Fiat BR.20

Le bombardier bimoteur de Fiat raconté sur Wikipedia en anglais :

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The Fiat BR.20 Cicogna ([Vous devez être inscrit et connecté pour voir ce lien]: "[Vous devez être inscrit et connecté pour voir ce lien]") was a twin-engine [Vous devez être inscrit et connecté pour voir ce lien] of the [Vous devez être inscrit et connecté pour voir ce lien] [Vous devez être inscrit et connecté pour voir ce lien] which saw service in the [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien].

Although the BR.20 was Italy's standard medium bomber in the mid-1930s and had proven effective in the [Vous devez être inscrit et connecté pour voir ce lien], it was already obsolescent by the time Italy entered the war.

Design and development


In 1934, Regia Aeronautica requested Italian aviation manufacturers to submit proposals for a new [Vous devez être inscrit et connecté pour voir ce lien]; the specifications called for speeds of 330 km/h (205 mph) at 4,500 m (15,000 ft) and 385 km/h (239 mph) at 5,000 m (16,400 ft), a 1,000 km (620 mi) range and 1,200 kg (2,600 lb) bombload.

Although [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien], [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien] offered aircraft that mainly exceeded the speed requirements
(but not range), not all exhibited satisfactory flight characteristics or reliability.

Accepted among the successful proposals, together with the [Vous devez être inscrit et connecté pour voir ce lien] and [Vous devez être inscrit et connecté pour voir ce lien], was the BR.20 Cicogna designed by Celestino Rosatelli, thus gaining the prefix BR, (for "Bombardiere Rosatelli").

The BR.20 was designed and developed quickly, with the design being finalised in 1935 and the first [Vous devez être inscrit et connecté pour voir ce lien]
(serial number M.M.274) flown at [Vous devez être inscrit et connecté pour voir ce lien] on 10 February 1936.

Production orders were quickly placed, initial deliveries being made to the Regia Aeronautica in September 1936.

Technical description


The BR.20 was a twin-engine low-wing [Vous devez être inscrit et connecté pour voir ce lien], with a twin [Vous devez être inscrit et connecté pour voir ce lien] and a nose separated into [Vous devez être inscrit et connecté pour voir ce lien] and navigator stations.

Its robust main structure was of mixed-construction; with a slab-sided [Vous devez être inscrit et connecté pour voir ce lien] of welded steel tube structure having [Vous devez être inscrit et connecté pour voir ce lien] skinning of the forward and centre fuselage, and fabric covering the rear fuselage.

The 74 m² (796 ft²) metal-skinned wings had two [Vous devez être inscrit et connecté pour voir ce lien] and 50 ribs (also made of duralumin), with fabric-covered control
surfaces.

The hydraulically actuated main [Vous devez être inscrit et connecté pour voir ce lien] elements retracted into the engine's nacelles, and carried 106 x 375 x 406 mm wheels.

The takeoff and landing distances were quite short due to the low [Vous devez être inscrit et connecté pour voir ce lien], while the thickness of the wing did not compromise the aircraft's speed.

The twin tail allowed a good field of fire from the dorsal gun turret.

The engines were two [Vous devez être inscrit et connecté pour voir ce lien] RC 41s, rated at 1,000 [Vous devez être inscrit et connecté pour voir ce lien] at 4,100 m (13,451 ft), driving three-blade Fiat-Hamilton metal variable-pitch [Vous devez être inscrit et connecté pour voir ce lien].

Six [Vous devez être inscrit et connecté pour voir ce lien] in the centre fuselage and inner wings held 3,622 [Vous devez être inscrit et connecté pour voir ce lien] ( US gal) of fuel, with two oil tanks holding 112 L (30 US gal).

This gave the fully-loaded bomber, (carrying a 3,600 kg/7,900 lb payload) an endurance of 5½ hours at 350 km/h
(220 mph), and 5,000 m (16,400 ft) altitude.

Takeoff and landing distances were 350 m (1,150 ft) and 380 m (1,250 ft) respectively.

The theoretical ceiling was 7,600 m (24,930 ft).

Dessin d'un Fiat A 80

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Crewed by four or five, the BR.20's two pilots sat side-by-side with the engineer/radio operator/gunner behind.

The radio operator's equipment included a R.A. 350-I radio-transmitter, A.R.5 receiver and P.3N [Vous devez être inscrit et connecté pour voir ce lien].

The navigator/[Vous devez être inscrit et connecté pour voir ce lien] had a station in the nose equipped with [Vous devez être inscrit et connecté pour voir ce lien] and a vertical camera.

Another two or three crewmembers occupied the nose and the mid-fuselage, as radio-operator, navigator and gunners.

The radio operator was also the ventral gunner while the last crew member was the dorsal gunner.

Armament


The aircraft was fitted ,with a [Vous devez être inscrit et connecté pour voir ce lien] model H nose [Vous devez être inscrit et connecté pour voir ce lien] carrying a single 7.7 mm (.303 in) [Vous devez être inscrit et connecté pour voir ce lien], and was initially fitted with a Breda DR dorsal turret carrying one or two 7.7 mm (.303 in) machine guns.

This turret was unusual because it was semi-retractable : the gunner's view was from a small cupola, and in case of danger, he could extend the turret.

This was later replaced by a Fiat M.I turret carrying a 12.7 mm (.5 in) Breda, then by a Caproni-Lanciani Delta turret mounting a 12.7 mm (.5 in) Scotti machine gun (although this was unreliable), and finally by a more streamlined Breda R, armed with a 12.7 mm (.5 in) Breda;
this was a much better system that did not need to be retracted because of the lower induced drag.

The aircraft was fitted with a further 7.7 mm (.303 in) machine gun in a ventral clamshell hatch that could be opened when required.

The original defensive armament weighed 220 kg (480 lb).

The BR.20's payload was carried entirely in the bomb bay in the following possible combinations: 2 × 800 kg (1,760 lb)
bombs as maximum load, 2 × 500 kg (1,100 lb),
4 × 250 kg (550 lb),
4 × 160 kg (350 lb),
12 × 100 kg (220 lb),
12 × 50 kg (110 lb),
12 × 20 kg (40 lb),
or 12 × 15 kg (30 lb) bombs.

Combinations of different types were also possible, including 1 × 800 kg (1,760 lb) and 6 × 100 kg (220 lb),
1 × 800 kg (1,760 lb) and 6 × 15 or 20 kg (30 or 40 lb), or 2 × 250 kg (550 lb) and 6 × 50 or 100 kg (110 or 220 lb)
bombs.

The BR.20 could also carry four dispensers, armed with up to 720 × 1 or 2 kg (2 or 4 lb) HE or incendiary bomblets.

All the bombs were loaded and released horizontally, improving the accuracy of the launch.

No torpedoes were used.

Dessin 3 vues du Br 20 M sur le site russe airwar.ru, apprécié ici, n'est-ce pas !

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By the time Italy had entered World War II, a new variant, the BR.20M, had been produced and put in service.

The BR.20M had a different nose with added glazed sections for the [Vous devez être inscrit et connecté pour voir ce lien] and a slightly longer fuselage.

Also, the weight was increased because part of the fabric was substituted with metal, improving the resistance to flutter while reducing speed from 430 km/h (270 mph) to 410 km/h (260 mph)

Du même site russe airwar.ru. Le Br 20 Bis

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Cicogna vs. Sparviero


Despite the BR.20 being the winner of the 1934 new bomber competition, the Savoia Marchetti SM.79 Sparviero,
a non-competitor which was developed at practically the same time, gained a reputation that overshadowed the Cicogna, partly because of its performance in air-racing.

The performance differences between the two aircraft were minimal: both were rated at about 430 km/h (270 mph), with maximum and typical payloads of 1,600 kg (3,630 lb) and 1,250 kg (2,760 lb) respectively for a range of 800–1,000 km (500-620 mi).

Both also had three to four machine guns as defence weapons, but almost totally lacked protective armour.

Des SM 79 :

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The reasons for the Sparviero's success lay in its flying characteristics.

The Sparviero was a more difficult aircraft to fly with a heavier wingload, but overall its three engines gave more power than the two of the BR.20.

The Sparviero, weighing around the same, had a reserve of power and was capable of performing acrobatic manoeuvers, even rolls.

Its engines were more reliable than those of the BR.20 and had enough power to return to base even with one shut down.

The Sparviero's superior agility enabled it to perform as a torpedo-bomber, while the Cicogna was never considered for that role.

Over 1,200 Sparvieros were built, at least twice as many as the Cicogna.

Br 20 :

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Operational history


Shortly after entering service with the Regia Aeronautica, the aircraft became central to the [Vous devez être inscrit et connecté pour voir ce lien] campaign lauding Italian engineering.

In 1937, two stripped-down BR.20s (designated BR.20A) were built for entry into the prestigious [Vous devez être inscrit et connecté pour voir ce lien]–[Vous devez être inscrit et connecté pour voir ce lien] gaining sixth and seventh place when S.M.79s scored the first place, leaving the Fiats far behind.

They had a rounded nose similar to civil aircraft, and had all military hardware, such as defensive turrets, removed.

The internal fuel capacity was increased to 7,700 L (2,034 US gal), bringing the maximum range to 6,200 km
(3,850 mi).

In 1939, a modified long-range BR.20 version (designated BR.20L) named Santo Francesco under the command of [Vous devez être inscrit et connecté pour voir ce lien] made a highly publicised nonstop flight from [Vous devez être inscrit et connecté pour voir ce lien] to [Vous devez être inscrit et connecté pour voir ce lien] at an average speed of 390 km/h
(240 mph).

It carried 5,000 l (1,321 US gal) of fuel, increasing the range from 3,000 km (1,864 mi) to 4,500 km (2,800 mi).