The Soviet Union never had a shortage of talented engineers and designers. Archival documents and rare publications only confirm that many promising technical solutions never went beyond prototypes. The reasons varied, but the result was often the same — the project remained on paper.
One such almost forgotten development was an engine with a variable compression ratio, created in Georgia by engineer and inventor Vakhtang Vasilyevich Makhaldiani.
Tbilisi Engineering School
The work was carried out in Tbilisi, at the Georgian Agricultural Institute, where Makhaldiani taught and conducted research activities since 1932. Over several years, he went all the way from preliminary sketches to accurate calculations and the design of an additional unit for one of the most common engines of that time — the GAZ-MM engine.
The key idea was the variable geometry of the combustion chamber. A movable dome of the chamber was implemented in the cylinder head. Its position could be adjusted, thereby changing the volume of the combustion chamber and the compression ratio of the engine. Similar theoretical concepts were also discussed among American engine builders, but across the ocean, it never even came to the manufacture of an experimental sample.
Unfortunately, photographs of the engine itself have not survived to this day.
It is noteworthy that in our time, Infiniti engineers, solving a similar problem, took a different path — changing the crank arm of the crankshaft. This method is considered technically complex and potentially less reliable. Makhaldiani proposed his own original control system, effectively developing a new type of engine.
Working Prototype
By 1948, the project had moved from theory to practice: a real functioning prototype was built. The experimental engine was created in very cramped conditions — on primitive equipment and with an acute shortage of materials. Nevertheless, the installation turned out to be fully operational.
It was not about a short-term start-up, but about full-fledged operation within the framework of testing. The engine was tested for fuel consumption, operation under load, durability, and reliability of key components. The results were impressive: gasoline consumption decreased by approximately 20%.
Recognition Without Continuation
After the first successes, Makhaldiani, together with his colleagues, turned to Academician Evgeny Alekseevich Chudakov — the head of the Institute of Mechanical Engineering of the Academy of Sciences of the USSR. In July 1948, official tests were conducted at the institute, which confirmed the presence of an economic effect.
Various reports featured different values, but the average fuel economy was from 18 to 26%. The project received the support of the Secretary of the Central Committee of the Communist Party of Georgia, Kandid Charkviani, who directly appealed to the Minister of the Automotive Industry, S. A. Akopov.
The Director of the Georgian Agricultural Institute, Urushadze, went even further and sent a letter to Lavrentiy Pavlovich Beria. This was followed by a series of meetings with representatives of NAMI, specialized research institutes, metropolitan professors, and enterprise managers. However, this activity did not receive practical continuation.
How the Project "Drowned" in the System
The Moscow scientific community did not deny the originality and operability of the engine, but the promotion of the development was constantly postponed. The answers from the capital were formal: the topic is included in the research plan for the next five-year period. Proposals for joint work were systematically rejected.
Most likely, the appeal to Beria never reached his personal consideration. During that period, he was focused on strategic projects, and such letters were most likely reviewed by assistants or redirected to specialized institutes.
There was no complete ignoring — it would have been dangerous for the performers. Therefore, in 1949, the materials were submitted to the Board of the Ministry of the Automotive Industry. There, leading experts made a formal conclusion: the unit was recognized as too complex for mass production. On this basis, further development of the topic was considered impractical.
The correspondence continued for several more years, after which it finally ceased. Vakhtang Vasilyevich Makhaldiani himself did not abandon research: he continued to study ways to change the compression ratio of internal combustion engines and subsequently wrote a book dedicated to his project.
