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I've been looking at some references of rockets taking off. I came across the Apollo 14 Saturn V launch and noticed that when the rocket was taking off the smoke coming from around the rocket and from underneath twisted around the rocket. I find this very peculiar. Why does this happen?

The effect is very prominent at around 42:10.

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    $\begingroup$ In my opinion, there is no twist. The smoke and the ice particles are just moved by the wind at the launch pad. If the wind is flowing by the cylindric rocket, it follows the surface partially. The movement by the wind and of the rocket looks like a twist. But I think there is no full twist of 360 degrees. We only see one side of the rocket, but we don't see what is happening behind the rocket. $\endgroup$ – Uwe Apr 21 '17 at 20:04
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    $\begingroup$ Vector sum of upward motion + horizontal wind. $\endgroup$ – Organic Marble Apr 21 '17 at 20:57
  • $\begingroup$ Bad UV mapping. $\endgroup$ – Erik Apr 22 '17 at 17:37
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The effect you are seeing is simply wind, not a twist.

twist vs wind

The reason for the diagonal direction is that the smoke is moving horizontally while the rocket is moving upwards, like this:

enter image description here

How can I be so sure about this? Well, viewing the other side of the rocket is not necessary: If the smoke was indeed ejected sideways, it would continue in the same direction because of inertia, away from the rocket as it curves away. But in the video the smoke follows the curvature of the cylinder, and that can only be explained by the wind causing a lower pressure on the leeward side of the rocket:

wind low pressure

We can also confirm this by watching a Saturn launch were the wind speeds were very low, like on the Apollo 8 mission:

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