During this period, people began to try hybrid jet engines. The traditional piston engine drives the fan to compress air and ignite the gas propulsion in the back space. For example, KOANDA/KOOC-0/9/KOOC-0/0, Campini Caproni CC.2, Jin-/KOOC-0//KOOC-0/engines used by Japanese Kamikaze special forces. The attempt of this era is called automobile injection. Although this kind of engine is simple in structure, it has heavy weight, insufficient thrust and poor practicability.
The key to solve the problem is to drive the compressor with a gas-driven turbine, which can save the redundant piston engine in the hot jet engine and provide greater thrust. The idea is similar to that of a gas turbine. 1903 Norwegian &; Guidice Arryn of AElig invented the gas turbine. But this technology can not be applied to jet engines, because the materials at that time could not produce such engines, and there are still many problems in safe and continuous operation.
Other solutions are also under way. 19 15, Albert Fono of Austria-Hungary designed a device to increase the range of artillery shells through gas and compressed air. This device compresses and ignites the airflow when the projectile flies through the variable cross-section inlet at high speed, thus providing thrust. The Austro-Hungarian army finally failed to adopt its design, so he registered the patent of supersonic ramjet in Germany at 1928 and got it at 1932. Ramjet engine was born.
192 1 year, French Maxim Guillaume obtained the first patent of jet engine. His design is similar to that of an axial-flow jet engine. 1923, a report published by the American National Bureau of Standards expressed doubts about the role of jet engines. The report thinks that jet engines flying at low altitude at that time had no economic value, and even points out that any possible jet propeller at present has no practical value, even for military purposes.
1928, Frank Whittle of the Royal Air Force Academy in Cromwell, England, proposed a new jet engine design. 1930 10, whittle submitted the design patent of jet engine, and obtained the patent in 1932. Whittle's design is to install a two-stage axial compressor in front of a large centrifugal compressor, which is driven by a turbine. Later, whittle removed the front axial compressor and used a larger centrifugal compressor. This engine was tested in 1937, but it failed because of oil leakage. Whittle's design was shelved because the British government was not interested in it.
At the same time, Hans von Ohan of Germany is designing completely independently in Germany. At first, Aoan's engine was driven by electricity, and his purpose was only to demonstrate the feasibility of this engine. Aoan later joined Henkel, which was looking for a jet engine design and tested a new engine. The new engine initially used hydrogen as fuel, and later switched to ordinary aviation fuel. He can provide 5kN thrust. 1939 On August 27th, the pilot Erich Warsitz took off from Rostock-Marineh airport with an Aoan jet engine at He- 178. This is the first jet plane in human history.
British jet fighters equipped with centrifugal jet engines and German jet fighters equipped with rockets and axial jet engines both participated in the fighting in the late World War II. German jet fighters with advanced performance have achieved excellent results. Prompted the aircraft to quickly turn to the jet age in the later era.