The Arado Ar 68 was a German single-seat biplane fighter developed in the mid-1930s. It was among the first fighters produced when Germany abandoned the restrictions of the Treaty of Versailles and began rearming.

Design and development

Designed to replace the Heinkel He 51, the Ar 68 proved to have admirable handling characteristics on its first flight in early 1934, despite Arado's inability to secure a sufficiently powerful engine for the prototype. Eventually, a Junkers Jumo 210 was installed and the Ar 68 went into production, though not before worries about the unforgiving nature of such a high-performance aircraft almost resulted in the cancellation of the project.

The Ar 68 entered service with the Luftwaffe in 1936 and one of the first units was stationed in East Prussia. Soon, the fighter was sent to fight in the Spanish Civil War, where it was outclassed by the Soviet Polikarpov I-16. Arado responded by upgrading the engine of the Ar 68E, which soon became the Luftwaffe's most widely used fighter in 1937–38, before being replaced by the Messerschmitt Bf 109. The last Ar 68s served as night fighters up to the winter of 1939–40, after which they served as fighter-trainers until 1944.

Ar 68V1: Prototype, powered by a 492 kW (660 hp) BMW VI engine. First flight in 1934.
Ar 68a: First prototype. 1 x 478 kW (641 hp) BMW VId V-12.
Ar 68b: Second prototype. 1 x 455 kW (610 hp) Jumo 210A inverted V-12.
Ar 68c: Third prototype. 1 x 455 kW (610 hp) Jumo 210A inverted V-12.
Ar 68d: Fourth prototype. 1 x 478 kW (641 hp) BMW VId V-12.
Ar 68 V4: The fourth prototype (Ar 68d), redesignated after the RLM (Reichs Luftfahrtministerium) introduced the standardised Versuchs (research) number system.
Ar 68e: Fifth prototype. 1 x 507 kW (680 hp) Jumo 210Da inverted V-12.
Ar 68 V5: The fifth prototype (Ar 68e), redesignated after the RLM introduced the standardised Versuchs (research) number system.
Ar 68E: First type to enter Luftwaffe service, powered by a 455 kW (610 hp) Junkers Jumo 210, at sea level for 5 minutes, 500 kW (671 hp) at 3,800 m (12,467 ft).
Ar 68F: Interim production, powered by a BMW VI 7.3Z; 559 kW (750 hp) at sea level for 1 minute, 410 kW (550 hp) at 1,000 m (3,281 ft), awaiting supply of Jumo 210 engines.
Ar 68G: Abortive attempt to fit a supercharged 500 kW (671 hp) BMW VI.
Ar 68H: Only a single prototype was built, powered by a 634 kW (850 hp) BMW 132Da 9-cyl. supercharged air-cooled radial. It was also the first Arado fighter to have an enclosed cockpit.

Operators

 Germany: Luftwaffe

 Spain: Spanish Air Force