IMAM Ro.57

Ro.57
	The first IMAM Ro.57 prototype, MM-407
Role	Fighter, attacker
National origin	Italy
Manufacturer	Industrie Meccaniche e Aeronautiche Meridionali (IMAM)
Designer	Giovanni Galasso
First flight	1939
Introduction	1943
Status	Retired
Primary user	Regia Aeronautica
Number built	50 + 1 prototype
Developed into	IMAM Ro.58

The IMAM Ro.57 was an Italian twin-engined, single-seat monoplane fighter of the Regia Aeronautica. Based on a 1939 design by Giovanni Galasso the aircraft did not enter production until 1943.

Two hundred aircraft were ordered, but only 50–75 were produced in two versions, one flown as an interceptor, the other in the role of a ground attack aircraft.^[2]

Design and development

The Ro.57 was preceded by another twin engine fighter design, the Ro.53, which never entered production. The Ro.57 consisted of an all-metal, semi-monocoque fuselage with a steel skeleton and Duralumin structure. The wings were also Duralumin. It was powered by two 840 hp (630 kW) Fiat A.74 radial engines giving a maximum speed of 516 km/h, which in 1939 was faster than that of the main Italian fighter, the Macchi C.200 (504 km/h).

After testing at Guidonia it was proposed by IMAM for use as a dive bomber. This transformation, which involved the addition of dive brakes, provision for 500 kg bombs and an improved forward firing armament (adding two 20 mm cannon),^[3] took time and delayed production. The resulting aircraft was designated the Ro.57bis. Performance dropped to 457 km/h maximum speed and to 350 km/h at cruise speed. The Ro.57bis was ordered into production in 1942 and entered service with the 97° Gruppo in 1943. About 50–60 aircraft were delivered.^[4]

It is said that the Ro.57 could have been the long range interceptor that Italy lacked throughout the war. It proved to be too costly for the limited weapons it carried and it never was assigned a clear role^{[citation needed]}. A better-armed version with more powerful engines was developed as the Ro.58.

Variants

Ro.57: Single-seat fighter with Fiat A.74 radial engines, and two 12.7 mm Breda-SAFAT machine guns
Ro.57bis: The dive bombing variant fitted with dive brakes, two 20 mm cannon in addition to the 12.7 mm guns and a crutch for bombs up to 1,102 lb (500 kg) under the fuselage

Operators

Kingdom of Italy

Regia Aeronautica

Specifications (Ro.57 Bis)

Data from Warplanes of the Second World War, Fighters Volume 2 ^[3]

General characteristics

Crew: 1
Length: 8.8 m (28 ft 10 in)
Wingspan: 12.5 m (41 ft 0 in)
Height: 2.9 m (9 ft 6 in)
Wing area: 23 m² (250 sq ft)
Aspect ratio: 6.79
Empty weight: 3,497 kg (7,710 lb)
Gross weight: 5,000 kg (11,023 lb)
Powerplant: 2 × Fiat A.74 R.C.38 14-cylinder air-cooled radial piston engines, 627 kW (840 hp) each

Performance

Maximum speed: 501 km/h (311 mph, 271 kn) at 5,000 m (16,000 ft)
Cruise speed: 390 km/h (240 mph, 210 kn)
Range: 1,200 km (750 mi, 650 nmi)
Service ceiling: 7,800 m (25,600 ft)
Time to altitude: 6,000 m (20,000 ft) in 9 min 30 s
Wing loading: 217 kg/m² (44 lb/sq ft)
Power/mass: 0.25 kW/kg (0.15 hp/lb)

Armament

Guns:

2 × 12.7 mm Breda-SAFAT machine guns (Ro.57)

or

2 x 12.7 mm Breda-SAFAT machine guns + 2 x 20 mm MG 151 cannon

Bombs: Up to 500 kg (1100 lbs) of bombs (Ro.57bis)

References

^ IMAM Ro.57
^ Angelucci, Enzo (2001). The Illustrated Encyclopedia of Military Aircraft 1914 to the Present. Edison, NJ: Chartwell books. pp. 232–233. ISBN 0-7858-1359-4.
^ ^a ^b Green, William (1961). Warplanes of the Second World War, Fighters Volume 2. London: Macdonald. pp. 153–154.
^ Green, W; Swanborough, G (1994). The Complete Book of Fighters. Smithmark. ISBN 0-8317-3939-8.