Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 420005 times)

Offline fatjohn1408

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #860 on: 11/19/2015 12:40 PM »
Sorry to take this off topic. I haven't followed this thread in a while and want to get to know a bit more about the precooler. They claim that they can cool air from 1000 C to -150 C.

During the test, did they actually do this? How did they heat up the flow to 1000 C?
If they didn't do that but instead used ambient air. How cold did the air become after it left the precooler?

I would like to know because I might think of an application for just the precooler on its own. But my understanding about it is too limited so far. So any info on the precooler that exceeds the info given on the REL site would be welcome thank you.

Offline solartear

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #861 on: 11/19/2015 06:15 PM »
http://sine.ni.com/cs/app/doc/p/id/cs-16263  or the pdf itself http://sine.ni.com/cs/app/doc/p/id/cs-16263/lang/en/pdf/yes/pdf

Has a nice diagram of the setup. A slightly modified Viper jet engine sucks ambient air through the precooler. They used liquid nitrogen, which is much warmer than liquid hydrogen. The experiment accounted for this.

The problem with cooling air has never been the 1000 C down to 0 C, but the frost from going well below 0 C. The link above shows the test setup was to sustain the airflow and cooling of the air down to -143 C.

I did not find specifics of temperature achieved beyond "substantially below -100 C for more than 5 minutes" and that the test successfully proved the technology.

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #862 on: 11/20/2015 06:46 AM »
I believe this is the first time we've heard the UKSA 60m is matching funds, released when REL has their own 60m. The following prior announcements talk about the money being released in the past tense, and to encourage investment in REL. I wonder which it is.

http://www.reactionengines.co.uk/press_release/Press_Release_17July2013_SABRE.pdf
http://www.bbc.com/news/science-environment-23332592
I think so too.

If so it's an even less generous deal that it looked originally.   :(

I imagine a subscale demonstrator would be attractive in publicising the technology beyond its use in Skylon. Other interested parties such as the AFRL would be no doubt invited to view it.
A full size, but not full thrust engine gives you all the drag of a full size engine without all the thrust to overcome it.

This (from REL's PoV) then drags you into a detailed design exercise to fund and build a flight vehicle that's either a scaled Skylon (to preserve the aerodynamics) or a completely 1 off test vehicle.

REL don't like scale models because they have scale effects which have to be compensated for and may not be fully understood, increasing the design risk scaling up.

Likewise the one off test vehicle brings all the problems of designing a flight vehicle without the benefits of transferring the solutions of those problems to Skylon. You'd want to mfg it in as conventional a way as possible to avoid the technical risks of the Titanium framework, ceramic body shell for example.

REL's original concept was for 2 test Skylons, similar in appearance but with evolving capabilities. They did not expect the 1st Skylon to be orbital capable but to give them experience and to discover where they had been conservative on margins (or where they had not been, given one of those "unknown unknowns" that come up in aeronautical testing) for the final orbit capable version.

I'm guessing the did a fair bit of cost modelling on this and this was the plan that had the lowest overall cost to implement.

What is not known outside REL is how all the testing and research has refined their confidence in their models, or equally, if it's shown areas that are not adequately modeled and will need a full scale test vehicle.

REL have made progress, and attracted good staff, by focusing on their goal and not getting side tracked. They may not have moved fast, but they have always moved in the same direction.

I doubt many people in REL have any interest in building a prototype military anything, or the appetite for the endless procurement paperwork that defense contractors seem to love.  :(
« Last Edit: 11/20/2015 06:47 AM by john smith 19 »
"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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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #863 on: 11/20/2015 01:03 PM »

I believe this is the first time we've heard the UKSA 60m is matching funds, released when REL has their own 60m. The following prior announcements talk about the money being released in the past tense, and to encourage investment in REL. I wonder which it is.

http://www.reactionengines.co.uk/press_release/Press_Release_17July2013_SABRE.pdf
http://www.bbc.com/news/science-environment-23332592
I think so too.

If so it's an even less generous deal that it looked originally.   :(

I imagine a subscale demonstrator would be attractive in publicising the technology beyond its use in Skylon. Other interested parties such as the AFRL would be no doubt invited to view it.
A full size, but not full thrust engine gives you all the drag of a full size engine without all the thrust to overcome it.

This (from REL's PoV) then drags you into a detailed design exercise to fund and build a flight vehicle that's either a scaled Skylon (to preserve the aerodynamics) or a completely 1 off test vehicle.

REL don't like scale models because they have scale effects which have to be compensated for and may not be fully understood, increasing the design risk scaling up.

Likewise the one off test vehicle brings all the problems of designing a flight vehicle without the benefits of transferring the solutions of those problems to Skylon. You'd want to mfg it in as conventional a way as possible to avoid the technical risks of the Titanium framework, ceramic body shell for example.

REL's original concept was for 2 test Skylons, similar in appearance but with evolving capabilities. They did not expect the 1st Skylon to be orbital capable but to give them experience and to discover where they had been conservative on margins (or where they had not been, given one of those "unknown unknowns" that come up in aeronautical testing) for the final orbit capable version.

I'm guessing the did a fair bit of cost modelling on this and this was the plan that had the lowest overall cost to implement.

What is not known outside REL is how all the testing and research has refined their confidence in their models, or equally, if it's shown areas that are not adequately modeled and will need a full scale test vehicle.

REL have made progress, and attracted good staff, by focusing on their goal and not getting side tracked. They may not have moved fast, but they have always moved in the same direction.

I doubt many people in REL have any interest in building a prototype military anything, or the appetite for the endless procurement paperwork that defense contractors seem to love.  :(

If the military are going to give you development money for what is after all an untried technology in actual usage then you would be foolish in the extreme to turn your nose at it, if it helps reach your goals. Anyway now that BAE have a seat at the table I suspect your belief in what REL will or will not do may be misplaced.

Offline Ravenger

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #864 on: 11/20/2015 02:09 PM »
If the military are going to give you development money for what is after all an untried technology in actual usage then you would be foolish in the extreme to turn your nose at it, if it helps reach your goals. Anyway now that BAE have a seat at the table I suspect your belief in what REL will or will not do may be misplaced.

Remember that Alan Bond had a terrible experiences with the government cancelling cancelling HOTOL, then slapping an official secrets order on the patents for the RB545 HOTOL engine which he had designed. He spent decades working around his own patents to produce SABRE.

There's also the ITAR issue, where too heavy involvement in the USA could could prevent REL from exporting their technology, though they have been working with the US military to confirm the engine's feasibility.

REL have had bad dealings with government departments before, and so may be very careful before they sign any deals that could relinquish any control over the SABRE project. How that squares with BAE buying a stake in REL remains to be seen.

Offline simonbp

Re: The Reaction Engines Skylon Master Thread (5)
« Reply #865 on: 11/20/2015 02:24 PM »
There's also the ITAR issue, where too heavy involvement in the USA could could prevent REL from exporting their technology, though they have been working with the US military to confirm the engine's feasibility.

ITAR has recently (a few months ago) become significantly less restrictive about space hardware. That may in fact have allowed the BAE deal to happen (speculation).

Offline Star One

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #866 on: 11/20/2015 03:34 PM »

If the military are going to give you development money for what is after all an untried technology in actual usage then you would be foolish in the extreme to turn your nose at it, if it helps reach your goals. Anyway now that BAE have a seat at the table I suspect your belief in what REL will or will not do may be misplaced.

Remember that Alan Bond had a terrible experiences with the government cancelling cancelling HOTOL, then slapping an official secrets order on the patents for the RB545 HOTOL engine which he had designed. He spent decades working around his own patents to produce SABRE.

There's also the ITAR issue, where too heavy involvement in the USA could could prevent REL from exporting their technology, though they have been working with the US military to confirm the engine's feasibility.

REL have had bad dealings with government departments before, and so may be very careful before they sign any deals that could relinquish any control over the SABRE project. How that squares with BAE buying a stake in REL remains to be seen.

I imagine it was less restrictive ITAR environment that partly interested BAE in the first place, plus they have plenty of experience with dealing with military bureaucracy.

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #867 on: 11/20/2015 08:35 PM »
If the military are going to give you development money for what is after all an untried technology in actual usage then you would be foolish in the extreme to turn your nose at it,
There is no indication that has happened.
Quote
if it helps reach your goals. Anyway now that BAE have a seat at the table I suspect your belief in what REL will or will not do may be misplaced.
Well there's what they will do and there's what they would like to do if they did not have other constraints.

It's not about funding. It's about control.

Remember that Alan Bond had a terrible experiences with the government cancelling cancelling HOTOL, then slapping an official secrets order on the patents for the RB545 HOTOL engine which he had designed. He spent decades working around his own patents to produce SABRE.

There's also the ITAR issue, where too heavy involvement in the USA could could prevent REL from exporting their technology, though they have been working with the US military to confirm the engine's feasibility.

REL have had bad dealings with government departments before, and so may be very careful before they sign any deals that could relinquish any control over the SABRE project. How that squares with BAE buying a stake in REL remains to be seen.
Various staff at REL also dealt with Concorde, where repeated government interference delayed the programme and wasted a lot of funds, basically becuse the French thought you could build an SST with 70 seats.

There's also the ITAR issue, where too heavy involvement in the USA could could prevent REL from exporting their technology, though they have been working with the US military to confirm the engine's feasibility.

ITAR has recently (a few months ago) become significantly less restrictive about space hardware. That may in fact have allowed the BAE deal to happen (speculation).
AFAIK this solely applies to communications satellites and parts. Launch vehicles remain dual use with all the problems that implies.

http://bizwest.com/relaxed-munitions-rules-pave-way-for-aerospace-exports/

Gives a background on the changes.

I imagine it was less restrictive ITAR environment that partly interested BAE in the first place, plus they have plenty of experience with dealing with military bureaucracy.
http://bizwest.com/relaxed-munitions-rules-pave-way-for-aerospace-exports/

Suggests your imagination is wrong.
"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 lkm

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #868 on: 11/20/2015 09:23 PM »
Just a thought on squaring the full scale test rig with the demonstration engine not big enough to power Skylon.
SABRE 3 was always two engines with a single precooler and compressor, four combustion chambers and nozzles and two of everything else, I'm not sure whether SABRE 4 is similarly designed on the airbreathing side but if it is you could imagine a demonstration engine with full scale parts but built with only one of everything so it is effectively half thrust. That way you can test pretty much everything but with a smaller engine.

I think the really pessimistic view on the BAE stake purchase is that there is no plan behind it at all, only that REL were failing to raise sufficient financing to keep everything going and the Government, having put substantial backing behind it both financial and reputationally, asked BAE to step in. 20m is really not that large compared to the size of BAE's UK government business and it's not that hard to see it as a small favour to keep a customer happy. If that's the case then BAE may have little to no thoughts on Skylon, SABRE or REL at all.

Offline Star One

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The Reaction Engines Skylon Master Thread (5)
« Reply #869 on: 11/20/2015 09:55 PM »
If the military are going to give you development money for what is after all an untried technology in actual usage then you would be foolish in the extreme to turn your nose at it,
There is no indication that has happened.
Quote
if it helps reach your goals. Anyway now that BAE have a seat at the table I suspect your belief in what REL will or will not do may be misplaced.
Well there's what they will do and there's what they would like to do if they did not have other constraints.

It's not about funding. It's about control.

Remember that Alan Bond had a terrible experiences with the government cancelling cancelling HOTOL, then slapping an official secrets order on the patents for the RB545 HOTOL engine which he had designed. He spent decades working around his own patents to produce SABRE.

There's also the ITAR issue, where too heavy involvement in the USA could could prevent REL from exporting their technology, though they have been working with the US military to confirm the engine's feasibility.

REL have had bad dealings with government departments before, and so may be very careful before they sign any deals that could relinquish any control over the SABRE project. How that squares with BAE buying a stake in REL remains to be seen.
Various staff at REL also dealt with Concorde, where repeated government interference delayed the programme and wasted a lot of funds, basically becuse the French thought you could build an SST with 70 seats.

There's also the ITAR issue, where too heavy involvement in the USA could could prevent REL from exporting their technology, though they have been working with the US military to confirm the engine's feasibility.

ITAR has recently (a few months ago) become significantly less restrictive about space hardware. That may in fact have allowed the BAE deal to happen (speculation).
AFAIK this solely applies to communications satellites and parts. Launch vehicles remain dual use with all the problems that implies.

http://bizwest.com/relaxed-munitions-rules-pave-way-for-aerospace-exports/

Gives a background on the changes.

I imagine it was less restrictive ITAR environment that partly interested BAE in the first place, plus they have plenty of experience with dealing with military bureaucracy.
http://bizwest.com/relaxed-munitions-rules-pave-way-for-aerospace-exports/

Suggests your imagination is wrong.

I didn't actually say military funding has happened. Rather I was implying that a subscale demonstrator would increase the likelihood of such funding.
« Last Edit: 11/21/2015 10:19 AM by Star One »

Offline lkm

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #870 on: 11/22/2015 10:29 PM »
Regarding ITAR. I was wondering, a while back there was a lecture where, I think, Bond was saying that there may end up being two Skylon models, an American one and a European one because of the whole ITAR problem.

Previously when thinking about possible potential Skylon consortiums it had seemed likely to be Airbus based (assuming it ever happens) and unlikely to contain any American players but that would put all the risk of failure on Airbus and leave the Americans out in the cold should the project succeed.
So I was wondering whether a consortium involving both Boeing and Airbus was possible where there is two production lines and ITAR sensitive components are duel developed and sourced resulting in distinct  American and EU models but where the costs and risks of Skylon development, as well as the potential profits are spread across the entire industry.

Is that setup at all possible under the ITAR rules?

Offline Khadgars

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #871 on: 11/22/2015 10:50 PM »
I'll admit I haven't gone through the 5 threads on this subject, and though I wish my brothers across the pond the best I don't see how this architecture pans out successfully.

It feels like the shuttle, which flew but didn't fly 52 times per year or reduce cost.

Offline Star One

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #872 on: 11/23/2015 06:33 AM »

I'll admit I haven't gone through the 5 threads on this subject, and though I wish my brothers across the pond the best I don't see how this architecture pans out successfully.

It feels like the shuttle, which flew but didn't fly 52 times per year or reduce cost.

It's not like the Shuttle much at all, other than they both have wings. Really it's closer to aviation than any winged space vehicle so far to have flown.

Offline Hanelyp

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #873 on: 11/23/2015 01:22 PM »
It's not like the Shuttle much at all, other than they both have wings. Really it's closer to aviation than any winged space vehicle so far to have flown.
That's certainly the objective.  That's also a lot closer to what was promised for the shuttle than what was delivered.  Hopefully they can get a vehicle not crippled by overwhelming maintenance demands.

Offline knowles2

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #874 on: 11/23/2015 02:14 PM »
It's not like the Shuttle much at all, other than they both have wings. Really it's closer to aviation than any winged space vehicle so far to have flown.
That's certainly the objective.  That's also a lot closer to what was promised for the shuttle than what was delivered.  Hopefully they can get a vehicle not crippled by overwhelming maintenance demands.

Even if it is, the more important thing is that they focus on eleminating those maintenance demands through upgrades and redesigns.

One of the biggest issue with the shuttle was that very little attempt was made to decrease the amount of maintenance needed after each flight and that was down to the lack of money available to Nasa.

Offline 93143

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #875 on: 11/23/2015 10:29 PM »
REL are aware of what happened with STS and appear to be attempting to minimize maintenance requirements.  Plus there's no indication of an arbitrary cost cap like the one that forced STS into the form we know.

- the TPS is much more friendly, consisting of large flexible panels, and manual inspection and maintenance is projected to take two days, though automation may be able to improve on that.

- the SABRE is lower pressure than the SSME, and by its unusual layout eliminates a number of corrosion and seals issues associated with the latter.  The mass penalty for this is largely absorbed by the requirements of the airbreathing cycle, since it needs a helium loop anyway.

- the number of fluids on board seems to be fairly well limited, with LH2, LOX, helium, water, nitrogen for the payload bay and tires, possibly a coolant for the payload bay door radiators, and...  maybe hydraulic fluid, if they don't go electromechanical?  (You can indeed do EM brakes, but honestly brake fluid is probably a fairly solid bet.)  There are certainly no toxic consumables; the OMS actually uses the same engines as the upper stage, and power is provided by hydrogen fuel cells and/or hydrolox APUs.

(Shuttle apparently employed 52 unique fluids (not 54; missile-grade air and nitric oxide are listed as "deleted"), and had 102 fluid subsystems involving 25 unique fluids that had to be serviced every flight, and in a number of cases systems using a particular fluid did not share storage and umbilicals, the standout examples being helium with 17 separate fluid subsystems and gaseous nitrogen with 20 separate service interfaces.  There were three moderately and three severely toxic fluids involved.)

- the vehicle is a single piece, fully reusable.  No dropping pieces that have to be retrieved or remanufactured and reintegrated for flight.  The only thing it drops en route to orbit is the brake coolant water.  It is also ground maneuverable and can self-ferry, which greatly eases logistics - no barges or crawlers or giant cranes.  The payload interface is standardized, as shown in the User's Manual available on REL's website, in contrast to STS which required the interfaces to be designed for each payload.

...

It seems to me that even if the initial version shows unacceptable maintenance properties, it has much more potential for low overhead than STS did.  And since the initial testing and certification involves about three times the number of flights made during the entire STS program, this sort of thing should show up early and could be largely solved before the vehicle even enters service.

A large part of why STS was so maintenance intensive is the fact that subsystems were designed and optimized independently with little thought given to maintainability.  It isn't inherent to the spaceplane concept.

One of the biggest issue with the shuttle was that very little attempt was made to decrease the amount of maintenance needed after each flight and that was down to the lack of money available to Nasa.

That's not strictly true.  For instance, SSME maintenance was reduced by 57% over the life of the program, and Block III would have dropped it further.  But yeah, major changes would have required a massive design overhaul - basically Shuttle II, which there was no money for.
« Last Edit: 11/23/2015 10:39 PM by 93143 »

Online Robotbeat

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #876 on: 11/23/2015 11:48 PM »
When, if ever, will Skylon fly? Anyone want to put down a prediction?
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Offline francesco nicoli

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #877 on: 11/24/2015 06:55 AM »
NET 2028?

(2019 full size ground engine. 2020-21 funding iatus. 2022 consortium created. 2023 subscale demonstrato 2025 beginning construction of full scale models. 2027 they are ready to fly, 2028 beginning of orbital testing)

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #878 on: 11/24/2015 01:38 PM »
When, if ever, will Skylon fly? Anyone want to put down a prediction?
1st flight.

8 years after full funding starts with the current plan.

5 years if they can manage to launch a zero payload demonstrator that flies the whole mission with their existing funding and the rest of the world "discovers" that it works as described.
"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 adrianwyard

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #879 on: 11/24/2015 10:55 PM »
A quick tangent on military applications for REL/Skylon. One capability that could command a fat check from deep defense coffers is anywhere/anytime rapid reconnaissance. I was thinking that Skylon could be good for this, but I've just read that the Falcon F9R-FT first stage is supposedly capable of SSTO, i.e. when carrying no second stage or payload+fairing. If it could manage to heft cameras etc., then that could give you overflight imagery of anywhere in less than ~30 minutes. Skylon would have one advantage over the Falcon, however: it wouldn't look exactly like a pre-emptive ICBM launch.  :o

Disclaimer: I've no idea if the SSTO claims for F9 S1 are true, or if it's capable of doing a once-around, or re-entering from orbital speed. The point is simply that while a Skylon could be useful for reconnaissance, there could be other, cheaper options available to military planners.

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