The contrails or defractory trails left by airplanes in the sky are a result of a complex polynomial involving several factors. First, clouds form when the temperature is extremely low and the humidity reaches 100 percent. Commercial airplanes fly in the highest layer of the troposphere, where temperatures are around -56°C.
Secondly, the engines used by airplanes generate thrust force through combustion, which creates water vapor and hot combustion gases. The water vapor condenses and creates the white grooves that we see on airplanes. Additionally, as the gas exits the engine, it expands and also contributes to the formation of contrails.
The term “contrail” was first coined by Anglo-Saxons, who combined “condensation” and “trail” to describe these white grooves in the sky. However, not all airplanes leave a wake behind them. The efficiency of a turbojet is measured by its ability to convert chemical energy into work done by its engines. Interestingly, contrails can be used to predict weather conditions as they can indicate changes in atmospheric pressure and temperature.
During air shows, polychrome grooves or colored contrails are sometimes created by mixing dyes and releasing them at just the right moment. These are not true condensation trails but rather an artful display put on for spectators. Finally, there is another type of contrail that occurs when an airplane exceeds its speed of sound: Prandtl-Glauert condensation clouds. These clouds take on the shape of a disk or cone and form as a result of a sudden drop in air pressure caused by high speeds.
Overall, understanding how contrails form is crucial for predicting weather conditions and optimizing aircraft performance during flight shows or any other aviation event.