Junkers A20 Mailplane 1:48 byContour Creative

[papermodelfan]

Another in the series of "Golden Age" commercial aircraft, this one the Junkers A20 two seater mailplane from 1923. The aircraft looks like a civilian spin off of the WW1 Junkers monoplane fighter design, and a precursor to the F13 airliner. Built of corrugated sheet metal, it looks rugged and sturdy.

The model itself is also rugged and sturdy, with CC's unique design approach. Three layers form the fuselage and wing. The fit is excellent throughout, thought one does need to be cut and shape a number of parts to fit by eye. (The cardstock I am using is leftover from Xmas Card production a few years ago, so random text and images appear on the backside)

I started with the long and thick wing. The three parts, center and outer panels, are first joined with little strips along the bottom, then reinforced with a second internal flat piece, and then with a piece of heavy card. Part of the key to the shape is scoring on the underside at the break point where the leading edge starts to curve up. I did this on the inside, so there is not a visible score mark. The spar is glued in by eye, and the ribs are cut to fit the spar by eye. Then the top surfaces are curved and glued down, incorporating a slight dihedral in the bottom surface.

[papermodelfan]

The ailerons and tail surfaces are formed around an inner cardboard core. Carving and shaping the trailing edge of the core is key - in retrospect, it might be even better to shape the entire core to an aerodynamical curve. For the underside of the rudder, an edge strip seemed to be necessary. There is lots of spare colored paper to work with.

[papermodelfan]

The fuselage is also built with several layers - the outer skin, a white middle stiffener with tabs on it, and the inner skin that has the cockpit walls printed on it. The instructions say to cut out the white bars in the inner skin for the cockpit formers, but I could not figure our how to do this and then get the resulting pieces of the skin to be in the correct position. Instead, I sanded down the cockpit formers a bit to avoid making the fuselage a too wide. Note that there is even an inner skin on the underside of the top of the fuselage. The rear of the topside turtleback gets a second covering, so the line down the middle disappears.

[papermodelfan]

The cockpit interior is simple, but adequate for what is visible through the two openings. the instructions suggest gluing the formers in place, and then placing the floor up into the model. I chose to build the interior as a unit, and then place it as a unit into the fuselage. I also doubled the cockpit coamings - wonder what those were actually made of? maybe leather?

A smaller former is glued into the aft fuselage, where ever it seems to best fit.

[papermodelfan]

One real challenge was the rear fuselage's bottom surface. This is designed as four panels that fold in from the outer edges, that meet in the middle. However, by this time I had closed up the top turtleback, and could not figure out how to get access to the inside of the lower fuselage to glue that securely. I suppose if I had done this step first, before closing the top it would not have been an issue. My alternative was to print a second set of the bottom flaps, glue them together, and then glue this panel in place, and trimming it to shape along the edges.

[papermodelfan]

Landing gear is built on a wire frame (joined with superglue). The main legs are wrapped in paper, then in a shock absorber with cardboard stiffeners, and set into collars on the undersurface of the wing. The motor is very simple, with only the 6 cylinder heads showing. I used three ply cardboard for the radiator - note the undersurface is cut at an angle to fit the fuselage angle.

[papermodelfan]

A few more details - handles, prop, pilots boarding step (from basswood) etc., and it is finished. A very clean design, and a pleasure to build.

Thanks to Rosie and Terry of byairclassique.com for the model, and to
ecardmodels for making it available.

[MacSongLi]

Fantastic job, extremely detailed, clean build (including a perfect job on the propeller). I love the end result.

Gary

[Don Boose]

Rob - You are really doing great work on the Golden Age aircraft from Rosie and Terry. I hope you will bring them to Sterling in October so we can get a good close-up look at them. Don

[gregbal]

Really stunning build. A beautiful bird.