The Curtiss XBTC was a prototype single-seat, single-engined

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, s ...

/ dive bomber developed 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 vast majority of the world's countries—including all of the great powers—forming two opposing ...

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 ...

. Four aircraft were ordered, powered by two different engines, but the two aircraft to be fitted with the

Wright R-3350 The Wright R-3350 Duplex-Cyclone is an American twin-row, supercharged, air-cooled, radial aircraft engine with 18 cylinders displacing nearly . Power ranged from 2,200 to over 3,700 hp (1,640 to 2,760 kW), depending on the model. ...

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 ...

were cancelled in late 1942, leaving only the pair using the

Pratt & Whitney R-4360 The Pratt & Whitney R-4360 Wasp Major is an American 28-cylinder four-row radial engine, radial reciprocating engine, piston aircraft engine designed and built during World War II. First run in 1944, at , it is the largest-displacement aviation ...

radial. By this time,

Curtiss Aircraft Curtiss Aeroplane and Motor Company (1909 – 1929) was an American aircraft manufacturer originally founded by Glenn Hammond Curtiss and Augustus Moore Herring in Hammondsport, New York. After significant commercial success in its first decade ...

was overwhelmed with work and the Navy gave the XBTC-2 prototypes a low priority which delayed progress so the first flight did not take place until the beginning of 1945. One aircraft crashed in early 1947 and the other was disposed of later that year.

Design and development

In the 1930s and early 1940s, the Navy divided carrier-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, 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 beacons 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 January 1942 the Navy issued a specification to replace the prewar two-seat, carrier-capable VSB ( Scout Bomber) aircraft with a single-seat aircraft that used the 2,200 hp (1,641 kW) Wright R-3350

. The aircraft was required to be armed with four autocannon and be capable of dive-bombing and

attacks. It was to be provided with an internal

bomb bay The bomb bay or weapons bay on some military aircraft is a compartment to carry bombs, usually in the aircraft's fuselage, with "bomb bay doors" which open at the bottom. The bomb bay doors are opened and the bombs are dropped when over t ...

with space for two bombs or a

Mark 13 torpedo The Mark 13 torpedo was the U.S. Navy's most common aerial torpedo of World War II. It was the first American torpedo to be originally designed for launching from aircraft only. They were also used on PT boats. Design Originating in a 1925 des ...

hung below the fuselage. The range requirement was for with a 1,000-pound bomb or with

drop tank In aviation, a drop tank (external tank, wing tank or belly tank) is used to describe auxiliary fuel tanks externally carried by aircraft. A drop tank is expendable and often capable of being jettisoned. External tanks are commonplace on modern ...

s. Curtiss responded with their Model 96 which was a low-wing

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 retractable

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 ...

with the R-3350 and proposed an alternate powered by the heavier Pratt & Whitney R-4360 radial that would use

contra-rotating propeller Aircraft equipped with contra-rotating propellers, also referred to as CRP, coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston engine, piston or turboprop engine to drive a pair of ...

s to handle the extra horsepower. The Navy agreed to both and issued a letter of intent in late June for two aircraft equipped with the R-3350, the XBTC-1 (BT reflecting its new role), and another pair fitted with the R-4360, the XBTC-2. Due to development and production difficulties with the high-priority SB2C Helldiver dive bomber, along with the

SO3C Seamew The Curtiss SO3C Seamew was developed by the Curtiss-Wright Corporation as a replacement for the SOC Seagull as the United States Navy's standard floatplane scout. Curtiss named the SO3C the ''Seamew'' but in 1941 the US Navy began calling it by ...

and SC Seahawk scout and observation floatplanes, the Navy only awarded a contract for the two XBTC-2 prototypes on 31 December and gave them a low priority. Little documentation about the early development of the XBTC-2 has survived, but photographs of the mockup dated December are available. They show the larger engine installation of the XR-4360-8A and the contra-rotating propellers, but the mockup may have been reworked from the C-1 as it lacks the larger

empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third e ...

that would be necessary to handle the more powerful engine. The prototypes had a fuel capacity of housed in two interconnected

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraf ...

tanks and a pair of interconnected combination wing and fuselage tanks. The two wing hardpoints were plumbed to handle . An additional fuel tank could be fitted in the bomb bay. All control surfaces were skinned with metal and the aircraft was fitted with a set of

dive brake Dive brakes or dive flaps are deployed to slow down an aircraft when in a dive. They often consist of a metal flap that is lowered against the air flow, thus creating drag and reducing dive speed.Crane, Dale: ''Dictionary of Aeronautical Terms, ...

s on the upper and lower surfaces of the inner wing panel as well as slotted flaps along its trailing edge. The outer wing panels were equipped with

leading-edge slat Slats are aerodynamic surfaces on the leading edge of the wing of a fixed-wing aircraft which, when deployed, allow the wing to operate at a higher angle of attack. A higher coefficient of lift is produced as a result of angle of attack and speed, ...

s and had 10° dihedral. XBTC-2SlottedFlap

To improve landing performance the aircraft intended to be fitted with "duplex" (slotted) flaps, but wind-tunnel tests revealed problems with the flaps so two different outer wing panels were developed, both. The so-called "Model A" panel lacked the flaps and was lengthened by . Its leading edge was perpendicular to the fuselage centerline and its trailing edge followed the taper of the inner wing panel. It was fitted with an aileron that started at the tip and extended inwards for about 3/4s of the panel's span; the remaining space was used by ordinary slotted flaps. It was also equipped with another pair of dive brakes. The "Model B" panel reversed the relationship of the leading and trailing edges. Its aileron occupied the entire trailing edge and the "duplex" flaps were positioned on the underside of the wing, just ahead of the aileron. In use, they were lowered to create space for air to reach the underside of the ailerons. The armament of the XBTC-2s consisted of four 20 mm autocannon, each with 200 rounds. The bomb bay contained a single shackle that could handle ordnance up 1,600 pounds in weight. In a dive, the bomb was swung clear of the propeller on a H-shaped trapeze prior to release. A torpedo (such as the

Mark 13 Mark 13 is the thirteenth chapter of the Gospel of Mark in the New Testament of the Christian Bible. It contains Jesus' predictions of the destruction of the Temple in Jerusalem and disaster for Judea, as well as his eschatological discourse.Hall ...

) could be mounted on the bomb bay doors, although nothing could be dropped from the bomb bay in that case. The wing hardpoints were stressed to carry weapons weighing up to 1,000 pounds. Curtiss XBTC-2 after a crash c1946

Development and construction of the two prototypes was delayed by the low priority given to the program by the Navy, so the aircraft did not make its first flight until 20 January 1945. It was fitted with a pre-production XR-4360-8A engine and the "Model A" wing. Although the second aircraft equipped with a production R-4360-14 engine and the "Model B" wing, both prototypes were initially fitted with Curtiss Electric propellers, but they were replaced by Aeroproducts AD7562 propellers sometime after a landing accident with the first prototype on 3 March. The aircraft was repaired and was later fitted with a "Model B" wing. They were delivered to the Naval Air Test Center at

Naval Air Station Patuxent River 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 S ...

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

, on 30 July 1946. The second prototype crashed during stall testing when its engine failed on 17 March 1947. The surviving prototype was transferred to the Naval Air Material Unit in August for disposal.Kowalski, pp. 18, 36–39; Wagner, p. 441 The

United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...

assigned the designation A-40 to a proposed 'de-navalized' version of the XBTC; however, it later decided not to acquire any further single-engine attack aircraft and the project was cancelled.Wagner, p. 441

Variants

* Curtiss XBTC-1:

Wright R-3350 Duplex-Cyclone The Wright R-3350 Duplex-Cyclone is an American twin-row, supercharged, air-cooled, radial aircraft engine with 18 cylinders displacing nearly . Power ranged from 2,200 to over 3,700 hp (1,640 to 2,760 kW), depending on the model. ...

engine * Curtiss XBTC-2:

Pratt & Whitney R-4360 Wasp Major The Pratt & Whitney R-4360 Wasp Major is an American 28-cylinder four-row radial piston aircraft engine designed and built during World War II. First run in 1944, at , it is the largest-displacement aviation piston engine to be mass-produced in ...

engine

Operators

; *

Specifications (XBTC-2)

Curtiss XBTC-2 BuAer 3 side drawing 1944

References

Notes

Bibliography

*Andrews, Hal
"XBTC-2"
''Naval Aviation News''. November–December 1987. pp. 16–17. * Bowers, Peter M. ''Curtiss Aircraft 1907–1947''. London: Putnam, 1979. . * Breihan, John R., Stan Piet & Roger S. Mason. ''Martin Aircraft, 1909–1960''. Santa Ana, California: Narkiewicz/Thompson, 1995. *Kowalski, Bob. ''Curtiss XBTC-2 "Eggbeater"'' (Naval Fighters, Number 77). Simi Valley, California: Steve Ginter, 2007 *Wagner, Ray. ''American Combat Airplanes of the 20th Century: A Comprehensive Reference''. Reno, Nevada: Jack Bacon & Co., 2004.