6 Ft Cub - Scratch Build

I have been flying RC airplanes for the past 19 years. I started with a Lazy Bee glow plug plane and have had the passion ever since. 

I have bought and built many planes over the years.  I stuck with foam based models as they are easy to mend or replace if something goes awry. I found myself getting bored with just purchasing something in a box and putting it together in a few minutes, so I set off to build something, and it had to be big!

I wanted to start off with an 8-foot wing span but found that I should probably start out a little smaller and went with a 6-foot wing.  I purchased a 4 x 8 sheet of two-inch foam and brought it home.  You can get many different types of foam board at your local hardware store. 

Scratch build

I started by creating the fuselage by laminating several smaller pieces together with Gorilla Glue. Next I cut out a massive 6-foot wing twelve inches wide.  I had no idea how it was going to turn out because I was not using any plans at all, just a old fashion "eye ball."  

I used a hand saw and sand paper to mold it into some semblance of an air plane.  I shaped and sanded the wing into a standard flat bottom air foil.  Originally it started to look something like a Cessna but didn’t look quite right, so I added more foam and it took on its current shape, more like a cub. Originally I wanted it to be solid foam but ended up hollowing it out to lighten it up a bit.

As it began to take shape, I realized the wing needed some support.  Dowels were added for strengthening the wing, they were also used as anchors for the wing, I chose to use rubber bands to secure the wing to the fuselage to give some forgiveness in case of a wing tip landing. I cut out the ailerons and used hinge tape to secure them. Later I added some plastic hinges. 12 gram servos are used throughout the build.

I decided that this plane was a cub and cut out the correct style rudder and elevator.  I had no idea how to attach it so I bolted it on, literally.  I found some plastic screws and nuts and counter sunk them into the foam with Gorrilla Glue.  It worked great.  I needed a way to hold the rudder up so I took a 2x4 to the table saw and started creating a custom tail holder.  A little hot glue and it was solid.

Glide test

By this time, it looked like a plane. So out to the back yard we went, a few glide tests worked out pretty well.  It was time for a firewall and motor.  I decided that I would use a motor that I was familiar with, from my largest plane, the E-Flight Apprentice.  That motor seemed to have plenty of power so I thought it would get this bird in the air just fine, although it was probably 25 percent larger.  I cut out a block of wood with a downward and right angle approximately 2-3 degrees in each direction, and screwed it on.  Sticking with what I knew, I also used the same ESC and similar battery from the Apprentice.

I bought a simple aluminum landing gear set, some foam tires, and a tail wheel from the local hobby shop.  I debated on how to paint or coat the foam as it looked a bit rough.  Ultimately, I decided to use some yellow colored tape on the wing for strength.  It turned out beautiful, so I decided to continue the look on the fuselage.  I added the classic Piper Cub lightning bolt and made some windows with black tape.

The plane was complete, I checked the center of gravity and to my surprise, without having to change a thing, it was perfect. At least I thought.

Finally, the day had come for the maiden flight.  I live next door to the local airport and they let me use the runway.  My wife and son by my side and she said, “Honey you should take a picture first.”  I knew what she meant by that as it may be the last time we saw it in one piece.  A few pictures later and we were ready for takeoff.  My heart was beating so fast on that first trip down the runway.

Maiden flght

Full throttle and lift off! to my surprise the dang thing was flying.  It seemed a little tail heavy so of course I was concerned.  I adjusted the trim quickly and she flew like a dream.  I flew the plane all summer long without any issues.  I realized that the Apprentice motor was just not quite big enough to do anything but keep the plane afloat so I upgraded to an E-flight Power 32 motor and a 14-inch propeller and a 60-amp ESC and it preforms almost like a 3D plane.  I can fly upside down, do loops, you name it.  I have been using 3 cell batteries ranging from 3000 to 5000 Mah.   I have also upgraded the landing gear to 6 inch Dubro Tundra Tires and light steel landing gear.

Over the past year, the plane has evolved for the better by adding flaps for super short take-offs and landings.  I hope this inspires you to go out and build what ever you want.  This summer I will be building something even bigger, a Lockheed U2 with a 117-inch wing span, and you guessed it, all FOAM!

Dimensions: Fuselage 42” long 6” tall at highest point and 5 ½” wide.  Wing 72” long 12” wide.  Rudder is 9 inches tall.  Elevator 24” wide. Total weight about 7.5 lbs.

Thanks to:

Dubro "tires" https://dubro.com/collections/tires-wheels/products/big-wheels

Tape Planet http://www.tapeplanet.com/2-inch-x-55-yard-2-0-mil-Colored-Carton-Sealing-TapesTapes-s/241.htm

FliteTest for inspiration! https://flitetest.com/  

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