It's
LOX/liquid hydrogen, but the
BE-4 will be LOX/liquid methane.
---------- Post added at 08:06 PM ---------- Previous post was at 07:33 PM ----------
It's great that they plan to provide great views for the suborbital tourists, but I thought windows on airliners were small for a few reasons (large pressure difference, reducing mass, etc.). Could those large windows withstand the vacuum of space, as well as being exposed to the atmosphere at velocities of up to Mach 3?
Maybe they can? 42.7'' (~108 cm) is 35% larger than the largest window of the ISS cupola (80 cm diameter circle)
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image source)
The load on the window depends on the pressurization level. Airliners IIRC can increase cabin altitude to 8,000 ft, which is about 11 psia. At 40,000 ft the outside pressure is something like 3 psia, so you only have an 8 or 9 psi differential, which would be ~1,400 lbs on a 747 window. It's a load, it needs to be accounted for in the design, but a proper thickness of acrylic supported appropriately is easy to fabricate.
Assuming that cabin altitude can be similarly lowered on Blue Origin, the pressure differential is 11 psi, and so the load is over 13,000 lbs. To keep the maximum stress to the same limits as the 747, the windows would need to be nearly 3 times as thick. The pressure window on the 747 is 0.35 inches (there is a secondary interior pane which is 0.22 inches thick). If deflection is an issue (and it might, due to foreshortening), you would need something about 4 times thicker to limit deflection. Aerodynamic loads would need to be examined too.
So Blue Origin windows would need to be a minimum of 1 to 1.5 inches thick, plus the additional framework to support the extra load. It's a 50-80 lb window vs. 3 lb for the 747. But note that the window is also replacing some pressure hull which has weight, so it isn't simply all additional weight.
But what a view! Meh, whatever, you can lift anything if you put a big enough rocket underneath it. I think the proper engineering solution here is MOAR BOOSTERS! :lol:
Note to self: Why do I do so much math when I am not at work? :blink: