How does a G-suit protect you from negative G’s? I understand how it works for positive G’s but for negative G’s to do so would it need to strangle you, they dont cover you’re neck and if they did this could cause other problems

Rapid release of pressure causes a pressure differential that slows blood flow to the brain.

My source is I made up this hypothesis based on my knowledge of physics and inertia; if it’s correct, great. If not I get the correct answer.

The truth is likely it doesn’t cause enough of a pressure differential IRL to do what I described.

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They don’t - protection is against positive G only.

There’s a bit about the effect of negative G’s here - text search for “negative”: https://www.usni.org/magazines/proceedings/2008/september/pulling-gs-pilots-body-sets-limit

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truth with some modification.
IRL some G-suits have a bladder imbedded in the helmet/neck that helps with neggative G’s to some degree. not at all much, but still.

Got an example? 'cos cutting blood flow to the head at he neck doesn’t sound very clever, and there’s nothing you can do on the outside of a skull that will affect blood flow…

Edit: i don’t know what to search for in English to get English results but the helmet in JAS39 has something called “nackblåsa” which loosely translates to “neck-bladder”. its a g-bladder in the neck of the helmet that together with the mask at the front cooperate to combat g-forces.

i’m trying to find more info on its effects on negative G’s but so far the only source i have is my own memory so i might be misremembering. I’ll update if i find more info.

Thanks - found a few things about neck supports in general, such as

but no mention of them as -ve G alleviation - rather they are designed to give better fit and help alleviate the effects of +ve G loading of a heavy helmet on neck and shoulder muscles.