Boeing developed the B-29 Superfortress as a high-altitude daylight bomber for World War II. Although physically about the same size as its predecessors, the B-17 and B-24, the B-29 was much more refined in design. It had nearly twice the power and weight as the previous bombers, yet it was significantly faster and could reach higher altitudes. Other innovations included a pressurized cabin, fire control system, and remote-controlled machine-gun turrets.
The first B-29s were in the air in 1943, but they suffered a variety of problems, largely stemming from the military’s unprecedented rush to develop the aircraft. The four powerful Wright R-3350 engines posed significant problems during the war particularly at high altitudes. Thus military leaders cancelled the B-29’s high-altitude daytime missions and instituted low-altitude nighttime incendiary bombing missions.
The B-29A model, built exclusively at Boeing's Renton, Washington plant, featured an improved wing design and a four gun forward top turret. Boeing produced 1100 of the B-29A bombers before production stopped in May 1946. The Air Force used the B-29A extensively in the Korean War during the early 1950s, but retired it from combat afterwards.
Utilization at Glenn: The military flew a B-29A to Cleveland on June 22, 1944 to flight test NACA modifications to its Wright R-3350 engines. B-29 pilots had been reporting that their engines were over-heating and losing power at higher altitudes. NACA researchers studied the engines in the lab's Engine Research Building and Altitude Wind Tunnel. New methods of ducting the cooling air flow through the engine and injecting the fuel were developed. These modifications were successfully flight tested multiple times on the B-29A during in June and July 1944.
After the war, another the laboratory acquired another B-29. Between April 1946 and October 1948 it was used as a flying testbed for turbojet and ramjet engines. The engines were mounted under the fuselage and operated in flight conditions. Ramjet-powered missiles were also launched from the aircraft.
