Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 422194 times)

Offline francesco nicoli

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #560 on: 08/21/2015 05:49 PM »
Guys, a few questions that might be useful for an article I plan to write for my blog.

1) Someone said earlier in the thread that 30 people per passenger module is not viable anymore. Do you have different estimates?
2) how would Skylon perform by launching from the arab peninsula? the rationale is that:
- arabs have huge capitals
- arabs are looking actively for new ways to diversify  their oil-based economy
- they already have a very high end turism sector, which could be a perfect complement for a manned Skylon
- they are not so distant from equator


any tought?

Offline Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #561 on: 08/21/2015 07:48 PM »
@Francesco
People who would potentially pay to go into orbit as a tourist will want to look out the window. Having super Hi-Def internal screens or VR headsets to show what's outside isn't going to cut it for these people, otherwise they could just look at a screen on the ground. Having windows would completely alter the structural integrity of Skylon. Skylon therefore isn't going to be used as a tourist operation. Something else that uses SABRE technology might, but for the moment all that we've ever heard from REL is SABRE/Skylon.
« Last Edit: 08/21/2015 07:49 PM by Citizen Wolf »
The only thing I can be sure of is that I can't be sure of anything.

Offline RonM

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #562 on: 08/21/2015 08:01 PM »
@Francesco
People who would potentially pay to go into orbit as a tourist will want to look out the window. Having super Hi-Def internal screens or VR headsets to show what's outside isn't going to cut it for these people, otherwise they could just look at a screen on the ground. Having windows would completely alter the structural integrity of Skylon. Skylon therefore isn't going to be used as a tourist operation. Something else that uses SABRE technology might, but for the moment all that we've ever heard from REL is SABRE/Skylon.

Tourists wouldn't be able to look out a window during takeoff and landing. However, once Skylon is in orbit and the payload bay doors are open, there is the opportunity for very large windows in the passenger module and a magnificent view.

Offline lkm

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #563 on: 08/21/2015 10:53 PM »
Ok, so if we're posting numbers now I might as well post mine.
I make the tail area affected by the rocket plume to be approximately  99m2 based on the tail modelled as a Sears-Haack body, which it isn't perfectly, and the thermal image from the paper at Mach 16, which only shows the top and could be larger area than that  at higher altitude.
 
Okay so now things get more  hand wavy and I make no guarantee my maths is right, but the SABRE engines put out  about 6.9Gw with a mass flow of 666 kg. If you imagine that energy spread over the surface area of  cones moving back from the engines then the proportion of the energy intersecting with the tail could be said to be the area of the tail affect/the area of the cones. If that's the case then the tail might be seeing something like 3.3kw/m2 which over the 195 seconds from Mach 8 to orbit could raise the temperature of the skin by around 860K on top of the aerodynamic heating which tops out at 855K for certain parts of the fuselage skin. This is all hand wave and BOE stuff but it seems like a reasonable number. A peak of 1715K might seem bad but the tail probably doesn't seem that much aerodynamic heating and it seems managable with some active cooling or C/SiC. 

Also Skylon carries 1200kg of water for the brakes.                                                                                                               

Offline Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #564 on: 08/21/2015 10:55 PM »
@RonM
I guess there is that possibility. But before that happens Skylon will have to become human rated. That might be a little ways off yet.
The only thing I can be sure of is that I can't be sure of anything.

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #565 on: 08/21/2015 11:59 PM »
Ok, so if we're posting numbers now I might as well post mine.
I make the tail area affected by the rocket plume to be approximately  99m2 based on the tail modelled as a Sears-Haack body, which it isn't perfectly, and the thermal image from the paper at Mach 16, which only shows the top and could be larger area than that  at higher altitude.
 
That's about 2/3 of my worst case area estimate.
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Okay so now things get more  hand wavy and I make no guarantee my maths is right, but the SABRE engines put out  about 6.9Gw with a mass flow of 666 kg. If you imagine that energy spread over the surface area of  cones moving back from the engines then the proportion of the energy intersecting with the tail could be said to be the area of the tail affect/the area of the cones. If that's the case then the tail might be seeing something like 3.3kw/m2 which over the 195 seconds from Mach 8 to orbit could raise the temperature of the skin by around 860K on top of the aerodynamic heating which tops out at 855K for certain parts of the fuselage skin. This is all hand wave and BOE stuff but it seems like a reasonable number. A peak of 1715K might seem bad but the tail probably doesn't seem that much aerodynamic heating and it seems managable with some active cooling or C/SiC. 
Another data point may put this number in perspective.

Heat energy released by a modern microprocessor is roughly 100 W/cm^2
As was the thermal rating of the Apollo heat shield.

That's 1 MW/m^2 (laptops use some pretty complex thermal management methods to spread that load so you can (in theory) rest them on you lap and not find scorch marks on  your trousers afterward.

3.3 Kw/m^2 sounds quite viable.


@RonM
I guess there is that possibility. But before that happens Skylon will have to become human rated. That might be a little ways off yet.
Perhaps not as far as you think.

Skylon is completely reusable. What's tested in certification is what will fly. Exactly what was tested, not a new piece built to the same design.

REL have also stated they have no plans to mfg a passenger module however they will accommodate one in the test flights during development if someone builds such a module.

If the flight programme runs 400 flights and the passenger module flies 10 of them and none of them results in a crash would you feel fairly confident the next flight with the module would not either?

Would you feel the same wasy if half the vehicle was newly built and this was its first flight?
"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 Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #566 on: 08/22/2015 12:53 AM »
Regarding the whole rocket plume and the back end of Skylon - any chance of anyone from REL letting us know if this has been looked at and whether it's expected to be a problem?
The only thing I can be sure of is that I can't be sure of anything.

Offline Hanelyp

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #567 on: 08/22/2015 06:24 PM »
... If that's the case then the tail might be seeing something like 3.3kw/m2 which over the 195 seconds from Mach 8 to orbit could raise the temperature of the skin by around 860K on top of the aerodynamic heating which tops out at 855K for certain parts of the fuselage skin. This is all hand wave and BOE stuff but it seems like a reasonable number. A peak of 1715K might seem bad but the tail probably doesn't seem that much aerodynamic heating and it seems managable with some active cooling or C/SiC.
3.3kw/m^2 isn't all that much.  Presuming the tail surface was heated by some other source to 855K (and the heat sink calculator I'm using is accurate) that come out to in the neighborhood of 30 degrees extra heating when you account for radiative cooling.  885K doesn't need active cooling with the right materials, or even really exotic materials.

Offline lkm

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #568 on: 08/22/2015 11:42 PM »
... If that's the case then the tail might be seeing something like 3.3kw/m2 which over the 195 seconds from Mach 8 to orbit could raise the temperature of the skin by around 860K on top of the aerodynamic heating which tops out at 855K for certain parts of the fuselage skin. This is all hand wave and BOE stuff but it seems like a reasonable number. A peak of 1715K might seem bad but the tail probably doesn't seem that much aerodynamic heating and it seems managable with some active cooling or C/SiC.
3.3kw/m^2 isn't all that much.  Presuming the tail surface was heated by some other source to 855K (and the heat sink calculator I'm using is accurate) that come out to in the neighborhood of 30 degrees extra heating when you account for radiative cooling.  885K doesn't need active cooling with the right materials, or even really exotic materials.
Yeah it's a really reasonable number, which is why I was so equivocal about it.
 I calculated it from what seems like an intuitively simple picture of what's going on but the reality must be much more complicated and, as you say, once you factor in radiative cooling then the rate of cooling at 800K is something like 20kw/m2, which basically would make it a non issue which is why I'm somewhat doubtful that there's not something wrong with that number.

Offline Lars-J

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #569 on: 08/28/2015 07:00 AM »
@RonM
I guess there is that possibility. But before that happens Skylon will have to become human rated. That might be a little ways off yet.
Perhaps not as far as you think.

Skylon is completely reusable. What's tested in certification is what will fly. Exactly what was tested, not a new piece built to the same design.

I'm sorry to inject some reality here, but Skylon is actually none of that, because it does not exist. (yet?) It has not passed a final system design review, no flight hardware has been built, no flight has occurred. It may be *planned* to be completely reusable, but that can be a different thing altogether.

You have more absolute faith in Skylon specifications that REL engineers themselves do.
« Last Edit: 08/28/2015 07:01 AM by Lars-J »

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #570 on: 08/28/2015 01:29 PM »
It may be *planned* to be completely reusable, but that can be a different thing altogether.
I see it's been a while since I mentioned that SABRESkylon is a high cost/risk/reward programme.  Anyone who does not realize this should study the programme more closely.

Like other vehicles it could fail to deliver on it's stated design objectives, much as the X33 and F9R have done.

Unlike both vehicles it's shape is close to that of vehicles that have a)Been designed 1000s of times before (aircraft) and broadly similar to the only 3 designs that have made winged re entries to Earth and the only 2 designs that has made repeated re-entries to Earth (the 2nd being the X37b).

Unlike those vehicles it's trajectory (or flight path for aircraft) is also quite similar to designs  that have flown from runways millions of times before.

All of which suggests (but does not guarantee) That provided the materials deliver their specific properties and the engines deliver their Isp  all "unknown unknowns" will be manageable, as you're (loosely) trying to extend an existing architecture (in terms of shape, flight path and speeds), rather than do a step change on an architecture that was never designed to be reused in the first place.

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You have more absolute faith in Skylon specifications that REL engineers themselves do.
Again not in the sense you seem to mean.  :(

Those who've followed the programme know that in fact Skylon is in it's 4ths re-design (5th if you include HOTOL) as REL have become more detailed in their modelling and more knowledgeable. They have been fortunate that their thinking converged on a design that has not needed radical re-design since originally conceived.

I have absolute faith that both the Reaction Engines and SpaceX design teams will do their very best to make their approaches work.

I have absolute faith both will use the best available models and modelling tools to ensure their plans are viable, or to scrap them and re-design their architecture if they cannot deliver the expected results.

What do you have absolute faith in?
"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 Lars-J

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #571 on: 08/28/2015 03:28 PM »
I have absolute faith both will use the best available models and modelling tools to ensure their plans are viable, or to scrap them and re-design their architecture if they cannot deliver the expected results.

I'm glad to hear it, because that is not how you come across when posting.

What do you have absolute faith in?

That change is a constant. And assumptions are often wrong. Among other things. ;)

But in regards to Skylon - based on aerospace history - I have faith in that *IF* Skylon ever flies, it will have some significant differences to the current evolution of the design.

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #572 on: 08/29/2015 07:34 AM »
I'm glad to hear it, because that is not how you come across when posting.
Like everyone else on any forum, I am responsible for what I write, not for how people read it.

My model for behavior remains Henry Spencer, whose posts always remained polite as well as informative, sometimes in the face of considerable provocation.

Sadly I do not always maintain his high standards.  :(
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That change is a constant. And assumptions are often wrong. Among other things. ;)
Indeed, if you "assume" you do tend to make an ass out of you and me, as the saying goes.  :)
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But in regards to Skylon - based on aerospace history - I have faith in that *IF* Skylon ever flies, it will have some significant differences to the current evolution of the design.
The industry does have a history of over promised specs, under developed tech and under-performing (or non existent, even after $Bn investments) hardware. It is also a truism that key top level design decisions can make or break a project.

The X30 and X33 programmes being master classes of all of those aspects. An SCRamjet engine that after 40+ years of development manages a T/W of about 2? No checking that correct values for certain physical constants were entered correctly?

Let me be clear so you do understand my PoV.

My interest is in anything that lowers the cost per unit mass to LEO in a scaleable  way. The argument "Just launch a 100 tonnes and the price will drop" is pretty much useless to me, since right now most people don't want or need this. It's the same argument used for Ariane 5, Saturn V and SLS (or Ares 5 for it's old name). It only works if the launch rate justifies the up front costs, because it's generally the up front costs that are a nightmare.  I don't know what Areas 5/SLS has spent to date but I do know what' it's put into LEO.

The "We'll cut the cost by 1/2" figure (often touted at start of ELV development) was viewed as useless in the 1950's by Arthur Snitt. I don't expect any change in the market without an 80-90% price cut in the multi tonne to orbit. If you're going to do it I think doing it and having no down mass capability (IE Antares) is pretty much a waste of time. The world does not need yet another  ELV (or semi ELV, which is also what the Shuttle was) with no track record.

I don't care how it's done. I do care if the claims, and how they are planned to be carried out fail even simple cost models. 

The fully reusable F9 looked like it might achieve this 10x reduction. Just to inject some reality here but the first 1st stage F9 recovery has still not happened yet and the architecture will not achieve that price goal for a semi reusable unless SX already mfg F9's with colossal profit margins, IE 200-250% of F9 hardware price.

I think people would have remarked on such an ability, as I don't think it's the normal gross profit margin in aerospace.  :(

I like Skylon because it's developers seem to have factored in the big picture.

It's the only reusable concept that plans to deliver what an equivalent sized ELV can do, does not require the launch provider to carry all the development costs directly (but only because it's designed for full reuse), is sized for the known market and basically gives solid financial reasons for investing in it other than the vanity of the investor.

As a side point when fully funded the team have delivered what they said they would deliver when they said they would deliver it. This is also attractive to investors who are not governments, although it is a reason governments should also invest.

I am equally impressed by XCOR, who have had endured similar trials on their development path and I'd like to see more like all three, but I simply don't. They seem to be the only ones with serious ambition to get to orbit. :(
"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 pippin

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #573 on: 08/29/2015 02:17 PM »
Aren't you contradicting yourself a bit here? If the upfront costs are the problem the RLVs generally look bad, Skylon included.
That's also the reason why there was no way in the world a fully reusable F9 could ever have reduced the launch costs by a factor of 10, the fixed costs are still too high. 50%, maybe, 10% nope.

And that Skylon fudge to split up the business case also won't help, it just moves part of the financial uncertainty beyond the event horizon so that it can easily get forgotten. Problem just is that that doesn't mean it's going away the same way that sticking your head into the sand doesn't make the Lion go away.

Offline 93143

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #574 on: 08/29/2015 09:11 PM »
The problem they're trying to solve is not the fundamental economic viability of the vehicle.  The problem is getting investment to cover the large up-front development cost.  Balancing that with a relatively near-term payout means the problem of flight rate is pushed off onto operators, who already know the vehicle works once they're called upon to make their decision.  The problem of slow payback is separated from the risk of programmatic failure, which makes the initial investment more attractive.

This is in addition to the distinct possibility that state actors and even some non-governmental entities may well want Skylon for its other characteristics even if they don't necessarily expect to use it often enough to save any money.  And if I recall correctly, REL did say something about selling their first run to government agencies at a higher price, and then dropping the price later for commercial operators...
« Last Edit: 08/29/2015 09:52 PM by 93143 »

Offline pippin

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #575 on: 08/29/2015 10:36 PM »
The problem they're trying to solve is not the fundamental economic viability of the vehicle.

Yes, but that's a totally separate point from the one I was making.
I was talking about the launch cost.

Launch cost has almost nothing to do with development cost, at least not for any "breakthrough" development e.g. technology development (ongoing development costs for things like continuous improvement, adaptation for new requirements etc. are a separate issue and are more like operating costs because they are recurring).
These development costs are sunk costs after the initial development and have no impact on the operating costs and flight costs. Yes, they can ruin your business case (especially overruns) and yes _prices_ may be set pretty high in a hope to recover some of that investment but on the actual launch cost they have no impact.

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #576 on: 08/29/2015 11:51 PM »
Aren't you contradicting yourself a bit here? If the upfront costs are the problem the RLVs generally look bad, Skylon included.
I was referring to the up front costs of an ELV 4x-5x bigger than the biggest members of the EELV programme.
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That's also the reason why there was no way in the world a fully reusable F9 could ever have reduced the launch costs by a factor of 10, the fixed costs are still too high. 50%, maybe, 10% nope.
And that's the issue when the builder is the operator as well.
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And that Skylon fudge to split up the business case also won't help, it just moves part of the financial uncertainty beyond the event horizon so that it can easily get forgotten. Problem just is that that doesn't mean it's going away the same way that sticking your head into the sand doesn't make the Lion go away.
And yet that "fudge" is exactly how every other transport system on this planet does business.  :(

While it's true that the way things have been done is not necessarily a good reason for doing it that way in the future the fact that no one else does it the same way it's interesting that ship yards don't run cruise lines, aircraft mfg's don't run airlines (even in countries where this does not break anti-trust laws) or 18 wheeler mfg run haulage companies.

Should that not give people pause for thought that perhaps the way the rocket industry does things is a bit odd and needs to change?
"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 Impaler

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #577 on: 08/30/2015 03:21 AM »

While it's true that the way things have been done is not necessarily a good reason for doing it that way in the future the fact that no one else does it the same way it's interesting that ship yards don't run cruise lines, aircraft mfg's don't run airlines (even in countries where this does not break anti-trust laws) or 18 wheeler mfg run haulage companies.

Should that not give people pause for thought that perhaps the way the rocket industry does things is a bit odd and needs to change?

In the early days of airplanes and ocean liners that IS what happened, Boeing for example used it's superior designs to run a very anti-competitive airline, government action forced them to stop (and they are still a notorious corrupt company).  The WhiteStar ocean liner company was in a partnership with Harland and Wolff shipbuilders who agreed to not make any ships for WhiteStar's competitors.

The division of manufacturer and operator is always associated with a transportation system becoming, cheap, common, safe, reliable, competitive and regulated.  I don't think anyone disputes that WILL eventually how space travel is done the question is if this vehicle would achieve that kind of market transformation.  Skylon would need to make quantum leaps in all these areas before the ground would be ready for an airliner like division between manufacturer and operator.  It will probably also require a second company making competing substitute vehicles as no operator would run the risk of being completely dependent on a single vehicle supplier.


P.S.  On a technical note, dose anyone think a closed wing https://en.wikipedia.org/wiki/Closed_wing#PrandtlPlane_.28Box-Wing.29 configuration would help Skylon, it would seem to present the possibility of both reducing drag while allowing a higher mounting of the engines thus reducing the need for the bent nacelle (which I assume is needed to keep the thrust through the center of mass which is above the nacelle).
« Last Edit: 08/30/2015 03:23 AM by Impaler »

Online john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #578 on: 08/30/2015 08:31 AM »
In the early days of airplanes and ocean liners that IS what happened, Boeing for example used it's superior designs to run a very anti-competitive airline, government action forced them to stop (and they are still a notorious corrupt company).  The WhiteStar ocean liner company was in a partnership with Harland and Wolff shipbuilders who agreed to not make any ships for WhiteStar's competitors.
Note that word partnership None of the examples you cite were as tightly integrated between the mfg and the operator as most current ELV mfg's are. IIRC TWA and Boeing aircraft were part of the same holding company as was Hamilton Standard (propellers at the time).
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The division of manufacturer and operator is always associated with a transportation system becoming, cheap, common, safe, reliable, competitive and regulated. 
Over a long time scale and that process has barely begun.
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I don't think anyone disputes that WILL eventually how space travel is done the question is if this vehicle would achieve that kind of market transformation. 
Why? [EDIT IOW What pressures are driving that "transformation."  If you're talking about governments in terms of "Get rid of ELV's and lower our launch costs 10x now" the answer is nobody ]

The status [EDIT to be clear I mean the status quo] keeps the people who can already justify launching satellites (or get some government to fund them) launching things already.  As for everyone else they can't afford to launch so (basically) they don't count the the main ELV mfg mind set really could not care less.
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Skylon would need to make quantum leaps in all these areas before the ground would be ready for an airliner like division between manufacturer and operator. 
Depends what you mean by "quantum."

A vehicle that a)Lasts for more than 1 use and b)Does not need have it's structure rebuilt or replaced every time it's used is SOP for every other transport system on the planet, certainly for anything that can move multi tonne weights over 200Km.

Historically people seem to have been thinking that you can gradually evolve to full reusability but SX have demonstrated that does not work. It's a Sow's ear. You can (sort of) make it into something that will hold stuff. It will never be a ladies evening bag for social events.
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It will probably also require a second company making competing substitute vehicles as no operator would run the risk of being completely dependent on a single vehicle supplier.
Hmm. Let me see. I am a government that wants to launch payloads into space on a semi regular basis. Do I
a) Keep handing $60-150m to a foreign business for a ticket with a roughly a 1 in 50 to 1 in 75 chance of being blown to bits that will launch it at their convenience
or
b) Commit to paying quite a lot more (but potentially spread out over a decade or more, roughly $150m/year or 1/120 of NASA's budget) for a vehicle that can launch more or less when we want it to (since it's preped in our country, self ferries to the Equator, get a top up and goes), carries our payload as prime and for a bit extra can give us an upper stage that will allow us to run a Moon or planetary exploration programme.

As a side benefit we can also sell excess capacity to other customers while new projects are in development and if we so choose sell it as an asset (the nearest people come to this is selling either the data from satellites they own or the orbital slots for GEO comm sats)

Decisions, decisions.

BTW this sounds like a discussion US customers would be barred from, but there's nothing to stop a US operator (or part of the US government) buying a Skylon. The real issue would probably be that under US ITAR laws flying down to the Equator would be viewed as "exporting" the payload, even if the Skylon were USG property and therefor (technically) US territory (like Air Force One) and it was simply refueled and loaded with LO2 before take off to orbit.  :(
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P.S.  On a technical note, dose anyone think a closed wing https://en.wikipedia.org/wiki/Closed_wing#PrandtlPlane_.28Box-Wing.29 configuration would help Skylon, it would seem to present the possibility of both reducing drag while allowing a higher mounting of the engines thus reducing the need for the bent nacelle (which I assume is needed to keep the thrust through the center of mass which is above the nacelle).
No. because the heating issue is about plume impingement on the rear fuselage. Your suggestion "fixes" what is currently a non issue as it already has a solution.

What it might address is how to make the next generation of airliners bigger than the 777 or A380. So far the front runner seems to be the Blended Wing Body concept, but this basically eliminates window seats. I don't have an problem with this but apparently people want window seats and the Prandtl design lets them have them, while (in theory) lowering the drag and raising the lift for a given wingspan, which is apparently limited in modern airport design to 80m, and nobody is going to redesign the layout of most of the worlds large airports anytime soon.

That would be a topic for another thread.
« Last Edit: 08/31/2015 10:51 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 pippin

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #579 on: 08/30/2015 02:59 PM »

And yet that "fudge" is exactly how every other transport system on this planet does business.  :(

Im not saying it's wrong to operate that way. If REL think it's the way to go for them then there is no reason not to use this model - as long as they can find customers.

What I'm saying is that it's not some kind of fairy dust which magically removes a huge amount of cost just by splitting up the business model.

Can you work this way? If you find customers, sure you can.
Can it help to raise mor funds for the overall business? Maybe.
Will it be dramatically cheaper? Nah.

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