Aviation Naval Warfare Land Systems Small Arms By Flag By Year By Tag

Martin XB-51

1949 COLD WAR X-PLANE

Martin XB-51 History

Developed as a depth bomber and ground attack platform for the United States Army Air Forces (USAAF) at the time, the Martin XB-51 proved a failure and only a few prototypes were produced. The first flight was recorded on October 28, 1949, and the program ran until 1952, when it was officially cancelled, then officially retired in March 1956 at a cost of $12. $6 million.

Both prototypes were eventually lost in accidents, ending any idea they would eventually be displayed as museums. The renamed US Air Force (from 1947) eventually chose the British electric Canberra bomber to replace it.

The XB-51 was designed to meet USAF requirements for light bombardment/ground attack missions by replacing its aging Douglas A-26 Intruder line. Martin engineers brought a unique turbojet design, in which the aircraft used three engines - a main pair along the nacelle away from the lower forward fuselage and a third engine sunk into the tail.

The flat sides of the hull also have a unique look. The surface is all silver, consistent with the American aircraft of the time. The main wing elements are centrally mounted and swept back at a 35-degree angle for aerodynamic efficiency.

Each element shows a variable incidence of takeoff and landing maneuvers, and has built-in anti-icing. Dive brakes were added to control the glide during combat diving maneuvers designed for the aircraft. The tail consists of a "T-shaped" tail that uses a vertical tail as a support for an elevated horizontal aircraft. The third engine is drawn in from the fuselage spine at the bottom of the tail system and expelled through a port in the rear.

The cockpit is well-maintained in design and is located behind the downwardly sloping nose cone assembly to provide the pilot with the necessary vision outside the cockpit. The crew consists of the chief pilot and a systems officer, and the cockpit features a pressurized air-conditioned cockpit with ejection seats and a bulletproof windshield. However, only the pilot sits under the designated canopy, as system officials hide in concealed locations nearby. The landing gear was in a "bike" arrangement, using two twin-tire main landing gear legs in tandem and small single-wheel support legs on the wingtips - the latter used to control lateral stability. At rest, the aircraft has a distinct "nose up" appearance.

The release of a tow chute at the stern aids in landing.

The XB-51 is powered by 3 General Electric J47-GE-13 turbojets, each rated at 5,200 pounds of thrust. This includes a water-alcohol-grade thrust to support short/fast takeoff maneuvers beyond the normal thrust capabilities of the turbojet. In addition, 4 x 14-second Rocket Assisted Takeoff ("RATO") rocket pods can be mounted aft of the fuselage, producing an additional 954 pounds of thrust per launch tube. The engines are armored against ground artillery (FlaK type), and their combined power output allows the airframe to reach a top speed of 645 mph and a cruising speed of about 530 mph.

The ferry has a range of 1,600 miles and operates a service capped at 40,500 feet (thus pressurizing the crew's cockpit).

Dimensions include a wingspan of 53 feet, a length of 85 feet, and a height of 17.3 feet. Empty weight is listed as 29,590 pounds, and maximum takeoff weight is 62,560 pounds.

Proposed armament for the XB-51 family consists of 8 x 20mm guns and a total of 1,280 x 20mm projectiles. All guns are mounted in the nose assembly for strafing on land or sea targets. An internal bomb bay is embedded in the hull with a rotating delivery system that can carry up to 10,400 pounds of internal storage. This would include conventionally dropped bombs or 8 x 5 inch high velocity rockets (HVAR). The aircraft's targeting system includes an A-1-B artillery missile sight with radar ranging capability.

All gun movements are recorded, with an onboard camera and a rear camera recording the ground for damage assessment during strafing/bombing runs. Another camera was installed for high altitude attack work or general reconnaissance. The XB-51 uses SHORAN (Short Range Navigation). ) has proven its bomb system in the Korean War (1950-1953) with the light bomber Douglas A-26/B-26 Raider and the heavy bomber Boeing B-29 Superfortress.

The SHORAN system combined the AN/APN-3 radar and K-1A bomb computer with a pair of AN/CPN-2/2A ground stations to improve bombing efficiency during World War II (1939-1945).

The XB-51 prototypes have serial numbers 46-685 and 46-686. Its original attack-oriented approach established the lesser-known short designation "XA-45" before the introduction of the bomber-oriented classification yielding the designation "XB-51".

The original USAAF request was submitted by Martin as well as Avro Canada (CF-100) and English Electric (Canberra). While the XB-51 proposal was favored over the two competing types for its inherent speed and maneuverability, it ultimately lost out to Canberra, England, which was highly sought after due to its superior range. The Canberra was procured by the U.S.

Air Force, now renamed the "B-57," and ironically the Glen L. Martin factory produced 250 of them.

Despite the setback of the XB-51 program, the prototype continued flight testing after its official, potential U.S. Air Force operation ended. Two prototypes were subsequently lost in separate crashesthe second was lost during an exercise in May 1952, and the first was lost on a flight to Elgin Air Force Base in March 1956.

This ended the brief use of the Martin XB-51.