Reaction Engines SABRE engine (Skylon Spaceplane)

Thanks. RanulfC, you are correct as far as you go. However, SSTO projects used to be all the rage and they carry far more dead weight into orbit. Any kind of two-stage system is a great advance on them in the terms you describe. The original B.Ae concept when migrating HOTOL to a more realistic two-stage scenario was to use a subsonic mothership for the low-altitude, low-speed bit, where the demands on engine intake geometry vary dramatically from those at high Mach numbers. That really did relieve the Reaction Engines team of some notoriously intractable intake optimisation problems. That they now think it is worth grappling with those problems for the sake of lower orbiter mass is the bit I find interesting.

Interim HOTOL (the one using the An-225) was not Alan Bond team but BAe, after the two went their own, separate ways (REL was funded in 1989).

Of course if Interim HOTOL had actually been advanced then StratoLaunch would have had something to point at they could carry :)

Randy
 
... as rocket exhaust flares sideways far more than jet exhaust and cooked Skylon's tail section.
While it needed to be better addressed than REL did the answer was beefing up the insulation and adding a heat resistant structure. One of the reasons for having a TSTO instead of an SSTO is that you can adjust the structures of both stages to optimized levels.
Putting permanent re-usable structure in the path of a rocket exhaust has never been done before that I can recall. It is a pretty hairy environment and would need a raft of technological advances to cope with the violent thermal fluctuations, mechanical vibration and reactive chemicals. It's not tame like a re-entry plasma.

Then there are little things like the one-engine-out condition when too high up for the rudder to work.
That's a misson abort, throttle down to minimum of the working engine and heavy use of the RCS till you get low enough for the rudder to be effective and limp to the nearest airfield that can handle the vehicle. It was a risk but keep in mind the vehicle was designed to show off the engines and was a very conservative design given the parameters so it could afford some added structure and weight gain. Most other SSTO's can't.
Easy enough in air when you have a fin to apply a counter-torque. But in space, an engine failure would set the craft spinning faster and faster until the other engine was also cut. You would have to ensure automatic cutoff within a very short space of time and enough manoeuvring thruster authority to counter the maximum spin that might have been applied by then, and with enough reserve to decelerate for re-entry. I am not convinced that the added weight would remain manageable.

If the Space Shuttle can get the CG right with rear-mounted rockets, I don't see why B.Ae can't.
HOTOL had issues because it had two engine systems in a way since the intake and heat-exchanger mass was forward,
That second system forward of the CG just meant adjusting the wing position a little. HOTOL's main problem with the CG was that to keep it from moving aft, a more complicated fuel/oxidant tankage arrangement would have been needed and that would have weighed too much. Now I stop to think more about the Shuttle, it didn't have to balance when fully laden, as it took off vertically, so the fuel and oxidant could go anywhere. Of course nowadays we just ensure the control authority is there and let the silicon worry about the stability, so Skylon could end up highly unstable with an aft CG and still land safely.
 
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Of course nowadays we just ensure the control authority is there and let the silicon worry about the stability, so Skylon could end up highly unstable with an aft CG and still land safely.

Spot on, in a rather hilarious way that made me smile. We are living at a time when algorithms and "silicon" could make a brick fly. Have you see that Iron Man wannabee flying over Les Champs Elysées on July 14th ? the media was astounded, but I wasn't. There was a very similar "flying platform" 70 years ago, in the 50's, but instability killed it, the unfortunate pilot couldn't control the thing. It took 70 years but nowadays, algorithms can tame unstabilty. Also see all the drones and quadcopters: they are extremely ugly and an absolute insult to aerodynamics, yet they fly.


Vive la France, yes, but that is hardly knew - only with fast computing and algorithms to tame the unstability, really.
 
Thanks. RanulfC, you are correct as far as you go. However, SSTO projects used to be all the rage and they carry far more dead weight into orbit. Any kind of two-stage system is a great advance on them in the terms you describe. The original B.Ae concept when migrating HOTOL to a more realistic two-stage scenario was to use a subsonic mothership for the low-altitude, low-speed bit, where the demands on engine intake geometry vary dramatically from those at high Mach numbers. That really did relieve the Reaction Engines team of some notoriously intractable intake optimisation problems. That they now think it is worth grappling with those problems for the sake of lower orbiter mass is the bit I find interesting.

Interim HOTOL (the one using the An-225) was not Alan Bond team but BAe, after the two went their own, separate ways (REL was funded in 1989).

Of course if Interim HOTOL had actually been advanced then StratoLaunch would have had something to point at they could carry :)

Randy
Randy,

I hear you - I've been kvetching rather unsuccessfully about this very same fact over at https://www.secretprojects.co.uk/threads/stratolaunch.14179/...

Martin
 
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Martin: there is a whole bunch of papers from the decade of the 2000's - Sorensen / Bonometti "Crossbow", David J.Salt, DARPA / NASA "air launch grand trade studies", and M. Sarigul-Klijn that indeed show the advantages of air-launch. Cuts into the gravity losses, brings the delta-v to orbit tally from 9.2 km/s to barely 8 km/s.
If you are interested I will make a massive post on this forum.
 
If you are interested I will make a massive post on this forum.
Oh, yes! :D

Probably a different thread would be more appropriate, but please drop a note here once you have done so.
 
Heck don't start me on this. Since 2008 I have downloaded like crazy, I lost the count of all the Pdf I have (in fact I never, ever tried to count them... and I have a degree in archives, supposedly) :p
a rapid count just said me I have 6104 files, and it is a very uncomplete backup. I must have 5000 pdfs.
(I did not dare to write "a massive dump" because of possible scatologic interferences, you nver know, with foreign languages)
 
Archibald, I'm aware of a few authors you mentioned, but I'm definitely interested as well.
 
Chose promise, chose due (as we say in french) :cool:
 

Attachments

  • A.4.2.1 Launch Method Analysis (Air Launch).pdf
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  • Air Launch To Orbit - ALTO - Crossbow-concept, MSFC.pdf
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  • A.4.2.1 Launch Method Analysis (Air Launch).pdf
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  • horizontal air launch.pdf
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  • sarigul-klign2000.pdf
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  • sarigul-klijn2004.pdf
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Thank you!
If you still have a record of the source urls (being a good archivist!) you could just post those.
 
ha ha you have a point.
Unfortunately, no, I didn't kept the URLs, for many reasons, the idiot Frank Wolf (am I allowed to use the world idiot ? just asking, because Frank Wolf is an idiot, and there is no other word to call him that it is not rude) being a major one. Also not all downloadings were exactly *legal* (hrrrmmmm). Finally they come from a helluva amount of different sources.
 
ha ha you have a point.
Unfortunately, no, I didn't kept the URLs, for many reasons, the idiot Frank Wolf (am I allowed to use the world idiot ? just asking, because Frank Wolf is an idiot, and there is no other word to call him that it is not rude) being a major one. Also not all downloadings were exactly *legal* (hrrrmmmm). Finally they come from a helluva amount of different sources.

That last bit is especially true in trying to find them around the web :)

If you can even find them which is becoming harder to do as well. And even then I've noted a trend where certain links tend to overwhelm a search result as well. So thanks Archibald :)

Randy
 
m
ha ha you have a point.
Unfortunately, no, I didn't kept the URLs, for many reasons, the idiot Frank Wolf (am I allowed to use the world idiot ? just asking, because Frank Wolf is an idiot, and there is no other word to call him that it is not rude) being a major one. Also not all downloadings were exactly *legal* (hrrrmmmm). Finally they come from a helluva amount of different sources.

That last bit is especially true in trying to find them around the web :)

If you can even find them which is becoming harder to do as well. And even then I've noted a trend where certain links tend to overwhelm a search result as well. So thanks Archibald :)

Randy

maybe I could open a thread somewhere on that Forum called "Archibald treasure trove" and start posting all that stuff ?
On my HD it is grouped in broad themes (quite broad at times)
In The bar section maybe ?

To Overscan and the mods - any issues ? broadband copyright something else ?
 
Press Release:

Reaction Engines has successfully tested its innovative precooler at airflow temperature conditions representing Mach 5, or five times the speed of sound, marking a significant milestone in the development of its SABRE™ engine and paving the way for a revolution in hypersonic flight and space access.

The precooler heat exchanger is a vital component of Reaction Engines’ revolutionary SABRE air-breathing rocket engine and is an enabling technology for other precooled propulsion systems and a range of commercial applications.

This ground-based test achieved the highest temperature objective of the Company’s HTX testing programme and took place at its specially constructed unique facility at the Colorado Air and Space Port, United States.

During the latest series of tests, Reaction Engines’ unique precooler successfully quenched airflow temperatures in excess of 1,000°C (~1,800°F) in less than 1/20th of a second. The tests demonstrated the precooler’s ability to successfully cool airflow at speeds significantly in excess of the operational limit of any jet-engine powered aircraft in history. Mach 5 is more than twice as fast as the cruising speed of Concorde and over 50% faster than the SR-71 Blackbird aircraft – the world’s fastest jet-engine powered aircraft.

This most recent test builds upon the success of previous HTX hot tests undertaken in April which saw the precooler successfully operate at temperatures of 420ᵒC (~788ᵒF) – matching the thermal conditions corresponding to Mach 3.3 flight.

Commenting, Mark Thomas, Chief Executive, Reaction Engines, said:

“This is a major moment in the development of a breakthrough aerospace technology which has seen Reaction Engines’ precooler tested at Mach 5 airflow temperature conditions, smashing through previous achievements at Mach 3.3 temperatures and paving the way for hypersonic flight. In addition to its use in our SABRE class of air breathing rocket engines, there are numerous exciting commercial applications for our precooler technology, which delivers world-leading heat transfer capabilities at low weight and compact size, and we are seeing significant interest from a range of potential customers and technology partners.”

Reaction Engines’ patented precooler heat exchanger has the potential to be used in a wide range of commercial thermal management applications. These include the development of precooled systems that would significantly enhance the performance of existing jet engine technology, along with applications in automotive, aerospace, energy and industrial processes.

The major testing milestone is the culmination of 30 years of engineering innovation since Reaction Engines was founded in 1989 by three propulsion engineers from Rolls-Royce, Alan Bond, Richard Varvill and John Scott-Scott.

Richard Varvill, Reaction Engines’ co-founder and current Chief Technology Officer, said:

“This is a momentous landmark for Reaction Engines in the development of its SABRE engine, which has the potential to revolutionise both access to space and high-speed flight by powering aircraft to five times the speed of sound. The performance of our proprietary precooler technology was validated at hypersonic flight conditions and takes us closer to realising our objective of developing the first air-breathing engine capable of accelerating from zero to Mach 5.”

The HTX hot heat exchanger testing programme is a significant milestone on the roadmap to enabling transformational SABRE powered space access systems and has been keenly supported by the UK Space Agency (UKSA) and European Space Agency (ESA). In March, the two agencies reviewed and validated the preliminary design of the demonstrator engine core of SABRE, which Reaction Engines will use to undertake ground-based testing at its under-construction TF1 test facility at Westcott, Buckinghamshire, UK.

The HTX hot heat exchanger test programme was supported under a contract to the Company’s US subsidiary Reaction Engines Inc. by the Defense Advanced Research Projects Agency (DARPA). The precooler test item was designed and constructed at Reaction Engines’ headquarters in the UK, before being shipped to the Company’s Colorado site for testing.

Following this significant testing milestone, the Company will embark on achieving the next steps of the SABRE programme while also pursuing nearer-term opportunities that will benefit from the addition of the Company’s heat exchanger technology.

Over the last four years Reaction Engines has raised over £100m from public and private sources and has secured investment from BAE Systems, Rolls-Royce and Boeing HorizonX.

Commenting on this achievement, Science Minister Chris Skidmore said:

“The SABRE engine is one of the UK’s most exciting engineering projects which could change forever how we launch satellites into orbit and travel across the world. It’s fantastic to see Reaction Engines passing this significant milestone, which demonstrates how its precooler technology can deal with the extreme temperatures associated with travelling at five times the speed of sound. The government has invested £60 million in SABRE and is committed to taking a more strategic approach to space, developing our national capabilities to complement and expand on the UK’s leading role in the European Space Agency once we leave the EU.”

 
Encouraging progress. Still, all it really is is a step up from simulated Mach 3.3 to Mach 5 conditions for the precooler. A long road still ahead.
 
FighterJock,

it truly is - I still vividly remember describing the SABRE engine concept as a thermodynamicist's dream and an engineer's nightmare a long time ago in a forum far, far away. Richard Varvill, if you can read this, please know that I'm busy looking for the tastiest recipe for preparing crow that I can find... Kudos and congratulations to you and the whole Reaction Engines team for your stalwart vision, tenacity and perserverance!

Martin
 
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I still vividly remember describing the SABRE engine concept as a thermodynamicist's dream and an engineer's nightmare a long time ago in a forum far, far away. Richard Varvill, if you can read this, please know that I'm busy looking for the tastiest recipe for preparing crow that I can find... Kudos and congratulations to you and the whole Reaction Engines team for your stalwart vision, tenacity and perserverance!

ISTR the "impossibility" of the precooler was pretty much the reason Rolls-Royce ducked out at the time. It cost them a lot to buy back in when the time came.

I guess the bit I'm really waiting for is the full helium+hydrogen cycle at scale, including the heat exchangers on the preburner exhaust and H2 fuel turbopump. That precooler heat is not going to be wasted!
 
I still vividly remember describing the SABRE engine concept as a thermodynamicist's dream and an engineer's nightmare a long time ago in a forum far, far away. Richard Varvill, if you can read this, please know that I'm busy looking for the tastiest recipe for preparing crow that I can find... Kudos and congratulations to you and the whole Reaction Engines team for your stalwart vision, tenacity and perserverance!

ISTR the "impossibility" of the precooler was pretty much the reason Rolls-Royce ducked out at the time. It cost them a lot to buy back in when the time came.

I guess the bit I'm really waiting for is the full helium+hydrogen cycle at scale, including the heat exchangers on the preburner exhaust and H2 fuel turbopump. That precooler heat is not going to be wasted!

In a hypersonic aircraft for example rather than an orbital vehicle wouldn’t you want to be getting rid of all the heat you could.
 
In a hypersonic aircraft for example rather than an orbital vehicle wouldn’t you want to be getting rid of all the heat you could.

Yes, but preferably via the engine exhaust where it actually does some good. SABRE does exactly that, having first used it to drive the helium and LH2 pumps along the way. Pretty dam' neat, huh?
 
From Aviation Week:

Reaction Engines Precooler Passes Hypersonic Test

Reaction Engines’ precooler has successfully run at Mach 5 temperatures, validating for the first time the capability of the novel heat exchanger design to operate at hypersonic flight conditions for atmospheric and space access applications.

The breakthrough test is pivotal to Reaction’s goal of using the lightweight heat exchanger (HTX) to boost high-speed turbojets for supersonic and hypersonic vehicles as well as for developing the company’s Synergistic Air-Breathing Rocket Engine (Sabre), which is targeted at low-cost, repeatable access to space.

Forming the culmination of a DARPA contract awarded in 2017, the Mach 5 run took place in the second week of October at the company’s TF2 test facility at the Colorado Air and Space Port near Watkins. Established on an all-new site just 22 months ago, the high-speed test comes seven months after the heat exchanger demonstrated operation at supersonic conditions equal to Mach 3.3. Heated air for the tests is generated by a General Electric J79, which operated at military power for the supersonic runs and in maximum afterburner for the tests up to Mach 5.

“We had high confidence but, until these tests over the past six months, there was just an assumption this technology would work at these high temperatures because there was no way to test it. So, I’m very glad it came off,” says Adam Dissel, president of Reaction Engines. Although initial tests in the UK in 2012 using a Rolls-Royce Viper turbojet demonstrated the ability of the HTX to chill air from ambient to under -120C (-184F), the larger-scale evaluations in the U.S. were viewed as the true acid test. “Taking the whole device up to these high temperatures as part of an integrated system is quite a design challenge,” he adds.

Describing the test result as a “major moment in the development of a breakthrough in aerospace technology,” Reaction Engines CEO Mark Thomas says: “We are seeing significant interest from a range of potential customers and technology partners.”

The precooler is made up of 16,800 thin-walled tubes (equal to more than 27 mi. of tubing) through which helium is pumped to remove heat. In the Colorado tests, the heat is rejected into water that boils off to the atmosphere, but in a Sabre it would be cooled by a hydrogen heat exchanger. “In the Mach 5 test, the temperature was reduced from around 1,000C to roughly 100C in less than 1/20th of a second,” says Dissel.

The final amount of cooling is dependent on the temperature of the heat sink used in the test. “In the current campaign, we rejected heat to a water boiler; the test done several years back in the UK rejected heat to a liquid nitrogen boiler,” he notes. “The ultimate choice for a flight system as to what temperature you cool the air down to is an integrated trade study depending on the application. Our current thoughts are that for either Sabre or precooled jet engines, you would likely not need to cool down to cryogenic temperatures.”

For high-speed turbojet applications in the nearer term, the HTX significantly reduces compressor delivery temperature (T3). This maintains sea-level conditions in front of the compressor over a wider range of speeds, thus maximizing net thrust. For space access applications, the HTX will pass chilled air to a turbo-compressor and into a rocket thrust chamber, where it will be burned with subcooled liquid hydrogen fuel.

Following the activation of the afterburner system on the J79, the team took a build-up approach toward hitting the high Mach target. “Through early summer, we tested multiple points of the envelope, eventually running up to about Mach 4.3. We tested at various airflow rates with varying coolant rates of helium mass flow passing through the precooler,” says Dissel.

The approach yielded “a good understanding of the physics and the air-pressure drop across the matrix as it transitions across the precooler,” he adds. The results also indicate the HTX responds quickly to variable airflow conditions. “The precooler has behaved amazingly well,” Dissel says. “It adapts to changing flow nearly instantly, so that was good to see. It’s part of a function of how light it is, so the precooler is not relying on thermal inertia to survive.”

By the time tests got to Mach 4.3 levels, however, the group realized that the test infrastructure was approaching heating limits before the precooler could reach its planned test condition. “The challenge we have had on the facility side was tricking it into thinking it’s flying on a Mach 5 aircraft. To ensure we had the right condition, we took a couple of months to make some upgrades and added insulation blankets to reduce the heat transfer into the walls of the airflow ducts and plenum,” he adds.

The upgrade, which also involved increasing the mass flow of the helium cooling circuit, made sure “we were ready to go for gold on the max condition,” Dissel notes.

Reaction Engines is now conducting a detailed examination of the HTX prior to assembling updated versions more tailor-made for testing with jet engines—though this time in front of the engine rather than sitting in its exhaust. “We’d like to apply the learning from this test to see what can be done for precooled propulsion next,” says Dissel. “We are very interested in the ability to enable a fast jet engine and to be able to demonstrate that here on the ground and then transition that to flight-test opportunities. That’s the next progression, and this buys down a major risk element of the Sabre engine.”

For an initial step, Reaction is studying the relatively small GE J85. “That’s our candidate at the moment. If we can show a jet engine operating at 20-40% past its design point, that would help prove the value proposition as quickly as possible,” he adds. The current precooler is sized for airflow rates of around 30 lb./sec. making it suitable for such an engine.

In the UK, where work is underway toward testing the core of the Sabre engine in 2021, Reaction is also starting an effort to evaluate the precooler with a Eurojet EJ200 under a £10 million ($13 million) project announced in July by the Royal Air Force’s (RAF) Rapid Capability Office. The project, which also involves BAE Systems and Rolls-Royce, is intended to inform engine studies for Britain’s future combat aircraft, the Tempest.

The RAF says the effort could also lead to lower costs both in terms of purchase and maintenance, a key focus of Britain’s Future Combat Air System Technology Initiative to research and develop new technologies that can be injected into UK Eurofighter Typhoons and Lockheed Martin F-35s as well as potentially feature in a future Typhoon replacement in the 2030s.
 
Reaction Engines awarded contract by Nammo UK

Reaction Engines and Nammo UK have signed an agreement for the supply of a rocket plume heat exchanger for the UK’s new National Space Propulsion Test Facility.

Nammo UK has recently been awarded a multi-million Pound contract by the European Space Agency to construct and operate the UK National Space Propulsion Test Facility at Westcott Venture Park, Buckinghamshire, UK.

The National Space Propulsion Test Facility will provide world-leading facilities within the UK that will enable rocket engines up to 1.5kN to be tested in high-altitude vacuum conditions, cementing Westcott as the centre of excellence for space propulsion within the UK.

The Applied Technologies division of Reaction Engines, recently formed to develop and deliver commercial opportunities from the Group’s patented, revolutionary heat exchanger technologies, is leading the design and manufacture of the rocket plume heat exchanger. This is a key element of the test facility and will enable rocket exhausts to be reduced from temperatures in excess of 2,000°C to just 50°C.

Steve Gill, Chief Commercial Officer, Reaction Engines said:

“Reaction Engines is delighted to supply Nammo UK with a world-class heat exchanger that will cool extreme temperatures in a very compact envelope, and which will be one of the first large-scale commercial applications of the knowledge and technology we have developed. This project shows Reaction Engines has world leading thermal management capability. “

Dr Hamish Nichol, Engineering Lead for Reaction Engines said:

“This project will truly demonstrate our capability to design and deliver the highest performance heat exchangers imaginable. We are particularly proud that our technology will play a key role in the UK’s new National Space Propulsion Test Facility which will be constructed adjacent to Reaction Engines’ own test facility which we are constructing for our SABRE engine"

Robert Selby, General Manager, Nammo UK said:

“We are excited to announce that Reaction Engines will be supplying an innovative rocket plume heat exchanger at the National Space Propulsion Test Facility that Nammo is developing at Westcott Venture Park following its recent contract award from the European Space Agency. Reaction Engines’ technology is a key enabler in the goal to produce low cost test facilities available to companies and research institutions around the world. This synergy within the space industry is another example of the UK’s continuing effort to lead the world in space technology and capability.”[/quote]

 
Given that ESA got all huffy over UK participation in Galileo on account of the B word, will there also be implications for its funding of the Westcott site once we leave the EU?

Meanwhile, why does anybody need a rocket plume cooler? I could understand liquefying it to help maintain the near-vacuum in the test chamber, but this only takes it down to 50 deg C.
 
Meanwhile, why does anybody need a rocket plume cooler? I could understand liquefying it to help maintain the near-vacuum in the test chamber, but this only takes it down to 50 deg C.
Presumably it means that more powerful rockets can be run in atmosphere without annoying the neighbours.
 
Meanwhile, why does anybody need a rocket plume cooler? I could understand liquefying it to help maintain the near-vacuum in the test chamber, but this only takes it down to 50 deg C.
Presumably it means that more powerful rockets can be run in atmosphere without annoying the neighbours.

According to the Reaction Engines announcement, "The National Space Propulsion Test Facility will provide world-leading facilities within the UK that will enable rocket engines up to 1.5kN to be tested in high-altitude vacuum conditions."

That suggests the precooler may be destined for a vacuum chamber. Getting rid of the rocket exhaust gases to keep the overall gas pressure down is certainly going to be a problem n there.
 
Given that ESA got all huffy over UK participation in Galileo on account of the B word, will there also be implications for its funding of the Westcott site once we leave the EU?

The EU got huffy about Galileo because it's an EU project. ESA is a separate organization, and AFAIK Britain will not leave ESA.

 
Interesting announcement in that Twittering about the last funding round for the prototype SABRE.

Also a claim that a SABRE-powered launcher would have a fraction the payload cost of a SpaceX Falcon 9. Not sure if that is based on aspirational SSTO advances or grounded in today's technology, i.e. maybe 2 stages.
 
A fully reusable SABRE-powered SSTO / TSTO would certainly be cheaper than having to produce brand new Falcon 9 second stages and fairings for each / most launches. How it'll compare against Starship will be interesting however. I do also wonder whether that $11 million includes profits.
 

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