Re: How Rockets Differ From Jets

"tomcat" <jlavine@xxxxxxxxxxxxx> wrote:

:
:Fred J. McCall wrote:
:> :Nothing magical about a SSME. Rocketdyne makes them. They work. They
:> :produce 450,000 pounds of thrust each at sea level, 500,000 pounds of
:> :thrust each in Space.
:>
:> I don't see any spaceplanes using 11 of them flying to Venus today.
:> Perhaps you do?
:
:Such a spaceplane is getting discussed here precisely because it hasn't
:been built yet. It is the future of Space Engineering.
:
:A spaceplane with 11 SSME's would have 5.5 million pounds of thrust at
:full throttle in space. That is a lot of thrust. Combined with a very
:light dry weight it just about could work 'magic'.

<snicker>

:> :A good spaceplane would be a combination of extremely light materials,
:> :like carbon nanotube fabric, and . . . vacuum. It just might float.
:>
:> In which case it is not acting as a spaceplane and will be in pieces
:> from forces hitting it from the wrong directions.
:>
:> Engineering ain't magic, Tomcat.
:
:We are not talking about 'bailing wire and bubble gum' here.

Well, when you start looking at the magnitude of forces exerted by
Venus' atmosphere, yeah, you are.

:Both basalt fabric and nanotube fabric have enormous toughness and
:strength. Nanotube fabric -- recently developed at the University of
:Texas -- is not only 600 times stronger than steel for a given amount
:of weight, but can take many thousands of degrees of heat.

Which is still irrelevant. Strength per weight is a lousy measure of
your vehicle being 'stronger' unless you're looking at using something
close to comparable weights as you would steel.

--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
.

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