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Djsnowboy267

How were the Apollo Spacecraft's 3 parachutes held apart?

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I've been asking myself this question for a while now. I just can't really think of how they would keep them apart. Every time I deploy my 2 chutes in KSP and watch them clip through each other, I can't help but think of this question. Anybody know?

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would expect the attachments to be spring loaded as well, and angled out from capsule rather than all pointing in the same direction. Helps with the initial direction of inflation.

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Imagine three buckets in a triangle formation, and a constant flow of water falling into each one. When they fill up, they'll start spilling water and that water will push the other buckets away. Now Imagine the buckets are parachutes and the water is air. ta daa!

It's hard to explain, but I think you'll get it. :)

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Yeah, I don't think it requires any special engineering... I get the same effect when I attach multiple simple parachutes to my model rockets. I think it's just that the angled chutes (since they have to angle automatically when bumped together...these aren't like KSP chutes that can clip together) spill air on their inner edges, and that forces the chutes apart.

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This is weird... I was sure I've posted a photo here last night.

apollo_14_splashdown.jpg

Anyway, those chutes might have been sewn like that, with asymmetrical distribution of air channel sizes so that the resultant force spreads them apart together with some air spilling. The air doesn't spill much over the edges, though. Parachutes don't work like that. They always have channels, holes to guide air. If you don't put holes, they buckle or to be more precise, they never open completely and just flap pointlessly. That does lower the final speed, though... but not enough.

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Theres plenty of air spilling over the edges. There has to be, the parachute needs to have a high pressure region under it or it doesn't work, and that means air is spilling. The holes in the top vent some air and stabilize it, but they don't vent all the air.

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I didn't say they're venting all the air. They wouldn't work if that was the case, but there has to be some asymmetry involved.

Those holes on the top are extremely important.

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Surely asymmetry wouldn't work? After all, there is no way to ensure the 'chutes don't spin on their axes, which would cause the asymmetry to work the wrong way!

Those holes at the top are important for controlling and limiting turbulence, thus ensuring the 'chutes remain stable. Side-vents are also used for large 'chutes to help maintain stability.

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Is is possible the holes in the top are simply off center?

Hats off to the seamstresses on that one reguardless.

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The parachutes have to be symmetric, as pointed out.

There are several things going on. Air spills over. There is a vortex state running around the edge. And finally, the whole thing can have a lift component. All of these are going to play a role. And that last one is probably the only way for parachutes to end up as far separated as they are in the picture. But that does require initial separation, which is most likely provided by the vortex state.

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There is a hell of a lot of air spilling out the edges... It is one reason most rounds have a vent hole at the top of the canopy. The air spilling out of the base forces the canopies apart. No special brackets or whatever is needed.

There are several types of canopy that have special cutouts to help steer them. A TU type canopy, for example, has part of the rim cut out to help steer the canopy.

Oh and the reason I know this... I used to be a skydiver.

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I think it's funny that I was playing KSP, recreating the Apollo missions and I thought this exact same thing so I searched Google for "How do the Apollo parachutes stay apart" and low and behold, this was the top search result!  Awesome!  lol  

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I may be a bit off topic but as I recall the hole in the center of a round parachute is to prevent it from oscillating, which makes the parachute spill air from alternate sides, which increases the osculation.  I believe that at least one of the early experimenters had a hair-raising ride to earth for this reason.  Also, the way KSP clips multiple chutes is just an example of how KSP is not always as realistic as we would like.

 

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On 26.8.2016 at 3:16 AM, Fat Gordy said:

I think it's funny that I was playing KSP, recreating the Apollo missions and I thought this exact same thing so I searched Google for "How do the Apollo parachutes stay apart" and low and behold, this was the top search result!  Awesome!  lol  

Oh my sweet summerchild, do not underestimate Google's knowledge about what you do online.

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22 hours ago, cubinator said:

Actual parachutes have collision meshes, unlike those in KSP.

True, most parachutist are happy that the parachute has an collision mesh against the air. 

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I tried to search but couldn't find any information.

I would actually think that they are tied together in order to keep them from going in opposition. I remember from my paraglider license looong ago (we have a parachute as a reserve just in case) that this is what multiple parachutes do cause it's the most stable state.

But that is bad cause then they expose the side to the airflow instead of the hollow bell, resulting in less projected surface and a higher sinkrate.

Maybe there's a better photo somewhere ... or a military man/woman can shed some light on this ?

 

Edit: opposition called a downplane in english. I'm not sure whether that applies only to airfoils or to round parachutes as well ...

 

Edited by Green Baron

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