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Airacuda XFM-1 (Experimental Fighter Multiplace)

The XFM-1 was an exciting design. The Airacuda was the first military aircraft produced by the Bell Aircraft Corporation. By 1941, the Bell product line consisted of the AIRACUDA, the P-39 AIRACOBRA [a much maligned but arguably successful aingl-engine combat airplane], and the XFL-1 AIRABONITA [an experimental shipboard interceptor developed largely along with the P-39 except that it had a tailwheel undercarriage rather than a tricycle landing gear]. The Airacuda was the first plane on which 37 mm. guns, two of them, each firing forward from an engine nacelle, were mounted. It was troublesome to fly and maintain, and was not put into mass production.

This machine was the largest fighter flying [as of 1940] and is among the first to be designed with cabin supercharging in view. Originally called the "Bell Model 1," the Airacuda first flew on the first of September 1937. It was a rather large mono–plane powered by two pusher prop engines with a crew station in each engine nacelle. It had a crew of five and was armed with six guns: two forward–firing in the nose; one forward–firing in each engine nacelle; and two flexible waste guns. The problem was that the XFM–1 lacked the required performance to be useful. The XFM-1 was to prove one of the most disappointing technical and tactical failures of the pre-World War II period.

After the maneuvers of 1933, Colonel Arnold had concluded that one-seaters were ineffective against bombers and had therefore recommended to the Chief of the Air Corps that a multiseater be developed without delay. Captain Claire Chennault, a leading advocate for pursuit aviation, lamented the state of American pursuit aviation in the years just following the Great War. But American pursuit aviation advanced rather rapidly throughout the decade. Within a few years American pursuit aircraft had advanced to a point where they were on par with rest of the world. By the mid-1930s, many claimed that escort was entirely unnecessary. This was due to the fact that bomber performance outmatched that of existing pursuits.

Unless pursuit speed was 40% to 50% greater than that of bombers, pursuit was useless. It was claimed that while the means of stopping bombers did not exist in 1936, the requirement still existed and that efforts to develop pursuit were needed. Unofficially, few in the Air Corps believed that it was technically possible to develop interceptor pursuit with the required speed, or an escort fighter that had both the range and speed to match the bombers. Many in the Air Corps doubted that technology could bring pursuit performance up to that of the bombers.

The first, half–hearted recommendations for escort research came from the Air Corps Board study number two, Multi–Engine Fighter Aircraft, 15 July 1935. It recommended that an experimental fighter be developed from an “existing type” for escort, “but only if it did not interfere with the progress of other branches of aviation until the need for an escort plane was demonstrated thoroughly.”

The Air Corps gained experience with two–place pursuits in the early 1930’s with the P–16 bi–plane and the P–30 mono–plane. The P–16 had a gunner sitting backwards behind the pilot to shoot aircraft coming in from the rear. The 1st Pursuit Group was unhappy with their 25 P–16s, labeling the rear gunner as useless. The Consolidated P–30 also had a rear gunner, but flight test proved the gunner to be not only useless, but had a tendency to black out during sharp turns.

Chennault doubted the feasibility of building a militarily useful multi–seat fighter. “Since the interceptor must have a margin of speed over the bomber, we are confronted with the technical impossibility of building an airplane very similar in characteristics to a bomber but considerably faster than a bomber". Chennault recommended, instead, that a superior single-seater be developed to meet the interception requirement. For this purpose he outlined the desired specifications, including an in-line, water-cooled engine, which were later to be realized in the Curtiss P-40-the plane that became the backbone of Chennault’s fighter units in China during World War II.

In 1935, the leadership of the famous American aircraft manufacturer Consolidated Aircraft Corporation decided to move the headquarters and production from the city of Buffalo to San Diego. But not all employees agreed to relocate. Among them were vice-president of Consolidated Larry Bell, his assistant R. Whitman and chief engineer R. Wood. They became the founders of the new company, which was named "Bell Aircraft."

The Secretary of War urged "most serious consideration" of a multi–seat fighter that would serve equally well as a fighter, bomber, and reconnaissance plane, because it would be cheaper if one plane could perform all the functions of military aviation. The result was the 1935 Bell XFM-1 Airacuda program. It is rather difficult to understand how aviation experts could have taken this proposition seriously, since all experiments with multiplace pursuit, going back to World War I, had been unsuccessful. Perhaps one reason for the support of the idea was the fact that it appeared to the General Staff to be a possible means of reducing the number of Air Corps types, a policy consistently encourages by the War Department in the interest of standardization, quantity production, and economy.

Beginning with the assumption that “present and potential single-engine pursuit planes are wholly ineffective against bombardment aircraft,” the statement describing the Bell design (later to become the XFM-1, “Airacuda”) claimed that the proposed model would serve not only as a successful interceptor, but also as an all-purpose fighter, bomber, observation, and attack plane. In November 1935 the Secretary of War approved the characteristics for this experimental plane; its primary mission was to be “sustained attack of hostile aircraft in flight,” but “The idea should be kept in mind of a several purpose airplane capable of replacing various other types now authorized.”

In 1936 the Materiel Division at Wright Field held a design competition for an interceptor aircraft. Lockheed submitted a design which later evolved into the P-38, Bell came in with a highly original design which it called the XFM-1, X for experimental, F for fighter, M for multiplace. This twin-engine aircraft had 37-mm forward-firing cannon mounted in the engine nacelles but no rear-firing armament. It was expected to be so fast it could overtake bombers, destroy them with its cannon from a safe distance, and then rely upon its speed to elude hostile pursuit.

The Lockheed design was evaluated at Wright Field as better engineered, but the Bell submission won the competition, largely because of the impressive potential of those twin cannon. Bell signed a contract for the construction of a single prototype, pre-assigning it the serial number 36-351. A minor misunderstanding occurred with the awarding of a military designation, as the name FM-1 was also going to be given to the Grumman F4F-3 marine fighter, the production of which was set up by General Motors. Two planes with the same name were too much, and one of the fighters would have to part with it.

By the end of 1937 the paper design submitted by Bell had been reduced to practice as a flyable aircraft, the experimental XFM-1. The plane showed sufficient promise to warrant procurement of a service test order of thirteen items, but these were to be rather extensively modified to include rear-firing guns and a number of other features substantially changing the design.' It was expected that the YFM-1 would be used to accompany the heavy B-17 bombers, the serial production of which was only being developed.

Early in 1938, before the service test model had yet come off the assembly line, General Westover was boasting about the aircraft to Congress. "The XFM-1," he said, was "probably the most formidable fighting weapon of its type yet developed." A year later, with the service test models still not yet received from the contractor, his successor, General Arnold told a congressional committee that this airplane was "the most striking example of development" in the past year "anywhere in the world." This hyperbole may seem innocent enough, but it prompts one to ask just what the Chief of the Air Corpsknew or did not know at this time about the Mitsubishi Zero or the Messerschmitt 109.

Despite early failings, the USAAC allowed the XFM-1 product to continue when it awarded another contract during May of 1938 for thirteen test aircraft under the designation of "YFM-1". Without waiting for service tests to verify his expectations, General Arnold continued to assure the U.S. public that with the XFM-1, the Air Corps had "jumped to an early lead." To substantiate his claim, he quoted a British magazine as saying that "the new Bell fighter is the coming thing. The technical department of every air force in the world would give a lot to have 48 hours alone with this machine." More curious than this reliance on journalistic puffery, was Arnold's assertion that the XFM-1 would have sufficient range "to accompany and defend our bombardment formations on long raids."

Aside from the fact that no solid evidence of the actual, as opposed to the design, range of the FM-1 was yet available, this reference to bomber escorts contradicted the contentions of the Air Corps officials over the past several years that bombers were so fast and so well defended, they no longer required fighter escorts.

Chennault fought unsuccessfully against the Wright Field experts on this question of multiplace fighters. He referred to the XFM-1 contemptuously as a plane having no tactical use, but the engineers, Chennault said, “were fascinated with the intricacies of its construction.” The judgment may be harsh and unfair, but Chennault has been vindicated in his criticism of the plane and the idea of multiplace pursuit.

Comparison of XFM–1 performance with the contemporary XP–37 showed the multi–seater far behind in speed, climb, and ceiling, while the single–seater was far less expensive to build and operate. Not only was the Airacuda’s speed insufficiently greater than the bombers it had to catch, but the big fighter’s lack of maneuverability would have made it easy prey for single–seat escorts attacking from the rear. Nor did the unwieldy arrangement recommend itself for protecting bombers against light interceptors.

The XFM–1 Airacuda was supposed to be a superior interceptor as well as an all–purpose fighter, bomber, observation, and attack plane. The XFM–1 was to prove [tobe] one of the most disappointing technical and tactical failures of the pre–World War II period. It apparently was a case of ‘too much engineering and too little tactics.’ Amazingly, despite the obvious shortcomings, Air Corps ordered twelve of the aircraft, wrongly viewing it as a capability that could both destroy enemy bombers and escort friendly bombers. It could do neither and never saw combat.

What makes General Arnold's rhetoric so curious is the simple fact that the FM-1 Airacuda, as it was called, never remotely lived up to the Chiefs careless and, indeed, unjustified assertions. Even when one discounts the inevitable bugs which plague all new model aircraft, the FM-1 never came close to its intended 300-mph top performance and thus lacked the speed differential so essential for an interceptor. Moreover, it lacked maneuverability, not to mention an inferior rate of climb and ceiling.

Despite its good aerodynamics, the fighter was heavy and slow, like most bombers: in case of enemy fighter aircraft, Airacuda was not maneuverable enough to conduct an air battle. While a meager 600-pound (270-kilogram) cargo of bombs was of little use in the alleged role of a fighter-bomber. Even the main highlight of the project - 37-mm guns were dangerous for use: they had a tendency when firing to fill gondolas with smoke. In addition, the pusher propellers were a serious danger for the gunners when leaving the plane in the event of an emergency. The two crew members in the nose risked hitting the tail or getting chopped up by the propellers, but at least they had a chance of making it. However, he two gunners, stuck in those nacelles, had no chance at all.

It couldn't actually taxi, as the engine cooling system only worked in flight, so it had to be towed around on the ground. Airacuda was also burdened with a complex and capricious electric system and was the only aircraft ever built, depending on the auxiliary power plant (APU) when not only the entire electrical system but also the fuel pumps of both engines were activated. Systems, usually driven by aircraft engines, were activated by a single generator. The generator, with its own supercharger, was located in the fuselage. In the event of his refusal (which was not uncommon), the crew according to the instructions was to immediately begin emergency restart procedures, as all the aircraft systems ceased to operate.

Test pilot Erik Shilling related "Flying the Bell Airacuda was a new experience for me, since it was the first pusher aircraft I'd ever flown. Its handling characteristics were foreign to anything I had ever had my hands on. Under power it was unstable in pitch, but stable with power off. While flying straight and level, if a correction in pitch was required, a forward push on the control resulted in the airplane wanting to pitch over even more. Pitch control became a matter of continually jockeying the controls, however slightly, even when the aircraft was in proper trim. The same applied if pulling back on the control. It would tend to continue pitching up, requiring an immediate corrective response. The same happened in a turn with power off, the Bell became stable in pitch. This was fortunate because during approach and landing, it was very stable, and a nice flying airplane."

Major design flaws and a problematic operational history gave the aircraft a reputation for being a "hangar queen." The optimistic and complex aircraft provided a myriad of challenges for Bell personnel througout its brief life. The plane was not a favorite among test pilots charged with flying the machine nor ground crew charged with its upkeep and repair. Near the end of its run, the FM Airacuda was primarily used for photo opportunities; always being accompanied by a chase plane for safety. Later the Airacudas were dispersed to various airfields so that pilots could fly the strange aircraft and add it to their log books. The FM Airacuda was displayed at the Bell exhibit at the 1940 World's Fair in New York.

With few pilots interested in flying the strange aircraft, the Airacuda saw limited flight. The YFM-1 did not achieve a first flight until September 28, 1939 - some two years after XFM-1 first flew. The second flight suffered damaged when one of the turbosuperchargers fell apart in-flight but the program was eventually passed on to airmen for formal testing from February of 1940 onwards. The YFM-1 deisng provided nine aircraft coming in 1940. Three more were delivered into October with rather forward-thinking tricycle undercarriages - a modern approach revisited by Bell in their P-39 fighter. These aircraft carried the designation of "YFM-1A". Two other Airacuda aircraft of the batch appeared with Allison V-1710-41 engines of 1,090 horsepower output though they lacked turbosuperchargers. They were designated "YFM-1B" and emerged from the existing YFM-1 stock. In December 1940, it as reported that the 10-ton twin-engined Bell Airacuda fighter (Allison V-1710's in pusher installations), with which many difficulties had been had, and which had been dropped by the Army, had been revived. Three somewhat different Airacudas were being tested at Wright Field, and a production order for one of the types was anticipated.

Major Alexander Nikolaievich Prokofiev de Seversky, one of the most influential proponents of the use of strategic air power in warfare, wrote in his 1942 book "Victory Through Air Power" [which became a bestseller and a movie] "Bell Airacuda represents a great technical achievement, but its designation as an" escort fighter "is erroneous, as this requires a different armament location." With maximum firepower directed forward, this aircraft will become an effective long-range interceptor fighter."

Little had been said by the Army about the aircraft since it was conceived, but General Arnold was known to remark that it as the "smoothest desgned ship that have ever seen and we expecet great things from this airplane". In September 1941, Brig. Gen, George C. Kenney, assistant chief of the Material Division at Wright Field, said the aircraft "is by no means through as far as the Army is concerned. There has been a lull in development, perhaps, but that has been for a period in which we had to iron out the bugs. After all, the ship is of radical design and many new changes developed from the original model before we began to get teh kind of performance out of it that we wanted".

Service trials began during 1941. One example had already been lost during a forced landing brought about by a locked rudder - no fatalities were recorded but the airframe was wrecked. Another airframe was lost in an accident occurring during January of 1942.

Although there were plans to modify the Airacuda's airframe and installing more powerful engines the FM Airacuda was removed from inventory despite the fears of bomber attacks which the Airacuda was designed to prevent. The Airacudas were shunted aside in January 1942, some with as little as 15 hours in the log. All nine surviving YFM-1 airframes were flown by ferry crews to a training facility at Chanute Field, Illinois where the aircraft were assigned to the 10th Air Base Squadron to be used for ground crew instruction. By March 1942, all Airacudas were scrapped. Even Larry Bell's laudatory biographer had to admit that the FM-1 was stillborn.

Better twin engine options eventually became available when the single-seat Lockheed P-38 "Lightning" made its appearance. The heavily-armed P-61 "Black Widow" was the United States' first aircraft specifically designed as a night-fighter. The P-61 carried radar equipment in its nose that enabled its crew of two or three to locate enemy aircraft in total darkness and fly into proper position to attack.