C.Jerzy Polish Aircraft 1893-1939 (Putnam)
Autobiplan Warchalowski System Type XI. In the autumn of 1911 Adolf Warchalowski conceived a design for a seaplane to a requirement of the Austrian Naval Command. Construction of the single example of this floatplane (Type XI) began in November of the same year and the machine was finished just in time to be shown at the IFA (International Aviation Exhibition), which was staged in Vienna from 18 May to 23 June, 1912. Displayed in the centre of the exhibition hall on a specially provided pool, the floatplane stole the show, and another Warchalowski Autobiplan, the Hieronimus-powered military biplane, presumably Type IX, displayed with it, also received a fair share of attention.
The Type XI Hew for the first time on 25 July, 1912, from Wiener-Neustadt airfield with Adolf Warchalowski at the controls, its floats being provided with wheels for the flight trials, and two days later it made its first flights with passengers. On 7 August, in the course of the official acceptance trials, the Type XI took-off with the maximum specified load of 260 kg (573 lb), comprising a pilot, observer, fuel and sand ballast, and stayed in the air for 30 min at a height of200 m (656 ft). On 10 August the machine, carrying the same load, took-off in less than 150 m (492 ft), half of the specified distance, and during the speed test recorded an average speed of 70 km/h (43.5 mph). Later the same day the aircraft made a duration flight of 1 hr 3 min during which it climbed to 700 m (2,296 ft). After completing all its trials with flying colours the Type XI was delivered to the naval base at Pola, becoming the second seaplane to go into service with the Austrian Navy.
The Type XI was the last aircraft to be developed by Adolf Warchalowski. Early in 1912 the Austrian authorities decided to convert Wiener-Neustadt aerodrome into a military aviation centre after which civilians were to be excluded. On 21 March, 1912, Adolf Warchalowski, who, as a Pole, was presumably regarded as a potential security risk, announced his intention of leaving the Autoplan-Werke after completion of the Type XI seaplane and of establishing a factory for agricultural machinery in partnership with his brother Jozef. Several weeks earlier the design work on a new biplane, begun to meet an Austrian War Office specification for a 'Normal-type' (Standard-type) military aircraft, which had been issued in December 1911, passed from Adolf Warchalowski to Josef Sablatnig (this machine, known as the Sablatnig Military Biplane, making its first flight on 1 May, 1912). Autoplan-Werke, which had to vacate their Wiener-Neustadt premises, intended to move to a civil airfield, but this plan was eventually abandoned and in September 1912 the firm merged with Etrich and Lohner to form one large concern, which began the development and quantity production of military aircraft to Austrian Government contracts.
Construction: The Autobiplan Warchalowski System Type XI was a two-seat open-frame unequal-span twin-float naval biplane of composite construction. The wings, fabric-covered two-spar wooden structures with a total gross area of 48 sq m (516.7 sq ft), comprised a wide centre section and single-bay outer sections, the outer panels of the lower wing being set at a pronounced dihedral angle. The crew nacelle, housing an engine in front and side-by-side seats for a pilot and observer behind, was attached under the lower wing in order to bring the C.G. as close to the waterline as possible. The open-type rear fuselage frame carried the tail unit, which was of monoplane type and consisted of a single rudder, tailplane, and elevator. The float gear comprised two main flat-bottomed wooden floats, which were carried on a metal-tube framework, and a small single float under the tail. Power was supplied by one 85-90 hp Werner & Pfleiderer Hieronimus four-cylinder inline water-cooled engine, installed in the nose of the nacelle and offset to starboard, which drove a two-blade pusher airscrew through a system of transmission shafts and gears. Overall dimensions included a span of 15 m (49 ft 2 3/4 in) and a length of 10 m (32 ft 9 3/4 in). Empty and maximum loaded weights were 650 kg (1,433 lb) and 910 kg (2,006 lb).