Why aren’t airliners powered gliders?

Question

The Perlan high altitide glider project has the following stats

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This suggests that a glider / high altitude airliner could be economically viable and save a lot on fuel at 60000ft.

I realize this is not a complete picture, but it seems compelling. How to fully analyze this? Please list steps.

There have been a number of military gliders that are large https://en.m.wikipedia.org/wiki/Military_glider

Because gliders are slow, and the appeal of commercial air travel is crossing the country in 4 hours. — abelenky, Feb 04 '18 at 18:24
"crossing the country in 4 hours". Well that's not a very difficult goal to achieve for most of the world :-) We just need to slow down a bit. — mins, Feb 04 '18 at 18:48
@mins: In which case you could just take a train :-) Or a ship, if you're crossing the ocean. — jamesqf, Feb 04 '18 at 19:49
The graph says Vne at FL300 to FL400 is 200 to 250 kts while airlines easily do 500-600 kts. That does not look fast to me. — abelenky, Feb 04 '18 at 20:43
They are powered gliders. They are just much better at the "powered" part than at the "gliding" part. — Jörg W Mittag, Feb 05 '18 at 07:13

score 4 · Answer 1 · edited Feb 04 '18 at 18:11

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Why aren’t airliners gliders? Because it takes lots of power to move a hundred or so people across the country and gliders are by definition unpowered.

edited Feb 04 '18 at 18:11

Federico

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answered Feb 04 '18 at 17:28

Ralph J

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Powered gliders exist. Also with a much longer glide distance aka lower wind resistance. – Smith Feb 04 '18 at 17:35
@mins airliners have a glide ratio much lower than that defined for gliders. – Smith Feb 04 '18 at 18:03
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@JosephHobbs: Yes, as I wrote... they are optimized to lift 200 tons and fly at Mach .82. Else they are able to glide very well. – mins Feb 04 '18 at 18:07

Why aren’t airliners powered gliders?

1 Answers1