Breakthrough or just cold air?

http://www.kurzweilai.net/is-this-th...the-jet-engine

Have I not heard this all before somewhere?

Brian



--
From the Sofa of Brian Gaff Reply address is active

On 01/12/2012 21:46, Brian Gaff wrote:
http://www.kurzweilai.net/is-this-th...the-jet-engine

Have I not heard this all before somewhere?

Brian




SSTO is technically feasible right now. It will also definitely be
economically feasible in the future - due to constant improvements in
materials technology giving greater strengths at lighter weights for
lower and lower costs.
The real question about Skylon is whether they can produce a plane at
this stage and engineer it to meet their cost estimates. We shall see.

Myself I'm just hoping one of the proposed supersonic business jets
takes to the skies within the next ten years. I'll be a happy bunny
when that happens :-)

--
T

But would there not be restrictions on where you could fly with all that
pressure wave stuff breaking peoples greenhouse windows? grin.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Hg" wrote in message ...
On 01/12/2012 21:46, Brian Gaff wrote:
http://www.kurzweilai.net/is-this-th...the-jet-engine

Have I not heard this all before somewhere?

Brian




SSTO is technically feasible right now. It will also definitely be
economically feasible in the future - due to constant improvements in
materials technology giving greater strengths at lighter weights for
lower and lower costs.
The real question about Skylon is whether they can produce a plane at
this stage and engineer it to meet their cost estimates. We shall see.

Myself I'm just hoping one of the proposed supersonic business jets
takes to the skies within the next ten years. I'll be a happy bunny
when that happens :-)

--
T

In article ,
says...

http://www.kurzweilai.net/is-this-th...the-jet-engine

Have I not heard this all before somewhere?

Just as we've heard for decades that clean, cheap, fusion power is only
a few years away.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

In article om,
says...

On 12-12-01 11:46, Brian Gaff wrote:
http://www.kurzweilai.net/is-this-th...the-jet-engine


In what way does cooling incoming air to -150° change things ? Is this
about slowing air as it passes through compressors ? Or something to do
with compressors acting on air of much greater density ?

or does this have to do with requiring denser air to get the amounts of
O2 needed for full combustion ?

For the same reason an engineer would put an "intercooler" on a car with
(multiple) turbochargers.

http://en.wikipedia.org/wiki/Intercooler

Would this entail a tank of liquid nitrogen that is expanded as it
cools
the engines during takeoff/climb, or would this be more like an air
conditioner with excess heat dumped and the nitrogen/freon/whatever
re-circulated ?

I'm pretty sure on the actual "launch vehicle" they plan on using the
LH2 on board to cool the incoming air.

Once high enough, I take it that O2 would be fed from tanks to allow the
av-gas/kerosene to burn ?

Above mach 5, on board LOX tanks would feed the engines in "rocket
mode".

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

Yes, you've heard it here.

And most of us think it's a bad idea. You're taking what's arguably the
easiest and cheapest per unit mass part of the launch vehicle and grossly
complicating it.

Tanks are relatively cheap. LOX is DEFINITELY cheap.

I'm not convinced this is the way to go. That said, if I'm proven wrong,
I'll be happy (and surprised).



"Brian Gaff" wrote in message ...
http://www.kurzweilai.net/is-this-th...the-jet-engine

Have I not heard this all before somewhere?

Brian




--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

In sci.space.shuttle message , Mon, 3 Dec
2012 13:56:46, Brian Gaff posted:

But would there not be restrictions on where you could fly with all that
pressure wave stuff breaking peoples greenhouse windows? grin.

For no more than a modest fraction of the R&D cost of an SSTO, it should
be possible to develop the unbreakable greenhouse window.

--
(c) John Stockton, nr London, UK. E-mail, see Home Page. Turnpike v6.05.
Website http://www.merlyn.demon.co.uk/ - w. FAQish topics, links, acronyms
PAS EXE etc. : http://www.merlyn.demon.co.uk/programs/ - see in 00index.htm
Dates - miscdate.htm estrdate.htm js-dates.htm pas-time.htm critdate.htm etc.

"Dr J R Stockton" wrote in message
. invalid...

In sci.space.shuttle message , Mon, 3 Dec
2012 13:56:46, Brian Gaff posted:

But would there not be restrictions on where you could fly with all that
pressure wave stuff breaking peoples greenhouse windows? grin.

For no more than a modest fraction of the R&D cost of an SSTO, it should
be possible to develop the unbreakable greenhouse window.


Then you could put your strawman behind such windows.

Developing a unbreakable greenhouse window is easy. Deploying it to
existing greenhouses is where the real cost is.

That said, the answer to Brian's question is simple, fly out over the ocean.
Not too many greenhouse (with or without unbreakable windows) out there.



--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

On 05/12/2012 09:32, JF Mezei wrote:
On 12-12-03 16:17, Jeff Findley wrote:

For the same reason an engineer would put an "intercooler" on a car with
(multiple) turbochargers.

http://en.wikipedia.org/wiki/Intercooler

OK, so the goal is to increase air density to allow better combustion ?

However, if you cool already compressed air between compressor and
combustion chamber, you reduce pressure and increase air density, but
are still pushing the same quantity of O2.

Is it correct to state that they would have to cool the air prior to it
entering the compressors so that the compressors would then suck in
denser air and thus push more air through the engine ?


Above mach 5, on board LOX tanks would feed the engines in "rocket
mode".

Does rocket mode still involve the compressors of the jet engine
spinning ? (fed with O2 instead of outside air) Or does it shift
combustion to aft of last compressor stage and propulsion hapening by
pure expansion of gas without that gas spinning any turbines before
leaving engine ?


I believe the air inlets are completely closed in rocket mode.

--
T