AN/APQ-7 Airborne Radar


3 cm
30 miles
50 km
20' (6m) reversed dipole linear phased array
0.4 degrees
1100 lbs
500 kg

The AN/APQ-7 "Eagle" airborne bombing radar was a refinement of H2X complete with an impact predictor used in the B-29B Superfortress. It was a considerable improvement on the AN/APQ-13 used in the original Superfortress, which had lacked resolution. An invention of the Nobel Laureate physicist Luis Alvarez at the MIT Radiation Laboratory, "Eagle" achieved its remarkable resolution by using a large phased array radar antenna that took the form of a winglike radome beneath the aircraft fuselage. This gave sufficient resolution for the radar to pick out a single large building in an urban area. The radar included an impact predictor that could be set up for 11 different bomb types.

"Eagle" first saw operational use in May 1945,  and it might have revived the prospects of a true conventional precision bombing campaign against Japan had the war continued. However, it was difficult to use (requiring two men) and it could not match the precision of daylight optical bomb sights. Its large antenna was an insoluble source of drag, unsuitable for high-velocity bombing aircraft, and so its use was limited to the B-29.


"Development of Airborne Armament 1910-1961" (accessed 2014-3-13)
Goebel (2013-2-1; accessed 2014-3-12)
Tillman (2010)

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