If the Amiot 143 were regarded, justly or unjustly, as the ugliest of the inter-war aircraft to be produced in France, the Amiot 340.01 prototype bomber which flew for the first time on 6 December 1937 had the right to claim that it was the most elegant then designed by any nation. It had originated as a long-range mail transport (a single prototype being built under the designation Amiot 341), but before this had flown it was converted to a twin-engined bomber for operation by a crew of three. The powerplant comprised two Gnome-Rhône 14N 0/1 radial engines, each rated at 920 hp (686 kW) at 12,140 ft (3700 m). ln this form redesignated Amiot 340.01, the prototype was flown for official acceptance trials at the end of March 1938.

As a result of these trials, the Service Technique de l'Aéronautique advised the Amiot company of the modifications required before a production order could be placed. These, together with development improvements introduced by the company, included the installation of 1,020 hp (761 kW) Gnome-Rhône 14N 20/21 engines; the provision of accommodation for a fourth crew member to man a new ventral gun position, firing through a floor hatch aft of the bomb bay and the introduction of a new tail unit, the tailplane having a marked degree of dihedral and twin end plate fins and rudders. In this form the aircraft was redesignated Amiot 351.01, and was handed over for flight testing towards the end of January 1939.

An Amoit 351 of Groupe de Bombardement II/34 Armée de l'Air (Bomber Group II/34 Armée de l'Air) - Orano-La Sénia (Algeria) 1940

These trials, conducted successfully, led to a number of variants, three of them being produced in prototype form with the remainder saw the light of day only on paper as projected designs. Production versions included the Amiot 351 and 354, these differing from the 351.01 prototype in having wing span reduced by 6 1/2 in (0.17 m), length increased by 1 ft 7 1/2 in (0.50 m), and a reduction in wing area of 5.38 square ft (0.50 m2). The Amiot 351 retained the twin fin/rudder tail unit of the prototype, the vertical surfaces being increased in area, but the Amiot 354 reverted to the single-fin and rudder of the Amiot 340.01 prototype. In other respects their airframes were generally similar, comprising a high-set cantilever monoplane wing with wide- span ailerons and split trailing-edge flaps. The very clean tapered circular cross-section fuselage was a monocoque structure and the main units of the tailwheel type landing gear retracted aft into the rear of the engine nacelles. Crew accommodation was provided for the bombardier/navigator in the fuselage nose, pilot almost in line with the propellers, a gunner in the dorsal turret, and radio operator/gunner in the lower fuselage aft of the bomb bay.

Engines differed between these two production aircraft, and accounted for most of the variants. Thus the Amiot 350 was a project to re-engine the Amiot 340.01 with two Hispano-Suiza 12Y 28/29 engines; the production Amiot 351 had two Gnome-Rhône 14N 38/39 engines each developing 950 hp (708 kW) at 12,140 ft (3700 m); the Amiot 352 was a project with two Hispano-Suiza 12Y 50/51 engines each rated at 1,100 hp (820 kW) at 10,695 ft (3260 m); and the Amiot 353 was yet another project, with two Rolls-Royce Merlin III engines each developing 1,030 hp (768 kW) at 16,250 ft (4950 m). The production Amiot 354 had 1,160 hp (865 kW) Gnome-Rhône 14N 48/49 engines, and was followed by two prototypes and one project. The first of these was the Amiot 355.01, with two 1,200 hp (895 kW) Gnome-Rhône 14R 2/3 radials with two-speed super-chargers. Then came the Amiot 356.01 with two 1,130 hp (843 kW) Rolls-Royce Merlin X engines and finally there was the Amiot 357, intended as a high-altitude bomber with pressurised accommodation and two Hispano-Suiza 12Z turbocharged engines.

All of this activity would suggest a vast production programme but this, unfortunately, was not the case. So far as France was concerned in relation to international problems, the reorganisation of its aviation manufacturers into a nationalised industry could not have come at a worse time. Even those companies which opted out, and Amiot was one of them, were affected by the disruption to all branches of the industry. This meant that production examples of the very promising prototype which had first flown in December 1937 were not entering service until it was too late for them to contribute any worthwhile support in the attempt to halt the relentless advance of the German divisions. The first two Amiot 354s, for example, had not been delivered to an operational unit until 7 April 1940, and of the total of about 62 which had been delivered before the fall of France in June 1940, hardly any were used operationally as they were short of armament and/or equipment, or were destroyed on the ground by German attacks.

A number were overhauled at a later date and, provided with additional fuel tanks in the bomb bay, were used by Air France for services between Vichy France and overseas territories. Four were seized by the Germans and used by the Luftwaffe. One Amiot 354 was abandoned by them as their forces retreated into Germany and this survived to serve with the Groupe de Liaisons Aeriennes Ministerielles from 1946.

Variants

Amoit 340.1 - the Amiot 340.01 prototype bomber which flew for the first time on 6 December 1937.

Amoit 351.1 - After the testing of the prototype, many changes were requested prior to production, in this form the aircraft was redesignated Amiot 351.01, and was handed over for flight testing towards the end of January 1939.

Amoit 351/354 - Production versions included the Amiot 351 and 354, these differing from the 351.01 prototype in having wing span reduced by 6 1/2 in (0.17 m), length increased by 1 ft 7 1/2 in (0.50 m), and a reduction in wing area of 5.38 square ft (0.50 m2). The Amiot 351 retained the twin fin/rudder tail unit of the prototype, the vertical surfaces being increased in area, but the Amiot 354 reverted to the single-fin and rudder of the Amiot 340.01 prototype.

Amoit 350 - The Amiot 350 was a project to re-engine the Amiot 340.01 with two Hispano-Suiza 12Y 28/29 engines.

Amoit 352 - The Amiot 352 was a project with two Hispano-Suiza 12Y 50/51 engines each rated at 1,100 hp (820 kW) at 10,695 ft
(3260 m).

Amoit 353 - The Amiot 353 was yet another project, with two Rolls-Royce Merlin III engines each developing 1,030 hp (768 kW) at 16,250 ft (4950 m).

Amoit 355.01 - A prototype, the Amiot 355.01 was equipped with two 1,200 hp (895 kW) Gnome-Rhône 14R 2/3 radial engines with two-speed super-chargers.

Amoit 356.01 - An other prototype, the Amiot 356.01 was equipped with two 1,130 hp (843 kW) Rolls-Royce Merlin X engines.

Amoit 357 - An other prototype, the Amiot 357, intended as a high-altitude bomber with pressurised accommodation and two Hispano-Suiza 12Z turbocharged engines.

Specifications (Amiot 354)

Type: Four Seat Medium Bomber

Design: Amiot Design Team

Manufacturer: SECM

Powerplant: Two 1,060 hp (790 kW) Gnome-Rhône 14N 48/49 radial piston engines.

Performance: Maximum speed 298 mph 480 km/h at 13,125 ft (4000m); cruising speed 217 mph (350 km/h); service ceiling 32,810 ft (10000 m).

Range: 1,553 miles (2500 km) on internal fuel.

Weight: Empty 10,417 lbs (4725 kg) with a maximum take-off weight of 24,912 lbs (11300 kg).

Dimensions: Span 74 ft 10 3/4 in (22.83 m); length 47 ft 6 3/4 in (14.50 m); height 13 ft 4 1/2 in (4.08 m); wing area 721.18 sq ft (67.00 sq m).

Armament: One 20 mm cannon in dorsal turret and two 7.5 mm (0.295 in) MAC machine-guns (one each in nose and ventral positions), plus up to 2,646 lbs (1200 kg) of bombs.

Variants:Amoit 340.01, Amoit 350, Amoit 351.01, Amoit 351, Amoit 352, Amoit 353, Amoit 354, Amoit 355.01, Amoit 356.01, Amoit 357.

Avionics: None.

History: First flight (340.01) 6 December 1937; First flight (351.01) January 1939; first delivery (354) 7 April 1940.