Aviation of World War II
FW 56 Stößer
Fw.56 "Sparrowhawk" ("Stößer"). Kurt Tank's first job as CTO at Focke-Wulf. The aircraft was developed as a training aircraft for advanced flight training, it was also envisaged to use it as an air defense fighter ("home defense fighter").
Constructional diagram - parasol, with plumage from "Albatross". The stabilizer and elevator were in front of the rudder, all rudders were of wood construction with fabric sheathing. Particular attention was paid to aerodynamics, which made it possible to obtain good flight data at low engine power. Chassis with two cantilever struts with oil damping, with wheels on low pressure pneumatics.
The aircraft demonstrated excellent climb rate and high aerobatic qualities, participating in demonstration performances. In 1935 the Stößer was put into production under the designation Fw.56a-1. It was a very obedient aircraft. On it, every future fighter pilot could check his worth. Once having mastered it, the pilots spoke of the "Stösser" as an excellent aircraft.
"Stoessers" throughout the war were used in NSFK *, aviation schools, participated in research programs.
The exact number of aircraft built is unknown, it is believed that 900-1000 aircraft were built.
* approx. NSFK - National Socialist Air Corps (German Nationalsozialistisches Fliegerkorps) - a paramilitary organization of Nazi Germany
Armament. One or two 7.92 mm machine guns MG-17 with 250 rounds per barrel; 3 × 10 kg bombs.
Fw.159 was designed for the new Junkers engine - Jumo-210 - 12-cylinder inverted V type, liquid-cooled. The choice of motor was due to the task. The fuselage is an oval monocoque section made of light alloy. The all-metal wing is rectangular in shape. The wing design included the main and auxiliary spars; flaps and ailerons were attached to the latter, occupying the entire trailing edge of the wing. NASA wing profile, relatively thin. The strut went from the main spar of the wing to the fuselage. The pilot was located under the rear sliding canopy. All fuel was housed in a single tank under the cockpit that could be jettisoned. Particular attention was paid to the ease of maintenance of the aircraft - almost the entire forward fuselage had removable panels providing quick access to the engine, weapons and auxiliary equipment.
The Fw.159-V1 was equipped with a Jumo-210A engine with a takeoff power of 610 hp. and a wooden two-blade fixed-pitch propeller "Schwarz".
A feature of the Fw.159 was the retractable landing gear, or rather the mechanism for their removal, which turned out to be the Achilles' heel of the fighter. In the very first test flight under the control of the flag captain Wolfgang Stein, the main landing gear did not lock into the released position. After an hour and a half of flight, after running out of fuel, immediately after touchdown, the landing gear was demolished. The plane rolled over a couple of times, while it was damaged and could not be restored. As a result, the Fw.159-V1 had to be written off, and Stein miraculously escaped with only bruises.
Subsequently, it became clear that the engineers who designed the chassis did not include air pressure in the calculation, and the hydraulic power was clearly not enough to release the racks into the stream. As a result, the second experimental Fw.159-V2 (D-INGA), completed shortly after the accident, received more powerful chassis hydraulics. The tail strut was lengthened, and the fairing on it was removed. The controllability of the Fw.159 differed little from the "Shtesser", but the speed and rate of climb were clearly below the calculated ones, and the turn time was too long.
The third experimental V3 (D-IUPY) featured a Jumo-210V engine with a takeoff power of 600hp and 640hp at 2700 m. The cockpit canopy was redesigned - the movable part consisted of three panels, and the fairing behind the movable part, which was previously integral with the latter, became fixed. It was armed with two MG-17 machine guns with 500 rounds per barrel. The machine guns were synchronized to fire through the propeller. It was planned to install the MGFF gun for firing through the propeller hub, although the gun was not installed (it was not very suitable for installation in the collapse of the cylinders due to overheating).
During 1936, the Fw.159-V2 was also equipped with two machine guns, the fairing behind the canopy became fixed. The lantern, consisting of two panels, moved over the fairing. The three-bladed fixed-pitch propeller was replaced with a two-bladed Junkers-Hamilton variable-pitch propeller. A Jumo-210Da engine was installed with a two-speed supercharger with a power of 680 hp on takeoff and 670 hp at an altitude of 3900 m for 5 minutes. V3 also received a two-bladed variable pitch propeller. At the same time, a Jumo-210D with a take-off power of 700hp and 730hp at an altitude of 1000 m was installed on it. But by this time (late summer 1937), the Ministry of Aviation had already relied on Bf.109. Fw.159-V2 and V3 were tested in Travemünde during the spring and early summer of 1936, but the Luftwaffe's preference for a cantilever monoplane manifested itself even at the beginning of work and intensified even more after testing the Bf.109 and He.112. The Focke-Wulf fighter was no longer considered a serious contender and was perceived by the test center personnel as a kind of palliative between outgoing biplanes and more aerodynamically advanced monoplanes, moreover, lacking the maneuverability of the former and the speed qualities of the latter.
The Fw.159 had really few advantages. In the version tested in Travemünde, it was slightly lighter than the He.112 with the same engine, and even had a significantly higher wing load, which (111.5 kg / m²) was only slightly less than that of the lighter (for 300 kg) Bf.109 with Jumo-210 engine. Despite the significant efforts of Blaser and his designers to reduce the air resistance of the fighter, the latter clearly could not compete with the Heinkel and Bayerische Flygzeugwerke aircraft, inferior in almost all characteristics. In addition, the complex design of the landing gear cleaning mechanism would hardly have been joyfully accepted by the service personnel.
Although the Fw.159 no longer participated in the competition, its testing and refinement continued until 1938. With the Jumo-210D direct injection engine, it was able to reach a speed of 403 km / h at an altitude of 4500 m. to debug and the test program was interrupted by constant emergency landings.