A.G.UFIMTSEV AVIATION ENGINE

Anatoly Georgievich Ufimtsev is one of the talented Russian inventors and designers, «poet in the field of scientific technique» as he was called by A.M.Gorky.

A.G.Ufimtsev was born in 1880 in Kursk. In the junior forms of the non-classical secondary school he started his activity as inventor and dreamed about two things — to design and to build an aircraft and to make a wind turbine over his house.

The first idea could not come true at that time due to the lack of sufficiently light and powerful engine. In 1905 Ufimtsev started to design and to build an original birotary aviation engine with crankshaft and cylinders revolving in opposite directions.

The principle of birotativeness assured, first, more intensive cylinder cooling both in flight and on the ground, and, second, the doubled number of revolutions and as a consequence the increase in power. This allowed to cut in half the number of cylinders and to quarter the centrifugal forces throwing the oil out from the cyl­inders.

A.G.Ufimtsev first built in his workshop in Kursk a two-cylinder two-stroke aviation birotary engine with air cooling. One two-bladed propeller was fastened on the crankshaft and the other on the cylinder heads. The power of the engine according to the designer estimation was 15 — 20 h.p. with its mass together with propellers about 40 kg. The engine was mounted on the aircraft «Spheroplane Number 1» designed by Ufimtsev. It made some ground runs during the tests but never took off.

In 1909 Ufimtsev designed a four-cylinder birotary engine with mixture ignition at high compression in cyl­inder 90 mm in diameter and a piston stroke of 120 mm. This invention of A.G.Ufimtsev was granted patent.

The experts of Chief Engineering Department gave negative reference on the project. According to their opinion, it was impossible to start an engine with com­pressed air. (The further development of aviation con­firmed the expendience of the air starting of an engine.)

Nevertheless A.G. Ufimtsev did not give up the in­tention to turn his idea in practice. The four-cylinder engine with self-ignition did not satisfy him, and in a new project he used electric system of air-fuel mixture ignition at the less compression ratio.

He received a small credit from private persons, mortgaged his house and collected all cash in hands to build a six-cylinder birotary engine with a cylinder di­ameter of 80 mm, a piston stroke of 110 mm and a rotation frequency of 1000 r.p.m. Mass of the engine 50 kg, the design power 40 h.p. **

A.G.Ufimtsev mounted this engine on the aircraft «Spheroplane-2» designed and built by him in 1910. During the tests the aircraft did not take off due to the forward centre-of-gravity position. Moreover, after some ground runs the engine stopped due to the defects in the system of forced lubrication.

In 1912 A.G.Ufimtsev designed a new six-cylinder two-stroke birotary engine with improved cylinders blow­ing. The shortcomings of the previous engines were re­paired, and the parameters and construction of the main units were considerably changed. The diameter of the cylinders was 100 mm, the piston stroke was 120 mm, the rotation frequency of the shaft and cylinders was 1000 r.p.m., the design power was in the range of 65— 70 h.p. with a mass of 58 kg.

The engine was built at Bryansk steam locomotive building works and got name ADU-4 (Ufimtsev aviation engine, the fourth variant). Its tests and development were not finished. The production of the engine was rejected by the works. A.G.Ufimtsev had to abandon his activity in aviation due to the lack of support because poor experimental and production basis did not allow him to create a reliable birotary engine. He did not receive any support from the state, too. Later A.G.Ufimt­sev designed and built the engines for agricultural ma­chines and designed the wind turbines.

In 1912 the engine ADU-4 was demonstrated at the Second International Airnautical Exhibition in Moscow. For interesting idea A.G.Ufimtsev was awarded Grand Silver Medal (the president of the juree was professor N.E.Zhukovsky).

Since 1960 ADU-4 is in the Air Force Museum and invariably draws attention among the visitors.

G.A.Davydov

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