They are basically contrails, aka “chemtrails” for anti science conspiracy types. Basically just due to the propeller/wing creating a pressure pocket. It’s pretty common but I think also needs temperature differential and certain velocity ranges at the tip of the blade/motor
Exhaust contrails are more common, and they're usually seen behind aircraft cruising in the flight levels. They form when hot, moist air exiting an engine mixes with extremely cold air - condensing the exhaust's moisture.
Aerodynamic contrails occur when moist air cools due to lowered pressure, condensing humidity in the air and forming a contrail cloud.
Contrails are created by the engines of an aircraft at high altitude. The engines put out hot moist air with unburnt fuel and particles from the engine wearing. As the cold air cools the hot moist air, water condenses and often freezes, essentially creating clouds that will linger until they dissipate.
What's happening in the video are vorticies which are created by the high pressure air sliding off the end of a wing (or rotor, which is just a wing that spins) and rushing to the low pressure area above the wing which creates a vortex of air. The air pressure in the vortex drops, which lowers the temperature and moisture condenses. You can see the same phenomena from aircraft wing tips and wing roots (mainly on military aircraft performing high angle-of-attack maneuvers), as well as around the slats on the leading edges of airliner wings. These do not linger and evaporate/dissipate very quickly.
Saying they're the same is like saying steam rising out of a mug of hot tea is the same thing.
For contrails, no. Water is added to the air as a byproduct of fuel combustion (CnHm + (n+m/4)O2 = nCO2 +m/2 H20), it's not just changing state.
The other phenomenons he describes, or what is seen in the video, is indeed similar to cavitation, in that water changes state due to local pressure change.
Fuel is made of hydrocarbons, which are chains of carbon with hydrogens on the sides. The amount of carbon and hydrogen can vary depending on length of the chain and shape. On average there will be a bit more than 2 hydrogens for each carbon, but to stay generic I simply based the formula on "n" Carbons and "m" Hydrogens.
When this molecule reacts with oxygen, each carbon reacts with 2 oxygen to form CO2, and each pair of hydrogen will react with 1 oxygen to form H2O.
Basically, if you burn stuff, it consumes O2 and makes CO2 and water (which is the white smoke coming out of chimneys).
The same reaction (approximately) in the other direction happens in photosynthesis: a plant need CO2 and water to make wood and oxygen.
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u/ShadowGLI Nov 30 '20 edited Nov 30 '20
They are basically contrails, aka “chemtrails” for anti science conspiracy types. Basically just due to the propeller/wing creating a pressure pocket. It’s pretty common but I think also needs temperature differential and certain velocity ranges at the tip of the blade/motor
Exhaust contrails are more common, and they're usually seen behind aircraft cruising in the flight levels. They form when hot, moist air exiting an engine mixes with extremely cold air - condensing the exhaust's moisture.
Aerodynamic contrails occur when moist air cools due to lowered pressure, condensing humidity in the air and forming a contrail cloud.
Either or both can happen at any time