Slope Scale F-20 Building Pictures

These are pix of the building of my Cavazos Sailplane Design Slope Scale F-20. This was my first Slope Scale plane but will not be my last. I really enjoyed building it. The ship turned out well and I learned a lot about building as well as finishing. I may do a few things different on the next one (a CSD P-51B) but, mostly, I am happy with how it turned out.

Special thanks to Dave Garwood for answering several questions. His experience made my job easier!

The first thing I did was to sheet the wings. I vacuum bagged them with epoxy and a layer of 1.7 glass in between the 1/16 balsa skin and the core for good epoxy adhesion.

The vertical stab was reinforced with basswood leading and trailing edges then sanded to an airfoil shape.

Same idea on the horizontal stab.

After I glued on the basswood leading edge and shaped it and glued the balsa sub trailing edge on, I installed the torqe rod setup.

I beveled the aileron leading edge to shape.

I made these brass bushings for the ailerons to receive the torque rods.

The holes in the foam cores are just there to help hold epoxy in.

A Slope Scale plane can’t be too strong so I added a layer of this 4.8 ounce or so Kevlar/Carbon material from the wing saddle forward. I used laminating epoxy and it worked well.

Here is the vertical stab being mounted. Make sure it is straight!

The horizontal stab is ready to mount. You do have an incidence meter, don’t you? I covered the stab, as well as the wings and vertical stab with an iron covering called Lite-Fab, just like Solartex. It was very easy to work and went around the curves easily. It also takes primer very well.

It is starting to look like an F-20!

Here, the aileron push rods have been installed prior to gluing the wing on. I tried the aileron servo in the wing. Don’t do that if you are going to glue the wing on. Access to the servo in case of a problem would be tough. I put the aileron servo just forward of the wing in the fuse.

Primed and almost ready for paint.

I used West Systems fairing filler and epoxy for the fillet. Bondo probably works as well or better.

My buddy, Steve, did the main tiger scheme.

Some of Steve’s other art!

Top view

Bottom view

Radio installation

I still have to do the weathering thing to the plane but it has already been out several times. I takes a pretty good wind to make this puppy happy but it is a blast in good lift. Finished weight is about 45 ounces.