World War I enlisted rockets once again for military purposes. French pilots rigged rockets to the wing struts of their airplanes and aimed them at enemy observation balloons filled with highly inflammable hydrogen.

Abe Silverstein, Associate Director of the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory, provides a personal tour of the new 10- by 10-Foot Supersonic Wind Tunnel for US Senator George Bender (hat in hand) and General Lemuel Shepherd. Shepherd was Commandant of the Marine Corps and had served in World War I, World War II, and the Korean War. The general was accompanied by Admiral Herbert Leary, in dark uniform. Bender was a Republican Senator from Ohio. Behind Bender is President of the Cleveland Chamber of Commerce Curtis Smith. NACA Lewis managers Eugene Manganiello and Wilson Hunter assist with the tour. Abe Silverstein oversaw all research at the laboratory. Upon taking his post in 1952 he reorganized the research staff and began shifting the focus away from airbreathing aircraft engines to new fields such as high energy fuels, electric propulsion, and nuclear power and propulsion. He was an early advocate of the NACA’s involvement in the space program and crucial to the founding of National Aeronautics and Space Administration in 1958. Silverstein began his career helping design and conduct research in the Full Scale Tunnel in 1929 at the Langley Memorial Aeronautical Laboratory. Silverstein advocated a series of increasingly large supersonic wind tunnels after the war, culminating in the 10- by 10.

A Wright Aeronautical R–2600 Cyclone piston engine installed in the Engine Propeller Research Building, or Prop House, at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory. The R–2600 was among the most powerful engines that emerged during World War II. The engine, which was developed for commercial applications in 1939, was used to power the North American B–25 bomber and several other midsize military aircraft. The higher altitudes required by the military caused problems with the engine's cooling and fuel systems. The military requested that the Aircraft Engine Research Laboratory analyze the performance of the R–2600, improve its cooling system, and reduce engine knock. The NACA researchers subjected the engine to numerous tests in its Prop House. The R–2600 was the subject of the laboratory's first technical report, which was written by members of the Fuels and Lubricants Division. The Prop House contained soundproof test cells in which piston engines and propellers were mounted and operated at high powers. Electrically driven fans drew air through ducts to create a stream of cooling air over the engines. Researchers tested the performance of fuels, turbochargers, water-injection and cooling systems here during World War II. The facility was also investigated a captured German V–I buzz bomb during the war.

General Henry “Hap” Arnold, Commander of the US Army Air Forces during World War II, addresses the staff at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory on November 9, 1944. Arnold told the employees assembled in the hangar, “You’ve got a dual task. You’ve got a job ahead of you to keep the army and the navy air forces equipped with the finest equipment that you can for this war. You also have the job of looking forward into the future and starting now those developments, those experiments, that are going to keep us in our present situation—ahead of the world in the air. And that is quite a large order, and I leave it right in your laps.” Arnold served on the NACA’s Executive Committee in Washington from 1938 to 1944 and had been a strong advocate for the creation of the new engine research facility in Cleveland. Arnold believed in continual research and development. He pressed the nation’s aviation leaders to pursue the new jet engine technology, while simultaneously pushing to increase the performance of the nation’s largest piston engine for the B–29 Superfortress program. The general’s hectic wartime agenda limited his visit to the Cleveland laboratory to just a few hours, but he toured several of the NACA’s new test facilities including the Static Jet Propulsion Laboratory, the Icing Research Tunnel, and a B–24 Liberator in the hangar.

A Consolidated B-25M Liberator modified for icing research by the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. NACA Lewis performed a limited amount of icing research during World War II, but the program expanded significantly in 1946. The accumulation of ice on aircraft was a continual problem. The ice formations could result in extra weight, aerodynamic penalties, and blockage engine inlets. Although the Lewis icing researchers utilized numerous aircraft, the program’s two workhorses were the B-24M Liberator, seen here, and a North American XB-25E Mitchell. The Consolidated Aircraft Company created the four-engine bomber in the early 1940s. During World War II the bomber was employed on long-duration bombing missions in both Europe and the Pacific. Production of the B-24M version did not begin until October 1944 with the end of the war in Europe approaching. This resulted in scores of unneeded bombers when hostilities ended. This B-24M arrived at the NACA Lewis laboratory in November 1945. At Lewis the B-24M was repeatedly modified to study ice accretion on aircraft components. Researchers analyzed different anti-icing and deicing strategies and gathered statistical ice measurement data. The B-24M was also used to study ice buildup on jet engines. A General Electric I-16 engine was installed in the aircraft’s waist compartment with an air scoop on the top of the aircraft to duct air to the engine. Water spray nozzles inside the aircraft were employed to simulate icing conditions at the turbojet’s inlet.

A General Electric TG-180 turbojet installed in the Altitude Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. In 1943 the military asked General Electric to develop an axial-flow jet engine which became the TG-180. The military understood that the TG-180 would not be ready during World War II but recognized the axial-flow compressor’s long-term potential. Although the engine was bench tested in April 1944, it was not flight tested until February 1946. The TG-180 was brought to the Altitude Wind Tunnel in 1945 for a series of investigations. The studies, which continued intermittently into 1948, analyzed an array of performance issues. NACA modifications steadily improved the TG-180’s performance, including the first successful use of an afterburner. The Lewis researchers studied a 29-inch diameter afterburner over a range of altitude conditions using several different types of flameholders and fuel systems. Lewis researchers concluded that a three-stage flameholder with its largest stage upstream was the best burner configuration. Although the TG-180 (also known as the J35) was not the breakthrough engine that the military had hoped for, it did power the Douglas D-558-I Skystreak to a world speed record on August 20, 1947. The engines were also used on the Republic F-84 Thunderjet and the Northrup F-89 Scorpion.

A mechanic works on a General Electric I-40 turbojet at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The military selected General Electric’s West Lynn facility in 1941 to secretly replicate the centrifugal turbojet engine designed by British engineer Frank Whittle. General Electric’s first attempt, the I-A, was fraught with problems. The design was improved somewhat with the subsequent I-16 engine. It was not until the engine's next reincarnation as the I-40 in 1943 that General Electric’s efforts paid off. The 4000-pound thrust I-40 was incorporated into the Lockheed Shooting Star airframe and successfully flown in June 1944. The Shooting Star became the US’s first successful jet aircraft and the first US aircraft to reach 500 miles per hour. The NACA’s Lewis Flight Propulsion Laboratory studied all of General Electric’s centrifugal turbojets both during World War II and afterwards. The entire Shooting Star aircraft was investigated in the Altitude Wind Tunnel during 1945. The researchers studied the engine compressor performance, thrust augmentation using a water injection, and compared different fuel blends in a single combustor. The mechanic in this photograph is inserting a combustion liner into one of the 14 combustor cans. The compressor, which is not yet installed in this photograph, pushed high pressure air into these combustors. There the air mixed with the fuel and was heated. The hot air was then forced through a rotating turbine that powered the engine before being expelled out the nozzle to produce thrust.

The National Advisory Committee for Aeronautics (NACA) Subcommittee on Combustion holds a meeting at Lewis Flight Propulsion Laboratory in Cleveland, Ohio. The NACA was managed by committees that included members of their own staff along with representatives from industry, the military, other government agencies, and universities. The 17-person Executive Committee was the NACA’s primary administrative body. They met several times a year at the NACA headquarters office in Washington DC to discuss broad issues confronting the US aeronautical community. Jerome Hunsaker, head of the Department of Aeronautical Engineering at the Massachusetts Institute of Technology, served as the NACA chairman from 1941 to 1956. George Lewis was not a member of the Executive Committee but served a key role as the NACA’s Director of Aeronautical Research. The NACA’s organizational chart also included 11 technical committees, several of which had specialized subcommittees. There were over 100 different subcommittees between World War I and 1958. The number of active subcommittees varied over the years. Most existed only for a few years, but some continued for over a decade. The subcommittees met three or four times per year, often at the laboratory most closely associated with the area of research. A team of laboratory researchers presented briefings on their recent activities and plans for the future. The Subcommittee on Combustion existed from 1945 to the NACA’s demise in 1958.