in most gliders flapped airfoils, DU ones. The point about using flapped airfoils is that, that by changing flap position you changing camber. Thanks to that flapped airfoils are good (high L/D) not only for slow flying (thermalls) but also for fast gliding. And this is probably the biggest advantage over non flapped airfoils. So when you asked about the best glider airfoils you can get for free, I mentioned those two.
But the question is, is it a good idea for your application to use flapped airfoils? (for this reason I posted that Swift movie, during aerobatics there is really no time for "playing" with flaps) Personally I have some doubts about it, but it's my personal opinion. When you mentioned NACA airfoils, my first idea was that maybe some earlier FX ones might be better option, as those airfoils replaced NACA ones, back in sixties.
I understand I will need high Max Cl to pull Gs
For a racing airplane our Orion was using Ribllet 37 series airfoil, when I asked him about it, this was his response.
Orion said:The design point for the race is actually the turn, not the straight, which sort of forces you to use sections that have a better l/d at the higher lift coefficients.
But final decison belong to you, you have to study airfoil polars and decide which one suit better for your application.