Bell P-39J Airacobra - The Rare-Acobra

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Bell P-39J Airacobra

   Hello everybody. I’d like to introduce and suggest the Bell P-39J Airacobra for the US aviation tech tree, and this is one of my series of suggestions for the early P-39 variants in the US Army Air Corps and US Army Air Force services. This P-39J was a direct development of the P-39F-1 and P-39D based on the Model 15 with a different engine and minor changes.


TL;DR:

A P-39 variant (Model 15B) akin to the P-39F-1 but with a 1,100 hp Allison V-1710-59 engine and an automatic boost control.


History

Production of P-39Fs totaled 229 aircraft in an order of 244 in September 1940. The remaining 25 were made as the P-39Js that would have been the final P-39Fs in the same year. They were delivered with an improved 1,100 hp V-1710-59 engine and automatic manifold pressure regulator, in other words, automatic boost control. Externally identical to the P-39F-1, the P-39Js had twelve exhaust stubs on each side and used the Aerproducts constant-speed propeller. Company Model 15B was designated to the P-39J.

Sources mentioned the P-39Js, along with P-39Fs, were sent to Africa. Some P-39Js remained at the training air bases on the mainland, and some were deployed to replace the older Airacobra in the Aleutians and southwest Pacific. Sadly, at this point, there are no sources that have added more specific details of the P-39Js in service beyond the one in the Aleutians.

The sources found that a P-39J of the 57th Fighter Squadron of the 54th Fighter Group was assigned with tour duty in Kodiak, Alaska, from June through December 1942. This P-39J was identified with serial number 41-7073 and operated by a pilot, Lt. Leslie Spoonts.

The 57th Fighter Squadron was sent on emergency temporary duty to the Aleutians during the Japanese invasion in June 1942, occupying the islands of Attu and Kiska and lasting until August 1943. This marked the only military campaign of World War II fought on North American soil.

Lt. Spoonts flew from Kodiak Island, Alaska, during the Aleutians campaign. During Lt. Spoonts’ tour duty, he claimed to have downed three Japanese aircraft, and the three victory symbols were painted below the cockpit of his P-39J. As interesting as his claim was, unfortunately, there are no official records to verify and confirm his claims. It was speculated he made the claims after strafing attacks on float planes found in the waters surrounding the Japanese-held islands.

The P-39J’s unit was stationed on Kodiak Island from mid-1942 until it returned to Bartow Field, Florida, in early 1943.

No existing P-39Js have survived as museum aircraft, as it appeared they were scrapped after the war. A P-39Q-20 with serial number 44-3908 is on display in the US Air Force Museum in Dayton, Ohio, and painted in the markings of Spoonts’ P-39J.


Specifications

Bell P-39J Airacobra

General Characteristics

  • Crew: 1 (Pilot)
  • Length: 30 ft 2 in (9.19 m)
  • Height: 11 ft 10 in (3.6 m)
  • Span: 34 ft (10.36 m)
  • Wing Area: 213.22 sq ft (19.81 sq m)
  • Propeller Type: 3-bladed Aeroproducts Hydraulic propeller
  • Powerplant: Allison V-1710-59 liquid-cooled piston engine with single-stage, single-speed supercharger
    → 1,100 hp (809 kW) @ 3,000 rpm @ sea level - 13,800 ft (4,206 m)
  • Internal Fuel: 120 US gal. (454 L)
  • Oil Tankage: 13.8 US gal. (52.2 L)
  • Empty Weight: ~6,300 lb
  • Gross Weight: ~7,830 lb
  • Max. Takeoff Weight: ~8,260 lb

Performance*

  • Power-to-Weight Ratio: ~0.14 (0.23 kW/kg)
  • Critical Altitude Speed: 360 mph (579 km/h)
  • Wing Loading: ~36.7 lb/sq ft (179.2 kg/sq m)
  • Rate of Climb: ~2,500 fpm (12.7 m/s)
  • Time to Altitude: ~5.7 minutes to 15,000 ft (4,572 m)
  • Service Ceiling: ~32,100 ft (9,784 m)
  • Combat Range: ~800 miles (1,288 km)
  • Max. Range: ~1,545 miles (2,486 km) w/ external ferrying tanks

“*” Unfortunately, I can not find any existing technical manuals for the P-39J. I have re-used the P-39 data from the Pilot’s Flight Operating Instructions manual for P-39Q-1 to make rough estimates for the P-39J.

Armament

  • Guns:
    • 37-mm M4 cannon (30 rounds)
    • 2 x .50-cal. M2 Browning machine guns (200 - 270 rpg; 400 - 540 rounds)
    • 4 x .30-cal. M1919 Browning machine guns (250 - 1,000 rpg; 1,000 - 4,000 rounds)
  • Bomb:
    • 1 x 250-lb M57 bomb
    • 1 x 300-lb M31 bomb
    • 1 x 500-lb M43 bomb
    • 1 x 600-lb M32 bomb
  • Drop Tank:
    • 1 x 75-gal drop tank
    • 1 x 175-gal drop tank

Images


Conclusion | Why it should be in the game

   I made this suggestion to request more World War II-era vehicles for War Thunder. I feel the P-39J could be a good candidate to add as a premium aircraft, considering the J model was a rare aircraft with limited service in the US Army Air Forces. Performance-wise, I believe the P-39J is similar to the P-39D. It should be climbing and maintaining altitude better and more efficiently with the automatic boost control. Thus, the P-39J would make a welcoming addition to the P-39 Airacobra family for US aviation, providing an opportunity for dedicated completionists.


See Also - P-39 Family

   I made additional suggestions for other P-39 variants. If you’re interested in these suggestions, check them out!


Sources


Thank you for taking the time to read my suggestion! 😃

1 Like

You could’ve called it the “Rare-acobra” lol

Also can’t you use the few numbers from the Q-1 manual’s list of variants

Done - thank you, that’s a brilliant idea 😃

Yes, I did take the figures of top speed and weights from that Q-1 manual for this P-39J. As for the top speed, I am unsure whether it was at sea level or around 10,000 - 15,000 feet. I’ll try and look for the engine ratings somewhere on Internet or archived records.

A +1 from me, always down for more early variants

1 Like