Introduction: How to Make a RC Piper J3 Cub

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Hello Everyone,

After making my very first model of Cessna 172 which was a huge success I thought why not make another model which is bigger, more advance, looks beautiful and is easy to make. I personally think that Piper J3 cub is an absolute beauty and it would be really amazing if I could make a small scale version of it. I looked for the model on the internet and decided to make my own plans with a few minor adjustments.

I'll be sharing the plans and my experience on how i went about making this beauty, please feel free to checkout my previous instructable on Cessna 172 to get the basic understanding of the electronics and their installation in depth.

Aircraft Specs:

Wingspan: 130 cm

Chord length: 18 cm

Aspect ratio: 7.22

Total length: 100 cm

Thrust: 900 gms

Flying weight: 1200 gms

CG: 7 cm from leading edge

Supplies

For making the model

  • Foam board 5mm
  • Hot glue gun
  • Cutter & Scissor
  • Metal wires for landing gear and control surfaces
  • Plastic control horns
  • Packaging tape yellow & black
  • Rubber wheels 55 to 70 mm
  • Velcro
  • 5mm Plywood 8 X 14 cm
  • 1045 propeller

Electronics required

  • RC transmitter and receiver 2.4 GHz at least 4 channel
  • 900-1400 KV brushless motor
  • ESC 30 Amps
  • Lipo battery 11.1 V, 3S, 2200 mAh
  • 4 micro servos
  • Some servos extension and Y harness extensions

Step 1: Design and Schematics

Here are the Schematics for this plane that I created, copy all the parts on the foam sheet and cut them using a cutter.

Please refer to the schematics for dimensions and further reference

Step 2: Making the Fuselage

To make the fuselage we will use part 1A , 1B and 1C .

Glue these parts as shown in the pictures, we will also be using 2 foam cutouts of length 10 X 10 cm to give the structure of the internal strength and divide the fuselage into three compartments as shown in the image.

Currently the entire bottom of the fuselage is a secondary and internal platform on which the main landing gear assembly will be glued, once we are done with making the landing gear assembly we will stick another layer of foam to cover the fuselage bottom.

Step 3: The Tail Section and the Motor Mount

For the tail section we will need part 2A and 2B to make the horizontal and vertical stabilizer.

To make the elevator and rudder first cover one side of parts 2A and 2B and make a partial cut on the dotted lines on the other side and make V cut in the foam so that the tape acts as a hinge and the control surfaces can move in both the directions, once done tape the entire parts as shown in the images.

To make the motor mount take a 7 X 7 cm plywood and mount the motor in the center using screws provided with the motor.

Now glue the horizontal and vertical stabilizer to the tale section as shown in the picture.

We will also now glue the motor mount in front of the fuselage and cover the entire fuselage with yellow packaging tape as show in the pictures.

Step 4: The Main Wing

This is a very important and a bit tricky as the quality of the wing will determine the flight characteristics of the plane.

For this we will be needing part 3A , 3B and 3C.

To make the wing cover part 3A with packaging tape on one side and then flip the side make dotted line as shown in the schematics and fold along it to give the wing its shape, be careful not to break the foam while folding it.

Once you get the crease stick two strips of foam which is part 3B along the total length inside of the wing, glue the wing using the hot glue gun so that its firmly packed and remains in the shape of the wing as shown in the pictures.

To make the winglets cut 4 pieces of part 3C and glue them to the wing as shown in the pictures.

To make the ailerons we will make 2 partial cuts of 45 cm on both ends of the wing, make V cuts and use packaging tape as hinges so that the ailerons can move in both directions.

Step 5: The Landing Gear Assembly

To make the landing gear assembly refer to section 4 of the schematics and bend the 5mm metal wire and attach the wheels using washers and nuts you can use different methods and your ideas to make this part since their are many different ways to make landings gear, once done attach it to the plywood and glue it to the fuselage.

For the tail dragger attach a small wheel using a metal axle to the rudder.

Step 6: Installing the Electronics

In this step we will be installing the servos, ESC and battery compartment.

We will be installing 1 servo each for the elevator, rudder and ailerons.

Install the servos and control assembly to each control surface keeping in mind the neutral positions of each control surfaces.

Connect ESC to the motor and connect all the connections to the receiver as follows -:

Channel1 - ailerons

Channel2 - elevator

Channel3 - throttle

Channel4 - rudder

Install the battery in the front compartment using Velcro.

We are now ready to test all the functions and control surfaces .

Step 7: Putting Decals and Finalizing Everything

We are now almost done and only need to cover the bottom and the top of the fuselage with foam, make a removable top section for the front compartment where the battery will be placed and cover the whole plane including wing in yellow tape as shown in the pictures.

For the decals i used black tape and made the decals looking exactly like the piper j3 cub and I think its looks awesome.

We are now ready to attach the propeller and go out for the maiden flight.

Happy Flying !! Enjoy!!