Graubele 3 (oz12356)

About this Plan

Graubele 3. Free flight glider model. Wingspan 2080 mm.

There were two versions of the Graubele 3 plan, with different wing designs: curved dihedral, and polyhedral.

Note plan shows parts at full size, with general layout at 1:2.5 scale.

Direct submission to Outerzone.

Update 12/8/2026: Added (later) article from FMT 1/1994, thanks to Axel_VPF.

Quote (google-translated): "Flying History: The Vintage Model Graubele, from 1937.

What would drive a 29-year-old to build a vintage model aircraft? Well, over half a century of model-building history provided the inspiration for me to build a vintage model and equip it with radio control. I chose the Graubele 3, a model developed by Johannes Graupner in 1937 that helped put the company on the map. It was love at first sight. Having grown weary of plastic model kits, I found inspiration in the classic philosophy of model building, working from old plans using pine strips, plywood, balsa wood, and tissue paper and drafting card for the covering.

I ordered the plans for the Graubele 3 through the Antikmodellflugfreunde Deutschlands (German Vintage Model Aircraft Enthusiasts). After compiling the parts list and gathering all the materials, I could hardly wait to get started.

The building process was different from what I was used to: tracing and sawing out ribs and formers, covering with tissue paper, and planking with drafting card - it was all quite labor-intensive. Yet, it was also great fun watching the airframe take shape, piece by piece took shape and grew into a beautiful wooden structure.

Since the model was originally designed for free flight, some modifications had to be made. The most important change for me was the airfoil; the original design featured a 15% thickness and significant camber. That thick airfoil was intended for free flight to allow for slow flying speeds.

For an RC model—with its higher wing loading and the need for a wider speed range—the original airfoil would have created too much drag. I chose the Eppler 193 airfoil as an alternative, a decision that later proved to be the right one.

To protect the radio equipment and improve handling, I planked the fuselage sides - from the nose back to the wing's trailing edge - with 0.8 mm birch plywood.

The horizontal stabilizer was originally a fixed, glued assembly; I redesigned it as an all-moving tailplane (pendulum elevator) to avoid spoiling the original look by splitting it into a fixed fin and a movable rudder.

The wing, with a span of 2.18 m, was designed to be detachable; this facilitates transport and allows for the mounting of an electric motor pod between the wing halves.

Planking the leading edge from spar to spar with 240 g/m² drafting paper ensures that the wings are sufficiently rigid for the RC version of the model. The rest of the model was covered with tissue paper to preserve its vintage appearance. I coated all un-covered wooden parts with a clear synthetic resin finish, which enhanced the visibility of the wood grain. The covered sections were treated only with thinned dope..."

Supplementary file notes

Article (FMT 1994)

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction