Electra-10 Airplane – Part 2

May 2012 – Amazing Wonders Aviation VBS Prop

The first piece of Insulfoam I cut out was the two tail fins. This taught me a lot about precision foam cutting techniques. I had to dial in the heat in the cutting blade so that it sliced but did not melt away a half inch gap. The difficulty was that the foam block was 4″ thick and while I traced the outline on one side I could not see if the edge of the knife was following the outline on the other side. I overcame this on my next cuts by having Ben hold the far edge with a pair of lock pliers to guide the cut along the outline. Ben has a great amount of experience in sanding and shaping foam. While his subjects are usually miniature houses and small scale, the same principles apply to large scale. By sanding down the rough block cut we achieved the smother beveled edge look we were going for. I have high hopes that once the foil and metal tape are applied the Insulfoam will look like a metal plane part.

  

Using an extra block of foam from my Easter Crosses project I made a mock up of the planes skin. I would use an incredibly long roll of 12″ foil, each sheet would be spaced an inch apart to allow contact between the metal plumbers tape, the foam, and the foil. This would bind it all together and by running the sheets in parallel with the structure of the plane it would create the illusion of metal skin.

As I approach the main build I decided to make a scale paper blueprint of the plane. This would allow me to place the integral superstructure inside the drawing and pull wing and tail measurements without converting for scale. I found some extra gray butcher paper in our children ministry closet and began to lay out the plane. First the main body, then each wing, and finally the tail and engines. The mega-blueprint folds up into a nice two foot square.

  
  
  

Superstructure

A lot of time and effort has gone into the design of the interior superstructure of the plane. Since this 12′ long vehicle will be hung at least 14 feet in the air inside our worship center, safety is paramount. The main cross beam will be 6′ piece of half box unistrut conduit. This gives the main body of the plane a 6′ width allowing it to fit through a standard door. The plane will be assembled in four large pieces.

1. Main Body: A six foot wide section of wing containing both engines, this piece will span from the nose of the plane to the cross beam for the tail.
2. Tail: The five foot wide tail section will bolt onto the main body.
3. Left Wing: A four foot piece of unistrut will be embedded in the wing and have a 1′ overlap with the main body cross beam.
4. Right Wing: A four foot piece of unistrut will be embedded in the wing and have a 1′ overlap with the main body cross beam.

As this diagram illustrates, the unistrut (orange) will be made in three pieces to allow the wings to be both removable for transportation yet securely fashioned to the main body at the anchor points.  Down the main body of the plane will run two corner metal flanges. One on the top, and one on the bottom. Each 10′ flange will be nailed into the front and rear foam pieces as well as the center wooden cage section. The center cage will connect the foam pieces to the metal unistrut and bear the weight of the plane onto the landing gear and the two main anchor points.

  

 The next step will be main assembly of the center body and the wings. This will be comprised out of cardboard spars constructed around the main unistrut beam. A paper skin will be stretched over the spars and eventually everything will be covered by foil and metal tape. The first priority is safety, the plane must hold together with enough rigidity and strength to support itself from the anchor points. Part 3 will have some great progress pictures of the engines and the plane fuselage.

Related articles

• Electra-10 Airplane – Part 1 (thecardboardworkshop.wordpress.com)

Electra-10 Airplane – Part 1

May 2012 – Amazing Wonders Aviation VBS Prop

As I continue to work on my backlog of cardboard projects I  though to myself “Darren, I know you want these to be logged in chronological order, but why are you denying people the joy of following your latest cardboard escapades in near real time?” I then decided to write a series of posts on my current project as it progresses.

This summer our Vacation Bible School is using the Amazing Wonders Aviation curriculum from Lifeway. And as I have done in each of the past four years, I am lending my creative cardboard abilities to the team. We had a volunteer rallying meeting to get people interested and plugged into the decorating projects for this year. With a larger team we are dividing up the work into small groups.

• Worship Center airplane hanger stage decoration
• Craft kits
• Hallway great barrier reef decoration
• Classroom northern lights decoration
• Classroom victoria falls decoration
• 1/3 scale Electra-10 airplane of awesome

As you can imagine I am on the Electra-10 Team, joined by my creative friend Ben who excels in miniatures and detail work. We decided to create a 1/3 scale model of the Lockheed Electra-10 airplane from 1937. This is the same plane used by Amelia Earhart for her flight around the world.

The Electra-10 comes from the classic days of aviation and fits our needs perfectly. It instantly conveys that 30’s-40’s nostalgia for prop planes and simple times. Ben found a set of blueprints online for the Electra-10 and we began our strategy for construction. I set the blueprints at a scale of 1 inch to 1 foot and overlaid a yellow grid for reference. This allowed me to take measurements directly from the blueprints. Fortunately many of the

I was fortunate enough to see this magnificent plane in person at the annual Planes of Fame air show in Chino. We will be using the all silver design with some red accent stripes which were common at the time. The actual Electra-10 has a wingspan of 55ft and a length of 38ft, our 1/3 scale model will not be nearly that size but still feel substantial when hung from the worship center ceiling. Clocking in at 17ft across, 12ft long and 3ft high a modular design is required in order to fit the plane through the double doors of the building.

Materials
The plane will be constructed out of cardboard, foam, and wood. The center part of the plane will have a wooden skeleton for hard mounting the hanging wires.

The front cockpit will be entirely made of foam carved from a 2’x2’x2′ block. Also made of foam [indicated in yellow] are the propellors, engine blocks, tail fins, wheels, and about 70% of the main body carved from a 7ft block.

1:1 scale templates were made with scrap vinyl and transferred onto the foam with sharpie. These will be carved out with a hot foam knife.

The main wings and the tail wings will be constructed similarly to how a real plane is made. The vertical spars will be fashioned out of cardboard skeleton, covered with either mylar or large sheets of foil. I expect the plane to be assembled out of four large parts: 2 wings, the entire foam tail, and the main body with engines and cockpit.

The next stage will be to carve out the props, tail fins and cockpit, and shape the main fuselage. I’ve gotten very good at taking progress pictures and short video clips to document my cardboard creations, so part 2 will be coming out soon.

Gallery

Foam Easter Crosses

April 2012 – Easter Stage Set

“I’ve been thinking of expanding my mediums to foam.”

With this simple sentence I doubled the number of materials I work with here at the Cardboard Workshop. Now i’m not changing the name of this blog to the cardboard/foam/other stuff blog, but I am excited to try out this new medium.

The project was to construct three foam crosses for the main stage during Easter. The design was based off of our branding, three spindly crosses with askew cross beams. Our tallest cross would be 12′ so we reached the point where scale mattered and I created a photoshop document with foam pieces overlaid with the branding. This gave me a sense of the scale as well as how much foam we would need to acquire.

We placed an order with Insulfoam for three 12″ x 12″ x 120″ (10ft) foam beams and three 12″ x 12″ x 72″ (6ft) shorter pieces. This would give me a little wiggle room and some extra space to practice some of my first foam cuts. Cutting foam is very different than cutting cardboard. With cardboard you just need a good razor blade and a flat surface to make any cut. I have gotten very good at crafting my cardboard creations, the knife does what I want it to almost 90% of the time. (Which is pretty skilled) But foam is a new surface to me, it needs special hot knife tools that melt through it more than cut. Our Children’s department had acquired a set of basic hot wire tools from the Hot Wire Foam Factory for cutting, slicing, and trimming high density foam.

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The Foam Arrives

Our foam arrived delivered from Insulfoam shrink wrapped in sets of three. This foreign medium stood contained in our office for a week as my schedule cleared and I formed my plan of attack. I transferred my scale measurements onto the first 12′ block using the grid method.

Our media department has a large cargo shipping container we store most of our extra gear and tools. There was just enough clear floorspace to use as a simple workshop for the foam cross project. Now this part is very important so it will be marked in large bold font.

Always cut foam in a well ventilated area. I cut mine outside with a breeze or a large fan keeping the fumes away from me. Cut foam will produce fumes and proper safety precautions must be taken.

Now with that out of the way, I began my first cuts with our blue industrial hot knife. This tool was great, it cut very quickly and was easy to clean with the included wire brush. I shaped down the main beam into a rounder shape by repeatedly trimming corners. This took he shape from a square (4), to an octagon (8), to a hexadecagon (16) and so on and so forth.

Next I cut a large notch out of both pieces of foam and fit them together into the cross shape. The final detail work was done with the freehand router tool which gave the foam a beautiful rough wood texture.

Painting and Stands

With Easter fast approaching I enlisted the aid of my media team friends to help with the final texturing, painting and mounting the crosses on bases. A quick trip to Home Depot secured some 2’x2′ wood bases, which we ineffectively tried to scan in the self serve lane.

Jesus and Joe applied the first test coats of paint on the crosses. We had to secure water based craft paint from Michaels or Hobby Lobby. Normal spray paint will eat through and dissolve foam.

We drove a wooden stake 18″ up the center of the main foam block and cross braced it onto the 2′ wooden bases. These were painted flat black and could be screwed directly into the stage decks, securing the crosses from tipping over. While the final pieces would be extremely light the last thing we want on Easter is a falling cross.

In the end we had produced a trio of tree brown crosses, textured and shaped to be as close to wood as possible with our skills and timetable.