Bell XFL-1 Airabonita - US Navy’s “Airacobra”

Would you like to see this in-game?
  • Yes
  • No
0 voters

Bell XFL-1 Airabonita

   Hello everybody. I’d like to introduce and suggest the Bell XFL-1 Airabonita as a potential addition to US aviation in War Thunder. The XFL-1 was a carrier-based interceptor developed by Bell for the United States Navy, created in parallel with the land-based XP-39 Airacobra for the Army. Only one prototype was built and completed in the spring of 1940. Although an ambitious project for Bell, the Airabonita encountered early design issues and ultimately did not advance to production, losing out to the Chance Vought XF4U-1 Corsair.


Key Characteristics

  • Carrier-based interceptor aircraft with tail-wheel undercarriage
  • Resembled its land-based counterpart, the P-39 Airacobra
  • Planned armament: 2 x 0.30-cal and 1 x 0.50-cal machine guns
  • Powered by an Allison inline piston engine
  • Equipped with small anti-aircraft bombs mounted in both wings

History

The Bell XFL-1 Airabonita was an experimental carrier-based interceptor developed by Bell for the U.S. Navy, aiming to replace outdated biplane fighters still in service. Designed in response to a Navy specification issued on January 1, 1938, the XFL-1 was envisioned as a lightweight, high-performance fighter.

Bell submitted its design proposal alongside Brewster, Curtiss, Grumman, and Vought-Sikorsky on April 11, 1938. After review, the Navy awarded prototype contracts to Bell, Grumman, and Vought-Sikorsky for testing and evaluation. Bell received a contract on November 8, 1938, to proceed with the carrier-based XFL-1 Airabonita, also developed in parallel with the land-based XP-39 Airacobra for the Army. The XFL-1 was powered by a 1,150-hp Allison V-1710-6 inline engine driving a Curtiss Electric three-blade propeller, though it lacked a high-altitude supercharger.

One key difference between the XFL-1 and the XP-39 was the undercarriage configuration: the XFL-1 used a conventional tailwheel landing gear instead of the XP-39’s tricycle gear, making it better suited for carrier operations. The XFL-1 also featured a larger wingspan, shorter fuselage, and a smaller rudder. The pilot’s seat was raised, which required a modified canopy design for visibility, and a small window was added below the nose to aid in carrier landings. The airframe was strengthened to withstand the stresses of carrier operations, and an arresting hook was installed. Additionally, the air inlets originally located in the wing roots were later replaced with under-fuselage scoops due to repositioned main landing gear struts to correct the shifted center of gravity.

The XFL-1’s armament included two .30-cal machine guns and one .50-cal machine gun. The mockup was inspected on December 20, 1938, but development was slowed by issues with the center of gravity, pushing back its expected first flight to the fall of 1939.

By April 1940, Bell completed the XFL-1 prototype, which underwent its maiden flight on May 13. However, this flight was accidental, as the aircraft was performing a high-speed taxi test when a gust lifted it off the runway. The test pilot managed a safe landing despite the unexpected takeoff and the flotation bags in the wings inflating mid-flight. The second flight attempt on May 20 ended abruptly when the engine failed shortly after takeoff, forcing an emergency landing in a nearby ditch.

Flight testing exposed significant challenges, including yaw oscillations, poor handling, and inadequate cooling. During a flight on June 29, the XFL-1 entered a spin due to yaw issues, but the pilot recovered when a Plexiglas canopy panel broke off, unexpectedly altering airflow over the rudder. These and other issues led to multiple modifications.

In July 1940, the Navy began official evaluation, but the XFL-1 struggled with carrier suitability, mainly due to its problematic landing gear. Additionally, the Allison engine, with its single-speed supercharger, provided inferior altitude performance compared to Navy fighters like the Grumman F4F Wildcat. The Navy sent the prototype back to Bell in December 1940 for further modifications, and it was returned to Naval Air Station Anacostia in February 1941 for continued testing.

Although the modifications improved stability and control, they added considerable weight, increasing the XFL-1’s empty weight by 8% and reducing its top speed from a promised 339 mph to 333 mph. Worse, the minimum airspeed rose to 78.6 mph, exceeding the Navy’s 70-mph limit for safe carrier landings, disqualifying it from carrier use.

Ultimately, the Navy canceled the XFL-1 program. The Chance Vought XF4U-1 Corsair, which achieved 400 mph in testing, proved a more promising option for carrier operations. The XFL-1’s limited armament and performance shortcomings made it uncompetitive, and in 1942, the prototype was used for destructive armament testing. The remains were ultimately last seen at Naval Air Station Patuxent River, marking the end of Bell’s attempt to produce a carrier-based interceptor for the Navy.


Specifications

Bell XFL-1 Airabonita

General Characteristics

  • Crew: 1 (Pilot)
  • Length: 29 ft 9 in (9.07 m)
  • Height: 12 ft 9.5 in (3.9 m)
  • Span: 35 ft (10.67 m)
  • Wing Area: 232 sq ft (21.6 sq m)
  • Propeller Type: Curtiss Electric three-blade propeller
  • Propeller Diameter: 10 ft 4.8 in (3.17 m)
  • Powerplant: Allison V-1710-6 piston inline engine
    → 1,150 hp (860 kW)
  • Internal Fuel: 200 US gal. (757 L)
  • Empty Weight: 5,161 lb (2,341 kg)
  • Gross Weight: 6,651 lb (3,017 kg)
  • Max. Takeoff Weight: 7,212 lb (3,271 kg)

Performance

  • Power-to-Weight Ratio: 0.17 hp/lb (280 W/kg)
  • Cruising Speed: 172 mph (277 km/h)
  • Sea Level Speed: 307 mph (494 km/h)
  • Critical Altitude Speed:
    • 336 mph @ 11,000 ft (541 km/h @ 3,353 m)
    • 333 mph @ 12,000 ft (536 km/h @ 3,658 m)
  • Stall Speed: 72 mph (116 km/h)
  • Wing Loading: 29 lb/sq ft (140 kg/sq m)
  • Rate of Climb: 2,630 fpm (13.4 m/s)
  • Time to Altitude: 3.8 minutes to 10,000 ft (3,048 m)
  • Service Ceiling: 30,900 ft (9,418m)
  • Combat Range: 965 miles (1,533 km)
  • Max. Range: 1,072 miles (1,725 km)

Armament

  • Guns:
    • 1 x 0.50-cal. M2 Browning machine gun (unknown # of rounds)
    • 2 x 0.30-cal. M1919 Browning machine guns (unknown # of rounds)
  • Bombs:
    • 20 x 5.2-lb (2.36-kg) anti-aircraft bombs

Artist’s impression of XFL-1 on an aircraft carrier during the carrier suitability trials.


Diagrams


Images


Conclusion | Why it should be in the game

   The XFL-1 Airabonita, while often described as a navalised version of the P-39, stands out as an intriguing possible addition for US aviation in War Thunder as a low-tier aircraft. Its most unique feature was its conventional tailwheel undercarriage and arresting gear, designed specifically for carrier operations that set it apart from the P-39. In gameplay terms, the XFL-1 wouldn’t offer a performance advantage over the P-400 or P-39 Airacobra due to its aerodynamic limitations despite being classified as a lightweight fighter. Its armament, featuring a single .50-cal M2 Browning rather than the more powerful 37-mm cannon, might be somewhat underwhelming but would still provide a unique experience for people who are fans of early naval aviation. In my view, it would be ideally suited as a low-tier event or premium aircraft.


Sources

  • P-39 Airacobra in Action (1980)
  • The American Fighter: The Definitive Guide to American Fighter Aircraft from 1917 to the Present (1987)
  • P-39 Airacobra in Detail & Scale Volume 63 (1999)
  • Bell P-39 Airacobra (The Crowood Press, 2000)
  • US Experimental & Prototype Aircraft Projects - Fighters: 1939-1945 (2008)
  • Bell XFL Airabonita - Wikipedia

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

3 Likes

I’ve been waiting for this suggestion! Take my absolute +1!

Also, here’s a photo of what was left of the XFL-1 prototype last time it was seen (it was near two buried Arado Ar 234s until relatively recently)

Spoiler

image

3 Likes

This is a sad photograph of the XFL-1 :( Btw, wow, I had no idea that the two Ar-234s were also buried alongside the XFL-1.

Aye! Sadly, they were buried under serval tons of concrete in the early 2000s after the relevant authorities deemed them to be of little historical value, citing that the National Air and Space Museum already had a 234 on display.

3 Likes

Bullshit. Also I like the XFL-1 seems cool

Agreed with both statements; someone surveyed the site again in 2013ish and found what they thought might have been one of the two Ar 234s. Supposedly, it was still in decent enough shape that it was identifiable as a 234, that said it would likely take a full scale survey to really see whats left

2 Likes

we must make a petition for what ever state they are in to find them fix them and put them in a museum NOW!!!

Sadly, they’re probably too far gone to restore; the best you could do is use the remains as templates to build new ones, and ditto with whatever is left of the XFL-1. But any of those undertakings would require a serious amount of funding and support from the US Navy, as NAS Patuxent River is still an active base.

Aside from the 234s, several other historically significant wrecks are also there. These include aircraft such as the XF8F-1 Bearcat, one of the XSN2J-1s, an FJ-1 Fury etc

+1, never knew this even existed. Armament might pose a challenge for some though, so this will be even lower BR than the regular P-39s.

When I saw the note of “no suspended weaponry”, it made me remember a distinct detail that I’d forgotten a long time ago about the XFL-1 having bomb bays. I couldn’t find any information on it and wondered if had just dreamed it or something until I found this twitter post, which contained this photograph:

Caption:
Bell Aircraft Corp.
Buffalo, N.Y.
XFL-1 bomb doors open showing bombs + boxes.
No. 5-150, 4-15-40

The twitter x post I found this on claims that these are anti-aircraft bombs for dropping on top of enemy bomber formations and the bottom viewing window pictured in the diagrams you posted is meant to facilitate aiming them.

So, normally I don’t think much of AI, but after finding nothing again on a couple searches, I decided to ask the generative search AI if the XFL-1 carried bombs and it found two more sources and then a booklet that corroborate this detail:

Key.Aero

“The XFL-1 featured five small bomb compartments with retractable doors in both wing lower surfaces, intended to contain two anti-aircraft bombs each. A transparent window was built into the lower fuselage, for the potential sighting of these archaic weapons.” - Malcolm V. Lowe

Bell FL Airabonita

“the USN also demanded that ten small bomb bays, five in each wing, be built into the underside of each wing to accommodate 5.2 pound (2.36 kilogram) bombs to be dropped over an enemy aircraft formation.” - Jack McKillop

Bell P-39 Airacobra, Bell P-63 Kingcobra

“Unusually, both wing lower surfaces included five small bomb compartments with retractable doors for up to ten aerial anti-aircraft bombs on each side. A transparent sighting window was built into the lower fuselage.” - FlyPast Spotlight

Additional

According to this reddit post the XF5F is supposed to have a similar setup, possibly using the same model of bomb.

Another project known for having a similar feature is Bell’s own YFM-1 Airacuda which could carry 20 x 30 lb bombs.

Unfortunately I haven’t been able to find any more information or photos discussing or showing off this feature of the XFL-1, but I figured this may be very interesting to note down! It might not be very useful in-game but I’m a strong proponent of vehicles having all of their unique or quirky features at their disposal.

Aloha,
-LF

4 Likes

Good job on finding that Info I want that even more you know how cool that would be to use in a dogfight >:)

2 Likes

Good find with that photograph. I knew the XFL-1 had anti-aircraft bombs, but I didn’t include them in the suggestion because I assumed they were too impractical.

Do you happen to know the explosive mass of each small AA bomb? My guess is it’s less than the 10-kg SD10C bombs carried by the He-51. Can these bombs detonate in the air, or do they require ground impact to trigger? I read somewhere that the XFL-1 would drop all 20 bombs simultaneously.

Thanks for sharing this information. I’ll update the XFL-1’s weaponry list to include this detail.

1 Like

Found more! I caught this drawing of a 5 lb. Anti-Aircraft Bomb Mark 34 on a reddit post about the XF5F

5 lb Anti-Aircraft Bomb Mark 34

That user didn’t know anything else about the bomb but said that he got it from this page about aircraft downward vision windows. I actually remember coming across this article a long time ago, but I haven’t found an image of the bomb on there. It does show the image of the XFL-1 bomb bays again

So it seemed to be mostly a dead end again, except I went back and looked up the Nose Fuze Mark 227 and got this:

Bomb Fuzes, Ordnance Pamphlet No.988

While it doesn’t mention much about the bomb it would be attached to, Chapter 4 of this pamphlet includes a detailed description of the Mark 227 fuze, its features and methods of operation:

Text version of page

1. Description:

(a) General — The Mark 227 (spinning fuze) is a nose fuze and is armed by centrifugal force caused by spin of the bomb after release. It is designed to detonate the Mark 34 Anti-Aircraft bomb on impact with materials, such as airplane wings, fuselage or light metal construction. About 1000 feet of altitude, corresponding to 1500 feet along the trajectory, is required for arming near sea level. Greater distance is required at high altitude because of the rarer atmosphere. It is safe for takeoffs or landings anywhere, including the decks of aircraft carriers. The weight of this fuze is 0.7 pounds. The principal parts of the fuze are the nose and the base, secured together by crimping the lower end of the nose over the base. A disc is interposed between the nose and the base. The nose contains the assembly of the firing pin dedents and firing pin. The base contains the assembly of the slider, slider detents, dowel pins, detonator and booster. The names of the various parts and the general arrangement drawings with the fuze in the unarmed and armed positions are shown in Figure 1-22. The Bureau of Ordnance General Arrangement Drawing is No. 236875. Figure 1-21 is a photograph of a completely assembled fuze.

(b) Bombs in which used — The Mark 227 fuze is used only in the Mark 34 Anti-Aircraft bomb which has a specially designed tail vane to cause the bomb to spin about its longitudinal axis when dropped.

(c) Arming — The fuze is in the unarmed position until the bomb in which it is carried is dropped from an airplane. Upon dropping, the bomb begins to rotate due to the angular setting of the bomb tail vanes. The fuze is armed by the centrifugal force set up by this rotation which moves a slider outward until stopped by the inner surface of the nose. At about 1500 r.p.m. the firing pin detents and slider detents are thrown outward thereby unlocking the firing pin and slider. The movement of the slider brings the detonator, located in the slider, into alignment with the firing pin and the booster lead-in. The fuze is then fully armed and will detonate on impact. Reliable arming of the fuze is dependent upon the free and easy movement of the sliding parts, and upon the nose being concentric with the axis of the fuze. To insure that all movable parts will function properly, they are assembled and tested by spinning, before acceptance.

(d) Explosive components — The explosive components consist of a detonator, booster lead-in and booster. The main booster charge consists of about 3.05 grams (0.107 oz.) of tetryl.

2. Functioning:

(a) When armed — As soon as the bomb is released it is free to arm. When rotation of the bomb has reached about 1500 r.p.m., centrifugal force arms the fuze and it will function on impact. When the projecting head of the firing pin comes in contact with any object having an appreciable resistance to impact, such as the surface of an airplane wing, the firing pin is momentarily retarded while the fuze and bomb continue in their flight, causing the firing pin to puncture the disc and stab the detonator, thus exploding the detonator which in turn sets off the booster and the burster charge of the bomb.

(b) Air travel required to arm — Near sea level the bombs require about 1500 feet of air travel along the trajectory to reach a spin rate sufficient to arm the fuze. At 20,000 feet altitude about 3,000 feet of air travel is required for arming.

(c) Sensitivity — When dropped from sufficient altitude to permit arming, the fuze will function with about .001 second delay on impact with materials, such as the wings or fuselage of an airplane. Sample fuzes are given routine acceptance tests to insure functioning. They must function on impact with water when dropped in AntiAircraft Bombs (spinning type) loaded with granulated TNT. The drops are made from aircraft at an altitude of 1000 feet and sufficient speed (about 100 knots) to insure arming.

To summarize this, it says that the Mark 34 bomb has fins designed to rotate the bomb in air. The Mark 227 impact fuze is armed after the spinner reaches 1500 RPM and detonates after striking a surface with a delay of 0.001 seconds.

Since War Thunder doesn’t model minimum arming distances for bombs and missiles, I think we can assume that the simple answer is that the Mark 34 Anti-Aircraft bomb explodes on impact.

Unfortunately I didn’t see details about the other elements of this weapon but at least this is one piece of the puzzle!

3 Likes

how have I only just seen this, btw we basically already have this in-game since its actually possible to land the p-39 on carriers and take back off