Some of the major changes are increasing the wing area by extending the wingspan by one extra rib bay The wing cord is wider by 2 inches made by widening the ailerons , The fuselage front section and engine location is 2 inches shorter , the rear part of the fuselage is extended by about 8 inches and split into 6 bays instead 5. These changes are to get the cg location in the right place with the 503 and original light tail surfaces.
One of the big design challenges (not at all related to the towing purpose) was that I wanted to use push rods for all my controls, with a lot of components located in the rear fuse section behind the seat and must be accessible . This is practically impossible, if left square, all is covered with fabric and even with turtle deck and some opening in the front working inside would impossible. This is how I decided to make the turtle deck out of fiberglass and removable. Now I have easy access to all the controls and the parachute, also the location of the chute can be moved easily to the rear if cg needs to go further back.
Here is the control system in mock up stage, I’m trying to work out the flaperons but final version will be probably without the flaps , I will just find the best position for the most climb and leave it permanently set.
Same thing from a different angle.
The headrest is a separate part, I tried to make this front part as strong as reasonably possible for pilot protection in the event of roll over accident,
I did some changes on the tail lay out. The main center rib is about 8 inches shorter. This puts the fin into more straight up position, and moves the ruder about half way over the elevator. The rear bottom half of the ruder angles up about 30 degrees to allow for the elevator movement.