Monday, February 9, 2015

Arado Ar 67 and Ar 68




Ar.68F-1 Unit: FFS A/B 32 Serial: PX+NQ This aircraft was used by A/B 32 for advanced pilot training at their base at Pardubice, Czechoslovakia. Alfred Aurass was one student to fly it in August 1942. Note the massive engine exhausts.

In the closing months of 1933 Arado flew what proved to be the sole example of the Ar 67, a smaller and lighter version of the company's earlier Ar 65; powered by a 640-hp (477-kW) Rolls-Royce Kestrel VI, it had a maximum speed of 211 mph (340 km/h). Like its antecedents, the Ar 67 was of mixed construction and was, similarly, to have carried two 7.92-mm (0.31-in) machine-guns.

Development was discontinued, however, in favour of the Arado Ar 68 which was the last biplane fighter to enter front-line service with the Luftwaffe. Reaching contemporary standards of aerodynamic efficiency, the aircraft had an oval-section fuselage of steel-tube construction, with metal panels covering the rear decking and forward sections, and fixed tailwheel landing gear whose main units incorporated wheel spats. The distinctive fin, which was to be used almost without exception in subsequent single-engined Arado designs, was introduced on the Ar 68.

The prototype Ar 68a flew for the first time in 1934, powered by a BMW VId engine providing a maximum continuous output of 550 hp (410 kW), resulting in disappointing performance. The problem was partially overcome in the Ar 68b second prototype, which was powered by a supercharged 610-hp (455-kW) Junkers Jumo 210 inverted-Vee engine, which both improved forward vision from the cockpit, and provided full power at higher altitudes. Even so, drag from the chin radiator depressed potential performance figures, and a redesigned unit was fitted to the Ar 68c third prototype which, flown in the summer of 1935, was the first to be fitted with the intended armament of two 7.92-mm (0.31-in) MG 17 machine-guns. The fourth and fifth prototypes, designated Ar 68d and Ar 68e, were powered respectively by the BMW VI and Jumo 210 engines, and were regarded as pre-production aircraft. First to enter interim small-scale production was the Ar 68F, powered by a 750-hp (570-kW) BMWVI engine Arado Ar 68 of 10. (Nacht) JG 53 'Pik As' Arado Ar 68E trainer of a Luftwaffe Jagdfliegerschule pending improved supplies of the Jumo 210 engine. As soon as better allocations of the Junkers powerplant were made, production of the Ar 68E began with initial deliveries from the spring of 1937. An improved Ar 68G was planned, but this failed to enter production as the supercharged BMW engine to power it did not materialise, and the only other variant was the single Ar 68H prototype. This introduced a sliding cockpit canopy, two additional machine-guns, and an 850-hp (634-kW) BMW 132 radial engine. In this form the Ar 68H, first flown in 1937, had a maximum speedsome42 mph (68 km/h) better than that of the Ar 68E, but by then the RLM was convinced that the day of the biplane had ended and Arado was instructed to terminate its development.

Initial deliveries of the Ar 68F were made to the Luftwaffe in the late summer of 1936, commencing with I/JG134 'Horst Wessel'. By the outbreak of World War II, most surviving Ar 68s had been relegated to advanced fighter trainer status with the Jagdfliegerschulen (fighter pilot schools).

Variants

    * Ar 68V1 : Prototype, powered by a 492 kW (660 hp) BMW VI engine. First flight in 1933.
    * Ar 68a : First prototype.
    * Ar 68b : Second prototype.
    * Ar 68c : Third prototype.
    * Ar 68d : Fourth prototype.
    * Ar 68e : Fifth prototype.
    * Ar 68E : First type to enter Luftwaffe service, powered by a 455 kW (610 hp) Junkers Jumo 210.
    * Ar 68F : Powered by a 500 kW (670 hp) BMW VI.
    * Ar 68G : Most produced variant, BMW VI (500 kW+/670 hp+)
    * Ar 68H : Only a single prototype was built. It was powered by an 634 kW (850 hp) supercharged BMW 132Da nine-cylinder air-cooled radial. It was also the first Arado fighter to have an enclosed cockpit.
Specifications (Ar 68E)

General characteristics

    * Crew: 1
    * Length: 9.4 m (30.84 ft)
    * Wingspan: 11.58 m (37.99 ft)
    * Height: 3.3 m (10.83 ft)
    * Wing area: 27.3 m² (294 ft²)
    * Empty weight: 1,840 kg (4,057 lb)
    * Max takeoff weight: 2,475 kg (5,457 lb)
    * Powerplant: 1× Junkers Jumo 210Ea supercharged V 12 engine, 671 hp (500 kW)

Performance

    * Maximum speed: 335 km/h (215 mph)
    * Range: 500 km (270 mi)
    * Service ceiling: 12,800 m (41,995 ft)
    * Rate of climb: 432 m/s (1,417 ft/min)

Armament

    * 2 × 7.92 mm (.312 in) MG 17 machine guns
    * Light bombs to 2,100 lb total

Specifications (Ar 67a)

General characteristics

    * Crew: one, pilot
    * Length: 7.9 m (25 ft 11 in)
    * Wingspan: 9.68 m (31 ft 9 in)
    * Height: 3.1 m (10 ft 2 in)
    * Wing area: 25.06 m² (269.72 ft²)
    * Empty weight: 1,270 kg (2,800 lb)
    * Loaded weight: 1,660 kg (3,660 lb)
    * Powerplant: 1× Rolls-Royce Kestrel VI, 477 kW (640 hp)

Performance

    * Maximum speed: 340 km/h (211 mph)

Armament

    * 2 × 7.92 mm (.312 in) MG 17 machine guns

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