venerdì 25 dicembre 2020

La HMS Sheffield (D80) è stata il primo cacciatorpediniere lanciamissili della classe Type 42


La HMS Sheffield (D80) è stata il primo cacciatorpediniere lanciamissili della classe Type 42. 


La costruzione venne iniziata dalla Vickers Shipbuilding and Engineering nei cantieri di Barrow-in-Furness e venne completata dalla Swan Hunter nella regione di Tyne and Wear. La HMS Sheffield venne varata il 15 gennaio 1970 ed entrò in servizio nel 1975, iniziando a sperimentare gli allora nuovissimi sistemi di bordo nelle varie condizioni meteo di impiego operativo. Durante la sua vita operativa prese parte alla Guerra delle Falkland dove venne affondata il 4 maggio 1982 da un missile Exocet lanciato da un aereo Dassault Super Étendard dell'Aviación Naval argentina.


Costruzione

La Classe Type 42 (conosciuta appunto anche come classe Sheffield dal nome dell'unità capoclasse), è stata costruita in tre lotti; il costo di queste navi fu di oltre 30 milioni di sterline, il doppio di quello che era stato preventivato inizialmente. La chiglia venne impostata il 6 novembre 1972 nei cantieri navali Vickers a Cumbria.
I cacciatorpediniere della classe Type 42 furono progettati come navi antiaeree e il loro armamento principale era rappresentato dal Sea Dart, un sistema missilistico mare-aria in grado di colpire bersagli distanti fino a 30 miglia nautiche, pari a 56 km. La nave era armata anche con un cannone navale Mark 8 da 114mm in grado di sparare proiettili da 21 kg a una distanza di 22 km.


Storia

I primi anni di servizio

La nave venne affidata per il completamento e le prove in mare al capitano di vascello Sandy Woodward, che vista la mole di problemi presentata dalla nave declinò l'invito a partecipare alla Rivista Navale per il Giubileo di Elisabetta II nel 1975 a Portsmouth. I problemi vennero risolti solo il giorno prima della rivista, ma comunque molti difetti vennero alla luce durante le esperienze operative in servizio di squadra nell’Atlantico.


La guerra delle Falkland

Il 2 aprile 1982, il territorio britannico d'oltremare delle Isole Falkland, venne invaso dalla vicina Argentina. Il Regno Unito, distante 13.000 km, raggruppò e inviò un corpo di spedizione aeronavale che comprendeva portaerei, sottomarini e circa 7.000 soldati per riconquistare l'arcipelago. Il conflitto terminò a giugno con la sconfitta delle forze argentine.
I molteplici impegni della Royal Navy prevedevano anche il dispiegamento di una forza navale nel Golfo Persico sotto la missione Armilla Patrol. Anche la HMS Sheffield aveva preso parte in questa missione, e durante una esercitazione della First Destroyer Flottilla, comandata dall'ammiraglio Woodward, a Gibilterra ricevette l'ordine di unirsi al gruppo navale diretto verso le Falklands.
Il ruolo primario della Sheffield, insieme alle altre unità Type 42, fu quello di picchetto radar in modo da proteggere le navi britanniche dagli attacchi argentini, rimanendo però in posizione molto esposta agli attacchi aerei.


Destino finale

Il 4 maggio 1982, due giorni dopo l'affondamento dell'incrociatore Belgrano, l'aviazione di marina argentina affondò a sua volta il cacciatorpediniere HMS Sheffield. Due Super Étendard al comando del capitano di fregata Augusto Bedacarratz e del tenente di vascello Armando Mayora e armati ognuno di un missile Exocet AM39 (dei soli cinque in possesso degli argentini), decollati dalla base di Rio Grande, dopo un rilevamento da parte di un Lockheed P2V Neptune argentino, attaccarono lo Sheffield che era posto come picchetto radar in posizione avanzata insieme con la gemella Glasgow e l'altra Type 42 presente, l'HMS Coventry. La Glasgow intercettò dapprima i radar di scoperta degli Etendard a 40-50 miglia di distanza e dopo alcuni minuti i missili lanciati dagli aerei dopo una manovra di pop-up (innalzamento improvviso di quota dopo un volo radente), notificando l'allarme all'Invincible, che era la nave dove risiedeva la centrale operativa per la lotta antiaerea (AAWC - AntiAir Warfare Commander), ma questo venne considerato un falso allarme dovuto ad eco. Provvide anche ad inviare via data-link le immagini radar rilevate alla Sheffield ma per qualche motivo non vennero ricevute.
Dei due missili, uno attaccò e mancò l'HMS Yarmouth (fregata Type 12) che aveva lanciato dei chaff, ma l'altro colpì lo Sheffield che bruciò per sei giorni dopo essere stato abbandonato dall'equipaggio, che contò 20 morti e 24 feriti. La mancata rilevazione degli aerei attaccanti venne attribuita in parte al fatto che la Sheffield stesse usando in quel momento l'apparecchiatura di comunicazione satellitare (SCOT), che interferiva con le proprie ESM.


ENGLISH

HMS Sheffield was a Type 42 guided missile destroyer and the second Royal Navy ship to be named after the city of Sheffield in Yorkshire. Commissioned on 16 February 1975 the Sheffield was part of the Task Force 317 sent to the Falkland Islands during the Falklands War. She was struck by an Exocet air-launched anti-ship missile from an Argentinian Super Étendard aircraft on 4 May 1982 and foundered while under tow on 10 May 1982.

Design

The first of the Type 42 class, Sheffield, was initially fitted with the odd-looking "Mickey Mouse" ears on her funnel tops which were in fact exhaust deflectors - "Loxton bends" - for the Rolls Royce Olympus TM1A gas turbines, to guide the high-temperature exhaust efflux sidewards and minimise damage to overhead aerials. As this provided a prominent target for then-new infrared homing missiles, only Sheffield and the next two in the class the Argentinian Hércules and Santísima Trinidad had these 'ears'. Sheffield was the only one of her class to be not fitted with STWS II triple anti-submarine torpedo tubes.

Construction

Ordered in 1968 Sheffield was laid down on 15 January 1970 and built by Vickers Shipbuilding and Engineering at Barrow-in-Furness. An explosion during construction killed two dockyard workers and damaged a section of hull which was replaced with a section from an identical ship, Hércules, being built for the Argentine Navy. Sheffield was launched on 10 June 1971 by Queen Elizabeth II and was estimated to have cost £23,200,000 to build.
As the first of her class of Royal Navy destroyers, Sheffield spent her first years trialling the new systems and the Sea Dart missile system, particularly as the intended Sea Dart trials ship, HMS Bristol, suffered serious fires and problems with its steam systems restricting its use in the late 1970s. It was not until 1980 that Sheffield became effective, with Sea Dart and partial installation of electronic warfare Abbey Hill systems. Following a refit in the early 1980s, significant design issues with the ship's Type 909 radar (which was responsible for control and targeting of the Sea Dart missiles) were identified. The ship lacked an electronic countermeasures (ECM) jammer.

Service history

In June 1981 she participated in Exercise Roebuck, following which she fired five Sea Dart missiles. Following participation in Exercise Ocean Safari she sailed in November 1981 to undertake patrols in the Indian Ocean and Persian Gulf.
She was undergoing maintenance at Mombasa when Captain James Salt took over command on 26 January 1982. Both Salt (whose most recent service had been in submarines) and his second in command (who had been an anti-submarine helicopter observer) had little or no relevant experience in surface ships and little experience in air defence.
In March 1982 the ship transited north through the Suez Canal to participate in Exercise Spring Train, which was held in the Atlantic Ocean.

Departs for the Falklands

In response to the Argentine invasion of the Falklands Islands, Sheffield was ordered on 2 April 1982 to join the task force being assembled to retake the islands. Ammunition and supplies were loaded, loose fittings stowed, and unnecessary memorabilia disembarked. All carpets were removed except for those on Deck 1 and above (which subsequently caught fire when she was hit). To avoid her being mistaken for the Argentine Hércules and Santísima Trinidad, a vertical black marking was painted on the funnel and down to the side to her waterline to aid recognition.
Departing for the South Atlantic on 10 April, Sheffield reached Ascension Island on 14 April, accompanied by HMS Arrow, HMS Brilliant, HMS Coventry, HMS Glasgow to be later joined by RFA Appleleaf. They joined other vessels of the Task Force 317 and commenced operations in the Total Exclusion Zone around the Falklands on 1 May 1982.
It was British policy that any Royal Navy vessel that suspected itself to be under missile attack turn toward the threat, accelerate to maximum speed and fire chaff to prevent the ship being caught defenceless. The codeword used to start this procedure was 'handbrake', which had to be broadcast once the signal of the Super E Agave radar of Super Étendard aircraft was picked up. Within the task force, the threat from the Type 209 submarine was seen as a higher priority than the threat from the air. Following the sinking of General Belgrano, Captain Salt had ordered the ship to change course every 90 seconds to counter any potential Argentine submarine threat.

Sinking

Argentinean attack

Sheffield was first detected by an Argentine Naval Aviation Lockheed SP-2H Neptune (2-P-112) patrol aircraft at 07:50 on 4 May 1982. The Neptune kept the British ships under surveillance, verifying Sheffield's position again at 08:14 and 08:43. Two Argentine Navy Super Étendards, both armed with AM39 Exocets, took off from Río Grande naval air base at 09:45 and met with an Argentine Air Force KC-130H Hercules tanker to refuel at 10:00. The two aircraft were 3-A-202, piloted by mission commander Capitán de Fragata (Commander) Augusto Bedacarratz, and 3-A-203, piloted by Teniente (Lieutenant) Armando Mayora.
In the two weeks leading up to the attack, Argentinian pilots had been practising tactics against their own ships, including Type 42 destroyers of the same class as Sheffield, and therefore knew the radar horizon, detection distances, and reaction times of the ship radar, as well as the optimal procedure to programme the Exocet missile for a successful attack profile.[14] The technique they used is known colloquially as “Pecking the Lobes”, in reference to the aircraft probing the side lobes of the emitting radar using the Radar warning receiver. The aircraft can avoid detection by avoiding the Main lobe of the emitting radar.
At 10:35, the Neptune climbed to 1,170 metres (3,840 ft) and detected one large and two medium-sized contacts. A few minutes later, the Neptune updated the Super Étendards with the positions. Flying at very low altitude, at approximately 10:50 both Super Étendards climbed to 160 metres (520 ft) to verify these contacts, but failed to locate them and returned to low altitude. They later climbed again and after a few seconds of scanning, the targets appeared on their radar screens.
Both pilots loaded the coordinates into their weapons systems, returned to low level, and after last minute checks, each launched an AM39 Exocet missile at 11:04 while 20 to 30 miles (32 to 48 km) away from their targets. The Super Étendards did not need to refuel again from the KC-130, which had been waiting, and landed at Río Grande at 12:04.
Supporting the mission were an Argentine Air Force Learjet 35 as a decoy and two IAI Daggers as the KC-130 escorts.

On Sheffield

At approximately 10:00 on 4 May, Sheffield was at defence watches (second degree readiness), the southernmost of three Type 42 destroyers (the others being HMS Glasgow and Coventry) operating as a forward anti-aircraft picket 18 to 30 miles (29 to 48 km) to the west of the main task force which were south-east of the Falklands. The weather was fair and the sea calm with a 2-metre swell. HMS Invincible which was with the main task force was responsible for Anti-Air Warfare Coordination (AAWC). Sheffield had relieved her sister ship Coventry as the latter was having technical trouble with her Type 965 radar.
Prior to the attack, Sheffield's radar operators had been experiencing difficulty distinguishing Mirage and Super Étendard aircraft, and the destroyer may have lacked effective IFF or radar jamming. Despite intelligence briefings that identified an Exocet attack by Super Étendards as possible, Sheffield had assessed the Exocet threat as overrated for the previous two days, and disregarded another as a false alarm.
As the Type 965 could not detect low-flying aircraft, the two incoming enemy aircraft were not detected flying at 98 feet (30 m). The two planes were detected at a distance of only 40 nautical miles (74 km) by the UAA1, a radar warning receiver. This was then confirmed by the 965M long range aircraft warning radar of Glasgow when the aircraft popped up 120 feet (37 m) above sea-level for a radar check at 45 nautical miles (83 km). The Glasgow immediately went to action stations, and communicated the warning codeword 'Handbrake' by UHF and HF to all task force ships. The radar contacts were also seen by Invincible, which directed Sea Harriers on combat patrol to investigate, but they detected nothing. The AAWC on Invincible declared the radar contacts as false and left the Air Warning at yellow, instead of raising it to red.
In response to Glasgow's warning, an order to stand to was issued to the crews of the 4.5 inch gun, Sea Dart and 20 mm guns. The aircraft were detected on the forward Type 909 radar but not on the aft set. Sheffield's UAA1 sensor was then blocked by an unauthorised transmission by the ship's satellite communications systems (SCOT). No information was received via data link from Glasgow. Seven seconds later, the first Exocet missile was fired, in response to which Glasgow fired its chaff. Onboard Sheffield, it was not until smoke from the missile was sighted by lookouts that the crew realised they were under attack. The bridge officers did not call the captain to the bridge, made no call to action stations, made no evasive measures, and made no effort to prepare the 4.5-inch gun, the Sea Dart missiles, or order chaff to be fired. The antiair warfare officer was called to the operations room by the principal warfare officer, arriving just before the first missile hit.
Two Exocets had been launched, the second missile being sighted by Yarmouth and missing Sheffield, splashing into the sea a 0.5 miles (0.43 nmi) off her port beam. The Exocet that struck Sheffield impacted on the starboard side at deck level 2, travelling through the junior ratings’ scullery and breaching the Forward Auxiliary Machinery Room/Forward Engine Room bulkhead 2.4 metres (7.9 ft) above the waterline, creating a hole in the hull roughly 1.2 metres (3.9 ft) by 3 metres (9.8 ft). Contemporary accounts suggested incorrectly that the missile failed to explode, despite disabling the ship's electrical distribution systems and breaching the pressurised sea water fire main. The damage to the fire system severely hampered any firefighting response and eventually doomed the ship to be consumed by the fire.
At the time of the hit, the captain was off duty in his cabin after having previously visited the operations room, while Sheffield's anti-air warfare officer (AAWO) was in the wardroom chatting to the stewards and his assistant was in the heads. Sheffield and Coventry were chatting over UHF and communications ceased until an unidentified message was heard flatly stating, "Sheffield is hit.”

Response

The flagship, HMS Hermes, dispatched the escorts Arrow and Yarmouth to investigate, and a helicopter was launched. Confusion reigned until Sheffield's Lynx helicopter unexpectedly landed aboard Hermes carrying the air operations officer and operations officer, confirming the strike.
With the main fire fighting systems out of action due to the loss of the fire main the crew were reduced to fighting the fire using portable electrically powered pumps and buckets. The control of firefighting lacked cohesion and was uncoordinated with no emergency HQ being established, while crew members were unclear as to where Command was located. Arrow and Yarmouth assisted in fighting the fire from the outside (to little effect) by stationing themselves to port and starboard respectively.
The crew of Sheffield fought for almost four hours to save the ship before Captain Salt made the decision to abandon ship due to the risk of fires igniting the Sea Dart magazine, the loss of the combat capability of the destroyer , and the exposed position to air attack of Arrow and Yarmouth. Most of the Sheffield's crew climbed over onto Arrow, a few transferred by Gemini RHIB to Yarmouth, while some were taken by helicopter to Hermes. As Sheffield's crew departed in Arrow, Sub-lieutenant Carrington-Wood led the crew in singing "Always Look on the Bright Side of Life" from Monty Python's Life of Brian.
Over the next six days from 4 May 1982, as the ship drifted, five inspections were made to see if any equipment was worth salvaging. Orders were issued to shore up the hole in Sheffield's starboard side and tow the ship to South Georgia. Before these orders were issued, the burnt-out hulk had already been taken under tow by Yarmouth. The high seas that the ship was towed through caused slow flooding through the hole in the ship's side, causing a list to starboard and which eventually caused Sheffield to roll over and sink on the edge of the Total Exclusion Zone in 1,000 fathoms (6,000 ft; 1,800 m) of water at 53°04′S 56°56′W on 10 May 1982, the first Royal Navy vessel sunk in action since World War II.

Loss of life

Of the 281 crew members, 20 (mainly on duty in the galley area and computer room) died in the attack with another 26 injured, mostly from burns, smoke inhalation or shock. Only one body was recovered. The survivors were taken to Ascension Island on the tanker British Esk. The wreck is presently a war grave and designated as a protected place under the Protection of Military Remains Act 1986.

Board of inquiry

In response to the loss of the ship a Ministry of Defence (MOD) Board of Inquiry was convened in HMS Nelson on 7 June 1982. They reported their findings on the 28 June 1982. The board's report severely criticized the ship's fire-fighting equipment, training and procedures identifying that the critical factors leading to loss of Sheffield were:
  • Failure to respond to HMS Glasgow's detection and communication of two approaching Super Etendards by immediately going to action stations, activating the Sea Dart and launching chaff decoys;
  • Lack of ECM jamming capability;
  • Lack of a point defence system;
  • Inadequate operator training, in particular simulated realistic low-level target acquisition.
Slow response of the available Type 909 Sea Dart tracking radar and its operator limited the possible response.
The spread of the fire was not adequately controlled due to the presence of ignitable material coverings, lack of adequate curtains and sealing to restrict smoke and fires. As well there was a shortage of breathing apparatus while the forward escape manholes were found to be too small for men wearing breathing apparatus.
Captain Salt's handling of the ship following the impact of the missile and his later decision to abandon the ship were not faulted. The board however found that the principal warfare officer and the anti-air warfare officer (AAWO) were guilty of negligence. Admiral John Fieldhouse, the commander in chief of the navy decided not to court martial them, undertake any other disciplinary action or any form of formal administrative proceedings.
It was not until 2006 following an extensive campaign by ex-RN personnel, that a heavily censored summary of the board’s findings that concealed all of the board’s key conclusions and criticisms, including the findings of negligence was released by the Ministry of Defence under UK Freedom of Information laws.
In 2015, a MOD re-assessment of the attack concluded that the Exocet warhead did indeed detonate inside Sheffield, with the results supported by analysis using modern damage analysis tools not available in 1982 and evidence from weapon hits and trials conducted since the end of the Falklands campaign.
In 2017, a complete copy of the report was issued, revealing information that according to the Guardian had been "suppressed" from the summary of the board’s findings in the 2006 release. The Guardian explained the missing information by the British Government's attempts to sell Type 42 destroyers at the same time. In the "uncensored" report, multiple issues that left the ship unprepared for the attack were identified, including findings of negligence by two officers who according to the Guardian "escaped courts martial and did not face disciplinary action, apparently in order to avoid undermining the euphoria that gripped much of the UK at the end of the war". Among other findings, the "uncensored" report showed that the ship was not sufficiently prepared to ward off an attack, during the attack the anti-air warfare officer was not in the operations room, while his assistant had gone to the restroom. The anti-air warfare officer did not expect Sheffield to be in the range of attack.

Fire

The sinking of Sheffield is sometimes blamed on a superstructure made wholly or partially from aluminium, the melting point and ignition temperature of which are significantly lower than those of steel. However, this is incorrect as Sheffield's superstructure was made entirely of steel. The confusion is related to the US and British navies abandoning aluminium after several fires in the 1970s involving USS Belknap and HMS Amazon and other ships that had aluminium superstructures. The sinking of the Type 21 frigates Antelope and Ardent, both of which had aluminium superstructures, probably also had an effect on this belief, though these cases are again incorrect and the presence of aluminium had nothing to do with their loss.
The fires in Sheffield and other ships damaged by fire caused a later shift by the Royal Navy from the nylon and synthetic fabrics then worn by British sailors. The synthetics had a tendency to melt on to the skin, causing more severe burns than if the crew had been wearing non-synthetic clothing.

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giovedì 24 dicembre 2020

L'Antonov An-71 (in cirillico Антонова Ан-71, nome in codice NATO Madcap)


L'Antonov An-71 (in cirillico Антонова Ан-71, nome in codice NATO Madcap) era un aereo AWACS ad ala alta progettato dall'OKB 153 diretto da Oleg Konstantinovič Antonov, sviluppato in Unione Sovietica nei primi anni ottanta del XX secolo e rimasto allo stadio di prototipo.


Storia del progetto

Al termine degli anni settanta il blocco occidentale disponeva di alcuni modelli di aereo con compiti di scoperta radar e sorveglianza aerea, la United States Air Force e le principali forze aeree delle nazioni aderenti alla NATO i Boeing E-3A e la United States Navy il Grumman E-2A, quest'ultimo utilizzato con profitto anche dall'israeliana Heyl Ha'Avir nel 1982, durante l’invasione del Libano.
Nello stesso periodo l’aviazione sovietica era equipaggiata con il quadrimotore Tupolev Tu-126 il quale, tuttavia, non era in grado di svolgere il compito nel controllo diretto delle operazioni militari come i suoi analoghi di produzione statunitense. Per ovviare alla carenza nel 1982 il governo sovietico, più precisamente su iniziativa dei ministeri della Difesa, dell'aviazione e dell'industria radioelettronica, decise di avviare un programma di ricerca su un sistema aereo operativo-tattico DRLO incaricandone lo sviluppo all'OKB-153 Antonov di Kiev, nell'allora Repubblica Socialista Sovietica Ucraina, ed alla moscovita NPO Vega. Le specifiche tecniche vennero emesse tra il 1982 e il 1983 dalla Voenno-vozdušnye sily SSSR (V-VS), l'aeronautica militare sovietica, coadiuvata dal suo comando di Difesa aerea nazionale, Protivo-Vozdushnoj Oborony o P-VO, e prevedeva che il nuovo velivolo avesse un’autonomia oraria di cinque ore, ed il radar installato avesse la possibilità di inseguire contemporaneamente fino a 120 bersagli. Come piattaforma l’ufficio tecnico dell’OKB 153 valutò dapprima a possibilità l’An-12, poi l’An-32 optando, infine, per una apposita versione dell’aereo da trasporto a reazione An-72, dotato di capacità STOL.
Il nuovo modello fu designato An-71, ed era caratterizzato dal vistoso rotodome dorsale posizionato sopra l'elemento verticale dell'impennaggio, dall’adozione dei propulsori turboventole Progress D-436K, integrati da un turbogetto Rybinsk RD-38A posizionato in coda. Il Consiglio dei Ministri approvò lo sviluppo del velivolo il 9 gennaio 1984, confermando l’ingegnere A.I Naoomenko a capo del team di progettisti, ed ordinando la produzione di due prototipi e una cellula per prove statiche, da realizzarsi presso lo stabilimento di Kiev-Svyatoshino.


Descrizione tecnica

L’Antonov An-71K era un velivolo monoplano, trimotore, di costruzione interamente metallica. L'ala, di forma trapezoidale, era montata in posizione alta, mentre la fusoliera, del diametro di 3,1 m, era semimonoscocca. Il carrello triciclo anteriore era completamente retrattile, con le gambe principali che alloggiavano, in posizione centrale, all'interno della parte inferiore della fusoliera.
L'equipaggio era composta da sei persone, due piloti, un ingegnere di volo e tre operatori di missione, ed alloggiava in un abitacolo pressurizzato. Il velivolo era dotato di sistema automatico di soppressione del fuoco (Fire Suppression System), e sistema di sghiacciamento delle ali.
I propulsori principali erano due turboventole Progress D-436K, eroganti la potenza di 7 500 kgf, integrati da un turbogetto Rybinsk RD-38A posizionato in coda, erogante 2 900 kgf, e con lo scarico sotto l’impennaggio al fine di favorire la corsa di decollo. Il carburante, contenuto in sette serbatoi, era pari a 16.250 litri.
La dotazione elettronica comprendeva un radar di navigazione ognitempo Gradiyent, un sistema IFF SRO-1P Parol’-2D, un sistema di navigazione inerziale I-21, un sistema di registrazione dei dati di volo MSRP-64M-2.
Il radar di scoperta doppler a impulsi era un NPO "Vega-M", la cui antenna era contenuta in un rotodome, posizionato nella parte superiore dell’impennaggio di coda, e rotante sui 360°. Il radar "Vega-M" aveva una portata massima di scoperta di 350-370 km, e 200-350 km in tracking, e poteva scoprire fino a 400 bersagli, inseguendone contemporaneamente fino a 120.


Impiego operativo

Il primo di essi (numero di serie 01 o URSS-780.151) volò per la prima volta il 12 luglio 1985 nella mani dei collaudatori A.V. Tkachenko e S.A.Gorbik, e fu presentato ufficialmente al Segretario generale del PCUS Michail Gorbačëv a Kiev il 25 giugno successivo. Il secondo prototipo andò in volo per la prima volta il 19 febbraio 1986 nelle mani dei collaudatori G. Lysenko e A.V. Tkachenko e fu poi presentato alle autorità sovietiche sulla base aerea di Kubinka nell’estate del 1988. I due prototipi volarono per un totale di 1.030 ore in 649 missioni, e poi il programma fu definitivamente abbandonato. Dopo lo dissoluzione dell'Unione Sovietica la società Antonov cercò di commercializzare l’An-71, e negli anni duemila propose, senza successo, la vendita al governo indiano di alcuni esemplari al prezzo di 200 milioni di dollari americani. Nel 2010 uno dei prototipi è stato trasferito all'Ukraine State Aviation Museum per il restauro e la successiva esposizione al pubblico.


La prevista versione imbarcata

Verso la fine del 1982 la Voenno-morskoj flot, la marina militare sovietica, valutò l’adozione di una particolare versione imbarcata dell’An-71, da impiegare sulla nuova superportaerei Ul'janovsk, designata An-75. Tale versione era appositamente progettata per l’impiego su portaerei, e l'AV-MF richiese l’installazione del radar di scoperta aerea "Kvant-M" in sostituzione del "Vega-M", il posizionamento dei propulsori in gondole subalari anziché sopra l’ala, rendendo l’aereo simile al successivo An-74TK-300, e l’adozione di ulteriori modifiche strutturali e aerodinamiche. Considerato troppo costoso per l’adozione, gli venne preferito il modello Yak-44E, ma il crollo dell’unione Sovietica e la successiva crisi economica posero fine ad ogni tentativo di acquisto.


Versioni

  • An-71 (numero di serie 01 o URSS-780.151): fu il primo prototipo a volare il 12 luglio 1985. Attualmente si trova presso l'aeroporto Antonov;
  • An-71 (numero di serie 02): aereo usato per le sole prove statiche;
  • An-71 (numero di serie 03 o URSS-780.361): secondo prototipo volò per la prima volta il 28 febbraio 1986. Il 16 ottobre 2010 è stato trasferito presso il National Aviation Museum.

Utilizzatori
  • Unione Sovietica - Aviacija voenno-morskogo flota - utilizzato solo per valutazione comparativa.

ENGLISH

The Antonov An-71 (NATO reporting name: Madcap) was a Soviet AWACS aircraft intended for use with VVS-FA (Fighter Bomber) forces of the Soviet Air Force, developed from the An-72 transport. Only three prototypes were built before the program was cancelled.

Soviet Air Force AWACS doctrine

Prior to the fall of the Soviet Union, the Air Force was divided into three aircraft based groups of units. They were the VVS-DA (Voenno-Vozdushnye Sily Dal'naya Aviatsiya) or Long Range Aviation (Bombers), the VVS-FA (Voenno-Vozdushnye Sily Frontovaya Aviatsiya) or Frontal Aviation (Fighters, Fighter Bombers and Attack aircraft), and the VVS-VTA (Voenno-Vozdushnye Sily Voenno-Transportnaya Aviatsiya) or Military Transport Aviation. The PVO (Voyska protivovozdushnoy oborony or Voyska PVO) which was the primary fighter / interceptor and surface-based defensive force was not part of the VVS; as a result, the A-50 Mainstay AWACS aircraft and its predecessor the Tu-126 Moss served exclusively with the Voyska PVO and did not assist in the direction of tactical aircraft. The An-71 was designed to be used overland to support the VVS-FA in tactical operations. This doctrine of each force having its own AWACS planes is contrary to most Western air forces' use of land based AWACS aircraft; this doctrinal difference lead in part to the fallacy that the An-71 was designed to be used by the Soviet Navy on its aircraft carriers.

Development

Its design was based on An-72, with a completely redesigned rear fuselage supporting the radar dome (rotodome) atop the broad-chord forward-swept fin. The cargo hold contained the electronic equipment and six operators stations.
Development never progressed past the prototype stage, the first of which flew on 12 July 1985. The program was cancelled with the fall of the Soviet Union when issues with the radar Vega-M Kvant could not be resolved.
In 2010, one example was transferred to the Ukraine State Aviation Museum for restoration and display.

Carrier-based variant

The An-71 Madcap is often erroneously cited as a carrier-based AWACS aircraft, which it was not, as is already described above under AWACS doctrine. However, a highly modified design, the An-75, was proposed for use on the Soviet aircraft carriers under construction, but the AV-MF (Soviet Naval Aviation) cancelled its development when it was realized that too much of a redesign would be needed to make the An-75 safe to operate off any of the proposed aircraft carriers. The AV-MF decided to seek a second purpose-built AWACS proposal using an improved Kvant-M version of the existing An-71/An-75's Kvant Radar by the Vega-M design bureau. The An-75 would have had engines mounted under the wing rather than above, similar to the later An-74TK-300, and would have had many other structural and aerodynamic changes. In the end, the An-75 would have shared only slight commonality with the An-71/An-72 aircraft families and was deemed too costly to continue, considering the clean-sheet design of the Yak-44E.

Export

In the early 2000s, Ukraine unsuccessfully negotiated with India on the sale of an An-71, priced at US$200 million. The An-71 would have had the capability to detect 400 targets at ranges of up to 370 kilometres (230 mi).

Operators
  • Soviet Union
  • Soviet Air Force

Specifications (An-71)

General characteristics
  • Crew: 6
  • Length: 23.5 m (77 ft 1 in)
  • Wingspan: 31.89 m (104 ft 8 in)
  • Height: 9.2 m (30 ft 2 in)
  • Empty weight: 19,760 kg (43,563 lb)
  • Max takeoff weight: 32,100 kg (70,768 lb)
  • Powerplant: 2 × Progress D-436K turbofan engines
  • Powerplant: 1 × Rybinsk RD-38A turbojet engine, 31.9 kN (7,200 lbf) thrust.

Performance
  • Maximum speed: 650 km/h (400 mph, 350 kn)
  • Cruise speed: 530 km/h (330 mph, 290 kn)
  • Service ceiling: 10,800 m (35,400 ft)

Avionics

  • Vega-M Kvant search radar.

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