A 1/2-scale Demoiselle

Model Airplane News, Jun 2000 by Nelson, Jerry

Jorg Vogelsang of Hagen, Germany, is a very wellknown giant scale modeler. He is recognized both for his master modeling talents and for the unusual subjects he selects. His efforts have included a 1/2-scale WW I fighter and a twin-turbine-- powered WW II Messerschmitt 328. Jorg's most recent project is a 1/2-scale Santos DuMont 1908 Demoiselle 21 which, to the delight of everyone, he demonstrated at the annual Quarter Scale Aircraft Association fly-in in Las Vegas.

You might recognize this aircraft as being the one featured in the motion picture "Those Magnificent Men in their Flying Machines," but more impressive is that the Demoiselle 21 was Europe's first successful 3-axis-- control (pitch, roll and yaw) aircraft. Its wing was rigged to twist or warp to provide roll (aileron) control, and the entire tail group was rigged to move as a single unit-no separate rudder or elevator surfaces. Jorg's model is a faithful reproduction of the full-size aircraft, and it features the same type of control setup.

The model was also built using materials similar to those of the full-size Demoiselle; it has bamboo fuselage longerons wrapped with twine in several locations to prevent them from splitting. The highly undercambered wing ribs are made of spruce, and the varnished Dacron fabric is laced onto each rib. The large spoked wheels are homemade. Jorg is an excellent machinist; he designs and builds the engines he uses to power his models; the Demoiselle powerplant is no exception. The 4-stroke, twin-cylinder, horizontally opposed engine has a 277cc displacement and utilizes a wet sump-oil system

(the oil is not mixed with the fuel). The engine is energized with a ProSpark* electronic ignition system and turns a 39x12 wooden prop at 3,200rpm.

The flight characteristics of this huge model are impressive. Flight speed at 1/3 throttle is approximately 5mph, and takeoff runs are only 20 feet long. At low-rpm cruise speed, the model appears to be very coordinated in the turns; there is hardly any engine noise. Despite its unusual tail-group control setup, and its having only a fixed tailskid, the model is very well behaved on the ground.

Of all the projects Jorg has brought to the QSAA meet, the beautifully crafted Demoiselle is my favorite.