A particular feature of the turbojet-engined warplanes which evolved in the late 1940s and early 1950s was their steadily increasing combination of power and performance. This was seen as useful as it improved such warplanes’ overall operational capabilities, but on the other side of the coin, there was the less attractive combined feature of greater weight, increased complexity and higher development, production and operating costs, which translated into longer runway requirements, reduced serviceability and lower procurement totals. Approaching the mid-1950s, the North Atlantic Treaty Organisation (NATO) was coming to appreciate that the greater operational capabilities of the best modern warplanes were on the verge of being overtaken by their limiting factors, and decided to investigate ways to overturn this tendency.
NATO decided that there was room for a simple, and therefore light and affordable, attack fighter that could be procured in large numbers for service with many of NATO’s tactical fighter-bomber squadrons based on existing airfields. The SACEUR (Supreme Allied Commander, Europe) technical staff therefore drew up a specification for a single-seat attack fighter characterised by robust construction, ease of maintenance even under the most difficult operational conditions, limited but effective navigation and weapon-aiming systems, and capability for the installation of any of three fixed forward-firing armaments (four 0.5-in/12.7-mm machine guns, or two 20-mm cannon or two 30-mm cannon) and carriage of an underwing load of 1,000 lb (454 kg) including two bombs or 12 3-in (76-mm) unguided air-to-surface rockets, an empty weight not exceeding 5,000 lb (2268 kg), and performance including the ability to operate from grass runways yet reach a maximum speed of Mach 0.95.
Single- and twin-engined variants
British industry had been considering a move in this direction as a private venture, and its leading contender was the Folland Fo.141 Gnat, evolved from the Fo.139 Midge prototype. The edge appeared to lie with the French, however, for both the air force and industry had been working toward the same conclusion as NATO for some time. This resulted in the development of two basic types from Dassault and Breguet. The French approach to the lightweight fighter concept was somewhat more complex than that of the British, for Gallic endeavours were directed toward the development of single- and twin-engined variants of both basic designs, the single-engined variants being directed at the NATO requirement and the twin-engined variants at the French air force’s need for an attack fighter with greater operational reliability.
The half-brother Dassault types were the Dassault Mystère XXII and Mystère XXVI aimed at the French and NATO requirements with the powerplant of two Turbomeca Gabizo axial-flow turbojet engines and one Bristol Siddeley Orpheus axial-flow turbojet engine respectively: the Mystère XXII and Mystère XXVI emerged as the Etendard II and Etendard VI, the latter with a SNECMA Atar 101 axial-flow turbojet engine in the absence of the planned Orpheus. Neither type was accepted for production, but Dassault had long thought the type too small for real operational utility and therefore evolved the Etendard IV as a scaled-up version with an Atar 101E-4 engine, and this paved the way for the Etendard IVM carrierborne strike and attack fighter with the powerplant of one Atar 8 engine.
Breguet had meanwhile been moving along a parallel track with its Br.100 design, which was named Taon (horsefly, and also an anagram of NATO) and also schemed in single- and twin-engined forms as the Br.1001 and Br.1100 respectively. Design work on the Taon began in July 1955, but was temporarily halted in February 1956 when evaluation of a model in a US wind tunnel suggested that much improved performance could be achieved by the incorporation of partial area-ruling of the fuselage for reduced transonic drag: the wing-root bulges associated with this area ruling had the added advantage of increasing the standard fuel capacity.
Rapid development
Construction of the first Br.1001 began in January 1957, and this Br.1001.01 prototype recorded its maiden flight a mere seven months later on 26 July 1957 as an extremely attractive machine of light alloy construction. The Br.1001 was based on an oval-section fuselage carrying a high-set cockpit under a rear-hinged canopy, the powerplant of one Orpheus engine aspirated via lateral inlets below the cockpit and exhausting via a plain nozzle at the extreme tail, a mid-set swept wing with leading-edge slats and a trailing-edge combination of inboard flaps and outboard ailerons, a swept vertical tail surface with an inset rudder, a low-set tailplane of the all-moving type, and retractable tricycle landing gear with a single wheel on each unit.
Flight trials revealed the Br.1001.01 to have good performance and attractive handling without any major vices, and after the incorporation of the fuel-carrying wing root bulges this prototype in April 1958, set a 539.6 nm (621.4 mile; 1000 km) closed-circuit speed record of 564.2 kt (649.7 mph; 1046.65 km/h) or Mach 0.948 at 25,000 ft (7620 m). The machine raised this record to 580 kt (667.98 mph; 1075 km/h) just three months later.
The Br.1001.02 second prototype differed from the Br.1001.01 in minor aerodynamic details, and was also lengthened by 1 ft 5.25 in (0.438 m). The Br.1001 fully met the NATO requirement, and from February 1957 was evaluated against the other contenders. Ultimately, the NATO panel’s decision went to an Italian contender, the Fiat G91.
The Br.1100.01 prototype first flew in March 1957 with the powerplant of two Gabizo engines each rated at 2,469 lb st (10.98 kN) dry and 3,307 lb (14.71 kN) with afterburning, but the French air force later dropped its requirement and further development of the Br.1100 was cancelled. The same fate befell the Br.1001 after NATO’s decision had gone to the G91, and this also meant the end of derivatives such as the Br.1002 missile-armed interceptor, the Br.1003 with the wing of the Br.1100 and the powerplant of one Orpheus BOr.12 engine rated at 6,810 lb st (30.29 kN) dry and 8,170 lb st (36.34 kN) with afterburning, and the enlarged Br.1005.
Specification
Breguet Br.1001.02 Taon
Type: experimental aeroplane for use as a lightweight attack fighter prototype
Accommodation: pilot on a Martin-Baker Mk 4 ejection seat in the enclosed cockpit
Armament: four 0.5-in (12.7-mm) Colt-Browning M3 fixed forward-firing machine guns with 300 rounds per gun in the lower sides of the forward fuselage, and up to 2,000 lb (907 kg) of disposable stores carried on four hardpoints (all under the wing with each unit rated at 500 lb/227 kg), and generally comprising two or four 500-lb (227-kg) bombs, or two Nord 5110 (AS.20) ASMs, or two Matra Type 116C multiple launchers each carrying 19 2.68-in (68-mm) air-to-surface unguided rockets
Equipment: standard communication and navigation equipment, plus a gyro weapons sight
Powerplant: one Bristol Siddeley Orpheus BOr.3 axial-flow turbojet engine rated at 4,850 lb st (21.57 kN) dry
Fuel: internal 99 Imp gal (118.9 US gal; 450 litres); external fuel none; no provision for inflight refuelling
Wingspan: 22 ft 3.75 in (6.80 m); area 158.23 sq ft (14.70 m²)
Fuselage: length 38 ft 3.75 in (11.68 m) including probe and 36 ft 10.5 in (11.24 m) excluding probe; height 12 ft 1.75 in (3.70 m)
Weights: empty 7,551 lb (3425 kg); normal take-off 11,464 lb (5200 kg); maximum take-off 12,258 lb (5560 kg)
Performance: maximum level speed 644 kt (742 mph; 1194 km/h) at sea level declining to 607 kt (699 mph; 1125 km/h) at 25,000 ft (7620 m); cruising speed 391 kt (450.5 mph; 725 km/h) at optimum altitude; initial climb rate not available; service ceiling not available; maximum range 1,000 nm (1,151.5 miles; 18853 km); radius 150 nm (173 miles; 278 km) with maximum warload