In the July 1947 MAN there is a discussion of free flight swept-forward flying wings. The recommendation was for a rudder equal to 15% of the wing area, and a sub rudder with 5 % of the wing area. I have plans for a rubber powered free flight and a towline glider which do not have the subrudder. The glider doesn't have that large a rudder, and needed special rigging to overcome instability in tow.

Here is alink with pictures of the XFG-1
http://modelbouwforum.nl/phpBB2/view...53dbbee98305ae