Andreasson BA-6 (oz2481)

About this Plan

Andreasson BA-6. Scale model for control line of the Swedish light plane.

Direct submission to Outerzone.

Update 23/03/2021: Replaced this plan with a clearer copy, thanks to dfritzke. Note this is scanned from fullsize, and includes full build notes not included in the printed article.

Quote: "ANDREASSON BA-6. Designer-okayed Control Liner, modeled by Walt Mooney.

Bjorn Andreasson, a noted Swedish aeronautical engineer, has designed seven outstanding light airplanes. His seventh, the BA-7, evolved in San Diego while he was a Convair engineer, has been described and modeled in a past American Modeler. The BA-6 was built in Sweden. It is an all-wood, fabric covered, low wing, single place, fully acrobatic lightplane, extremely well liked by those who have flown it. Several examples are currently in construction in the United States.

BA-6 has a pleasing shape, suitable for a simple U-control scale model. Particular characteristics that make for a good Ukie are the large, rather low aspect ratio, wing, the straight through elevator aft of the rudder, the simple Cessna type spring leaf landing gear, and the slab sided, flat bottomed fuselage.

The model BA-6 is exact scale as to shape and size with no deviations. In addition construction follows the original wherever possible with all surface textures correct (wood surfaces, fabric surfaces, metal surfaces.)

All bulkheads and formers in the model are in the correct location, the fuselage sides, bottom, top, and turtle deck follow the full scale construction. The wing has the correct number of ribs and is planked like the original. Only the tail, the flans, and the ailerons deviate from scale construction. They are carved fom solid balsa; however, scale surface textures are simulated. The metal cowl is simulated by highly finished Fibreglas on the model.

Bjorn Andreasson has returned to Sweden to produce his BA-7 but while he was in San Diego he checked the accuracy of our model plans. After several minor changes (a relatively meagre first three view was used to make the original layout), he certified that the model is an accurate copy of the full sized ship and signed the plans with a statement to that effect.

The model has .several features which should be noted. The direction of the flight circle is clockwise, contrary to most U-controls, to help keep the lines tight. This I feel is important for 1A U-controls because of their small size. In addition the U-control bellcrank is located in the wing to put it below the model's center-of-gravity and help hold the model out at the end of the lines by providing an outward banking moment.

It will be noted that the model in the photographs has a non-scale color scheme. I felt that since it is a home built type, any color scheme is okay, and the license number (SE-XEY) was for kicks. Zip-a-tone was used on the plans (dotted areas) to indicate the scale color scheme for SE-BXX. Blue on white were the colors. The circle just above the C.G. on the side view had a white "BAG" in it which is not shown on the plans. The wing walk is black anti-skid surface.

I had no accurate cockpit interior data except for the canopy hinge location, and baggage door in former 3. The instrument panel has scale instruments in a reasonable arrangement. The upper half of former 4 has been made solid but if the baggage door is made to open, former 4 should be open similar to former 5 as indicated by the phantom line. The real plane can stow skis in its baggage compartment. No seats or controls are shown, but a semi-scale simulation can be made if desired. The airplane was equipped with a stick and rudder pedals and the seats were simply cushions on the wing upper surface and against bulkhead 3.

If you're interested in building a simple, accurate, nice flying, scale U-control model for an .049 engine our BA-6 is a good choice.

Pick out quality balsa wood for this model since weight and strength are important. Medium balsa is used everywhere on the original but a little ballast was required to get the CG far enough forward; so I suggest, light weight wood for the horizontal and vertical tail pieces. I like to cut out all the parts before starting assembly. So in the following instructions we'll assume all the ribs, bulkheads, etc, are already cut out.

The wing is a conventional structure with a leading edge, ribs, top and bottom spar, and trailing edge. It is sheet covered all over the top and halfway on the bottom. Build the center section first by pinning the trailing edge and bottom spar to the work board and cementing the ribs as required. Then add the leading edge. When this is done, prop up one end 2-5/8 in and build one outer panel in place. I used a laminated trailing edge and lapped the outer panel laminations with the center panel lamination. Then when the first outer panel is dry, raise the other end of the center panel 2-5/8 in and build the opposite tip. Now add the top spar. Carve the leading and trailing edges to the shape shown in the rib sections.

Before cementing the top and bottom sheeting to the wing, install the two pieces of plywood to hold the control bellcrank. Both bottom and top spars are continuous across the center section until after the plywood installation. They are then cut away at a taper to clear the bellcrank bolt head and nut as shown on the drawing just above Andreasson's certification note. Also install the aluminum tube lead-outs and the leadout wires. Take a piece of .060 music wire about 12 inches long and bend it to fit the bellcrank for the pushrod. Now install the wing sheeting. Making a careful fitting job at the dihedral joint, around the leadou,ts, and at the trailing edge. Trim the covering flush at the end rib and add the wing tip blocks.

Now carve the flaps, and ailerons to the shape shown in the rib sections and carve the tips to their final shape. Hinge the ailerons and flaps to the wing with thin aluminum strips (or tin can stock) as shown on the plans.

Carve the tailpieces from solid sheet balsa to the shape and sections shown. The rudder is hinged to the fin with aluminum strips. I used Sullivan Nylon U-control hinges for the elevator-to-stabilizer attachment. They have a slight springiness which tends to give neutral elevator with slack lines which can be an aid with U-controls. Cloth hinges must be avoided because they will ruin the scale surface texture. Make up an elevator control horn from tin can stock. Force the point into the elevator and cement firmly in place. Sandpaper the tin can stock to give a good surface for cement bonding.

Laminate the fuselage sides and doublers. Note the doublers run from the back side of former 1 to the forward side of former 3. When this is thoroughly dry start fuselage assembly by installing formers 1 and 3. Make sure they are square with the sides and allow to dry. Then add the rest of the formers, the bottom and top covering. Now add the upper parts...

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