Georgy Vasiliev, an engineer from Kazan, has patented an unusual power plant for a stratospheric aircraft with a lifting gas envelope. The system combines a closed-cycle engine, a thermoacoustic generator, and a lifting gas heating circuit.

The key feature of the design is that a single heat source performs several tasks at once. First, hot gas transfers energy to a thermoacoustic module, which generates electricity. Then, the flow can be directed to the main engine's heat exchanger, where the working fluid is heated and thrust is created.

After this, the heat is not wasted. The engine's condenser and the generator's cold heat exchanger are connected to a common secondary circuit, which transfers thermal energy to the lifting gas of the envelope. This allows compensating for its cooling and maintaining lift.

At the same time, the main engine can be completely stopped. In this mode, hot gas flows through a bypass channel, and the thermoacoustic generator continues to generate electricity for onboard equipment. That is, thrust is no longer mandatory for the platform's continuous power supply.

The system is designed to operate at an altitude of 15–20 km, where the air is rarefied and solar energy depends on the time of day and weather.

A few days ago, the designer also presented another patent that specifies the design features of the stratostat. This apparatus can be equipped with a docking unit, allowing for fuel replenishment and extremely long airtime, operating as a quasi-satellite.