Author Topic: Orbital ATK awarded DARPA Advanced Full Range Engine contract  (Read 20438 times)

Offline RanulfC

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It remains astonishing how fixated US aeroenging designers remain with supersonic combustion. It's even more astonishing how the USG continues to fund them.

Maybe because they know more than you. 

Well Jim so do fusion engineers and after almost 50 years of trying it's about time they get it out of the lab... Unfortunately as we know things are different outside the lab and it would seem what they 'know' still remains "it works great in theory..." and that if they keep promising it 'soon' they will continue to get money to keep trying.

Now none of this is especially "bad" as we eventually get advances out of this research, it's inevitable. The BAD thing is very often, (especially in the realm of supersonic combustion research) is that more near-term, often vastly more viable technology gets ignored or overlooked due to the aforementioned "fixation" (and that's what it is) on a single aspect of research and development.

Do we "need" SCramjets? No, that's rather obvious as there are other method of reaching and cruising at the speeds of interest. In fact researchers actually admit that the speed range of interest is LOW for supersonic combustion, but it is the 'default' technology.  Truth is hypersonic flight has never been hampered by PROPULSION it has ALWAYS been dependent on materials technology for the airframe. Hypersonic 'cruise' flight is VERY tough on the airframe but propulsion to get a vehicle to cruise at hypersonic speeds has been around for over 40 years.

The main issue with hypersonic flight still remains justification for the trouble and expense to build and operate a hypersonic airframe not the need for SCramjet propulsion.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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Orbital ATK awarded DARPA Advanced Full Range Engine contract
« Reply #21 on: 10/19/2017 08:41 am »

It remains astonishing how fixated US aeroenging designers remain with supersonic combustion. It's even more astonishing how the USG continues to fund them.

Maybe because they know more than you. 

Well Jim so do fusion engineers and after almost 50 years of trying it's about time they get it out of the lab... Unfortunately as we know things are different outside the lab and it would seem what they 'know' still remains "it works great in theory..." and that if they keep promising it 'soon' they will continue to get money to keep trying.

Now none of this is especially "bad" as we eventually get advances out of this research, it's inevitable. The BAD thing is very often, (especially in the realm of supersonic combustion research) is that more near-term, often vastly more viable technology gets ignored or overlooked due to the aforementioned "fixation" (and that's what it is) on a single aspect of research and development.

Do we "need" SCramjets? No, that's rather obvious as there are other method of reaching and cruising at the speeds of interest. In fact researchers actually admit that the speed range of interest is LOW for supersonic combustion, but it is the 'default' technology.  Truth is hypersonic flight has never been hampered by PROPULSION it has ALWAYS been dependent on materials technology for the airframe. Hypersonic 'cruise' flight is VERY tough on the airframe but propulsion to get a vehicle to cruise at hypersonic speeds has been around for over 40 years.

The main issue with hypersonic flight still remains justification for the trouble and expense to build and operate a hypersonic airframe not the need for SCramjet propulsion.

Randy

When LM are reportedly already flying a sub scale model of a hypersonic vehicle so this matter has rather moved on. Itís been clear the USAF wants such vehicles and they have an administration with both the former and current presidents who will give them the money to achieve these vehicles. The materials needed to build such vehicles appear to be in process. No doubt such craft will be very expensive to build but they are seen as a key component of global strike so I am sure those costs will be met.
« Last Edit: 10/19/2017 08:44 am by Star One »

Offline Arch Admiral

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The cross-section of the proposed engine is almost identical to the J67+RJ55 powerplant in the old Republic F-103. They studied that plane from 1951 to 1957, but couldn't make it work. There is a good account in Dennis R. Jenkins' book on the XB-70. Everything old is new again.

The basic problem with these combined engines is that the area and geometry of the intake and exhaust have to vary a lot to accommodate different speeds and Mach numbers. You need complex variable intakes with powerful actuators at a place suffering maximum airflow heating. Even plain turbojet planes like MiG-23/MiG-27 and B-1A/B-1B switched to fixed inlets in the 1970s at a considerable loss of speed in order to reduce the maintenance burden. The Chinese have recently made the same switch in J-17. When you add supersonic combustion the problems multiply.

Offline Star One

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The cross-section of the proposed engine is almost identical to the J67+RJ55 powerplant in the old Republic F-103. They studied that plane from 1951 to 1957, but couldn't make it work. There is a good account in Dennis R. Jenkins' book on the XB-70. Everything old is new again.

The basic problem with these combined engines is that the area and geometry of the intake and exhaust have to vary a lot to accommodate different speeds and Mach numbers. You need complex variable intakes with powerful actuators at a place suffering maximum airflow heating. Even plain turbojet planes like MiG-23/MiG-27 and B-1A/B-1B switched to fixed inlets in the 1970s at a considerable loss of speed in order to reduce the maintenance burden. The Chinese have recently made the same switch in J-17. When you add supersonic combustion the problems multiply.

I imagine thatís why LM & AJ took 4 years ground testing one.

Offline Asteroza

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That's part of the reason why the SR-71 with it's conical inlet worked so well: it is a simple forward/backward translation on a an internal pole/actuator.


Offline RanulfC

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When LM are reportedly already flying a sub scale model of a hypersonic vehicle so this matter has rather moved on. Itís been clear the USAF wants such vehicles and they have an administration with both the former and current presidents who will give them the money to achieve these vehicles. The materials needed to build such vehicles appear to be in process. No doubt such craft will be very expensive to build but they are seen as a key component of global strike so I am sure those costs will be met.

1) LM flew a subscale model of a fly-back rocket booster, (two years after a university student project did the same thing for 1/10th the budget) yet they didn't get a contract to build an actual vehicle. "Moved on" is relative in government projects, doubly so for defense projects. The key question would be did they fly a subscale vehicle at hypersonic speeds or are they just repeating the various prior projects and calling it "progress"?

2) Actually the USAF has "talked" about wanting a hypersonic vehicle bu they still don't have a definite mission or have defined operational usage of such a vehicle. "Global Strike" has often been suggested but the actual utility of such a vehicle has been questioned just as often and the Air Force has not been able to justify it as a requirement. Support of Presidental administrations and/or Congress does not constitute the ability to actually justify and fund a proposal. More often than not it actually just manages to funnel research funding to certain areas without resulting in working (operational) hardware. This is of course 'progress' but that's about it.

3)You misunderstand what I was getting at on materials vis-a-vis propulsion; We've had the propulsion since the 50s. we've actually had the materials as well. Combing the two to produce a viable hypersonic cruise vehicle should be fairly straightforward but has not been done mostly because programs gets sidetracked from that into cul-de-sacs like SCramjets. That obviously should not be enough to fully prevent the construction and use of a hypersonic vehicle and it is of course not the only factor. The MAIN factor is no one really "needs" a hypersonic cruise vehicle and that is as true today as it was in the 1960s. Therefore the funding and actually requirement to build and operate a hypersonic vehicle remains unavailable.

4) A hypersonic vehicle is only "key" to Global Strike when the Air Force needs it to be to get research funding. it tends to be 'lacking' when an operational requirement is asked for. Why? Simply you don't need a hypersonic cruise vehicle to perform Global Strike. "Nice to have" does not equate to an actual requirement and every time the Air Force attempts to build a requirment on those grounds it falls apart. The fact that SCramjes inevitably get tacked on to the "requirement" don't help. (The Air Force pointed this out to itself with the AFL study on the SABRE cycle. You can have a hypersonic cruise vehicle without SCramjets at which point the Air Force calls on LM to design a hypersonic cruise vehicle that uses SCramjets...)

We've had working SCramjets, (not that good but they at least 'worked' out of the lab) but not operational ones. We've had working materials and techniques to have a hypersonic cruise airframe, again just not an operational one. We've had working combined cycle engines, (up to an including a dual mode ram/SCramjet but not outside a lab) just not operational ones. We've had working hypersonic inlets and exhausts but not operational ones. Nothing in the current LM/Air Force offering would lead me to believe this iteration is any more likely to lead to an operational vehicle than previous projects. The inclusion of a requirement for an operational dual mode SCramjet in fact by the airframe designer in fact bias' it heavily in the direction of "only" another research project which will not end in actual hardware to me. The fact that the Air Force does not have a clear requirement or mission for such a vehicle pretty much seals the deal.

YMMV of course...

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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The cross-section of the proposed engine is almost identical to the J67+RJ55 powerplant in the old Republic F-103. They studied that plane from 1951 to 1957, but couldn't make it work. There is a good account in Dennis R. Jenkins' book on the XB-70. Everything old is new again.

The basic problem with these combined engines is that the area and geometry of the intake and exhaust have to vary a lot to accommodate different speeds and Mach numbers. You need complex variable intakes with powerful actuators at a place suffering maximum airflow heating. Even plain turbojet planes like MiG-23/MiG-27 and B-1A/B-1B switched to fixed inlets in the 1970s at a considerable loss of speed in order to reduce the maintenance burden. The Chinese have recently made the same switch in J-17. When you add supersonic combustion the problems multiply.

I imagine thatís why LM & AJ took 4 years ground testing one.

The point is that it was ground tested about 50 years ago, (and actually they DID get it to work) but it was heavy and inefficient and since aerodynamics and physics hasn't actually changed it is doubtful that the "new" models actually WORK better they just weigh less and are more expensive. The original issues still remain.

Arch Admiral: You're actually correct but missing the point. As a niche vehicle/engine it doesn't have to be either easy to maintain nor really 'efficient' in operation. The SR71 is the poster child for this :) IF it were built it just has to work as good as other options. The big problem is it can't because it's neither efficient or cost effective compared to "other" ways to accomplish the required mission. (Which in and of itself is to vague) The media keeps referring to these concepts at the SR72, (as do the Air Force and LM) specifically because they equate it to the missions that aircraft carried out.

Of course that ignores the historical and technical history of the SR71 which one can forgive the mostly non-specialist media but doesn't excuse the Air Force or LM. On the other hand they don't WANT anyone to examine the 'rational' very close and just accept that it will be as 'revolutionary' as the SR71 was in its day.

Unfortunately for that idea the 'mission' of the SR71 isn't there anymore and the current 'justifications' fall pretty flat when compared to other options available. You could accept the SR71 being a maintenance nightmare and hideously expensive as long as it had a justifiable and obvious mission. Once that was gone so was the SR71. When you don't even have a viable mission to start with....

That's part of the reason why the SR-71 with it's conical inlet worked so well: it is a simple forward/backward translation on a an internal pole/actuator.

Yep but also it's limitation as the conical intakes and the 'podded' engines reach a limit really quickly after about Mach-4. Above Mach-5 they actually become dangerous due to mach-shock interactions with the airframe. IIRC body mounted cones, (like those on the F-104) were tested but were far less efficient in a body compression type vehicle which is what is required for efficient hypersonic flight. (Moving the engines away from the body further is an option as in Skylon but that's also limiting. As they don't plan on going much over Mach-5 and the engines on the wingtips greatly simplifies the air flow issues that's understandable. Planning on cruising much over Mach-5 and you gain far to much integrating the engines and airframe)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Star One

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« Reply #27 on: 10/20/2017 06:35 am »
When LM are reportedly already flying a sub scale model of a hypersonic vehicle so this matter has rather moved on. Itís been clear the USAF wants such vehicles and they have an administration with both the former and current presidents who will give them the money to achieve these vehicles. The materials needed to build such vehicles appear to be in process. No doubt such craft will be very expensive to build but they are seen as a key component of global strike so I am sure those costs will be met.

1) LM flew a subscale model of a fly-back rocket booster, (two years after a university student project did the same thing for 1/10th the budget) yet they didn't get a contract to build an actual vehicle. "Moved on" is relative in government projects, doubly so for defense projects. The key question would be did they fly a subscale vehicle at hypersonic speeds or are they just repeating the various prior projects and calling it "progress"?

2) Actually the USAF has "talked" about wanting a hypersonic vehicle bu they still don't have a definite mission or have defined operational usage of such a vehicle. "Global Strike" has often been suggested but the actual utility of such a vehicle has been questioned just as often and the Air Force has not been able to justify it as a requirement. Support of Presidental administrations and/or Congress does not constitute the ability to actually justify and fund a proposal. More often than not it actually just manages to funnel research funding to certain areas without resulting in working (operational) hardware. This is of course 'progress' but that's about it.

3)You misunderstand what I was getting at on materials vis-a-vis propulsion; We've had the propulsion since the 50s. we've actually had the materials as well. Combing the two to produce a viable hypersonic cruise vehicle should be fairly straightforward but has not been done mostly because programs gets sidetracked from that into cul-de-sacs like SCramjets. That obviously should not be enough to fully prevent the construction and use of a hypersonic vehicle and it is of course not the only factor. The MAIN factor is no one really "needs" a hypersonic cruise vehicle and that is as true today as it was in the 1960s. Therefore the funding and actually requirement to build and operate a hypersonic vehicle remains unavailable.

4) A hypersonic vehicle is only "key" to Global Strike when the Air Force needs it to be to get research funding. it tends to be 'lacking' when an operational requirement is asked for. Why? Simply you don't need a hypersonic cruise vehicle to perform Global Strike. "Nice to have" does not equate to an actual requirement and every time the Air Force attempts to build a requirment on those grounds it falls apart. The fact that SCramjes inevitably get tacked on to the "requirement" don't help. (The Air Force pointed this out to itself with the AFL study on the SABRE cycle. You can have a hypersonic cruise vehicle without SCramjets at which point the Air Force calls on LM to design a hypersonic cruise vehicle that uses SCramjets...)

We've had working SCramjets, (not that good but they at least 'worked' out of the lab) but not operational ones. We've had working materials and techniques to have a hypersonic cruise airframe, again just not an operational one. We've had working combined cycle engines, (up to an including a dual mode ram/SCramjet but not outside a lab) just not operational ones. We've had working hypersonic inlets and exhausts but not operational ones. Nothing in the current LM/Air Force offering would lead me to believe this iteration is any more likely to lead to an operational vehicle than previous projects. The inclusion of a requirement for an operational dual mode SCramjet in fact by the airframe designer in fact bias' it heavily in the direction of "only" another research project which will not end in actual hardware to me. The fact that the Air Force does not have a clear requirement or mission for such a vehicle pretty much seals the deal.

YMMV of course...

Randy

I guess you havenít seen the recent news.

http://www.popularmechanics.com/military/aviation/news/a28420/hypersonic-sr-72-demonstrator-reportedly-spotted-at-skunk-works/

I already posted this in the general hypersonic thread.
« Last Edit: 10/20/2017 06:36 am by Star One »

Offline bad_astra

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Well Jim so do fusion engineers and after almost 50 years of trying it's about time they get it out of the lab...


What exactly does that mean.

And fusion researchers are reaching very good plasma containment times, recently. If you don't know the state of development in that field, than a luddite seeming statement isn't very helpful.
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Offline john smith 19

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That's part of the reason why the SR-71 with it's conical inlet worked so well: it is a simple forward/backward translation on a an internal pole/actuator.
Working out the "schedule" of Speed Vs spike position took 66 flights to calibrate. It has been estimated that to do that today would take 6 flights (with modern CFD)

However I thinks that's over the 3M range, not the more like 6M range  :(

But this thing is meant to be good up to about M6. I'm not sure how much of a database of airbreathing engines there is above about M3.5 (IE above the SR71 and XB70) to anchor CFD predictions.

BTW.
This is the review of the NASP/X-30 programme done after it had been running for 5 years in the early 90's, after the USAF had sunk North of $1Bn into it.

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940004890.pdf

It makes interesting reading for where they were and what they claimed to have accomplished. AIUI there reference engine design was to start with a Mach 3 LACE cycle and initially predicted "unstart" loads of 5x-10x to the loads of normal running, which is a pretty large range of uncertainty.

The review didn't think they were anywhere near a flight vehicle and recommend several $100m a year to continue for about 4 years to get a sub scale drone, which might get them to an actual full size flight vehicle.

That was the state of play in about 1993. I'll let others decide how far they think this subject has come. 
« Last Edit: 10/20/2017 08:09 pm by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Arch Admiral

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To expand on RanulfC's comments on the A-12/SR-71: This aircraft's designed mission (flying regular illegal peacetime recon missions over the USSR  a la U-2) went away before it even flew. The CORONA and GAMBIT spacecraft did the same job better, cheaper, and in accordance with international law. Their weak point was the time it took to return the film, which made them useless for tactical intelligence in wartime. It seems clear that the SR-71 fleet was retained to provide a faster recon capability during a major conventional war with the USSR. All the "operational" missions were really training exercises for WWIII.

Even this capability withered away as the Sovs provided the S-200 [SA-5] missile system and the MiG-25/31 interceptor to most of their puppet states. The Blackbird was dead meat to these systems (one was damaged by an old S-75 [SA-2] over Vietnam). They lasted as long as they did only because of their coolness factor.

Any "SR-72" would have to face late-model S-300s or S-400s or even tactical ABMs for which speed and altitude are no defense at all. There is no chance that this airplane will actually be funded.

Offline Star One

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Orbital ATK awarded DARPA Advanced Full Range Engine contract
« Reply #31 on: 10/26/2017 10:37 pm »
To expand on RanulfC's comments on the A-12/SR-71: This aircraft's designed mission (flying regular illegal peacetime recon missions over the USSR  a la U-2) went away before it even flew. The CORONA and GAMBIT spacecraft did the same job better, cheaper, and in accordance with international law. Their weak point was the time it took to return the film, which made them useless for tactical intelligence in wartime. It seems clear that the SR-71 fleet was retained to provide a faster recon capability during a major conventional war with the USSR. All the "operational" missions were really training exercises for WWIII.

Even this capability withered away as the Sovs provided the S-200 [SA-5] missile system and the MiG-25/31 interceptor to most of their puppet states. The Blackbird was dead meat to these systems (one was damaged by an old S-75 [SA-2] over Vietnam). They lasted as long as they did only because of their coolness factor.

Any "SR-72" would have to face late-model S-300s or S-400s or even tactical ABMs for which speed and altitude are no defense at all. There is no chance that this airplane will actually be funded.

Well being as it seemingly already has been your point is rendered utterly mute. If you really think the people developing this havenít thought of such matters regarding ground defences then thatís pretty insulting to them. Anyways I doubt the SR moniker is at all apt being it is actually being developed as part of global strike along with the B-21 & RQ-180. You do know aircraft actually deploy with lots of different types not singularly including multiple layers of electronic counter measures amongst other things?
« Last Edit: 10/26/2017 10:40 pm by Star One »

Offline john smith 19

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To expand on RanulfC's comments on the A-12/SR-71: This aircraft's designed mission (flying regular illegal peacetime recon missions over the USSR  a la U-2) went away before it even flew. The CORONA and GAMBIT spacecraft did the same job better, cheaper, and in accordance with international law. Their weak point was the time it took to return the film, which made them useless for tactical intelligence in wartime. It seems clear that the SR-71 fleet was retained to provide a faster recon capability during a major conventional war with the USSR. All the "operational" missions were really training exercises for WWIII.
Satellites other weak point is they fly predictable tracks, and can be avoided if you have their orbital parameters. The fact that low speed, high latitude drones continue to be used by the US suggests they are not the perfect solution.
Quote from: Arch Admiral
Any "SR-72" would have to face late-model S-300s or S-400s or even tactical ABMs for which speed and altitude are no defense at all. There is no chance that this airplane will actually be funded.
It does seem to be niche target. People who are sophisticated enough to threaten the current generation of subsonic high altitude drones but couldn't shoot this down?

This sounds like a fairly selective choice of enemies.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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To expand on RanulfC's comments on the A-12/SR-71: This aircraft's designed mission (flying regular illegal peacetime recon missions over the USSR  a la U-2) went away before it even flew. The CORONA and GAMBIT spacecraft did the same job better, cheaper, and in accordance with international law. Their weak point was the time it took to return the film, which made them useless for tactical intelligence in wartime. It seems clear that the SR-71 fleet was retained to provide a faster recon capability during a major conventional war with the USSR. All the "operational" missions were really training exercises for WWIII.
Satellites other weak point is they fly predictable tracks, and can be avoided if you have their orbital parameters. The fact that low speed, high latitude drones continue to be used by the US suggests they are not the perfect solution.
Quote from: Arch Admiral
Any "SR-72" would have to face late-model S-300s or S-400s or even tactical ABMs for which speed and altitude are no defense at all. There is no chance that this airplane will actually be funded.
It does seem to be niche target. People who are sophisticated enough to threaten the current generation of subsonic high altitude drones but couldn't shoot this down?

This sounds like a fairly selective choice of enemies.

I doubt those missiles would be able to successfully engage a vehicle such as the SR-72. The SR-71 after all successfully avoided increasingly sophisticated SAMs over its long life

Offline john smith 19

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I doubt those missiles would be able to successfully engage a vehicle such as the SR-72. The SR-71 after all successfully avoided increasingly sophisticated SAMs over its long life
I thought so too, but as others have pointed out it was fairly early banned from overflying the USSR, who would rank as the #1 in terms of altitude and speed of their air defense systems.

I suspect no client state was allowed their most advanced SAM's for fear of copies finding their way into the wrong hands.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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« Reply #35 on: 10/27/2017 03:56 pm »
I doubt those missiles would be able to successfully engage a vehicle such as the SR-72. The SR-71 after all successfully avoided increasingly sophisticated SAMs over its long life
I thought so too, but as others have pointed out it was fairly early banned from overflying the USSR, who would rank as the #1 in terms of altitude and speed of their air defense systems.

I suspect no client state was allowed their most advanced SAM's for fear of copies finding their way into the wrong hands.

The RQ-180 is rumoured to rely on very high levels of stealth and using the same trick as the U-2 thatís flying virtually on the edge of space and having sideways looking sensors. It can probably get closer in than the U-2 being a lot more stealthy. I assume though thatís not an option that will be open to the SR-72.
« Last Edit: 10/27/2017 03:57 pm by Star One »

Offline john smith 19

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The RQ-180 is rumoured to rely on very high levels of stealth and using the same trick as the U-2 thatís flying virtually on the edge of space and having sideways looking sensors. It can probably get closer in than the U-2 being a lot more stealthy. I assume though thatís not an option that will be open to the SR-72.
Yes. Operating at sub sonic speeds makes the material choices much wider, so it's probably got a high proportion of composite construction and careful shaping to reduce further.

For its time the SR71's RCS was very low (one of the key reasons it too 12 major revisions to design it), not just the lack of smooth surfaces and the in canted tails but also the sawtooth  structures inside the leading edges with Teflon wedges to act as broad band radio wave absorbers.

What it couldn't hide from was IR. A Mach 3 object maintaining a constant course and speed is not a natural phenomenon. Flying higher may offset the higher speed a bit but it's going to be a major target on any one with decent IR imaging that can track fast enough. The SoA in IR systems was a mechanically scanned mirror system with a single LN2 cooled "pixel" sensor.
Today the SoA is much more like a standard digital camera. I think the they try to make the arrays thermal mass as small as possible to allow cooling by solid state thermoelectric modules.

I'll note the SR71's turning circle was very large, A M5+ vehicle is likely to be even poorer in this regard.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¨cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Vahe231991

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Did the acquisition of Orbital ATK by Northrop Grumman in June 2018 affect the DARPA Advanced Full Range engine contract awarded to Orbital ATK in 2016, especially considering that the Valkyrie hypersonic aircraft concept envisaged in 2018 by Boeing (which co-partnered with Orbital ATK on the DARPA Advanced Full Range Engine study) has evolved in terms of design over the span of a few years?

Offline Jim

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Did the acquisition of Orbital ATK by Northrop Grumman in June 2018 affect the DARPA Advanced Full Range engine contract awarded to Orbital ATK in 2016, especially considering that the Valkyrie hypersonic aircraft concept envisaged in 2018 by Boeing (which co-partnered with Orbital ATK on the DARPA Advanced Full Range Engine study) has evolved in terms of design over the span of a few years?

why should it?  And this is a dead thread.

Offline RON_P

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Did the acquisition of Orbital ATK by Northrop Grumman in June 2018 affect the DARPA Advanced Full Range engine contract awarded to Orbital ATK in 2016, especially considering that the Valkyrie hypersonic aircraft concept envisaged in 2018 by Boeing (which co-partnered with Orbital ATK on the DARPA Advanced Full Range Engine study) has evolved in terms of design over the span of a few years?
From what i understand DARPA AFRE ended in 2021 and it's technologies moved to AFRL project Mayhem. Although more classified work on TBCC is still being done in DARPA ( with AFRL involvement of course ) as understood from this article
https://aviationweek.com/shownews/paris-air-show/ge-reveals-new-hypersonic-propulsion-effort
« Last Edit: 07/09/2023 06:35 pm by RON_P »

 

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