Banana, build log of a 4ch RC trainer

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.

Finally got my covering tools delivered. The covering iron was much easier to use then the household iron I tried before, and the hot-air gun was a huge surprise. I've never used hot air to stretch Monokote (or Monokote-like) covering, but the results I managed to achieve would not have been possible by simply using at iron. After completing both sides of the wing I decided to adorn it with some decorations. The bottom of the wing will get a checker box pattern in red, and the top of the wing will get a few red stripes to break the monotone yellow. I am using the Windex method to activate the glue and fix the red decorations to the yellow covering. I was told that I could do this only with original Monokote covering material, which is what I am using. So far, the Windex method works well, the liquid dries up, and the squares seem to be securely fixed. The fuselage finish has a natural balsa look with only a few coats of varnish. I am using Sanding Sealer for this instead of Dope, w

Completed the fuselage: Added Balsa "fuel" tank cover that fits with a small peg and braced with the original setup of screws and a rubber band. The ESC will be mounted on under side of the cover: All the parts combined for a complete view: Next step on the fuselage will be setting up motor, ESC, routing power wires, transmitter location, and placing the battery for initial balance and weight measurement.

Once the bottom sheeting was dry and sanded down I turned to the internal setup for servos and push-rods. I followed the blueprint for rudder, elevator, and push-rod setup, with the exception of the smaller servos and lighter rods. Elevator and rudder are centered and all rods in place and functional:

Still waiting for my covering iron and heat gun to arrive in the mail. Holiday shipping has really gone wrong this year. I decided to start building the fuselage instead of sitting around and waiting. I reviewed the plans to mark up all the changes I needed to make in order to convert the plane to electric power. The changes will accommodate a 3S/2,200mAh or smaller battery, a 30A ESC instead of the small fuel tank, and replace the original servos with new 9[gr] servos. My overall weight estimates of the electronics and power system came out to be slightly in favor of the electric setup: 310 [gr] vs. 360 [gr] of the original, without fuel. The main changes included: a larger fire-wall to increase the front opening width for a battery, moved the second rib back 20 [mm], and fashioned it into a rectangle with an opening made out of ply wood. Glued together with bottom longerons: Next, completed bottom sheeting after gluing the fire wall in place with appropriate down and right thrust:

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.