[PSUBS-MAILIST] G.L. summary Pressure Hull

[Jon Wallace]

Advantage: ABS

I think the sentence being scrutinized may perhaps just be badly 
worded.  With the exception of some intricate mechanism that equalizes 
as part of a sequence to open the hatch as Jim suggested, I don't see a 
way to comply with the requirement without the involvement of 
electronics.  Philosophically I don't think I want to rely on an 
electromagnet or boolean logic giving me permission to exit the vessel.  
If Jim's mechanism turns out to be to complicated then Doug's concern is 
valid...remember Apollo 1.

Jon


On 12/11/2013 4:17 PM, Alan James wrote:
> Hi Doug,
> Elaborating on your idea.
> If you had digital pressure gauges you could have a system
> comparing the voltage of the two, & when they were in a
> similar range they would activate or deactivate an electromagnet
> that pulled back a latch that was impeding the movement of the hatch
> release mechanism. (car door lock mechanism) You would
> need a manual over-ride. Any electronics nerd could do this easily
> & the car lock mechanisms I've seen for round $20-
> With the over-pressure valve set at a couple of psi you know
> that on the surface the most over pressure there could be is
> what your over-pressure valve is set at. Under-pressure is
> not such an issue as you won't be able to physically open the hatch
> if the under pressure is too much, & hence you have to equalize.
> So I don't think it needs sophisticated monitoring.
> I'm not sure how much of an issue it would be if you opened your
> hatch with a couple of psi over-pressure. Would the dome fly
> open at 90 miles an hour, or would pressure be released incrementally
> as the hatch dogs unlatched before fully releasing.
> Obviously G.L. thinks this is an issue.
> Alan
>

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