Arado Ar 68

The Arado Ar 68 was a 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.

Ar 68a

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. 

Ar 68e 

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.

                                                    Ar 68c

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 1937-8 before being replaced by the Messerschmitt Bf 109. The last Ar 68s served as night fighters and fighter-trainers up to the winter of 1939-40.
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General characteristics: Arado Ar 68F-1
Crew: 1
Length: 9.5 m 
Wingspan: 11 m 
Height: 3.3 m 
Empty weight: 1,600 kg 
Ar 68F-1 1,520 kg 
Gross weight: 2,020 kg 
(Ar 68F-1 1,950 kg 
Powerplant: 1 × Junkers Jumo 210Ea inverted V-12 liquid-cooled piston engine, 507 kW (680 hp) at sea level for 5 minutes, 500 kW (671 hp) at 3,800 m 
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(Ar 68a 1 x 478 kW (641 hp)) BMW VId V-12.)
(Ar 68b 1 x 455 kW (610 hp)) Jumo 210A inverted V-12.)
(Ar 68c 1 x 455 kW (610 hp)) Jumo 210A inverted V-12.)
(Ar 68d 1 x 478 kW (641 hp)) BMW VId V-12.)
(Ar 68e 1 x 507 kW (680 hp)) Jumo 210Da inverted V-12.)
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Ar 68F-1 
BMW VI 7.3Z 559 kW (750 hp)) at sea level for 1 minute, 410 kW (550 hp)) at 1,000 m.

Ar 68H 1 x 634 kW (850 hp)) BMW 132Da 9-cyl. radial.
Performance
Maximum speed: 306 km/h; 165 kn (190 mph) at sea level (Ar 68F-1 330 km/h)
335 km/h (208 mph) at 2,650 m (8,694 ft) (Ar 68F-1 321 km/h)
325 km/h (202 mph) at 4,000 m (13,123 ft) (Ar 68F-1 310 km/h)
294.5 km/h (183 mph) at 6,000 m (19,685 ft) (Ar 68F-1 290 km/h)
Range: 499 km; 269 nmi
Service ceiling: 8,100 m)
(Ar 68F-1 7,400 m)
Rate of climb: 12.6 m/s 
(Ar 68F-1 11.2 m/s )
Time to altitude: 6,000 m in 10 minutes
(Ar 68F-1 1,000 m in 1.35 minutes, 5,000 m in 10.2 minutes)
Armament: 2 × 7.92 mm mg 17 machine guns with 500 r.p. guns
Bombs: Up to 610 kg SC 10 fragmentation bombs