The engines are built with stealth technology from inconspicuous fighters and leave inversion marks that reduce stealth. The American publication Popular Mechanics talks about the problem of stealth planes.

In 2021, it is recorded that a secret RQ-180 unmanned aerial vehicle was detected in the USA and attention was paid to the reversal trace.

“This cloud-like reversal trail, a water vapor trail created when an airplane flies at high altitude, led them straight to the mysterious plane, like a long white arrow that reads ‘I’m here’.”is publishing.

An inversion track is formed after mixing cold air with steam from the exhaust gases of a condensed aircraft engine. At a certain altitude, the plane can fly without a trace. “Theoretically, there will always be drier air a few thousand feet above you.”said Adam Durant, CEO of SATAVIA, which makes inversion monitoring simulation software.

In 1961, the USA created a system for injecting chlorosulfonic acid into the exhaust gases of B-47 Stratojet bomber engines. This made it possible to create an inversion trace from inconspicuous particles. The system turned out to be effective, but the weight of the equipment was 180 kilograms, which reduced the bomb load of the aircraft. In addition, the plane was carrying a chemical that reduced the amount of fuel carried around.