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Awesome!

One thing that bugs me a bit about RealPlume is that exhaust animation is rather slow. IRL hypersonic flames are super fast even in slow-mo playback. So realistic effect might be achieved if flame particles are stretched and blurred (statically) a bit along the direction of motion while moving super fast (almost indistinguishable between really moving or just being randomly sprinkled over plume area each frame).

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I need to make a correction here:

Quote

An atmosphere with a lot of water moisture will cause more vapor in the exhaust plume.  This is a result of the high temperature of the exhaust vaporizing the moisture in the air, causing visible cloud-like trails.

Wrong. The exhaust plume, if a result of hydrocarbon or hydrogen combustion, already contains a lot of moisture. We see cloud-like trails when the exhaust gas cools down and the moisture condenses. If the atmosphere is very dry, then the moisture won't be able to condense because the dry air will dissolve the moisture and the trail will disappear. If the atmosphere is already humid, then the exhaust moisture will saturate the air and that is when condensation happens and we see a trail.

Attaching the picture of a plane contrail passing through a patch of drier air (I seem to recall rockets plumes doing the same but can't find pictures for now).

Brokencontrail72dpiMIMS.jpg

Wow look at this:

SDO-launch-034.jpg_(580%C3%97340)-201003

Source: https://contrailscience.com/why-do-some-planes-leave-long-trails-but-others-dont/

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Just now, MechBFP said:

I guess one thing for the devs to note is that fuels that don’t create H20 as a result of combustion therefore probably shouldn’t produce contrails regardless of ambient atmospheric moisture levels.

Yes, hydrocarbons and hydrogen, when burned with oxygen, produce water. Contrails have to do with relative humidity and adding more water to already saturated air.

Cumulous clouds are large pockets of saturated air and the flat bottom of them is a critical point along a temperature gradient. Since hot air holds more water and hot air is closer to the ground, at that point where the air gets just warm enough to not be 100% saturated, the moisture pocket becomes see through and the bottom of the cloud is formed :) And that's why cumulus clouds look like shaving cream on curvy glass table

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Oh, awesome! Stock RealPlume is good to see, and those explosions are going to be so much fun... Failure is a fundamental part of KSP and it's important that failure looks awesome too!

edit: dangit forum, double post?

Edited by RealKerbal3x
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On 2/27/2020 at 7:17 AM, ioresult said:

We see cloud-like trails when the exhaust gas cools down and the moisture condenses.

This correction is worth Private-Division's while to make in their post, before they get too much abuse.

Gliders occasionally make wingtip contrails by creating vortices with low-pressure in their centers, the expansion cooling the air just a bit, sometimes enough to let vapor condense into visible droplets.

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On 2/27/2020 at 9:17 AM, ioresult said:

I need to make a correction here:

Wrong. The exhaust plume, if a result of hydrocarbon or hydrogen combustion, already contains a lot of moisture. We see cloud-like trails when the exhaust gas cools down and the moisture condenses. If the atmosphere is very dry, then the moisture won't be able to condense because the dry air will dissolve the moisture and the trail will disappear. If the atmosphere is already humid, then the exhaust moisture will saturate the air and that is when condensation happens and we see a trail.

Attaching the picture of a plane contrail passing through a patch of drier air (I seem to recall rockets plumes doing the same but can't find pictures for now).

 

Wow look at this:

 

Source: https://contrailscience.com/why-do-some-planes-leave-long-trails-but-others-dont/

I'd be curious to know the answer. I suspect rockets have several effects distinguishing them from aircraft

1) They put out an awful lot of propellant in a short time, and probably dump out much more water per second than comparable jetliners.

2) They swiftly leave aircraft in the dust; at 1 km/s, even if you're dumping more water per second, it's spread over a longer distance.

3) At a high enough altitude, I suspect the contrails just disappear as there ceases to be enough atmosphere to meaningfully condense the water.

Edited by Starman4308
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