One idea I toyed with was using flask-shaped bottles as fuel tanks. These could be buried in the wing structure, and would make for a much smaller nacelle, with the firewall at the leading edge (or even behind it). The WeldBond bottle on my bench was ideal, 8 oz., and made of HDPE. I saw some problems with arranging the fuel and fill lines, so decided to go with more conventional nacelles. Maybe on my next build...

The leading and trailing edges are all sheeted now, just have to install mounts for the flap and throttle servos. I'm going to build slotted flaps, using control horns to get the slotted effect, and power them with standard Futaba 3004 servos in each wing. The throttles will be controlled by Futaba 3115 servos with flex cables running through the nacelles.

I'll be using Robart hinge points for the ailerons , so I added balsa blocks at the trailer edge for extra support. Both the flaps and ailerons will have their servos side-mounted in hatches on the underside of the wing.

I will be fairing in the nacelles using 1/4" balsa sheet, with a removable hatch in the top for access to the tank and the throttle servo.