The Curtiss A-12 Shrike was the United States Army Air Corps' second monoplane ground-attack aircraft, and its main attack aircraft through most of the 1930s. It was based on the A-8, but had a radial engine instead of the A-8's inline, water-cooled engine, as well as other changes.
A triplane is a fixed-wing aircraft equipped with three vertically stacked wing planes. Tailplanes and canard foreplanes are not normally included in this count, although they occasionally are.
The Caproni Ca.4 was an Italian heavy bomber of the World War I era.
The North American O-47 is an American observation fixed-wing aircraft monoplane designed in the mid-1930s and used by the United States Army Air Corps during the Second World War. It has a low-wing configuration, retractable landing gear, and a three-blade propeller.
The Curtiss A-18Model 76A Shrike II was a 1930s United States twin-engine ground-attack aircraft. It was the production test version of that company's A-14 Shrike.
The Boeing XP-9 was the first monoplane fighter aircraft produced by the United States aircraft manufacturing company Boeing. It incorporated sophisticated structural refinements that were influential in later Boeing designs. The sole prototype exhibited unsatisfactory characteristics with its lack of pilot visibility directly leading to its cancellation.
The Boeing F2B was a biplane fighter aircraft of the United States Navy in the 1920s, familiar to aviation enthusiasts of the era as the craft of the Three Sea Hawks aerobatic flying team, famous for its tied-together formation flying.
The Boeing F3B was a biplane fighter and fighter bomber that served with the United States Navy from 1928 into the early 1930s.
The Wittemann-Lewis NBL-1 "Barling Bomber" was an experimental long-range, heavy bomber built for the United States Army Air Service in the early 1920s. Although unsuccessful, it was an early attempt at creating a strategic bomber.
The Tarrant Tabor was a British triplane bomber designed towards the end of the First World War and was briefly the world's largest aircraft. It crashed, with fatalities, on its first flight.
The Ilyushin Il-20 was a Soviet prototype for a heavily armored ground-attack aircraft to replace the Ilyushin Il-10. It featured a number of innovative concepts including a cockpit mounted on top of the engine, directly behind the propeller, and wing-mounted autocannon that could be adjusted on the ground to fire level or depressed 23° to allow the aircraft to strafe ground targets while remaining in level flight. However it was slower than the Il-10, and its M-47 engine was problematic in flight tests in 1948–49. It was not placed into production. The test pilots called the aircraft the Gorbach (Hunchback).
The Gotha G.IV was a heavy bomber used by the Luftstreitkräfte during World War I. It was the first mass-produced relatively large airplane.
The Ilyushin Il-40 was a two-seat Soviet jet-engined armored ground-attack aircraft. The first prototype flew in 1953 and was very successful except when it fired its guns, as their combustion gasses disturbed the airflow into the engines and caused them to flameout or hiccup. Remedying this problem took over a year and involved the radical change of moving the engine air intakes all the way to the very front of the aircraft and repositioning the guns from the tip of the nose to the bottom of the fuselage, just behind the nosewheel. The aircraft, now resembling a double-barreled shotgun from the front, was ordered into production in 1955. Only five production aircraft had been completed before the entire program was canceled in early 1956 when the VVS discarded its close air-support doctrine in favor of tactical nuclear weapons on the battlefield.
The Blackburn Triplane was a single-engine pusher single-seater, designed specifically to attack Zeppelins. It flew in 1917, but was not successful.
The Royal Aircraft Factory F.E.4 was a twin-engine biplane aircraft built by the Royal Aircraft Factory in 1916. Intended as a cannon armed ground-attack aircraft, it was unsuccessful, only two being built.
The Armstrong Whitworth F.K.5 and F.K.6 were experimental triplanes built as escort fighters by Armstrong Whitworth during the First World War. They carried two gunners in nacelles mounted on the centre wing. One example of each type was built, with no further development or production following.
The Schütte-Lanz G.I was a large, twin engine, pusher configuration, experimental biplane built in Germany early in World War I. Only one was completed.
The Lloyd 40.08 Luftkreuzer was a three engine triplane bomber type built during World War I. The design was proven to be ineffective and development did not proceed past the prototype stage.
The Caproni Ca.66 was an Italian night bomber designed to reequip the post-World War I Italian Air Force. Only two examples of the four-engined biplane were built.
The Henri Farman HF.35 was a large 3-seat biplane designed and built in France by Henri Farman during 1915.
