Construction Part 1
After I laid out the main features on the base with a red marker, I routed the necessary chanels with a Dremel using the small base attachment that comes with the tool and a 1/8 inch bit. I clamped a ruler down to the foam as a straight edge. This made for some very accurate and clean cuts. The engine mount structure and the uprights for the rudders are all glued into routed grooves.
The servos sit in routed cavities and are firmly screwed into balsa blocks which are glued down to the foam. I free handed the holes for the rest of the RC gear. The routed cavities for the RC gear worked out real well. They can be easily removed when necessary but donít slide around or come loose.
For extra stiffness, you can use balsa strips glued into routed cavities It wasnít necessary on this craft, but I did this on a future design to stiffen the compromised structure of the foam around the lift duct hole.
The engine mount is a simple 1/8 inch plywood stand which bolts directly to the engine. The fuel line simply connects underneath the engine to a connector on the carburetor. It may be a good idea cut out a hole in the back of the mount to better feed the air intake even though there is clearance as it is. The main engine mount is supported by the four balsa braces, which are also mounted in routed slots in the foam.