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In lugnet.space, Jesse Alan Long writes:
> The first problem I have, Jason, is that I am not sure that everyone else is
> right, either on these bulletin boards and I know for a fact that I am not
> probably right in my ways of thought in my life. Would an overheated engine
> become a problem in outer space because if it does become a problem in outer
> space, you could always use some Castrol (variant GTX) and some Gumout Warp
> Coil Cleaner (I saw that last product in an advertisement) on your
> engine(s). I believe that poor communication leads to miscommunication
> between people and this was certainly an example of this problem, Jason.
And I thought I'd drifted off the subject... :-)
I don't know of any form of reciprocating or rotating engine that could
propel you through space, so engine oil seems a bit pointless. As for
overheating, the only way to disperse heat in space is by radiating it -
there's nothing to conduct it away, and I don't know enough to say how you'd
improve a radiating heat exchanger. I can suggest that you would design
your engine to transfer as much heat as possible into your propellant.
> We have established that there is LESS friction and gravity in outer space
No. There is negligible friction, but there is plenty of gravity - at least
within the solar system. The only reason things stay up in space is because
they're orbiting at extremely high speeds. They're constantly pulled
towards the various bodies (sun, planets, moon), but they just keep going
round and round. To travel between bodies you have to carefully calculate
trajectories to take you on paths around them, not straight towards them.
Astronauts experience 'weightlessness' or 'microgravity' because they're
falling and moving at the same speed as their capsule, not because there's
no gravity acting on them. They're actually in 'free-fall'. If their craft
came to a dead stop, it would fall to Earth. As would the moon, if it came
to a halt in its orbit.
> but now a new question occurs to my mind. You say that gas provides the
> least friction and gravity,
I said nothing of the sort.
> solids provide more gravity and friction, but
> that liquids provide the most gravity and friction. (The increase of
> gravity and friction therefore, at least to my mind, must also increase the
> amount of drag that an object uses in that type of armosphere.)
Nor that. On what do you base these statements? Gravity depends on the
mass of an object. The more massive, the more gravity. As for friction, I
made no such comparitive statements. Friction depends on the properties of
both surfaces in contact. Some liquids are very viscous and some solids are
very hard and smooth.
> What
> comprises of the most molecules in outer space and if outer space includes
> particles from all three types of matter (five in you include gels and
> plasmatic materials but they are more of a transitionatory element than an
> actual object), then how would the mixed particles react to an object that
> is moving through that domain of existence, that is how would a space craft
> be affected in terms of drag in space if all three types of objects exist in
> outer space?
This is ridiculous. You're clearly aware of advanced states of matter such
as plasma, but write in a way that shows such a fundamental lack of
understanding of simple concepts such as friction and gravity. To answer
the point, liquids do not exist in space - with no pressure around them,
they boil instantly into gas. So, you either encounter gas molecules or
solid lumps - from specks of dust to asteroids and planets. Both are so
dispersed as to act like individual particles, impacting your vehicle one at
a time.
The heat of stars, or the compression around black holes can generate
plasma, but both of these areas are bad news for your spaceship.
> I believe that the pilots of those old airplanes simply wanted to have fun
> so they flew upside down in order to appear as though they were really some
> big hot shot, that and bacck in those days, there were not that many ways to
> impress women so these pilots flew upside down to get dates with women. I
> am not sure that all of my information is correct on this subject but due to
> those first pilots, stunt flying is a fairly large business today. The Blue
> Angels (not to be confused with a Wing Commander squadron of the same name)
> and the Thunderbirds are the most modern example of this type of flying with
> aircraft.
The point was physically how the wing continues to fly inverted, given the
schoolboy model of airflow over a wing. You seems to have missed this
entirely, and I suspect deliberately.
> I have three last questions to tell you, Jason.
That's 'ask you', not 'tell you'.
> The first question is with
> air pressure on space craft. Am I right by saying that the air spilts to go
> under and over the wing but ends up meeting at the back of the wing or is it
> more complicated than that conclusion to the information, Jason?
If it's in an atmosphere, and if it's got wings, then yes. But, obviously
the air has to go over and under the wing - it's not going to pass right
through it. The point is the way the pressure is distributed, and how the
ideal balanced flow is altered by the air's viscous behaviour.
Fundamentally though, there's no force that links a point in the air above
the wing with one underneath it, so there's no reason why the air above
should keep pace with the air below - which is what the 'it has further to
go around the curve' explanation relies on.
> The second
> question is what happens as a result of the more sharpened trailing edge
> creating a wake from the wing?
You get a wake - downwash and turbulence behind an aircraft, which makes
flying another one behind it much harder. In Newtonian mechanics, you force
air downward and so get lift upward. It doesn't work out exactly, but it's
close. So, a Harrier jump-jet creates roughly as much downdraft from its
engines when hovering as you get from its wings when its flying forward. An
aircraft flying behind, in the downdraft, must generate even more lift to
stay up because the air it is flying through is moving downward.
Helicopters have a hell of a time staying up, because each rotor blade is
passing through the downwash of the one in front.
> The final question is are toroids those
> white trails that we see in the sky when jet craft are in the sky that are
> made of this steam and are also composed of those rear circulations behind
> these aircraft? I thank you for answering my letter, Jason.
> Jesse Long
Not exactly. A toroid is just a donut shape. A smoke ring is a toroid.
It's just a cylinder bent around so that the ends meet up and enclose a
space, shaped like a donut. The air flows around the front edge of a wing,
leaves two swirls in a long trail behind the aircraft, and a swirl on the
ground where it took off. If you think of these swirls as tubes of rotating
air, and join them up, you get a huge stretched out smoke ring or donut.
More like a rubber ring stretch out to several miles long, but still a loop.
You never really see a complete loop like this, as the swirling air
disperses after the plane has gone by. You only get it if you take a
snapshot of each bit of air as the aircraft passes through it. But, the
trails behind an aircraft are part of this phenomenon. Trails from the
wingtips are caused by water condensing in the middle of these swirls
('vortices' - plural of 'vortex', like a whirlpool), and the long trails you
see in the sky are water vapour from the engine exhaust condensing in the
wake of the aircraft.
Jason J Railton
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Message has 2 Replies:
 | | Re: Couldn't resist
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| (...) I was only having some fun with the oil part of the letter, I knew that you probably did not use oil in outer space, I mean, after all, the general consensus in outer space would reflect that you would use environmentally friendly materials (...) (23 years ago, 28-Jun-01, to lugnet.space, lugnet.off-topic.geek)
| | | Re: Couldn't resist
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| (...) I guess it would be based on the surface material properties. Different materials have different thermal emissivities, so picking one with a high value would be better for cooling directly to space. Of course these materials may be impossible (...) (23 years ago, 28-Jun-01, to lugnet.space, lugnet.off-topic.geek)
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Message is in Reply To:
| | Re: Couldn't resist
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| (...) The first problem I have, Jason, is that I am not sure that everyone else is right, either on these bulletin boards and I know for a fact that I am not probably right in my ways of thought in my life. Would an overheated engine become a (...) (23 years ago, 26-Jun-01, to lugnet.space, lugnet.off-topic.geek)
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