The Aermacchi or Macchi MB-326 is a light military jet aircraft designed in Italy. Originally conceived as a two-seat trainer, there have also been single and two-seat light attack versions produced. It is one of the most commercially successful aircraft of its type, being bought by more than 10 countries and produced under licence in Australia, Brazil and South Africa. It set many category records, including an altitude record of 56,807 ft (17,315 m) on 18 March 1966. More than 600 were built.[1]
In the 1950s, before the advent of the turboprop, many countries operated small jet trainers with a similar performance to their full-blown aircraft. Some nations started to develop aircraft like the Fouga Magister, the T-37, the Jet Provost, and the Aero L-29. Italy, still recovering from the war years, could not afford the development of a supersonic interceptor or bomber, and developed light fighters and trainers - a lower-cost solution.
The MB-326 was designed by Ermanno Bazzocchi at Macchi. Bazzocchi considered many configurations, the one chosen was a single-engined design. The airframe was a robust and light structure, metallic, simple and cheap; powered by an efficient engine, the Armstrong Siddeley Viper. This engine was designed as a short-life unit originally destined for target drones, but showed itself to be far more reliable. This airframe and engine combination led, in 1953, to the MB-326 project.
The contest specifications were:
• Max load 7 g at maximum weight
• 5,000 hours lifespan, 50–60 hours between servicing, stall-alert (at 15 km/h (9 mph) more than stall speed)
• Take-off at max load in 800 m (2,625 ft) over a 15 m (50 ft) high obstacle, or 500 m (1,640 ft) at light weight, landing in 450 m (1,480 ft) at minimum weight
• Speed (min-max): 110/130–700 km/h
• Rate-of-climb must be at least 15 m/s (2,950 ft/min) and endurance should be three hours at 3,000 m (9,840 ft).[2]
There were several modifications to the MB-326 project: the horizontal tail surfaces lost their negative dihedral angle, the airbrakes (two in the wings) became one, in the ventral position. In 1956 the AMI approved the project and requested two prototypes (MM.571 and 572) and one airframe for static tests. No weaponry or pressurization was needed, but Bazzocchi introduced them.
The first prototype made its maiden flight on 10 December 1957,[3] flown by chief test-pilot Guido Carestiato, and the second flew the following year.[4] The plane showed very good characteristics, but the modifications affected the weight, which was 400 kg (880 lb) more than the initial estimates. The original Viper 8 engine produced 7.8 kN (1,750 lbf) of thrust, so the Viper 9 was adopted, which had 0.7 kN (147 lbf) more of thrust.
On 15 December 1958, the AMI placed an order for 15 pre-series examples. In 1960, an order for 100 aircraft was placed, establishing Aermacchi's supremacy in jet trainers.
Direct competition came from the Fiat G.80, being more powerful and the first real Italian jet, having flown five years earlier, but it was also heavier, bigger and more expensive. It lost the contest, remaining without a market.
Design
The MB-326 was a low-wing monoplane with an all-metal (light alloy) structure. Powered by a Rolls-Royce Viper non-afterburning turbojet with low air-intakes in the wing roots. Each wing had 22 ribs and two spars. The fuel system had one large tank in the middle-fuselage and two in the wingtips. The aft fuselage was almost entirely dedicated to the engine, from just behind the wings. The cockpit had a tandem configuration, which was chosen to give a better aerodynamic fuselage (slimmer) than the more usual side-by-side arrangement. There was a long, low bubble canopy. The rear of each wing had flaps, and ailerons with a trim surface. An anti-sliding winglet was added to increase stability at the mid-wing.
The MB-326 was one of the last Italian aircraft to set any records, when Guido Carestiano set the C1D group 1 category altitude record of 15,489 m during August 1961.
In the meanwhile, the first machines, after a very long development, finally arrived at the 214° Group's Lecce-Galatina school; temporarily fielded at Brindisi. The type entered service with 43° Flyer course on 22 March 1962. These machines replaced T-6 Texans, and within 130 hours the pilots were as ready as after having 210 hours training in T-6s. This solution was much costlier, but the enthusiasm was great and, with G-91T advanced trainers, there was an "entirely-jet" training course for AMI pilots, and moreover they were all national aircraft. Differing from G.91s that were never convincing as light fighters, the MB-326s immediately scored several export successes.
Eight MB-326Bs were ordered by Tunisia in 1965. These were developed from basic MB-326s with a weapons capability, with the 37th series AMI aircraft being converted (it had civilian markings I-MAKC). The main innovation was its ground attack capability, with six underwing pylons, holding a maximum of 907 kg of stores. In the same year, Ghana ordered nine similar MB-326Fs.
The "A" and "C" models were never realized. The "A" was intended as a light attack aircraft, with two 7.62 mm machine-guns in the nose, but was never built. Later, some MB-326s were called "A", but this only meant that they were fitted with an ADF Marconi AD-370. The "C" version was to have the NASARR radar in the nose, to train F-104 pilots, but it only appeared as a mock-up.
Alitalia ordered four aircraft as trainers in the "D" version; demilitarized and equipped with special instruments to train pilots in preparation for the new jet-liners.
• 8 February 1966, climbing records: 2 min 2 sec to 3,000 m, 3 min 56 sec to 6,000 m, 6 min 39 sec to 9,000 m, and 12,000 m in 10 min 53 sec.
• 18 March 1966, 15,690 m altitude record in horizontal flight, and 17,315 m with a launched climb.
• 18 July 1966, endurance record, with 970 km
• 2 August 1966, speed record over a 3 km straight: 871 km/h
• December 1966: speed of 880.586 km/h over 15–25 km, 831.007 km/h over 100 km, 777.667 km/h over 500 km, and another endurance record at 777.557 km
These successes showed the MB-326's performance, and established it as one of the best in its category. Peracchi displayed its agility, while Ralli concentrated on performance; there were already some customers well-satisfied with this machine.[2]
A7-043 (MB-326H) at the RAAF Base Wagga in Australia.
The Royal Australian Air Force (RAAF) used the MB-326H as a jet trainer. A total of 97 were ordered: 12 were delivered by Macchi, 18 assembled from kits in Australia, and another 67 were built by the Commonwealth Aircraft Corporation and Hawker Aircraft with the designation CA-30. They were essentially similar to the MB-326G but with improved avionics. The RAAF's aerobatic team, The Roulettes, flew the MB-326H from December 1970 until 1989. Although widely liked for its excellent handling and well-suited to its task, the service career of the MB-326 was cut short because of structural fatigue problems. The Australian fleet, for example, had a life of type extension program in the 1980s and were then re-winged in the early 1990s after a fatigue-related crash. Even so the MB-326 was supplemented by new Pilatus PC-9 trainers to reduce flying hours, and the last examples had been withdrawn by 2001.
Brazil was the main customer for the MB-326, in 1970 ordering two prototypes and 166 MB-326GCs, called the AT-26 Xavante. It was produced under license by Embraer with a further six for Togo and 10 for Paraguay. Another 17 were built in Italy for Zaire (Force Arienne Zairoise) and 23 for the Zambian Air Force.
The MB-326K (originally known as the MB-336) was the last generation model, fitted with the Viper Mk 600 engine, capable of 1,814 kg thrust to give an even better performance. The first flight took place on 22 August 1970. The two prototypes were I-AMKK and I-KMAK, the MB-326G was converted to this new model.
Dubai bought three in 1974, and a further three in 1978 (MB-326KD), Tunisia eight (MB-326KT), Ghana nine (MB-326KB) and Zaire eight (MB-326KB).
The MB-326L was essentially the MB-326K with two seats. Two MB-326LD were supplied to Dubai and four MB-326LD to Tunisia.
One of the last buyers was, again, AMI, who ordered 12 MB-326E, comprising six MB-326 updated to MB-326G, and six newly produced (MM.54384/389). They had provisions for armament, but the engine was the Viper 11 Mk 200 and not the Viper 20 Mk 540.[2]
In Italian service, the MB-326 was replaced by the MB-339 between 1981 and 1984, acting after that as fast linkage aircraft, replacing the old T-33s that were slightly faster. Unusually the MB-326 did not see service with the Frecce Tricolori aerobatic team, who kept their faster G-91R PANs (they were later replaced by MB-339s).
The MB.326 failed to impress other NATO airforces, but it did have some success amongst many Third World countries, being used as a front-line machine in local wars.
The MB-326, like its competitors the Cessna T-37 and the BAC Jet Provost, was designed and ordered in the period when the "all-through" jet trainer was a fashionable concept in many air forces. The idea was to provide a single type that could be used for both elementary and advanced training right through to near combat-ready standard. In practice it was soon discovered that the simplicity and economy of scale of operating just one type for all training purposes was far outweighed by the purchase and operating costs of a large all-jet training fleet. Most operators quickly added a cheaper piston-engined type for basic training, and the MB-326 found its primary role as a lead-in trainer to prepare pilots for transition to very high performance fighter aircraft.
The aircraft was important also for two developments: from the MB.326K the MB.326L was produced, this was the direct ancestor of the Aermacchi MB.339. With license-building in Brazil, the MB.326 opened the field to further collaborations, leading to the AMX. Neither the MB.339 nor the AMX were as successful as the MB.326, but this machine was capable of further steps in technology and commerce.
South Africa
South Africa obtained a license to produce the MB-326M (similar to the 'G' model), as the Impala Mk I in 1964 with production starting in 1966.[5] It received 40 Italian-built aircraft followed by about 125 built locally by the Atlas Aircraft Corporation,[6] using them both as trainers and in an armed configuration. Seven examples of the MB-326K were also bought as light attack aircraft, with a further 15 assembled from kits,[7] while around 78 were license-produced and known as the Impala Mk II.[2] Licence production of the single seat version began in 1974.[5]
South Africa used its Impalas in combat against the Angolans, the Cubans and several militia movements. They typically flew at 550–650 km/h at a height of 15 m to avoid the risk of being shot down or even sighted by AA defenses. One was shot down by a SA-7, another returned with a unexploded missile (SA-7,8 or 9) in its exhaust.[8]
The aircraft had many advantages over high performance jets. Although slower, it could operate from primitive, short airfields and strike within minutes. The South African Air Force (SAAF) used up to 6 x 120 kg or 4 x 250 kg bombs. The main armament consisted of 68 mm SNEB rocket-launchers (four x 6 or two x 18), and two 30 mm guns (with 300 rounds).[9] These guns were the real bonus for the Impala Mk II, helping to give a superior performance compared to the two-seat versions. The latter could carry a pair of 30 mm DEFA guns in under-wing pods. However, the dual capability as trainer-attackers was better appreciated, as was the availability of six hard points and so dual-seat versions were the most produced. Six squadrons were equipped with the Impala Mk. II in the SAAF during the 1970s and 1980s. The situation over Angola and Namibia in 1987 and 1988 was such that the Impalas were withdrawn from the front line, leaving the work to Mirages and Buccaneers.[10]
Impala Mk. IIs were also used as interceptors although it was only opportunistically, not intentionally. In several encounters in 1985 with Mi-8 and Mi-24 helicopters, they shot down a total of six. This happened during a crucial phase of the ground war, when Angolan and Cuban troops were checked in an offensive against UNITA bases. This ended in disaster when the supplies were cut off by UNITA and the SAAF and front line troops ran out of ammunition. Helicopters were being used to supply the besieged troops and the SAAF cut off this link. Two Mi-24s were shot down in the first encounter while escorting Mi-17s.[11] The MiG-21s that escorted them flew too high and did not know what was happening. Two days later the Impala Mk IIs struck again, downing two Mi-24s and two Mi-17s. The attacks on the unsuspecting helicopters were carried out with only two guns per aircraft. The Impala Mk. II, built in South Africa from an Italian design with a British engine and French guns were highly effective, they also had some Electronic Counter Measures to defend themselves. The single seat Impala Mk. IIs were also sometimes armed with Matra R550 Magic air-to-air missiles for self defence.[5] The Impala Mk II operated at extreme ranges and had to fly very low, climbing only when helicopters were seen at medium altitude. After each attack they had to return to low level to avoid interception by MiGs.
The Silver Falcons, the SAAF aerobatic team, were equipped with Impala Mk Is.
The flying school for Impalas was Flying Training School at Langebaanweg while operational squadrons were 4, 5, 6, 7 and 8 Squadrons while 85 Advanced Flying School also had a small number of Impalas to supplement their Mirage trainers.[5]
Information supplied by: http://en.wikipedia.org/wiki/Aermacchi_MB-326
No comments:
Post a Comment