The Reaction Engines Skylon/SABRE Master Thread (7)

[Chris Bergin]

Seventh thread for Reaction Engines/Skylon.

Previous: The Reaction Engines Skylon Master Thread (6)
https://forum.nasaspaceflight.com/index.php?topic=40846.0

This has to be on topic and civil. This is for sensible debate and updates. Anything trivial or stupid will be deleted without notice.

And I mean it. Anyone trolling will get their posts removed. Anyone repeat trolling will be banned. Quote people accurately (as in the way the forum intended).

Any nonsense like we had at the end of the previous thread, and you will be banned. You have been warned:
https://forum.nasaspaceflight.com/index.php?topic=40846.msg1833819#msg1833819

[edzieba]

My original post was eaten by the last thread being locked, but JCRAM's picture of the HEX tubes brings up an important point of REL's approach: every component of Skylon (and SABRE) they can sell as a standalone commercial product is a component which does not contribute to the cost that needs to be amortised across Skylon vehicles manufactured (regardless of who operates them, they meed to be built in the first place. No bucks, no Buck Rogers). The heat exchanger, the ultralightweight landing gear, the Helium turbomachinery, the E/D nozzles, the heatsink skin, the fuselage construction method, all-up SABRE engines etc, all have applications outside of Skylon itself. Every part that is independently viable is a part that can be produced 'at cost' for Skylon, and which takes a big chunk out of Skylon's amortised development cost. It is possible I am simply miseading it, but the S-ELSE study only appears to consider SABRE and other technology spinout & sale as indirect benefits of the program, rather than as sources of direct income (or as any sort of offset against the estimated €5.3bn SABRE development cost).
With Lockheed announcing the SR-72 and Boeing announcing a hypersonic craft - and assuming either actually amount to anything - either a third party has under complete secrecy developed an air-breathing multi-cycle engine, or there is sufficient industry confidence in the eventual production of SABRE to design vehicles incorporating it, and therefore a market for it beyond just Skylon.

[john smith 19]

It is possible I am simply miseading it, but the S-ELSE study only appears to consider SABRE and other technology spinout & sale as indirect benefits of the program, rather than as sources of direct income (or as any sort of offset against the estimated €5.3bn SABRE development cost).

No, the study was quite narrowly focused. Looking at other revenue sources that could help fund the Skylon (or SABRE) manufacturer would not have been in scope. IRL REL are thinking about exactly that.

With Lockheed announcing the SR-72 and Boeing announcing a hypersonic craft - and assuming either actually amount to anything - either a third party has under complete secrecy developed an air-breathing multi-cycle engine, or there is sufficient industry confidence in the eventual production of SABRE to design vehicles incorporating it, and therefore a market for it beyond just Skylon.

The stated goal of the ground test engine (in the EU decision to allow the UK govt to invest £60m as it was not "state aid") is to advance the SABRE technology to TRL 6.

Which I read as a company understanding its technology sufficiently to design something to meet stated specifications for a machine with a high probability of success.

Which is AIUI the point at which a customer (in REL's case an airframe mfg) could come along and say
"We need an engine with this thrust fitting in an envelope no bigger than X x Y x Z and weighing no more than W  burning fuel F"
and REL saying either
"Yes we can do this"
or
"We'd have trouble meeting that parameter for that combination of thrust, weight and fuel.
We could do <other list of parameters> if you have no flexibility on this parameter, but if you could change it to <revised value> we can meet the rest of the spec."


It's that "deep knowledge" that the test engine should give REL.

Of course it also depends if the potential customer is actually serious about using REL, or if the spec is deliberately impossible so they go to their backers and "prove" they need the company they wanted to use all along.   

[t43562]

Which is AIUI the point at which a customer (in REL's case an airframe mfg) could come along and say
"We need an engine with this thrust fitting in an envelope no bigger than X x Y x Z and weighing no more than W  burning fuel F"
and REL saying either
"Yes we can do this"
or
"We'd have trouble meeting that parameter for that combination of thrust, weight and fuel.
We could do <other list of parameters> if you have no flexibility on this parameter, but if you could change it to <revised value> we can meet the rest of the spec."

At the Westcott rocket propulsion conference Alan Bond was in the audience and he emphasised that SABRE4 was a family of engines so I presume they want to have a sort of made-to-measure situation.  I am not 100% sure but it seemed to me as if they wanted at least some of the components to be the same at for each member of the family but to merely use "more" for a larger engine.  I think my understanding is crude at best though.  I imagine that the proper sizing of everything to produce a useful range of "steps" in the scale would be critical and you'd want lots of data before you set things in stone.

[t43562]

http://www.biofueldaily.com/reports/Researchers_report_novel_hybrid_catalyst_to_split_water_999.html

Researchers said the catalyst remained stable and effective through more than 40 hours of testing.

The new catalyst, they wrote, "proves to be an outstanding bifunctional catalyst for overall water splitting, exhibiting both extremely high OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) activities in the same alkaline electrolyte. Indeed, it sets a new record in alkaline water electrolyzers (1.42 V to afford 10 mA cm-2), while at the commercially practical current density of 500 mA cm-2."

This is a bit tangential but imagine if it became practical to produce hydrogen and oxygen on-site? Would liquifying it take an enormous amount of equipment?  I suppose you'd need a huge substation to provide the power.

Would it make any difference to the difficulty of handling these liquids onsite?

[john smith 19]

At the Westcott rocket propulsion conference Alan Bond was in the audience and he emphasised that SABRE4 was a family of engines so I presume they want to have a sort of made-to-measure situation.  I am not 100% sure but it seemed to me as if they wanted at least some of the components to be the same at for each member of the family but to merely use "more" for a larger engine.  I think my understanding is crude at best though.  I imagine that the proper sizing of everything to produce a useful range of "steps" in the scale would be critical and you'd want lots of data before you set things in stone.

Which AIUI is the point of the SABRE ground test engine currently in design.

[john smith 19]

As a general question is anyone going to Farmborough this year?


REL will be there

[t43562]

As a general question is anyone going to Farmborough this year?

REL will be there

I might be able to go on the public days. It might be worth getting a list of questions together.

[john smith 19]

As a general question is anyone going to Farmborough this year?

REL will be there

I might be able to go on the public days. It might be worth getting a list of questions together.

I'm very interested in the (loosely) talked about Flight Test Vehicle to follow on after the ground engine.

Renderings show something like the D-21 M3 drone but this had "Wet wing" tanks. A later attempt by NASA to implement a TBCC test vehicle using one put extended doughnut shaped LOX tank outside the engine duct.

But LH2 is much colder than LOX (and LOX would still be needed to test the air breathing/rocket engine transition) 

So my questions would be.
Is the single engine D-21 like layout still the baseline, or is this being revised?
If so, can you say what to?
Will it be LH2 powered, or will they use a higher BP fuel, like Methane?
Where will the fuel be stored?

Otherwise how is the design of the Ground Test Engine going?

[Stellvia]

As a general question is anyone going to Farmborough this year?

REL will be there

Yes, on the Saturday.

I note that UKSA will be staging a one-day "Launch UK" mini-conference at Farnborough on the Wednesday (18th): https://twitter.com/spacegovuk/status/1014448621360738306 (which I can't make, sadly :-()

[JCRM]

Not sure if this is quite the thread for it, but the excellent Interplanetary Podcast #86 has part 1 of an interview with Alan Bond on his fascinating career.  Part one loosely covers up to forming Reaction Engines, originally just with the intent of preserving the technology.

https://www.interplanetary.org.uk/episodes

Part 2 was in podcast #88, and had lots of interesting bits

* The D1 nacelle design had about half the curvature of the C1's 12 degrees [which suggests there may be a more recent D1 design than the detailed on in the Skylon 2.1 manual]
* REL now have functional designs for SABRE, intakes and Skylon, but
* the technology's  first applications are likely to be terrestrial for political reasons;
* the helium loop was first included to work around restrictions due to the patents he sold to Rolls Royce, but had a number of benefits - it reduced the issues due to the extreme non-linearity of hydrogen's SHC at 20K and the embrittlement problem, it also addressed the concern that a catastrophic heat exchanger failure could dump hot hydrogen into the rocket intake (but this wasn't something that had ever bothered him)
* under Willets, the UKSA was quite good, but has now lost its champion in the government so struggles.
* If only governments meant it when they said they were interested in disruptive technologies - as the UK has no investment in launch, it is is a good position to take advantage of Skylon disruptive nature.
* he still works about 30 days a year for REL.
* the airline model is still good, but doesn't know if anyone will invest in it because of long timescales and lack of certainty. It'll probably need government funding.
* Mark Thomas has changed the company into something the aerospace industry can take seriously.
* a big problem for the intakes is making them as inefficient as necessary while maintaining stable airflow
* a successful 2020 test will significantly change things.
* likely to go through a number of test vehicles to build confidence.
* building an 18000 hour heat exchanger for Lapcat A2 would be much harder than building a 50 hour Skylon one
* he's currently working on a design for an air-ionising electric engine capable of reaching 8km/s at 45 km (giving an apogee of 500km, an idea he shelved when HOTOL happened, coupled with a variable ISP plasma engine running off the same onboard fusion reactor to make an interplanetary, and possibly interstellar, space craft. He started a new company "Mirror Quark Limited" to work on this. It looks like he needs inertial electrostatic fusion reactors to pan out to make it work though.
* Elon Musk is a hero to him, for spending the money to break the old models. Thinks F9 and F9H are a good combination.

(a few corrections after a second and third listening)

[john smith 19]

The 2nd podcast is here

https://soundcloud.com/matt-interplanetary/88-alan-bond-part-2-csg

Interview starts around 18:10

One interesting factoid in the preamble was a discussion to the Guiana space port which mentioned the service tower for the Vega rocket weighs the same as the Eiffel Tower IE 7300 tonnes.

On wheels.

It's not surprising launch facilities are difficult to move when the infrastructure for a small rocket ( c1500Kg IIRC) is that big.

Another side shoot is his discussion (35:50) of a new company called "Mereaquark" (?) looking at the idea of applying MHD to vehicle propulsion. The issue being how to do ionization of the bulk airflow through the system and the power requirement. This is pretty exotic, although some fairly obvious directions suggest themselves.

[Elmar Moelzer]

This seems relevant:
https://www.wearefinn.com/topics/posts/the-engine-that-could-cut-london-australia-flight-time-to-45-hours/

[chipguy]

* he's currently working on a design for an air-ionising electric engine capable of reaching 8km/s at 45 km (giving an apogee of 500km, an idea he shelved when HOTOL happened,

Can it operate at altitudes lower than 45 km?

Nitrogen and Oxygen are a big pain to ionize even just enough to pass current
sufficient for MHD thrust generation. With high temp superconducting magnets
it must still be very power intensive to generate thrust this way. Energy source?

coupled with a variable ISP plasma engine running off the same onboard fusion reactor to make an interplanetary, and possibly interstellar, space craft. He started a new company "Mirror Quark Limited" to work on this. It looks like he needs inertial electrostatic fusion reactors to pan out to make it work though.

Wow that is really, really out there.

[edzieba]

* he's currently working on a design for an air-ionising electric engine capable of reaching 8km/s at 45 km (giving an apogee of 500km, an idea he shelved when HOTOL happened,

Can it operate at altitudes lower than 45 km?

Nitrogen and Oxygen are a big pain to ionize even just enough to pass current
sufficient for MHD thrust generation. With high temp superconducting magnets
it must still be very power intensive to generate thrust this way. Energy source?

ESA have already test-fired an air-breathing Ion engine, though that one is designed for 200km altitudes and orbital speeds.

[Asteroza]

Wasn't there a PDF floating around somewhere on NSF of an air ionizing turbo jet (MHD generator/air flow speed reducer, turbojet, then MHD accelerator) where they were exploring using e-beam ionization of air to energize the incoming flow enough for MHD ops? Apparently using an e-beam was a big improvement in ionization/plasma seeding.

[JCRM]

At some point in the last 3 months Orbital Access moved their site to the Wix site builder, and have a roadmap for how they see SABRE being used:

[john smith 19]

At some point in the last 3 months Orbital Access moved their site to the Wix site builder, and have a roadmap for how they see SABRE being used:

Well that is quite succinct.

If REL were planning a 4 year ground test programme that would sort of dovetail into flight testing the engine.

 

[john smith 19]

Is anyone going to Farmborough who could ask REL a few questions this year?

[Asteroza]

With the recent announcements about Cornwall Newquay airport becoming the new UK "horizontal spaceport", ostensibly to lure LauncherOne, might we see some facilities work at Newquay to support actual spaceplanes?

But, fitting in a 5 mile long runway would be a bit troublesome, looking at the map (with the main runway being about 10K ft?)

https://www.google.com/maps/place/50%C2%B026'27.0%22N+4%C2%B059'43.0%22W/@50.4391307,-5.0115616,10515m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d50.440833!4d-4.995278?hl=en

I suppose you might be able to extend the primary runway to the beach, but the people in Trevarrian/Tregurrian will not like you. The deactivated runway to the southwest, extended to the beach, might be another option but Newquay Resort would hate you.

Well, there's the former airbase just north at St. Eval, with the northwestern runway being the easiest to extend, if you can get the current Kart circuit to move...