Author Topic: The Reaction Engines Skylon Master Thread (2)  (Read 587427 times)

Offline ukrocketman

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1660 on: 11/08/2013 11:33 PM »
Yes, but I would probably end up walking with a limp as a result of saying ;-)

It will certainly answer a few questions that have been asked on this thread though.
Intriguing.

I think VALKYRIE will also be the first REL project name that is not an acronym (at least I don't think it's one  :) )

You are, as usual, correct :-)  It isn't an anacronym, it isn't a rehash of the XB70 (I wish it was), and it isn't "Vehicle for Demonstration of Skylon Readiness".

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1661 on: 11/09/2013 10:51 AM »
Excluding "Skylon" of-course...
True. I was going to add acronyms only applied to their engine projects but then I remembered Project TROY for their Mars mission architecture study.

You are, as usual, correct :-)  It isn't an anacronym, it isn't a rehash of the XB70 (I wish it was), and it isn't "Vehicle for Demonstration of Skylon Readiness".
Well as others have pointed out Skylon isn't an acryonym either.  :)

While the XB70 was (and is) a stunning looking aircraft, and its construction method would be more viable today, it's performance is still less than 1/9 what Skylon needs (and will hopefully deliver). I'd love to see someone pitch the method for the new DARPA XS-1 programme but I just don't think theirs anyone left in the US with the capacity to implement it within the budget.  :(

I'll admit "Vehicle for Demonstration of Skylon Readiness" sounded good  :) but that slot should be taken by the first Skylon prototype, which I tend to think of "Skylon X," with the refined 2nd prototype being the orbit capable "Skylon Y," although I'd like to think REL are being conservative here and the 1st vehicle will achieve orbit.

While I suspect REL is closer to working with an airframe partner I think they are still a long way from beginning fabrication on that vehicle.  :( I know Hempsell (and others) has mentioned samples of the skin material and I wonder how far they have evaluated structural assemblies. Unfortunately given REL's fondness for full scale sub modules that would be quite big  :) A fuselage segment wold need a 2 storey bay to accommodate comfortably, including hardware to apply loads.  :(

I don't think the assembly issues should be underestimated either. There are a lot of struts to be assembled and I think there is a case for automated assembly, even of the prototypes. The benefit would not necessarily be speed, but consistency. A slow assembly system could run until it ran out of parts, long enough till the following day for example, although weekends might be a problem.  :)
« Last Edit: 11/09/2013 10:52 AM by john smith 19 »
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Offline Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1662 on: 11/09/2013 01:23 PM »
Validation Demonstrator for Skylon Rocket
or
Validation Demonstrator for Sabre Rocket
« Last Edit: 11/09/2013 01:24 PM by Citizen Wolf »
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Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1663 on: 11/09/2013 04:13 PM »
True. I was going to add acronyms only applied to their engine projects but then I remembered Project TROY for their Mars mission architecture study.

TROY was apparently so-named for REL employee Helen (who's middle name is not "Of"), who suggested the study.  :)
« Last Edit: 11/09/2013 04:14 PM by SICA Design »

Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1664 on: 11/10/2013 08:59 PM »
Many thanks to Rochelle (UK Space Environments Conference Organiser) for her kindness in allowing me to join as a (very) late delegate.

I can now reveal what Valkyrie/VDSR is all about (and, unlike ukrocketman, without fear for my legs - thanks Mark!).

Firstly Valkyrie:

This will be a small rocket, designed as an instrumented flying test-bed for plug-nozzle (e.g. STRICT, STERN) research and development.

It is designed to follow the velocity/altitude profile of Skylon (within 10%) and use an unusual tri-propellent mixture of nitrous oxide, ammonia and... liquid nitrogen!

The LN2 acts as a coolant and, crucially, allows the exhaust products to match those of SABRE in air-breathing mode.

Secondly VDSR:

This is a working-title for Valkyrie-Derived Sounding Rocket, an opportunity to capitalise on the design effort in Valkyrie, by producing a commercial sub-orbital rocket capable of lifting a small (10-20kg) payload to an altitude of 120-160km.

This will use a more-conventional fuel mixture of LOX/kerosene, keeping the same:

- pressure system
- tank diameter
- launch system
- solid rocket boost stage

This would have similar capabilities to the UK Petrel sounding rocket from the '80s.

I asked Mark the question about conventional nozzle use for SSTO. He stated that the problems associated with over-expansion were solved by UK research back in the 1950's.

He also stated that people seem to be making a big deal about the runway (10km length, concrete), whereas the sub-contractors who would be tasked have no issues with this.

The UK would be an unlikely location for such a runway - Kourou being the natural first choice - but it remains possible for polar-orbit payloads only.

As ukrocketman has stated, the REL team are all extremely busy right now, but rest-assured that Mark Hempsell still finds time to keep-up with this forum.

Offline 93143

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1665 on: 11/10/2013 09:09 PM »
He also stated that people seem to be making a big deal about the runway (10km length, concrete), whereas the sub-contractors who would be tasked have no issues with this.

I thought the runway was on the order of half that length.  Has it changed?

Good to hear they're pushing forward with the advanced nozzles...

That's an awful lot of nitrogen...  makes sense, though...
« Last Edit: 11/10/2013 09:16 PM by 93143 »

Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1666 on: 11/10/2013 09:24 PM »
I thought the runway was on the order of half that length.  Has it changed?

I don't believe the actual length was mentioned today; I may have picked that up (incorrectly?)elsewhere...

Offline Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1667 on: 11/10/2013 10:27 PM »
@SICA design (or anyone at REL ???)

So is the valkyrie being built to test possible expansion/deflection nozzles for SABRE? When do they plan to have the first flight test?

Why are REL looking at suborbital commercial aspects with VDSR? Is there much of a market for small suborbital payloads, and if there is why are REL getting involved? And anyway, surely the VDSR won't be flying for a while. At least not until after valkyrie tests are completed, or at least well under way.

BTW, thanks for the updates.
« Last Edit: 11/10/2013 10:31 PM by Citizen Wolf »
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Offline Turbomotive

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1668 on: 11/11/2013 05:42 AM »
Fantastic to get the latest news from REL :)
I suppose this will decide once and for all whether Skylon uses E/D nozzles or not.
Good luck with VDSR, seems extra workload on the REL team, but does VDSR have market prospects? Feels like a penny chew compared to a box of chocolates.

Many thanks to Rochelle (UK Space Environments Conference Organiser) for her kindness in allowing me to join as a (very) late delegate.

I can now reveal what Valkyrie/VDSR is all about (and, unlike ukrocketman, without fear for my legs - thanks Mark!).

Firstly Valkyrie:

This will be a small rocket, designed as an instrumented flying test-bed for plug-nozzle (e.g. STRICT, STERN) research and development.

It is designed to follow the velocity/altitude profile of Skylon (within 10%) and use an unusual tri-propellent mixture of nitrous oxide, ammonia and... liquid nitrogen!

The LN2 acts as a coolant and, crucially, allows the exhaust products to match those of SABRE in air-breathing mode.

Secondly VDSR:

This is a working-title for Valkyrie-Derived Sounding Rocket, an opportunity to capitalise on the design effort in Valkyrie, by producing a commercial sub-orbital rocket capable of lifting a small (10-20kg) payload to an altitude of 120-160km.

This will use a more-conventional fuel mixture of LOX/kerosene, keeping the same:

- pressure system
- tank diameter
- launch system
- solid rocket boost stage

This would have similar capabilities to the UK Petrel sounding rocket from the '80s.

I asked Mark the question about conventional nozzle use for SSTO. He stated that the problems associated with over-expansion were solved by UK research back in the 1950's.

He also stated that people seem to be making a big deal about the runway (10km length, concrete), whereas the sub-contractors who would be tasked have no issues with this.

The UK would be an unlikely location for such a runway - Kourou being the natural first choice - but it remains possible for polar-orbit payloads only.

As ukrocketman has stated, the REL team are all extremely busy right now, but rest-assured that Mark Hempsell still finds time to keep-up with this forum.
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Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1669 on: 11/11/2013 05:44 AM »
@SICA design (or anyone at REL ???)

So is the valkyrie being built to test possible expansion/deflection nozzles for SABRE?

Yes, exactly that.

Quote
When do they plan to have the first flight test?

Sorry - I do not know.

Quote
Why are REL looking at suborbital commercial aspects with VDSR? Is there much of a market for small suborbital payloads, and if there is why are REL getting involved? And anyway, surely the VDSR won't be flying for a while. At least not until after valkyrie tests are completed, or at least well under way.

The UK is serious about having a spaceport, principally to capture the emerging sub-orbital tourism market. Alongside this is anticipated an increase in sub-orbital scientific/industrial/other payloads. VDSR is being announced to test the market for such a launcher.

If there is money to be made, why would a UK rocket company not be interested (particularly since the cost of development is mostly absorbed into that for SABRE)?

Quote
BTW, thanks for the updates.

You're welcome!

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1670 on: 11/11/2013 07:42 AM »
Many thanks to Rochelle (UK Space Environments Conference Organiser) for her kindness in allowing me to join as a (very) late delegate.

I can now reveal what Valkyrie/VDSR is all about (and, unlike ukrocketman, without fear for my legs - thanks Mark!).

Firstly Valkyrie:

This will be a small rocket, designed as an instrumented flying test-bed for plug-nozzle (e.g. STRICT, STERN) research and development.

It is designed to follow the velocity/altitude profile of Skylon (within 10%) and use an unusual tri-propellent mixture of nitrous oxide, ammonia and... liquid nitrogen!

The LN2 acts as a coolant and, crucially, allows the exhaust products to match those of SABRE in air-breathing mode.
Well I did not see that one coming.   :)
Quote
Secondly VDSR:

This is a working-title for Valkyrie-Derived Sounding Rocket, an opportunity to capitalise on the design effort in Valkyrie, by producing a commercial sub-orbital rocket capable of lifting a small (10-20kg) payload to an altitude of 120-160km.

This will use a more-conventional fuel mixture of LOX/kerosene, keeping the same:

- pressure system
- tank diameter
- launch system
- solid rocket boost stage

This would have similar capabilities to the UK Petrel sounding rocket from the '80s.

I asked Mark the question about conventional nozzle use for SSTO. He stated that the problems associated with over-expansion were solved by UK research back in the 1950's.

He also stated that people seem to be making a big deal about the runway (10km length, concrete), whereas the sub-contractors who would be tasked have no issues with this.
We've had this one before. IIRC it's 15000 foot runway. Trouble is people usually quote runway lengths in feet
Quote

The UK would be an unlikely location for such a runway - Kourou being the natural first choice - but it remains possible for polar-orbit payloads only.
While it's possible an operator (probably the government) would base its operation in the UK, taking the reduction in payload I'd guess REL would prefer to do development  in the UK. If the runway allowed takeoff to orbit a lot of the development programme below full payload weight could be conducted from the UK.

That of course assumes takeoff noise is not an issue, otherwise I guess you'd be looking at build in the UK with ferry to Kourou for flight testing.

[edit. I will note it's been a long time since anyone fielded a liquid propellant sounding rocket. That said the size of the vehicle suggests the fueling package would be portable. Once a new nose payload is developed it's taken to the launch site, mated to the rocket, fueled and launched. ]
« Last Edit: 11/11/2013 07:47 AM by john smith 19 »
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1671 on: 11/11/2013 07:49 AM »
You are, as usual, correct :-)  It isn't an anacronym, it isn't a rehash of the XB70 (I wish it was), and it isn't "Vehicle for Demonstration of Skylon Readiness".
And now we know what it is.  :)

BTW were you able to find out if Westcott can accommodate a full size SABRE test?
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline Citizen Wolf

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1672 on: 11/11/2013 10:58 AM »
**The UK is serious about having a spaceport, principally to capture the emerging sub-orbital tourism market**

Compared to a working skylon, with full orbital capacity (once a passenger compartment is flight rated), who the heck would want to go sub-orbital?. Iíve never seen the attraction of sub-orbital flights myself. It seems like a big distraction and using up time and effort which could be better employed elsewhere. But, anyhow, Iím not privy to the strategic decisions that must be going on at the moment. I hope the correct ones are being made.

** If there is money to be made, why would a UK rocket company not be interested**

Yes, if thereís money to be made, then sure I guess itís worth considering. I wasnít aware of a market for suborbital payloads. The thing that surprises me is again is just whether itís a distraction from the main prize. Anyhow, Iím just a Joe Blow and Iíve never made a rocket and I havenít done the figures and costings so I donít know ;)

Thanks again.
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Offline francesco nicoli

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1673 on: 11/11/2013 05:11 PM »
Guys, I just have a question for those of you with engineering competences.

1) provided that (despite critics) there's a market for Mach 5 military planes, do you think SABRE might be adapted for that scope?

2) provided that there's a market for space tourism, do you think that SABRE engine can be adapted to create a 4-seat "miniskylon" that could be affordable for the super-rich? As far as I know, material costs of 1 skylon (15.000 payload) is 1 billion $. Could it be adapted for a 3000kg payload for turistic reasons? at what price?

thanks!

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1674 on: 11/11/2013 09:57 PM »
Guys, I just have a question for those of you with engineering competences.
1) provided that (despite critics) there's a market for Mach 5 military planes, do you think SABRE might be adapted for that scope?
No. LAPCAT was REL's study for a M5 aircraft and its associated M5 engine. They were quite adamant that launch is much easier than cruise.
Quote
2) provided that there's a market for space tourism, do you think that SABRE engine can be adapted to create a 4-seat "miniskylon" that could be affordable for the super-rich? As far as I know, material costs of 1 skylon (15.000 payload) is 1 billion $. Could it be adapted for a 3000kg payload for turistic reasons? at what price?
That price includes a lot of other stuff. But logically speaking you're looking at a $200m vehicle. The trouble is scaling  down the engines. Smaller LH2 pump --> higher pump speed. The figure Hempsell gave was something like a 300 kRPM impeller with a $200m development price.

Possible, maybe, but unlikely to be affordable.  :(
**The UK is serious about having a spaceport, principally to capture the emerging sub-orbital tourism market**

Compared to a working skylon, with full orbital capacity (once a passenger compartment is flight rated), who the heck would want to go sub-orbital?. Iíve never seen the attraction of sub-orbital flights myself. It seems like a big distraction and using up time and effort which could be better employed elsewhere. But, anyhow, Iím not privy to the strategic decisions that must be going on at the moment. I hope the correct ones are being made.
The initial goal of the programme is to flight test the attitude compensating nozzle. This will be the first flight test of an expansion/deflection nozzle (and hence of its design tools) in over 60 years (there have AFAIK been 2 plug nozzle flight tests in the US, and that's it for the altitude compensation flight test database).  :(

Quote
Yes, if thereís money to be made, then sure I guess itís worth considering. I wasnít aware of a market for suborbital payloads. The thing that surprises me is again is just whether itís a distraction from the main prize. Anyhow, Iím just a Joe Blow and Iíve never made a rocket and I havenít done the figures and costings so I donít know ;)
Historically a number of aerospace, astrophysics, mechanical and electronic engineering design courses have had an element of instrument design. Both balloon and sounding rocket programmes have been used to test these. Note that while the rocket has been been expendable (and typically a multi stage solid fuel) the payload nose has been recoverable (either by parachute or "crumple zone" nose or both) and allowed designed to be refined in a way that (historically) has not been possible with the secondary payload option on  an ELV, because once it's gone, it's gone.

It's one of those ideas that sounds a bit pointless but is actually quite handy.
« Last Edit: 11/11/2013 10:40 PM by john smith 19 »
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline Vultur

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1675 on: 11/12/2013 06:03 AM »
Is Valkyrie currently being built? still in the design stage? or what?

Offline Turbomotive

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1676 on: 11/12/2013 07:25 AM »
Is Valkyrie currently being built? still in the design stage? or what?

Maybe the better question is, is Valkyrie part of the SABRE demonstrator project?

If not, is VDSR conceived as a means to pay for the Valkyrie programme?

Bonus question from me: What's the theoretical advantage of E/D nozzle on SKYLON over bell nozzle? In terms of improved performance numbers.

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Offline flymetothemoon

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1677 on: 11/12/2013 08:15 AM »
1) provided that (despite critics) there's a market for Mach 5 military planes, do you think SABRE might be adapted for that scope?

Scaling the engine down has always been said to be an issue. Other than that, SABRE is, as John said, as far as I know, only really designed to sustain MACH 5 in air-breathing mode briefly, prior to transition to rocket mode - so unless you are leaving the atmosphere you'd be needing a Scimitar engine (Lapcat A2 - only a concept) rather than a SABRE.

2) provided that there's a market for space tourism, do you think that SABRE engine can be adapted to create a 4-seat "miniskylon" that could be affordable for the super-rich? As far as I know, material costs of 1 skylon (15.000 payload) is 1 billion $. Could it be adapted for a 3000kg payload for turistic reasons? at what price?

I don't see the need for scaling down. As long as there were no other requirements for the module, it looks to me like a D1 Skylon Passenger module could fit 30 people. Add lots of safety and extended emergency life support features for Joe Public and to offer a decent bit of leg room for the price you're going to pay and you're probably back down to 15-20 passengers again.
« Last Edit: 11/12/2013 08:17 AM by flymetothemoon »

Offline flymetothemoon

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1678 on: 11/12/2013 08:28 AM »
I don't see the need for scaling down. As long as there were no other requirements for the module, it looks to me like a D1 Skylon Passenger module could fit 30 people. Add lots of safety and extended emergency life support features for Joe Public and to offer a decent bit of leg room for the price you're going to pay and you're probably back down to 15-20 passengers again.

Let's say a Skylon launch costs $5,000,000. That works out to $250,000 per passenger based on 20 passengers. That's Virgin Galactic prices.

That's the paradigm shift with Skylon. Affordability and flexibility (and much increased reliability and safety). I don't understand why these points need to be laboured, but it does seem to need it, given some of the responses you see on here sometimes (that comment was definitely not aimed at you Francesco!).
« Last Edit: 11/12/2013 08:32 AM by flymetothemoon »

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (2)
« Reply #1679 on: 11/12/2013 08:43 AM »
I asked Mark the question about conventional nozzle use for SSTO. He stated that the problems associated with over-expansion were solved by UK research back in the 1950's.
That is a fascinating statement.  :o  Flow separation, and the asymmetrical loads it induces have been recurring problems in engine design for decades.

The usual answer I've seen is to increase chamber pressure or lower the expansion ratio. I'll note the SSME at 77: had issues and that was despite a Pch about 2x that of SABRE (in rocket mode).

My suspicion is that someone had been doing a bit of "archeological engineering"  :) in the archives and found "something," or talked to one of the original 1950's team ???

The big shift in the West was the shift to the "Contour," bell or Rao nozzle but I got the impression the Soviet Union went in a slightly different direction using the "method of moments," although I'm not sure how different the results actually were.

Likewise Rao described an "approximation" method of constructing a nozzle contour using IIRC conic sections. I'm wondering if a lot of the problems came when US engine mfgs used the short cut method to design the contour, rather than the "calculated" contour (given the cost and trouble of computer time). I've also wondered how big a part surface finish plays in the process.

The J-2S team were dealing with this because they wanted to do J2-S acceptance testing with the full nozzle at sea level pressure (IE no rare altitude chamber test stand). They were making progress when the programme got cancelled, but I can't recall details.

Maybe the better question is, is Valkyrie part of the SABRE demonstrator project?
I'd say it is. The STRICT/STERN E/D engines were uncooled, allowing burns of a few seconds. With modern data collection systems that's still plenty of time to collect relevant data but there has been no flight tests of an E/D nozzle ever. What's needed is a test of the nozzle through the whole pressure/speed range, if they want a serious go at putting it on the 1st generation Skylon.

It's not just the outside pressure that's a concern. That can be handled in an altitude chamber. It's a)Sweeping that atmospheric pressure and b)The outside jetstream flow. This was definitely a concern for plug nozzles, especially around transonic velocity. It should be less so for E/D nozles, and (I'm guessing) the models say it's not, but that's not actual proof. Generating a M5+ air flow with the right chemical composition and density without launching a test vehicle of some kind is tough.

Quote
If not, is VDSR conceived as a means to pay for the Valkyrie programme?
Probably not. REL need the data if they want their first Skylon to fly with E/D nozzles, which the timing suggests they do. I think they have partners for whom a viable VDSR is a core requirement, and I expect REL will do a solid job, but I doubt its a show stopper if VDSR does not go ahead.
Quote
Bonus question from me: What's the theoretical advantage of E/D nozzle on SKYLON over bell nozzle? In terms of improved performance numbers.
Look at Sutton. IIRC altitude losses caused by the difference between the optimum efficiency (design) altitude and all other altitudes seem to be the biggest loss in nozzle design. Something like 15%. So making an engines SL Isp more like it's vac Isp is a big win, giving a smaller tank size to deliver the same delta v. My notes say a <= 15% thrust loss between operating altitude and design altitude. Given most  engines are designed to operate at peak efficiency (Highest Isp) at high altitude that suggests you need a 15% smaller engine to do the job, although (in principal) you need to throttle down or turn engines off at high altitude because as you burn off propellant you hit the vehicles g limit.

That's not a problem I'd be bothered about

I'd say an empty VDSR could almost be carried by 1 man.  :)
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

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