RE: retracts on a rapier delta?
Caliber,
Fig.1) This shows where the ply reinforcement goes...either side of the main rib (pink). Or you could cut out the balsa wing area (black) and substitute for 1/8th ply to the same profile and epoxy into place.
Fig.2) This is a plan view of the reinforcement ply positioning.
Fig.3) The black block areas need to be cut out for the hardwood undercarriage supports. The pink area shows the retract positioning.
I'm not sure if you have decided to go for a fixed or retractable nosewheel?
Note: The Rapier would probably be too tail heavy if the wheels where fitted further back. You will maybe need to move the flight pack from the rear to the front with retracts fitted, hence a heavier/more powerful engine will be needed ( eg .46/.53 Irvine although these are the same weight!).
Should look interesting with retracts fitted![8D]