Reaction Engines SABRE engine (Skylon Spaceplane)

just musing, have there been any further information released showing the test vehicle in which the intended 'first flight' is to be achieved ?

cheers, Joe
 
TsrJoe said:
just musing, have there been any further information released showing the test vehicle in which the intended 'first flight' is to be achieved ?

cheers, Joe
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Full cycle ground based demonstrator first with propulsion elements as well as heat exchanger.

Not really much existing that you could bolt one of these engines to and see what happens over the entire flight envelope.
 
TsrJoe said:
have there been any further information released showing the test vehicle in which the intended 'first flight' is to be achieved ?
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Their website states that "There are three core building blocks to the SABRE engine, the pre-cooler, the engine core and the thrust chamber. ... We have demonstrated each of these independently over the last four years." Another page adds that "... will culminate in full system testing in 2020, at which point the world’s first air-breathing engine capable of accelerating from zero to Mach 5 will have been demonstrated."
That is all ground-based. The new funding takes off from there. There are certainly few if any unclassified airframes capable of sustaining Mach 5 flight for long enough without breaking up or melting, so likely we will see rather more pedestrian flights to start with and there are a good many opportunities there. I would hazard that whatever sponsors come forward in the new funding round might have something to say about whose plane/s they bolt it to and at what speed/s.
 
steelpillow said:
TsrJoe said:
have there been any further information released showing the test vehicle in which the intended 'first flight' is to be achieved ?
Click to expand...

Their website states that "There are three core building blocks to the SABRE engine, the pre-cooler, the engine core and the thrust chamber. ... We have demonstrated each of these independently over the last four years." Another page adds that "... will culminate in full system testing in 2020, at which point the world’s first air-breathing engine capable of accelerating from zero to Mach 5 will have been demonstrated."
That is all ground-based. The new funding takes off from there. There are certainly few if any unclassified airframes capable of sustaining Mach 5 flight for long enough without breaking up or melting, so likely we will see rather more pedestrian flights to start with and there are a good many opportunities there. I would hazard that whatever sponsors come forward in the new funding round might have something to say about whose plane/s they bolt it to and at what speed/s.
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I thought they were going to build a purpose constructed flight demonstrator not use an existing airframe.
 
Flyaway said:
I thought they were going to build a purpose constructed flight demonstrator not use an existing airframe.
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Yes, for the hypersonic tests, surely so. But for lower flight speeds there are plenty of existing candidates bumbling about the sky and running out of things to do. If I were Reaction Engines, I would want to flight-test SABRE's basic operation and low-level performance before I stuck it in an expensive one-off optimised for Mach 5. Much as R-R hung the civil Olympus under an old Vulcan before sticking it in Concorde.
 

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Awful. Although might appeal to the gay community...


*without any disrespect. Just to pass the idea while avoiding vulgar language.
 
TomcatViP said:
Awful. Although might appeal to the gay community...


*without any disrespect. Just to pass the idea while avoiding vulgar language.
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Imagine the headline:

Skylon to launch a probe to Uranus...

 

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It doesn't look like there is much room for cryogenic fuel tanks in these concepts!
 

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SteveO said:
It doesn't look like there is much room for cryogenic fuel tanks in these concepts!
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Not sure where the demonstrator puts its undercart either, unless the thing is disposable which seems to undermine the whole point of SABRE.

On the other hand the operational spaceplane presumably has its fuselage filled with hydrogen except for a teensy payload bay. Hope the canard foreplane doesn't melt.
 
The SABRE engine
steelpillow said:
SteveO said:
It doesn't look like there is much room for cryogenic fuel tanks in these concepts!
Click to expand...

Not sure where the demonstrator puts its undercart either, unless the thing is disposable which seems to undermine the whole point of SABRE.

On the other hand the operational spaceplane presumably has its fuselage filled with hydrogen except for a teensy payload bay. Hope the canard foreplane doesn't melt.
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Wonder why they designed it with canard foreplane's? it seems rather stupid (unless they can retract the canard's at some point during the flight)
 
FighterJock said:
Wonder why they designed it with canard foreplane's? it seems rather stupid (unless they can retract the canard's at some point during the flight)
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I think it must be a response to the NASA study which slammed Skylon for burning up the tail in the rocket exhaust. They have very sensibly moved the engines back, as had originally been done with HOTOL, but would have promptly ended up with the same problem of a nose-heavy plane when fully laden. B.Ae blew hot and cold on adding canards to correct the imbalance in different iterations of HOTOL, I guess we are seeing the same approach here.
It might pay to make them retractable, Tu 144 style, once the bow tank has been emptied during initial subsonic climb to altitude. On the other hand, if the economics work best with a fast transistion to supersonic climb before significant fuel is burned, then fixing them in place could be a better bet.
 
A better summary might be that the airframe concept hasn't really matured since the 1980s. They're still searching for a viable configuration on which to integrate their engine. Hence the removal of any technical content on airframes from their site and replacement by PR images.

If you can't viably integrate airframe and engine together then there's no point.
 
I don't think that is a showstopper. Viable configurations are known and are evolving all the time and Reaction Engines have learned the hard way to stick with the experts. The problems are more about mission profiles and cost-effective choice of technology levels - both of which depend on your predicted customer base. Personally I'd hope to see the long fuselage strakes of the Lockheed Blackbirds (which were basically flying fuel tanks and, given a zoom-climb to peak altitude, would have come close to being suborbital spaceplanes).
 
steelpillow said:
I don't think that is a showstopper. Viable configurations are known and are evolving all the time and Reaction Engines have learned the hard way to stick with the experts.
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Which configurations? So far nothing has worked e.g Skylon dropped.

Stick with the experts? REL build high temperature heat exchangers. They don't have experience of detailed design or build or operation of air/spacecraft.
 
Not so sure about the “nothing has worked statement”. RE moved away from Skylon when Alan left and BAe took over. It was more of a company strategy decision rather than a bin it cause it won’t work.I’m not even sure the NASA work said it was a show stopper, from memory it described it as challenging but might be overcome with the right approach. Then there was the Strathclyde University revised Skylon configuration which was developed with the rear fuselage issue in mind but was never (at least to my knowledge) evaluated by NASA.
 
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@red admiral:

The conventionally-configured X-15 was a successful two-stage spaceplane. The tailless compound-delta-winged Space Shuttle was vertically launched, while the V-tailed compound-delta-winged X-35 is also vertically launched and still in service. These configurations have all been proven, there and elsewhere, in all phases of the SSTO flight envelope. Even the outboard tail configuration of SpaceShips One and Two has been repeatedly proven in the lower-altitude SSTO flight regions by various experimental prototypes. So it is quite wrong to claim that "so far nothing has worked". If you just mean that no SSTO has yet made it into space, I think we already know that.

Of course, when I write that "Reaction Engines have learned the hard way to stick with the experts" I mean that their Skylon blunder taught them to look elsewhere for proper experts in air/spacecraft design. Note that, to this end, they have put the design of the demonstrator aircraft out to tender. Given these simple facts, I am puzzled what else you might have read into my remark.
 
steelpillow said:
SteveO said:
It doesn't look like there is much room for cryogenic fuel tanks in these concepts!
Click to expand...

Not sure where the demonstrator puts its undercart either, unless the thing is disposable which seems to undermine the whole point of SABRE.

On the other hand the operational spaceplane presumably has its fuselage filled with hydrogen except for a teensy payload bay. Hope the canard foreplane doesn't melt.
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Could they be looking at magnetic landing systems, like the Soviets were during the '80s?
 
We had a thread on it somewhere, I'll see if I can find it.

EDIT: Here we go. The MiG bureau's magnetic runway system, which was being developed for the Soviet Navy. Thought there was more detail about the system in the thread, but my memory may be playing tricks on me there.
 
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red admiral said:
Which configurations? So far nothing has worked e.g Skylon dropped.
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By thier own admission "Skylon" was always mostly a place-holder for REL until someone with a better concept came along. The Skylon was highly simplified in aerodynamics so thatmore focuse could remain on the engines.

Steelpillow is quite correct in that there are pretty much thousands of 'basic' zero-to-hypersonic configurations that could be used with the engines if they can be integreated into the design. Right now testing and proving the concept in flight is probably the main issue as that will help flesh out the actual data from the infered data which itself will help define what kind of airframe is best for the concept.

Randy
 
Grey Havoc said:
Could they be looking at magnetic landing systems, like the Soviets were during the '80s?
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Well, that would be a step ahead of the rubber trampoline the Royal Navy put up on an aircraft carrier and then landed a de Havilland Vampire on.
 
I'd consider the new design as a placeholder, but remember that Skylon was an SSTO whereas this new design is the first stage of a 2STO, so its tanks will be smaller and it doesn't have to re-enter at Mach 25.
 
Flyaway said:
arstechnica.com

The rocket motor of the future “breathes” air like a jet engine

This theoretical engine could drastically reduce the cost of getting to space.
arstechnica.com arstechnica.com
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Interesting. Their company website is cagey about how the thing works: https://www.marsengines.com/MEET-FENRIS/
so hard to say how it compares with SABRE. Certainly appears a lot simpler, but one wonders a) how they get enough air in for takeoff thrust and b) how they keep things cool for Mach 3 plus airspeeds.
 
How do they do with plume expension to prevent the ram air stream to get chocked? Is there any variable geometry?
(I had only a quick look at your excellent document).
 
While the ammonia jet engine is surely feasible in engineering terms, I have other doubts about its practicality:

Ammonia is pretty toxic in its own right, while gasoline is only moderately so. Although it is less flammable than gasoline, it is far more caustic; you really do not want it in your lungs for example. Because of this, localised ammonia storage has a lot more safety red tape than gasoline, you can't just fill up a plastic can and stick it in the back of your car. A cloud of gasoline fumes rolling over your town will cause more harm from the additives than from the gasoline fumes, but the same cannot be said for ammonia. The stuff was even used as a poison gas during WWI, though it was admittedly not very effective in the field. So the idea expressed by one of us here that the two are comparable is sadly misguided. Engineering failure and crashability will be interesting topics for the certification authorities, while the cost of safe bulk storage close to the travelling public (wrt both accident and terrorism) will impact the economics.

"perhaps some nitrogen oxides — although the latter can be removed from the exhaust using more ammonia." Really? Nitrogen oxides are nasty pollutants, being both toxic and greenhouse; one of the great political criticisms of Diesel cars over petrol is their nitrogen oxide emissions. Are we really being led to believe that these nasty substances can be scrubbed from ammonia exhaust to residual levels lower than Diesel exhaust and that the added ammonia will not cause a worse problem?

Then there is the thermodynamic cycle. It is well known that cooling the intake mixture of a combustion engine, be it jet or piston, increases its efficiency. This thing has a pre-heater! Will the cracked mixture be re-cooled before burning? We are not told outright and it is absent from the diagram, but it better be or the efficiency will be lousy. Reaction Engines may be good at adding more heat exchangers as occasion demands, including some pretty nifty pre-coolers, but it does put the costs up something shocking.

Ammonia has been used as a fuel on occasion, experimentally and in desperate times for motor vehicles, sometimes as the least vile option for rockets, and also at least proposed (though I am not sure of it was ever used) as a lifting gas for balloons and airships. IMHO the ammonia jet will go the same way as the ammonia airship and the ammonia ground vehicle - into the Great Home of Appallingly Bad Ideas in the Sky.
 
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