Musger MG 12a (oz15007)

About this Plan

1938 Musger MG 12a. Radio control scale model glider. Wingspan 2750 mm, scale is 1/4.

Quote (google-translated from the Italian): "MG12a-INTRODUCTION: The history of the glider: After the two-seat performance gliders MG9 and MG9a, engineer Erwin Musger designed the MG12, a single-seat school and training glider for Austrian flying clubs. The prototype of the MG12, called OE-Primus, was built in 1937. The fuselage, with a hexagonal section, was provided with a solid keel that supported the skid mounted on rubber shock absorbers. The pilot was sitting under the wing, at the center of gravity, and access was not easy, disturbed by two struts that reinforced the front part of the cantilevered wing on the cabana. The V-shaped struts were made of profiled steel tubes.

Since the rear part of the fuselage was very lightly constructed, two triangulation cables connected to the wings strengthened the assembly. The wingspan was 12 meters, the wings had a positive sweep of 5° and the chord was constant up to the middle of the ailerons. The stabilizer also had a strong rear sweep and the drift was aerodynamically compensated.

The MG12a prototype was built in January 1938 and called « Ameise » (ant). It was the evolution of the predecessor MG12 with numerous improvements: the entire front part was open and free from pillars to facilitate access for the pilot and a small windshield was installed to protect him. The wing struts were now made of profiled wood. The fuselage had been lengthened by 19 cm and entirely covered in plywood. The wingspan had been reduced to 11.58 m, but the surface area remained the same. The same positive arrow was retained, but the constant chord stopped at the ailerons, which then protruded slightly with a rounded shape and were shortened by 50 cm. The deflection of the stabilizer was smaller and its surface area slightly increased. The structure had been reinforced and the stabilizer no longer had lower struts. Only 15 examples were built.

The genesis of the model: To continue in the Musger saga, after the MG19b and the MG9a, I decided to also build the MG12a. After this I promise to stop, even if there are still about twenty to reproduce, some of which impressed me a lot, such as the MG II Uhu.

I wanted a small glider, approximately 1:4 scale and with a reasonable weight to be able to launch it alone on a slope. The full-size MG12a had just 12 meters of wingspan and a large wing chord, and that's exactly why I decided on it. Musgers are rather rare historical gliders: apart from a few MG19s that still fly, they are rarely if ever reproduced as models. The MG12a is a high cabana wing with an original shape, but Musger's signature can be recognized in the empennage with the typical round fin.

To make progress in construction techniques I wanted to get as close as possible to what was being done on the full-size and for this reason I decided to create a model without balsa, entirely in pine and plywood, with ribs and frames entirely in the structure, as well as the spars.

The construction drawing: The drawing has been reduced to 1/3 in order to be able to publish it as an attached table. You will then have to cut it horizontally along the line where the scissors are drawn, and you will obtain four drawings to enlarge by 300%. You can check the accuracy with the sample scale which must be 200 mm. Those who want to build the model, but who are hesitant to embark on a construction with ribs and frame frames, can build traditional pins using 3 mm plywood for the frames and 3 mm balsa for the ribs.

If someone then wanted to build a mini reproduction while maintaining the scale of the attached drawing, then they would do well to opt for a thinner and flatter profile to facilitate construction (such as the E205) and create a model entirely in balsa..."

Direct submission to Outerzone.

Note see also the original build thread on Retroplane site at: http://www.retroplane.net/mg12a-maquette/page1.htm for more details and lots of excellent pics.

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