The Martin AM Mauler (originally XBTM) was a single-seat

carrier-based Carrier-based aircraft, sometimes known as carrier-capable aircraft or carrier-borne aircraft, are naval aircraft Naval aviation is the application of military air power by navies, whether from warships that embark aircraft, or land base ...

attack aircraft An attack aircraft, strike aircraft, or attack bomber is a tactical military aircraft that has a primary role of carrying out airstrikes with greater precision than bombers, and is prepared to encounter strong low-level air defenses while pre ...

built for the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

. Designed during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

, the Mauler encountered development delays and did not enter service until 1948 in small numbers. The aircraft proved troublesome and remained in frontline service only until 1950, when the Navy switched to the smaller and simpler

Douglas Douglas may refer to: People * Douglas (given name) * Douglas (surname) Animals *Douglas (parrot), macaw that starred as the parrot ''Rosalinda'' in Pippi Longstocking * Douglas the camel, a camel in the Confederate Army in the American Civil ...

AD Skyraider The Douglas A-1 Skyraider (formerly known as the AD Skyraider) is an American single-seat attack aircraft in service from 1946 to the early 1980s. The Skyraider had an unusually long career, remaining in front-line service well into the Jet Age ...

. Maulers remained in reserve squadrons until 1953. A few were built as AM-1Q electronic-warfare aircraft with an additional crewman in the fuselage.

Design and development

In the 1930s and early 1940s, the Navy divided

carrier Carrier may refer to: Entertainment * ''Carrier'' (album), a 2013 album by The Dodos * ''Carrier'' (board game), a South Pacific World War II board game * ''Carrier'' (TV series), a ten-part documentary miniseries that aired on PBS in April 20 ...

-borne bombers into two types: the

torpedo bomber A torpedo bomber is a military aircraft designed primarily to attack ships with aerial torpedoes. Torpedo bombers came into existence just before the First World War almost as soon as aircraft were built that were capable of carrying the weight ...

and the

dive bomber A dive bomber is a bomber aircraft that dives directly at its targets in order to provide greater accuracy for the bomb it drops. Diving towards the target simplifies the bomb's trajectory and allows the pilot to keep visual contact through ...

, each with crews of two or three men. Wartime experience showed that pilots could aim bombs and torpedoes without assistance from other crewmembers as well as navigate with the aid of

radio beacon In navigation, a radio beacon or radiobeacon is a kind of beacon, a device that marks a fixed location and allows direction-finding equipment to find relative bearing. But instead of employing visible light, radio beacons transmit electromagne ...

s and the development of more powerful engines meant that faster aircraft no longer needed a rear gunner for self-defense. Furthermore, the consolidation of the two types of bombers greatly increased the flexibility of a carrier's air group and allowed the number of fighters in an air group to be increased. In 1943, the US Navy invited proposals for a new multi-purpose bomber and selected four designs in September: the Curtiss XBTC, Douglas XBT2D Skyraider,

Kaiser-Fleetwings BTK The Kaiser-Fleetwings XBTK was an American dive and torpedo bomber developed by Kaiser-Fleetwings for the United States Navy starting in 1944. After only five examples had been built, with the first two being flying prototypes; the contract was ...

and the Martin XBTM. Martin was tasked to provide a backup to the Curtiss design which had been selected as a replacement to the

Curtiss SB2C Helldiver The Curtiss SB2C Helldiver is a dive bomber developed by Curtiss-Wright during World War II. As a carrier-based bomber with the United States Navy (USN), in Pacific theaters, it supplemented and replaced the Douglas SBD Dauntless. A few surviv ...

. Due to the US Navy's concern that the Curtiss design was overly complex and that the company's record was particularly poor during the Helldiver's development, Martin was instructed to create an "unexperimental" design that would be a reliable platform for the Pratt & Whitney R-4360 Wasp Major

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ...

that powered both aircraft. Two prototypes were ordered from Martin on 31 May 1944 with the internal designation of Model 210.Swanborough & Bowers 1990, p. 358. The XBTM-1 was a low-wing, all-metal

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

with folding wings to allow more compact storage in carrier

hangar A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish ...

decks, and

conventional landing gear Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Term ...

. Its fuselage was an oval-shaped stressed-skin

semi-monocoque The term semi-monocoque or semimonocoque refers to a stressed shell structure that is similar to a true monocoque, but which derives at least some of its strength from conventional reinforcement. Semi-monocoque construction is used for, among ot ...

with the single-seat

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the controls that e ...

and its teardrop-shaped

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an ...

positioned just aft of the air-cooled engine. Just behind the cockpit was a fuel tank. The large wing consisted of a two-

spar SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...

center section with hydraulically folded three-spar outer panels. A large dive brake was positioned on the trailing edge of the wing. When closed it could be lowered for use as a landing flap or it could be split into alternating upper and lower sections, with intermeshing "fingers" for use in its intended role. It was very effective in this role, mainly due to its great surface area, but this was at the cost of the width of the

aileron An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around ...

s, which significantly reduced their efficiency. A pair of fuel tanks were positioned in the

roots A root is the part of a plant, generally underground, that anchors the plant body, and absorbs and stores water and nutrients. Root or roots may also refer to: Art, entertainment, and media * ''The Root'' (magazine), an online magazine focusing ...

of the center section. All fuel tanks were self sealing and the pilot and

oil cooler Oil cooling is the use of engine oil as a coolant, typically to remove surplus heat from an internal combustion engine. The hot engine transfers heat to the oil which then usually passes through a heat-exchanger, typically a type of radiator kno ...

were protected by of armor. AM-1s armed

The fixed armament of four T-31 autocannon was fitted in the center section, adjacent to the outer wing panels with 200 rounds per gun. A centerline

hardpoint A hardpoint is an attachment location on a structural frame designed to transfer force and carry an external or internal structural load, load. The term is usually used to refer to the mounting points (more formally known as a weapon station or ...

and a pair of outer hardpoints were installed on the center section and rated to take bombs, fuel tanks or torpedoes up to in weight. The outer hardpoints could also carry an AN/ APS-4 search radar in a pod. A dozen hardpoints could be installed on the outer wing panels to carry bombs or

High Velocity Aircraft Rocket The High Velocity Aircraft Rocket, or HVAR, also known by the nickname Holy Moses, was an American unguided rocket developed during World War II to attack targets on the ground from aircraft. It saw extensive use during both World War II and th ...

s. In service, the Mauler earned the nickname "Able Mable" because of its remarkable load-carrying ability, once lifting of ordnance (three torpedoes, a dozen 250-pound bombs plus its 20 mm guns and their ammunition) on 30 March 1949, perhaps the heaviest load ever carried by a single-engine, piston-powered aircraft. The first XBTM-1 made its

maiden flight The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets. The maiden flight of a new aircraft type is alw ...

on 26 August 1944Andrews & Boyne 1974, p. 12. and began flight testing after it reached the

Naval Air Test Center Naval Air Station Patuxent River , also known as NAS Pax River, is a United States naval air station located in St. Mary’s County, Maryland, on the Chesapeake Bay near the mouth of the Patuxent River. It is home to Headquarters, Naval Air Sys ...

on 11 December. The Navy ordered 750 more aircraft on 15 January 1945, although this was reduced to 99 aircraft after the

surrender of Japan The surrender of the Empire of Japan in World War II was announced by Emperor Hirohito on 15 August and formally signed on 2 September 1945, bringing the war's hostilities to a close. By the end of July 1945, the Imperial Japanese Na ...

in August. The second prototype made its first flight on 20 May. Initial flight tests conducted with the first two prototypes revealed significant problems with the engine, its

cowling A cowling is the removable covering of a vehicle's engine, most often found on automobiles, motorcycles, airplanes, and on outboard boat motors. On airplanes, cowlings are used to reduce drag and to cool the engine. On boats, cowlings are a cove ...

, the

vertical stabilizer A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...

and

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adve ...

. In response, the cowling was lengthened and the engine mount was canted two degrees to the right to offset the engine's tremendous

torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...

. The length of the

carburetor A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meteri ...

airscoop was extended and the propeller

spinner Technology *Spinner (aeronautics), the aerodynamic cone at the hub of an aircraft propeller * Spinner (cell culture), laboratory equipment for cultivating plant or mammalian cells * Spinner (computing), a graphical widget in a GUI * Spinner (MIT Med ...

, rudder, and the vertical stabilizer were redesigned. In April 1946 the aircraft designation was changed to AM-1 when the Navy replaced its Bomber-Torpedo classification with Attack, well before the redesign was completed in early 1947. First deliveries began in March 1947 and a flight test program began that month that lasted three years before the major deficiencies identified were fully corrected. Carrier landing trials revealed a structural weakness of the rear fuselage when one aircraft was broken in half during a heavy landing. Severe vibrations in the tail upon engaging the arresting wire were cured by adding a

roller bearing In mechanical engineering, a rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements (such as balls or rollers) between two concentric, grooved rings called races. The relative m ...

to the tailhook to counter the sideways forces placed on the tailhook. Other necessary changes were the addition of

spoiler Spoiler is a security vulnerability on modern computer central processing units that use speculative execution. It exploits side-effects of speculative execution to improve the efficiency of Rowhammer and other related memory and cache attacks. ...

ailerons and an

elevator An elevator or lift is a cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or decks of a building, vessel, or other structure. They ...

control boost to improve the aircraft's poor controllability at low speeds. In addition, the cockpit layout was unsatisfactory and had to be redesigned. The NATC finally deemed the Mauler acceptable for carrier landings in August 1948 even though aircraft had been issued to one squadron earlier in the year and a new batch of 50 aircraft had been ordered in May. Despite all the modifications to the aircraft over its short life, it remained a maintenance nightmare, especially the leaky hydraulic systems. Martin AM-1Q NAS Glenview

The AM-1Q was developed for

electronic countermeasures An electronic countermeasure (ECM) is an electrical or electronic device designed to trick or deceive radar, sonar, or other detection systems, like infrared (IR) or lasers. It may be used both offensively and defensively to deny targeting info ...

duties. The fuselage fuel tank was removed to make room for the electronics operator and his equipment in a windowless compartment. The aircraft carried several radio and radar receivers, transmitters and a signal analyzer. The operator could also drop bundles of

chaff Chaff (; ) is the dry, scaly protective casing of the seeds of cereal grains or similar fine, dry, scaly plant material (such as scaly parts of flowers or finely chopped straw). Chaff is indigestible by humans, but livestock can eat it. In agri ...

through a chute to block radar signals. Pilots found the Mauler a heavy handling aircraft that was difficult to fly in formation, and hard to land aboard a carrier because a less-than-perfect landing often caused the aircraft to bounce over the arresting wires and into the safety barrier. It was a very stable dive bomber, more so than the Skyraider, and could carry more ordnance. Maintenance problems and the difficulty of landing aboard a carrier caused some pilots to give it the nickname of "Awful Monster".O'Rourke, G. G., CAPT USN. "Of Hosenoses, Stoofs, and Lefthanded Spads". ''United States Naval Institute Proceedings'', July 1968.

Operational history

With the prospect of flying the AD-1 Skyraider and AM-1 in carrier operations, the US Navy assigned the Maulers to Atlantic Fleet squadrons.Swanborough & Bowers 1990, p. 359. Attack Squadron 17A (VA-17A) was the first unit to get the AM-1 and received its 18 aircraft in March and April 1948. It was redesignated VA-174 on 11 August and began carrier qualification trials aboard on 27–28 December and completed them aboard in January 1949 with all assigned pilots completing their day qualifications. During this latter deployment, the squadron participated in the unsuccessful search for a British South American Airways Avro Tudor airliner missing in the Caribbean. The squadron made a brief deployment aboard , one of the largest carriers in the US Navy, in early 1949. The longer flight deck of the carriers made landings easier for the AM-1 pilots and the squadron did not have a single landing accident during its deployment. Upon its return, the unit transferred its aircraft to VA-44 and VA-45, both newly assigned to ''Midway'', and converted to the Skyraider before being disbanded in January 1950. The two squadrons began receiving their aircraft in March 1949 and conducted their carrier qualifications from 2 to 7 May. VA-45 became the only Mauler squadron to complete qualifications without any accidents. They made a short deployment aboard the carrier from 1 to 9 September and began converting back to Skyraiders the following month. Carrier Air Group 8 (CVG-8) was established on 15 September 1948 in response to the

Berlin Blockade The Berlin Blockade (24 June 1948 – 12 May 1949) was one of the first major international crises of the Cold War. During the multinational occupation of post–World War II Germany, the Soviet Union blocked the Western Allies' railway, ro ...

with newly qualified pilots and reservists who volunteered for active duty. VA-84 and VA-85, the air group's attack squadrons, began receiving Maulers in November and the last aircraft was delivered in January 1949. Later that month the air group made a flyover of President

Harry Truman Harry S. Truman (May 8, 1884December 26, 1972) was the 33rd president of the United States, serving from 1945 to 1953. A leader of the Democratic Party, he previously served as the 34th vice president from January to April 1945 under Franklin ...

's Inauguration ceremony. The squadron conducted their qualifications aboard ''Midway'' from 3 to 6 May with ten Maulers crashing into the safety barrier between them. CVG-8 made a two-week cruise aboard ''Midway'' beginning on 27 June along the

East Coast of the United States The East Coast of the United States, also known as the Eastern Seaboard, the Atlantic Coast, and the Atlantic Seaboard, is the coastline along which the Eastern United States meets the North Atlantic Ocean. The eastern seaboard contains the coa ...

, before it was disbanded in November after the peaceful resolution of the Berlin Blockade. AM-1Q VC-4 USS Kearsarge 1949

Many of the AM-1Q electronic-warfare variants were assigned to Composite Squadron 4 (VC-4), based at NAS Atlantic City, and were detached in small groups for each Atlantic Fleet carrier deployment. Little is known about their service and the squadron is last known to have had Maulers assigned on 1 October 1950.Kowalski 1995, p. 60. Although the Skyraider was a third smaller and carried a third less bombload, it proved more reliable in service and easier to fly and land, and Navy pilots preferred it. In 1950 the decision was made to use the Mauler only from shore-based units and later that year all but Naval Reserve units abandoned the type. The aircraft operated with reserve squadrons until 1953.

Variants

;XBTM-1 :Two prototypes built. ;BTM-1/AM-1 :A total of 131 production aircraft, another 651 aircraft were cancelled.Andrade 1979, p. 182 ;AM-1Q :An electronic warfare variant, 18 aircraft built or converted. ;JR2M-1 :Proposed carrier onboard delivery variant of the AM, named Mercury; not built.

Operators

; *

** VA-44, VA-45, VA-84, VA-85, VA-174, VC-4. ** Reserve attack squadrons at NAS Grosse Ile, NAS St. Louis,

NAS Glenview Naval Air Station Glenview or NAS Glenview was an operational U.S. Naval Air Station from 1923 to 1995. Located in Glenview, Illinois, a suburb of Chicago, the air base primarily operated training aircraft as well as seaplanes on nearby Lake Mi ...

NAS Dallas The Grand Prairie Armed Forces Reserve Complex or Grand Prairie AFRC (formerly Naval Air Station Dallas or Hensley Field) is a former United States Navy Naval Air Station located on Mountain Creek Lake in southwest Dallas. The installation was e ...

, NAS Columbus, and

NAS Atlanta General Lucius D. Clay National Guard Center (formerly Naval Air Station Atlanta) is a military facility located south of Marietta, Georgia, United States. It is located immediately south of Dobbins Air Reserve Base and shares its runways. Befor ...

Surviving aircraft

Out of 151 Maulers built, only four complete airframes are known to still exist, with a fifth partial airframe in storage: ;On display ;;AM-1 *22275 – Erickson Aircraft Collection, Madras, Oregon. *122397 –

National Naval Aviation Museum The National Naval Aviation Museum, formerly known as the National Museum of Naval Aviation and the Naval Aviation Museum, is a military and aerospace museum located at Naval Air Station Pensacola, Florida. Founded in 1962 and moved to its cur ...

Pensacola, Florida Pensacola () is the westernmost city in the Florida Panhandle, and the county seat and only incorporated city of Escambia County, Florida, United States. As of the 2020 United States census, the population was 54,312. Pensacola is the principal c ...

. ;In storage or under restoration ;;AM-1 *22260 – under restoration at the Glenn L. Martin Maryland Aviation Museum in

Middle River, Maryland Middle River is an unincorporated community and census-designated place in Baltimore County, Maryland, United States. The population was 33,203 at the 2020 census. A Middle River Train Station first appeared on the 1877 G.M. Hopkins & Co Baltimore ...

. *122403 – in storage at the Planes of Fame in Chino, California."Martin AM-1 Mauler/122403."
''Warbird Directory: Martin Page 9.'' Retrieved: 21 September 2022.

Specifications (AM-1 Mauler)

Notes

Footnotes

Bibliography

* Andrade, John. ''U.S. Military Aircraft Designations and Serials Since 1909''. Midland Counties Publications, 1979. * Andrews, Hal & Walter Boyne. ''The Fable of Able Mable: Flying Fifteen Tons of Midnight Blue Beastie.'' ''Airpower,'' Vol. 4, Issue 4, July 1974. * Breihan, John R., Stan Piet & Roger S. Mason. ''Martin Aircraft, 1909–1960''. Santa Ana, California: Narkiewicz/Thompson, 1995. * Kowalski, Bob. ''Martin AM-1/1-Q Mauler.'' Simi Valley, California: Ginter Books, 1995. . * Swanborough, Gordon & Peter M. Bowers. ''United States Navy Aircraft Since 1911.'' London: Putnam Aeronautical Books, 1990. Third edition. . * Wagner, Ray. ''American Combat Planes of the 20th Century''. Reno, Nevada: Jack Bacon, 2004.

External links

Mauler (AM)AirToAirCombat.Com: Martin AM-1 Mauler"Firepower Under the Wings" ''Popular Science'', April 1949, page 145AM-1 Mauler ACP - 1 March 1947 (Missing Page)
{{Authority control A01M 1940s United States attack aircraft Single-engined tractor aircraft Low-wing aircraft Carrier-based aircraft Aircraft first flown in 1944