L’Hawker Tempest, evoluzione del precedente Typhoon, era un cacciabombardiere monoplano e monomotore

L’Hawker Tempest, evoluzione del precedente Typhoon, era un cacciabombardiere monoplano e monomotore progettato dall'azienda aeronautica britannica Hawker Aircraft e impiegato prevalentemente dalla Royal Air Force; realizzato con diverse motorizzazioni, entrò in servizio nel corso della seconda guerra mondiale e rimase nei reparti delle forze aeree di India e Pakistan fino alla seconda metà degli anni cinquanta.

Storia del progetto

Mentre la Hawker e la RAF erano alle prese con i problemi di sviluppo evidenziati dal Typhoon, già nel mese di marzo del 1940 Sydney Camm e la sua squadra considerarono di rielaborarne il progetto concentrandosi in particolare sulla revisione dell'ala, considerata la causa principale delle insoddisfacenti performance in quota del nuovo caccia.

Nel nuovo progetto, che al momento aveva la designazione Hawker P. 1012 (o Typhoon II), venne studiato l'impiego di una nuova ala con profilo a flusso laminare, la stessa soluzione che i tecnici della statunitense North American Aviation stavano considerando per il progetto del loro P-51 Mustang.

Nel caso del P. 1012 il valore del rapporto tra lo spessore e la lunghezza dell'ala era pari al 14,5%, contro il 18% del Typhoon, ed il massimo spessore dell'ala veniva raggiunto in un punto relativamente distante dalla mezzeria della corda alare; la lunghezza dall'ala venne variata nel corso dello sviluppo progettuale: inizialmente più lunga rispetto a quella del Typhoon, in un secondo momento venne sensibilmente accorciata finendo per risultare, al contrario, più corta.

Con queste caratteristiche la nuova ala risultò troppo sottile perché vi potessero trovare posto i serbatoi di carburante, che furono spostati nella fusoliera davanti al pilota; questa modifica consentì, d'altro canto, di spostare nello spessore alare i radiatori per il raffreddamento del previsto motore Sabre IV, con prese d'aria disposte nel bordo d'entrata, in prossimità della radice alare.

Il disegno della pianta dell'ala assunse inoltre una forma ellittica per consentire l'alloggiamento dei quattro cannoni Hispano Mk.II ed ai loro serbatoi da 200 proiettili ciascuno. La nuova forma dell'ala portò Sydney Camm, famoso per il suo tagliente umorismo, ad osservare che "Lo staff dell’aeronautica non avrebbe voluto acquistare niente che non somigliasse a uno Spitfire."

All'inizio dell'autunno del 1941 il progetto del nuovo caccia era sostanzialmente definito e nel mese di ottobre il ministero dell'aria emise la specifica F.10/41, scritta appositamente per poter sottoscrivere, il mese seguente, un contratto per due prototipi del nuovo velivolo. All'epoca l'aereo era ancora identificato come "Typhoon Mark II", ma venne successivamente rinominato Tempest quando era ormai chiaro che le numerose modifiche introdotte avevano infine portato ad un velivolo diverso. A proposito della variazione della denominazione del nuovo aereo le fonti sono in disaccordo tra loro, facendo risalire tale decisione al gennaio 1942, al successivo mese di febbraio o ancora al mese di agosto.

Poco meno di un anno dopo, il 2 settembre del 1942, il primo prototipo del Tempest venne portato in volo per la prima volta, anche se si trattava sostanzialmente di un velivolo "ibrido": con l'obiettivo di accelerare il processo di sviluppo, Camm e la Hawker decisero di utilizzare la nuova ala abbinata alla cellula di un Typhoon, modificata con l'aggiunta del serbatoio davanti al pilota ma ancora equipaggiata con il motore Sabre II ed il radiatore "a mento" nella zona frontale e l'abitacolo con gli sportelli di tipo automobilistico.

Nel frattempo però, sulla scorta dell'esperienza infelice maturata con il progetto del Hawker Tornado, la Hawker aveva previsto soluzioni alternative per la motorizzazione del nuovo caccia: caratterizzati da diversi numeri di modello (Mark, in lingua inglese), furono studiate complessivamente cinque alternative ognuna dotata di un diverso apparato propulsivo.

Pressato dall'urgente necessità di aerei dalle prestazioni sempre migliori, l'Air Ministry aveva emesso già nel mese di agosto (ancor prima del volo del prototipo) un ordine per 400 esemplari di Tempest Mk.I; i problemi riscontrati nella realizzazione del motore Sabre IV ed il conseguente ritardo nella realizzazione della prima variante del Tempest (poi definitivamente abbandonata) condussero a trasformare gli ordini in esemplari della variante Mk.V, il primo dei quali lasciò le catene di montaggio il 21 giugno del 1943.

Lo sviluppo della versione Mk.II fu avviato in parallelo a quello delle Mk.I e Mk.V, raccogliendo l'eredità del Tornado, il cui esemplare noto come "F.18/37C" volò per la prima volta il 23 ottobre del 1941. Il programma tuttavia si protrasse considerevolmente a causa delle iniziali difficoltà incontrate nell'evoluzione del motore Centaurus che si prevedeva di utilizzare come motorizzazione. Problemi di lubrificazione, di surriscaldamento, di infiltrazioni dei gas di scarico, ma soprattutto di vibrazioni ritardarono la messa in produzione del motore, determinando rallentamenti e rinvii anche a carico del Tempest Mk.II.

Nel frattempo i tecnici dell'Hawker furono in grado di visionare un esemplare di Focke-Wulf Fw 190 catturato il 23 giugno 1942, traendone particolare vantaggio nella realizzazione del sistema di raffreddamento dell'olio motore e nella conformazione del sistema di scarico dei gas combusti.

Alla fine di giugno del 1943 il Tempest Mk.II riprese i voli di prova mentre il primo esemplare di serie poté prendere il volo solamente il 4 ottobre del 1944, dopo ulteriori ritardi causati dalla difficoltà di individuare uno stabilimento disponibile per installarvi la catena di montaggio, stanti i considerevoli impegni già assunti dalle aziende del gruppo Hawker per la produzione di altri velivoli.

Tecnica

Cellula

Dal punto di vista strutturale la Hawker sostanzialmente trasferì nel Tempest tutte le soluzioni già impiegate nel Typhoon provvedendo, sulla base delle prime esperienze operative, a irrobustire la struttura del tronco posteriore della fusoliera e a ingrandire le dimensioni dell'impennaggio.

Il carrello d'atterraggio presentava gambe più lunghe, per permettere l'installazione di una nuova elica quadripala dal diametro considerevole, e carreggiata più ampia, al fine di migliorare la stabilità nell'atterraggio ad alte velocità; furono utilizzate anche ruote più sottili, per consentirne la ritrazione all'interno del ridotto spessore delle ali.

In ordine cronologico, la prima variante portata in volo fu la Mk.V, nel settembre del 1942; struttura alare a parte, riprendeva anche esteriormente le linee del Typhoon, per quanto affinate dal punto di vista aerodinamico: in particolare, utilizzando lo stesso motore Sabre II, manteneva il radiatore "a mento" nella parte anteriore della fusoliera, che nel progetto originale si era previsto di eliminare.

Nel mese di febbraio del 1943 venne portato in volo il prototipo della versione Mk.I, come inizialmente previsto equipaggiata con il motore Sabre IV e caratterizzata dallo spostamento nello spessore alare dei pacchi radianti per il raffreddamento del propulsore; contraddistinta dalla forma aerodinamica del muso più affusolata, questa versione presentava una certa somiglianza con lo Spitfire, accentuata dal disegno ellittico della pianta alare.

Considerevole mutamento dell'aspetto esteriore del Tempest si ebbe con la comparsa, alla fine di giugno del 1943, della variante Mk.II equipaggiata con un motore radiale, ma la diversa architettura del propulsore non richiese radicali interventi strutturali sulla cellula dell'aereo che rimase sostanzialmente invariata rispetto alle precedenti versioni.

Motore

Elemento costante nel processo di sviluppo della famiglia Tornado-Typhoon-Tempest fu la difficoltà di reperire un motore potente ed affidabile al tempo stesso: se il fallimento del progetto del motore Rolls-Royce Vulture aveva determinato l'abbandono del caccia Tornado, prima il Typhoon e poi il Tempest si trovarono a convivere con il complesso sviluppo del motore Napier Sabre.

Questo era un motore ad H a ventiquattro cilindri, che venne utilizzato fin dal principio sul Typhoon e che, nella versione "IV" (accreditata di 2 240 hp di potenza, pari a 1 670 kW) avrebbe dovuto equipaggiare anche il Tempest.

Il Sabre IV diede buona prova di sé durante test comparativi svolti nel giugno del 1943 quando, installato sulla versione Mk.I del Tempest (con i radiatori nello spessore alare), fece registrare velocità leggermente superiori a quelle del Tempest Mk.V dotato del collaudato Sabre II ma si dimostrò particolarmente complesso da mettere a punto tanto che la Napier e le autorità britanniche decisero di abbandonarne lo sviluppo, rinunciando di conseguenza anche ad ogni ulteriore sperimentazione riguardante il Tempest Mk.I.

Il Sabre II (2 200 hp, pari a 1 640 kW) equipaggiò i Tempest della versione Mk.V mentre il Sabre VA (2 340 hp, pari a 1 745 kW) fu installato sull'ultima variante del Tempest, la Mk.VI.

Il Tempest fu il primo dei caccia della Hawker a raggiungere la produzione in serie equipaggiato con il motore radiale Bristol Centaurus; questo era un motore a diciotto cilindri, disposti su due file (o "stelle"), caratterizzato dall'impiego di valvole a fodero. Accreditato della potenza di 2 520 hp (1 879 kW) venne adottato sulla variante Mk.II del Tempest al quale garantiva la velocità massima di 440 mph (pari a poco più di 708 km/h).

Nel corso del processo di sviluppo del Tempest vennero studiate anche due varianti equipaggiate con motore Rolls-Royce Griffon: si trattava di un motore dodici cilindri a V di 60° sovralimentato tramite compressore centrifugo il cui impiego sul Tempest non andò oltre la fase sperimentale, anche perché prioritariamente destinato ad equipaggiare le più recenti versioni dello Spitfire.

Armamento

Anche nell'armamento il Tempest riprese inizialmente le stesse dotazioni del Typhoon, alloggiando nello spessore alare quattro cannoni Hispano Mk.II calibro 20 mm, camerati per il munizionamento 20 × 110 mm, caratterizzati esteriormente dalla carenatura che avvolgeva la parte della canna sporgente oltre il bordo d'entrata dell'ala.

Nei primi mesi del 1943 venne messa in produzione la versione Mk.V del cannone Hispano, più leggera e corta della precedente, che risultò adattarsi maggiormente all'ala del Tempest rimanendone completamente all'interno. Gli aerei dotati di questa versione del cannone vennero identificati come Mk.V "Serie 2".

Sotto le ali il più recente caccia di Sydney Camm poteva trasportare bombe fino ad un carico massimo di 2 000 lb (907 kg) o in alternativa serbatoi supplementari di carburante sganciabili. A testimonianza del lavoro di affinamento aerodinamico svolto nel progettare il Tempest, i ganci subalari per le bombe erano ricoperti da apposita carenatura ed i serbatoi supplementari erano a forma di goccia.

Anche nel caso del Tempest, per le missioni di attacco al suolo, trovarono impiego i proiettili a razzo da 3 pollici alloggiati, fino a quattro per ogni semiala, su apposite rotaie agganciate nell'intradosso alare.

Impiego operativo

Secondo le indicazioni fornite dalla Air Fighting Development Unit, unità sotto il controllo del Fighter Command della RAF e del Ministero dell'aria incaricata dello svolgimento di prove comparative al fine di sviluppare e definire tattiche di combattimento efficaci contro il nemico, i primi reparti equipaggiati con il Tempest furono tra quelli che in precedenza avevano già impiegato il Typhoon, al fine di agevolare l'introduzione in servizio del nuovo modello.

Le prime consegne riguardarono gli esemplari della serie Mk.V ed ebbero inizio nel gennaio del 1944; i primi reparti completamente operativi furono il N° 486 (reparto della Royal New Zealand Air Force inquadrato nella RAF) ed il N° 3 Squadron, negli ultimi giorni del mese di aprile. Le prime missioni operative furono le stesse già assegnate ai Typhoon, in particolare contro le linee di rifornimento del nemico, mentre nei rari casi di combattimento aereo il Tempest si dimostrò essere in grado di avere la meglio contro qualsiasi avversario, tanto che alcuni ritengono che solo l'inesperienza dei piloti britannici abbia consentito qualche successo ai Bf 109 ed agli Fw 190 nemici.

L'introduzione del Tempest non fu tuttavia priva di noie: nel giro di un mese ben cinque velivoli andarono perduti per problemi al motore; l'elemento critico fu presto individuato nell'elica che, al raggiungimento di elevate velocità, trascinava con sé senza più controllo l'albero motore provocando una situazione di fuorigiri dagli esiti letali per i cuscinetti e per l'impianto di lubrificazione. In breve il problema venne risolto con l'utilizzo di una diversa elica.

Nei giorni dell'Operazione Overlord i Tempest furono tenuti tra le riserve, nell'attesa della reazione da parte della Luftwaffe contro le truppe appena sbarcate; in breve però, riscontrando che tale minaccia non si era concretizzata, anche i nuovi caccia furono gettati nella mischia facendo registrare già dalla prima uscita, effettuata da nove velivoli del N° 3 Squadron, tre abbattimenti senza subire nessuna perdita.

Dopo una sola settimana dall'inizio dello sbarco, i cieli britannici vennero solcati da un nemico fino ad allora sconosciuto ai più: inizialmente identificate con il nome di "divers" (letteralmente, "tuffatori") le V1 divennero il principale pensiero per la Air Defense of Great Britain che assunse il compito vitale di impedire a questi nuovi ordigni di colpire Londra ed il sud dell'Inghilterra. I Tempest dei due Squadron già operativi, cui presto si aggiunsero il N° 56 ed il N° 501 Squadron, vennero affiancati ai reparti equipaggiati con Spitfire, Mustang e Mosquito per giocare un ruolo di primo piano nel contrastare la prima delle Vergeltungswaffen tedesche.

I piloti dei Tempest, operanti dalla base RAF di Newchurch (nel Kent), poterono alla fine fregiarsi di aver abbattuto più di un terzo di tutte le "bombe volanti" neutralizzate dalla RAF tra il 13 giugno ed il 5 settembre del 1944, aggiudicandosi alla fine 638 abbattimenti (altre fonti, tuttavia, indicano numeri diversi o non forniscono dati specifici).

Le operazioni di contrasto alle bombe volanti ebbero termine quando l'avanzata delle truppe alleate consentì di conquistare i territori sui quali erano state realizzate le rampe di lancio; per un paio di mesi i Mk.V destinati a questo compito furono oggetto di accurata manutenzione ed i loro piloti inviati presso le Operational Training Units per contribuire all'addestramento delle nuove leve. Altri reparti furono invece impiegati intensivamente nel supporto alle truppe di terra ed al conseguimento della supremazia aerea nei cieli d'Europa; in questo frangente i Tempest Mk.V ebbero l'occasione di scontrarsi, ed in alcuni casi avere la meglio, con i Messerschmitt Me 262.

Il 19 aprile del 1945 un Tempest Mk.V del N° 80 Squadron reclamò l'abbattimento di un velivolo fino ad allora sconosciuto, che dalle analisi registrate dalla fotomitragliatrice si rivelò essere un Heinkel He 162; l'ultimo abbattimento di un velivolo da parte di un Tempest fu registrato il 3 maggio successivo. Al termine del conflitto erano complessivamente otto gli Squadron operativi equipaggiati con i Tempest, di cui sette appartenenti alla 2nd Tactical Air Force ed uno alla Air Defense of Great Britain.

Nel dopoguerra la RAF decise di utilizzare il Tempest Mk.V come velivolo standard dei propri reparti da caccia in attesa dell'entrata in servizio dei nuovi de Havilland DH.103 Hornet e dei jet Gloster Meteor e de Havilland DH.100 Vampire; in questo periodo i reparti operativi, ridotti nel numero in ragione della conclusione delle ostilità, non superarono mai le dieci unità, quattro delle quali furono nel frattempo riequipaggiate con i più recenti velivoli della versione Mk.VI.

A partire dall'ottobre del 1944, presso le basi di Aston Down e di Kemble del RAF Maintenance Command (entrambe situate nel Gloucestershire), furono concentrati i nuovi Tempest Mk.II in attesa di essere destinati ai reparti operativi. Già nei primi mesi del 1945, quando fu chiaro che la guerra in Europa stava volgendo al termine, venne presa la decisione di fare della nuova variante del Tempest la punta di diamante della Tiger Force, il reparto che la RAF stava approntando a supporto delle operazioni britanniche per la prevista invasione del Giappone, ed i primi sei esemplari furono inviati in Medio Oriente per lo svolgimento delle prove in ambiente tropicale. La repentina conclusione del conflitto contro il Giappone cambiò drasticamente i progetti della RAF: gli ordini per la produzione dei Tempest Mk.II furono radicalmente ridotti e parte degli aerei già completati utilizzata per costituire il materiale di volo dei N° 183 e N° 247 Squadron, unici reparti ad impiegare in patria i Mk.II.

La maggior parte dei Mk.II, però, ebbe modo di operare al di fuori del territorio metropolitano: equipaggiati con questi aerei, tre Squadron facevano parte della 2nd Tactical Air Force, ridenominata British Air Forces of Occupation (BAFO) ed operante sul territorio tedesco occupato, ed altri tre erano parte della Far East Air Force, basati in India.

Durante un periodo di circa due anni i reparti della RAF operanti in India occasionalmente utilizzarono i loro aerei per operazioni di contrasto al movimento nazionalista ma furono progressivamente sciolti tra il dicembre del 1946 e l'agosto del 1947; con l'indipendenza del paese, tutti i Tempest Mk.II fino ad allora superstiti furono presi in consegna dalla Royal Indian Air Force, che a sua volta ne cedette alcuni alla Royal Pakistan Air Force l'anno successivo. India e Pakistan mantennero in servizio i Tempest Mk.II fino al 1953.

Gli ultimi Tempest Mk.II a rimanere in servizio con il Regno Unito appartenevano al N° 33 Squadron che, dal territorio tedesco, furono trasferiti (ad Hong Kong o a Singapore) nella campagna contro i guerriglieri del Tentera Pembebasan Rakyat Malaya (Esercito di Liberazione Nazionale della Malesia), facendo registrare la loro ultima sortita operativa il 6 giugno del 1951.

Infine, tra il febbraio del 1950 ed il maggio del 1952, numerosi Tempest furono rivisti e trasformati per il traino di bersagli a scopo addestrativo: ottanta esemplari così modificati, ed identificati come TT Mk.5 e TT Mk.6, prestarono servizio presso alcune Armament Practice Stations sia in patria che in Germania.

Impieghi sperimentali

Il Tempest fu utilizzato almeno in due occasioni come banco di prova volante. Nel primo caso vennero sperimentati, impiegando due diversi prototipi, due diversi tipi di radiatore anulare da utilizzare per il motore Napier Sabre VI, uno dei quali adottava anche un'elica semi-intubata; nessuno dei due radiatori superò lo stadio sperimentale.

La seconda occasione riguardò la fase sperimentale dello sviluppo del cannone Vickers P calibro 40 mm o 47 mm. Anche in questa occasione non si giunse alla produzione in serie.

Varianti

I dati sono tratti da "The Hawker Tempest I-VI, in Aircraft Profile, nº 197" se non diversamente indicato:

• Typhoon Mk II: designazione originale dell'Hawker Tempest, identificato anche come P. 1012.
• Tempest Mk I: prototipo equipaggiato con il motore a pistoni Napier Sabre IV. Ne fu realizzato un solo esemplare.
• Tempest Mk II: Caccia monoposto, propulso da un motore radiale a pistoni Bristol Centaurus; ne furono realizzati complessivamente 472 esemplari.
• Tempest FB Mk II: designazione relativa ad esemplari in configurazione caccia-bombardiere: monoposto con piloni subalari per bombe e razzi.
• Tempest Mk III: prototipo equipaggiato con il motore a pistoni Rolls-Royce Griffon IIB; il suo sviluppo evolverà nel successivo Hawker Sea Fury.
• Tempest Mk IV: nuova designazione assegnata al Tempest Mk III rimotorizzato con un motore Rolls-Royce Griffon 61; non venne mai portato in volo.
• Tempest Mk V: caccia o caccia-bombardiere, monoposto, propulso dal motore a pistoni Napier Sabre II.
• Tempest Mk V Series 1: i primi 100 aerei di produzione furono equipaggiati con quattro cannoni Hispano Mark II da 20 mm a canna lunga.
• Tempest Mk V Series 2: gli altri 700 aerei di produzione furono equipaggiati con quattro cannoni Hispano Mark V da 20 mm a canna corta.
• Tempest TT Mk 5: Dopo la fine della seconda guerra mondiale alcuni Tempest Mk V furono convertiti in traino per i bersagli.
• Tempest Mk VI: Caccia monoposto, dotato di motore Sabre V; ne furono costruite 142 unità.
• Tempest TT Mk 6: dopo la fine della seconda guerra mondiale alcuni Tempest Mk VI furono convertiti in traino per i bersagli.

Utilizzatori:

• Canada Royal Canadian Air Force
• India Royal Indian Air Force poi Bhartiya Vāyu Senā
• Nuova Zelanda  No. 486 Squadron RNZAF
• Pakistan Pakistani Fida'iyye
• Regno Unito Royal Air Force.

ENGLISH

The Hawker Tempest is a British fighter aircraft primarily used by the Royal Air Force (RAF) in the Second World War. The Tempest, originally known as the Typhoon II, was an improved derivative of the Hawker Typhoon, intended to address the Typhoon's unexpected deterioration in performance at high altitude by replacing its wing with a thinner laminar flow design. Since it had diverged considerably from the Typhoon, it was renamed Tempest. The Tempest emerged as one of the most powerful fighters of World War II and was the fastest single-engine propeller-driven aircraft of the war at low altitude.

Upon entering service in 1944, the Tempest was used as a low-level interceptor, particularly against the V-1 flying bomb threat, and as a ground attack platform, in which it supported major events such as Operation Market Garden. Later, it successfully targeted the rail infrastructure in Germany and Luftwaffe aircraft on the ground, as well as countering such attacks by German fighters. The Tempest was effective in the low-level interception role, including against newly developed jet-propelled aircraft such as the Messerschmitt Me 262.

The further-developed Tempest II did not enter service until after the end of hostilities. It had several improvements, including being tropicalised for combat against Japan in South-East Asia as part of the Commonwealth Tiger Force.

Design and development

Origins

During development of the earlier Hawker Typhoon, the design team, under the leadership of Sydney Camm, had already planned out a series of design improvements; these improvements cumulated in the Hawker P. 1012, otherwise known as the Typhoon II or Thin-Wing Typhoon. Although the Typhoon was generally considered to be a good design, Camm and his design team were disappointed with the performance of its wing, which had proved to be too thick in its cross section, and thus created airflow problems which inhibited flight performance, especially at higher altitudes and speeds where it was affected by compressibility. The Typhoon's wing, which used a NACA 4 digit series wing section, had a maximum thickness-to-chord ratio of 19.5 per cent (root) to 12 per cent (tip), in comparison to the Supermarine Spitfire's 13.2 per cent tapering to 6 per cent at the tip, the thinner design being deliberately chosen to reduce drag. In addition, there had been other issues experienced with the Typhoon, such as engine unreliability, insufficient structural integrity, and the inability to perform high altitude interception duties.

In March 1940, engineers were assigned to investigate the new low–drag laminar flow wing developed by NACA in the United States, which was later used in the North American P-51 Mustang. A laminar flow wing adopted for the Tempest series had a maximum thickness-to-chord ratio of 14.5 per cent at the root, tapering to 10 per cent at the tip. The maximum thickness of the Tempest wing was set further back at 37.5 per cent of the chord versus 30 per cent for the Typhoon's wing, reducing the thickness of the wing root by five inches on the new design. The wingspan was originally greater than that of the Typhoon at 43 ft (13.1 m), but the wingtips were later "clipped" and the wing became shorter; 41 ft (12.5 m) versus 41 ft 7 in (12.7 m).

The wing planform was changed to a near-elliptical shape to accommodate the 800 rounds of ammunition for the four 20 mm Hispano cannons, which were moved back further into the wing. The new wing had greater area than the Typhoon's, however, the new wing design sacrificed the leading edge fuel tanks of the Typhoon: to make up for this loss in capacity, Hawker engineers added a new 21 in (53 cm) fuel bay in front of the cockpit, with a 76 Igal (345 l) fuel tank. In addition, two inter-spar wing tanks, each of 28 Igal (127 l), were fitted on either side of the centre section and, starting with late model Tempest Vs, a 30 Igal (136 l) tank was carried in the leading edge of the port wingroot, giving the Tempest a total internal fuel capacity of 162 Igal (736 l).

Another important feature of the new wing was Camm's proposal that the radiators for cooling the engine be fitted into the leading edge of the wing inboard of the undercarriage. This eliminated the distinctive "chin" radiator of the Typhoon and improved aerodynamics. A further improvement of the Tempest wing over that of the Typhoon was the exceptional, flush-riveted surface finish, essential on a high performance laminar flow airfoil. The new wing and airfoil, and the use of a four-bladed propeller, acted to eliminate the high frequency vibrations that had plagued the Typhoon. The design team also chose to adopt the new Napier Sabre IV engine for the Tempest, drawings of which had become available to Hawker in early 1941.

In February 1941, Camm commenced a series of discussions with officials within the Ministry of Aircraft Production on the topic of the P.1012. In March 1941 of that year, clearance to proceed with development of the design, referred to at this point as the Typhoon II, was granted. At this point, work was undertaken by a team of 45 draughtsmen at Hawker's wartime experimental design office at Claremont, Esher to convert the proposal into technical schematics from which to commence manufacture. In March 1941, the Air Ministry issued specification F.10/41 that had been written to fit the aircraft. By October 1941, development of the proposal had advanced to the point where the new design was finalised.

Prototypes

On 18 November 1941, a contract was issued by the Air Ministry for a pair of prototypes of the "Typhoon Mark II"; the new fighter was renamed "Tempest" on 28 February 1942. Complications were added to the Tempest program by external factors in the form of engine issues: the Rolls-Royce Vulture engine and corresponding Hawker Tornado aircraft which was being developed in parallel were both terminated. Due to this previous experience on other programs, the Air Ministry was sufficiently motivated to request that a total of six Tempest prototypes be built using different engines so that, if a delay hit one engine, an alternative powerplant would already be available.[11] This measure turned out to be prudent, as engine development was not trouble-free on some of the variants of the Tempest.

The six prototypes were built as a single Mk.I, HM599, powered by a Sabre IV, two Mk.IIs (LA602 and LA607) equipped with the Centaurus IV, a Mk.III (LA610) with a Griffon IIB, a Mk.IV (LA614) with a Griffon 61, and a Mk.V (HM595) with the Sabre II. The Tempest Mk.I featured other new features, such as a clean single-piece sliding canopy in place of the car-door framed canopy, and it used wing radiators instead of the "chin" radiator. Due to development difficulties with the Sabre IV engine and its wing radiators, the completion of the Mk.I prototype, HM599, was delayed, and thus it was the Mk.V prototype, HM595, that would fly first.

On 2 September 1942, the Tempest Mk.V prototype, HM595, conducted its maiden flight, flown by Philip Lucas from Langley, Berkshire, England. HM595, which was powered by a Sabre II engine, retained the Typhoon's framed canopy and car-style door, and was fitted with the "chin" radiator, similar to that of the Typhoon. It was quickly fitted with the same bubble canopy fitted to Typhoons, and a modified fin that almost doubled the vertical tail surface area, made necessary because the directional stability with the original Typhoon fin had been reduced over that of the Typhoon by the longer nose incurred by the new fuel tank. The horizontal tailplanes and elevators were also increased in span and chord; these were also fitted to late production Typhoons. Test pilots found the Tempest a great improvement over the Typhoon in performance; in February 1943 the pilots from the A&AEE at Boscombe Down reported that they were impressed by "a manoeuvrable and pleasant aircraft to fly with no major handling faults".

On 24 February 1943, the second prototype HM599 first flew, representing the "Tempest Mk.I" equipped with the Napier Sabre IV engine; this flight had been principally delayed by protracted problems and slippages encountered in the development of the new Sabre IV engine. HM599 was at first equipped with the older Typhoon cockpit structure and vertical tailplane. The elimination of the "chin" radiator did much to improve overall performance, leading to the Tempest Mk.I quickly becoming the fastest aircraft that Hawker had built at that time, having attained a speed of 466 mph (750 km/h) during test flights.

On 27 November 1944, the Tempest Mk.III prototype, LA610, conducted its first flight; it was decided to discontinue development work on the Mk.III, this was due to priority for the Griffon engine having been assigned to the Spitfire instead. Work on the Tempest Mk.IV variant was abandoned without any prototype being flown at all. The Tempest Mk.II, which was subject to repeated delays due to its Centaurus powerplant, was persisted with, but would not reach production in time to see service during the Second World War. Continual problems with the Sabre IV meant that only the single Tempest Mk.I (HM599) was built; consequently, Hawker proceeded to take the Sabre II-equipped "Tempest V" into production instead.

In August 1942, even before the first flight of the prototype Tempest V had been conducted, a production order for 400 Tempests was placed by the Air Ministry. This order was split, with the initial batch of 100 being Tempest V "Series I"s, powered by the 2,235 hp (1,491 kW) Sabre IIA series engine, which had the distinctive chin radiator, while the rest were to have been produced as the Tempest I, equipped with the Sabre IV and leading-edge radiators. These 300 Tempest Is were intended to replace an order for a similar quantity of Typhoons for the Gloster Aircraft Company. As it transpired, the difficulties with the Sabre IV and the wing radiators led to this version never reaching production, the corresponding order was switched to 300 Tempest V "Series 2"s instead.

Tempest Mk.V

During early 1943, a production line for the Tempest Mk. V was established in Hawker's Langley facility, alongside the existing manufacturing line for the Hawker Hurricane. Production was initially slow, claimed to be due to issues encountered with the rear spar. On 21 June 1943, the first production Tempest V, JN729, rolled off the production line and its maiden flight was conducted by test pilot Bill Humble. Several early production aircraft were used for experimental purposes; a number of these underwent extensive service trials at Boscombe Down including clearances to be fitted with external stores, including 500 lb (227 kg) and 1,000 lb (454 kg) bombs and 3 in (76.2 mm) RP-3 rockets, although few Tempest Vs deployed such ordnance operationally during the War. On 8 April 1944, the Tempest V attained general clearance.

During production of the first batch of 100 Tempest V "Series Is", distinguishable by their serial number prefix JNxxx, several improvements were progressively introduced and were used from the outset on all succeeding Tempest V "Series 2s", with serial number prefixes EJ, NV and SN. The fuselage/empennage joint originally featured 20 external reinforcing "fishplates", similar to those fitted to the Typhoon, but it was not long before the rear fuselage was strengthened and, with the fishplates no longer being needed, the rear fuselage became detachable. The first series of Tempest Vs used a built-up rear spar pick-up/bulkhead assembly (just behind the cockpit) which was adapted from the Typhoon. Small blisters on the upper rear wing root fairing covered the securing bolts. This was later changed to a new forged, lightweight assembly which connected to new spar booms: the upper wing root blisters were replaced by small "teardrop" fairings under the wings.

The first 100 Tempest Vs were fitted with 20 mm (.79 in) Hispano Mk.IIs with long barrels which projected ahead of the wing leading edges and were covered by short fairings; later production Tempest Vs switched to the short-barrelled Hispano Mk.Vs, with muzzles flush with the leading edges. Early Tempest Vs used Typhoon-style 34 by 11 inch (83.4 by 28 cm) five-spoke wheels, but most had smaller 30 by 9 inch (76.2 by 22.9 cm) four-spoke wheels. The new spar structure of the Tempest V also allowed up to 2,000 lb (907 kg) of external stores to be carried underneath the wings.

As in all mass-produced aircraft, there may have been some overlap of these features as new components became available. In mid-to-late 1944 other features were introduced to both the Typhoon and Tempest: A Rebecca transponder unit was fitted, with the associated aerial appearing under the portside centre section. A small, elongated oval static port appeared on the rear starboard fuselage, just above the red centre spot of the fuselage roundel. This was apparently used to measure the aircraft's altitude more accurately.

Unusually, in spite of the Tempest V being the RAF's best low- to medium-altitude fighter, it was not equipped with the new Mk.IIC gyroscopic gunsight (as fitted in RAF Spitfires and Mustangs from mid-1944), which would have considerably improved the chances of shooting down opposing aircraft. Tempest pilots continued to use either the Type I Mk.III reflector gunsight, which projected the sighting graticule directly onto the windscreen, or the Mk.IIL until just after the Second World War, when the gyro gunsight was introduced in Tempest IIs.

Two Tempest Vs, EJ518 and NV768, were fitted with Napier Sabre Vs and experimented with several different Napier-made annular radiators, with which they resembled Tempest IIs. This configuration proved to generate less drag than the standard "chin" radiator, contributing to an improvement in the maximum speed of some 11 to 14 mph. NV768 was later fitted with a ducted spinner, similar to that fitted to the Fw 190 V1. Another experimental Tempest V was SN354, which was fitted with a Vickers 47 mm "P" anti-tank gun, under development but never deployed, under each wing in a long “pod".

Tempest II

As a result of the termination of the Tornado project, Sydney Camm and his design team transferred the alternative engine proposals for the Tornado to the more advanced Tempest. Thus, it was designed from the outset to use the Bristol Centaurus 18 cylinder radial engine as an alternative to the liquid cooled engines which were also proposed. A pair of Centaurus-powered Tempest II prototypes were completed. Apart from the new engine and cowling, the Tempest II prototypes were similar to early series Tempest Vs. The Centaurus engine was closely cowled and the exhaust stacks grouped behind and to either side of the engine: to the rear were air outlets with automatic sliding "gills". The carburettor air intakes were in the inner leading edges of both wings, an oil cooler and air intake were present in the inner starboard wing. The engine installation owed much to examinations of a captured Focke-Wulf Fw 190, and was clean and effective.

On 28 June 1943, the first Tempest II, LA602, flew powered by a Centaurus IV (2,520 hp/1,879 kW) driving a four-blade propeller. LA602 initially flew with a Typhoon-type fin and rudder unit. This was followed by the second, LA607, which was completed with the enlarged dorsal fin and first flew on 18 September 1943: LA607 was assigned to engine development. The first major problem experienced during the first few flights was serious engine vibrations, which were cured by replacing the rigid, eight-point engine mountings with six-point rubber-packed shock mounts. In a further attempt to alleviate engine vibration, the four blade propeller was replaced with a five blade unit; eventually, a finely balanced four bladed unit was settled on. Problems were also experienced with engine overheating, poor crankshaft lubrication, exhaust malfunctions and reduction-gear seizures. Because of these problems, and because of the decision to "tropicalise" all Tempest IIs for service in the South-East Asian theatre, production was delayed.

Orders had been placed as early as September 1942 for 500 Tempest IIs to be built by Gloster but in 1943, because of priority being given to the Typhoon, a production contract of 330 Tempest IIs was allocated instead to Bristol, while Hawker were to build 1,800. This switch delayed production even more. On 4 October 1944, the first Tempest II was rolled off the line; the first six production aircraft soon joined the two prototypes for extensive trials and tests. With the end of the Second World War in sight, orders for the Tempest II were trimmed or cancelled; after 50 Tempest IIs had been built at Bristol's Banwell facility, production was stopped and shifted back to Hawker, which built a total of 402, in two production batches: 100 were built as fighters, and 302 were built as fighter-bombers (FB II) with reinforced wings and wing racks capable of carrying bombs of up to 1,000 lb.

Physically, the Tempest II was longer than the Tempest Mk.V (34 ft 5 in/10.5 m versus 33 ft 8 in/10.3 m) and 3 in (76 mm) lower. The weight of the heavier Centaurus engine (2,695 lb/1,222 kg versus 2,360 lb/1,070 kg) was offset by the absence of a heavy radiator unit, so that the Tempest II was only some 20 lb (9 kg) heavier overall. Performance was improved; maximum speed was 442 mph (711 km/h) at 15,200 ft (4,633 m) and climb rate to the same altitude took four and a half minutes compared with five minutes for the Tempest Mk. V; the service ceiling was also increased to 37,500 ft (11,430 m).

Tropicalising measures included the installation of an air filter and intake in the upper forward fuselage, just behind the engine cowling, and the replacement of the L-shaped pitot head under the outer port wing by a straight rod projecting from the port outer wing leading edge. All production aircraft were powered by a (2,590 hp/1,932 kW) Centaurus V driving a 12 ft 9 inch (3.89 m) diameter Rotol propeller. Tempest IIs produced during the war were intended for combat against Japan and would have formed part of Tiger Force, a proposed British Commonwealth long-range bomber force based on Okinawa. The Pacific War ended before they could be deployed.

Tempest Mk.VI

Various engineering refinements that had gone into the Tempest II were incorporated into the last Tempest variant, designated as the Tempest VI. This variant was furnished with a Napier Sabre V engine with 2,340 hp (1,700 kW). The more powerful Sabre V required a bigger radiator which displaced the oil cooler and carburettor air intake from the radiator's centre; air for the carburettor was drawn through intakes on the leading edge of the inner wings, while the oil cooler was located behind the radiator. Most Tempest VIs were tropicalised, the main feature of this process being an air filter which was fitted in a fairing on the lower centre section. Other changes included the strengthening of the rear spar and the inclusion of spring tabs, which granted the variant superior handling performance.

The original Tempest V prototype, HM595, was extensively modified to serve as the Tempest VI prototype. On 9 May 1944, HM595 made its first flight after its rebuild, flown by Bill Humble. In December 1944, HM595 was dispatched to Khartoum, Egypt to conduct a series of tropical trials. During 1945, a further two Tempest V aircraft, EJ841 and JN750, were converted to the Tempest VI standard in order to participate in service trials at RAF Boscombe Down.

At one point, 250 Tempest VIs were on order for the RAF; however, the end of the war led to many aircraft programs being cut back intensively, leading to only 142 aircraft being completed. For a long time, it was thought there were Tempest VIs that had been converted for target towing purposes; however, none of the service histories of the aircraft show such conversions and no supporting photographic evidence has been found. The Tempest VI holds the distinction of being the last piston-engined fighter in operational service with the RAF, having been superseded by jet propelled aircraft.

Drawing board designs

In 1944, in response to the issuing of Air Ministry Specification F.13/44, which sought a long-range fighter equipped with the Rolls Royce R.46 engine, Sydney Camm initiated work on a new design, designated as the P.1027. This was essentially a slightly enlarged Tempest which was powered by the R.46 engine, which was projected to develop around 2,500–4,000 hp (1,864–2,983 kW). This engine would have driven a set of eight-bladed contra-rotating propellers. The radiator was relocated into a ventral bath set underneath the rear fuselage and wing centre section: the wingspan was 41 ft (12.5 m) and the length was 37 ft 3 in (11.4 m).

However, work upon the P.1027 design was soon dropped in favour of concentrating upon a further developed design, designated as the P.1030. It featured wing leading edge radiators and had larger overall dimensions of 42 ft (12.8 m) wingspan and 39 ft 9 in (12.1 m) length. The top speed was expected to be in the region of 508 mph (817 km/h), with a rate of climb of 6,400 ft/min (1,951 m/min). Service ceiling was projected to be 42,000 ft (12,802 m). Work on both tenders was ultimately dropped when Camm decided to focus design efforts upon the more promising jet engine designs he was working on instead.

Design

The Tempest was a single engine fighter aircraft that excelled at low-level flight. In service, its primary role soon developed into performing "armed reconnaissance" operations, often deep behind enemy lines. The Tempest was particularly well suited to the role because of its high speed at low to medium altitudes, its long range when equipped with two 45-gallon drop tanks, the good firepower of the four 20mm cannon and the good pilot visibility. The three-piece windscreen and side windows of the Tempest had directly benefited from examination of captured Focke-Wulf Fw 190s, improvements included the careful design and positioning of the frame structure, blind spots being reduced to an absolute minimum. It had a bullet-resistant centre panel made up of two layers, the outer 1.5 in (38 mm) thick and the inner 0.25 in (6.5 mm).

The majority of production Tempests were powered by a single high-powered Napier Sabre II 24-cylinder engine. All versions of the Sabre drove either a four-bladed, 14 ft (4.267 m) diameter de Havilland Hydromatic or Rotol propeller. Starting with EJxxx series, on the Tempest V, both the improved Sabre IIB and IIC were used, these engines were capable of producing over 2,400 hp (1,789 kW) on emergency boost for short periods of time. Alternative engines were used on some production variants, such as the Tempest II, for which a single Bristol Centaurus 18 cylinder radial engine was adopted, or the final Tempest VI, upon which a Napier Sabre V was used. Early on in development, the adoption of several other engines was proposed, some of which were tested upon multiple prototypes.

The wing of the Tempest was one of its more significant design features, having been developed from the Typhoon to use a thinner laminar flow design approach. The wing planform was of a near-elliptical shape; the aircraft's armament of four 20 mm Hispano cannons with 800 rounds of ammunition was also embedded into the wing.[5] The ailerons were fitted with spring-loaded tabs which lightened the aerodynamic loads, making them easier for the pilot to use and dramatically improving the roll rate above 250 mph (402 km/h). The spar structure of the Tempest V also allowed the wings to carry up to 2,000 lb (907 kg) of external stores. Also developed specifically for the Tempest by Hawker was a streamlined 45 gal (205 l) "drop tank" to extend the operational radius by 500 mi (805 km) and carrier fairing; the redesigned wing incorporated the plumbing for these tanks, one to each wing.

The main undercarriage was redesigned from the Typhoon, featuring lengthened legs and a wider track (16 ft/4.9 m) to improve stability at the high landing speed of 110 mph (177 km/h), and to allow tip clearance for a new de Havilland 14 ft (4.26 m) diameter four-blade propeller. The main undercarriage units were Dowty levered suspension units incorporating trunnions which shortened the legs as they retracted. The retractable tailwheel was fully enclosed by small doors and could be fitted with either a plain Dunlop manufactured tyre, or a Dunlop-Marstrand "twin-contact" anti-shimmy tyre.

During development, Camm and the Hawker design team had placed a high priority on making the Tempest easily accessible to both air and ground crews; to this end, the forward fuselage and cockpit areas of the earlier Hurricane and the Tempest and Typhoon families were covered by large removable panels providing access to as many components as possible, including flight controls and engine accessories. Both upper wing roots incorporated panels of non-slip coating. For the pilot a retractable foot stirrup under the starboard root trailing edge was linked to a pair of handholds which were covered by spring-loaded flaps. Through a system of linkages, when the canopy was open the stirrup was lowered and the flaps opened, providing easy access to the cockpit; as the canopy was closed, the stirrup was raised into the fuselage and the flaps snapped shut.

Operational history

Combat

By April 1944, the Tempest V had attained general acceptance and was in the hands of operational squadrons; 3 Squadron was the first to be fully equipped, closely followed by 486 (NZ) Squadron (the only Article XV squadron to be equipped with the Tempest during the Second World War), replacing their previous Typhoons. A third unit—56 Squadron—initially kept its Typhoons and was then temporarily equipped with Spitfire IXs until sufficient supplies of Tempests were available. By the end of April 1944, these units were based at RAF Newchurch in Kent a new "Advanced Landing Ground" (ALG), where they formed 150 Wing, commanded by Wing Commander Roland Beamont. The new Wing was part of the Second Tactical Air Force (2nd TAF).

Most of the operations carried out by 150 Wing comprised high-altitude fighter sweeps, offensive operations known as "Rangers", as well as reconnaissance missions. Prior to the Normandy landings, Tempests would routinely conduct long-range sorties inside enemy territory and penetrate into Northern France and the Low Countries, using a combination of cannons and bombs to attack airfields, radar installations, ground vehicles, coastal shipping and the launch sites for the German V-1 flying bombs. The build-up of Tempest-equipped squadrons was increased rapidly, in part due to factors such as the V-1 threat, although a labour strike in Hawker's assembly shop adversely affected this rate; by September 1944, a total of five frontline Tempest squadrons which comprised 114 aircraft were in operation.

In June 1944, the first of the V-1s were launched against London; the excellent low-altitude performance of the Tempest made it one of the preferred tools for handling the small fast-flying unmanned missiles. 150 Wing was transferred back to the RAF Fighter Command; the Tempest squadrons soon racked up a considerable percentage of the total RAF kills of the flying bombs (638 of a total of 1,846 destroyed by aircraft). Using external drop tanks, the Tempest was able to maintain standing patrols of 4.5 hours off the south coast of England in the approach paths of the V-1s. Guided by close instructions from coastal radar installation, Tempests would be positioned ready for a typical pursuit and would either use cannon fire or nudge the V-1 with the aircraft itself to destroy it.

In September 1944, Tempest units, based at forward airfields in England, supported Operation Market Garden, the airborne attempt to seize a bridgehead over the Rhine. On 21 September 1944, as the V-1 threat had receded, the Tempest squadrons were redeployed to the 2nd TAF, effectively trading places with the Mustang III squadrons of 122 Wing, which became part of the Fighter Command units deployed on bomber escort duties. 122 Wing now consisted of 3 Sqn., 56 Sqn., 80 Sqn., 274 Sqn. (to March 1945), and 486(NZ)Sqn. From 1 October 1944 122 Wing was based at B.80 Volkel Air Base near Uden, in the Netherlands. During the early phase of operations, the Tempest regularly emerged victorious and proved to be a difficult opponent for the Luftwaffe's Bf 109G and Fw 190 fighters to counter.

Armed reconnaissance missions were usually flown by two sections (eight aircraft), flying in finger-four formations, which would cross the front lines at altitudes of 7,000 to 8,000 feet: once the Tempests reached their allocated target area the lead section dropped to 4,000 feet or lower to search for targets to strafe, while the other section flew cover 1,000 feet higher and down sun. After the first section had carried out several attacks, it swapped places with the second section and the attacks continued until all ammunition had been exhausted, after which the Tempests would return to base at 8,000 ft. As many of the more profitable targets were usually some 250 miles from base, the Tempests typically carried two 45-gallon drop tanks which were turned on soon after takeoff. Although there were fears that the empty tanks would explode if hit by flak, the threat never eventuated and, due to the tanks being often difficult to jettison, they were routinely carried throughout an operation with little effect on performance, reducing maximum speed by 5 to 10 mph and range by 2 per cent.

Between October and December 1944, the Tempest was practically withdrawn from combat operations for overhaul work, as well as to allow operational pilots to train newcomers. The overhaul process involved the replacement or major servicing of their engines and the withdrawal of the limited number of aircraft which were equipped with spring-tabs; these increased manoeuvrability so much that there was a risk of damaging the airframe. In December 1944, upon the Tempest's reentry into service, the type had the twin tasks of the systematic destruction of the North German rail network along with all related targets of opportunity, and the maintenance of air supremacy within the North German theatre, searching for and destroying any high performance fighter or bomber aircraft of the Luftwaffe, whether in the air or on the ground.

In December 1944, a total of 52 German fighters were downed, 89 trains and countless military vehicles were destroyed, for the loss of 20 Tempests. Following the Luftwaffe's Unternehmen Bodenplatte of 1 January 1945, 122 Wing bore the brunt of low- to medium-altitude fighter operations for the Second Tactical Air Force, which had fortuitously escaped being a victim of the extensive Bodenplatte raid, and had contributed to efforts to intercept the raiders. During this time, Spitfire XIVs of 125 and 126 Wings often provided medium- to high-altitude cover for the Tempests, which came under intense pressure, the wing losing 47 pilots in January. In February 1945, 33 and 222 Sqns. of 135 Wing converted from Spitfire Mk IXs and, in March, were joined by 274 Sqn. 135 Wing was based at B.77 Gilze-Rijen airfield in the Netherlands. The intensity of operations persisted throughout the remainder of the war.

Flying a Tempest, French ace Pierre Clostermann claimed the first Allied combat encounter with a Dornier 335 in April 1945. In his book The Big Show he describes leading a flight of Hawker Tempests from No. 3 Squadron RAF over northern Germany, when they saw a lone unusual looking aircraft flying at maximum speed at treetop level. Detecting the British aircraft, the German pilot reversed course to evade. Despite the Tempests' considerable low altitude speed, Clostermann decided not to attempt to follow as it was obviously much quicker though one of the other two Tempests did pursue it briefly.

During 1945, a noteworthy accomplishment of the Tempest was the scoring of a number of kills against the new German jets, including the Messerschmitt Me 262. Hubert Lange, a Me 262 pilot, said: "the Messerschmitt Me 262's most dangerous opponent was the British Hawker Tempest — extremely fast at low altitudes, highly manoeuvrable and heavily armed."

Some Me 262s were destroyed using a tactic known to 135 Wing as the "Rat Scramble"; Tempests on immediate alert took off when an Me 262 was reported to be airborne. They did not directly intercept the jet, but instead flew towards the Me 262 and Ar 234 base at Rheine-Hopsten. The aim was to attack jets on their landing approach, when they were at their most vulnerable, travelling slowly, with flaps down and incapable of rapid acceleration. The Germans responded by creating a "flak lane" of over 150 of the Flakvierling quadruple 20 mm (.79 in) AA batteries at Rheine-Hopsten, to protect the approaches. After seven Tempests were lost to anti-aircraft fire at Rheine-Hopsten in a single week, the "Rat Scramble" was discontinued. For a while, in March 1945, a strict "No, repeat, No ground attacks" policy was imposed; this only applied for a few days.

In air-to-air combat, the Tempest units achieved an estimated air combat success ratio of 7:1 (most of these "victories" were against the unmanned V-1 flying bomb), accomplishing a 2:1 ratio against the single-seat fighters of the depleted Luftwaffe. The top-scoring Tempest pilot was Squadron Leader David C. "Foobs" Fairbanks DFC, an American who joined the Royal Canadian Air Force in 1941. By mid-1944, he was flying with 274 Squadron. When he was shot down and made a POW in February 1945, he had destroyed 11 or 12 German aircraft (and one shared), to make him the highest-scoring Tempest ace.

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