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The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 Bell YFM-1 Airacuda was the first military aircraft produced by the Bell Aircraft Corporation. Originally designated the "Bell Model 1," the Airacuda first flew on 1 September 1937. The Airacuda was marked by bold design advances and considerable flaws that eventually grounded the aircraft.

The Airacuda was Bell Aircraft's answer for a "bomber destroyer

Bomber destroyer

Historically, several aircraft were designated bomber destroyers prior and during the Second World War. They were interceptor aircraft dedicated to destroy enemy bomber aircraft with exceptionally powerful armament...

" aircraft. Although it did see limited production, and one fully operational squadron

Squadron (aviation)

A squadron in air force, army aviation or naval aviation is mainly a unit comprising a number of military aircraft, usually of the same type, typically with 12 to 24 aircraft, sometimes divided into three or four flights, depending on aircraft type and air force...

 was eventually formed, only one prototype

Prototype

A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...

 and 12 production models were ultimately built, in three slightly different versions.

Design and development

In an effort to break into the aviation business, Bell Aircraft created a unique fighter concept touted to be "a mobile anti-aircraft platform" as well as a "convoy fighter." Created to intercept enemy bombers at distances beyond the range of single-seat fighter interceptors, the YFM-1 (Y, service test; F, fighter; M, multiplace) was an innovative design incorporating many features never before seen in a military aircraft, as well as several never seen again. Utilizing a streamlined, "futuristic" design, the Bell Airacuda appeared to be "unlike any other fighters up to that time."

According to Major Alexander De Seversky's 1942 book, Victory Through Air Power

Victory Through Air Power

Victory Through Air Power is a 1942 non-fiction book by Alexander P. de Seversky. It was made into a 1943 Walt Disney animated feature film of the same name: Victory Through Air Power.-Theories:...

, the Bell Airacuda "represents a great engineering achievement. But its designation as 'convoy fighter' is erroneous, since that requires different disposition of armament. With its maximum firepower directed forward, it really offers a preview of an effective long-range interceptor fighter

Interceptor aircraft

An interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...

."

A forward-firing M4 37mm cannon

M4 cannon

The 37 mm Automatic Gun, M4, known as the T9 during development, was a 37 mm autocannon designed by John Browning and used in the Bell P-39 Airacobra and P-63 Kingcobra fighters, as well as experimentally on other designs. It provided interceptors with a weapon that could shoot down any...

 with an accompanying gunner was mounted in a forward compartment of each of the two engine nacelle

Nacelle

The nacelle is a cover housing that holds engines, fuel, or equipment on an aircraft. In some cases—for instance in the typical "Farman" type "pusher" aircraft, or the World War II-era P-38 Lightning—an aircraft's cockpit may also be housed in a nacelle, which essentially fills the...

s. Although capable of aiming the cannons, the gunners' primary purpose was simply to load them with the 110 rounds of ammunition stored in each nacelle.

The crew of five included the pilot and gunners; a copilot/navigator who doubled as a fire-control officer, using a Sperry Instruments "Thermionic" fire control system (originally developed for anti-aircraft cannon) combined with a gyro-stabilised and an optical sight to aim the weapons; and a radio operator/gunner armed with a pair of machine gun

Machine gun

A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....

s stationed at mid-fuselage waist blisters for defense against attack from the rear.

An unusual feature of the Airacuda was the main door for entry. The door was opened and pulled down and hinges folded in on three steps for the crew to climb into the aircraft.

Design flaws

The Airacuda was plagued with problems from the start. The lofty performance estimates were unobtainable as, despite its sleek looks, the Airacuda was heavy and was slower than most bombers. In the event of interception by enemy fighters, the Airacuda was not maneuverable enough to dogfight, while the meager 600 lb (272 kg) bomb load was of little use in the intended fighter-bomber role. Even the centerpiece 37 mm cannon armament was perilous to use. The cannons had a tendency to fill the gun nacelles with smoke whenever fired and, additionally, fears persisted as to how the gunners would escape in an emergency, with the propellers directly behind them. An emergency bailout would have required both propellers to be feathered, though additional provision was made with the use of explosive bolts on the propellers to jettison them in the event of a bailout.

The Allison V-1710-41 engines, though relatively trouble-free in other types, had no additional cooling systems. Like many pusher

Pusher configuration

In a craft with a pusher configuration the propeller are mounted behind their respective engine. According to Bill Gunston, a "pusher propeller" is one mounted behind engine so that drive shaft is in compression...

 designs, they were prone to overheating. On the ground, the aircraft had to be towed to and from the runway and could only be started when the Airacuda was able to take off immediately. Even in the air it was not uncommon to experience overheating problems. Although designed for turbo-supercharging, the first flights were made with V-1710-9 carbureted engines that only delivered 1,000 hp (745.70 kW) each. Despite the long five ft shaft extensions, there were no problems with this feature. When the turbos were fitted to the later YFM-1, they were plagued by cranky turbo regulators that backfired continuously. An explosion during a September 1939 test flight made it apparent that the teething engine troubles would not be solved easily.

Additionally, Marshall Wainwright notes that other sources indicate the first eight aircraft were to originally have been powered by Allison V-1710-13 engines fitted with GE Type B-6 turbosuperchargers. These aircraft were eventually delivered with improved V-1710-23(D2) engines. Wainwright further states that two of the YFM-1 airframes were changed on the production line to accept the V-1710-41 without turbosupercharging, becoming YFM-1Bs. This is noted in a contract change dated 19 October 1939 which shows that aircraft 34-489 and 38-490 had their turbos, all associated ducting, and controls removed and V-1710-41(D2A) "Altitude Rated" engines installed instead. The (D2A) was essentially a -23 with higher supercharger gear ratios (8.77:1 versus 6.23:1), which allowed the motor to develop around 1,090 hp up to 13,200 ft ASL. They used the same ratings and components as the Altitude Rated V-1710-33(C15) Allison fitted to the original Curtiss XP-40. Allison was paid $1,690 to modify each engine.

Initial flight testing by Lt. Ben Kelsey

Benjamin S. Kelsey

Benjamin Scovill "Ben" Kelsey was an American aeronautical engineer and test pilot who brought success in World War II to the United States Army Air Forces by initiating the manufacture of innovative fighter aircraft designs, and by working to quickly increase American fighter production to meet...

 proved the Airacuda virtually impossible to control on a single engine, as the aircraft would go into an immediate spin. Problems with stability in pitch were also encountered, and had to be corrected by reducing power. Test pilot Erik Shilling described his experiences in a later book, Destiny: A Flying Tiger's Rendezvous With Fate as:

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."

The Airacuda was also saddled with a complex and temperamental electrical system and was the only aircraft ever built to rely on an independent auxiliary power unit

Auxiliary power unit

An auxiliary power unit is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft, as well as some large land vehicles.-Function:...

 (APU) to power both engine fuel pumps, as well as all aircraft electrical systems. Systems usually powered by an aircraft's engines were instead powered by the single generator. The generator, with its own supercharger, was located in the belly of the aircraft. In the event of a failure (and they occurred frequently), the crew was instructed to begin immediate emergency restart procedures as the aircraft basically shut down. When the APU failed, the pilot had "NO fuel pressure, NO vacuum, NO hydraulic pressure, NO gear, NO flaps and NO ENGINES".

Accidents

Despite the aircraft's many faults only two were lost in accidents. The seventh aircraft (38-492) was on its final test flight from the Buffalo factory prior to delivery to the Air Corps when pilot John Strickler, a Bell pilot and engineer, and co-pilot Brian Sparks, who was Bell's chief test pilot at the time, encountered problems recovering from a deliberate spin attempt which was part of the test flight profile. Despite every effort to emerge from the spin the aircraft wouldn't respond, and it appeared that the rudder had locked. Co-pilot Sparks shut down the engines and waited for the propellers to come to a stop before bailing out. Because of the tandem seating it was necessary for Sparks to exit the aircraft first, and in doing so he struck the empennage, breaking his legs – and in the process, freeing the rudder. Strickler decided to stay with the aircraft and attempt an emergency landing. By this time the aircraft had lost sufficient altitude that there was not time to restart the engines. Strickler put the Airacuda down hard in a farmer's field, and walked away unhurt. The Airacuda was so badly damaged it had to be scrapped.

All three Airacudas with tricycle landing gear encountered problems and were damaged at one time or another. The most serious accident occurred to YFM-1A (Model 8) 38-497, on a flight from Chanute Field, Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

, and Keesler Field

Keesler Air Force Base

Keesler Air Force Base is a United States Air Force base located in Biloxi, a city in Harrison County, Mississippi, United States. The base is named in honor of aviator 2d Lt Samuel Reeves Keesler, Jr., a Mississippi native killed in France in First World War.-Units:The base is home of...

, Mississippi

Mississippi

Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...

, when a broken oil line started an in-flight fire. The cause of the broken line appeared to be serious airframe vibration encountered during the flight. With no way of extinguishing the fire, both the pilot and crew chief agreed to bail out. The pilot was killed when his parachute failed to deploy (he may have struck the tail while bailing out). This was the only fatality to occur during the flying of Airacudas. The accident investigation report stated "inherent defects in design caused constant maintenance difficulties and the flying of this type has been very limited."

Operational history

Despite these problems, one fully operational Airacuda squadron was eventually assembled, and operated from 1938 until 1940. Funds were appropriated, but never released, for the purchase of two groups of Airacudas. Continuing problems gave the aircraft a reputation as "hangar queens". Towards the end of the type's operational life, the aircraft were flown primarily for photo opportunities and always accompanied by a chase plane

Chase plane

A chase plane is an aircraft that "chases" another aircraft, a spacecraft or a rocket during flight. Safety can be one function of a chase plane; others are to photo or video the target vehicle, or to collect engineering data from it...

 for safety. Eventually the decision was made to disperse the aircraft to various airfields to give pilots an opportunity to add the unusual aircraft to their log books. Airacudas were sent at various times to Langley Field, Virginia; Maxwell Field

Maxwell Field

Maxwell Field was the football stadium located behind the former location of Louisville Male High School, 911 S. Brook St., Louisville, Kentucky, 40203 which was bounded by the streets of Brook, Breckinridge, Floyd, and Caldwell streets in Louisville, Kentucky. In 1984 a double murder known locally...

, Alabama; Hamilton Field, California; and Wright Field

Wright Field

Wright Field was an airfield of the United States Army Air Corps and Air Forces near Riverside, Ohio. From 1927 to 1947 it was the research and development center for the Air Corps, and during World War II a flight test center....

, in Dayton, Ohio. YFM-1 38-488 was displayed at the 1940 World's Fair

1939 New York World's Fair

The 1939–40 New York World's Fair, which covered the of Flushing Meadows-Corona Park , was the second largest American world's fair of all time, exceeded only by St. Louis's Louisiana Purchase Exposition of 1904. Many countries around the world participated in it, and over 44 million people...

 in New York, finished in the markings of the 27th Pursuit Squadron

27th Fighter Squadron

The 27th Fighter Squadron ' is a United States Air Force unit. It is assigned to the 1st Operations Group and stationed at Langley Air Force Base, Virginia....

. During this time the aircraft saw limited flight time, as few pilots were interested in flying the unusual aircraft.

Several plans were made to modify the Airacudas to give them operational status, including modifying the airframe and adding more powerful engines, but all proposals were eventually rejected. In early 1942, despite fears of enemy bomber attacks against which the Airacuda was intended, the aircraft were stricken from inventory.

Variants

The prototype, known as the XFM-1, incorporated a tailwheel, side "blister" ports, and a smooth, rounded canopy. This is the best known, and most produced version. An updated version called the YFM-1A eliminated the side blisters and added externally mounted radiator

Radiator (engine cooling)

Radiators are used for cooling internal combustion engines, mainly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine....

s and turbo-superchargers. Produced in 1940, the final version designated YFM-1B, was slightly larger, had slightly less powerful Allison engines and incorporated a tricycle landing gear. The canopy was redesigned, with a flat forward windshield. A rearward-facing belly gunner's position was also added. The resulting aircraft was roughly the size of a Douglas B-18 Bolo bomber. Three YFM-1Bs were produced in 1939 before production was finally terminated.

XFM-1Prototype powered by two 1,150 hp V-1710-13 engines, one (38-351) built.
YFM-1 Development aircraft powered by two 1,150 V-1710-23 engines and fitted with 37 mm cannon in wing nacelles, eight built, two later converted to YFM-1B.
YFM-1A Development aircraft with tricycle landing gear, three built.
YFM-1B

YFM-1 re-engined with 1,090 hp V-1710-41 engines, two converted from YFM-1.

YFM-1C - proposed variant not proceeded with.

Survivors

By 1942, 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.

Specifications (XFM-1)

See also

External links

• Bell YFM-1 Airacuda.
• Bell YFM-1 Airacuda (1937)
• YFM-1 Manual T.O. 01-110HA-1 Handbook of Instructions of Operations and Flight Instructions for the Models YFM-1 and YFM-1B Multi-Place Fighter Airplane (1940 dated)