Today in WW II: 11 May 1939 Japanese begin attempt to seize Mongolian land to the banks of the Khalkin Gol River at Nomonhan, clashing with Soviet troops. More 
11 May 1940 Belgian fortress Eben Emael, on the Meuse River, reputed to be the most formidable stronghold in the world, falls to German Army glider assault.
11 May 1940 Luxembourg falls to the German army.
11 May 1940 On the night of 11-12 May, 1940 the Royal Air Force [RAF] attacked Mönchengladbach, Germany, the first Allied air raid on Germany of WW II.
11 May 1943 American troops invade Attu in the Aleutian Islands, beginning campaign to expel occupying Japanese forces [11-29 May].
11 May 1944 Allied Fifth and Eighth Armies launch long-awaited offensive, finally capturing Cassino and breaking the German Gustav Line [night of 11-12 May].
Visit the Olive-Drab.com World War II Timeline for day-by-day events 1939-1945! See also WW2 Books.

North American Aviation O-47

North American Aviation developed the O-47 to replace the O-19 and O-38 observation biplanes. It was larger and heavier than most preceding observation aircraft and its crew of three sat in tandem under the long canopy. Windows in the deep belly overcame the obstacle that the wings presented to downward observation and photography. The design for the XO-47 prototype originated in 1934 with General Aviation, a subsidiary of North American Aviation, as the GA-15. The Air Corps ordered 174 O-47s in 1937-38, 93 of which were assigned to National Guard units. In 1938, the Army ordered 74 O-47Bs with a redesigned engine cowling for better cooling, a more powerful engine, and improved radio equipment.

North American Aviation O-47B Specifications

Span 46 ft. 4 in.
Length 33 ft. 3 in.
Height 13 ft. 9 in.
Engine Wright R-1820 of 1,060 hp.
Crew 3
Maximum speed 227 mph.
Cruising speed 200 mph.
Range 840 miles
Service Ceiling 24,100 ft.

The O-47B was armed with one fixed, forward-firing .30 cal. machine gun plus one flexible .30 cal. machine gun in rear cockpit.

North American O-47 U.S. Army Air Force photo, World War II
North American O-47 U.S. Army Air Force photo, World War II.

North American Aviation O-47B photographed at the National Museum of the United States Air Force, Wright-Patterson AFB, OH, August 2005.   The O-47B on display was acquired in 1978 from Mr. Loren L. Florey, Jr., Eden Prairie, Minnesota. It was restored in the markings of an O-47A of the 112th Observation Squadron (Ohio National Guard) by the 179th Consolidated Aircraft Maintenance Squadron, Ohio ANG, at Mansfield, Ohio. According to the Museum, it was serial number 39-112, C/N: 51-1025.  Other registrations were N73722, XB-YUW but is displayed as: 37-328.  Photo: Courtesy of Bob Pettit
North American Aviation O-47B photographed at the National Museum of the United States Air Force, Wright-Patterson AFB, OH, August 2005. The O-47B on display was acquired in 1978 from Mr. Loren L. Florey, Jr., Eden Prairie, Minnesota. It was restored in the markings of an O-47A of the 112th Observation Squadron (Ohio National Guard) by the 179th Consolidated Aircraft Maintenance Squadron, Ohio ANG, at Mansfield, Ohio. According to the Museum, it was serial number 39-112, C/N: 51-1025. Other registrations were N73722, XB-YUW but is displayed as: 37-328. Photo: Courtesy of Bob Pettit.

North American Aviation O-47B photographed at the National Museum of the United States Air Force, Wright-Patterson AFB, OH
North American Aviation O-47B photographed at the National Museum of the United States Air Force, Wright-Patterson AFB, OH. This is the same aircraft shown inside the Museum above.