La società Leonardo SpA e la difesa navale

La società Leonardo SpA e la difesa navale

La multinazionale Leonardo ha presentato cinque sistemi navali per la Middle Eastern Virtual Conference Expo; a causa della pandemia COVID-19 ha reso disponibile un video di un'ora per i media ed i tecnici del settore.

L'azienda ha altresì allestito uno stand virtuale con cinque sistemi d'arma navali mostrati e descritti in dettaglio:

• Sistemi di difesa anti-siluro Leonardo (schiera trainata, esca jammer)

• Mini siluro Black Scorpion

• Cannoni navali Marlin 40 mm “Marlin 40”

• Cannone navale 76/62 Sovraponte, 76 mm (3 pollici)
• Cannone navale 127/64 Vulcano (5 pollici).

Sistemi di difesa anti-siluro Leonardo “Anti-Torpedo Defense System”

Il Leonardo Anti-Torpedo Defense System può funzionare in modalità completamente automatica, oppure in modalità manuale con un operatore in loop. Il sistema comprende un sottosistema di avvertimento (un sistema sonar trainato a poppa soprannominato "Black Snake” con un pannello touchscreen e un laptop per i controlli) e il sottosistema Reaction che lancia contromisure costituite da due jammer e due esche per siluro in arrivo. Le due esche fungono da “imitazione degli obiettivi della nave” mentre la nave reale intraprende un'azione evasiva coperta dal rumore acustico prodotto dai disturbatori subacquei lanciati. L'intento è che il siluro nemico attacchi uno o due esche o venga confuso dal rumore del jammer e perda l'aggancio della nave da guerra con equipaggio. Leonardo ha dotato l'intero sistema sia leggero che compatto e può adattarsi a quasi tutte le navi grandi, piccole, logistiche o navali come navi da guerra, navi logistiche, trasporto di truppe, dragamine, mezzi di supporto e navi porta-container.

Il sonar passivo trainato lungo 6 km (3,72 miglia) funziona estendendo uno scivolo cilindrico dalla poppa della nave utilizzando un pannello di controllo collegato ad un ampio touchscreen per la gestione del sistema. L'unità di elaborazione è collegata al sistema di gestione del software che controlla i dati dell'array rimorchiato dalla nave. Il sistema Towed Array è sia dispiegabile che recuperabile e può funzionare fino a 80 KTS nel mare forza 5. Alla fine dell'array trainato si trova la boa del sonar munito di antenne lunghe quattro metri che trasformano i segnali analogici ricevuti in segnali digitali per l'elaborazione a bordo.

Una volta rilevato un siluro nemico, il sottosistema di reazione entra in azione controllando un lanciatore pneumatico in cui la pressione può essere regolata per lanciare le esche anti-siluro a distanze specifiche dalla nave.

Il Mobile Jammer Target Emulator

L’esca anti-siluro MJTE ha un diametro di 5 pollici e una lunghezza di 1,3 metri ed entra in acqua ad una distanza prestabilita regolata dalla pressione del lanciatore pneumatico. L’esca MJTE può agire sia come jammer che come esca, quindi funziona come due sistemi in uno. Una volta che il jammer-esca entra in acqua, stacca l'alloggiamento e il motore di compressione inizia a generare un rumore di inceppamento. Le esche MJTE sono recuperabili e possono essere lanciate da qualsiasi lanciatore Air-to-Air Warfare (AAW) utilizzando un contenitore pirotecnico.

IL LANCIARAZZI ODLS20 

Leonardo ha promosso il suo lanciarazzi ODLS20 con otto tubi da 130 mm per Anti-Submarine Warfare (ASW) e AAW, o i suoi lanciatori trapezoidali B529 / 8 (i lanciatori B529 / 8 sono più compatti per navi più piccole). Questi due tipi di lanciatori sono fissi a babordo e a tribordo per la protezione della nave dai siluri.

IL LANCIATORE LEGGERO B538

Per navi molto piccole, Leonardo ha promosso il suo lanciatore leggero B538 composto da un solo tubo che può essere organizzato in gruppi di tre o sei tubi in un arco rivolto verso l'esterno per la massima copertura.

IL Mini-siluro Black Scorpion

Leonardo ha notato che le operazioni Anti-Submarine Warfare (ASW) stanno passando dall'oceano aperto "Blue Water" alle zone costiere o litorali e quindi ha progettato e realizzato il siluro leggero Black Scorpion per acque poco profonde. Il Black Scorpion è pubblicizzato per essere imbarcato su navi di superficie senza pilota (USV), veicoli per incursori SEAL (SDV), motovedette, mezzi di attacco rapido, elicotteri / droni, veicoli aerei senza pilota (UAV) e navi sottomarine senza pilota (UUV). Il Black Scorpion può anche essere alloggiato all'interno di un Sonobuoy Dispenser di taglia A e lasciato cadere da elicotteri ASW.

Questo mini siluro è attualmente in fase di test di qualificazione con alcuni contratti futuri in scadenza. Il presentatore di Leonardo ha sottolineato che le qualifiche sono adatte per un mini siluro leggero, e quindi i requisiti del Black Scorpion sono più indulgenti rispetto ai siluri più pesanti e più grandi come il Black Arrow.

Il mini-siluro leggero Black Scorpion ha un diametro di cinque pollici ed una lunghezza di 1.100 mm, pesa meno di 20 chilogrammi e utilizza una batteria termica. La detonazione della testata è causata dall'impatto con il bersaglio, o da un fusibile a ritardo o da una batteria di scarica dopo il lancio. Si tratta di un siluro leggero in miniatura e si comporta come tale. Pertanto, l'utente non deve aspettarsi la portata, le prestazioni e le caratteristiche di un siluro leggero, medio o pesante comparabile; il Black Scorpion, con il suo diametro di cinque pollici, ha le stesse dimensioni delle contromisure anti-sottomarino di Leonardo.

Il Black Scorpion può anche essere utilizzato come siluro anti-siluro hard-kill o come un siluro ASW; comunque, Leonardo consiglia di acquistare siluri leggeri, medi o pesanti invece per l'utilizzo di navi di grandi dimensioni e sottomarini ASW.

Inoltre, il Black Scorpion può essere usato dai Dry Combat Submersibles (DCS) e dai SEAL Delivery Vehicles (SDV); comunque, l'SDV avrebbe bisogno dell’utilizzo di un tubo lanciasiluri interno che corrisponda alle dimensioni del siluro in miniatura; il Black Scorpion è già stato installato su di una nave lunga 10 metri, quindi dovrebbe essere tecnicamente possibile inserirsi all'interno di un SDV e DCS. Fino a dodici Black Scorpions possono essere installati su di una unità da 250 tonnellate; un midget può trasportare sei siluri: tre a babordo e tre a tribordo.

Il mini-siluro Black Scorpion non è stato ancora testato sugli UAV, ma un tale concetto è sicuramente fattibile: uno studio condotto da Leonardo ha identificato l'UAV che può essere utilizzato per montare e lanciare il Black Scorpion.

IL CANNONE IMBARCATO Naval Gun System - Marlin 40

Il sistema autonomo di cannoni navali Marlin 40mm, o "Marlin 40", può essere installato in modalità sovraponte o nello scafo, per l'utilizzo contro imbarcazioni da attacco rapido, droni ed elicotteri e non richiede licenza di esportazione “ITAR (International Traffic in Arms Regulations)”.

Il Marlin 40 ha una cadenza di fuoco selettiva di uno, 100 o 300 colpi per tiro con 72 colpi pronti per il fuoco disponibili in torretta. Il caricatore è Dual-Feed e può ospitare colpi programmabili, anche con colpi da 40/70. Colpi aggiuntivi all'esterno della torretta possono essere alloggiati se un caricatore penetra nel ponte e nello scafo; tale caricatore sottocoperta consentirebbe il carico e lo scarico di proiettili extra da 40 mm.

Il Marlin 40 può avere un sistema di controllo del fuoco remoto indipendente situato sulla plancia della nave, o una direzione elettro-ottica con una torretta munita del sistema di puntamento radar montati sulla parte superiore della torretta.

Cannone navale da 76/62 Sovraponte

Il cannone navale Leonardo 76/62 ha un montaggio di penetrazione del ponte / scafo con i seguenti parametri di prestazione:

Rateo di fuoco: 120 colpi al minuto con 76 colpi pronti al fuoco.
Gittata con proiettili convenzionali: 15-20KM (da 9,3 a 12,4 miglia), VULCANO 27KM (16,7 miglia) (balistico) a 40KM (24,8 miglia) (40 KM guidati per colpi a lungo raggio per supporto anti-superficie). Il cannone da 76/62 accetta anche proiettili da tre pollici con fusibili programmabili.
Elevazione da -15 a più 85°.
La precisione è di 0,5 m di raggio quando si spara da una posizione ferma.

Un kit multi-alimentazione sotto la torretta e che penetra nello scafo consente la selezione di più colpi dal caricatore, indipendentemente dalla posizione del proiettile nel caricatore. Una gru robotica rotante per il caricamento dei proiettili si sposta attraverso i caricatori e seleziona i colpi da caricare nell’arma. Il design dei portariviste e la gru robotizzata per il caricamento dei proiettili consentono all'operatore di vedere il tipo di colpi verticali quando vengono immagazzinati e caricati nel cannone.

Leonardo ha progettato il kit STRALES che utilizza un radar di guida alloggiato davanti alla torretta sotto una copertura ribaltabile per guidare e far volare effettivamente i proiettili DART Fin Stabilised Discarding Sabot (FSDS) verso l'intercettazione di bersagli aerei, missilistici o di superficie. Utilizzando le alette canard del DART per manovrare, i proiettili DART sono guidati dal radar, sono molto più efficaci e con una grande precisione; hanno anche una gittata maggiore rispetto a un proiettile standard da 76 mm. La distanza minima ottimale di un DART è di 4-8 metri e la distanza di sicurezza è superiore a 100 metri dopo lo sparo, allo scopo di evitare danni da schegge.

Il kit 76/62 STRALES consente ai proiettili di avere una spoletta a microonde di prossimità per la detonazione di una testata di tungsteno all'interno di un rivestimento segmentato per formare schegge esplosive entro 4-8 m metri da un bersaglio aereo o di superficie. Un video del lancio di prova di Leonardo ha effettivamente mostrato tre colpi di DART FSDS che ondeggiavano e si intrecciavano per intercettare e distruggere in modo obliquo un drone-bersaglio; i proiettili non guidati convenzionali vengono invece sparati in linea retta sul bersaglio ostile.

Il radar STRALES consente di risparmiare munizioni al cannone da 76 mm utilizzando i proiettili FSDS DART a radiofrequenza radarguidati; il DART può essere utilizzato contro attacchi missilistici, di superficie o droni. La portata stimata dei vari colpi DART è di circa 6 Km, contro le minacce volanti (in particolare missili) e di 8 Km, contro minacce di superficie.

Il radar NA30S MK2 è indipendente dalla torretta e può controllare fino a tre cannoni utilizzando onde radio in banda X e Ka e sensori ottici. La banda X viene utilizzata per il rilevamento, l'acquisizione e il tracciamento a medio e lungo raggio, mentre la banda Ka è per il rilevamento ravvicinato a bassa quota e la guida del DART FSDS da 76 mm. Con il radar NA30S MK2 installato, il kit di guida radar in torretta non è più necessario.

I proiettili guidati a raggio esteso VULCANO utilizzano un GPS e un'unità di guida inerziale. Al momento dello sparo, il proiettile VULCANO segue un percorso balistico verso l'alto, quindi un percorso di planata di correzione della rotta e quindi un percorso terminale verso il bersaglio in basso. Il proiettile GPS VULCANO ha un sensore di radiofrequenza per ricevere la guida per la correzione della rotta.

Il proiettile guidato VULCANO 76 mm è in fase di test di qualificazione con completamento previsto alla fine del 2020, inizio del 2021. I contratti dovrebbero essere completati alla fine del 2023 e oltre.

Cannone imbarcato da 127/64 VULCANO

Il cannone navale medio da 127/64 di Leonardo ha una canna raffreddata ad acqua di mare ed un alloggiamento della torretta invisibile a faccia piatta angolata. Il rateo di fuoco è di 32 colpi al minuto con 56 colpi pronti al fuoco e una precisione radiante di 0,5 m quando la nave è ferma. La gittata dei proiettili da 127/64 è di 23KM (14,2 miglia) con colpi convenzionali, o 60KM (37,2 miglia) con colpi balistici VULCANO e 85KM (52,81 miglia) con colpi VULCANO a correzione di rotta guidati; alcuni speciali proiettili VULCANO a razzo potrebbero estendere la portata oltre i 100 km (62,1 miglia). L'elevazione leggera della canna da 127/64 è compresa tra –12 e 70 gradi e il suo peso a secco è di 36,3 tonnellate (33.000 kg) senza munizioni caricate. Il caricatore della torretta del 127/64 penetra da uno a due ponti nello scafo. Il 127/64 ha quattro tamburi rotanti dei caricatori nello scafo che consentono di ricaricare e sostituire i proiettili da cinque pollici in tre dei caricatori mentre un caricatore viene utilizzato per caricare e sparare. Il ciclo di vita utile previsto da Leonardo è superiore ai 25 anni.

Il 127/64 è già pienamente qualificato e testato con il VULCANO da 127mm. Anche una variante da 155 mm (6 pollici) è stata qualificata da Leonardo, a seguito di alcuni test e dimostrazioni condotti in collaborazione con la società BAE Systems.

ENGLISH

Leonardo SpA and naval defence

The multinational company Leonardo presented five naval systems for the Middle Eastern Virtual Conference Expo; due to the pandemic COVID-19 made available a one-hour video for the media and technicians.

The company also set up a virtual stand with five naval weapon systems shown and described in detail:

• Leonardo anti-silide defence systems (trailed array, jammer bait) 
• Mini torpedo Black Scorpion 
• "Marlin 40 mm" Naval Guns 
• 76/62 Overhead, 76 mm (3 inches) 
• Naval Gun 127/64 Vulcan (5 inches).

Leonardo "Anti-Torpedo Defense System" Torpedo Defence Systems

The Leonardo Anti-Torpedo Defense System can operate in fully automatic mode, or in manual mode with a looped operator. The system includes a warning subsystem (a stern trailed sonar system nicknamed "Black Snake" with a touchscreen panel and a laptop for controls) and the Reaction subsystem that launches countermeasures consisting of two jammers and two incoming torpedo baits. The two decoys act as an "imitation of the ship's objectives" while the real ship undertakes an evasive action covered by the acoustic noise produced by the underwater jammers launched. The intent is for the enemy torpedo to attack one or two decoys or be confused by the jammer's noise and lose engagement of the manned warship. Leonardo has equipped the entire system both light and compact and can adapt to almost any large, small, logistical or naval ship such as warships, logistics ships, troop transport, minesweepers, support vessels and container ships.

The 6 km (3.72 mile) passive towed sonar operates by extending a cylindrical chute from the stern of the ship using a control panel connected to a large touchscreen for system management. The processing unit is connected to the software management system which controls the data of the array towed by the ship. The Towed Array system is both deployable and recoverable and can operate up to 80 KTS in sea force 5. At the end of the towed array is the sonar buoy fitted with four metre long antennas that transform the received analogue signals into digital signals for on-board processing.

Once an enemy torpedo is detected, the reaction subsystem enters into action by controlling a pneumatic launcher in which the pressure can be adjusted to launch the anti-silide baits at specific distances from the ship.

The Mobile Jammer Target Emulator

The MJTE anti-silide bait has a diameter of 5 inches and a length of 1.3 metres and enters the water at a predetermined distance regulated by the pressure of the pneumatic launcher. The MJTE bait can act both as a jammer and bait, so it works as two systems in one. Once the jammer-bait enters the water, it detaches the housing and the compression motor starts to generate a jamming noise. MJTE baits are retrievable and can be launched from any Air-to-Air Warfare (AAW) launcher using a pyrotechnic container.

THE ODLS20 ROCKET LAUNCHER 

Leonardo promoted his ODLS20 rocket launcher with eight 130 mm tubes for Anti-Submarine Warfare (ASW) and AAW, or his B529 / 8 trapezoidal launchers (B529 / 8 launchers are more compact for smaller ships). These two types of launchers are fixed to port and starboard to protect the ship from torpedoes.

THE LIGHT LAUNCHER B538

For very small ships, Leonardo promoted his B538 light launcher consisting of a single tube that can be arranged in groups of three or six tubes in an outward-facing arch for maximum coverage.

The Black Scorpion Mini-silide

Leonardo noted that Anti-Submarine Warfare (ASW) operations are moving from the open ocean "Blue Water" to coastal or littoral areas and therefore designed and built the Black Scorpion light torpedo for shallow water. The Black Scorpion is advertised to be boarded on unmanned surface ships (USVs), SEAL raiders (SDVs), patrol boats, rapid attack vehicles, helicopters / drones, unmanned aerial vehicles (UAVs) and unmanned submarine ships (UUVs). The Black Scorpion can also be housed inside an A-size Sonobuoy Dispenser and dropped by ASW helicopters.

This mini torpedo is currently undergoing qualification testing with some future contracts expiring. Leonardo's presenter pointed out that the qualifications are suitable for a lightweight mini torpedo, and therefore the requirements of the Black Scorpion are more lenient than for heavier and larger torpedoes such as the Black Arrow.

The lightweight Black Scorpion miniature torpedo has a diameter of five inches and a length of 1,100 mm, weighs less than 20 kilograms and uses a thermal battery. The detonation of the warhead is caused by impact with the target, either by a delayed fuse or by a discharge battery after launch. It is a lightweight miniature torpedo and behaves as such. Therefore, the user should not expect the range, performance and characteristics of a comparable light, medium or heavy torpedo; the Black Scorpion, with its five-inch diameter, is the same size as Leonardo's anti-submarine countermeasures.

The Black Scorpion can also be used as a hard-kill anti-silide torpedo or as an ASW torpedo; however, Leonardo recommends the purchase of light, medium or heavy torpedoes instead for the use of large ships and ASW submarines.

Furthermore, the Black Scorpion can be used by Dry Combat Submersibles (DCS) and SEAL Delivery Vehicles (SDV); however, the SDV would need the use of an internal torpedo tube matching the size of the miniature torpedo; the Black Scorpion has already been installed on a 10 metre long ship, so it should be technically possible to fit inside an SDV and DCS. Up to twelve Black Scorpions can be installed on a 250 ton unit; one midget can carry six torpedoes: three port and three starboard.

The Black Scorpion mini torpedo has not yet been tested on UAVs, but such a concept is certainly feasible: a study conducted by Leonardo has identified the UAV that can be used to mount and launch the Black Scorpion.

THE CANNON BOATED Naval Gun System - Marlin 40

The stand-alone Marlin 40mm naval gun system, or "Marlin 40", can be installed in overdeck or hull mode, for use against rapid attack boats, drones and helicopters and does not require an "ITAR (International Traffic in Arms Regulations)" export licence.

The Marlin 40 has a selective rate of fire of one, 100 or 300 rounds per shot with 72 ready to fire shots available in the turret. The magazine is Dual-Feed and can accommodate programmable shots, even with 40/70 rounds. Additional shots outside the turret can be accommodated if a magazine penetrates the deck and the hull; this magazine below deck would allow the loading and unloading of extra 40 mm bullets.

The Marlin 40 may have an independent remote fire control system located on the ship's bridge, or an electro-optical direction with a turret equipped with a radar sighting system mounted on top of the turret.

Ship's 76/62 Overhead Cannon

The Leonardo 76/62 naval cannon has a deck/hull penetration mount with the following performance parameters:

Rate of fire: 120 rounds per minute with 76 rounds ready to fire.
Range with conventional projectiles: 15-20KM (9.3 to 12.4 miles), VULCANO 27KM (16.7 miles) (ballistic) to 40KM (24.8 miles) (40 KM guided for long-range shots for anti-surface support). The 76/62 cannon also accepts three-inch bullets with programmable fuses.
Elevation from -15 to plus 85°.
Accuracy is 0.5 m radius when fired from a stationary position.

A multi-power kit under the turret and penetrating the hull allows multiple shots to be selected from the magazine, regardless of the position of the bullet in the magazine. A rotating robotic crane for loading bullets moves through the magazines and selects the shots to be loaded into the weapon. The magazine rack design and robotic bullet loading crane allow the operator to see the type of vertical shots when stored and loaded into the cannon.

Leonardo designed the STRALES kit which uses a guidance radar housed in front of the turret under a tilting cover to effectively guide and fly DART Fin Stabilised Discarding Sabot (FSDS) projectiles to intercept air, missile or surface targets. Using the canard fins of the DART to maneuver, DART projectiles are radar guided, are much more effective and with great accuracy; they also have a greater range than a standard 76mm bullet. The minimum optimal distance of a DART is 4-8 meters and the safety distance is more than 100 meters after firing, in order to avoid damage from shrapnel.

The 76/62 STRALES kit allows bullets to have a proximity microwave fuse for detonation of a tungsten head inside a segmented coating to form explosive shrapnel within 4-8 metres of an air or surface target. A video of Leonardo's test launch actually showed three DART FSDS shots swaying and intertwining to intercept and destroy a drone-target obliquely; conventional unguided bullets are fired in a straight line at the hostile target.

The STRALES radar saves ammunition to the 76mm cannon by using FSDS DART radio frequency radar guided FSDS bullets; the DART can be used against missile, surface or drone attacks. The estimated range of the various DART shots is about 6 Km, against flying threats (in particular missiles) and 8 Km, against surface threats.

The NA30S MK2 radar is turret independent and can control up to three guns using X and Ka band radio waves and optical sensors. The X-band is used for medium and long range detection, acquisition and tracking, while the Ka-band is for low altitude close range detection and guidance of the 76mm DART FSDS. With the NA30S MK2 radar installed, the turret radar guidance kit is no longer required.

VULCANO extended range guided projectiles use a GPS and inertial guidance unit. At the moment of firing, the VULCANO projectile follows an upward ballistic path, then a course correction glide path and then a terminal path downwards to the target. The VULCANO GPS projectile has a radio frequency sensor to receive course correction guidance.

The VULCANO 76mm guided projectile is in the qualification test phase with completion expected at the end of 2020, beginning of 2021. Contracts are expected to be completed at the end of 2023 and beyond.

VULCANO 127/64 loaded cannon

Leonardo's 127/64 medium naval cannon has a seawater-cooled barrel and an invisible flat-faced angled turret housing. The rate of fire is 32 rounds per minute with 56 rounds ready to fire and a radiant accuracy of 0.5 m when the ship is stationary. Range of 127/64 projectiles is 23KM (14.2 miles) with conventional rounds, or 60KM (37.2 miles) with VULCANO ballistic rounds and 85KM (52.81 miles) with guided course correction VULCANO rounds; some special VULCANO rocket projectiles may extend range beyond 100 km (62.1 miles). The 127/64 barrel elevation is between -12 and 70 degrees and its dry weight is 36.3 tons (33,000 kg) without loaded ammunition. The 127/64 turret magazine penetrates the hull from one to two decks. The 127/64 has four rotating magazine drums in the hull that allow five-inch bullets to be reloaded and replaced in three of the magazines while one magazine is used to load and fire. The life cycle foreseen by Leonardo is more than 25 years.

The 127/64 is already fully qualified and tested with the 127mm VULCANO. A 155mm (6 inch) variant has also been qualified by Leonardo, following several tests and demonstrations conducted in collaboration with BAE Systems.

(Web, Google, Wikipedia, Navalnews, Leonardo, You Tube)

 

Il Lockheed AH-56 Cheyenne era un elicottero composito d'attacco

Il Lockheed AH-56 Cheyenne era un elicoplano d'attacco, o con altri termini una girodina o elicottero composito, monomotore con rotore a pale rigide, realizzato dall'azienda statunitense Lockheed Corporation nella seconda parte degli anni sessanta.

Storia del progetto

L'AH-56A era il progetto vincitore del programma Advanced Aerial Fire Support System indetto dall'U.S. Army del 1965 per la realizzazione di un elicottero da attacco tecnologicamente avanzato.

Il contratto venne stipulato con la Lockheed nel 1967 ma l'azienda non fu in grado di cominciare la produzione in serie che nel 1968, e successivamente il governo annullò il contratto nel 1969. Lo sviluppo venne comunque continuato nella speranza che l'esercito decidesse infine di richiedere una nuova fornitura. Una relazione congressuale del Senato risalente al 1972 che stanziava finanziamenti per lo sviluppo degli A-10 per l'USAF e degli Harrier per la U.S. Navy sancì la fine delle speranze della Lockheed e la definitiva chiusura del progetto da parte del Secretary of Army nell'agosto 1972.

Sviluppo

Nella metà degli anni sessanta la U.S. Army ritenne che se sarebbe stato necessario dotarsi di un elicottero “gunship”, costruito appositamente per quel ruolo, caratterizzato da una superiore velocità e potenza di fuoco. Si riteneva fosse necessario per contrastare la minaccia dovuta all'incremento dell'intensità di fuoco da terra da parte dei Viet Cong e le truppe NVA, i quali spesso ricorrevano ad armamenti pesanti come mitragliatrici dal grosso calibro e razzi anticarro.

Sulla base di questa realizzazione, e con il crescente coinvolgimento in Vietnam, l'U.S. Army emanò delle specifiche per un elicottero d'attacco specializzato, l'"Advanced Aerial Fire Support System" (AAFSS). Il velivolo doveva essere in grado di mantenere una velocità di crociera di 195 kt e riuscire a raggiungere i 212 kt per brevi tratti, avrebbe dovuto riuscire a rimanere in hovering ad effetto suolo (OGE) a 6 000 ft (PA) e 95 °F (35 °C) ed inoltre avere una ottima capacità di carico utile finalizzata al trasporto di armamenti.

Nell'agosto 1964, l'U.S. Army emise il bando di concorso per la realizzazione dell'AAFSS e dopo aver valutato le varie proposte decise di selezionare come finaliste la Lockheed e la Sikorsky. Alla fine, nel novembre dello stesso anno, dichiararono vincitore il progetto Lockheed in base alla maggiore economicità di realizzazione, minori tempi di consegna e minor rischio tecnico . L'esercito emise la commessa il 17 dicembre 1965, dove era specificato, oltre alla quantità dei mezzi, la richiesta per apportare una serie di modifiche incluso l'inserimento di un pod dotato di missili aria-terra . Alla fine vennero richiesti 14 esemplari oltre a quelli proposti originariamente dalla Lockheed.

Nel marzo 1966 venne inoltre siglato un contratto di collaborazione tra l'azienda costruttrice e l'esercito finalizzato allo sviluppo congiunto del Cheyenne, quindi, nel corso dell'anno, vennero definiti le opzioni per la produzione aggiungendole al contratto originale. Nel gennaio 1967 l'U.S. Army ordinò 375 esemplari per la somma complessiva di US$ 31,4 milioni con un'opzione per una successiva fornitura una volta evasa la prima.

L'AH-56 continuava lo sviluppo di un rotore a pale rigide che precedentemente equipaggiava l'elicottero sperimentale Lockheed XH-51. Le sperimentazioni pratiche iniziarono con il volo inaugurale risalente al 21 settembre 1967 continuate fino all'incidente del 12 marzo 1969 quando, a causa del malfunzionamento su uno dei prototipi, il rotore venne in contatto con la cabina di pilotaggio uccidendo chi vi era ai comandi. Nel frattempo l'ordine dei 375 esemplari approvato nel 1968 venne annullato a causa dei tagli di bilancio nel settore difesa. La Lockheed continuò a sviluppare il progetto in proprio nella speranza della disponibilità di nuovi fondi governativi ma la destinazione di questi ultimi ad altri progetti fece interrompere all'azienda ogni ulteriore sforzo nel 1972, dopo aver realizzato solo dieci esemplari, uno dei quali distrutto durante le prove effettuate nella galleria del vento.

Dopo la cancellazione

Lo sviluppo delle nuove tecnologie necessarie alla realizzazione del Cheyenne ebbero come conseguenza l'innalzamento dei costi ed il superamento dei tempi previsti per la produzione. Questo, unito alle esperienze negative della partecipazione statunitense alla guerra del Vietnam, ad un aggiornamento delle specifiche richieste dall'U.S. Army e alle pressioni esercitate dall'USAF per cercare di promuovere l'A-10, ha portato alla scomparsa del progetto Cheyenne in favore dello Hughes AH-64 Apache e la produzione di Bell AH-1 Cobra, un elicottero di successo nelle vicende belliche nel Vietnam, che sarebbe stato assegnato all'U.S. Marine Corps oltre il 2000.

Descrizione tecnica

L'AH-56A era un elicoplano monomotore con rotore a pale rigide integrato posteriormente da un rotore anticoppia posizionato sul piano orizzontale sinistro della trave di coda e da un'elica in configurazione propulsiva posta all'apice di quest'ultima. Il corpo centrale era stretto e filante integrato dalla cabina biposto in tandem completamente chiusa, con il posto di pilotaggio posizionato posteriormente e quello riservato al copilota e mitragliere in posizione anteriore, caratterizzata dall'ampia finestratura. Lateralmente era dotato di piccole ali basse che contribuivano, seppur in misura minore, a fornire portanza. Il carrello d'atterraggio, la cui funzione era essenzialmente quella di mantenere l'AH-56 in posizione orizzontale quando era a terra, era triciclo posteriore semiretrattile, dotato anteriormente di ruote di grande diametro integrate in sponson ai lati del corpo centrale e posteriormente da un ruotino di coda integrato nella deriva di coda che si allungava verso terra. L'armamento consisteva in un cannone da 30 mm posizionato in una torretta ventrale integrato da una mitragliatrice da 7,62 mm o un lanciagranate da 40 mm installati in una torretta nel muso. Poteva anche essere equipaggiato con dei 2.75 inch rockets e missili BGM-71 TOW. Era stato concepito per raggiungere i 212 kt (393 km/h) in modo da essere impiegato come scorta armata agli elicotteri da trasporto della U.S. Army.

ENGLISH

The Lockheed AH-56 Cheyenne was an attack helicopter developed by Lockheed for the United States Army. It rose from the Army's Advanced Aerial Fire Support System (AAFSS) program to field the service's first dedicated attack helicopter. Lockheed designed the Cheyenne using a four-blade rigid-rotor system and configured the aircraft as a compound helicopter with low-mounted wings and a tail-mounted thrusting propeller driven by a General Electric T64 turboshaft engine. The Cheyenne was to have a high-speed dash capability to provide armed escort for the Army's transport helicopters, such as the Bell UH-1 Iroquois.

In 1966, the Army awarded Lockheed a contract for ten AH-56 prototypes, but as a stopgap also ordered the less complex Bell AH-1G Cobra as an interim attack aircraft for combat in Vietnam War. The AH-56's maiden flight took place on 21 September 1967. In January 1968, the Army awarded Lockheed a production contract, based on flight testing progress. A fatal crash and technical problems affecting performance put Cheyenne development behind schedule, resulting in the cancellation of the production contract on 19 May 1969.[1] Development of the Cheyenne continued in the hope that the helicopter would eventually enter service.

As American involvement in Vietnam was winding down, the Army canceled the Cheyenne program on 9 August 1972. By this time, the AH-1 Cobra was widely deployed by the Army during the Vietnam War and equipped with the TOW anti-tank missile. Controversy with the United States Air Force over the Cheyenne's role in combat as well as the political climate regarding military acquisition programs had caused the Army to amend the service's attack helicopter requirements in favor of a twin-engine conventional helicopter, viewed as less technical and more survivable. The Army announced a new program for an Advanced Attack Helicopter (AAH) on 17 August 1972, which led to the development of the Hughes AH-64 Apache.

Development

Background

Prior to the development of the AH-56, all armed helicopters had been modifications to existing aircraft designed for unarmed uses. In 1962, then U.S. Secretary of Defense Robert McNamara convened the Howze Board to review Army aviation requirements. The board recommended an airmobile division supported by 90 armed helicopters. The recommendation of the Howze Board came at the same time the Army was preparing to deploy its first armed escort helicopters to Vietnam; 15 UH-1A Iroquois were modified with systems for mounting machine guns, grenade launchers, and rocket pods.

In June 1962, Bell Helicopter presented a new helicopter design to Army officials, in the hopes of soliciting funding for further development. The D-255 Iroquois Warrior was envisioned as a purpose-built attack aircraft based on the UH-1B airframe and dynamic components, with a nose-mounted ball turret, a belly-mounted gun pod, and stub wings for mounting rockets or SS.10 anti-tank missiles.

Attack helicopter requirements

In December 1962, Combat Development Command (CDC) drafted a Qualitative Material Requirement (QMR) for an interim, commercial off-the-shelf (COTS) aircraft, with a 140-knot (161 mph, 259 km/h) cruise speed and a 1,500-pound (680 kg) payload. This was seen as an attempt by Army officials, anticipating the potential of the D-255, to acquire an interim aircraft to fill the escort role until the Army could determine the requirements for a dedicated armed helicopter. However, the Secretary of the Army disapproved the interim approach and directed that the Army look for a more advanced system that would dramatically improve over current helicopter designs.

Based on the guidance from the Secretary of the Army, CDC established Qualitative Material Development Objectives (QMDO) for a rotary-wing aircraft with 195-knot (224 mph, 361 km/h) cruise speed, 220-knot (253 mph, 407 km/h) dash speed, and the capability to hover out-of-ground-effect (OGE) at 6,000 feet (1,830 m) on a 95 °F (35 °C) day. The speed requirements were derived from the speed of aircraft the helicopter would escort. The Director of Defense Research and Engineering (DDRE) conditionally approved the changes to the development objectives, pending his review of the proposed program. He also directed the Army to determine whether or not any other helicopter could offer an improvement in performance over the UH-1B in the meantime.

As a result, the Army Material Command (AMC) conducted a study to determine if the development objectives were feasible and also established a program office for the Fire-support Aerial System (FAS). AMC recommended to narrow the competition to compound helicopters, as they were considered the only helicopter configuration at the time capable of being developed to meet the objectives. In March 1964, the Secretary of the Army advised DDRE that modification of existing aircraft would not approach the required performance of the FAS program; the Army would continue using the armed UH-1B until development of the FAS could proceed.

AAFSS competition

On 26 March 1964, the Army Chief of Staff redesignated the FAS program as the Advanced Aerial Fire Support System (AAFSS). The development objectives document (QMDO) for the AAFSS was approved in April 1964, and on 1 August 1964, the Transportation Research and Engineering Command contacted 148 prospective contractors with a request for proposals (RFP). Bell submitted the D-262, a modification of the D-255, but still a conventional helicopter design. Sikorsky submitted the S-66, which featured a "Rotorprop" that would serve as a tail rotor but as speeds increased would rotate 90° to act as pusher propeller. Lockheed submitted the CL-840 design, a rigid-rotor compound helicopter with both a pushing propeller and a conventional tail rotor mounted at the end of the tail.

The Army announced Lockheed and Sikorsky as winners of Project Definition Phase contracts on 19 February 1965. Meanwhile, the Army also continued to pursue an interim aircraft for combat in Vietnam until the AAFSS could be fielded, resulting in development of the Bell AH-1 Cobra which would become the backbone of the Army's attack helicopter fleet during and after the Vietnam War.

Lockheed and Sikorsky developed proposals for their respective designs, establishing three configurations to satisfy both the development objectives and a revised RFP based on a draft requirements document. An evaluation board studied each company's proposal and then submitted its recommendation to a selection authority council on 6 October 1965. On 3 November 1965, the Army announced Lockheed as the winner of the AAFSS program. The Army perceived Lockheed's design as less expensive, able to be delivered sooner, and a lower technical risk than Sikorsky's Rotorprop. On 17 December 1965, the Army released the final requirements document. The document added fourteen requirements that were not previously addressed by Lockheed's proposal, including the addition of an aerial rocket armament subsystem.

On 23 March 1966, the Army awarded Lockheed an engineering and development contract for 10 prototypes, designating the aircraft AH-56A. Initial operating capability was planned for 1972 with an optimistic target of late 1970. Lockheed began construction of the aircraft at its Van Nuys, California facility, and on 3 May 1967, Lockheed held a roll-out ceremony for the AH-56A. The aircraft was christened Cheyenne by the Army. The first flight of the AH-56 occurred on 21 September 1967. The Secretary of Defense approved pre-production funding to support an initial production order for 375 aircraft on 8 January 1968. Manufacture of the 10 Cheyenne prototypes was completed by 1969.

Design

Lockheed designed the Cheyenne as a compound helicopter, which combines a helicopter with fixed-wing features for increased performance, usually speed. The design included features such as a rigid main rotor, low-mounted wings, and a pusher propeller. The Cheyenne was powered by a General Electric T64 turboshaft engine. Thrust was provided by a pusher propeller at the rear of the aircraft. At high speeds, the amount of lift provided by the wings, along with thrust from the pusher prop, reduced the aerodynamic loading of the rotor. At such speeds, the rotor produced up to 20% of the lift, which could be adjusted by collective pitch control changes.[20] Rotor tilt was controlled through gyroscopic precession. The Cheyenne achieved speeds over 200 knots (230 mph, 370 km/h), but as a compound helicopter was unable to qualify for speed records in helicopter categories.

The Cheyenne had a two-seat tandem cockpit featuring an advanced navigation and fire control suite. The tandem seating placed the pilot in the rear seat, and the gunner in the front seat. An unusual feature of the gunner's station was that the entire seat, sighting system, and firing controls rotated to keep the gunner facing the same direction as the gun turret being controlled. The gun-sight afforded the gunner direct viewing from the turret by way of a periscope sight. The pilot had a helmet mounted sight system for aiming weapons.

Weapon turrets were mounted at the nose and the middle of aircraft underbelly. The nose turret could rotate +/- 100° from the aircraft's centerline and could mount either a 40 mm (1.57 in) grenade launcher, or a 7.62 mm (0.308 in) minigun. The belly turret included a 30 mm (1.18 in) automatic cannon with 360° of rotation. Mechanical stops prevented the belly turret from aiming at any part of the helicopter.

Six external hardpoints were located along the bottom of the helicopter, with two under each wing and two on the fuselage under the sponsons. The two inner wing hardpoints could carry pods of three BGM-71 TOW anti-tank missiles. 2.75-inch (70 mm) rockets in 7-rocket or 19-rocket launchers could be carried on the four wing hardpoints. The two fuselage mounts were dedicated to carrying external fuel tanks. The wing hardpoints were also plumbed to allow the carriage of additional fuel tanks if required.

Operational history

Flight testing

Flight testing began with the first flight of the second AH-56 (s/n 66-8827) in September 1967. During early flight tests, a rotor instability issue was discovered when the aircraft was flying at low altitude in ground effect. As the flight envelope was expanded, this instability and other minor problems were discovered and quickly addressed.

Lockheed and the Army held a 13-minute demonstration "first flight" for the public at the Van Nuys Airport on 12 December 1967. During the flight, the Cheyenne demonstrated some of the new capabilities brought about by the thrusting propeller; the helicopter could slow down or accelerate without pitching the nose up or down, as well as being able to pitch the nose down or up at a hover, without causing the aircraft to accelerate forwards or backwards. The Cheyenne demonstrated a stationary hover in a 30-knot (35 mph, 56 km/h) crosswind, and at the end of the flight landed on its two forward landing gear, "bowed" to the audience and then gently set the tail landing gear down as it taxied to parking. By March 1968, the AH-56 had established a flight envelope of 170 knots (196  mph, 315 km/h) in forward flight, 25 knots (29 mph, 46 km/h) sidewards, and 20 knots (23 mph, 37 km/h) rearwards.

The project suffered a setback on 12 March 1969, when the rotor on prototype #3 (s/n 66-8828) struck the fuselage and caused the aircraft to crash, killing the pilot, David A. Beil. The accident occurred on a test flight where the pilot was to manipulate the controls to excite 0.5P oscillations (or half-P hop) in the rotor; 0.5P is a vibration that happens once per two main rotor revolutions, where P is the rotor's rotational speed. The accident investigation noted that safety mechanisms on the controls had apparently been disabled for the flight. The investigation concluded that the pilot-induced oscillations had set up a resonant vibration that exceeded the rotor system's ability to compensate. After the investigation, the rotor and control systems were modified to prevent the same problem from occurring again.

Production contract canceled

The Army issued a cure-notice to Lockheed on 10 April 1969, citing 11 technical problems, and unsatisfactory progress on the program. The main issues were the half-P hop vibration issue, and the aircraft gross weight exceeding program requirements. In response, Lockheed proposed an "improved flight control system" (ICS) to reduce rotor oscillations, and steps for removing excess weight and addressing other minor issues in production helicopters. The Army felt Lockheed's solutions to the cure-notice issues would delay the program and increase costs. Citing Lockheed's inability to meet the production timeline, the Army canceled the AH-56 production contract on 19 May 1969, but retained the development contract in hopes that the issues could be resolved.

In September 1969, Cheyenne prototype #10 (s/n 66-8835) underwent wind tunnel testing at NASA Ames Research Center, to research the half-P hop and drag issues. The engineers did not realize that the fixed mounts used to secure the aircraft in the wind tunnel would not allow the helicopter to move relative to the rotor, as it did in flight. As a result, there was no natural damping of the rotor pitching motion. The remote controllers' lack of sensory feedback from helicopter compounded the situation. During high speed testing to replicate the half-P hop vibration, the rotor oscillations quickly accelerated out of control and struck the tail boom, resulting in the destructive breakup of the helicopter.

Lockheed worked on modifying the AH-56 design to address the vibration and other issues. As a precaution, Cheyenne #9 (s/n 66-8834) was fitted with an ejection seat for the pilot after the March accident. The downward firing ejection seat was placed in the forward seat in place of the gunner's station. This prototype would be used for all remaining envelope expansion flights. Prototype #9 also received an upgraded transmission and drivetrain, and a hinged rear canopy in place of the original sliding canopy around 1970. The new transmission allowed the T64-GE-16 turboshaft engine output to be increased from a derated 3,435 horsepower (2,561 kW) to 3,925 horsepower (2,927 kW). The new canopy eliminated the canopy vibrations.

Cheyenne prototype #6 (s/n 66-8831) began conducting weapons testing at Yuma Proving Ground, Arizona, demonstrating the ability for the gunner and pilot to accurately fire on separate targets on each side on the helicopter. Towards the end of 1970, the Army funded work on TOW missile guidance and night sighting systems. Prototypes #6 and #9 were also tested and evaluated at Yuma Proving Ground from 30 January to 23 December 1971, to determine if stability and control systems were sufficient. Deficiencies were identified in lateral directional stability, uncommanded motion during maneuvering, high vibration, and poor directional control during sidewards flying.

Following the testing at Yuma, prototype #9 received the improved T64-GE-716 engine producing 4,275 shp (3,188 kW) and the planned production version of the ICS system. With these upgrades, the helicopter surpassed its performance requirements. However, under certain conditions stability and control did not completely satisfy the test pilots. Lockheed had studied ways to prevent unstable feedback from the gyro. The solution was to relocate the gyro from the top of the rotor head to below the transmission with flexible connections to the rotor. The pilot's controls were connected to hydraulic servomotors then connected through springs to the gyro. This system prevented rotor vibration forces from transmitting back into the flight controls. It was called the "advanced mechanical control system" (AMCS) and was installed on Cheyenne #7 in 1972 to improve handling and rotor stability.

Program demise

In 1971, political friction increased between the Army and the Air Force over the close air support (CAS) mission. The Air Force asserted that the Cheyenne would infringe on the Air Force's CAS mission in support of the Army, which had been mandated with the Key West Agreement of 1948. The Department of Defense (DOD) conducted a study that concluded that the Air Force's A-X program, the Marine Corps' Harrier, and the Cheyenne were significantly different that they did not constitute a duplication of capabilities. On 22 October 1971, the Senate Armed Services subcommittee on Tactical Air Power conducted hearings to evaluate the CAS mission and the pending programs. The most damaging testimony for the Army's program came from the commander of the Air Force's Tactical Air Command, General William W. Momyer, who cited helicopter casualty statistics of Operation Lam Son 719.

The Army convened a special task force under General Marks in January 1972, to reevaluate the requirements for an attack helicopter. The purpose of the Marks Board was to develop an "updated and defensible" material needs document. The task force conducted flight evaluations of the AH-56, along with two industry alternatives for comparison: the Bell 309 King Cobra and Sikorsky S-67 Blackhawk. Analysis of the three helicopters determined that the Bell and Sikorsky helicopters could not fulfill the Army's requirements.

The Army also conducted a weapons demonstration for the Senate Armed Services Committee in early 1972, to show off the Cheyenne's firepower and garner support for attack helicopter development. The first TOW missile that was fired in the demonstration failed and went into the ground. The second missile was fired and hit the target. Previously, 130 TOW missiles had been fired without failure, but the failure of the first missile was now linked to perception of the aircraft. In April 1972, the Senate published its report on CAS. The report recommended funding of the Air Force's A-X program, which would become the A-10 Thunderbolt II, and limited procurement of the Harrier for the Marine Corps. The report never referred to the Cheyenne by name and only offered a lukewarm recommendation for the Army to continue procurement of attack helicopters, so long as their survivability could be improved.

The Cheyenne program was canceled by the Secretary of the Army on 9 August 1972. The helicopter's large size and inadequate night/all-weather capability were reasons stated by the Army for the cancellation. The Cheyenne's analog and mechanical weapons systems were becoming out of date as new digital systems that were more accurate, faster, and lighter were being developed. The Cheyenne's unit cost had increased and was likely to increase further if new avionics were incorporated.

On 17 August 1972, the Army initiated the Advanced Attack Helicopter (AAH) program. AAH sought an attack helicopter based on combat experience in Vietnam, with a lower top speed of 145 kn (167 mph, 269 km/h) and twin engines for improved survivability. Lockheed offered the CL-1700, a modified version of the Cheyenne with two engines and omitted the pusher propeller, without success. The AAH program led to the AH-64 Apache, which entered service in the mid-1980s.

After the cancellation, the Army conducted an evaluation of the seventh Cheyenne equipped with the AMCS flight control system. The testing showed the AMCS removed most of the remaining control problems, improved stability, improved handling, and decreased the pilot workload. With the AMCS, the Cheyenne reached a speed of 215 kn (247 mph, 398 km/h) in level flight and in a dive achieved 245 kn (282 mph, 454 km/h); it also demonstrated improved maneuverability at high speeds. Prototype #7 was the last Cheyenne to fly. Lockheed had counted on the Cheyenne to establish itself in the helicopter market with its rigid rotor technology, but the ambitious project was unsuccessful. The firm did not pursue development of another helicopter.

Lockheed proposed a civilian version of the Cheyenne as the CL-1026. This would have been a 30-seater helicopter, but the design never made it off the drawing board.

Surviving aircraft:

• No. 2 66-8827 is on display at Fort Polk, Louisiana.
• No. 5 66-8830 is stored at the Army Aviation Museum, Fort Rucker, Alabama.
• No. 6 66-8831 is on display at Fort Campbell.
• No. 7 66-8832 is on display at the Army Aviation Museum, Fort Rucker. No longer on outdoor display.

Specifications (AH-56A)

General characteristics:

• Crew: 2 (pilot in the rear, gunner/co-pilot to the front)
• Length: 54 ft 8 in (16.66 m)
• Height: 13 ft 8.5 in (4.178 m)
• Empty weight: 12,215 lb (5,541 kg)
• Gross weight: 18,300 lb (8,301 kg)
• Max takeoff weight: 25,880 lb (11,739 kg)
• Powerplant: 1 × General Electric T64-GE-16 turboshaft engine, 3,925 shp (2,927 kW)
• Main rotor diameter: 51 ft 3 in (15.62 m)
• Main rotor area: 2,063.2 sq ft (191.68 m2)

• Blade section: - root: NACA (4.6)3012 mod; tip: NACA (0.6)3006 mod
• Rotor systems: 4-bladed main rotor, 4-bladed tail rotor
• Propellers: 3-bladed constant-speed pusher propeller.

Performance:

• Maximum speed: 212 kn (244 mph, 393 km/h)
• Cruise speed: 195 kn (224 mph, 361 km/h)
• Range: 1,063 nmi (1,223 mi, 1,969 km)
• Service ceiling: 20,000 ft (6,100 m)
• Rate of climb: 3,000 ft/min (15 m/s)

Armament:

Guns:

• 1 × nose turret with either a 40 mm (1.575 in) M129 grenade launcher grenade launcher or a 7.62 mm × 51 mm (0.300 in × 2.008 in) XM196 minigun and
• 1 × belly turret with an XM140 30 mm (1.181 in) cannon
• Hardpoints: 6 with provisions to carry combinations of:
• Rockets: 2.75 in (70 mm) FFA rockets
• Missiles: BGM-71 TOW missiles.

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