ARADO AR.396
CL MODEL EMPLOYS CARDBOARD CONSTRUCTION TECHNIQUES
BY CHUCK FELTON
SPECIFICATIONS
- Type: C/L scale (control-line)
- Wingspan: 60 inches
- Length: 49 inches
- Wing area: 541 square inches
- Weight: 74 ounces (fully fueled)
- Wing loading: 19.7 ounces per square foot
- Power system: .40- to .50-size glow motor or equivalent
- Construction: Primarily 1/8-inch corrugated cardboard
The Arado Ar.96 was a low-wing, single-engine aircraft of metal construction that became the Luftwaffe’s standard advanced trainer during World War II. As the war progressed, a redesign was undertaken to save metal. The result was the Arado Ar.396, constructed primarily from wood.
These aircraft were to be built in factories in occupied France, but the course of the war made that impossible and production was moved to Czechoslovakia. Only a few aircraft were built by war’s end and none were pressed into service. After the war, roughly 200 aircraft were built in France by the SIPA company and used for training and as counterinsurgency aircraft in North Africa. Those aircraft were fitted with wing racks for carrying light bombs and rockets.
The Arado Ar.396 model presented here is simple in construction and inexpensive. It uses 1/8-inch corrugated cardboard as the primary building material, which greatly reduces building time and cost. The design makes use of cardboard’s unique features: it can be used in large sections and folded. Each wing panel is built from a single piece of cardboard scored and folded at the leading edge (LE) with cardboard ribs and a single spar.
The tail surfaces and fuselage are primarily cardboard with little internal bracing required. The result is a low-cost, fast-building model that has a good, scale-like appearance and can take plenty of punishment at the flying field.
Cardboard varies in weight, but any 1/8-inch corrugated cardboard will do. Sources of this material include box manufacturers and local shopping centers where you can find stacks of discarded boxes.
CONSTRUCTION TIPS
- Adhesive: Use water-based glue such as white glue or Titebond. Contact cement is not recommended because parts cannot be shifted once glued.
- Folding: Score fold lines with a screening tool (available at hardware stores). The tool is a handle with about a 1-1/2-inch-radius wheel that is run along a metal straightedge on the fold line.
- Finishing: Cardboard provides a solid, nonporous surface. The easiest method is two coats of clear dope, sanding lightly between coats with 400-grit sandpaper, followed by two coats of colored dope.
- Coverings: Solarfilm, MonoKote, or vinyl paper can be used. If using these coverings, avoid doping the surface first to ensure a better bond.
- Paper tape: Cover all seams, joints, and exposed edges with gummed paper tape (1-inch-wide roll from a stationery store). Cut to length, dip in water, and smooth over the seam.
- Cutting and grain: Note the direction of the corrugations when cutting parts. Score and fold parts as indicated on the plans.
CONSTRUCTION DETAILS
- Empennage: The stabilizer and elevator leading edges are capped with 1/8- by 1/4-inch balsa strips and rounded off. The elevator is joined to the stabilizer with flexible nylon hinges in four locations.
- Wings: The top wing surfaces are folded down and glued in place. A balsa wingtip is shaped from 1/2-inch sheet with a 1/8-inch plywood wing-line guide. Paper tape covers the seam between the balsa wingtip and the cardboard wing.
- Spar and ribs: The spar is glued to the bottom center section and cardboard ribs are added. Note the 1/8-inch plywood spar joiners at the dihedral breaks and plywood gear-mount inserts.
- Fuselage: Flat fuselage sides are lined with balsa strips recessed 1/8 inch and have cardboard supports for the bellcrank and plywood fuel-tank mounts. There are cutouts for flying wires. The forward bottom section has formers and a centerline balsa stringer ready for deck covering; additional cutouts help reduce weight.
- Pushrod and assembly: The pushrod is made from 1/4-inch-square spruce. Uneven seams are later cleaned up with strips of gummed paper tape.
Look for cardboard with brown paper on one side and white-finished Kraft paper on the other side. Using the white paper on the outside of the model yields a smooth finish and neat appearance. The folding method and use of gummed paper tape to seal joints and exposed corrugation are explained in the construction hints.
The model’s bottom airfoil is flat with a curved upper surface created by the scoring and folding technique.
A .40- to .50-size engine can be used. The author’s model is powered by a .40 engine and has a fully fueled flying weight of 74 ounces. With a 541-square-inch wing area, this produces a wing loading of 19.7 ounces per square foot.
The accompanying pictures in the original article describe the build.
—Chuck Felton
SOURCES:
- AMA Plans Service
(800) 435-9262, ext. 507 www.modelaircraft.org/plans.aspx
- Chuck Felton's website
Transcribed from original scans by AI. Minor OCR errors may remain.
