The Reaction Engines Skylon Master Thread (1)

[QuantumG]

I would disagree with QuantumG we are well past lab work stage particularly with the Pre-Cooler Heat exchanger; the modules on test are flight representative.  We are almost at TRL 5 and we fall short only because we have not yet put 1000C air through the intake

Precoolers not working or icing the engine?
The recent test programme has eliminated that possibility

Like!

Thanks for popping in.

Good luck!

Thanks for quoting it for me. If that isn't lab work, what would you call it? Prototype work? I call that lab work.

[simonbp]

Because you're not a scientist.

"Lab work" implies work that being done to understand a specific process, but which does not necessarily relate to any particular implementation. "Prototyping" or "experimental work" is work that is done to advance and prepare for a specific design.

So, the work on the precooler is more the latter, as it is flight-like hardware being tested for a specific application (exactly what is required for TRL 5). If they were doing more to just understand the fundamental thermodynamics of how air responds as it passes over the precooler, that would better be described as "lab work".

[QuantumG]

Because you're not a scientist.

Actually, I am, are you?

Anyway, thanks for defining the terms. I'll restate my original point:

So far this team has demonstrated they can do prototyping work but I've yet to see any evidence that they can actually put an aircraft into production.

If I'm wrong, please show me, I'm here to learn.

[Kharkov]

So far this team has demonstrated they can do prototyping work but I've yet to see any evidence that they can actually put an aircraft into production.

Fair enough, but, to use REL's own words, they don't plan to produce a Skylon vehicle themselves, just to hand over the design, construction blueprints & tooling plans to a manufacturing consortium later this decade.

Nacelle Test vehicles aside, nobody's expecting to see a Skylon, prototype or otherwise, fly for quite a few years yet.

[93143]

hand over the design, construction blueprints & tooling plans to a manufacturing consortium later this decade.

I'm not sure that's accurate; based on what's been said it seems to me that they plan to let the consortium handle the final detailed design of the vehicle.  Their own design (the D1, unless something crops up between here and there that triggers a redesign) is intended as a reference, not as something the airframer would just go and build.

[Kharkov]

hand over the design, construction blueprints & tooling plans to a manufacturing consortium later this decade.

I'm not sure that's accurate; based on what's been said it seems to me that they plan to let the consortium handle the final detailed design of the vehicle.  Their own design (the D1, unless something crops up between here and there that triggers a redesign) is intended as a reference, not as something the airframer would just go and build.

Hand over the design plus all documentation & notes?

[john smith 19]

Actually, I am, are you?

A scientist but not an engineer. In rocket engineering lab work implies either chemical work to elucidate basic information (EG testing a chemical combination for toxicity, Isp etc using *very* small amounts) or very sub scale work to check out mechanical principles EG devices a few tens of cm's across.

Anyway, thanks for defining the terms. I'll restate my original point:

So far this team has demonstrated they can do prototyping work but I've yet to see any evidence that they can actually put an aircraft into production.

In rocket engineering there's something called a test stand. It's the stage where you've either got major sub systems or complete rocket engines. It's normally outdoors as if something goes wrong there is substantial risk of a "rapid uncontrolled disassembly." These are fairly costly in time and money to set up and use.

Skepticism is completely understandable given REL's ambitions but a failure to recognise *progress* (and the stages it undergoes) is unhelpful. You seem to feel there is only "lab work" and "fully tested vehicle," which IRL aerospace projects is *very* far from the case.

You might like to look up the term "Work Breakdown Structure."

[Hempsell]

With regard to the discussion on the meaning of “lab work” I am with the concensous on what it means and we did that in the 1990s what we are doing now is rig testing.  However in all fairness to QuantumG officially TRL 4 is “Component and/or breadboard validation in laboratory environment” and we are not yet claiming TRL5.  However the testing we are doing is “Component and/or breadboard validation in relevant environment” which is TRL 5 testing, the only reason we are not claiming full TRL5 is because this rig cannot deliver intake air at 1000 degrees (although that has been done on the lab scale).  We will actually be doing that during the TRL6 testing which is what comes next. 

An example of why I do not like TRL levels much as they tend to be misinterpreted and misused

With regard to John smith’s comment on the NTV.  I am sorry to disappoint, but the NTV structure and systems are nothing like Skylon, it is just an aluminium tank monocoque with a pressure fed rocket engine, so there is no real knock on learning to be had - only a verification of the nacelle behaviour.

Re: Kharkov “Hand over the design plus all documentation & notes?” 
Perhaps I should make in clear it should read  “Hand over the design plus all documentation & notes in exchange for substancial financial reward commensurate with the value of the IPR contained therein.” just in case somebody out there is getting the impression we are a charity.

[Turbomotive]

would Mr Hempsell have anything to add to the debate on potential locations for a skylon Spaceport?

[john smith 19]

With regard to John smith’s comment on the NTV.  I am sorry to disappoint, but the NTV structure and systems are nothing like Skylon, it is just an aluminium tank monocoque with a pressure fed rocket engine, so there is no real knock on learning to be had - only a verification of the nacelle behaviour.

Pity. Given the Mach range (<= 5.5) I'd expected quite severe heating issues so going with the same materials as the full Skylon design *seemed* to make good sense, given the fringe benefits on staff training, production. leveraging the supply chain etc.

I'm curious how as to how you'll handle the heat issue. Will the pulse we so short that some sort of ablative approach, like SS2 will be adequate?

[Hempsell]

would Mr Hempsell have anything to add to the debate on potential locations for a skylon Spaceport?

I am afraid I have very little to add over the discussion on the thread.  Near the equator is good to reach all orbits and particularly Geostationary.  There is a bit of a performance gain into sun-synchronous from higher latitudes but I am not sure if the market for this orbit would be big enough to justify the investment.  The User Manual is designed to give a guide as to the performance an operator can expect from most places on the planet.

General requirements are a location where noise is not an issue, where a segregated airspace can be maintained to the east.  As I previously mentioned we have only analysed trajectories starting from sea level so I cannot answer in detail about the performance from high altitude sites.

We have done some studies of a few candidates e.g. Kourou and not found as show stopping issues.  We did have some brief discussions with Spaceport America and at superficial level it seem very suitable part from the loss of low inclinations.

[Hempsell]

With regard to John smith’s comment on the NTV.  I am sorry to disappoint, but the NTV structure and systems are nothing like Skylon, it is just an aluminium tank monocoque with a pressure fed rocket engine, so there is no real knock on learning to be had - only a verification of the nacelle behaviour.

Pity. Given the Mach range (<= 5.5) I'd expected quite severe heating issues so going with the same materials as the full Skylon design *seemed* to make good sense, given the fringe benefits on staff training, production. leveraging the supply chain etc.

I'm curious how as to how you'll handle the heat issue. Will the pulse we so short that some sort of ablative approach, like SS2 will be adequate?

In part the heating problem is solved by only going to Mach 4.5, it is also a very quick flight so we never go close to the steady state temperatures, there is also local heat protection and higher temperature materials in sensitive areas.

[john smith 19]

In part the heating problem is solved by only going to Mach 4.5, it is also a very quick flight so we never go close to the steady state temperatures, there is also local heat protection and higher temperature materials in sensitive areas.

A very *pragmatic* solution to the heat problem. I know this is one option but I hope it *will* fly.

[Citizen Wolf]

Are there are updates on the progress of upgrading the test facilities and a likely date for the delayed tests?

[Turbomotive]

would Mr Hempsell have anything to add to the debate on potential locations for a skylon Spaceport?

I am afraid I have very little to add over the discussion on the thread.  Near the equator is good to reach all orbits and particularly Geostationary.  There is a bit of a performance gain into sun-synchronous from higher latitudes but I am not sure if the market for this orbit would be big enough to justify the investment.  The User Manual is designed to give a guide as to the performance an operator can expect from most places on the planet.

General requirements are a location where noise is not an issue, where a segregated airspace can be maintained to the east.  As I previously mentioned we have only analysed trajectories starting from sea level so I cannot answer in detail about the performance from high altitude sites.

We have done some studies of a few candidates e.g. Kourou and not found as show stopping issues.  We did have some brief discussions with Spaceport America and at superficial level it seem very suitable part from the loss of low inclinations.

Thank you so much for all your time and effort for the community Lots of us are willing you to succeed. I believe Skylon will eventually kickstart a new space economy of manned bases everywhere in the solar system, threshold of Dan Dare / Thunderbirds / Space Cadet future. This is why I'm excited about Skylon.

[Hempsell]

Are there are updates on the progress of upgrading the test facilities and a likely date for the delayed tests?

Pre-cooler testing is ongoing and has been since the Farnborough air show, despite a helium shortage, with sucessful results. I cannot say more than that at the moment.

[Citizen Wolf]

Thanks for that Mark. Good to know. Hope all continues to go well.

[Jim]

Jim: we have designed Skylon to match all existing applications

How is that, when current comsats are nearly 7 MT and growing larger?

[Warren Platts]

would Mr Hempsell have anything to add to the debate on potential locations for a skylon Spaceport?

I am afraid I have very little to add over the discussion on the thread.  Near the equator is good to reach all orbits and particularly Geostationary.  There is a bit of a performance gain into sun-synchronous from higher latitudes but I am not sure if the market for this orbit would be big enough to justify the investment.  The User Manual is designed to give a guide as to the performance an operator can expect from most places on the planet.

General requirements are a location where noise is not an issue, where a segregated airspace can be maintained to the east.  As I previously mentioned we have only analysed trajectories starting from sea level so I cannot answer in detail about the performance from high altitude sites.

We have done some studies of a few candidates e.g. Kourou and not found as show stopping issues.  We did have some brief discussions with Spaceport America and at superficial level it seem very suitable part from the loss of low inclinations.

Hello Mark: thanks again for taking the time to post at this humble forum!

Actually, there was some discussion about building an airport at super-high altitudes. E.g., it might be feasible to build an airport straddling the equator as high as 5 km above sea level in Ecuador (or Bolivia).

Some people were saying it would likely be impossible to get airborne at that altitude. It seems to me its merely a problem of having a long enough runway; in which case, a marginal, yet possibly significant increase in performance (probably 3 to 5%) might be realized.

Of course Jim pointed out that launch costs for Skylon will be so inexpensive, it doesn't matter where in the world it launches from!

[Hempsell]

Jim: we have designed Skylon to match all existing applications

How is that, when current comsats are nearly 7 MT and growing larger?

When we compared Skylon's capability with the requirements for the New European Launch Service (NELS), which were primarily concerned with comms satellites and intended to be good to 2040, we found we could meet the mass targets with the Skylon Upper Stage, with the largest of the satellites using the Upper Stage in an expendable mode. In the longer term with something like Fluyt, satellites of 15 tonnes (on station) could be delivered.