Pistons/rings

Now, then, before we go too far off the deep end, let's recall that their own data also had flaws, as they knew nothing of the effects of scale on their measurments - Reynold's number. IIRC, it took a guy named Tony Fokker (who didn't now any better) to discover that a fat wing section actually worked in the real world (it did not in the small scale wind tunnel).

Instead of sealing each against the atmosphere, could you seal each stage against the former? I recall high pressure compressors with stepped pistons like this

|| || ---||--- | | | | ----| |---- | | | ( ) | | | ----------------

The bottom level for low pressure, middle for mid, upper for high--each step with a line and check valve into the next step. You'd have a smaller pressure differential and any O2 that did leak out of the high pressure would just get picked up again. You'd also only have the need for one crank. You could even add a fourth "scavenging" stage that's at atmospheric pressure, but O2--give it a long, vented line.

It was the wright's use of a drag vs lift balance that made up for the scale problem. Everyone else was using a spring scale.

Jim

Look into powered Stirling cycle engines. They can generate small quantities of LOX.

Mark

Peter Fairbrother wrote: nitrogen boils at about 15

Huh? How is it possible to make liquid oxygen from liquid nitrogen, then? All you have to do is let something be cooled by liquid nitrogen, expose it to the air, and liquid oxygen drips off it.

Jon

Yerrright. -196 C is lower than -182 C. It just doesn't look lower.

I'd call that a typo, but it's more like a brainfart.

Boil a mixture, and the nitrogen comes off first tho'. What I said.

Peter's assertion about the boiling points is incorrect.

From White's book:

Boiling point of Nitrogen = 77.3 K Boiling point of 0xygen = 90.2 K

That is why one can sometimes find LOx dripping off of LN2 cooled piping. Mostly just air though.

Jim