When you are assembling the carbon fiber pushrods and the servo arms, you may find it helpful to clamp the control surfaces so that they are perfectly flat; no up or down and no left or right.
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.
Just a short video to show the action of the external pushrods on the FT Simple Scout.
Already admitted that I am not good at free hand cutting the bevels on control surfaces. So instead I have been cutting off part of the foam board and replacing it with balsa. In this case I took a 3/16″x3/8″ strip and cut a 45° bevel on the table saw. So as shown below, the aileron is separate from the wing. Vertical and horizontal stabilizers work the same way. Then I use brown kraft tape to attach the pieces to one another for the control surface hinge.
A large foam board model with some interesting construction ideas.
After you remove the fuselage sides from the building board the next step is to glue in the cross members. An earlier post showed how to accurately cut the cross members using a guide. Next step will be to glue the cross members in. If the wood was larger than 3/16″ we might use building pins to hold the parts together while they dry, but with small wood sizes you run the risk of splitting the wood. So instead I use tape.
i had a question about tracing lines from the stab slots onto the balsa below. Here is a step by step. I used a small hobby table saw to cut the balsa. And then a small 5″ disc sander to clean up the edges. An X-ACTO saw and some sandpaper will do just as well.
Just a couple of details about building with balsa sticks. Longerons are the long, weight bearing elements. The cross member supports add to the strength of the structure and also make assembly easier. The 3/16″ balsa tab fits into the horizontal stabilizer. If you view the plans for the Flitetest Simple Scout you can see where the balsa tab replaces the tab from the foam board fuselage side.
The bottom of the fuselage on the Simple Scout runs at an angle to the tail. So when cutting the balsa sticks the bottom needs to be cut at the same angle. The top of the stick is square, so no need to cut an angle. I made this cutting guide from a couple pieces of scrap foam board and one piece of 3/16″x3/16″ balsa stick. Just make your mark, then cut or sand the stick and glue it in place. Works really well to give you nice tight joints.