Wing, part 2

-

After dry-fitting the wing ribs, leading and trailing edges, and bottom spar I glue them together. Following this step, and after the glue had dried, I glued the top spar, wing tips, and center-wing 1/16" balsa covering. The wing tips are a simple 1"x1" balsa block formed and sanded into shape.


Next came the tricky part of sanding the center edges of the wing to fit the dihedral angle, and then accurately cut a slot through the spars for the dihedral brace. The rib on both center-facing edges are of 5/32" balsa so that there is enough material to sand down at an angle. I raised the wing tip to half the dihedral angle and used a wide sanding block to sand the edges perpendicular to work bench edge. The slot for the dihedral brace was created by cutting through the spars' length with a mini hacksaw, and then carefully widening the slot to fit the 1/16" plywood brace.

Both wing halves glued with epoxy.


Next, I made room for installing the aileron servo. This is a 9 gram servo that fits nicely beneath the top balsa wing covering. I had to cut a gap in the center rib, so I made sure I did not epoxy this area. In order to reinforce the center I added two half-ribs (trailing edge to spar) on both sides of the servo and made sure I left room to route the servo's wire harness.

Next I covered the bottom of the wing with 1/16" balsa sheets, and glued the servo holder (1/16" plywood) with epoxy.





Comments

Post a Comment

Popular posts from this blog

Wing, part 3

-
Image
The last step before final sanding and covering was to fit the wing with ailerons. The ailerons run the entire length of the wing, and have a width of approximately 12% (1/8) of the wing cord. The ailerons are fitted with two nylon hinges, and are actuated by a steel rod. Next step is a thorough sanding of all surfaces, then covering the wing with Monokote. The ailerons will remain in natural balsa, sealed with Dope or Sanding Sealer.
Read more

Wing, part 1

-
Image
Before setting out to build this plane I decided to make some changes and adapt it to the 4-channel plane I want. It is going to be equipped with an electric motor rather than a glow-plug 0.049 engine, and I have some modifications planned for the fuselage. The wings will be equipped with ailerons to make it a true 4-channel model. The original kit had an optional add-on aerobatic aileron-wing with a semi-symmetric profile and no dihedral. The wing I decided to build will have a ~3 degree dihedral and wing-length ailerons. To accommodate the ailerons I made some minor changes to the trailing edge seen in the picture, and printed a rib template from PLA on my 3D printer. The trailing edge spar I used is actually 1/4"x3/8" and not a 1/4"x 3/4" as in the picture. I cut each rib using the template, which was my first mistake. It takes too long, and if you're not careful to check each one they may not match. A better method would be to "sandwich" rough-cut
Read more

Completed

-
Image
After eight weeks the Electric Banana is complete and ready for a maiden flight. AUW: 620 gr / 22 oz and powered by a 1300 Kv motor, 30A ESC, and a 3S LiPo/2,200 mAh battery. Wing span of 38 inches and a wing cubic-loading of 10.6. Power measurements with an 8x6 propeller showed a maximum full-throttle input power of approximately 140W. Assuming an efficiency of 80%, would yield about 110W maximum. According to my calculations this is more than sufficient for a basic 4 channel training and some aerobatics. Some pictures after an outdoor taxing test.
Read more