B25

B25, B-25 or B.25 may refer to:

North America

North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere. It can also be considered a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.

North America covers an area of about 24,709,000 square kilometers (9,540,000 square miles), about 16.5% of the earth's land area and about 4.8% of its total surface. North America is the third largest continent by area, following Asia and Africa, and the fourth by population after Asia, Africa, and Europe.

In 2013, its population was estimated at nearly 565 million people in 23 independent states, or about 7.5% of the world's population, if nearby islands (most notably the Caribbean) are included.

North America was reached by its first human populations during the last glacial period, via crossing the Bering land bridge. The so-called Paleo-Indian period is taken to have lasted until about 10,000 years ago (the beginning of the Archaic or Meso-Indian period). The Classic stage spans roughly the 6th to 13th centuries. The Pre-Columbian era ended with the arrival of European settlers during the Age of Discovery and the Early Modern period. Present-day cultural and ethnic patterns reflect different kind of interactions between European colonists, indigenous peoples, African slaves and their descendants. European influences are strongest in the northern parts of the continent while indigenous and African influences are relatively stronger in the south. Because of the history of colonialism, most North Americans speak English, Spanish or French and societies and states commonly reflect Western traditions.

North American B-25 Mitchell

The North American B-25 Mitchell is an American twin-engine, medium bomber manufactured by North American Aviation (NAA). It was named in honor of Major General William "Billy" Mitchell, a pioneer of U.S. military aviation. Used by many Allied air forces, the B-25 served in every theater of World War II and after the war ended many remained in service, operating across four decades. Produced in numerous variants, nearly 10,000 Mitchells rolled from NAA factories. These included a few limited models, such as the United States Marine Corps' PBJ-1 patrol bomber and the United States Army Air Forces' F-10 reconnaissance aircraft and AT-24 trainers.

Design and development

The Air Corps issued a circular (Number 38-385) in March 1938 describing the performance they required from the next bombers — a payload of 1,200 lb (540 kg) with a range of 1,200 mi (1,900 km) at more than 200 mph (320 km/h). Those performance specifications led NAA to submit their NA-40 design. The NA-40 had benefited from the North American XB-21 (NA-39) of 1936 which was the company's partly-successful design for an earlier medium bomber that had been initially accepted and ordered but then cancelled. However, the company's experience from the XB-21 contributed to the design and development of the NA-40. The single NA-40 built flew first at the end of January 1939. It went through several modifications to correct problems. These improvements included fitting 1,600 hp Wright R-2600 "Double Cyclone" radial engines, in March 1939 which solved the lack of power.

Grimes Field

Grimes Field (FAA LID: I74) is a city-owned public-use airport located one nautical mile (1.85 km) north of the central business district of Urbana, a city in Champaign County, Ohio, United States. Named for Warren G. Grimes, it is also known as Urbana Municipal Airport and it serves general aviation traffic.

The airport is home to the Champaign Aviation Museum. It also houses a project to rebuild a World War II era B-17 Medium Bomber called the Champaign Lady. The B-17 Project website shows the progress and has a live web camera in the hangar where the aircraft is stored. Volunteers work on it Monday through Saturday. As of 01Feb2015 the airport manager is Louis M Driever.

Facilities and aircraft

Grimes Field covers an area of 329 acres (133 ha) at an elevation of 1,068 feet (326 m) above mean sea level. It has one runway designated 2/20 with an asphalt surface measuring 4,400 by 100 feet (1,341 x 30 m).

For the 12-month period ending June 7, 2007, the airport had 23,480 aircraft operations, an average of 64 per day: 96% general aviation, 2% military and 2% air taxi, At that time there were 36 aircraft based at this airport: 72% single-engine, 11% multi-engine, 6% helicopter and 11% ultralight.

Medium bomber

A medium bomber is a military bomber aircraft designed to operate with medium-sized bombloads over medium range distances; the name serves to distinguish this type from larger heavy bombers and smaller light bombers.

The term was used prior to and during World War II, based on available parameters of engine and aeronautical technology for bomber aircraft designs at that time. After the war, medium bombers were replaced in world air forces by more advanced and capable aircraft.

History

In the early 1930s many air forces were looking to modernize their existing bomber aircraft fleets, which frequently consisted of older biplanes. The new designs were typically twin-engined monoplanes, often of all-metal construction, and optimized for high enough performance and speed to help evade rapidly evolving fighter aircraft designs of the time. Some of these bombers, such as the Heinkel He 111, Junkers Ju 86, Savoia-Marchetti SM.79, Douglas B-18, and Armstrong Whitworth Whitley were developed from or in conjunction with existing airliners or transport aircraft.