Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 420006 times)

Offline alanr74

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1420 on: 03/29/2016 12:20 PM »
Seems like REL may have some competition in this area & LM hope to fly their demonstrator by 2018.


Quote
https://www.flightglobal.com/news/articles/lockheed-pushing-1-billion-mach-6-airbreather-423198/

Forgive me if I'm wrong but that article seems to be about ramjets in a craft the size of a f22. I don't think it is even close to like for like.

Offline knowles2

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1421 on: 03/29/2016 01:17 PM »
Scramjets have proven to be so successful, you know they only been trying to get them to work for the last 60 years or so, may this time they will succeed, I wouldn't place any money on it, especially as they fail to explain how they are going to get their aircraft up to Mach 6 to enable it to start operating the Scramjets.

http://epizodsspace.no-ip.org/bibl/inostr-yazyki/aerospace-america/2016/3/8-11.pdf

What this article neglect to say is that the whole engine can be tested and develop on the ground until all of the main problems, such as wear and tear of the combustion chambers are solved.

An well it not surprising the main criticism of Skylon come from people who are pursuing Scramjets, surely most funding for that dream would cease.
« Last Edit: 03/29/2016 01:59 PM by knowles2 »

Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1422 on: 03/29/2016 01:54 PM »
Ramjets have proven to be so successful, you know they only been trying to get them to work for the last 60 years or so, may this time they will succeed, I wouldn't place any money on it, especially as they fail to explain how they are going to get their aircraft up to Mach 6 to enable it to start operating the Ramjets.
Think you may be referring to SCRamjets (Supersonic Combustion Ramjet) - there's a difference...

Offline Star One

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The Reaction Engines Skylon Master Thread (5)
« Reply #1423 on: 03/29/2016 03:07 PM »
Seems like REL may have some competition in this area & LM hope to fly their demonstrator by 2018.


Quote
https://www.flightglobal.com/news/articles/lockheed-pushing-1-billion-mach-6-airbreather-423198/

Forgive me if I'm wrong but that article seems to be about ramjets in a craft the size of a f22. I don't think it is even close to like for like.

That's just the tech demonstrator that will be that size obviously not the final vehicle(s). The SR-72 alone if built will be 100 foot long plus, let alone any other vehicles that come from the research.

Scramjets have proven to be so successful, you know they only been trying to get them to work for the last 60 years or so, may this time they will succeed, I wouldn't place any money on it, especially as they fail to explain how they are going to get their aircraft up to Mach 6 to enable it to start operating the Scramjets.

http://epizodsspace.no-ip.org/bibl/inostr-yazyki/aerospace-america/2016/3/8-11.pdf

What this article neglect to say is that the whole engine can be tested and develop on the ground until all of the main problems, such as wear and tear of the combustion chambers are solved.

An well it not surprising the main criticism of Skylon come from people who are pursuing Scramjets, surely most funding for that dream would cease.

Do you honestly expect the full details of the research done by an organisation like Skunk Works to be in the public realm? There seems to be enough hints in the article and what is reported to suggest that elements of this technology have been developed out of the public gaze.
« Last Edit: 03/29/2016 03:32 PM by Star One »

Offline Archibald

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1424 on: 03/29/2016 04:58 PM »
Quote
    REL put the engines where they did because they are engine designers and not actually airframe designers.

Quote

Or maybe they put the engines where they did because it's actually the best place to put them if you aren't overly concerned about your design looking "futuristic" (ie: like the X-30).  These aren't really "hypersonic" engines, and may be better served by more traditional placement.

They put the engines on the wingtips because they are near the center of gravity.
Alan Bond learned a lesson the hard way with HOTOL: the RB-545 at the back made HOTOL completely unbalanced, and they lost a lot of time, money, most of the payload to orbit and political support trying to solve that issue.
« Last Edit: 03/29/2016 05:26 PM by Archibald »

Offline Archibald

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1425 on: 03/29/2016 05:36 PM »
I'll note that people who love the SCRamjet concept never talk about it's T/W or the very large system needed to get it up to operating speed.

It took me years to discover the current expected T/W for a SCRamjet is about 2:1. That's less than the combined J58/nacelle combination (and the combination was key to making the system work) for the SR71 in the mid 1950's.

6 decades of effort (starting roughly in 1960 at Johns Hopkins APL) has produced this.

Historically fixed geometry ramjets have been good for a an operating Mach range of about 3 IE M1-M4 M2-M5 at most disregarding the weight of the rocket (including propellant) or air breathing engines to get it there.

SABRE design (as it was planned to from day one) covers the whole range from 0 to M23. The downside is it's poor (but only  by rocket standards) T/W ratio (which is 50% better than state of the art turbofans).

SABRE buys a huge propellant tank (provided by the airflow through it) and that makes it's relatively poor IE T/W ratio 7x better than SCRamjet, performance, coupled with it's excellent air breathing Isp good enough to get the job done.


Excellent post. Nowadays scramjet for SSTOs is dead since the NASP debacle more than twenty years ago. Scramjet research has been redirected toward hypersonic missiles.
As for NASP, Tony Dupont oversold a naive DARPA staff a widly optimistic design - but Dupont is a politically astute con man, see the DP-2 story - scandal http://www.wired.com/2007/06/hunters_folly_6
« Last Edit: 03/29/2016 06:21 PM by Archibald »

Offline Star One

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1426 on: 03/29/2016 06:51 PM »
I'll note that people who love the SCRamjet concept never talk about it's T/W or the very large system needed to get it up to operating speed.

It took me years to discover the current expected T/W for a SCRamjet is about 2:1. That's less than the combined J58/nacelle combination (and the combination was key to making the system work) for the SR71 in the mid 1950's.

6 decades of effort (starting roughly in 1960 at Johns Hopkins APL) has produced this.

Historically fixed geometry ramjets have been good for a an operating Mach range of about 3 IE M1-M4 M2-M5 at most disregarding the weight of the rocket (including propellant) or air breathing engines to get it there.

SABRE design (as it was planned to from day one) covers the whole range from 0 to M23. The downside is it's poor (but only  by rocket standards) T/W ratio (which is 50% better than state of the art turbofans).

SABRE buys a huge propellant tank (provided by the airflow through it) and that makes it's relatively poor IE T/W ratio 7x better than SCRamjet, performance, coupled with it's excellent air breathing Isp good enough to get the job done.


Excellent post. Nowadays scramjet for SSTOs is dead since the NASP debacle more than twenty years ago. Scramjet research has been redirected toward hypersonic missiles.
As for NASP, Tony Dupont oversold a naive DARPA staff a widly optimistic design - but Dupont is a politically astute con man, see the DP-2 story - scandal http://www.wired.com/2007/06/hunters_folly_6

And what has any of that ancient history got to do with LM are doing now. That's the problem with people who oppose scramjet research they seem to live in the past and don't keep up with current developments.

Offline 93143

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1427 on: 03/29/2016 09:36 PM »
They put the engines on the wingtips because they are near the center of gravity.

We know.  The question is, could they be mounted closer to the fuselage, or even integrated into it?  Some think it might be better, others think it probably wouldn't.

Offline john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1428 on: 03/29/2016 10:33 PM »
And what has any of that ancient history got to do with LM are doing now. That's the problem with people who oppose scramjet research they seem to live in the past and don't keep up with current developments.
This is not a programme.

It's a PR campagn to try to get the US Congress to set one up for them.

On topic for this thread I'd love to find out what REL reckons such a vehicle costs when it's put through the standard cost models for aircraft.

I'll bet it's much higher than $1Bn and historically DARPA has funded much lower than this level for their projects.

Always keep in mind modern aircraft research  departments are viewed as profit, [not as cost centers for the company to maintain their technical edge. From their PoV it's only necessary that it get funded, not that it works.

People don't oppose SCramjets. They simply note it's a massively over promised (air breathing to orbit !) technology and (equally) massively under delivered, 4 decades just to make the thrust generated exceed the drag the engine creates in operation is not impressive.  :(

I'll also note this "double barrelled" over & under engine concept still gives you a large diameter (because you're dealing with stagnation temperature airflow, not highly densified near liquid)  high surface area duct made of very heavy materials which untill cruise is basically dead weight.
"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 john smith 19

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1429 on: 03/29/2016 10:35 PM »
Excellent post. Nowadays scramjet for SSTOs is dead since the NASP debacle more than twenty years ago. Scramjet research has been redirected toward hypersonic missiles.
As for NASP, Tony Dupont oversold a naive DARPA staff a widly optimistic design - but Dupont is a politically astute con man, see the DP-2 story - scandal http://www.wired.com/2007/06/hunters_folly_6
For legal reasons I would not call him a con man.
"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 Star One

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The Reaction Engines Skylon Master Thread (5)
« Reply #1430 on: 03/29/2016 11:03 PM »
And what has any of that ancient history got to do with LM are doing now. That's the problem with people who oppose scramjet research they seem to live in the past and don't keep up with current developments.
This is not a programme.

It's a PR campagn to try to get the US Congress to set one up for them.

On topic for this thread I'd love to find out what REL reckons such a vehicle costs when it's put through the standard cost models for aircraft.

I'll bet it's much higher than $1Bn and historically DARPA has funded much lower than this level for their projects.

Always keep in mind modern aircraft research  departments are viewed as profit, [not as cost centers for the company to maintain their technical edge. From their PoV it's only necessary that it get funded, not that it works.

People don't oppose SCramjets. They simply note it's a massively over promised (air breathing to orbit !) technology and (equally) massively under delivered, 4 decades just to make the thrust generated exceed the drag the engine creates in operation is not impressive.  :(

I'll also note this "double barrelled" over & under engine concept still gives you a large diameter (because you're dealing with stagnation temperature airflow, not highly densified near liquid)  high surface area duct made of very heavy materials which untill cruise is basically dead weight.

I'd put more money on LM in this competition at this time than REL if for no other reason that they are more likely to get their funding. Things like REL not receiving the money promised from government is going to do nothing but hamper their progress when it comes to financing.
« Last Edit: 03/29/2016 11:06 PM by Star One »

Offline Ravenger

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1431 on: 03/30/2016 09:48 AM »
So, what form is this single engine SABRE demonstrator likely to look like - something like the  Lockheed D21 drone perhaps?

That fits the description of looking more like a missile than an aircraft, and has the configuration you'd expect of a Mach 5 capable vehicle.

BAE's experience with the Taranis drone aircraft would be useful here, as number of its systems could be adapted for the SABRE demonstrator, especially the autonomous flight control systems.

Offline A_M_Swallow

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1432 on: 03/30/2016 10:06 AM »
I wonder how far this single engine vehicle can carry a spy camera at Mark 5?

Offline Hankelow8

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1433 on: 03/30/2016 10:43 AM »
And what has any of that ancient history got to do with LM are doing now. That's the problem with people who oppose scramjet research they seem to live in the past and don't keep up with current developments.
This is not a programme.

It's a PR campagn to try to get the US Congress to set one up for them.

On topic for this thread I'd love to find out what REL reckons such a vehicle costs when it's put through the standard cost models for aircraft.

I'll bet it's much higher than $1Bn and historically DARPA has funded much lower than this level for their projects.

Always keep in mind modern aircraft research  departments are viewed as profit, [not as cost centers for the company to maintain their technical edge. From their PoV it's only necessary that it get funded, not that it works.

People don't oppose SCramjets. They simply note it's a massively over promised (air breathing to orbit !) technology and (equally) massively under delivered, 4 decades just to make the thrust generated exceed the drag the engine creates in operation is not impressive.  :(

I'll also note this "double barrelled" over & under engine concept still gives you a large diameter (because you're dealing with stagnation temperature airflow, not highly densified near liquid)  high surface area duct made of very heavy materials which untill cruise is basically dead weight.

I'd put more money on LM in this competition at this time than REL if for no other reason that they are more likely to get their funding. Things like REL not receiving the money promised from government is going to do nothing but hamper their progress when it comes to financing.

Yet again a government promising money for a project that does not materialise.

I hope that at the very least the local MP is knocking on door of the treasury, asking "Where is our money".

Offline Star One

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1434 on: 03/30/2016 12:24 PM »
And what has any of that ancient history got to do with LM are doing now. That's the problem with people who oppose scramjet research they seem to live in the past and don't keep up with current developments.
This is not a programme.

It's a PR campagn to try to get the US Congress to set one up for them.

On topic for this thread I'd love to find out what REL reckons such a vehicle costs when it's put through the standard cost models for aircraft.

I'll bet it's much higher than $1Bn and historically DARPA has funded much lower than this level for their projects.

Always keep in mind modern aircraft research  departments are viewed as profit, [not as cost centers for the company to maintain their technical edge. From their PoV it's only necessary that it get funded, not that it works.

People don't oppose SCramjets. They simply note it's a massively over promised (air breathing to orbit !) technology and (equally) massively under delivered, 4 decades just to make the thrust generated exceed the drag the engine creates in operation is not impressive.  :(

I'll also note this "double barrelled" over & under engine concept still gives you a large diameter (because you're dealing with stagnation temperature airflow, not highly densified near liquid)  high surface area duct made of very heavy materials which untill cruise is basically dead weight.

I'd put more money on LM in this competition at this time than REL if for no other reason that they are more likely to get their funding. Things like REL not receiving the money promised from government is going to do nothing but hamper their progress when it comes to financing.

Yet again a government promising money for a project that does not materialise.

I hope that at the very least the local MP is knocking on door of the treasury, asking "Where is our money".

That must also send out the wrong signals to potential future investors I would have thought. What does it say when your own government doesn't follow through on pledges like that?

Offline Star One

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The Reaction Engines Skylon Master Thread (5)
« Reply #1435 on: 03/30/2016 05:20 PM »
Things like REL not receiving the money promised from government is going to do nothing but hamper their progress when it comes to financing.

That must also send out the wrong signals to potential future investors I would have thought. What does it say when your own government doesn't follow through on pledges like that?

I think you're taking that out of context, Mark Thomas's complaint  evidence to the committee was about  was about the pace of funding, not that it wasn't being followed through.


I hope that at the very least the local MP is knocking on door of the treasury, asking "Where is our money".
Would you mind writing to the Committee with the details of exactly what happened and the timings? It would be very helpful for the inquiry if we could understand exactly what has gone on and what bureaucratic hurdles you have had to overcome.

It was my understanding that none of this promised 60 million had been so far received?
« Last Edit: 03/30/2016 05:21 PM by Star One »

Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1436 on: 03/30/2016 08:15 PM »
It was my understanding that none of this promised 60 million had been so far received?
From the report, it would appear your understanding is correct:

Quote
Mark Wood:
"Let me give you a local example. Reaction Engines received a tremendous boost when it
was announced that we had achieved 60 million of Government investment back in 2013,
but it took two and a half years to get the grant agreement signed, and three years later we
still have not seen any of those funds flowing into the company. Potentially, it is a missed
opportunity in that it has given our competitors an extra three years to try to find ways to
beat our engine."
« Last Edit: 03/30/2016 08:30 PM by SICA Design »

Offline Paul451

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1437 on: 03/30/2016 08:19 PM »
So, what form is this single engine SABRE demonstrator likely to look like - something like the  Lockheed D21 drone perhaps?

When I first thought about it, that seemed like the most obvious solution. Except the D-21...



...burned JP-5 or similar fuel. A nice dense, hydrocarbon. Hence it only had relatively small toroidal tanks around its "waist".

SABRE burns liquid hydrogen, which is horribly low density. Even for a short flight, runway to Mach-5, the fuel volume will dominate the airframe.

In which case, I suspect they'll default to a simple engine-on-a-pylon...



...with the airframe being mostly tank.

Being a smaller airframe than the full Skylon, it shouldn't be as sensitive to CoG issues as the fuel is used up. Plus putting the GNS and a large science package in the nose will balance out some of the mass of the engine. That lets you move the engine further rearward, letting you keep the pylon shorter without either dirty airflow or thermal issues on the tail, simplifying the design by keeping the line of thrust closer to the airframe.

Additionally, the pylon configuration should drop naturally out of prior air testing. I would expect them to carry a SABRE on a conventional jet aircraft, first to test the heat-exchange in flight, then to do subsonic hot runs; before switching to the self-contained test vehicle for the supersonic runs.

Offline Hankelow8

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1438 on: 03/30/2016 08:35 PM »
Things like REL not receiving the money promised from government is going to do nothing but hamper their progress when it comes to financing.

That must also send out the wrong signals to potential future investors I would have thought. What does it say when your own government doesn't follow through on pledges like that?

I think you're taking that out of context, Mark Thomas's complaint  evidence to the committee was about  was about the pace of funding, not that it wasn't being followed through.


I hope that at the very least the local MP is knocking on door of the treasury, asking "Where is our money".
Would you mind writing to the Committee with the details of exactly what happened and the timings? It would be very helpful for the inquiry if we could understand exactly what has gone on and what bureaucratic hurdles you have had to overcome.

It was my understanding that none of this promised 60 million had been so far received?

I guess we would all agree the UK government should honour  their 60 million promise to RE.

How about  this forum creating a petition we could present to HM government.

I fully understand if the management of this forum do not wish to dip their toes into politics, but do we just say nothing and allow government to play politics with the aero space industry.

Offline SICA Design

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Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1439 on: 03/30/2016 08:37 PM »

This was the original REL concept for a Nacelle Test Vehicle:

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