When I built the first FT Simple Scout with the balsa diagonals, I didn’t make slots for the pushrods. The foam board fuse has slots but I thought that I could somehow maneuver the pushrods through all the open spaces between the balsa sticks. I couldn’t find a way to do it. So instead i decided to mount the servos on the outside of the fuselage and use carbon fiber tubes as pushrods.
Make some short Z-bends for each end of the carbon fiber pushrods. Make sure the piano wire is a snug fit in the tubes. Then I used thick CA to fix the Z-bends into the tubes.
If you use a Dremel tool or power saw to cut the tubes you are liable to put some cf dust in the air. You don’t want to inhale that so I use a miter box and hand saw for minimum dust.
The cardboard packing in the servos from FT can be used as a template for cutting the hole in the fuselage. Just extend the opening on each end so that the entire servo with end tabs fits through.
This model is being built as a 3 channel. If you are building the 4 channel version you need to make sure that the servo has room with full aileron down deflection.
The way that the Scout is constructed there is a second layer of foam, the doubler, that you will need to cut through.
The servo arm is in the up position. This makes the line from the servo to the control surface close to parallel to the top of the fuse.
I put the hot glue inside through the bottom of the fuselage. Little bit of a tight fit to get the glue gun nozzle in, but it is doable.