Re:New aircraft rises 'like a balloon'
by kbenson on Wednesday April 24, 2019 @11:09AM
(#19739126)
I was wondering about this too. Then again, I don't know the air density difference. 130 knots at half the density (not that I know if half density is a feasible figure) would impart something like half the force, I imagine. Then again, lower density affects the ability of craft that use density for lift to operate.
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> not that I know if half density is a feasible figure
1/15th - .08 kg/m^3 at 20km, 1.2 kg/m^3 at sea level. 20km is way the heck up there. And yes, it does make it difficult to build something buoyant enough, which is why the use case for this is something like a geostationary internet balloon rather than for transportation.
https://www.engineeringtoolbox.com/standard-atmosphere-d_604...
Re:New aircraft rises 'like a balloon'
by sandworm101 on Wednesday April 24, 2019 @05:08PM
(#19742606)
Density doesn't matter. As the density decreases the force of the wind does decrease, but the propulsive ability of propellers/wings also decreases. So the net effect is that the engines have to work equally hard.