Tag Archives: 17th Bombardment Group (Medium)

2 April 1942

B-25 Mitchell bombers aboard USS Hornet (CV-8), with USS Gwin (DD-433) and USS Nashville (CL-43), somewhere in the Pacific, April 1942. (U.S. Navy)
B-25 Mitchell bombers aboard USS Hornet (CV-8), with USS Gwin (DD-433) and USS Nashville (CL-43), somewhere in the Pacific, April 1942. (U.S. Navy)

2 April 1942: After loading sixteen North American Aviation B-25B Mitchell medium bombers and their crews of the 17th Bombardment Group (Medium) at NAS Alameda, the recently commissioned United States Navy aircraft carrier USS Hornet (CV-8) departed San Francisco Bay with her escorts and headed for a secret rendezvous with Vice Admiral William F. Halsey, Jr., and Task Force 16.

The new carrier was under command of Captain Marc A. Mitscher. The strike group was commanded by Lieutenant Colonel James H. (“Jimmy”) Doolittle, U.S. Army Air Corps. Until the second day at sea, only six U.S. military officers knew of the mission.

The photograph above shows some of the bombers secured on Hornet‘s flight deck. An escorting destroyer, USS Gwin (DD-433) is closing from astern, with light cruiser USS Nashville (CL-43) in the distance. Two more ships are on the horizon.

USS Hornet (CV-8), 27 October 1942. (U.S. Navy)
USS Hornet (CV-8), Captain Marc A. Mitscher, U.S.N., commanding, 27 October 1942. The aircraft carrier is painted in Measure 12 camouflage, Sea Blue 5-S, Ocean Gray 5-O and Haze Gray 5-H. (U.S. Navy)

USS Hornet was a brand new Yorktown-class aircraft carrier, commissioned 20 October 1941. It had just completed its shakedown cruise in the Atlantic when it was sent west for this mission.

The ship was 824 feet, 9 inches (251.384 meters) long, overall, with a maximum width of 114 feet (34.747 meters). Hornet‘s dimensions at the waterline (full load displacement) were 761 feet (232 meters) long with a beam of 83 feet, 3 inches (25.375 meters). Its draft was 28 feet (8.5 meters).

The flight deck had two hydraulic catapults, and three elevators for bringing aircraft up from the hangar deck. A third catapult was on the hangar deck, launching aircraft laterally.

Powered by four geared steam turbines driving four propeller shafts, Hornet‘s engines produced 120,000 shaft horsepower. The carrier’s maximum speed was 33.84 knots (39.94 miles per hour/62.67 kilometers per hour), and maximum range, 12,500 nautical miles (14,385 kilometers).

North American Aviation B-25B Mitchell medium bomber tied down on the flight deck of U.S.S. Hornet (CV-8). An escorting destroyer, USS Gwin, (DD- ) closes on the carrier's right rear quarter. (U.S. Navy)
A 17th Bombardment Group North American Aviation B-25B Mitchell medium bomber tied down on the flight deck of U.S.S. Hornet (CV-8). An escorting destroyer, USS Gwin, (DD-433 ), Commander John S. Higgins, U.S.N., commanding, closes on the carrier’s right rear quarter. The sixteen Army bombers used all the space available on Hornet’s flight deck.(U.S. Navy)

The aircraft carrier’s primary armament was its air wing, consisting of a squadron each of Grumman F4F Wildcat fighters, Douglas SBD Dauntless dive bombers and Douglas TBD Devastator torpedo bombers. For the Halsey-Doolittle Raid, Hornet‘s air wing was stored on the hangar deck and unavailable.

“To make room for the Army bombers, Hornet had struck her own planes below. Wildcats and Devastators, with wings folded, and dismantled SBDs were packed into every available space, even hung from the overhead. So, except for her few guns, the carrier was defenseless until she rendezvoused with Task Force 16. . . .”

History of United States Naval Operations in World War II, Volume III, The Rising Sun in the Pacific, by Samuel Eliot Morison, Little, Brown & Company, Boston, 1988, Chapter XX at Page 392.

For defense, the ship was lightly armored, with 2.5–4 inches (6.35–10.2 centimeters) of belt and deck armor. She also carried eight 5-inch, 38-caliber (5″/38) dual-purpose guns in single mounts, thirty 20mm Oerlikon autocannon, twenty water-cooled 1.1-inch, 75-caliber (1.1″/75) guns in four-gun mounts, and twenty-four Browning .50-caliber (12.7 millimeter) machine guns.

Including the ship’s air wing, the complement was 2,919 men.

USS Hornet fought at the Battle of Midway, June 3–7, 1942. She was sunk at the Battle of the Santa Cruz Islands, 26 October 1942, having been hit by two airplanes, 8 bombs, 16 torpedoes and an unknown number of 5-inch shells.¹

USS Hornet (CV-8) at Peral Harbor, Hawaii, following the Halsey-Doolittle Raid, 1942. The ships is painted in Measure 12 (Modified) camouflage, with Sea Blue 5-s, Ocean Gray 5-O and Haze Gray 5-H coloration.
USS Hornet (CV-8) at Pearl Harbor, Hawaii, following the Halsey-Doolittle Raid, 1942. The ship is painted in Measure 12 (Modified) camouflage with splotches, with Navy Blue 5-N, Sea Blue 5-S, Ocean Gray 5-O and Haze Gray 5-H coloration.

¹ The research vessel R/V Petrel located the wreck of USS Hornet on the sea floor in January 2019. The ship lies at a depth of 5,330 meters (17,487 feet).

© 2019, Bryan R. Swopes

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27 March 1942

North American Aviation B-25B Mitchell 40-2291 at Eglin Field, Florida, March 1942. (U.S. Air Force)

27 March 1942: After three weeks of intensive training at Eglin Field, Florida, twenty-two North American Aviation B-25B Mitchell twin-engine medium bombers of the 34th Bombardment Squadron (Medium), 17th Bombardment Group (Medium), U.S. Army Air Force, under the command of Lieutenant Colonel James Harold Doolittle, completed a two-day, low-level, transcontinental flight, and arrived at the Sacramento Air Depot, McClellan Field, California, for final modifications, repairs and maintenance before an upcoming secret mission: The Halsey-Doolittle Raid.

The B-25 had made its first flight 19 October 1940 with test pilot Vance Breese and engineer Roy Ferren in the cockpit. It was a mid-wing airplane with twin vertical tails and retractable tricycle landing gear. The first 8–10 production 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, using dihedral for the inner wing and anhedral in the wing outboard of the engines. This gave it the bomber’s characteristic “gull wing” appearance. The two vertical stabilizers were also increased in size.

A 34th Bombardment Squadron B-25B Mitchell bomber at Mid-Continent Airlines, Minneapolis, Minnesota, for modifications, January–February 1942. (U.S. Air Force)

The B-25B Mitchell was operated by a crew of five: two pilots, a navigator, bombardier and radio operator/gunner.  It was 53 feet, 0 inch (16.154 meters) long with a wingspan of 67 feet, 7.7 inches (20.617 meters) and overall height of 15 feet, 9 inches (4.801 meters). The The B-25B had an empty weight of 20,000 pounds (9,072 kilograms) and the maximum gross weight was 28,460 pounds (12,909 kilograms).

The B-25B was powered by two air-cooled, supercharged, 2,603.737-cubic-inch-displacement (42.668 liter) Wright Aeronautical Division Cyclone 14 GR2600B665 (R-2600-9) two-row 14-cylinder radial engines with a compression ratio of 6.9:1. The engines had a Normal Power rating of 1,500 horsepower at 2,400 r.p.m., and 1,700 horsepower at 2,600 r.p.m. for takeoff, burning 100-octane gasoline. 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).

“On a low level training mission early in 1942 B-25 40-2297 would be airplane number 14 for the Doolittle Raid on Tokyo — This image was taken before the modification to the troublesome ventral turret. Pilot Major J.A. Hilger, Co-Pilot 2nd Lt. Jack A. Sims, Navigator 2nd Lt. James H. Macie, Jr., Bombardier S/Sgt. Jacob Eierman, Engineer/Gunner S/Sgt. Edwin V. Bain” —HISTORYNET

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 (1,361 kilograms) bomb load 2,000 miles (3,219 kilometers). Defensive armament consisted of a single Browning M2 .30-caliber machine gun mounted in the nose, two Browning M2 .50-caliber machine guns in a power dorsal turret, and two more .50s in a retractable ventral turret. (The lower turrets were removed from all of the Doolittle B-25s.)

North American Aviation, Inc., built 9,816 B-25s at Inglewood, California, and Kansas City, Kansas. 120 of these were B-25Bs.

North American Aviation B-25 Mitchell medium bombers being assembled at the Kansas City bomber plant, October 1942. (Alfred T. Palmer, Office of War Information)

© 2017, Bryan R. Swopes

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