Martin JRM-3 Mars, Bu. No. 76822, Marshall Mars. (U.S. Navy)
19 May 1949: Martin JRM-3 Mars, Marshall Mars, United States Navy Bureau of Aeronautics serial number (Bu. No.) 76822 flew from the Alameda Naval Air Station on the east shore of San Francisco Bay, to San Diego Bay, a distance of approximately 450 miles (725 kilometers). On board, in addition to the flight crew of 7, were 301 passengers.
Martin JRM-3 Marshall Mars with its passengers. (NOAA)
The Associated Press wire service reported the story:
NAVY’S BIG FLYING BOAT MARSHALL MARS CARRIES 301 PERSONS
SAN FRANCISCO, May 19—(AP)—The Navy’s big flying boat Marshall Mars carried a record load of 301 passengers—plus seven crewmen—on a flight to San Diego today.
It had never carried more than 269 passengers before.
The 1:52 p.m. takeoff, from the naval air station at Alameda, across the bay, was uneventful.
Today’s passengers are personnel of Air Group 5, Alameda Naval Air Station, who are being transferred to San Diego. Mattresses on the floor were provided for men unable to find seats.
Four Martin JRM-3 Mars flying boats in formation. In the foreground is Philippine Mars, Bu. No. 76820. The second airplane is Marianas Mars, Bu. No. 76821. (U.S. Navy)
The Martin JRM Mars was a large four-engine flying boat transport built by the Glenn L. Martin Company for the U. S. Navy. Only five were built, four designated JRM-1, with the last one being a JRM-2. Each airplane was given an individual name derived from the names of island chains in the Pacific Ocean: Marianas Mars, Hawaii Mars, Philippine Mars, Marshall Mars and Caroline Mars. These airplanes were used to transport personnel and cargo between the West Coast of the United States and the Hawaiian Islands. All were upgraded to JRM-3.
The Martin JRM-3 Mars had a normal crew of 4, with accommodations for a relief crew. It was designed to carry 133 combat troops or 32,000 pounds (14,515 kilograms) of cargo. It was 120 feet, 3 inches (36.652 meters) long with a wingspan of 200 feet (60.960 meters) and height of 38 feet, 5 inches (11.709 meters). The flying boat had an empty weight of 80,701 pounds (36,605.4 kilograms). The maximum takeoff weight (MTOW) was 165,000 pounds (74,842.7 kilograms).
A NASA publication states, “A zero-lift drag coefficient of 0.0233 and a maximum lift-drag ratio of 16.4 made the JRM the most aerodynamically efficient of any of of the flying boats. . . .”
The Martin Mars was powered by four air-cooled, supercharged, direct-fuel-injected, 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division R-3350-24WA (Cyclone 18 825C18BD1) (also known as the Duplex-Cyclone), a two-row 18-cylinder radial engines with a compression ratio of 6.70:1 and water/alcohol injection. This engine has a normal power rating of 2,000 horsepower at 2,400 r.p.m at 5,500 feet (1,676 meters) and 1,800 horsepower at 2,400 r.p.m. at 15,000 feet (4,572 meters). The engine’s takeoff power rating is 2,500 horsepower at 2,900 r.p.m. 100/130 octane aviation gasoline was required. The engines drove four-bladed 16 foot, 8 inch (5.080 meter) Curtiss Electric variable-pitch propellers through a 0.375:1 gear reduction. (After modification to the JRM-3, the propellers on the inboard engines were reversible.) The R-3350-24WA is 6 feet, 8.58 inches (2.047 meters) long, and 4 feet, 6.13 inches (1.375 meters) in diameter. Its dry weight is 2,822 pounds (1,280 kilograms).
The JRM-3 had a cruise speed of 135 knots (155 miles per hour/250 kilometers per hour) and a maximum speed of 211 knots (243 miles per hour/391 kilometers per hour) at 15,600 feet (4,755 meters). The service ceiling was 19,700 feet (6,005 meters) and its range was 3,790 nautical miles (4,361 miles per hour/7,019 kilometers) at 135 knots.
On 5 April 1950, Marshall Mars had an engine fire and made an emergency landing off Diamond Head, Hawaii. The crew was rescued but the airplane exploded and sank. The wreck was discovered on the sea floor in August 2004.
The remaining airplanes were later converted to fire fighting airplanes in Canada. Only two remain.
Martin JRM-3 Mars, Bu. No. 76822, Marshall Mars, burning off Diamond Head, Oahu, Territory of the Hawaiian Islands, 5 April 1950. (U.S. Navy)
Viking 1 launch (Chicago Tribune)Viking 1 launch (AP Wirephoto/Baltimore Sun)
3 May 1949: at 9:14 a.m., Mountain Daylight Saving Time (15:14 UTC), the Viking 1 rocket was launched from the White Sands Proving Grounds in southern New Mexico. The rocket carried a 460 pound (210 kilogram) instrumentation payload.
This was the first launch of a U.S.-designed and -built rocket capable of carrying a payload to space.¹
Viking 1 surrounded by the service gantry. The rocket is angled to the north by 3°. (Drew Ex Machina)
Although the planned engine run time was 65 seconds, Viking 1’s engine shut down after 54.5 seconds. At that time, the rocket had reached a speed of 2,350 miles per hour (3,780 kilometers per hour). After the engine shut down, Viking 1 continued to climb on a ballistic trajectory to an altitude of 50 miles (81 kilometers). As it fell back to Earth, 291 seconds after launch, the rocket broke up and was scattered across many miles of the Proving Grounds.
Viking 1 was a single-stage liquid-fueled rocket. It was built by the Glenn L. Martin Company for the Naval Research Laboratory. It was constructed primarily of aluminum. The skin was rolled into a cylinder and welded. It was 47 feet, 7.5 inches (14.516 meters) long, 2 feet, 8 inches (0.813 meters) in diameter, with a fin span of 9 feet, 2.5 inches (2.807 meters). Each fin had an area of 15 square feet (1.39 square meters). The rocket had a gross weight of 10,824 pounds (4,910 kilograms).
A Reaction Motors XLR10-RM-2 rocket engine. (Reddit)
Viking 1 was powered by a Reaction Motors Inc. XLR10-RM-2 engine. It’s propellant was a mixture of ethanol and water, mixed at a ratio of 95:5. The oxidizer was liquid oxygen. The engine produced 20,800 pounds of thrust (92.523 kilonewtons) at Sea Level, and 24,800 pounds (110.316 kilonewtons) in vacuum. Fuel was fed to the engine by a turbopump driven by high-pressure hydrogen peroxide steam. Turning at 10,000 r.p.m., the turbopump provided propellant at a rate of 110 pounds (50 kilograms) per second.
Static test firing of the Viking 1 rocket engine. (Drew Ex Machina)
The engine was mounted on gymbals which were controlled by gyroscopes. By rapidly angling the engine exhaust away from the rocket’s centerline, the engine was able to stabilize the rocket. A British Pathé news film (available on YouTube) showing the launch of Viking 2 illustrates this:
¹ “Space” is defined as being above the von Kármán Line, the boundary between the Earth’s atmosphrere and outer space, at an altitude of 100 kilometers (62.14 miles)
Pan American Airways’ Martin M-130, China Clipper, at Macau, 1937.
28 April 1937: The first transpacific flight by a commercial passenger airliner is completed when Pan American Airways’ Martin M-130, China Clipper, arrived at Hong Kong. The flight had departed San Francisco Bay, California, on 21 April with 7 revenue passengers and then proceeded across the Pacific Ocean by way of Hawaii, Midway Island, Wake Island, Guam, Manila, Macau, and finally Hong Kong. The Reuters news agency briefly reported the event:
AIR LINK AROUND WORLD FORGED.
China Clipper Lands At Hong Kong.
Hong Kong, April 28.
The Pan-American Airways flying boat China Clipper landed at 11:55 this morning from Manila and Macao. This links the Pan-American and Imperial Airways, completing the commercial air link round the world. —Reuter.
—The Straits Times, 28 April 1937, Page 1, Column 4.
Pan American Airways’ China Clipper, a Martin M-130, NC14716, over Oakland, California. (Clyde Herwood Sunderland/Library of Congress 94509042)
The Oakland Tribune reported:
AIR CLIPPER SPANS SEAS TO HONGKONG
U.S. MAIL TO CHINA LANDED IN SIX DAYS
Plane Crew Feted at End Of Historic Hop From U.S. Via Philippines
HONGKONG, April 28.—(AP)—A 30-year dream of ’round-the-world air service became reality today with the arrival of the Hongkong Clipper from Manila on the first regular flight between the two cities.
The clipper, bridging the last 700-mile gap in the America-Asia service, placed the final link in an airplane chain whereby it is possible to encircle the world in less than a month, using scheduled commercial planes.
The craft brought 2500 pounds of American cargo, including 100,000 letters and newspapers from the United States only six days old. The papers left Alameda, Calif., last Thursday aboard China Clipper, being transferred to the Hongkong Clipper at Manila. ¹
A large crowd welcomed the clipper at Kaitak Airport. Included were Acting Governor N. L. Smith and representatives of all of the colony’s government and commercial activities.
The clippers’ pilot, A. E. Laporte, and crew were escorted to a dais at the hangar, where the acting governor gave a speech of welcome.
The plane, on its return flight on Thursday, is expected to carry 2500 pounds of cargo, including 40,000 letters.
At a reception for the fliers, the acting governor said:
“We are celebrating the welding of the last link in world air communication. The lessening of the physical gaps is the surest way of ending misunderstandings which have occurred between nations in the past.
“Hongkong offers congratulations, welcomes this American transpacific air service and hopes it will be another bond in the chain of goodwill.”
Laporte said the Manila-Hongkong flight was “uneventful,” despite poor weather conditions necessitating intermittent blind flying.
The China Clipper, NC14716, was the first of three Martin M-130 four-engine flying boats built for Pan American Airways and was used to inaugurate the first commercial transpacific air service from San Francisco to Manila in November, 1935. Built at a cost of $417,000 by the Glenn L. Martin Company in Baltimore, Maryland, it first flew on 20 December 1934, and was delivered to Pan Am on October 9, 1935.
The airplane was operated by a flight crew of 6 to 9, depending on the length of the flight, plus cabin staff, and could carry 18 passengers on overnight flights or a maximum 36 passengers.
Martin M-130 China Clipper, NC14716, at Honolulu, Oahu, Hawaiian Islands. (Unattributed)
The Martin M-130 was 90 feet, 10.5 inches (27.699 meters) long with a wingspan of 130 feet, 0 inches (39.624 meters). It was 24 feet, 7 inches (7.493 meters) high. Its maximum takeoff weight was 52,252 pounds (23,701 kilograms).
The flying boat was powered by four air-cooled, supercharged, 1,829.389-cubic-inch displacement (29.978 liters) Pratt & Whitney Twin Wasp S2A5-G engines. These were two-row, 14-cylinder radial engines with a compression ratio of 6.7:1. The S2A5-G was rated at 830 horsepower at 2,400 r.p.m., and 950 horsepower at 2,550 r.p.m. for takeoff, burning 87-octane gasoline. They drove three-bladed Hamilton Standard Hydromatic constant-speed propellers through a 3:2 gear reduction. The engine was 3 feet, 11.88 inches (1.216 meters) in diameter and 4 feet, 8.75 inches (1.441 meters) long. It weighed 1,235 pounds (560 kilograms).
The airplane had a maximum speed of 180 miles per hour (290 kilometers per hour), and a cruise speed of 130 miles per hour (209 kilometers per hour). The service ceiling was 10,000 feet (3,048 meters) and its range was 3,200 miles (5,150 kilometers).
Martin M-130, NC14716, China Clipper, moored at some distant exotic locale. (Unattributed)
¹ There may be confusion as to which airplane was flown from Manila to Hong Kong. Most newspapers identified it as China Clipper, while the Oakland Tribune called it Hongkong Clipper.
Pan American’s Hong Kong Clipper was a Sikorsky S-42, NC823M, which had entered service in December 1934. Many newspapers dated 28 April 1937 showed a photograph of NC832M arriving at Auckland, New Zealand, after a four-day, 7,000-mile survey flight from the United States.
Entering service in 1934, the airline had originally named the NC823M West Indies Clipper. This was changed to Pan American Clipper, and later, Hong Kong Clipper. The airplane crashed on takeoff and sank near Antilla, Cuba, 7 August 1944.
Pan American Airways System’s Sikorsky S-42, NC832M, over San Francisco Bay, 1935. (NASM SI-90-3001)
Martin JRM-3 Mars Bu. No. 76822, Marshall Mars, burning off Diamond Head, Oahu, Hawaiian Islands, 5 April 1950. (U.S. Navy)
5 April 1950: While on a test flight following an engine change, a United States Navy Martin JRM-3 Mars seaplane, Marshall Mars, Bu. No. 76822, suffered an engine fire (inboard, left wing) and made an emergency landing at Ke’ehi Lagoon, off Diamond Head, Hawaii. The airplane’s crew was rescued but the airplane exploded and sank.
The wreck was discovered on the sea floor in August 2004 at a depth of approximately 1,400 feet (427 meters).
The Martin JRM Mars was a large four-engine flying boat transport built by the Glenn L. Martin Company for the U. S. Navy. originally designed as a patrol bomber, the prototype XPB2M-1 Mars made its first flight on 3 July 1942, Only five transport variants were built, four designated JRM-1, with the last one being a JRM-2. Each airplane was given an individual name derived from the names of island chains in the Pacific Ocean: Marianas Mars, Hawaii Mars, Philippine Mars, Marshall Mars and Caroline Mars. These airplanes were used to transport personnel and cargo between the West Coast of the United States and the Hawaiian Islands. All were upgraded to JRM-3.
Four Martin JRM-3 Mars flying boats in formation. (U.S. Navy)
The Martin JRM-2 Mars had a normal crew of 4, with accommodations for a relief crew. It was designed to carry 138 combat troops or 34,000 pounds (15,422 kilograms) of cargo. It was 120 feet, 3 inches (36.652 meters) long with a wingspan of 200 feet, 0 inches (60.960 meters) and height of 43 feet, 8 inches (13.310 meters), with beaching gear. The wing area was 3,686 square feet (342.4 square meters). The flying boat had an empty weight of 80,701 pounds (36,605 kilograms) and a maximum takeoff weight (MTOW) 0f 165,000 pounds (74,843 kilograms).
Martin JRM-2 Mars three-view illustration with dimensions. (U.S. Navy)
A NASA publication states, “A zero-lift drag coefficient of 0.0233 and a maximum lift-drag ratio of 16.4 made the JRM the most aerodynamically efficient of any of the flying boats. . . .”
Martin JRM-3 Mars, Bu.No. 76822, Marshall Mars. (U.S. Navy)
The Martin Mars was powered by four air-cooled, supercharged, direct-fuel-injected, 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division R-3350-24WA (Cyclone 18 825C18BD1) (also known as the Duplex-Cyclone), a two-row 18-cylinder radial engines with a compression ratio of 6.70:1 and water/alcohol injection. This engine has a normal power rating of 2,000 horsepower at 2,400 r.p.m at 5,500 feet (1,676 meters) and 1,800 horsepower at 2,400 r.p.m. at 15,000 feet (4,572 meters). The engine’s takeoff power rating is 2,500 horsepower at 2,900 r.p.m. 100/130 octane aviation gasoline was required. The engines drove four-bladed 16 foot, 8 inch (5.080 meter) Curtiss Electric variable-pitch propellers through a 0.4375:1 gear reduction. (After modification to the JRM-3, the propellers on the inboard engines were reversible.) The R-3350-24WA is 6 feet, 8.58 inches (2.047 meters) long, and 4 feet, 6.13 inches (1.375 meters) in diameter. Its dry weight is 2,822 pounds (1,280 kilograms).
The JRM-3 had a cruise speed of 165 knots (190 miles per hour/306 kilometers per hour) and a maximum speed of 211 knots (243 miles per hour/391 kilometers per hour) at 15,600 feet (4,755 meters). The service ceiling was 19,700 feet (6,005 meters) and its range was 3,790 nautical miles (4,361 statute miles/7,019 kilometers).
A U.S. Navy Martin JRM Mars. (Glenn L. Martin Co.)
Martin XB-51 46-685, the number one prototype, on takeoff. (Lockheed Martin)
25 March 1956: At approximately 10:50 a.m., the first of two prototype Martin XB-51 three-engine attack bombers, serial number 46-685, crashed on takeoff from Runway 22 at El Paso International Airport (ELP). The pilot, Major James Otto Rudolph, United States Air Force, survived the crash although he was seriously burned. Staff Sergeant Wilbur Robert Savage, 28, engineer, was killed. Major Rudolph died of injuries 16 April 1956.
Pieces of wreckage were marked “Gilbert XF-120” which had been painted on the airplane for the filming of the William Holden, Lloyd Nolan movie, “Toward The Unknown.” (Toluca Productions, 1956). The second prototype, 46-686, had previously crashed at Edwards AFB.
A newspaper article from the El Paso Times is quoted below [I have corrected some typographical errors]:
03/26/1956
Bill Feather El Paso Times
A sleek jet bomber, carrying a full load of fuel, crashed while attempting a take-off at International Airport Sunday morning, killing the flight engineer and seriously injuring the pilot.
The XB-51, the only one of its type in existence, smashed through the fence at the end of the southwest runway and then began to disintegrate, spreading wreckage along a 250-yard trail.
Only the tail section of the three-engine bomber was left intact.
Name of the dead man, a 28-year-old staff sergeant was withheld pending notification of next of kin.
Flying the aircraft was Maj. James O. Rudolph, 36, one of the top test pilots in the Air Force.
He suffered severe burns and was taken Sunday afternoon in an emergency flight to Brooke Army Hospital in San Antonio.
The XB-51, based at Edwards Air Force Base in Muroc, Calif., was being flown to Eglin Air Force Base, Florida, where it was to be used in the filming of a Warner Brothers movie, “Toward the Unknown.”
Identification of the aircraft was confused for a short time after the crash.
A piece of wreckage with the notation “Gilbert XF-120” was found nearby.
HAD REFUELED
Air Force spokesmen explained that the XF designation had been painted on the plane for use in the movie.
The airplane had been refueled at International Airport and started its takeoff at 10:30 a.m.
Witnesses said the plane got about three feet above the ground and suddenly settled. The tail dragged first and then the rest of the airplane settled, running at high speed.
It ripped through a barbed wire fence at the end of the runway, raced across Airport Road and then began to go to pieces.
After crashing, it burned and several explosions threatened firemen, rescuers and spectators who crowded around the flaming aircraft.
First person to the scene of the crash was Eddie C. Wilkerson, 1106 Del Monte Drive, tennis coach at Austin High School.
“I was just turning into the road to the airport when the plane was taking off. I don’t believe it ever got airborne.
“I looked back and saw a big ball of smoke, so I just wheeled my car around.”
Wilkerson said that when he arrived, the major was lying on the ground about 15 feet from the burning wreckage.
“His clothes were burning so I started tearing them off.”
Other witnesses to the crash arrived and helped Wilkerson move the major to a safer place, away from the intense heat of the flaming aircraft.
Capt. John D. Chandler, a doctor at the Biggs Hospital, was at the airport when the crash occurred and he was one of the first persons at the scene. He administered aid to the injured man until an ambulance arrived. Later Capt. Chandler flew to San Antonio with Maj. Rudolph.
A fire truck from International Airport was rushed to the scene almost as soon as the plane stopped its forward motion.
Sunday drivers were attracted to the scene by the tower of smoke and the heavy traffic delayed the arrival of fire trucks from Biggs Air Force Base.
The plane was one of two XB-51s built by Martin Aircraft Co. and was completed in 1953.
The first one crashed at Muroc, Calif., in 1952.
Air Force spokesmen said the aircraft was comparable to the B-47, which was accepted instead of the XB-51 for use in the Air Force.
Its three jet engines one in each wing and on in the fuselage, were capable of driving the craft at tremendous speeds. The aircraft had broken the sound barrier, spokesmen said.
Its sleek lines gave it the appearance of a fighter rather than a medium bomber.
Normally, the airplane carried a crew of three.
Recently it had been used in assisting the Army in missile and anti-aircraft development at Aberdeen Proving Ground, Md.
A board of officers was investigation the crash and two Air Force colonels arrived at Biggs Air Force Base from Muroc Sunday afternoon.
Military police from Ft. Bliss and Air Police patrolled the area about the crash Sunday afternoon, keeping away the curious.
James Otto Rudolph was born at Marion, Ohio, 8 February 1920, the first of two children of of Frank Otto Rudolph, a German immigrant who was employed as a secretary for the YMCA, and Helen Claire Shafer Rudolph.
Following two years of college, Rudolph enlisted as an Aviation Cadet, U.S. Army Air Corps, at Detroit, Michigan, 17 March 1941. He was 6 feet, 1inch (1.854 meters) tall and weighed 175 pounds (79.4 kilograms). He was commissioned as a Second Lieutenant, Air Reserve, 31 October 1941,and was promoted to First Lieutenant, Army of the United States (Air Corps), 5 August 1942. He was again promoted, to Captain, 15 June 1943. Following the end of World War II, Rudolph was promoted to the rank of Major, 19 September 1946. He remained in the Air Force, but with military needs shrinking, he reverted to the rank of First Lieutenant, with date of rank, 7 December 1944.
James Rudolph married Clara D. in 194–
Major Rudolph graduated from the U.S. Air Force Experimental Flight Test Pilot School, Class 54-A, 2 July 1954. As a test pilot at Edwards Air Force Base, Rudolph was a project pilot in the FICON program in which Republic RF-84K Thunderflash reconnaissance planes were carried by modified Convair RB-36D bombers.
During his military career, Major Rudolph had been awarded the Air Medal with three oak leaf clusters (four awards).
After the crash on 25 March 1956, Major Rudolph was taken to Brooke Army Hospital, Fort Sam Houston, Texas, suffering from 2nd and 3rd degree burns over 38% of his body. He contracted septicemia and died there, 16 April 1956. He is buried at Arlington National Cemetery.
Wilbur Robert Savage was born 19 July 1927 at Dawsonville, Georgia. He was the son of Newton McKinley Savage and May Belle Carney Savage. He married to Ida Pedroza Aceves in 1948. They would have three children.
Staff Sergeant Savage’s remains were interred at Mountain View Cemetery, San Bernardino, California.
The first Martin XB-51, 46-585, in flight. (U.S. Air Force)
The Glenn L. Martin Co. XB-51 was a prototype jet-powered ground attack bomber. It was an unusual design for its time. The airplane had mid-mounted, variable-incidence swept wing, a T-tail and tandem landing gear with a configuration similar to that used on the Boeing B-47 Stratojet (and which had been tested using a Martin B-26 Marauder medium bomber.)
The XB-51 was operated by a pilot in a single-place cockpit with a bubble canopy, and a navigator station inside the fuselage, below and behind the pilot. The prototype was 85 feet, 1 inch (25.933 meters) long with a wingspan of 53 feet, 1 inch (16.180 meters) and overall height of 17 feet, 4 inches (5.283 meters). The total wing area was 548.0 square feet (50.9 square meters). The airplane had an empty weight of 30,906 pounds (14,019 kilograms) and a maximum overload takeoff weight of 62,452 pounds (28,328 kilograms).
Martin XB-51. (Glenn L. Martin Company)
The wings of the XB-51 were swept aft to 35° and had 6° anhedral. The wings’ angle of incidence (the relation of the chord to the fuselage longitudinal axis) could be adjusted to increase lift for takeoff and landing. They had 2° negative twist and were equipped with leading edge slats for improved low speed performance. Instead of ailerons, the XB-51 used spoilers.
Lloyd Nolan (“General Bill Banner”) and William Holden (“Major Lincoln Bond”) with the “Gilbert XF-120” in the 1956 Hollywood movie, “Toward the Unknown.” (Toluca Productions via Turner Classic Movies)
Power was supplied by three General Electric J47-GE-13 turbojet engines, with two located in nacelles outboard of the forward fuselage on 45° pylons, and a third installed in the tail with its intake on top of the fuselage. The J47-GE-13 was an axial-flow turbojet with a 12-stage compressor and single stage turbine. It had a normal power rating of 4,320 pounds of thrust (19.216 kilonewtons) at 7,370 r.p.m.; military power, 5,200 pounds (23.131 kilonewtons) at 7,950 r.p.m. (30-minute limit); and maximum power rating of 6,000 pounds(26.689 kilonewtons) at 7,950 r.p.m., with water/alcohol injection (5-minute limit). The engine was 12 feet, 0.0 inches (3.658 meters) long, 3 feet, 3.0 inches (0.991 meters) in diameter and weighed 2,525 pounds (1,145 kilograms). A Rocket Assisted Takeoff (RATO) system was also installed.
The XB-51 had a maximum speed of 560 knots (644 miles per hour/1,037 kilometers per hour) at Sea Level—0.85 Mach. The service ceiling was 39,400 feet (12,009 meters) and the maximum ferry range was 1,255 nautical miles (1,444 statute miles/2,324 kilometers).
Armament was planned for a maximum bomb load of 10,400 pounds (4,717 kilograms) carried internally in a rotary bomb bay, and eight M39 20 mm revolving autocannon mounted in the nose with 160 rounds of ammunition per gun. 5-inch High Velocity Aerial Rockets (HVAR) could be carried under the wings or in the bomb bay.
Martin XB-51 46-685 during engine start and ground run-up. (U.S. Air Force)
