Tarun's RC Plane
The goal of the empennage is to be readily assembled and have a rudder that allows for yaw control of the plane.
The main design feature of the empennage was the rudder. In order for the servo to control the rudder, the rudder needed to be able to rotate freely, and with as little friction as possible. Additionally, horizontal stabilizers, with symmetric airfoils, were added to improve the stability of the aircraft.
Design Attempts
Attempts: a prototype of just the vertical tail and rudder were printed to ensure that the joint between the two parts was a viable design. This attempt failed many times due to small pieces being knocked down by the printer nozzle. Solutions to fix this problem included reducing the filament flow rate to combat over extrusion, and adding supports to parts with a low bed contact area. What finally solved the problem was wrapping supports all the way around the weak parts.
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Attempt feedback -
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increase clearance between top and bottom of rudder and corresponding surfaces of the vertical fin.
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Increase area of vertical fin and rudder.​​
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Increase servo wire attachment area.
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Most importantly, this attempt showed that the joint design works well.
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Fig. 1 - Failed prints of the vertical stabilizer, with zigzag supports in the middle.
Fig. 3 - Vertical stabilizer, note the cone joints for the rudder and the remnants of the printer support on the top and bottom inner surfaces.
Fig. 2 - Succesful print of the vertical stabilizer.
Fig. 4 - Rudder, note the poorly textured top, same on the bottom. Will need to be printed sideways instead. Also, note the servo attachment arm.
Video 1 - Rudder - vertical stabilizer assembly. First working part!
Final Design
The final empennage design features vertical and horizontal stabilizers and a rotatable rudder. Attached to the rudder is a servo arm that was designed and placed differently from previous attempts. Additionally, the back of the empennage is hollow, which allows for a screwdriver to drive the screw which can be seen in the fuselage attachment in figure 6.
Fig. 5 - View 1 of the final empennage.
Fig. 6 - View 2 of the final empennage. Can see the aft landing gear screws and nuts.