TSGT Samuel O. Turner, U.S. Air Force, rests his hand on one of four air-cooled Browning AN-M3 .50-caliber aircraft machine guns of a B-52 tail turret. (“Bulldog Bulletin, Fall 1985”)
18 December 1972: On the first night of Operation Linebacker II, Staff Sergeant Samuel Olin Turner, United States Air Force, the gunner aboard Boeing B-52D-35-BW Stratofortress 56-676 (call sign “Brown 3”), saw a supersonic Mikoyan-Gurevich MiG 21 interceptor approaching the bomber from below and behind, with a second interceptor following at a distance.
As the Mach 2 fighter made a firing pass, Turner directed the four Browning AN-M3 .50-caliber machine guns of the bomber’s tail turret at the enemy fighter and opened fire. In a single 6–8 second burst, he expended 694 rounds of ammunition. He saw “a gigantic explosion to the rear of the aircraft.”
Master Sergeant Louis E. LeBlanc, the gunner on another B-52, “Brown 2,” had also seen the MiG 21 and confirmed Turner’s kill.
A Mikoyan-Gurevich MiG-21 interceptor at the National Museum of the United States Air Force, in the markings of the VPAF. (U.S. Air Force)
Staff Sergeant Turner was the first B-52 gunner to be officially credited with shooting down an enemy fighter, and the first aerial gunner to shoot down an enemy aircraft since the Korean War. He was awarded the Silver Star.
The citation reads,
Silver Star
Staff Sergent Samuel O. Turner distinguished himself by gallantry in connections with military operations against an opposing armed force as a B-52 Fire Control Operator near Hanoi, North Vietnam, on 18 December 1972. On this mission, Sergeant Turner’s aircraft was attacked by numerous enemy fighters. During these attacks he skillfully operated his gunnery radar equipment to train his guns on the attackers and destroyed one of them. By his courage in the face of hazardous combat conditions and outstanding professional skill, he successfully defended his aircraft and its crew and enabled it to complete its mission and return safely to base. By his gallantry and devotion to duty, Sergeant Turner has reflected great credit upon himself and to the United States Air Force.
Staff Sergeant Samuel O. Turner is awarded the Silver Star by General John C. Meyer, Commander in Chief, Strategic Air Command, for his actions in combat over Hanoi during Linebacker II. (U.S. Air Force)The tail gun turret of Boeing B-52D Stratofortress 56-676. (U.S. Air Force)
Samuel Olin Turner was born at Atlanta, Georgia, 15 August 1942. He was the son of William Edgar Turner and Beatrice Honnicutt Turner. Sam Turner attended Russell High School at East Point, Georgia, then studied at David Lipscomb College, Nashville, Tennessee.
Turner enlisted in the United States Air Force, 13 January 1970, and was trained as a gunner on Boeing B-52s. He served in Southeast Asia for two years. In 1977, Technical Sergeant Turner transitioned to the B-52H Stratofortress, which was equipped with a remotely-operated M61A1 20 mm six-barreled rotary cannon.
The gunner’s position in the tail of a Boeing B-52D Stratofortress. (MSGT L. Emmett Lewis, U.S. Air Force/U.S. National Archives)
Senior Master Sergeant Samuel O. Turner was released from the U.S. Air Force 31 January 1982. In addition to the Silver Star, during his military career Turner had been awarded the Distinguished Flying Cross and a number of Air Medals. He died at Stockbridge, Georgia, 9 April 1985, at the age of 42 years.
The Samuel O. Turner Airman Leadership School at Ellsworth Air Force Base, near Rapid City, South Dakota, is named in his honor.
56-676 was the last Boeing B-52D Stratofortress in service. It is on display at Fairchild Air Force Base, Spokane, Washington.
A Boeing B-52D Stratofortress of the 307th Strategic Wing over Vietnam during Operation Linebacker II, December 1972. (U.S. Air Force)
Lockheed SR-71A 61-7953. (U.S. Air Force)Colonel Joseph W. Rogers with a Lockheed “Blackbird.” (U.S. Air Force)
18 December 1969: Colonel Joseph William Rogers and Major Gary Heidelbaugh were flying Lockheed SR-71A 61-7953 to test a new system installation followed by a training mission. The functional test had gone well and the Blackbird rendezvoused with a KC-135 tanker before proceeding with the mission.
After coming off the tanker, Colonel Rogers (call sign “Dutch 68”) radioed the regional air traffic control center for permission to climb through all flight levels to 60,000 feet (18,288 meters), or Flight Level Six Zero Zero.
A short transcript of the radio and intercom transmissions follows:
(Pilot, Colonel Joseph W. Rogers; RSO, Major Gary Heidelbaugh; L.A. Center: Los Angeles Center, the Federal Aviation Administration Air Traffic Control Center at Palmdale, California. Times listed are UTC.)
Pilot’s station of a Lockheed SR-71A. (NASM)
Pilot: “Los Angeles Center, Dutch 68.” [2106:45]
L.A. Center: “Dutch 68, rog, loud and clear. How me?”
Pilot: “Roger, you’re loud and clear. I’m in a left turn flight level two six zero, requesting climb above six zero zero Route Aqua.”
L.A. Center: “Rog, your routing is approved. Climb and maintain above 600 and squawk 4400.”
Pilot: “Four four squawking.” [2107:13]
L.A. Center: “Dutch 68, Rog. Have you radar contact. Report 310 climbing.” [2107:27]
Pilot: “Roger.”
Pilot: “Okay, I’m going to light them off, Gary.” [est 2107:30]
RSO: “Rog.”
RSO: “That’s our heading.”
Pilot: “Roger.”
RSO: “What caused all that?” [est 2108:00]
Pilot: “I don’t know.”
RSO: “. . . Climbing.”
Pilot: “Let’s go.” [est 2108:15] CREW EJECTS
L.A. Center: “Dutch 68. Say your altitude.” [2110:30]
L.A. Center: “Dutch 68. Say your altitude.” [2110:50]
L.A. Center: “Dutch 68, Dutch 68, Los Angeles.” [2111:12]
L.A. Center: “Dutch 68, Dutch 68, Los Angeles.” [2111:28]
When Colonel Rogers advanced the SR-71’s throttles to go into afterburner for the climb, the compressor sections of both engines stalled. (Compressor stall is a condition that occurs when airflow through the engine intake is disrupted. Normal flow ceases, the engine stops producing thrust, and there can be violent oscillations and uncontained failure of the compressor section.) The SR-71A slowed abruptly and then violently pitched upward. Rogers said, “Let’s go,” and both men ejected from the out-of-control airplane.
Rogers and Heidelbaugh safely parachuted to the ground. 61-7953 crashed near Shoshone, California, and was totally destroyed by the crash and fire that followed.
The accident investigation determined that a small roll of 2″-wide (5.08 centimeters) duct tape was lodged inside one of the tubes of the airplane’s pitot-static system. When the new system had been installed, it required that the pitot-static tubing be modified and rerouted. A technician apparently placed the rolled duct tape inside an open section of tubing to prevent entry of dirt or foreign objects. When the tubing was reassembled, this makeshift plug was not removed. Post crash testing showed that the plug did not totally close off airflow, but that it decreased it, causing the altimeter to read too high and the airspeed indicator too fast. The normal test of the pitot-static system following the modification did not reveal the problem.
A Lockheed SR-71 Pratt & Whitney J58 turbo ramjet engine running on a test stand, in full afterburner.
When Joe Rogers advanced the throttles, he was at approximately 27,000 feet (8,230 meters) rather than the indicated 25,000 feet (7,620 meters). He was also about 30 miles per hour (48 kilometers per hour) slower than indicated. The sudden demand for increased airflow as the throttles advanced could not be met by the thinner, slower air, and the compressors stalled.
Joe Rogers was a fighter pilot in World War II, the Korean War and the Vietnam War. He was a highly experienced test pilot with considerable experience in Mach 2+, high-altitude aircraft. He had been the commanding officer of the F-12/SR-71 Test Force at Edwards Air Force Base. Ten years and three days before this accident, he had set a World Speed Record while flying a Convair F-106A Delta Dart. (See TDiA post for 15 December 1959)
The wreck of Lockheed SR-71A 61-7953 burning near Shoshone, California, 18 December 1969. (Check-Six.com)
Sikorsky XHR2S-1, Bu. No. 133732, the first Model S-56, hovers at Sikorsky Aircraft, Bridgeport, Connecticut. (Sikorsky Historical Archives)
18 December 1953: At Bridgeport, Connecticut, Sikorsky chief test pilot Dimitry D. (“Jimmy”) Viner and co-pilot James Edward Chudars made the first flight of the Sikorsky XHR2S-1 (Sikorsky Model S-56). The XHR2S-1 was a prototype assault and heavy-lift helicopter for the United States Navy and Marine Corps. It was later adopted by the U.S. Army as the H-37 Mohave.
The S-56 was a large twin-engine helicopter, following the single main rotor/tail (anti-torque) rotor configuration pioneered by Sikorsky with the Vought-Sikorsky VS-300 in 1939. The helicopter was designed to be flown by two pilots in a cockpit located above the main cabin. The two engines were placed in nacelles outboard of the stub wings which also housed the helicopter’s retractable main landing gear. Two large clam shell cargo doors and loading ramp were placed in the nose. The HR2S-1 incorporated a stability system and an automatic torque compensating tail rotor.
The S-56 series was the largest and fastest helicopter built up to that time, and remains the largest reciprocating engine helicopter ever built.
U.S. Marine Corps HR2S-1 Bu. No. 138423, the seventh production S-56 helicopter (Sikorsky Historical Archives)
The S-56 was equipped with a five blade articulated main rotor. This allowed increased lift and higher forward air speed before encountering retreating blade stall than earlier three and four blade systems. A six blade rotor system was tested, which showed further improvements, but was not adopted. The main rotor diameter was initially 68 feet (20.726 meters), but later increased to 72 feet (21.946 meters). The main rotor blades had a chord of 1 foot, 9.5 inches (0.546 meters) and used the symmetrical NACA 0012 airfoil, which was standard with American helicopters up to that time. Later in the program, the blades were lengthened and the chord increased to 1 foot, 11.65 inches (0.601 meters). The airfoil was changed to the NACA 0010.9 airfoil. These changes resulted in increased lift and higher speed. The four blade tail rotor had a diameter of 15 feet (4.572 meters). The individual blades had a chord of 1 foot, 1.5 inches (0.343 meters). As is common with American helicopters, the main rotor system turned counter-clockwise as seen from above. (The advancing blade is on the right.) The tail rotor turned counter-clockwise when viewed from the helicopter’s left side. (The advancing blade is above the axis of rotation.)
Sikorsky S-56 three-view illustration with dimensions. (Sikorsky Historical Archives)
With the longer blades installed, the helicopter’s length with rotors turning was 88 feet (26.822 meters). The fuselage had a length of 64 feet, 10.69 inches (19.779 meters), and the height was 17 feet, 2 inches (5.232 meters). The HR2S-1 had an empty weight of 21,502 pounds (9,753 kilograms), and maximum weight (overload) of 31,000 pounds (14,061 kilograms). Its fuel capacity was 1,000 U.S. gallons (3,785 liters) carried in 6 tanks located in the nacelles, wings and fuselage. It could carry 20 fully-equipped troops, or 16 litters. Its maximum cargo capacity was 10,000 pounds (4,536 kilograms).
The HR2S-1 had an automatic main rotor blade folding system, and its tail rotor pylon could be folded alongside the fuselage, reducing the length to 55 feet, 8 inches (16.967 meters) and width to 27 feet, 4 inches (8.331 meters). This allowed the helicopter to use aircraft carrier elevators and reduced storage space on the hangar deck.
Early S-56 models were powered by two air-cooled, supercharged 2,804.461 cubic inch displacement (45.957 liters) Pratt & Whitney Double Wasp R-2800-50 two-row, 18-cylinder radial engines rated at 1,900 horsepower at 2,500 r.p.m. These were upgraded in later models to R-2800-54s. These were direct drive engines with a compression ratio of 6.75:1. The R-2800-54 was rated at 2,100 horsepower at 2,700 r.p.m. to 5,000 feet (1,524 meters) for takeoff; with a normal power rating of 1,900 horsepower at 2,600 r.p.m. to 7,000 feet (2,134 meters). It required 115/145 octane aviation gasoline. Each engine was supplied with 13.3 gallons (50.35 liters) of lubricating oil. The R-2800-54 was 6 feet, 9.00 inches long (2.057 meters), 4 feet, 5.00 inches (1.346 meters) in diameter, and weighed 2,300 pounds (1,043 kilograms).
The helicopter’s engines were installed at an 80° angle to the aircraft center line, with a 12.5° upward angle to align with the main transmission input. The front of the engines faced inboard. According to Sikorsky, this unusual installation resulted in high oil consumption, and because the engines were operated at continuous high r.p.m., the time interval between engine overhauls was reduced from the normal 2,000 hours to just 350 hours.
Two U.S. Marine Corps HR2S-1 Mohave assault helicopters of Marine Helicopter Transport Squadron (HMR) 462 at Camp Pendelton, California, late 1950s. (Naval History and Heritage Command)
The production HR2S-1 had a cruise speed of 100 knots (115 miles per hour/185 kilometers per hour), and a maximum speed of 121 knots (139 miles per hour/224 kilometers per hour) at Sea Level. The helicopter’s service ceiling was 13,800 feet (4,206 meters), and its absolute hover ceiling was 5,400 feet (1,646 meters). It had a maximum rate of climb of 1,580 feet per minute (8.03 meters per second) at Sea Level, and a vertical rate of climb 950 feet per minute (4.83 meters per second), also at Sea Level. The combat radius of the HR2S-1 was 100 nautical miles (115 statute miles/185 kilometers) at 100 knots (115 miles per hour/185 kilometers per hour.)
55 HR2S-1s were delivered to the U.S. Marine Corps. The U.S. Army purchased 94 S-56s in the H-37A Mohave configuration. 90 of these were later returned to Sikorsky to be upgraded to H-37Bs. This added the automatic stabilization system of the HR2S-1, changed the variable incidence horizontal stabilizers on both side of the fuselage to a single stabilizer on top of the tail rotor pylon. Engine oil capacity was increased to 30 gallons (113.6 liters) per engine.
A total of 154 S-56s were built between 1953 and 1960.
U.S. Marines exit the front cargo doors of a Sikorsky XHR2S-1 helicopter during a demonstration at Bridgeport, Connecticut, circa 1953. The leading Marine is carrying an M1918 .30-caliber Browning Automatic Rifle (commonly known as the “B-A-R”), while those following are armed with the M1 “Garand” .30-caliber semi-automatic rifle. Note the cinematographer behind the starboard cargo door. (National Archives and Records Administration, NAID: 74241875)
From 9 through 11 November 1956, a U.S. Marine Corps HR2S-1 flown by Major Roy Lee Anderson, USMC, and Sikorsky test pilot Robert S. Decker at Windsor Locks, Connecticut, set three Fédération Aéronautique Internationale (FAI) world records for speed and payload:
On 9 November, the helicopter reached an altitude of 3,722 meters (12,211 feet) with a payload of 5,000 kilograms (11,023 pounds).¹ The following day, 10 November, it set a record for the greatest mass carried to a height of 2,000 meters (6562 feet): 6,010 kilograms (13,250 feet).² Then on 11 November, the HR2S-1 reached a speed of 261.91 kilometers per hour (162.74 mph) over a 3-kilometer (1.86 miles) course.³ For these flights, Major Anderson was awarded a third gold star in lieu of a fourth award of the Distinguished Flying Cross.
Major Roy Lee Anderson, USMC, (left) and Sikorsky test pilot Robert Stewart Decker. (Fédération Aéronautique Internationale)The world-record-setting Sikorsky HR2S-1. Note the dorsal filet. (Fédération Aéronautique Internationale)
First Lieutenant Boyd David Wagner, United States Army Air Corps. (U.S. Air Force)
18 December 1941: First Lieutenant Boyd David (“Buzz”) Wagner, United States Army Air Corps, commanding officer of the 17th Pursuit Squadron (Interceptor) at Nichols Field, Pasay City, Commonwealth of the Philippines, shot down his fifth Japanese airplane, a Mitsubishi A6M2 Type Zero fighter, with his Curtiss-Wright P-40B Warhawk, near Vigan, Luzon. He became the first U.S. Army “ace” of World War II.
On 12 December 1941, “Buzz” Wagner was flying a lone reconnaissance mission over the airfield at Aparri, which had been captured by the invading Japanese. He was attacked by several Zero fighters but he evaded them, then returned and shot down two of them. As he strafed the airfield he was attacked by more Zeros and shot down two more, bringing his score for the mission to four enemy airplanes shot down.
On 18 December, Lieutenant Wagner lead a flight of four P-40s to attack the enemy-held airfield at Vigan. He and Lieutenant Russell M. Church strafed and bombed the field while two other P-40s covered from overhead. Wagner destroyed nine Japanese aircraft on the ground, but as he passed over the field a Zero took off. Wagner rolled inverted to locate the Zero, then after spotting him, chopped his throttle and allowed the Zero to pass him. This left Wagner in a good position and he shot down his fifth enemy fighter. Lieutenant Church was shot down by ground fire and killed.
A Mitsubishi A6M3 Navy Type 0 Model 22, UI 105, (Allied reporting name “Zeke”, but better known simply as “the Zero”) in the Solomon Islands, May 1943. This fighter is flown by Petty Officer 1st Class Hiroyoshi Nishizawa, 251st Kōkūtai, Imperial Japanese Navy Air Service. (Imperial Japanese Navy)
This fifth shoot down made Buzz Wagner the first U.S. Army Air Corps ace of World War II. He was awarded the Distinguished Service Cross, the Distinguished Flying Cross, and the Purple Heart for injuries sustained in an air battle, 22 December 1941. He was evacuated to Australia in January 1942.
2nd Lieutenant Boyd D. Wagner, Air Corps, United States Army.
Boyd David Wagner was born 26 October 1916 at Emeigh, Pennsylvania. He was the first of two children of Boyd Matthew Wagner, a laborer, and Elizabeth Moody Wagner. After graduating from high school, Wagner enrolled in the University of Pittsburgh, where he majored in aeronautical engineering.
After three years of college, Boyd Wagner enlisted as a flying cadet in the U.S. Army Air Corps, at Pittsburgh, Pennsylvania, 26 June 1937. He was commissioned as a Second Lieutenant, Air Corps Reserve, 16 June 1938. Lieutenant Wagner received advanced flight training and pursuit training, and on 1 October 1938 his commission as a reserve officer was changed to Second Lieutenant, Army Air Corps.
Wagner was promoted to First Lieutenant, Army of the United States, on 9 September 1940. Lieutenant Wagner was assigned to the 24th Pursuit Group in the Philippine Islands, 5 December 1940.
1st Lieutenant Boyd David Wagner, United States Army Air Corps, Philippine Islands, 1 December 1941. (Photograph by Carl Mydans/TIME & LIFE Pictures/Getty Images)Lt. Col. Boyd D. Wagner
Lieutenant Wagner was promoted to the rank of Captain, A.U.S., 30 January 1942. On 11 April 1942, Captain Wagner was again promoted, bypassing the rank of Major, to Lieutenant Colonel, A.U.S. He was assigned to the 8th Fighter Group in New Guinea. On 30 April 1942, while flying a Bell P-39 Airacobra, Wagner shot down another three enemy airplanes. In September 1942, Colonel Wagner was sent back to the United States to train new fighter pilots.
On 29 November 1942, Colonel Wagner disappeared while on a routine flight from Eglin Field, Florida, to Maxwell Field, Alabama, in a Curtiss-Wright P-40K Warhawk, 42-10271. Six weeks later, the wreck of his fighter was found, approximately 4 miles north of Freeport, Florida. Lieutenant Colonel Boyd David Wagner, United States Army Air Corps, had been killed in the crash. His remains are buried at Grandview Cemetery, Johnstown, Pennsylvania.
Curtiss-Wright P-40B Warhawks of the 17th Pursuit Squadron, Nichols Field, Luzon, Philippine Islands, early December 1941. This squadron was under the command of 1st Lieutenant Buzz Wagner. (U.S. Air Force)
The Curtiss-Wright Corporation Hawk 81B (P-40B Warhawk) was a single-seat, single-engine pursuit. It was a low-wing monoplane of all-metal construction and used flush riveting to reduce aerodynamic drag. It had an enclosed cockpit and retractable landing gear. Extensive wind tunnel testing at the NACA Langley laboratories refined the airplane’s design, significantly increasing the top speed.
The P-40B Warhawk was 31 feet, 8¾ inches (9.671 meters) long, with a wingspan of 37 feet, 4 inches (11.379 meters) and overall height of 10 feet, 7 inches (3.226 meters). Its empty weight was 5,590 pounds (2,536 kilograms), and 7,326 pounds (3,323 kilograms) gross. The maximum takeoff weight was 7,600 pounds (3,447 kilograms).
Curtiss-Wright P-40B or C Warhawk, circa 1942. (Niagara Aerospace Museum)
The P-40B was powered by a liquid-cooled, supercharged, 1,710.597 cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-C15 (V-1710-33), a single overhead cam (SOHC) 60° V-12 engine, which had a Continuous Power Rating of 930 horsepower at 2,600 r.p.m., from Sea Level to 12,800 feet (3,901 meters), and 1,150 horsepower at 3,000 r.p.m. to 14,300 feet (4,359 meters) for Take Off and Military Power. The engine drove a three-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The V-1710-33 was 8 feet, 2.54 inches (2.503 meters) long, 3 feet, 5.88 inches (1.064 meters) high, and 2 feet, 5.29 inches (0.744 meters) wide. It weighed 1,340 pounds (607.8 kilograms).
Allison Engineering Co. V-1710-33 V-12 aircraft engine at the Smithsonian Institution National Air and Space Museum Steven F. Udvar-Hazy Center. (NASM)
Heavier than the initial production P-40, the P-40B was slightly slower, with a maximum speed of 352 miles per hour (567 kilometers per hour) at 15,000 feet (4,572 meters). It had a service ceiling of 32,400 feet (9,876 meters). Its range was 730 miles (1,175 kilometers).
Armament consisted of two air-cooled Browning AN-M2 .50-caliber machine guns mounted in the cowling and synchronized to fire forward through the propeller arc, with 380 rounds of ammunition per gun, and four Browning AN-M2 .30-caliber aircraft machine guns, with two in each wing.
Curtiss-Wright produced 13,738 P-40s between 1939 and 1944. 131 of those were P-40B Warhawks.
These Curtiss P-40B Warhawks of the 44th Pursuit Squadron, 18th Pursuit Group, are the same type aircraft flown by Buzz Wagner in combat over the Philippine Islands. (U.S. Air Force)
Curtiss-Wright XSB2C-1 Helldiver, Bu. No. 1758, photographed during its first flight, 18 December 1940. (NASM.XXXX.0359-M0001741-00010)
18 December 1940: Longtime Curtiss-Wright Airplane Division test pilot Henry Lloyd Child took the prototype XSB2C-1 for its first flight.
The XSB2C-1 was a large dive bomber, intended to replace the U.S. Navy’s Douglas SBD Dauntless. It was designed by a team lead by Curstiss-Wright chief engineer Raymond Cottrell Blaylock (1904–1973).
The prototype had longitudinal stability problems caused by its relatively short fuselage, required to fit on aircraft carrier flight decks.
While on approach to land, 8 Feb 1941, the XSB2C-1 suffered an engine failure and made a hard landing in an open field. The rear of the fuselage was damaged.
Curtiss-Wright XSB2C-1, Bu. No. 1758, after crash landing 8 February 1941. (NARA)
The prototype was repaired. Its fuselage was lengthened and a larger vertical fin installed to reduce the stability problems. On 21 Dec 1941 the XSB2C-1 was destroyed after wing failure during flight.
The production SB2C-1 Helldiver a large, single engine, low wing airplane, with a two-man crew: the pilot and a radio operator/gunner. It had conventional retractable landing gear. Its wings could be folded for storage aboard aircraft carriers. It was 36 feet, 8 inches (11.176 meters) long, with a wing span of 49 feet, 8-5/8 inches (15.154 meters), and overall height of 13 feet, 1-½ inches (4.005 meters); the height was 16 feet, 10 inches (5.131 meters) with wings folded. The reduced its width to 22 feet, 6-½ inches (6.871 meters).
Curtiss-Wright SB2C-1 Helldiver, three view illustration with dimensions. (U.S. Navy)
The SBC2-1 had a combat weight, empty, of 9,630 pounds (4,368 kilograms). With a 1,000 pound (454 kilogram) bomb and two external fuel tanks tanks, its gross weight was 15,583 pounds (7,068 kilograms); and with a Mk 13 aerial torpedo and two external tanks, 16,812 pounds (7,626 kilograms).
Curtiss-Wright XSB2C-1, Bu. No. 1758, after reconstruction. Note the enlarged tail fin. (Curtiss-Wright Airplane Division)
The XSB2C-1 powered by an air-cooled, supercharged, 2,603.737 cubic inch displacement (42.668 liter) Curtiss-Wright R2600-8 Twin Cyclone (GR2600B698) two-row, 14-cylinder radial engine with a compression ratio of 6.9:1. It was equipped with a Holley Automatic Type Model 1685-H or -HA carburetor. The right-hand drive engine turned a three-bladed Curtiss Electric Propeller with a diameter of 12 feet (3.658 meters) through a reduction gear ratio of 0.5625:1. The engine required 100-octane aviation gasoline and was rated at 1,500 horsepower at 2,400 rpm; 1,700 horsepower at 2,600 r.p.m., military power; and 1,700 horsepower at 2,800 r.p.m. for takeoff. The R2600-8 was 5 feet, 4.91 inches (1.649 meters) long, 4 feet, 6.26 inches (1.378 meters) in diameter, and weighed 1,995 pounds (905 kilograms). 11,410 of this engine variant were built between April 1940 and May 1944.
The SB2C-1 had a total fuel capacity of 290 gallons (1,098 liters) in one fuselage tank and two wing tanks. An additional 130 gallon (492 liters) tank could be installed in the bomb bay.
The prototype Curtiss-Wright XSB2C-1 Helldiver, Bu. No. 1758, photographed 12 December 1940. (Curtiss-Wright Airplane Division)
The Helldiver’s armament consisted of four air-cooled AN-M2 .50 caliber machine guns in the wings with 240 rounds per gun. A single .50 caliber machine gun with 150 rounds of ammunition was installed in the aft compartment on a flexible mount. After first 200 production airplanes, the wing machine guns were replaced with two 20 mm automatic cannon, while two .30 caliber machine guns replaced the single aft .50 caliber gun.
The SB2C-1 had a maximum speed 250 miles per hour (402 kilometers per hour) at Sea Level, and maximum speed of 273 miles per hour (439 kilometers per hour)at 13,400 feet (4,084 meters). Its service ceiling was 22,800 feet (6,949 meters). It could climb from Sea Level to to climb to 10,000′ (3,048 meters) in 9.7 minutes, and to 20,000 feet (6,096 meters) 32.6 minutes. The dive bomber’s combat radius, with two 1,000 pound (454 kilogram) bombs and two external fuel tanks was 365 nautical miles (676 kilometers). It had a maximum range of max range 1,375 nautical miles (2,547 kilometers).
Curtiss-Wright XSB2C-1, Bu. No. 1758, after reconstruction. Note the enlarged tail fin. (Curtiss-Wright Airplane Division)
7,141 SBC2 Helldivers were built in several variations. 300, designated SBF, were built by Fairchild Aircraft Ltd. (Canada), Longueuil, Quebec; and 834 SBWs by the Canadian Car & Foundry at Fort William, Ontario.
The U.S Army ordered 3,100 Helldiver variants as the A-25A Shrike, but found the airplane inferior in the ground attack role to the Republic Aviation P-47 Thunderbolt. The contract was cancelled with just 900 A-25s produced. These were modified back to the Navy variant and transferred to the U.S. Marine Corps.
