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Refit of the Balsa Craft SE5a Airframe for Conventional Servos and Ailerons

balsa craft SE5a   An example of some modifications to the Balsa Craft SE5a airframe build to incorporate a conventional receiver and servo type control system instead of the brick with linear servos.
We also add ailerons to the lower wing and run these with an additional servo.
To complete this modification you will need the items mentioned below, a steady hand, patience and keen eyesight.
For the control system we have chosen to use a 4Ch R415 receiver unit which has the same Molex style connectors as the 5320 servos we are using. The receiver is mounted underneath the battery mount in the engine bay. The setup uses three 5320 black servos for elevator, aileron and rudder.


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4CH R415 Receiver



5320 Servo



Two additional pieces of 0.8mm plywood have been used to mount the elevator and rudder servos. For the aileron servo, some wood has been cut away from the body former to allow this to slide into the cavity in the bottom of the engine bay and again two pieces of plywood have been used to mount it to. The plywood also spaces the servo, moving it back a little so the pushrods line up with the leading edge of the lower wing where the pushrods run along.


From the top we can see the bottoms of the servos protruding into the cavity in front of the cockpit area.

 

As this receiver doesn’t have an onboard brushed ESC, we are using a separate 3amp board which is wired to the throttle servo output on the receiver. The two round pieces are velcro dots which are used to hold the battery in place.


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Brushed 1S3A ESC



Super Fine Velcro Dots



For the addition of ailerons we need to modify the airframe. The ailerons are already marked on the wing and these need to be cut out, trimmed and sanded.


For this modification, in keeping with the design we have chosen to use wooden control horns and these are glued against the rib for strength.

Another piece of 0.8mm ply wood is glued to the rib on the main wing and this will act as support to glue the pushrod guide tube to. Here we are using 0.6mm Pushrod Guide Tubes and 0.3mm Stainless Steel wire for the pushrods. We are using 0.6mm tube so the wire will still slide nicely when the guide tube is bent around a tight curve (refer to images below). The aileron is held in place with three thin strips of blenderm tape on the top surface.

Related Products
0.6mm Guide Tubes


0.3mm Stainless Wire

Blenderm Hinge Tape


The guide tube is glued in place with Epoxy glue and held in place with micro pegs to dry.

The guide Tube is run along the leading edge of the wing and enters the fuselage through holes which have been drilled in line with the leading edge.



The pushrods are bent and fed through the holes in the servo arm. Using the hole closest to the centre still gives an adequate amount of travel and will also allow the bottom cover hatch to close to cover the servo arm. The tip of the servo arm has also been trimmed off.


The completed rigging. Using masking tape to hold the control surface in place in the neutral position will allow you to cut the control rods to the correct length and attach them to the servo arm with the correct length.


The completed conversion


Some sample flight videos below. Note that as always, and particularly relevant to this airframe, mixing in some rudder with your aileron inputs will give the best results for turning. Seasoned professionals will tell us it’s easy to do this with their thumbs in flight. For the rest of us, you can use the mixing function on your transmitter to automatically mix in some rudder with your aileron movement.

Test Flight with Ailerons


Take off and Landing with Ailerons.
I also demonstrate an attempted aileron / barrel roll here. It's not realistic for this plane to be able to do a barrel roll just because you have added ailerons to it. I’ve shown you what it looks like here so you don’t have to try it yourself with your plane.