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Skylon

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3 minutes ago, StupidAndy said:

what's a crush core?

The F9 legs have internal "cores" made of aluminum honeycomb. Think a shock absorber that can only move once. On a hard landing, the crush core gets smushed-by design-thereby absorbing energy and saving more important components (like the engines). They tried using the engine as a shock absorber on a couple of the Apollo landings, turns out it was a bad idea. :wink:

A tweet from Elon said they can replace a crush core in just a couple of hours.

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Just now, CatastrophicFailure said:

The F9 legs have internal "cores" made of aluminum honeycomb. Think a shock absorber that can only move once. On a hard landing, the crush core gets smushed-by design-thereby absorbing energy and saving more important components (like the engines). They tried using the engine as a shock absorber on a couple of the Apollo landings, turns out it was a bad idea. :wink:

A tweet from Elon said they can replace a crush core in just a couple of hours.

I should read into this, don't exactly know what a shock absorber is, TO WIKIPEDIA!

oh and thanks :D

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3 minutes ago, StupidAndy said:

I should read into this, don't exactly know what a shock absorber is, TO WIKIPEDIA!

oh and thanks :D

Lol, ok technically what you're looking for on wiki is a damper, but on cars everyone calls them shock absorbers. It's a tube sliding inside another. Vaguely like this: 

 

But at the bottom of the outer tube, you have a slug of aluminum honeycomb. This part of the leg collapses on impact, absorbing it. 

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Just now, CatastrophicFailure said:

Lol, ok technically what you're looking for on wiki is a damper, but on cars everyone calls them shock absorbers. It's a tube sliding inside another. Vaguely like this: 

 

 

But at the bottom of the outer tube, you have a slug of aluminum honeycomb. This part of the leg collapses on impact, absorbing it. 

is it like those parts of a car that crumple to reduce shock? crumple zones?

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6 hours ago, CatastrophicFailure said:

So, given that the landing was hard enough to crush all 4 crush cores, that barge must have really felt it. 

The question now is, will they have to change the name? :wink:

Oooh - there are so many good ones to choose from :) Only Slightly Bent would be an obvious choice, although Screw Loose (along with a bunch of other stuff I imagine) might work or possibly So Much for Subtlety. 

Lasting Damage is probably a bit direct. :) In fact calling it that would have Very Little Gravitas Indeed. 

I'll stop now - I love Culture ship names though.

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14 minutes ago, KSK said:

Oooh - there are so many good ones to choose from :) Only Slightly Bent would be an obvious choice, although Screw Loose (along with a bunch of other stuff I imagine) might work or possibly So Much for Subtlety. 

Lasting Damage is probably a bit direct. :) In fact calling it that would have Very Little Gravitas Indeed. 

I'll stop now - I love Culture ship names though.

How about Funny, It Worked Last Time

You'll Thank Me Later (The barge) 

Size Isn't Everything

Someone Else's Problem

Fine Until You Came Along (the barge was)

Wow that wiki page is a goldmine for barge names.

 

 

Edited by Skylon
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6 hours ago, CatastrophicFailure said:

Lol, ok technically what you're looking for on wiki is a damper, but on cars everyone calls them shock absorbers. It's a tube sliding inside another. Vaguely like this: 

But at the bottom of the outer tube, you have a slug of aluminum honeycomb. This part of the leg collapses on impact, absorbing it. 

Do the legs has standard dampers too? i Thought the cylinders who lower the legs worked as shock absorbers.
 

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2 hours ago, magnemoe said:

Do the legs has standard dampers too? i Thought the cylinders who lower the legs worked as shock absorbers.
 

No, the legs lock once the pneumatics have extended them. This is because the pneumatics have only just enough pressure to extend the legs and no more (because high-pressure pneumatics are too heavy), so they don't have the force to keep them extended during touchdown.

It was failure of one of the leg-locks which caused one booster to fall over after landing. I am sure somebody will remind me which one!

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2 hours ago, softweir said:

It was failure of one of the leg-locks which caused one booster to fall over after landing. I am sure somebody will remind me which one!

I don't remember what the mission name was, but it was the first landing attempt off Vandenberg and morning mist/fog caused the locking collett to ice up

 

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2 hours ago, softweir said:

No, the legs lock once the pneumatics have extended them. This is because the pneumatics have only just enough pressure to extend the legs and no more (because high-pressure pneumatics are too heavy), so they don't have the force to keep them extended during touchdown.

It was failure of one of the leg-locks which caused one booster to fall over after landing. I am sure somebody will remind me which one!

You don't need high pressure pneumatic, or rater the landing creates the pressure,this assuming the entire down movement is pneumatic and not gravity for the last part. 

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1 hour ago, WildLynx said:

You need high pressure in pneumatic shock absorber to make it work. Or else it will collapse all the way under weight of single Lynx. Air is easily compressed...

You are correct, I was thinking hydraulic. pneumatic would not work unless high pressue, and yes using the huge cylinders for pneumatic would be way to heavy while pneumatic would work well for lowering them. 
 

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