FVA 9 - Blaue Maus II

In 1933, the FVA finally started to design its own glider again (not counting Hermann Mayer’s aircraft). In addition to the success of Mayer’s gliders, the incentive to develop a glider specially designed for cross-country flight from upwind to upwind was decisive for this. Hans Sander, together with Karl Doetsch, therefore designed a light thermal glider in which emphasis was placed not only on the lowest possible sink rate, but also on good high-speed performance and characteristics. Today this requirement is taken for granted, but at that time thermal flying was still in its infancy and theories for optimizing cross-country flight were still being formulated very tentatively.

The choice of the name “Blue Mouse II” was intended to document that the FVA was willing to continue the outstanding gliding successes of the founding period and to build a similarly successful performance glider adapted to the advanced development. The FVA-9 designers Sander and Doetsch deserve the credit for having reawakened the FVA’s willingness to develop its own aircraft after many years of purely aeronautical activity, thus giving the “F” in the club’s abbreviation its original meaning again.

The FVA wrote in “Flugsport” 1934, No. 23 about the FVA-9 “Blaue Maus II”:

“Thermal glider FVA-9 “Blaue Maus 2″”.

The FVA-9 is intended by Akaflieg Aachen as a pure thermal glider. The local conditions allow slope gliding only to a limited extent - the terrain near Orsbach is unfortunately not high enough to reach cloud connection from there, despite all other advantages - and so the necessity arose for us to create a glider for thermal flight from preceding aerotow. Therefore, during construction, special emphasis was placed on good maneuverability, fast and slow flight, and low weight.

The wing is of single spar design, the nose is planked with diagonal plywood. The ribs were tested by thorough strength tests. Later, during construction, great care was taken to adhere exactly to the prescribed dimensions, and the weight calculated in this way was even slightly undercut.

The fuselage outline was developed from a purely functional point of view and then tested on the model in the wind tunnel for its aerodynamic usability.

According to the results of the measurements, the first design was modified. The fuselage tapers off into a torque tube. The last two edges of the fuselage are also the main spars of the keel fin. The tailplane is self-supporting and rests on a superstructure which grows organically out of the fuselage. The fittings are bent and welded from sheet steel. The rudders are mounted in self-aligning ball bearings. This design has proven itself. The rudders are operated by control cables, the ailerons by pushrods and control cables.

The design and tests were carried out during the winter months, and construction began at the end of April. It presented no particular difficulties as a result of the most careful design work and sufficient drawing material.

The wings were built on a slipway for vertical wing construction, and a special slipway was built for the fuselage. The ailerons were not built on the wing, but by themselves. For planking, the use of nailing strips was avoided as much as possible, and instead tensioning straps were used, whose uses on the fuselage are also very versatile. The aircraft was completed in mid-July and tested during the Rhön competition. Of its flight characteristics, the good sensitivity of all rudders deserves special mention.”