Author Topic: The Reaction Engines Skylon/SABRE Master Thread (6)  (Read 173709 times)

Offline ChrisWilson68

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #640 on: 06/22/2017 06:45 AM »
...
Skylon requires a lot of money and good engineering.

A full reusable VTO TSTO needs several breakthroughs in physics which may (or may not) happen.
...

Wha..? I don't even know where to start. The rest of your rant makes little sense,

Not only does it make little sense, it's all been posted by the same poster and thoroughly debunked by multiple people multiple times.  But the same nonsense keeps getting posted again and again.

Offline Vultur

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #641 on: 06/22/2017 08:22 AM »
Reusable SSTO, VTVL or otherwise, doesn't require any fundamental breakthroughs. The question is economic, since you need a larger vehicle for the same payload.

At most VTVL SSTO requires a somewhat better TPS material... OTOH PICA-X may well be good enough, given the things ITS is supposed to do. Materials technology has come a long way since the Shuttle TPS was designed.

I think the reentry aspect is really the only thing that could be considered undemonstrated. The launch part would be like any conventional rocket, except for the lack of staging, which only makes things simpler; and the terminal landing profile would be like SpaceX's first stages.

The mass ratio would have to be good, but mass ratios that would be SSTO class with modern engines have been demonstrated since the early 60s (Titan II first stage for example... the mass ratio on the old Atlas was completely ridiculously low, but it was probably too flimsy for reentry...)

Offline t43562

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #642 on: 06/28/2017 07:58 AM »
Reusable SSTO, VTVL or otherwise, doesn't require any fundamental breakthroughs. The question is economic, since you need a larger vehicle for the same payload.

Then it requires some kind of breakthrough to be economic?

Offline hkultala

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #643 on: 06/28/2017 08:50 AM »

1) SX can't do 2nd stage return from orbit.  In 2011 they thought they could. Then in 2014 they said it was off the table for all F9 derived hardware. Now they are saying it may be possible after all.'

They have NEVER said they CANNOT do it. They have said THEY HAVE NO IMMEDIATE PLANS TO DO IT.

And the reason is that
1) The recovery hardware weights so much that it has huge impact on GTO payload, practically meaning it could not be used for most GTO launches.

2) Most F9 launches are to GTO launches, minority are LEO launches where the payload penalty is not bad.

3)  Developing the reusable second stage needs considerable amount of engineering work and they have other, better use for this engineering work.

4) Developing the reusable second stage costs certain amount of money, and for each (quite rarely-occuring) second stage reuse they save considerably smaller amount of money, the development cost might be too much to get profit.

Quote
This is not engineering. This is science. The truth is they don't know if it will work, or if it will ever work with Kerolox, although they seem more confident that it will work with Methalox. Probably. we will find out when FH launches (when is that now?)

No, it's mostly ECONOMICS.

Offline DM27

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #644 on: 07/03/2017 11:44 AM »
Not sure if this has been posted yet:

Mark Thomas gives a presentation on the future of Sabre and REL (June 13th)
« Last Edit: 07/03/2017 12:06 PM by DM27 »

Offline Hankelow8

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #645 on: 07/05/2017 02:12 PM »
Nothing new from the talk apart from again confirming Skylon is well and truly on the back burner, he seemed to suggest at least 10/15 years away. They are also exploring new areas of use for the heat exchanger and aim to set up a separate company to handle this development. They are also looking for further funding in the not too distant future.


At the UK Space Conference  I spoke to a Reaction Engines employee and he said the reduced size engine would run at mach 4.4/4.8, this would significantly reduce thermal stresses on the engine over a longer period of flight.
This would allow the engine to run for longer periods with the ability to have short boost periods in rocket mode if needed, looking more and more like an engine for a high-speed reconnaissance aircraft.

Offline alang

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #646 on: 07/05/2017 02:53 PM »
I wonder if the engine would be possible without helium as the heat exchanger working fluid. I know they've done some testing in the past with argon, presumably out of necessity borne of some of the engineering difficulties mentioned in the video.
I'm guessing it would be not compact enough for aerospace otherwise.
This table suggests that Helium is an excellent gaseous coolant if one can go on thermal conductivity with the only thing coming close being hydrogen, which seems impractical:

http://www.engineersedge.com/heat_transfer/thermal-conductivity-gases.htm

I wonder how much Helium they expect to lose in each flight, given its mobility, which seems likely to increase with temperature. How much of a cost penalty is that likely to be.

Offline Dao Angkan

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #647 on: 07/05/2017 10:52 PM »
I don't think it's a significant amount, unlikely to have an affect on cost.
« Last Edit: 07/05/2017 10:54 PM by Dao Angkan »

Offline oddbodd

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Offline Star One

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #650 on: 07/12/2017 07:32 AM »
More UK government funding for space, mostly to Harwell campus but also:

Quote
A further 4m is going to Wescott in Buckinghamshire where rocket motors are built and tested.

http://www.bbc.co.uk/news/science-environment-40573519

At least I assume it's a new 4m, govt funding has a habit of being announced more than once ...

Offline JCRM

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #651 on: 07/13/2017 10:16 AM »
but also:
Quote
A further 4m is going to Wescott in Buckinghamshire where rocket motors are built and tested.
At least I assume it's a new 4m, govt funding has a habit of being announced more than once ...
Old money, I think

Offline john smith 19

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #652 on: 07/15/2017 09:46 AM »
Oh, look at that, a super ceramic :-)

http://www.manchester.ac.uk/discover/news/chances-of-hypersonic-travel-heat-up-with-new-materials-discovery/
https://www.nature.com/articles/ncomms15836

I wonder what that could be useful for :-D
UHTC have been under research since the early 60's. This stuff does not look like it's been on the usual list of materials studied. What's interesting is its much higher resistance to surface layer damage by high speed air flow and its ability to survive in an oxygen atmosphere.

The other interesting thing is the use of "pack cementation" which is a relatively low tech (atmospheric pressure) way to infuse surface coatings, rather than say vapour deposition, which is usually done in very low pressures, which are a PITA to maintain.

That said this tech is still probably decades away from being incorporated in an actual vehicle and is unnecessary for the Skylon concept, given SiC reinforced glass is already available and well characterized.  :(
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Star One

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The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #653 on: 07/15/2017 10:27 AM »
Oh, look at that, a super ceramic :-)

http://www.manchester.ac.uk/discover/news/chances-of-hypersonic-travel-heat-up-with-new-materials-discovery/
https://www.nature.com/articles/ncomms15836

I wonder what that could be useful for :-D
UHTC have been under research since the early 60's. This stuff does not look like it's been on the usual list of materials studied. What's interesting is its much higher resistance to surface layer damage by high speed air flow and its ability to survive in an oxygen atmosphere.

The other interesting thing is the use of "pack cementation" which is a relatively low tech (atmospheric pressure) way to infuse surface coatings, rather than say vapour deposition, which is usually done in very low pressures, which are a PITA to maintain.

That said this tech is still probably decades away from being incorporated in an actual vehicle and is unnecessary for the Skylon concept, given SiC reinforced glass is already available and well characterized.  :(

Being as in the article it specifically stated this was designed for hypersonic aircraft I am not sure why it was posted in this thread especially when a general hypersonic thread already exists?

http://forum.nasaspaceflight.com/index.php?topic=37698.msg1381522#msg1381522
« Last Edit: 07/15/2017 11:11 AM by Star One »

Offline john smith 19

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #654 on: 07/15/2017 11:04 AM »
Nothing new from the talk apart from again confirming Skylon is well and truly on the back burner, he seemed to suggest at least 10/15 years away.
Watch it again. That's 8-10 years.
Quote
They are also exploring new areas of use for the heat exchanger and aim to set up a separate company to handle this development. They are also looking for further funding in the not too distant future.


At the UK Space Conference  I spoke to a Reaction Engines employee and he said the reduced size engine would run at mach 4.4/4.8, this would significantly reduce thermal stresses on the engine over a longer period of flight.
This would allow the engine to run for longer periods with the ability to have short boost periods in rocket mode if needed, looking more and more like an engine for a high-speed reconnaissance aircraft.
Did you ask that question or did they say it? Increasing life expectancy is unlikely to be a major issue.

A modern turbofan operating life is in the 10s of 1000s of hour range. Even the first turbojets in WWII could manage 8 hours.  A demonstration test engine (in a suitable airframe) needs to operate for about 16 mins to achieve orbit, and doing so (ideally returning to Earth within a day) would permanently   change peoples perceptions of what is, and is not possible.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Hankelow8

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #655 on: 07/15/2017 01:43 PM »
Yes, I did question him on the use of the engine for long periods within the atmosphere.
Although not referring to a high altitude aircraft using the engine, he did say running for long periods within the
atmosphere would suit a lower Mach no ie 4.5/4.8, this would reduce thermal and stress loads on the engine.

Of course, the lapcat Scimitar engine was supposed to be able to cruise at Mach 5 for long periods of flight, could well be they now feel this reduced Mach no is better suited for multiple flights without major maintenance needed, who knows!.

Offline john smith 19

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #656 on: 07/16/2017 10:48 PM »
Yes, I did question him on the use of the engine for long periods within the atmosphere.
Although not referring to a high altitude aircraft using the engine, he did say running for long periods within the
atmosphere would suit a lower Mach no ie 4.5/4.8, this would reduce thermal and stress loads on the engine.
In the context of SkylonSABRE that would be for self ferry to a launch site, although I didn't expect it to be operating at that high a speed. The key point about SABRE is it's basically a rocket engine adapted to operate, briefly, in the atmosphere to give the 3000sec+ Isp.
Quote
Of course, the lapcat Scimitar engine was supposed to be able to cruise at Mach 5 for long periods of flight, could well be they now feel this reduced Mach no is better suited for multiple flights without major maintenance needed, who knows!.
Doubtful. The Scimitar concept was specifically designed to operate solely in the atmosphere, hence no need for LO2 carriage, and no part of the cycle using LO2. LH2 makes for a large tank it's LO2 that makes for a heavy tank, and it's a weight conventional aircraft don't need to carry.

Launch is very different from cruise. Only the ongoing efforts to raise funds for SCramjets have tried to blur that line. 
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline nec207

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #657 on: 08/05/2017 01:03 AM »
Quote
There is already a discussion on Skylon (now on thread 6):
https://forum.nasaspaceflight.com/index.php?topic=40846.0

I' not talking about Skylon. I'm talking about Skylon engineering breakthroughs into engine these days allowing for space planes, rocket/plane combo and single-stage-to-orbit (SSTO)

Where in the past engine where just not powerful enough for space planes, rocket/plane combo and single-stage-to-orbit (SSTO).

This is off topic for that thread.

Offline Jim

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #658 on: 08/05/2017 01:07 AM »
Quote
There is already a discussion on Skylon (now on thread 6):
https://forum.nasaspaceflight.com/index.php?topic=40846.0

I' not talking about Skylon. I'm talking about Skylon engineering breakthroughs into engine these days allowing for space planes, rocket/plane combo and single-stage-to-orbit (SSTO)

Where in the past engine where just not powerful enough for space planes, rocket/plane combo and single-stage-to-orbit (SSTO).

This is off topic for that thread.

It has nothing to do with power.  Research on ISP.

Offline john smith 19

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Re: The Reaction Engines Skylon/SABRE Master Thread (6)
« Reply #659 on: 08/05/2017 09:18 AM »
Quote
There is already a discussion on Skylon (now on thread 6):
https://forum.nasaspaceflight.com/index.php?topic=40846.0

I' not talking about Skylon. I'm talking about Skylon engineering breakthroughs into engine these days allowing for space planes, rocket/plane combo and single-stage-to-orbit (SSTO)

Where in the past engine where just not powerful enough for space planes, rocket/plane combo and single-stage-to-orbit (SSTO).

This is off topic for that thread.
I'd guess the nearest thing to this is the general hypersonics thread.

https://forum.nasaspaceflight.com/index.php?topic=37698.0
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

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