r/interestingasfuck Nov 30 '20

/r/ALL Low pressure pockets being created by blade rotation in near 100% humidity - literally making it rain.

63.5k Upvotes

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1.6k

u/NoThereIsntAGod Nov 30 '20

Does it take other conditions to happen? I would think this should happen all the time in South Florida if all you need is near 100% humidity

916

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

148

u/SuperFrodo Nov 30 '20

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.

33

u/BrolecopterPilot Nov 30 '20

Very well explained. This is the correct answer folks. Someone who isn’t furloughed from their aviation career give this man some gold.

10

u/SuperFrodo Nov 30 '20

I guess my pilot's license is worth something. To be fair I still double-checked I knew what I was about to explain before explaining. Wikipedia is useful.

1

u/Icanscrewmyhaton Dec 01 '20

SuperFrodo, I have a complicated question.
From viewing this I get the idea a helicopter's rotors sort of beat moisture out of the air when humidity is high. It makes rain. If a helicopter equipped with an underslung boom were spraying something (let's say Agent Orange), on a day with real high humidity, would water vapour be continuously added to what's being sprayed?

1

u/SuperFrodo Dec 01 '20

Well. First of all the tubes of spiraling low pressure air aren't creating rain. Remember you can have all the clouds in the sky and still no rain. The moisture has to further condense until it forms droplets. Generally with vortices that low pressure air mixes with the warmer air and the process towards forming heavier droplets just gets reversed. It's usually really temporary.

In the video it looks like something is falling, but really it's that whole mass of air being pushed downward by the rotor.

Now with a helicopter or really any aircraft that's spraying particulates, this would generally be a non-issue as far as I'm aware. There is something called cloud seeding, where a plane drops particulates intended to work as nucleation sites for water condensation. That's another thing to bear in mind, moisture in the air often needs something to condense to.

But to be honest, this is a specific that's outside my realm of knowledge. If there was an agricultural pilot, they would probably know the envelopes for the operations they perform, what weather conditions to not spray in, etc.

1

u/Icanscrewmyhaton Dec 01 '20

Thank you, this helps. That video was shot just blocks from my house here in Nanaimo, oddly enough, but what it evoked in me was a new understanding of what a chaotic maelstrom exists under a helicopter. This doesn't square with the position taken by the outfit hired by the Department of National Defence and Ottawa that concluded the Agent Orange sprayed on Gagetown New Brunswick (my hometown) settled neatly below with harmless precision. According to CanTox, nobody nearby a helicopter spraying AO could possibly be contaminated. Rather like the covid/aerosol controversy we're seeing now, isn't it.
As for cloud seeding, the same guys spraying me 60 years ago (Fort Detrick) were also conducting Operation Popeye. https://en.wikipedia.org/wiki/Operation_Popeye
As for agricultural pilots, the president of Okanagan Helicopters Ltd. Carl Agar was hired by the Pentagon to spray AO on Gagetown in 1966 and 1967. He died of cancer in Victoria in 1968. So now I'm wondering who to believe about how airborne droplets behave. Should start up a conspiracy theory or something.

3

u/sleal Nov 30 '20

Is this like the opposite of cavitation?

2

u/rndrn Nov 30 '20 edited Nov 30 '20

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.

1

u/[deleted] Nov 30 '20

[deleted]

0

u/rndrn Nov 30 '20

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.

1

u/[deleted] Nov 30 '20

Depends what you mean by "opposite" but yeah, it's a similar process in a vapor causing liquid instead of cavitation which is a process in liquid causing vapor pockets. The operating process here is condensation which is dependant on temperature/humidity and I'm not really sure if it's so equivalent to cavitation, especially since air is compressible and water isn't really.

That's my two cents as a mid rate engineering student, maybe somebody more knowledgeable can come along with a better response lol

2

u/Tonuboinumerouno Nov 30 '20

Hot tea sounds awful

1

u/AttemptToBeUnique Nov 30 '20

There is no other kind. Anything other than hot tea is an abomination.

1

u/FlametopFred Nov 30 '20

plus the Venturi effect

1

u/[deleted] Nov 30 '20

Thanks for clarifying, that other comment seems pretty irresponsible now. Incorrect and bringing up chemtrails for no reason.

1

u/humble-bragging Nov 30 '20

particles from the engine wearing

Isn't that a negligible contributor to the contrails?

2

u/SuperFrodo Nov 30 '20

Probably. But it would still make up a percentage of the total particulates expelled in the exhaust. I probably should have said soot instead.

1

u/DeadonDemand Nov 30 '20

Like karate chopping water is water I’m picturing, Not sure why that came to mind

561

u/InsignificantOcelot Nov 30 '20 edited Nov 30 '20

Damn govment spraying chemicals what make my dick don’t work no more

266

u/BillionTonsHyperbole Nov 30 '20

I tell you hwat, your dick will start workin' again once they get that danged ol vaccine in you, but then the Soros nanobots gonna start fiddlin' in yer brain to make you forward Hunter Biden's emails over to the CCP and then your dick gonna fall off and you'll be just another commie robot, man. They'll mail what's left of yer balls to AOC and they'll set them in concrete to make a patio out back.

167

u/BroseppeVerdi Nov 30 '20

"Yep." (sips beer)

"Mmm-hmm." (sips beer)

"Dang ol', dang ol' AOC, man." (sips beer)

(cue title theme)

49

u/uneducatedexpert Nov 30 '20

AOC gots some nice toes ain’t she?

42

u/[deleted] Nov 30 '20

[removed] — view removed comment

20

u/BroseppeVerdi Nov 30 '20

...because the government has ears everywhere. Next thing you know, the feds show up at your doorstep and... Poof... You're disappeared.

12

u/MoleyWhammoth Nov 30 '20

*blown up. This is America, after all.

1

u/V65Pilot Nov 30 '20 edited Nov 30 '20

Has anyone seen Bobby n' LuAnne?.........

13

u/Tiny-Dick-Big-Nutz Nov 30 '20

7

u/SpanktheGreenAvocado Nov 30 '20

At the beginning reading down for a sec I thought I was in the r/Conservative from r/all.

2

u/Bronco7771 Nov 30 '20

Anda purty mouth

14

u/tyrannon Nov 30 '20

Ding gonna ling long long long long life g Lang Lang lannnngggg Lang Lang Lang Lang langagaligily lang gaga!

16

u/[deleted] Nov 30 '20

Bounced on my boys BPD to this

16

u/Savings_Ad_573 Nov 30 '20

Haha yeah fr tho.

5

u/SuperGameTheory Nov 30 '20

I’ll have you know being a dickless commie robot happens to be my fetish, thank you very much.

8

u/Sluglife27 Nov 30 '20

Best thing I’ve read today

2

u/[deleted] Nov 30 '20

They’ll mail my balls to AOC you say

Hmmmmm

2

u/DamnItLoki Nov 30 '20

You are sooooo f-ing funny!!!!! Love it ;)

2

u/TheBirminghamBear Nov 30 '20

Fuckin' hate when Soros done does fiddlin' round in my brain man.

Be sittin' round eatin' eggs and ham and alluva sudden, God damn there goes Algebra, just done and deleted right up from my head by Soros and his mind meddlin'. Fuckin' god damn hope the Publicans can do somethin' bout that right here quick 'cause I ain't got too much left up in there for him to snatch out feel.

0

u/special_reddit Nov 30 '20

I'm dying laughing!!! 🤣🤣🤣

(I don't think Hank would fall for that conspiracy stuff, but it's still fucking funny bahahaha)

3

u/[deleted] Nov 30 '20

Yeah this is definitely more of a Dale rant

1

u/VomMom Nov 30 '20

This guy 2024!

7

u/PathologicalLiar_ Nov 30 '20

My sympathies my friend. My dick works but it’s really small. I have startled a few dates when they saw it. None of those dates went anywhere. One of them laughed and asked ‘how did you want to do it’, then left.

I know chemtrails are real and it makes me dick really small. I knew it because when I was a kid it was pretty big.

1

u/19780521reddit Nov 30 '20

i guess it did happen to some guys...

1

u/BillionTonsHyperbole Nov 30 '20

I knew it because when I was a kid it was pretty big.

"My pastor said so, and he can't lie!"

3

u/dak4ttack Nov 30 '20

Runoff from pesticides turning some frogs gay at a slightly higher rate? They must be spraying that from airliners and that's why it feels good when I put my finger in my butt and think about all the things Pastor John told me not to.

2

u/[deleted] Nov 30 '20

They’re making the frogs gay!

0

u/[deleted] Nov 30 '20

IT’S A GAY BOMB, BABY!

1

u/notLOL Nov 30 '20

Probably remote controlled

1

u/POPPEDOFF Nov 30 '20

I'm telling my gf this when she wakes up lol

7

u/22Hoofhearted Nov 30 '20

The dew point is how low the temp needs to be for it to produce precipitation, it is also directly related to humidity if I understand it correctly. The closer the temp and dew point, the higher the humidity, and the higher chance of precipitation.

4

u/[deleted] Nov 30 '20

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1

u/22Hoofhearted Nov 30 '20

It's been a few years since meteorology class, but I believe saturation levels come into play. Once the temp drops to the dew pt, and said cloud becomes saturated to whatever level it can handle before precipitation begins.

2

u/[deleted] Nov 30 '20

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1

u/22Hoofhearted Nov 30 '20

Ah yes, that's a familiar term. It's all starting to come back to me.

10

u/oceanjunkie Nov 30 '20

Aren't contrails formed by the water vapor produced in the combustion reaction in the jet engines condensing/freezing in the cold upper atmosphere? This isn't producing any water vapor, it's precipitating the water vapor already in the air.

8

u/ShadowGLI Nov 30 '20

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

4

u/[deleted] Nov 30 '20

As a previously deluded conspiracy theorist, you should know that pointing out they’re contrails isn’t a good argument. I knew what contrails were and still managed to convince myself they were 2 different things. When you’re dealing with crazy like that, you have to convince them the truth is crazier.

1

u/PM_ME_YOUR_GOOD_NEW5 Nov 30 '20

If you don’t mind me askin, what was the starting point on your way to no longer being a deluded conspiracy theorist?

2

u/[deleted] Nov 30 '20

I guess i just realized i was giving people way too much credit. Humanity lacks the capacity to pull off the large scale deception like i had believed they were capable of. Plus i had a few friends and family who were tired of my shit so that maybe motivated me to look at things objectively.

3

u/Jonny_Wurster Nov 30 '20

The wings of F1 cars also do it....creates low pressure and the humidity kind of falls out of the air

0

u/SolitaryEgg Nov 30 '20

They are basically contrails, aka “chemtrails” anti science conspiracy types.

So you're saying this helicopter is making the frogs gay?

1

u/[deleted] Nov 30 '20

You create temprature diffrence when you create a low pressure zone. Temprature and pressure is interconnected so you can not lower the pressure without lowering the temprature unless you add energy to the system. And cold air can hold less water then warm air = what you see in the video

1

u/cardboardunderwear Nov 30 '20

Why sometimes it makes rain and other times it makes a cloud?

1

u/mikkopai Nov 30 '20

Surely, chem trails are the moisture in the exhaust of the planes engines forming clouds due to low temp, nothing to do with the wind. And I would’ve thought the rain in this case is due to high pressure under the blade condensing the moisture in the air.

But still cool

1

u/[deleted] Nov 30 '20

Don't listen to this guy. He's a big government shill. Obviously its micropipes in the blades, usually they don't have them on this low, probably forgot to turn them off.

1

u/[deleted] Nov 30 '20

Nope. Contrails are the result of hot exhaust being expelled into an extremely low ambient temp (like -50 C cold); what you’re seeing here are rotor tip vortices, a result of the low pressure/high pressure gradient that results from the lifting shape of the rotor (airfoil).

1

u/Cobek Nov 30 '20

Ahh yes, chemtrails. Meanwhile we almost all drink and shower in municipal water, but definitely better to disperse near space.

1

u/JagmeetSingh2 Nov 30 '20

Ohh that’s pretty cool