Bell P-400 Airacobra

The very stylish, but underachieving Airacobra was the second most numerous American fighter at the start of the war.


Let’s look at what was right, and what was wrong with the little Bell.

Most readers will probably know this type better under its more common designator, P-39.  But a number of Airacobras were produced for the British, then re-acquired by the US after Pearl Harbor.  These aircraft were produced closest to P-39D specifications, but not quite.  The biggest difference being a British ordered 20 mm cannon firing through the propeller hub instead of the 37 mm of the US versions.  The smaller gun had a higher rate of fire and muzzle velocity, in addition to more ammunition.  These slightly different Airacobras were re-designated P-400.


When the type was first ordered by the US, France and Great Britain it looked very promising.  It had a high top speed (390 mph for the prototype), and the engine behind the pilot allowed for concentrated firepower in the nose.  But problems arose quickly, the biggest being the decision to remove the supercharger.  As a new development, the supercharger was not quite reliable.  Every interested party wanted their new plane now, and the US government was not happy about the thought of exporting something so cutting edge anyway.  But this decision led to a sharp drop in performance above 10000 feet, and took about 20 knots off the top speed.


Notice the port side of the plane was named “Pat”, while the starboard is “Wahl Eye II”. This actually wasn’t that uncommon, as Pilots and Crew Chiefs sometimes called their planes by different names.

In late 1941 the British put their Airacobras into action, and they were apparently underwhelmed in every way.  After Pearl Harbor, the US was looking to boost aircraft deliveries quickly.  With the British already threatening to sue Bell for misrepresentation, they happily offered up their order of Airacobras.  The British planes were delivered to American fighter groups in the Pacific so quickly they were still in their British camouflage and markings.  The example seen here has had the markings painted over, but is still in British colors.  It flew with the 8th Fighter Group in New Guinea, 1942.


Only one American made ace in the Airacobra (Lt William F Fielder Jr. 5 kills).  Those who did score kills in the type wore it as a special badge of honor.  Its speed (at low altitude only) and firepower were considered its greatest strengths.  Poor overall handling, especially spin characteristics; and its complete lack of high altitude performance were considered its biggest drawbacks.  The Russians wound up as the type’s largest operator, and were actually quite fond of it.  But we’ll save that story for another day!


One excellent book I read by a pilot flying the Airacobra is “Angels Twenty” by Edwards Park.  This is a war time biography by a pilot who flew in the south Pacific, mainly New Guinea.  He described the plane as “really good at taxiing”, and stated the airport taxiways were the type’s native habitat.  When airborne, it was clear the Airacobra wanted nothing more than to return to the Earth.  This is in marked contrast to the Thunderbolt he flew later in the war, which he described as a plane that just loved being in the air.


This example is from the Hasegawa kit, and has Aeromaster decals.

About atcDave

I'm 5o-something years old and live in Ypsilanti, Michigan. I'm happily married to Jodie. I was an air traffic controller for 33 years and recently retired; grew up in the Chicago area, and am still a fanatic for pizza and the Chicago Bears. My main interest is military history, and my related hobbies include scale model building and strategy games.
This entry was posted in Fighter, USA and tagged , , . Bookmark the permalink.

14 Responses to Bell P-400 Airacobra

  1. Theresa says:

    That is a great epitaph the Plane wanted to return to the ground as quickly as possible.

  2. Terry Brodin says:

    Amazing how an aircraft can be so good looking and suffer so on performance — but it did find its niche!
    George Welch wasn’t particularly fond of the P-39 and when asked about what he liked about it, he replied “Well, its got 12 hundred pounds of Allison armor plate.”
    Your P-400 looks great in the RAF paint scheme. The undersides “Sky/Sky type S” color has always fascinated me. Depending on the lighting, its powder blue, light gray or a greenish grey.

    • atcDave says:

      That’s a funny quote, may say a lot about what he thought of the Allison engine too! I believe he had two kills in the type? He was definitely a significant American ace, with kills in the P-40 and P-38 as well; so his cynicism is meaningful.
      The few pilots I’ve seen who liked the type only flew it in training (like as their first high performance type) or rear areas (like The Canal Zone). Edwards Park’s autobiography is a great read, he not only hated the P-39, he was convinced his particular airplane (“Nanette”) was chicken. But he just loved the Thunderbolt.

      British Sky is an interesting color. The Brits had very detailed and exacting rules for aircraft paint (the “S” part is the requirement for a very smooth, low drag texture) and finish. Probably the most exacting of any WW2 combatant. For me, as a modeler, it’s a mixed blessing. The good of it is it’s fairly easy to research colors and markings. The bad is, if I take any liberties I’m wrong with no excuses!
      The Lend Lease aircraft can get a little tricky. American companies were allowed to use nearest equivalents on the paint colors, but the British still expected a precise and low drag finish. If memory serves, I think Bell was using a naval color (Gull Grey) as a substitute for Sky. But the funny thing is, the British often rejected the American paint schemes as too sloppy and stripped and repainted the aircraft. At least in the early war years this happened a lot, by 1943 or so they got a lot less picky.
      It’s amazing how much time I’ve spent just reading about color!

      • Terry Brodin says:

        For years I have argued with friends that Sky Type “S” was not a different color from Sky, but as you pointed out, a texture designation. Thank you!
        I agree that the British had detailed and exacting rules, but the Luftwaffe seemed to have had an obsession for more and more complex camouflage schemes!
        Researching colors and camouflage schemes can be a hobby onto itself!
        I had my doubts that Lend Lease aircraft would be held to British paint specifications — especially interiors. Then I came across a color photo of a RAF Lockheed Hudson with the entry door open and it was not any US interior color, but the British Interior Grey-Green. Guess it depended on how far a manufacturer was willing to go.
        You familar with the movie “Mr Blanding’s Builds His Dreamhouse”?i
        There’s a scene where the wife is painstakenly describing the color matches for each room with the painter foreman contractor hanging on her ever word, reassuring her he understands exactly. When she leaves, he turns to his worker and they agree — white, green, blue and red. I’m sure thiis scene was first played out by an aircraft manufacturer representative!
        As far as “taking liberties”, I feel if you are “in the ballpark”, its fine.
        A model of a P-47 with any shade of dark green is acceptable. It’s nice to get as close as you can, but as long as it conveys the cockpit was a dark green, close enough is sufficient. It’s not like you painted the cockpit a totally wrong color like modern Russian Blue-Green.
        What I find it hard to stomache is a fluorescent zinc-chromate green cockpit! That just won’t seem to go away!

      • atcDave says:

        The “Type S” name does generate controversy! Even in wartime sources there is some debate, which may indicate a number of wartime aircraft were actually painted “wrong”. Which of course is part of the fun in modeling; figuring out what, if any, spec your subject is following.
        But as near as I can tell, “S” for “smooth” is the most official definition.

        You’re completely right about the American builders, there’s a huge range of how compliant they chose to be to British specs. It could even vary from factory to factory; a Mustang III built in Burbank might have different colors from one built in Dallas (or is that “colours” if they’re following British specs!). And as I mentioned, a depot or forward unit might chose to redo the whole thing anyway.
        German camo is particularly interesting. Although the colors were fairly standardized, patterns were almost always depot applied or modified. Its almost impossible to build any subject without good photos, and that may be part of why German subjects generate so much interest among modelers. The number of different camoflauge schemes is almost one to one with the number of planes built! (yeah, I’m exagerating a little!)
        Some of their late war colors get harder to guess as their industrial standards slipped.
        Japan is also fascinating. There’s a definite difference between manufacturers, and some types, like the Zero, were built by different manufacurers with no difference in designation. Like Germany, there was also a decrease in paint quality as the war went bad for them. Its amazing how useful a reference like “Japanese Aircraft Interiors” can be (do I expose myself as a nerd to admit I loved that book!).

        When painting, I usually try to start as close to the factory specs as I can for any color. Obviously I improvise as needed for any number of reasons, and weather based on age and environmental issues.
        The old “Chromate Green” thing is funny. I remember as a kid I put that color on every interior! It was probably the first interior color I ever knew. I think by High School I knew that other countries used different colors. But it wasn’t until I got into this as an adult I realized it was even more complex yet; like how Chromate Yellow, Chromate Green, Interior Green and Black might all be on the interior of one aircraft. And that Bell and Republic had their own interior shades. And, just, oof. I try to follow specs, but keep an open mind on variations.

        It makes me laugh how much I can write now about colors. But hey, you started it!

      • atcDave says:

        And yeah I’ve seen “Mr. Blandings Builds His Dreamhouse”. That’s a family favorite for us. My wife is an Interior Designer and she laughs so hard at that one! Great movie.

  3. Pierre Lagacé says:

    Another one Dave

  4. Ron Boren says:

    The Bell should have kept the B-5 turbo secretly, and when it was refined, do a demonstration mock dogfight.
    The P-400 export version was denied even the standard supercharger, if I’m not mistaken.
    The RAF should have converted these with a Mk II Hispano 20mm cannon in place of the US reject version; and a Merlin in place of the Allison. They changed the US 0.30 Cal wing guns to their own 0.303 but stopped there. Why not tackle the bigger problems? Just the decent cannon and high altitude engine would’ve transformed this fighter into a winner and the RAF could school the USAAC with their competent interceptor.

    The XP-39 prototype did 398 mph without guns and climbed to 20,000′ in 5 minutes or less.
    The P-400 in the RAF did 355 mph with guns and climbed to 20,000′ in 15 minutes!
    You can see why the RAF wanted to sue for false advertising. The added guns didn’t account for that much difference. It’s the turbo-supercharger. True, it was cutting edge and unrefined, but look at the alternative. These P-400s were originally destined for France which fell, so got diverted to the UK. At that point they were safe from the enemy. They should not have been without the standard P-39 superchargers (as if the Bf 109 might improve by capturing it). So the P-400 wasn’t as bad as the P-39, it was worse!

    The what if? solution of the cannon and engine conversion could go a bit further too.
    The P-400 had short combat radius like all P-39s. Another flaw was the extra long take-off run.
    This complicated missions logistics. On top of that, gun reloading and maintenance took forever due to lack of access. These 3 problems could be easily solved:
    1. Swap the wing guns for added fuel for better combat radius.
    2. Swap the nose-wheel for a tail-wheel. The Bell Navy XFL-1 version of the Cobra was a tail dragger and was airborne from carriers! Take-off run was perhaps the best thing about it.
    3. Enlarge the panels for quicker servicing.
    Mission planning would not be limited to long airfields too close to the front, with only half the
    P-400s ready to go.

    This brings us to the accident rate. Poor directional stability was not helped by reducing the span of the XP-39 for speed and then adding a ton more weight. The added length made it tail heavy. This lends itself to swapping the nose-wheel for a tail-wheel as well. Any additional P-400s sent from Bell could have the 1′ bigger wings of the Bell XFL-1, but keeping the strong main-wheels unchanged, and the wing scoops intact for speed vs the under-wing scoops that slowed the Airabonita too much. The 232 S.F. wing would help handling stability, as well as allow even more fuel for range, which was about 1,000 miles clean for the XFL-1. This is assuming the RAF liked a P-400 with a RR Merlin and their own cannon and wanted more. If they really like their RAF cannons, they could put 2 more Mk II Hispanos in the wings and still have decent range. If that makes it too heavy, the cowl guns could go. These fifty Cals. had up to 60% reduction in RoF anyway.
    The spin problem could be managed by adjusing the placement of the 3 cannons and their ammo.
    The P-39 was notorious for turn-spin after the 30 rounds of 37mm ammo were spent, magnifying the tail-heavy bias beyond trim margins. The 20mm in the nose could be pushed forward to the limit and nose-ammo increased so as not to run out before the wing cannons. Then return to base with some ammo left. The wing ammo could be behind the ‘cg’ to offset the nose ammo spent. If They prefer to keep the wings gun-free and keep the 0.50 Cals, the same can be done with the cowl gun ammo, moving it behind the ‘cg’ straddling the pilot with long barrels. Muzzles could be in the chin position like the early Mustang. This would mean much less firepower but better roll-rate, agility, speed, climb, and safer turn-stall, I would do both depending on enemy fighters or bombers.

    • atcDave says:

      Some very interesting comments Ron! Like so many wartime projects there is always the possibility they were abandoned too soon in the rush to get things built. How the Airacobra would have performed with a Merlin is certainly intriguing “what if”.
      And really, Bell did eventually get it right with the P-63. That really did deliver on the Airacobra’s promise. But at that point other types, especially Thunderbolt and Mustang offered equal or better performance. Which sort of begs the question, could a different improvement program have delivered a better package any sooner? I would guess not, but it is fun thinking on such fantasy projects. I’d love to see a scale model of your proposal!

      • Ron says:

        Thanks for the feedback.
        The RAF had the chops to do justice to the P-400.
        I can’t excuse them for not trying their 20mm Hispano Mk II cannon in place of the US M1 version at the very least. Fail rate: 1 per 1,500 vs 1 per 40 rounds for the M1.

      • atcDave says:

        Yeah I’ve heard that gun was one of the least popular aspects of the plane.
        It’s interesting too though that the Soviets had good success with various Airacobras models, even (depending on who we believe!) to say some writers consider it one of their more effective types. The Luftwaffe even showed some respect for Soviet Airacobras, well, as much respect as they ever showed for anything Soviet.

  5. ARadnom says:

    P-400 … a P40 with a zero on its tail.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s