14 October 1938: At Buffalo, New York, test pilot Everett Edward Elliot made the first flight in the new Curtiss-Wright Corporation’s Model 75P, a prototype for a single-engine pursuit plane which had been designated XP-40 by the U.S. Army Air Corps.
Curtiss-Wright’s Chief Engineer, Donovan Reese Berlin, had taken the tenth production P-36A Hawk, Air Corps serial number 38-10, and had its air-cooled radial engine replaced with the Harold Caminez-designed, liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-C13 (V-1710-19).
The V-1710-19 was a single overhead cam (SOHC) 60° V-12 engine with four valves per cylinder and a compression ration of 6.65:1. It had a Normal Power rating of 910 horsepower at 2,600 r.p.m. at Sea Level, and 1,060 horsepower at 2,950 r.p.m. for Takeoff. At 10,000 feet (3,048 meters), the V-1710-19 had Maximum Continuous Power rating of 1,000 horsepower at 2,600 r.p.m., and Military Power rating of 1,150 horsepower at 2,950 r.p.m. The engine required 100/130-octane aviation gasoline. It drove a three-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The V-1710-19 was 8 feet, 1.75 inches (2.483 meters) long, 3 feet, 4.75 inches (1.035 meters) high and 2 feet, 4.94 inches (0.735 meters) wide. It weighed 1,320 pounds (599 kilograms).
At 1,829.39-cubic-inches (29.978 liters), the original Pratt & Whitney Twin Wasp S1C1-G (R-1830-17) 14-cylinder radial engine had greater displacement and produced 80 horsepower more for takeoff than the Allison V-12. The long, narrow V-12, though, allowed for a much more streamlined engine cowling for higher speed and greater efficiency.
In the early testing, the XP-40 was much slower than expected, reaching only 315 miles per hour (507 kilometers per hour). (The P-36A Hawk had a maximum speed of 313 miles per hour). Engineers experimented with different placement for the coolant radiator, oil coolers and the engine air intake. The Air Corps project officer, Lieutenant Benjamin Scovill Kelsey, had the prototype sent to the National Advisory Committee for Aeronautics (NACA) Research Center at Langley Field, Virginia, where the full-size airplane was placed inside a wind tunnel.
Over a two-month period, NACA engineers made a number of improvements. The radiator was moved forward under the engine and the oil coolers utilized the same air scoop. The exhaust manifolds were improved as were the landing gear doors.
When they had finished, Lieutenant Kelsey flew the modified XP-40 back to Curtiss. Its speed had been increased to 354 miles per hour (570 kilometers per hour), a 12% improvement.
By December 1939 the airplane had been further improved and was capable of 366 miles per hour (589 kilometers per hour).
The Curtiss Hawk 75P, XP-40 38-10, was 31 feet, 1 inch (9.574 meters) long with a wingspan of 37 feet, 4 inches (11.354 meters) and overall height of 12 feet, 4 inches (3.734 meters). It had an empty weight of 5,417 pounds (2,457.1 kilograms) and maximum gross weight of 6,870 pounds (3,116.2 kilograms).
The prototype had a maximum speed of 342 miles per hour (550 kilometers per hour) at 12,200 feet (3,719 meters) with a gross weight of 6,260 pounds (2,839.5 kilograms). Its range was 460 miles (740 kilometers) flying at 299 miles per hour (481 kilometers per hour) with 100 gallons (378.5 liters) of fuel. With 159 gallons (601.9 liters) and with speed reduced to 200 miles per hour (322 kilometers per hour), the XP-40 had a maximum range of 1,180 miles (1,899 kilometers).
The prototype was armed with two air-cooled Browning AN-M2 .50-caliber machine guns mounted above the engine and synchronized to fire forward through the propeller arc.
The Air Corps placed an initial order for 524 P-40s. This was the largest single order for airplanes by the U.S. military up to that time. The first production model was the P-40 Warhawk, armed with two .50-caliber machine guns. There was only one P-40A variant which was a P-40 modified as a camera aircraft. The definitive pursuit model was the P-40B Warhawk, which retained the two .50-caliber guns of the P-40 and added two Browning M2 .30-caliber machine guns to each of the wings.
The P-40B was best known as the airplane flown by the American Volunteer Group fighting for China against the Japanese. They were called the “Flying Tigers”. Between 1939 and 1945, Curtiss built 13,738 P-40s in many configurations. They flew in combat in every theater of operations during World War II.
2 September 1944: Lieutenant (Junior Grade) George Herbert Walker Bush, United States Naval Reserve, led a flight of four TBF/TBM Avenger torpedo bombers of Torpedo Squadron 51 (VT-51), from the Independence-class light aircraft carrier USS San Jacinto (CVL-30), against a radio transmission station on the island of Chichi-Jima.
The Avenger had a crew of three. Along with Lt (j.g.) Bush were Lt. (j.g.) William G. White, USNR, gunner, and radio operator ARM 2/c John Lawson Delaney, USNR.
Each airplane was armed with four 500-pound¹ general purpose bombs. The flight was joined by eight Curtiss-Wright SB2C Helldiver dive bombers of VB-20, escorted by twelve Grumman F6F-5 Hellcat fighters of VF-20, from USS Enterprise (CV-6).
Chichi-Jima is the largest island in the Ogasawara Archipelago of the Bonin Islands, approximately 150 miles (240 kilometers) north of Iwo Jima and 620 miles (1,000 kilometers) south of Tokyo, Japan. The United States Hydrographic Survey described the island in 1920 as “very irregular in shape,” approximately 4¼ miles (7.2 kilometers) long and 2 miles (3.2 kilometers) wide. The area of the island is presently given as 23.45 square kilometers (9.05 square miles). Its highest point is 326 meters (1,070 feet) above Sea level. The island has a small sea port where midget submarines were based beginning in August 1944. Chichi-Jima was heavily garrisoned with 20,656 Imperial Japanese Army and Navy personnel, and 2,285 civilian workers.²
Lieutenant Bush’s flight was scheduled for a time over target of 0825–0830. They encountered heavy antiaircraft fire and Bush’s Avenger was hit. With the torpedo bomber on fire, Bush continued the attack and later reported good results. Unable to return to the aircraft carrier, he flew away from the island to limit the risk of capture of the crew by the enemy when they bailed out.
Bush and one other crewman (which one is not known) bailed out. While Bush parachuted safely, the second crewman’s parachute never opened. The third crewman went down with the airplane. Both Lieutenant White and Radioman Delaney were killed.
The Gato-class fleet submarine USS Finback (SS-230) was stationed near the island on lifeguard duty during the attack. At 0933, Finback was notified of an aircraft down nine miles northeast of Minami-Jima. Escorted by two F6F fighters, the submarine headed for the location. At 1156, Finback picked up Lt. Bush, floating in his life raft. A search for White and Delaney was unsuccessful. Their bodies were not recovered.
(Later that same day, Finback, while submerged, towed a second pilot and his life raft away from Magane-Iwa, as he held on to the sub’s periscope.)
Lieutenant Bush and the other rescued pilots remained aboard for the remainder of Finback‘s war patrol (her tenth), and were then returned to Pearl Harbor. In November he rejoined San Jacinto for operations in the Philippines.
George Herbert Walker Bush was born at Milton, Massachusetts, 12 June 1924, the son of Prescott Sheldon Bush and Dorothy Walker Bush. He attended high school at the Phillips Academy in Andover, Massachusetts.
One day after his 18th birthday, 13 June 1942, Bush enlisted as a seaman, 2nd class, in the United States Naval Reserve. He was appointed an aviation cadet and underwent preflight training at the University of North Carolina, Chapel Hill. He was honorably discharged 8 June, and commissioned as an ensign, United States Naval Reserve, 9 June 1943. At the age of 19 years, 2 days, he became the youngest Naval Aviator in history. (His age record was broken the following month by Ensign Charles Stanley Downey, who was commissioned 16 July 1943 at the age of 18 years, 11 months, 14 days.)
Ensign Bush continued flight training at NAS Pensacola, Florida, and then the Carrier Qualification Training Unit, NAS Glenville, Illinois. After training with the Atlantic Fleet, Ensign Bush was assigned to Torpedo Squadron Fifty-One (VT-51), in September 1943. He was promoted to lieutenant (junior grade), 1 August 1944.
After leaving San Jacinto, Bush was assigned to NAS Norfolk, Virginia, from December 1944 to February 1945. He then joined Torpedo Squadron Ninety-Seven (VT-97) and then VT-153.
Lieutenant (j.g.) Bush was released from active duty on 18 September 1945, retaining his commission. He was promoted to lieutenant 16 November 1948. On 24 October 1955, Lieutenant Bush resigned from the U.S. Navy.
During World War II, George H. W. Bush flew 58 combat missions. He flew a total of 1,221 hours and made 126 carrier landings. He was awarded the Distinguished Flying Cross, the Air Medal with two gold stars (three awards), and the Presidential Unit Citation.
He would later become the forty-first President of the United States of America.
The airplane flown by Lt. (j.g.) Bush on 2 September 1944 was a General Motors TBM-1C Avenger torpedo bomber, Bu. No. 46214. This was a licensed variant of the Grumman TBF-1C Avenger, built by the General Motors Corporation Eastern Aircraft Division at Linden, New Jersey.
The Avenger was designed by Robert Leicester Hall, Chief Engineer and Test Pilot for the Grumman Aircraft Engineering Corporation, Bethpage, New York. The prototype XTBF-1 made its first flight 1 August 1941. It was a large single-engine aircraft, operated by a crew of three (pilot, radio operator and ball turret gunner). It was equipped with folding wings for storage on aircraft carriers. Production of the torpedo bomber began with the opening of a new manufacturing plant, Sunday, 7 December 1941. The first production Avenger was delivered to the U.S. Navy in January 1942.
The TBF-1 and TBM-1 were 40 feet, 11 inches (12.471 meters) long, with a wingspan of 54 feet, 2 inches (16.510 meters) and overall height of 16 feet, 5 inches (5.004 meters). The airplane had an empty weight of 10,545 pounds (478 kilograms), and its maximum gross eight was 17,895 pounds (8,117 kilograms). The Avenger was the largest single-engine aircraft of World War II.
The Avenger was powered by one of several variants of the Wright Aeronautical Division Cyclone 14 (R-2600): GR2600B698 (R-2600-8 and -8A); GR2600B676 (R-2600-10); and 776C14B31. The R-2600 was series of air-cooled, supercharged, 2,603.737-cubic-inch-displacement (42.688 liter), two-row 14-cylinder radial engines. The engines used in the Avengers all had a compression ratio of 6.9:1, supercharger ratios of 7.06:1 and 10.06:1, and propeller gear reduction ratio of 0.5625:1.
The R-2600-8, -8A and -10 had Normal Power ratings of 1,500 horsepower at 2,400 r.p.m. at Sea Level, and 1,700 horsepower at 2,600 r.p.m. for takeoff. The R-2600-20 was rated at 1,600 horsepower at 2,400 r.p.m., and 1,900 horsepower at 2,800 horsepower, respectively.
Dimensions and weights varied. The R-2600-8 and -8A were 64.91 inches (1.649 meters) long. The -10 was 74.91 inches (1.903 meters) long, and the length of the -20 was 66.08 inches (1.678 meter). The R-2600-8 and 8A and -10 were 54.26 inches (1.378 meters) in diameter. The -20 was 54.08 inches (1.374 meters). The -8 and -8A both weighed 1,995 pounds (905 kilograms). The -10 weighed 2,115 pounds (959 kilograms) and the -20 weighed 2,045 pounds (928 kilograms).
The engines drove a three-bladed Hamilton Standard Hydromatic constant-speed propeller.
The TBF/TBM had a cruise speed of 147 miles per hour (237 kilometers per hour) and maximum speed of 276 miles per hour (444 kilometers per hour) at 16,500 feet (5,029 meters). The service ceiling was 30,100 feet (9,174 meters). Its maximum range was 1,010 miles (1,625 kilometers).
The Avenger was armed with one air-cooled Browning AN-M2 .50-caliber machine gun mounted in each wing, firing forward. Another .50-caliber machine gun was installed in an electrically-operated dorsal ball turret. In the ventral position was a Browning M2 .30-caliber aircraft machine gun in a flexible mounting.
The primary weapon of the Avenger was carried in an enclosed weapons bay. It could be armed with one Mk. 13 aerial torpedo, ³ or up to 2,000 pounds (907 kilograms) of bombs.
The Grumman Aircraft Engineering Corporation produced TBF Avengers from Early 1942 until 1943, when production was taken over by the General Motors Corporation Eastern Aircraft Division. Grumman produced 2,290 TBFs, while Eastern built 9,836 TBMs.
Lieutenant Bush’s aircraft carrier, USS San Jacinto (CVL-30), was an Independence-class light carrier. It had been started by the New York Shipbuilding Corporation as a Cleveland-class light cruiser, USS Newark (CL-100), but was converted during construction. Construction took 11 months and the ship was launched 26 September 1943. It was commissioned 15 November 1943.
The carrier was 622.5 feet (189.7 meters) long, with a beam of 71.5 feet (21.8 meters) and draft of 26 feet (7.9 meters). It had a full load displacement of 15,100 long tons (16,912 short tons, or 15,342 metric tons). The ship was powered by steam turbines producing 100,000 horsepower and driving four shafts. San Jacinto was capable of a maximum 31.6 knots (36.4 miles per hour, or 58.5 kilometers per hour).
San Jacinto had a complement of 1,549 men, and carried 45 airplanes. For defense, it was armed with 28 Bofors 40 millimeter anti-aircraft guns and 40 Oerlikon 20 millimeter autocannon.
San Jacinto was decommissioned 1 March 1947 and was later scrapped.
On 7 October 2006, the tenth and final Nimitz-class supercarrier was christened USS George H.W. Bush (CVN-77) in honor of President Bush’s service to his country.
¹ The most common U.S. 500-pound general purpose bomb of World War II was the AN-M64. Nominally a 500-pound (227 kilogram) bomb, the munition actually weighed from 516.3 to 535.4 pounds (234.2 to 242.9 kilograms), depending on the explosive used. It contained 266 pounds (120.7 kilograms) of TNT, or 258.5 pounds (117.3 kilograms) of a 50/50 TNT and Amatol mixture. For easy identification, these were marked with a single 1-inch (2.54 centimeter) wide yellow band painted at the nose and tail. Composition B bombs, which were marked with two yellow identification bands, contained 272.7 pounds (123.7 kilograms) of explosive, while the heaviest was filled with 278.3 pounds (126.2 kilograms) of Tritonal. This variant was marked with three yellow bands. The bomb, without fins or fuses, was 36 inches (0.914 meters) long. The overall length was 59.16 inches (1.503 meters), including nose and tail fuses. The maximum diameter was 10.9 inches (0.277 meters).
² Personnel numbers as of 3 September 1945.
³ The U.S. Navy Torpedo, Mark 13, was a gyroscopically-steered single-speed anti-ship torpedo designed to be dropped from aircraft. It was 13 feet, 8.55 inches (4.180 meters) long, 1 foot, 10.42 inches (0.570 meters) in diameter and weighed 1,949 pounds (884 kilograms) ± 20 pounds (9 kilograms). The warhead contained a 400 pound (181 kilogram) TNT explosive charge. The Mk. 13 was driven by a two-stage alcohol-fueled geared steam turbine, turning 10,983 r.p.m., with the coaxial counter-rotating propellers turning 1,150 r.p.m. It was capable of running at 33.5 knots (38.6 miles per hour, or 62.0 kilometers per hour), with a range of 6,300 yards (5.8 kilometers). This same type torpedo was used by the U.S. Navy’s PT boats late in the war.
Thanks to regular TDiA reader Joolz Adderly for suggesting this topic.
19 August 1940: At Mines Field (now known as Los Angeles International Airport), the first North American Aviation B-25 twin-engine medium bomber, serial number 40-2165, took off on its first flight with test pilot Vance Breese at the controls and engineer Roy Ferren in the co-pilot’s position.
The airplane, North American model NA-62, serial number 62-2834, was developed from two earlier designs which had been evaluated by the U.S. Air Corps but rejected, and it was ordered into production without a prototype being built.
The first few B-25s built—sources vary, but 8–10 airplanes—were built with a constant dihedral wing. Testing at Wright Field showed that the airplane had a slight tendency to “Dutch roll” so all B-25s after those were built with a “cranked” wing, with the outer wing panels having very slight dihedral ¹ and giving it the bomber’s characteristic “gull wing” appearance. The two vertical stabilizers were also increased in size.
40-2165 was retained by North American for testing while the next several aircraft were sent to Wright Field.
The B-25 was named Mitchell in honor of early air power advocate Brigadier General Billy Mitchell. A total of 9,984 B-25s, F-10 reconnaissance variants and U.S. Navy and Marine Corps PBJ-1 patrol bombers were built by North American Aviation at Inglewood, California and Kansas City, Kansas. The last one, a TB-25J, remained in service with the U.S. Air Force until 1960.
Twenty-three B-25s were built before the B-25A Mitchell went into production. The B-25 was operated by a crew of five. It was 54 feet, 1 inch (16.485 meters) long with a wingspan of 67 feet, 6.7 inches (20.592 meters) and overall height of 16 feet, 4 inches (4.978 meters). The empty weight was 17,258 pounds (7,828 kilograms) and the maximum gross weight was 28,557 pounds (12,953 kilograms).
The B-25 was powered by two air-cooled, supercharged, 2,603.737-cubic-inch-displacement (42.688 liter) Wright Aeronautical Division Cyclone 14 GR2600B665 (R-2600-9) two-row 14-cylinder radial engines which were rated at 1,500 horsepower at 2,400 r.p.m., and 1,700 horsepower at 2,600 r.p.m. for takeoff. These engines (also commonly called “Twin Cyclone”) drove three-bladed Hamilton Standard Hydromatic variable-pitch propellers through 16:9 gear reduction. The R-2600-9 was 5 feet, 3.1 inches (1.603 meters) long and 4 feet, 6.26 inches (1.378 meters) in diameter. It weighed 1,980 pounds (898 kilograms).
The medium bomber had a maximum speed of 322 miles per hour (518 kilometers per hour) at 15,000 feet (4,572 meters) and a service ceiling of 30,000 feet (9,144 meters). It could carry a 3,000 pound bomb load 2,000 miles (3,219 kilometers).
Defensive armament consisted of three air-cooled Browning M2 .30-caliber aircraft machine guns and one Browning AN-M2 .50-caliber machine gun.
After testing was completed, B-25 40-2165 was retained by North American and modified as a company transport. On 8 January 1945, flown by Edgar A. Stewart, the airplane suffered an engine failure and made a forced landing at Mines Field—the location of its first flight. The prototype B-25 was damaged beyond repair.
¹ The wing center section of the B-25H and B-25J has 4° 38′ 23″ dihedral. The outer sections have 0° 21′ 39″. The wing has 2° 29′ 37″ negative twist.
17 August 1942: Mission No. 1. The United States VIII Bomber Command made its first heavy bomber attack on Nazi-occupied Europe when eighteen Boeing B-17E Flying Fortress four-engine bombers of the 97th Bombardment Group (Heavy), based at RAF Polebrook, Northamptonshire, England, headed for the railroad marshaling yards at Rouen-Sotteville, France. This was the largest and most active railroad yard in northern France.
The group began takeoffs at 1530 hours. It was escorted by several squadrons of Royal Air Force Supermarine Spitfire fighters.
While six B-17s flew along the French coast as a diversion, twelve bombers flew to Rouen and were over the target from 1739 to 1746. From an altitude of 23,000 feet (7,010 meters), they dropped 39,000 pounds (17,690 kilograms) of general purpose bombs.
Accuracy was good. One of the aim points, the locomotive shops, was destroyed by a direct hit. The overall results were moderate.
All of the bombers returned to their base, with the first landing at 1900. Two B-17s had been damaged. American gunners claimed damage to one Luftwaffe airplane.
The raid was commanded by Brigadier General Ira C. Eaker aboard Yankee Doodle, B-17E 41-9023, leading the second flight of six B-17s. The 97th Bombardment Group Commander, Colonel Frank A. Armstrong, Jr., flew as the co-pilot of the lead ship, Butcher Shop, B-17E 41-2578, with pilot Major Paul W. Tibbets, Jr. Major Tibbets was in command of the 97th’s 340th Bombardment Squadron. (He would later command the 509th Composite Group and fly the B-29 Superfortress Enola Gay.)
The Boeing B-17E Flying Fortress was a major redesign. A new aft fuselage was used, incorporating larger vertical and horizontal stabilizers. A tail turret was added. A power-operated gun turret was added at dorsal and ventral positions.
The Boeing B-17E Flying Fortress was a four-engine heavy bomber operated by a flight crew of ten. It was 73 feet, 10 inches (22.504 meters) long with a wingspan of 103 feet, 9-3/8 inches (31.633 meters) and an overall height of 19 feet, 2 inch (5.842 meters). Its empty weight was 32,350 pounds (14,674 kilograms), 40,260 pounds (18,262 kilograms) gross weight, and the maximum takeoff weight was 53,000 pounds (24,040 kilograms).
The B-17E was powered by four air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.875 liters) Wright Cyclone G666A (R-1820-65) nine-cylinder radial engines with turbochargers, producing 1,200 horsepower at 2,500 r.p.m. for takeoff and 1,000 horsepower at 2,300 r.p.m. at Sea Level. The Cyclones turned three-bladed constant-speed Hamilton-Standard Hydromatic propellers with a diameter of 11 feet, 7 inches (3.835 meters) though a 0.5625:1 gear reduction. The R-1820-65 was 47.59 inches (1.209 meters) long and 55.12 inches (1.400 meters) in diameter. It weighed 1,315 pounds (596 kilograms). 8,422 of these engines were produced by Wright Aeronautical Division and its licensees between February 1940 and August 1942.
The B-17E had a cruise speed of 195 miles per hour (314 kilometers per hour). Its maximum speed was 318 miles per hour (512 kilometers per hour) at 25,000 feet (7,620 meters). The service ceiling was 36,600 feet (11,156 meters).
With a normal fuel load of 2,490 gallons (9,426 liters) the B-17E had a maximum range of 3,300 miles (5,311 kilometers). Carrying a 4,000 pound (1,814 kilogram) bomb load, the range was 2,000 miles (3,219 kilometers).
The B-17E Flying Fortress was armed with one .30-caliber Browning M2 Aircraft Machine Gun and eight Browning AN-M2 .50-caliber machine guns. The .30 was mounted in the nose. Power turrets mounting two .50-caliber guns, each, were located at the dorsal and ventral positions. (The first 112 B-17Es were built with a remotely-operated turret in the belly position, sighted by a periscope. A manned ball turret replaced this.) Two machine guns were in a tail turret, and one on each side at the waist.
The maximum bomb load of the B-17E was 20,800 pounds (9,435 kilograms) over very short distances. Normally, 4,000–6,000 pounds (1,815–2,722 kilograms) were carried. The internal bomb bay could be loaded with a maximum of eight 1,000 pound (454 kilogram) or four 2,000 pound (907 kilogram) bombs.
The B-17 Flying Fortress first flew in 1935, and was in production from 1937 to 1945. 12,731 B-17s were built by Boeing. 512 of the total were B-17Es. The last one was completed 28 May 1942. Production shifted to the further-improved B-17F.
28 July 1935, At Boeing Field, Seattle, Chief Test Pilot Leslie Ralph (“Les”) Tower and Louis Waite took off on the maiden flight of the Boeing Model 299, NX13372, a prototype four-engine long range heavy bomber. For approximately one-and-a-half hours, Tower flew back and forth between Tacoma and Fort Lewis. When he landed, he said, “It handles just like a little ship—a little bigger, of course.”
The Boeing Model 299 was a four-engine bomber operated by a crew of eight. It wasdesigned to meet a U.S. Army Air Corps proposal for a multi-engine bomber that could carry a 2,000 pound (907 kilogram) bomb load a distance of 2,000 miles (3,219 kilometers) at a speed greater than 200 miles per hour (322 kilometers per hour). Design of the prototype began in June 1934 and construction was started 16 August 1934. The Air Corps designated it B-299, and later, XB-17. It did not carry a military serial number, being marked with civil registration NX13372.
The Model 299 was 68 feet, 9 inches (20.955 meters) long with a wingspan of 103 feet, 9–3/8 inches (31.633 meters) and height of 14 feet, 11–5/16 inches (4.554 meters). Its empty weight was 21,657 pounds (9,823 kilograms). The maximum gross weight was 38,053 pounds (17,261 kilograms).
The prototype was powered by four air-cooled, supercharged, 1,690.537-cubic-inch-displacement (27.703 liter) Pratt & Whitney Hornet S1E-G nine-cylinder radial engines with a compression ratio of 6.5:1. The S1E-G was rated at 750 horsepower at 2,250 r.p.m., and 875 horsepower at 2,300 r.p.m. for takeoff, using 87-octane gasoline. They turned 11 foot, 6 inch (3.505 meters) diameter, three-bladed, Hamilton Standard Hydromatic constant-speed propellers through a 3:2 gear reduction. The S1E-G was 4 feet, 1.38 inches (1.254 meters) long, 4 feet, 6.44 inches (1.383 meters) in diameter and weighed 1,064 pounds (483 kilograms)
In flight testing, the Model 299 had a cruise speed of 204 miles per hour (328 kilometers per hour) and a maximum speed of 236 miles per hour (380 kilometers per hour) at 10,000 feet (3,048 meters). The service ceiling was 24,620 feet (7,504.2 meters). Its maximum range was 3,101 miles (4,991 kilometers). Carrying a 2,573 pounds (1,167 kilograms) load of bombs, the range was 2,040 miles (3,283 kilometers).
The XB-17 could carry eight 500 pound (226.8 kilogram) bombs in an internal bomb bay. Defensive armament consisted of five air-cooled Browning .30-caliber machine guns.
NX13372 was destroyed when it crashed on takeoff at Wright Field, Dayton, Ohio, 30 October 1935. An Army Air Corps pilot making his first familiarization flight neglected to remove the control locks. This incident led directly to the creation of the ”check list” which is used by all aircraft crew members.
Designated XB-17 by the Army Air Corps, this airplane and the YB-17 pre-production models that followed would undergo several years of testing and improvement before entering production as the B-17 Flying Fortress, a legendary airplane of World War II. By the end of the war 12,731 B-17s had been built by Boeing, Douglas and Lockheed Vega.