WesWorld

[SIZE=3]Strike Aircraft of the GDAI[/SIZE]
- Loire-Nieuport LN.190 Épouvantail

Loire-Nieuport LN.190 Épouvantail / TNAC Hunlika
General characteristics
Crew: 2 (pilot, gunner-spotter)
Length: 12.5 m (41 ft)
Wingspan: 18 m (59 ft 1 in)
Height: 3.75 m (12 ft 3 in)
Wing area: 39 m² (409 ft²)
Empty weight: 2,700 kg (5,952 lb)
Loaded weight: 4,000 kg (8,818.5 lb)
Powerplant: 2 × Dietrich-Lorraine DL-411 (licensed Argus As 411), 592 hp (441 kW) each

Performance:
Maximum speed: 400 km/h at 2,600 m (248 mph at 8,000 ft)
Range: 700 km (434 mi)
Service ceiling: 8,000 m (27,550 ft)
Rate of climb: 8.5 m/s (27.9 ft/min)
Wing loading: 102.5 kg/m² (21.5 lb/ft²)
Power/mass: 110.25 W/kg (0.067 hp/lb)

Armament:
- 4 × 7.5 mm machine guns (or 2 × 12.7mm MGs) mounted in the wing roots
- 2 × 23mm HS.406 cannon in nose
- 20 × 10 kg (22 lb) bombs
- 8 × 50 kg (110 lb) bombs or rockets under wings

Notes:
- 56x built for Groupe pour la Défense Aérienne Indochinoise by AIAI Saigon.



Development
Following an exchange of correspondence between Loire-Nieuport's chief engineer at AIAI (Atelier Industriel de l'Aéronautique d'Indochine) and TNAC in 1940, the French and Thai governments agreed to cooperate on the design of an aircraft for light bombing, mid-ranged reconnaissance, aerial policing, and counter-insurgency duties. Many of the initial specifications for the plane were derived from an unfilled 1937 French Army request for a light counter-insurgency aircraft for use in Africa, although the design evolved substantially. The driving requirements were a low overall cost of construction and operation, high reliability, all-weather rough-field operation in "hot-and-dry" and "hot-and-wet" climates, protection from ground-based small arms fire, high loiter time, and a modest weapons load.

Design work started in November 1940, preceding the formal announcement of the collaboration effort, announced in December at the Paris Air Show. Design work largely took place at TNAC's design shop in Bangkok and AIAI's newer facility in Saigon, although some time was lost due to the lack of a wind tunnel in the region. The fuselage and empennage design originated from an earlier (1938) Loire-Nieuport proposal, while Thai designers worked out much of the main wing, which shared a visual similarity to the similarly-sized Focke-Wulf Fw.189. By August 1941, both AIAI and TNAC began construction of the initial prototypes. The French-built IA.30 prototype flew first on September 3rd, 1941, followed by the Thai-built prototype several days later. Testing uncovered a number of shortcomings which were addressed with the second set of prototypes in December 1941. Loire-Nieuport built several prototypes of their own in metropolitan France in October 1941, and suggested a number of further changes to the landing gear, wing and empennage design based on their initial testing. Official acceptance trials with the third set of prototypes began in March 1942 in Thailand and April in French Indochina and metropolitan France and Indochina. The Armee de l'Aire quickly accepted the design and ordered it into production by August 1942. (Acceptance data for Thailand is not known at this time.)

Design
The resulting aircraft, designated the Épouvantail ("Scarecrow") in France and the Hunlika in Thailand, featured a mid-mounted wing with two IAIA-manufactured DL-411 V-12 inline (license-built Argus As-411) engines turning three-blade propellers. The two crewmen sat in tandem, with the pilot sitting in a raised position behind the bombardier-observer. Although provision was made for a third crewman to operate a defensive machine-gun from an aft hatch-style mount, this required the removal of the armour plate behind the pilot. Armament included two 23mm Hispano-Suiza HS.406 cannon mounted in the nose and two to four lighter machine guns in the wing roots. Eight 50kg bombs or eight air-to-ground unguided rockets could be carried on the under-wing weapons rack, and underbelly mounting points could carry twenty 10kg light bombs.

As the designers tried to minimize production costs and mitigate possible maintenance issues, many features of the aircraft revolved around eliminating potential points-of-failure. The initial designs featured fixed main landing gear and a non-retractable tailwheel, although this configuration resulted in particularly poor ground-handling behavior. Efforts to fix this issue finally resulted in use of retractable tricycle landing gear, which allowed for both better ground-handling characteristics and airborne performance, albeit at the loss of the desired mechanical simplicity.

Although the initial Franco-Thai design work focused on design for hot-and-wet climates by eliminating, where possible, construction materials prone to rot or rust, the aircraft also proved suitable for desert operations with minimal modification, mainly in the installation of sand filters for the engines.

Many traditional aspects of aerial performance, such as speed and rate of climb, were not strongly emphasized due to the intended mission profile. When clean, with no external stores, the aircraft could achieve just over 215 knots and a climb rate of 8.5 meters per second. Specially-designed Fowler flaps, another concession of simplicity to performance, enhanced the short-field takeoff and landing capabilities. However, in terms of loiter time, the Épouvantail excelled: with the engines throttled back to their most efficient setting at 85 knots at under two thousand meters, the plane could achieve over eight hours of endurance on its internal fuel, even with a full load of external stores. At low speeds and low altitudes, the aircraft had a very tight turning circle, and had a very stable flight, particularly below one hundred knots.