(C) Daily Kos This story was originally published by Daily Kos and is unaltered. . . . . . . . . . . Air Force Museum: Interwar years memorabilia (photo diary) [1] ['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.', 'Backgroundurl Avatar_Large', 'Nickname', 'Joined', 'Created_At', 'Story Count', 'N_Stories', 'Comment Count', 'N_Comments', 'Popular Tags'] Date: 2023-01-27 Shown above is the Spokane Spokesman-Review Free-for-All Trophy. According to the Museum: Army Air Corps pilot Lt. Eugene C. Batton received the Spokane Spokesman-Review Trophy for winning the "Free-for-All Military Pursuit Ship Race" at the 1927 National Air Races sponsored by the city of Spokane, Wash. This race consisted of 10 laps around a 12-mile course, and it was called a "free-for-all" because all the competing Army, Navy and Marine Corps pilots took off at the same time. Shown above is a wing from Curtiss R-8 Racer. According to the display: “The metal surface is the radiator in which the engine’s coolant was circulated. This type of radiator reduced air resistance and increased the aircraft’s top speed about 15 mph.” Shown above is an aerial route flashing beacon. According to the Museum: The U.S. Army Air Service placed beacons like this one around airfields in the early 1920s. They were also stationed three miles apart along the established air mail routes, and at night, pilots could see their constant glow from 10 miles away. A switch automatically turned the light on at night or on overcast days and shut it off during daylight hours. Developed from a Swedish light used by the British Air Ministry on the London to Paris air route, this American Gas Accumulator Co. beacon used acetylene gas to produce 5,000-candlepower flashes 150 times a minute. Shown above is the Mark I Demolition Bomb first tested in 1921. According to the display: “Purportedly, the US Army Air Service removed this weapon from service in the mid-1920s because its destructive force was greater than needed to destroy any man-made target. Also, with the grounding of its last, obsolete Handley-Page 0/400 bomber from the World War I period, the Army Air Service no longer possessed an airplane that could carry a 4,300-lb bomb.” Shown above is O-38F wing section showing the construction techniques of the 1930s. According to the display: “The wing span consists of a three-ply, routed “I-beam” section of spruce. The “truss” style ribs consisted of spruce reinforced by mahogany veneer gussets. Where additional strength was necessary, such as on the leading edge of the wing, a mahogany veneer reinforced the fabric covering.” Shown above is the Gordon Bennett Balloon Trophy. Propellers As shown from left to right in photograph: Hinged-Blade Research Propeller This 10-foot experimental propeller was ground-tested at McCook Field for the U.S. Navy. Built by Paragon Engineers Inc., it was designed with hinged blades to permit it to adapt to changes in air pressure. Micarta Controllable Pitch Propeller This 9-foot propeller has "Bakelite Micarta" blades counterbalanced to permit the pitch to be changed in flight. Designed by McCook Field engineers for testing with the Wright-built 180-hp Hispana-Suiza engine, it was tested in 1922 at McCook Field but was not successful. Olmstead High Efficiency Propeller This unusual 9-foot propeller was designed in 1918 by Olmstead Laboratories and tested at McCook Field. It was intended for possible use on the Loening M-8 aircraft before the Air Service decided not to order the M-8 into production. Curtiss Reed Propeller Produced in the 1920s, this 10-foot aluminum-alloy propeller was unique because its blades were mechanically twisted during manufacture to provide the necessary angle for thrust. PW-8 aircraft with Curtiss D-12 engines and XO-1 aircraft with Liberty 12 engines used this kind of propeller. Shown above is an 8-foot, four-bladed propeller made in 1923. Shown above is a propeller designed and constructed in 1923 at McCook Field. It was modified for the Verville-Sperry R-3 Racer. Aerial Photography According to the Museum: After World War I, the U.S. Coast and Geodetic Survey asked for the U.S. Army Air Service's help in using aerial photographs for mapping, and tests conducted during the summer of 1919 proved the concept. In 1920 Brig. Gen. Billy Mitchell stated that the Army Air Service -- if properly organized -- could make an aerial survey of the entire country in three years. He advocated a single organization to coordinate those efforts, which matched his efforts to create a single air arm for the United States. Mitchell's hopes for a single organization were never fulfilled, but the Army Air Service did photographic work for many U.S. government agencies. In addition to taking aerial photographs for mapping, Army aircrews photographed a solar eclipse in January 1925. The government never provided sufficient funding to complete the aerial mapping of the United States, and after 1926, the Army Air Service performed aerial photography mainly in support of the War Department. Nevertheless, these mapping projects furthered the development of aerial reconnaissance, a critically important capability during World War II. Shown above is a T-3-1B5 mapping camera which used 5 cameras to cover a wider area. Bomb Sights According to the Museum: During World War I, the U.S. Army Air Service used bombsights provided by the Allies. The British-designed Wimperis had the reputation of only being "better than nothing at all." The French Michelin could not compensate for wind -- forcing the pilot to fly directly into or against the wind, which made the bomber an easy target for anti-aircraft gunners. Unless they flew very low over the target, a very dangerous thing to do, the bombardiers achieved only marginal results with the small bombs their airplanes could carry. Therefore, developing a high-altitude bombsight capable of correcting for crosswinds became an important project for the Army Air Service after the war. Hitting a target with a bomb from a fast-moving airplane is a difficult task. Even if traveling at 100 mph and only a few thousand feet above the ground, a bomb dropped just half a second too late could miss its target by hundreds of feet, and that error would be amplified by flying higher to avoid ground fire. In addition, the bombardier would have trouble seeing a small target tens of thousands of feet below, but simply using a telescope with crosshairs as a bombsight would not be enough. Any turbulence would bounce the airplane and throw off the aiming, and the bombsight needed internal stabilizers to counter the movement of the airplane. A bombardier had to use a complex formula that incorporated the trajectories of different size bombs with the effects of altitude, airspeed, true ground speed, cross winds and other variables such as hitting a moving battleship. Because doing all these computations in combat would be almost impossible, the Army Air Service needed a bombsight that could automatically perform all these calculations for the bombardier. In addition, the bombardier needed a simple method of transmitting minor course corrections to the pilot on the final approach to the target. The Army Air Service Engineering Division at McCook Field, Ohio, undertook the development of a new bombsight after WWI. Starting with the wartime Wimperis, designated the Mark I, the engineers incorporated a series of modifications that produced limited but inadequate improvements. Due to a lack of suitable Army bombsights, Gen. Billy Mitchell borrowed U.S. Navy Mark III-A bombsights to sink the Ostfriesland in 1921. The Engineering Division produced the D-1 bombsight in 1921. Based upon a sight designed by Georges Estoppey, the D-1 used a stopwatch to synchronize the aircraft speed with the true ground speed and used a pendulum for stabilization. In 1926 the Army adopted a later model of the Estoppey bombsight, the D-4. More heavily constructed than the D-1, the D-4 also incorporated an improved internal timing mechanism. When in perfect repair and under ideal conditions, the D-4 bombsight achieved good results up to 8,000 feet, but at higher altitudes, bombing errors became excessive. Meanwhile, the Engineering Division worked with the Sperry Gyroscope Co. to develop a bombsight designed by Alexander P. Seversky. Completed in 1924, the Sperry C-1 bombsight used a gyroscopic stabilizer. Another bombsight developed by the Army Air Service and built by Sperry in 1928, the Inglis L-1, synchronized the airspeed, altitude, true ground speed, and the bomb's ballistics. It also had a gyroscopic stabilizer and an automatic bomb release. The addition of pendulums or gyroscopes helped stabilize bombsights, but none of these bombsights achieved the accuracy Army aviators expected. Ironically, the solution came from merging a very accurate bombsight developed by Carl Norden for the Navy with an automatic pilot developed by Sperry for the Army. This arrangement gave the bombardier control over the aircraft during the final approach to the target. Although not as accurate as the Norden bombsight, the interwar bombsights proved superior to those used in WWI, and they gave planners the tools needed to develop the doctrine of high-altitude, daylight precision bombing adopted by the U.S. Army Air Corps in the 1930s. Shown above is the D-4 bombsight. More airplane memorabilia Air Force Museum: Flight clothing (photo diary) Air Force Museum: Aviator jackets (photo diary) Air Force Museum: World War II flight jackets (photo diary) Air Force Museum: World War II guns and bombs (photo diary) Air Force Museum: Early Years memorabilia (photo diary) Air Force Museum: Historic photos in the Early Years Gallery (photo diary) Air Force Museum: World War I memorabilia (photo diary) Air Force Museum: Korean War Memorabilia (photo diary) [END] --- [1] Url: https://www.dailykos.com/stories/2023/1/27/2149035/-Air-Force-Museum-Interwar-years-memorabilia-photo-diary Published and (C) by Daily Kos Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified. via Magical.Fish Gopher News Feeds: gopher://magical.fish/1/feeds/news/dailykos/