The Bell P-39 Airacobra was a World War II-era fighter aircraft developed by Bell Aircraft for the United States Army Air Forces.
It stood among the primary American fighters at the onset of U.S. involvement in the war.
Notably, the P-39 saw extensive service with the Soviet Air Force, which achieved the highest number of aerial victories attributed to any U.S.-built fighter in any conflict.
Operators of the P-39
United States Army Air Corps / United States Army Air Forces
Early Combat Deployment
Pacific Theater
First combat use by USAAF was in New Guinea in 1942, supporting General MacArthur’s defense of Australia.
Used extensively in the Southwest Pacific for ground attack and close air support.
Aleutian Campaign
Operated in harsh conditions against Japanese forces in Alaska, where low-altitude performance was advantageous.
Tactical Role and Limitations
Strengths
Excellent low-altitude maneuverability.
Heavy firepower ideal for ground attack.
Weaknesses
No turbo-supercharger, limiting high-altitude performance.
Vulnerable in air-to-air combat against Axis fighters like the Bf 109 and A6M Zero.
Units and Missions
Fighter Groups
8th, 35th, 36th, and 37th Fighter Groups operated P-39s in various theaters.
Roles
Ground attack
Reconnaissance
Fighter-bomber missions
Training
Widely used as an advanced trainer in the continental U.S. after frontline withdrawal.
Withdrawal and Legacy
Replaced By
P-38 Lightning, P-47 Thunderbolt, and P-51 Mustang in frontline roles.
Postwar Use
Phased out by 1945; some aircraft transferred to Allied nations or scrapped.
Legacy
Though overshadowed by later fighters, the P-39 was a critical stepping stone in USAAF fighter development and pilot training.
Strategic Impact
The P-39 Airacobra was not the dominant air superiority fighter the USAAF hoped for, but it filled essential roles in early war operations and helped train thousands of American pilots.
Italian Co-Belligerent Air Force
Acquisition and Deployment
After the September 1943 armistice, Italy joined the Allies.
The newly formed ICBAF was equipped with Allied aircraft under Lend-Lease.
Aircraft Received
Around 170 P-39s, mostly P-39N and P-39Q variants, were transferred from USAAF stocks.
Units
The aircraft were assigned to fighter groups including the 4° Stormo and 12° Gruppo, operating from bases in southern Italy.
Operational Role
Mission Types
Tactical ground attack
Armed reconnaissance
Air defense of liberated Italian territory
Combat Use
The Airacobras flew limited combat missions against German forces retreating through the Balkans and northern Italy.
Performance
The aircraft’s low-altitude strengths suited Mediterranean operations, though its limited range and altitude ceiling remained drawbacks.
Technical Notes
Variants
P-39N
Lighter, with reduced fuel capacity (87 gallons), though kits allowed expansion to 120 gallons.
P-39Q
Featured underwing .50 cal gun pods and improved armor.
Modifications
Some aircraft were adapted for reconnaissance or stripped for weight reduction to improve agility.
Withdrawal and Legacy
End of Service
By late 1945, the Airacobras were phased out in favor of more modern aircraft like the Spitfire and P-47 Thunderbolt.
Legacy
Though not a game-changer, the P-39 gave Italy a capable fighter during its re-entry into Allied operations and helped rebuild its air force infrastructure.
The Remaining 102 aircraft survivors of the Second World War were operated by the newly formed Italian Air Force well into the 1950s.
Strategic Impact
The Airacobra’s deployment marked Italy’s transition from Axis collaborator to Allied contributor.
It provided valuable tactical support and training capacity during a critical rebuilding phase, despite its limitations.
The Free French Air Forces
Acquisition and Deployment
Variants Used
P-39N and P-39Q models.
Timeframe
Mid-1943 to late 1944.
Location
Based in North Africa, particularly Algeria and Morocco, under Allied command.
Role and Missions
Primary Role
Tactical fighter and ground attack missions.
Combat Use
Limited combat operations due to the aircraft’s declining relevance and the arrival of more capable fighters.
Performance
The Airacobra’s strengths at low altitude suited the North African terrain, but its short range and poor high-altitude performance were persistent drawbacks.
Replacement and Withdrawal
Replaced By Republic P-47 Thunderbolt fighters, which offered superior range, firepower, and altitude performance.
End of Service
By late 1944, most French-operated P-39s were phased out in favor of newer aircraft as Free French forces integrated more closely with Allied air operations.
Strategic Context
The use of P-39s by Free French forces reflected the broader Lend-Lease strategy, supplying Allied nations with American aircraft.
While not a standout in French service, the Airacobra helped bridge the gap until more advanced fighters became available.
Summary
The Free French Air Forces operated the P-39 Airacobra briefly and in limited numbers, primarily for tactical missions in North Africa.
Its operational impact was modest, and it was quickly replaced by more capable aircraft like the P-47 Thunderbolt.
The Polish Air Force
The Polish Air Force operated only one Bell P-39 Airacobra during World War II, and it was not part of any combat unit.
Instead, it served as the personal aircraft of Soviet General Fyodor Petrovich Polynin, who commanded the Polish “People’s” Air Force from October 1944 to May 1947.
Cultural Impact
The aircraft became a symbol of Soviet influence over postwar Polish military aviation, remembered more for its political associations than operational significance.
Strategic Context
This Airacobra was never part of a Polish combat unit.
Its presence reflected the Soviet Union’s control over Polish military structures during the transition from wartime to communist governance.
It remains a unique footnote in Polish aviation history.
Portugal’s Aeronáutica Militar
Origins and Acquisition
Portugal remained officially neutral during WWII but received several aircraft through internment and postwar purchase.
Initial Aircraft
The first P-39 to arrive was a P-400 (export variant of the P-39D) that landed at Portela Airport, Lisbon, on 15 January 1943 due to a navigation error during a USAAF ferry flight from the UK to North Africa.
Purchase
Portugal acquired this and other Airacobras for $20,000 each, forming the basis of its Airacobra fleet.
Formation of Esquadrilha Airacobra
Unit Name
The aircraft were grouped into Esquadrilha Airacobra (Airacobra Squadron), later renamed Esquadrilha 4 (Squadron No. 4).
Branch
Operated under the Aeronáutica Militar (Army Military Aviation), Portugal’s pre-1952 air force structure.
Operational Role
Primary Use
Training, air defence, and familiarization with modern fighter technology.
Combat Use
None—Portugal remained neutral, and the aircraft were not deployed in combat.
Fleet Size
Exact numbers are unclear, but several P-39s and P-400s were operated, mostly acquired through internment or postwar surplus.
Legacy and Retirement
Postwar Use
Continued in service into the late 1940s, helping modernize Portugal’s fighter capabilities.
Strategic Significance
Portugal’s Airacobras never saw combat, but they played a key role in transitioning the country’s air force from prewar biplanes to modern monoplane fighters.
The formation of Esquadrilha Airacobra marked Portugal’s first operational use of tricycle-gear, mid-engine fighters—an important step in pilot training and tactical evolution.
The Royal Air Force
Initial Order and Delivery
In September 1940, the RAF ordered 386 P-39D Airacobras, later increasing the order to 675 aircraft.
The first aircraft arrived at No. 601 Squadron RAF on 6 August 1941.
Operational Deployment
The RAF deployed the Airacobra for low-level missions, but quickly found its performance lacking—especially at high altitude due to the absence of a turbo-supercharger, which had been removed from the production models.
British pilots criticized its poor climb rate, limited range, and inadequate high-altitude capabilities.
Combat Use
The only recorded operational mission occurred on 9 October 1941, when four P-39s from No. 601 Squadron attacked German barges near Dunkerque, France.
This mission marked the end of RAF combat use of the Airacobra.
Withdrawal and Transfer
By March 1942, No. 601 Squadron had re-equipped with Supermarine Spitfires.
Summary
The RAF’s operational history with the P-39 Airacobra was short-lived and largely unsuccessful. The aircraft’s design—optimized for low-altitude combat—did not meet the RAF’s needs for high-altitude interception over Western Europe.
The Royal Navy
Origins and Transfer
Ordered by RAF
AH574 was part of the RAF’s initial Airacobra I batch (serials AH570–AH739), intended for No. 601 Squadron.
Rejected by RAF
Due to poor performance at altitude and operational limitations, the RAF rejected the type for frontline use.
Transferred to Royal Navy
AH574 was reassigned for test and experimental duties, becoming the only Airacobra operated by the Royal Navy.
Test Work and Carrier Landing
Assigned to HMS Pretoria Castle
AH574 was used for trials related to carrier operations and rubber deck landings.
Historic Landing
On 4 April 1945, legendary test pilot Captain Eric “Winkle” Brown made aviation history by landing AH574 on the flight deck of HMS Pretoria Castle—the first-ever carrier landing by an aircraft with retractable tricycle landing gear.
The landing was unofficial and staged under the guise of an “emergency” to test feasibility.
Brown had pre-arranged with Captain Caspar John to simulate engine trouble on final approach.
The aircraft caught the arrestor wire successfully, but its long takeoff run nearly prevented it from leaving the deck again.
Final Years and Scrapping
Postwar Use
AH574 continued to serve as a personal transport and test aircraft for Brown.
Final Flight
In March 1946, a Bell test pilot flew AH574 and declared it dangerously decayed.
Scrapped
Brown performed a farewell aerobatic flight on 28 March 1946 before the aircraft was scrapped.
He was later gifted a Fieseler Storch as a replacement.
Legacy
AH574’s brief but colorful career stands out for its pioneering carrier landing and association with one of Britain’s most celebrated test pilots.
Though never a combat aircraft in Royal Navy service, it earned a unique place in naval aviation history.
The Royal Australian Air Force
Total Received
22 aircraft were officially taken on RAAF charge, with serial prefix A53-.
Sources
These were mostly ex-USAAF aircraft, including P-39D, P-39F, and P-400 variants.
Squadrons Involved
Nos. 23, 24, 82, and 83 Squadrons RAAF were issued Airacobras, though often only on paper or for limited use.
Role and Usage
Primary Role
The Airacobras were used primarily for training, familiarization, and local defense duties.
Combat Use
There is no record of RAAF Airacobras engaging in combat operations.
Most combat missions in the region were flown by USAAF units.
Maintenance and Ferrying
Several aircraft were damaged or lost during ferry flights and training, highlighting operational challenges.
Transfers and Withdrawals
Shared Use
Some aircraft were temporarily assigned to the RAAF before being returned to the USAAF.
Example
P-39D-BE 41-6968 “R” of the 35th Pursuit Squadron was allocated to the RAAF as A53-14 after repairs, used by multiple squadrons, and returned to the USAAF in September 1943.
Final Status
Most Airacobras were withdrawn from use by 1944, with some condemned due to damage or obsolescence.
Strategic Context
The RAAF was desperate for fighters in early 1942, and the Airacobra was a stopgap measure.
Its poor high-altitude performance and vulnerability to Japanese fighters like the A6M Zero limited its appeal.
The aircraft was far more successful in Soviet hands, where low-altitude combat was the norm.
Summary
The RAAF’s use of the P-39 Airacobra was minimal and mostly logistical.
While it filled a temporary gap in fighter availability, it never saw combat under Australian command.
Its legacy in RAAF service is overshadowed by more capable aircraft like the P-40 Kittyhawk and the Spitfire.
The Soviet Air Forces
Acquisition and Deployment
Over 4,700 P-39s were delivered to the USSR via Lend-Lease, making it the second-most supplied fighter after the P-40.
Variants
Primarily P-39D, P-39N, and P-39Q models.
Delivery Route
Most aircraft arrived via the Alaska–Siberia (ALSIB) route, flown by Soviet ferry pilots from Fairbanks to Krasnoyarsk.
Operational Role
Combat Environment
The Eastern Front’s low- to medium-altitude engagements suited the Airacobra’s strengths perfectly.
Roles
Air superiority
Ground attack
Close air support
Units
Deployed across multiple Guards Fighter Regiments, including elite formations like the 9th Guards Fighter Aviation Regiment.
Effectiveness
The P-39 scored more aerial victories in Soviet hands than any other American fighter type in any conflict.
Technical Adaptations
Armament
Soviet pilots valued the nose-mounted 37mm cannon for its destructive power against both aircraft and ground targets.
Modifications
Some aircraft were stripped of wing guns to improve manoeuvrability and reduce weight.
Legacy and Withdrawal
Postwar Use
Continued in service into the late 1940s before being replaced by Soviet-built jets like the MiG-9 and MiG-15.
Legacy
The P-39 became a symbol of Soviet-American cooperation and a cornerstone of Soviet air power during the war.
Strategic Impact
Unlike in Western Europe, where high-altitude performance was critical, the P-39 thrived in Soviet service due to its ruggedness, firepower, and suitability for low-altitude combat.
It was instrumental in securing air superiority and supporting ground offensives from Kursk to Berlin.
Soviet Naval Aviation
Acquisition and Allocation
Supplied via Lend-Lease, alongside thousands of P-39s delivered to the USSR.
Variants Used
Mostly P-39N and P-39Q models, identical to those used by the VVS.
Operational Role
Primary Missions
Coastal air defence
Escort for naval convoys and reconnaissance aircraft
Ground attack and interdiction near port facilities
Combat Use
Engaged German aircraft over the Baltic and Black Sea, including Ju 88 bombers and Bf 109 fighters.
Altitude Advantage
The P-39’s low-altitude performance was ideal for naval operations, which rarely required high-altitude interception.
Notable Units
Naval fighter regiments such as the 78th IAP-VVS VMF (Fighter Aviation Regiment of Naval Aviation) operated the type.
Withdrawal and Legacy
Postwar Use
Continued briefly after WWII before being replaced by Soviet-built aircraft like the Yak-9U and early jet fighters.
Legacy
Though overshadowed by VVS operations, the P-39 helped modernize Soviet Naval Aviation and provided a capable platform for defending key maritime zones.
Strategic Significance
The P-39’s service with Soviet Naval Aviation was a tactical complement to its broader success in the Red Army Air Force.
It offered reliable firepower and manoeuvrability for low-altitude missions over water and coastal terrain, contributing to the defence of Soviet maritime assets.
Operational History and Combat Performance
The Bell P-39 Airacobra saw widespread action across multiple theatres during World War II, including the South-west Pacific, Mediterranean, and Eastern Fronts.
However, its performance at high altitudes was compromised by the use of a single-stage, single-speed supercharger, limiting its effectiveness above 17,000 feet (5,200 meters).
In Western Europe and the Pacific, the aircraft was often outclassed by enemy interceptors and gradually transitioned away from air superiority roles.
Instead, the P-39 found its niche at lower altitudes, where it was frequently employed in ground-attack and strafing missions.
Variants
XP-39
Bell Model 11, one prototype 38–326 first flown 6 April 1938.
Powered by a 1,150 hp (860 kW) Allison V-1710-17 engine and was fitted with a General Electric B-5 turbo-supercharger, creating a two stage supercharging system similar to the P-38
(engine-mounted mechanical supercharger, remote exhaust-driven turbo-supercharger as a second stage for high-altitude)
Aircraft remained unarmed.
Later converted to XP-39B.
XP-39B
One conversion first flown 25 November 1939.
Streamlined XP-39 based on NACA wind tunnel testing resulting in revised canopy and wheel door shape, oil cooler/ engine coolant radiator intakes moved from right fuselage to wing roots, fuselage increased length by 13 in (330 mm) and decreased wingspan (by 22 in (560 mm).
The turbo-supercharger was removed, and the single-stage, single speed, supercharged 1,090 hp (810 kW) Allison V-1710-37 engine remained.
The carburettor air intake was moved behind the canopy.
YP-39
Bell Model 12, service test version, 1,090 hp (810 kW) V-1710-37 engine.
Armed with an M4 37 mm cannon with 15 rounds, 2 × .50 calibre machine guns with 200 rpg, and 2 × .30 calibre machine guns with 500 rpg in the nose.
Wider vertical tail than XP-39B.
13 completed with the first flying on 13 September 1940.
YP-39A
One intended to have a V-1710-31 engine, but was delivered as a regular YP-39.
P-39C
Bell Model 13, initial US Army designation P-45 Airacobra.
First flown in January 1941, it was the first production version, identical to YP-39 except for 1,150 hp (860 kW) V-1710-35 engine.
Armed with 1 × 37 mm cannon, 2 × .50 calibre and 2 × .30 calibre machine guns in the nose.
Aircraft lacked armour and self-sealing fuel tanks.
Twenty were produced out of an order of 80, with the remainder completed as P-39Ds.
P-39D
Bell Model 15, production variant based on the P-39C with additional armour and self-sealing fuel tanks.
Armament increased to 1 × 37 mm cannon with 30 rounds, 2 × .50 calibre and 4 × wing mounted .30 calibre machine guns; 429 produced.
P-39D-1
Bell Model 14A, production variant fitted with a 20 mm M1 cannon instead of 37 mm cannon.
Specifically ordered for delivery under Lend-Lease.
336 produced.
P-39D-2
Bell Model 14A-1, production variant again intended for lend lease and fitted with 20 mm cannon, but with 1,325 hp (988 kW) V-1710-63 engine.
158 produced.
P-39D-3
26 conversions from P-39D-1 to photo reconnaissance configuration; K-24 and K-25 camera in rear fuselage, extra armour for oil coolers.
P-39D-4
11 conversions from P-39D-2 to photo reconnaissance configuration.
Same modifications as D-3 aircraft.
XP-39E
Bell Model 23.
three P-39Ds modified for ground and flight testing first flown 21 February 1942.
Intended for 2,100 hp (1,600 kW) Continental I-1430-1 engine but only flown with 1325 hp Allison V-1710-47 engine.
Used to test various wing and vertical tails.
Fuselage lengthened by 21 in (530 mm) and used in the development of the P-63.
The production variant, with the Continental engines was to be designated P-76; there was no Bell XP-76 as such.
P-39F
Bell Model 15B, production variant with three-bladed Aeroproducts constant speed propeller.
229 built.
P-39F-2
27 conversions from P-39F for ground attack and tactical reconnaissance.
P-39G
Bell Model 26, 1800 ordered, intended to be a P-39D-2 with a different propeller.
Later cancelled, with aircraft delivered as P-39K, L, M and N.
P-39J
Bell Model 15B, P-39F with 1,100 hp (820 kW) V-1710-59 engine with automatic boost control; 25 built.
P-39K P-39K-1
Bell Model 26A.
Fitted with an Aeroproducts propeller and powered by a 1,325 hp (988 kW) V-1710-63 engine.
210 built.
P-39K-2
Six conversion from P-39K-1 for ground attack and reconnaissance.
P-39K-5
One conversion with a V-1710-85 engine to serve as a P-39N prototype.
P-39L
P-39L-1
Bell Model 26B, similar to P-39K with Curtiss Electric propeller and higher gross weight.
250 built.
P-39L-2
Eleven conversions from P-39L-1 for ground attack and reconnaissance.
P-39M
P-39M-1
Bell Model 26D, variant with an 11 ft 1 in (3.38 m) Aeroproducts propeller, 1,200 hp (890 kW) V-1710-83 engine with improved high-altitude performance, 10 mph (16 km/h) faster than P-39L at 15,000 ft (4,600 m).
240 built.
P-39M-2
Modification of P-39M-1 for ground attack
P-39N
Bell Model 26N, originally part of the P-39G order.
1325 hp V-1710-85 engine.
10 ft 4 in (3.15 m) Aeroproducts propeller and different reduction gear ratio.
Starting with the 167th aircraft, the propeller diameter was increased to 11 ft 7 in (3.53 m) and internal fuel reduced from 120 to 87 US gal (450 to 330 L; 100 to 72 imp gal); 500 built.
P-39N-1
Variant with internal changes to adjust centre of gravity when nose guns were fired; 900 built.
P-39N-2
128 P-39N-1 converted with additional belly armour and cameras in rear fuselage.
P-39N-3B
35 P-39N converted with additional belly armour and cameras in rear fuselage.
P-39N-5
Variant with armour reduced from 231 to 193 lb (105 to 88 kg)
Armour plate replaced the bullet-proof glass behind the pilot
SCR-695 radio was fitted, and a new oxygen system was installed; 695 built.
P-39N-6
84 P-39N-5 converted with additional belly armour and cameras in rear fuselage.
P-39Q
The final production variant last one built in August 1944.
P-39Q-1
Bell Model 26E, variant with wing-mounted .30 calibre machine guns replaced with a .50 calibre with 300 rounds of ammunition in a pod under each wing.
Armour was increased to 231 lb (105 kg); 150 built.
P-39Q-2
Five P-39Q-1s modified to carry cameras for photographic reconnaissance by adding K-24 and K-25 cameras in the aft fuselage.
P-39Q-5
Production variant with reduced armour (193 lb (88 kg)), fuel capacity increased (110 US gal (420 L; 92 imp gal)).
Type A-1 bomb-sight adapters added; 950 built.
TP-39Q-5
One conversion to a two-seat training variant with additional cockpit added in nose – no armament.
Enlarged tail fillet and a shallow ventral fin added.
P-39Q-6
148 P-39Q-5s modified to carry cameras for photographic reconnaissance by adding K-24 and K-25 cameras in the aft fuselage.
P-39Q-10
Variant with increased armour (228 lb (103 kg)), fuel capacity increased (120 US gal (450 L; 100 imp gal)).
Automatic Boost controls added and throttle and RPM controls coordinated.
Winterisation of oil systems and rubber mounts added to the engines; 705 built.
P-39Q-11
Eight P-39Q-10s modified to carry cameras for photographic reconnaissance by adding K-24 and K-25 cameras in the aft fuselage.
P-39Q-15
Production variant with reinforced inclined deck to prevent .50 calibre machine gun mounting cracking, bulkhead reinforcements to prevent rudder pedal wall cracking, a reinforced reduction gearbox bulkhead to prevent cowling former cracking, and repositioning of the battery solenoid.
Oxygen system reduced from four bottle to two; 1,000 built.
P-39Q-20
Production variant with minor equipment changes.
The under-wing .50 calibre machine gun pods sometimes omitted; 1,000 built.
P-39Q-21
109 P-39Q-20 fitted with a four-bladed Aeroproducts propeller.
RP-39Q-22
12 P-39Q-20s converted to two-seat trainers.
P-39Q-25
Production variant similar to the P-39Q-21 but with a reinforced aft-fuselage and horizontal stabiliser structure; 700 built.
P-39Q-30
Production variant that reverted to the three-bladed propeller; 400 built.
ZF-39
Remaining examples in service, re-designated in June 1948.
P-45
The P-45 was the initial designation of the P-39C or Model 13.
XFL-1 Airabonita
One prototype tail-wheel undercarriage carrier fighter for the USN.
XTDL-1
United States Navy (USN) designation for two P-39Qs used as target drones.
Assigned to NAS Cape May for test work.
Later redesignated F2L-1K.
F2L-1K
XTDL-1 drones re-designated.
P-400
An export model of the P-39 with a less powerful cannon, using a 20 mm Hispano cannon rather than the standard 37 mm cannon.
It also had 2 .50 calibre machine guns in the nose, and 2 x .30 calibre machine guns in each wing.
Airacobra I
Bell Model 13, Royal Air Force (RAF) designation for three P-39Cs delivered to the A&AEE Boscombe Down for testing.
Airacobra IA
Bell Model 14.
Briefly named Caribou.
1,150 hp V-1710-E4 engine, 1 × 20 mm cannon with 60 rounds and 2 × .50 calibre machine guns mounted in the nose and four .303 calibre machine guns were mounted in the wings.
IFF set removed from behind pilot.
*Notice*
The designation IA indicates direct purchase aircraft (as opposed to Lend-Lease); 675 built.
The USAAF operated 128 former RAF aircraft with the designation P-400.
