The Bell P-39 Airacobra is yet another in the long line aircraft studies stemming from World War 2 in the "what-might-have been" category. The system had all the looks of a top performer, armament that could go head-to-head with any contemporary and a design philosophy that could have brought about a whole new era is aircraft engineering. Unfortunately for the aircraft, several key requirements effectively doomed the Airacobra as a subjective failure - never quite living up to expectations. Still, the system served well enough, save for its intended role of high performance fighter, and went on to become a steady performer in the low-level attack role (excelling in combat under 10,000 feet). She was sent en masse to the Soviets via Lend-Lease and shunned by the British altogether - the latter finding that the aircraft (as advertised) possessed none of the capabilities being marketed by the Bell prototype.
Generally a very pleasing aircraft to look at, the P-39 design came about at a time when streamlining aircraft shapes were just coming into their own. The P-39 was a vast departure from most aircraft being conceived of at the time and featured several design elements that distinguished the type from her contemporaries. Chief among these was in the internal layout, the Allison series engine mounted in the middle of the fuselage just aft of the cockpit. Engineers ran an extended shaft from the engine through a center bearing underneath the pilots feet to the front fuselage section where the three-blade propeller and reduction gear were mounted. As a result of this engine placement, the engine had to be fed through intakes mounted along the fuselage as opposed to a conventional placement in the nose. In early P-39 forms, this meant intakes were added to the sides of the fuselage just aft of the cockpit. Other forms mounted these intakes along the wing roots and the most identifiable form saw the intake affixed to the top of the fuselage. Wings were low-mounted monoplane assemblies and the empennage featured a traditional "T-style" arrangement with a single vertical fin. The P-39 also featured a powered tricycle landing gear system, a relatively new concept in the art of aircraft design for the time.
In what turned out to be effectively an early form of the "bubble" canopy, the Airacobra featured a complex canopy design which offered up unparalleled vision over the entire design. The pilot sat in a very ergonomically-minded cockpit that featured two automotive-style "swing" doors to either side of his seat. The windows in these doors were fully retractable and done so through a car-like crank handle. Upon having to exit his aircraft in the event of damage or power loss, the pilot simply jettisoned the doors via lever and rolled out one side or the other, eventually slipping off the edges of the respective wing. If enough time was allotted, he could even make his way to the wings edge and make a controlled jump.
France initially ordered the P-39 early in the war but was forced to delay delivery of these units due to the country's capitulation to the German invasion. However, they would be one of the last operators of the machine by war's end and for a time afterwards. The P-39 would also be fielded in limited quantities by Allied Italian forces for a time but did little to show for their Airacobra use. Portugal interned some eighteen wayward P-39s that landed on their soil, ultimately applying payment to the United States for these captured systems at the end of the war. Regardless, the nation was glad to add some modern fighters to its stable. The Royal Australian Air Force received a mix of D- and F-models pending the Japanese invasion of the Australian mainland. These were returned to the United States when the threat officially subsided.
Not to say that the P-39 was a completely useless dogfighting platform - it should be noted that the aircraft could provide a fair fight in the hands of a skilled pilot knowing the limitations of his system. If the Airacobra could drag an opponent down below 10,000 feet, it stood a definitive chance to overtake an enemy through ingenuity and firepower (controlled friendly war games with even the fabled Vought F4U Corsairs showed this to be true). Performance-wise, however, the P-39 was devoid of any truly exceptional qualities when compared to the fighter types that were purpose-built for the role including the heavy Republic P-47 Thunderbolts.
However, the P-39 made many-an ace for the Soviet Air Force where air-to-air battles along the East Front typically unfolded under the optimal 10,000 feet ceiling limit of the Airacobra. Aleksandr Ivanovich Pokryshkin, the third highest scoring Allied ace, earned 60 Luftwaffe victims flying in his P-39. Similarly, Grigori Rechkalov - the second top scoring Soviet ace - earned 44 such victories piloting a P-39. Initial P-39 deliveries to the Soviet Union arrived with the British-selected 20mm Hispano-Suiza nose cannon while later models came with the more potent American-endorsed M4 37mm cannon - the latter adjustment making quite a difference. It is of note here that the United States did not deliver the M80 AP round for these autocannons through Lend-Lease. In their place came 1.2 million rounds of M54 HE rounds, proving useful for air and soft ground targets. As such, the Soviet P-39s were not used in the dedicated "tank-busting" role.
The USAAF fielded the P-39s in limited force across European operations. The 31st Fighter Group was set up and comprised of the 307th, 308th and 309th Fighter Squadrons. These men and their mounts arrived in England in July of 1942. Seeing prompt action, the Airacobra proved no match for the Luftwaffe. In one such fighter sweep, six of the twelve P-39s were lost to enemy action. It was not long after that the USAAF pulled the Airacobra form the theater, replacing the 31st Fighter Group P-39s with tried-and-true Supermarine Spitfires. Still, P-39s saw combat actions in support of the Operation Torch landings over North Africa and then over Italy. These primarily flew under the 10,000-foot ceiling limit, used in the close-support role and escorted by fighters. No German column, troop concentration or supply depots were safe.
The P-39 was set into service in the Panama Canal zone under fear that the area was ripe for an attack from either ocean from Japanese or German submarine groups.
After the surprise attack on Pearl Harbor (December 7th, 1941) the P-39 was pushed into the Pacific Theater of War and saw its first recorded combat with the 8th Pursuit Group. This occurred with the crews being short of spare parts and even shorter mechanical know-how. Following the initial P-39C and P-39D models were the P-39F and P-39G model series sporting an Aeroproducts-brand propeller system. Several more variations ensued for the type but most revolved around differing engines. P-39s (and her crews for that matter) were subjected to the harsh tropical environment that was the Pacific region
The Airacobra aircrews and ground crews surely showed their mettle in multiple combat actions basically doing much with a relatively limited set. It became evermore apparent that the P-39 in the Pacific Theater would soon need to be addressed and was - for the most part - properly done so with the addition of the Lockheed P-38 Lightnings delivered en masse to the region. Over the vast open spaces of the Pacific, the little P-39 was soon found to lack the needed range of a protracted island-hopping conflict so its replacement was warranted. The environment proved a nightmare for maintenance and reliability of the mechanical components as well. The Airacobra crews fought on, however, with their beautiful little ugly machines and played a key role in the protection of Australia from Japanese invasion, defending Port Moresby with a certain level of ferocity.
Japan mounted an invasion across the Aleutian island chain off of Alaska in an effort to setup submarine replenishment points for actions in the Northeast Pacific. P-39s were thrown into the fray and mounted a valiant and pivotal defense against imposing odds. The weather in the region played poorly on the hapless American pilots, forced to wear layers of clothing and contend with the P-39s ill-suited cabin heaters. Mechanical issues were plenty and poor weather resulted in many accidents. When opportunity presented itself, however, these airmen and their P-39 mounts rained hell on the Japanese that were attempting to establish a foothold on the island chain. Targets of opportunity became flying boats, shipping vessels, airfields and depots. In all, 20 enemy aircraft were destroyed for the loss of just one P-39.
In the end, the P-39 was very much of what was not intended for the design. It lacked true fighter performance thanks to the US Army decision to take out the turbosupercharger and fit in a lower-rated Allison. The aircraft was specifically and primarily constructed for the role of a high-performance fighter but much of this was lost when the system was relegated to the close-air support role. The primary 37mm armament was the systems true saving grace as the down-graded wing machine guns did not match well against contemporary aircraft mounting multiple heavy caliber systems with a combination of cannon.
And a fighter design intended to be the American answer, she essentially became nothing more than a temporary solution for air forces around the globe. The landing gear issues and general mechanical reliability did not endear the system to most though the aircraft was still well-regarded for those pilots that saw beyond her deficiencies. In the end, the Airacobra was a snake that truly lacked a poisonous bite in her intended role but seemed to make for it in other ways - internally and externally. In any case, the P-39 is regarded as a modest success in most circles but only her pilots know her true value.
Some 9,584 P-39 examples were produced during her tenure at the cost of $50,666 dollars per unit in 1944 money. Production ran from 1940 to May of 1944. Formal introduction of the series began in 1941.
- Ground Attack
- Close-Air Support (CAS)
30.15 ft (9.19 m)
33.99 ft (10.36 m)
11.84 ft (3.61 m)
5,611 lb (2,545 kg)
8,400 lb (3,810 kg)
386 mph (621 kph; 335 kts)
35,991 feet (10,970 m; 6.82 miles)
650 miles (1,046 km; 565 nm)
3,333 ft/min (1,016 m/min)
1 x 37mm Oldsmobile cannon firing through the propeller hub with 34 rounds OR 1 x 20mm Hispano-Suiza cannon.
2 x 12.7mm machine guns in the upper forward fuselage with 200 rounds each.
4 x 7.62mm machine guns in wings (2 to a wing) with 1,000 rounds each.
1 x 500 lb bomb externally mounted at fuselage centerline.
P-39 - Base Series Designation
XP-39 - Prototype Model Designation sans armament.
YP-39 - Prototype Preproduction Models of which 13 were produced; improved XP-39 model.
YP-39A - Preproduction XP-39 Model fitted with an Allison V-1710 engine sans turbocharger; single high-altitude test frame conversion model.
YP-39B - Based on the XP-39; fitted with new engine sans turbocharger; single unit produced.
P-45 - Initial Production Designation offered by the US Army to signify major changes to model P-39C; later dropped in favor of P-39 designation.
P-39C - Initial Production Models; 80 examples produced; 60 P-39C models became P-39D types.
P-39D - Production Model fitted with self-sealing fuel tanks and increased heavier armament (addition of 2 x 12.7mm machine guns in upper forward fuselage); Allison V-1710-35 water-cooled engine generating 1,150hp; conversion models from P-39C series.
P-39D-1 - Lend-Lease Model with Hispano-brand 20mm cannon; improved P-39D models with self-sealing fuel tanks; 863 examples produced.
P-39D-2 - Lend-Lease Model with Allison V-1710-63 (E6) powerplant; improved P-39D-1 model series; 158 on order; 1 conversion model from P-139D-1.
XP-39E - 3 examples produced with new powerplant of Continental I-1430-1 at 2,100hp; becoming the XP-63 "Kingcobra" prototype.
P-39E - Improved P-39D-1 model; though 4,000 were on order none of this type were produced.
P-39F-1 - Based on the P-39D model but fitted with Aeroproducts-produced constant-speed propeller system.
P-39F-2 - P-39F models modified for photo reconnaissance duties; 2 converted as such.
P-39G - 1,800 were ordered though eventually becoming the K, L, M and N models in the series.
P-39H - Designation Not Used
P-39J - Modified P-39D-1 model series with new engine and auto boost feature; 25 examples produced.
P-39K - Fitted with V-1710-63 powerplant and Curtiss-produced propeller system; based on P-39F model series; 210 examples produced.
P-39L - Modified P-39K series with Curtiss brand propellerand rocket rails installation; 250 examples produced.
P-39M - Fitted with V-1710-83 powerplant capable of 1,200hp and a larger propeller system; gearing changed; 240 examples produced.
P-39N - Improved P-39M series; fitted with V-1710-85 powerplant; decreased armor protection and fuel for increased weight and performance.
P-39P - Designation Not Used
P-39Q - Improved P-39N series; 1 x 37mm cannon and 4 x 12.7mm machine guns - two held in underwing gunpods and synchronized to fire through the propeller.
Bell Model 14 - French Order Model Designation; never delivered.
Airacobra Mk I - British Delivery Models
P-400 Airacobra I - Royal Air Force Designation
TP-39F - Dual-Seat Trainer Model
RP-39Q - Limit Production Dual-Seat Trainer Model
F2L - US Navy Target Drone Designation
XFL-1 "Airabonita" - Single Example Prototype Model for evaluation by US Navy; traditional landing gear array instead of tricycle type.
A-7 - Proposed Radio-Controlled Drone
TDL - US Navy Radio-Controlled Target Drone