Avis I

In 1931 the Central Repair Workshops located in Székesfehérvár-Sóstó started to build the AVIS (Anderlik-Varga-Iskola-Sport) airplane which apparently looked like a sports and single-seat trainer airplane.
In fact, it was a fighter airplane intended to be used by the Légüyi Hivatal (Aviation Department) which was the clandestine Hungarian Air Force.

It was an all-metal, single-bay staggered biplane designed by the prof. Elöd Abody-Anderlik, László Varga, István Liszt and Deszö Fridrik. The first airplane was completed and flown in 1933 and was powered by a 420hp Manfred-Weiss-built Jupiter VI engine. The expected armament were two synchronised 7.62 Gebauer machine-guns. This airplane proved to be seriously underpowered, which lead to the development of the AVIS II. The only prototype was assigned to the flying school at Szombathely where it served until 1936.

Sources:
1. Salamander Books - The Complete Book of Fighters
2. http://www.aviastar.org/air/hungary/avis-1.php