People have been thinking about this since the dawn of the space age. See Spiral for example.... but large hypersonic aircraft are really expensive to develop. It's not at all clear this is a win over a conventional booster. I'm not clear what the payload capacity of the SR-72 is supposed to be, but if it's comparable to the SR-71 it would only be good for a tiny tiny. The D21 was something like 5 tons (also it was ramjet powered, not rocket). For comparison, the original Pegasus (not XL) was more like 18 tons.
The concept of the SR-72 from the information LM put out in AW posits an aircraft that looks slightly bigger than the SR-71. I was thinking along the lines of deploying the smaller end of satellites perhaps cubesats and a bit bigger. Would that be a workable concept, or would the launcher for such payloads still need to be too big for such a size of aircraft?
The thing is if LM have created a concept for a workable engine allowing hypersonic performance is there anything in theory stopping them putting these on a larger airframe.
Take Rockwell B1 Lancer - an active supersonic heavy bomber:
Quote from: dror on 06/28/2014 12:49 pmTake Rockwell B1 Lancer - an active supersonic heavy bomber:Wrong.The B1a was supersonic. The B1B has fixed inlets and is subsonic. It's certainly not hypersonic.
Quote from: Star One on 06/28/2014 10:20 amThe concept of the SR-72 from the information LM put out in AW posits an aircraft that looks slightly bigger than the SR-71. I was thinking along the lines of deploying the smaller end of satellites perhaps cubesats and a bit bigger. Would that be a workable concept, or would the launcher for such payloads still need to be too big for such a size of aircraft?Well the SR71 accomdated the D21 drone at about 5 tonnes. Given the usual ELV payload is 3% of GTOW that would about 150Kg to orbit. Provided someone has put up the shed load of cash to build the "SR72" (which is a powerpoint plane at this point) and this ELV add on.That kind of money buys an awful lot of Pegasus launches.QuoteThe thing is if LM have created a concept for a workable engine allowing hypersonic performance is there anything in theory stopping them putting these on a larger airframe.Let's go through the logic chain. if LM have a viable engine and if they get a sponsor (because you can bet they won't internally fund this) to build the aircraft and if they get a sponsor to build the LV then yes they probably could launch payloads to LEO.Now why would they want to? What's in it for them?My instinct is that when the first SCEPTRE engine starts ground tests in about 3 years they will still be talking about this.As they will in 7 years time, when the first Skylon starts flight testing.
I was wondering a while ago about the possibility of half scale SABRE engines for a test vehicle and it occurred to me that if you could could replace the B1 lancer's fuel tanks with cryogenic tankage and the jet engine pods with SABRE nacelles the B1 airframe is designed to handle mach 2+ and could possibly rock zoom from there to mach 8 for an air launch. It would make an interesting test aircraft both for engine development and for the logistics of cryogenically fueled aircraft management and handling. The B1 has about 215m3 of fuel volume, or about 16mt of Hydrogen IIRC.
Quote from: lkm on 06/28/2014 08:53 pmI was wondering a while ago about the possibility of half scale SABRE engines for a test vehicle and it occurred to me that if you could could replace the B1 lancer's fuel tanks with cryogenic tankage and the jet engine pods with SABRE nacelles the B1 airframe is designed to handle mach 2+ and could possibly rock zoom from there to mach 8 for an air launch. It would make an interesting test aircraft both for engine development and for the logistics of cryogenically fueled aircraft management and handling. The B1 has about 215m3 of fuel volume, or about 16mt of Hydrogen IIRC.A single B1 engine in full burner is 30 000lbf of thrust. A SABRE is 360 000 lbf of thrust.Firstly there no B1B has been released for test purposes. Secondly there is no real point in building a 1/12 scale SABRE to fit to such a vehicle. Thirdly a full air breathing cycle for a SABRE is to M5.5. A B1B will not survive sustained flight at that The best flight test vehicle for SABRE remains a Skylon.
Quote from: john smith 19 on 06/28/2014 10:02 pmYes well that depends on them finding someone willing to give them the not inconsiderable amount of money to build Skylon, something I am far from convinced is going to happen anytime soon.
Yes well that depends on them finding someone willing to give them the not inconsiderable amount of money to build Skylon, something I am far from convinced is going to happen anytime soon.
The concept of the SR-72 from the information LM put out in AW posits an aircraft that looks slightly bigger than the SR-71.
I was thinking along the lines of deploying the smaller end of satellites perhaps cubesats and a bit bigger. Would that be a workable concept, or would the launcher for such payloads still need to be too big for such a size of aircraft?
Quote from: john smith 19 on 06/28/2014 10:02 pmQuote from: lkm on 06/28/2014 08:53 pmI was wondering a while ago about the possibility of half scale SABRE engines for a test vehicle and it occurred to me that if you could could replace the B1 lancer's fuel tanks with cryogenic tankage and the jet engine pods with SABRE nacelles the B1 airframe is designed to handle mach 2+ and could possibly rock zoom from there to mach 8 for an air launch. It would make an interesting test aircraft both for engine development and for the logistics of cryogenically fueled aircraft management and handling. The B1 has about 215m3 of fuel volume, or about 16mt of Hydrogen IIRC.A single B1 engine in full burner is 30 000lbf of thrust. A SABRE is 360 000 lbf of thrust.Firstly there no B1B has been released for test purposes. Secondly there is no real point in building a 1/12 scale SABRE to fit to such a vehicle. Thirdly a full air breathing cycle for a SABRE is to M5.5. A B1B will not survive sustained flight at that The best flight test vehicle for SABRE remains a Skylon. Yes it would be tremedously over powered and this was really just a thought experiment regarding whether there were any suitable existing airframes you could stick a SABRE on but I was really rather thinking of it as something the USAF might do down the road to to explore the performance and needs of the engine type before committing to a cruise engine development program for some future bomber and not something REL would be doing. Also I wasn't suggesting airbreathing to M5.5, rather that you could go to the rocket mode before you hit the limit of the airframe somewhere around Mach 3.
I've read PSLV-CA launches go for something like $17 million, and can put ~1 ton into to LEO. That's a lot of cubesats, any very tiny fraction of what something like the SR-72 program would cost. Even if you assume the basic SR-72 program is paid for by someone else, just the cost of developing the launch system would buy you a pretty substantial number of conventional smallsat launches.
In operation, how long would Skylon spend between Mach 3 and 5.5 when it enters rocket mode?
I think this is a valid idea for the USAF supported by REL. I'm guessing but if the airframe could support close to M3 in sustained flight then maybe it could do a sprint to >M4 for a limited period. Hence my question above. All done unmanned of course.
Quote from: IslandPlaya on 06/28/2014 11:50 pmI think this is a valid idea for the USAF supported by REL. I'm guessing but if the airframe could support close to M3 in sustained flight then maybe it could do a sprint to >M4 for a limited period. Hence my question above. All done unmanned of course.I'm really struggling to understand how shoe horning one or more SABRE's onto a B1B airframe will have any relevance to the idea of a hypersonic launch assist stage. That's the title of this thread.IRL the USAF would need REL to design a sub scale SABRE for them, they can't do it themselves and neither can their regular contractors (because they don't know how).Hempsell on the Skylon threads stated LH2/LO2 engines scale down badly. He estimated they would spend Ł250m on a scaled down LH2 pump for the SCEPTRE ground test engine. At that point they decided to go for a little bit more funding and go with a full size ground test, instead of a sub scale. OTOH REL have studied an M5 aircraft and an engine to power it under LAPCAT.It's a very different beast because it's a very different mission.
Well, as I think you'll agree, there are no existing hypersonic aircraft, certainly no large ones capable of air launch. Also the cost of designing and building a new purpose built aircraft would be at least as much, if not more, than the cost of building Skylon. It's for this reason that most schemes for supersonic airlaunch involve sticking some rockets on an existing subsonic aircraft for a rocket zoom out of the atmosphere, bodging is cheaper. So if you want to do hypersonic air launch, as per the thread, a bodged B1 would be cheaper than a new aircraft. Should the USAF wish to do such a crazy thing, of course REL would be contracted for the engine, and paid handsomely for it, no doubt it would have to be the notional US subsidiary supplying the notional US Skylon airframer being contracted.
Quote from: lkm on 06/29/2014 10:56 amWell, as I think you'll agree, there are no existing hypersonic aircraft, certainly no large ones capable of air launch. Also the cost of designing and building a new purpose built aircraft would be at least as much, if not more, than the cost of building Skylon. It's for this reason that most schemes for supersonic airlaunch involve sticking some rockets on an existing subsonic aircraft for a rocket zoom out of the atmosphere, bodging is cheaper. So if you want to do hypersonic air launch, as per the thread, a bodged B1 would be cheaper than a new aircraft. Should the USAF wish to do such a crazy thing, of course REL would be contracted for the engine, and paid handsomely for it, no doubt it would have to be the notional US subsidiary supplying the notional US Skylon airframer being contracted. AFAIK the only one currently being talked about is the XS1 project from DARPA. That is looking to go to M10 with a 3000lb payload. If you can pack an ELV in 3000lb then that would pretty much fit the bill.The X15 did get to M6.15 in the mid 60's.The B1B is not rated beyond about M2.25 (which is what the a version got to). If you're air breathing anyway you'd go with the LAPCAT engine instead and only have to worry about LH2 storage, not both LH2 and LO2. The idea of airborne launch assist (both sub and supersonic) has been discussed at length on this site and on various news groups (primarily sci.space.tech) for the last 25 years.You might like to read some of that before commenting further.
As we are talking about the future here why not go the whole hog if you're going to want a big airframe surely the Long Range Strike Bomber whatever that turns out to be would be more appropriate than a B1-B.
Quote from: Star One on 06/30/2014 05:01 pmAs we are talking about the future here why not go the whole hog if you're going to want a big airframe surely the Long Range Strike Bomber whatever that turns out to be would be more appropriate than a B1-B.Probably not there seems to be less of a trend towards heavy aircraft being supersonic so its more likley the LRSB will be slower (and more stealthy) rather than faster. Right now it looks like the LRSB is the "last-hope" for the Blended-Wing-Body aircraft to see the light of day... Someday Randy
"Better" would be to not use "lifting" flight at all and remove all the wings-and-wheels and just go for a near vertical trajectory from a vertical launch using MIPCC and jet engines to reach staging at Mach-5 and 150,000ft or so where the hypersonic lifting body "ATP/BH" takes over on rocket power to orbit. First stage flies back to a vertical landing and is quickly checked out and ready to go within hours at most. See, easy
The USAF have hinted it will be supersonic.http://breakingdefense.com/2014/06/air-force-keeps-mum-on-new-bomber-rfp/
For reference, a B-1B-esqe system seemed to have been proposed.Using a civil variant of the TU-160 Blackjack bomber called the TU-160SK, there was an air launched LV called Burlak (later improved variant called Diana-Burlak after germany became involved). TU-160 had variable intakes so nominally can go faster than a B-1B in theory. The conversion suggests that the TU-160SK had a centerline external LV payload, with a carrier pylon closely hung and spanning all the former bomb bays. Burlak was predicted to be able to do 700 Kg to equatorial LEO, 1100 Kg for Diana-Burlak. http://www.aerospaceguide.net/burlak.html
Quote from: RanulfC on 06/30/2014 02:46 pm"Better" would be to not use "lifting" flight at all and remove all the wings-and-wheels and just go for a near vertical trajectory from a vertical launch using MIPCC and jet engines to reach staging at Mach-5 and 150,000ft or so where the hypersonic lifting body "ATP/BH" takes over on rocket power to orbit. First stage flies back to a vertical landing and is quickly checked out and ready to go within hours at most. See, easy TBF at M5 almost anything has some aerodynamic lift, the question is do you want to use it?
I think you've hit the nail on the head that "modding" an aircraft to get to M5 is going to be nightmareishly complex and building one from scratch eyewateringly expensive. The "launch assist platform" architecture still looks quite good for this, ideally with minimal changes to the engine nacelles if possible.AFAIk the only thing that comes close to this plan (in the US) is the DARPA Experimental Spaceplane 1 programme, but I'm not sure if there's been any action on it lately.
The big problem with airlaunch is the development cost. So a good launcher is capable of doing more than just space launch. Skylon will be used for supersonic/hypersonic travel as wel as launching stuff into LEO. The ALTO crossbow design was intended to be used as a conventional airplane, a mobile missile launcher, and what not. The sales pitch is more convenience for passengers and airline companies. Launching things into space is only a small part of what it does. (Great infographics in the L2 section, btw).
One thing that's a big problem with hypersonic flight is the huge heat build up on the airframe.
One thing that's a big problem with hypersonic flight is the huge heat build up on the airframe. I have a hunch that any advanced design in the future might be using metamaterials as the solution to this particular issue. The large heat build up & strain on the airframe has been one of the main limitations on sustained hypersonic flight (as touched on in the link below). As a launch platform I would think sustained hypersonic velocities would be best.http://phys.org/news/2012-04-darpa-hypersonic-glider-anomaly.html
Quote from: Star One on 07/01/2014 01:57 pmOne thing that's a big problem with hypersonic flight is the huge heat build up on the airframe. True.So why do it?
Can I just point out that I never suggested moding a B1 to do hypersonic airbreathing.
My thinking was airbreathing to mach 2+, whatever the limit of the airframe, and then rocket zoom out of the atmosphere to release the payload safely then glide back. The payload would be something like a Pegasus at 20mt for space launch or a hypersonic strike weapon, either way carried externally from the hardpoints as the bomb bays would be cryogenic fuel tanks.
Seems like some kind of supersonic turbo-rocket would be more effective. Maybe a using a high altitude launch of a solid fuel air augmented rocket launched from a mothership aircraft would be more practical than a "hypersonic" craft. I would expect at high enough altitude Mach 4 might be sufficient to get you small payloads into space.
Wasn't the Soviet Union supposed to be developing a hypersonic aircraft for satellite launch, or did I imagine that?
Quote from: Star One on 07/01/2014 06:09 pmWasn't the Soviet Union supposed to be developing a hypersonic aircraft for satellite launch, or did I imagine that?You're imagining things, really sit down and take a deep breath, close your eyes and let the nice men in the white coats fit you for your nice padded cell... The Spirel 50/50: http://www.aerospaceguide.net/spaceplanes/spiral.htmlhttp://www.spacebanter.com/showthread.php?t=54715Depending on which "version" you're looking at the carrier aircraft was either high-supersonic (Mach-4) or low hypersonic (Mach-6) at release of the second stage vehicle which would be outfitted with either the Mig105-11/13 space plane of a satellite.Randy
It's very frustrating trying to do any research into this particular subject and hypersonic aviation in general online as the whole topic seems infested with exaggerated claims and projects that either never existed or never got off the drawing board. That said there seems to be more interest and money being poured into this area than ever before and this combined, as this new article on Space Review says, maybe the time of the airborne launcher is here at last.http://www.thespacereview.com/article/2543/1
Acetylene is notorious as being very shock sensitive.
QuoteAcetylene is notorious as being very shock sensitive.I seem to remember my old metalwork teacher, Gripper Grundy, fair throwing around the acetylene cylinder when changing it in when we were cutting up some metal sheet...
Quote from: Star One on 07/01/2014 07:34 pmIt's very frustrating trying to do any research into this particular subject and hypersonic aviation in general online as the whole topic seems infested with exaggerated claims and projects that either never existed or never got off the drawing board. That said there seems to be more interest and money being poured into this area than ever before and this combined, as this new article on Space Review says, maybe the time of the airborne launcher is here at last.http://www.thespacereview.com/article/2543/1"a combination of nitrous oxide and acetelyene, mixed together in the same propellant tank and “slightly chilled” below room temperature, Clapp said. "That's kind of sporty. Acetylene is notorious as being very shock sensitive. I wonder if they will be using some kind of catalyst involved?Note the bigitem. No new aircraft, only ones that can be assigned without complex (IE recertifiable) changes.
Well if they are going to put that F-15E imagine how much larger the payload capacity could be on an evolved version if carried on a larger future airframe.
Quote from: IslandPlaya on 07/01/2014 09:42 pmQuoteAcetylene is notorious as being very shock sensitive.I seem to remember my old metalwork teacher, Gripper Grundy, fair throwing around the acetylene cylinder when changing it in when we were cutting up some metal sheet...That's fine.Acetylene cylinders are packed with a porous medium (usually agamassan these days) and half filled with an organic solvent in which the acetylene gas dissolves (and renders it non-explosive). The porous material absorbs gaseous acetylene that is not in solution to prevent it from forming larger unstable volumes. This technique is effective in making acetylene cylinders safe to handle.
AFAIK the one of the reasons the F15 is liked is because it has a very high (for an aircraft) T/W ratio and can do high AoA climbs. I'm not sure if it can do fully vertical (relying on engine thrust alone) but well above 45deg to the horizontal.
Quote from: Star One on 07/02/2014 06:37 amWell if they are going to put that F-15E imagine how much larger the payload capacity could be on an evolved version if carried on a larger future airframe.AFAIK the one of the reasons the F15 is liked is because it has a very high (for an aircraft) T/W ratio and can do high AoA climbs. I'm not sure if it can do fully vertical (relying on engine thrust alone) but well above 45deg to the horizontal.You'll note it's an old design and AFAIK nothing comes close in that area because they were not designed to do so.
As you yourself say it is an old design. The average age of the USAF fleet is something like 24 years old & the F15 is contributing to that high average. As the USAF have indicated they want stealth everywhere it wouldn't surprise me if we don't see it replaced sooner rather than later.
Quote from: Star One on 07/02/2014 10:24 amAs you yourself say it is an old design. The average age of the USAF fleet is something like 24 years old & the F15 is contributing to that high average. As the USAF have indicated they want stealth everywhere it wouldn't surprise me if we don't see it replaced sooner rather than later.Looking up the Wikipedia entry on thrust to weight ratio I see the T/W for the F15k is reckoned to be about 1.15 :1 while the newer design F22 is just a little better at 1.19:1 while none of the F35 variants listed is above 0.9:1High rate of climb is useful for "scrambles" but I get the feeling stealth is prized much more and that tends to cut performance, not least because at > M1 the whole aircraft makes a good IR target, regardless of what radar coating or shaping has been used.
It wouldn't surprise if that dichotomy will not be resolved with the advances in stealth technology especially to deal with IR signature. I say this as it's pointless to have stealth in some areas of the electromagnetic spectrum but not others
and that is why the holy grail seems to be broad spectrum stealth. I am hopeful that an airframe will arise that can take on this particular task from the F15.
DARPA have a lot more knowledge than us about what will arise in future and this launcher seems to be plug & play for a better use of words so it wouldn't surprise me if it was easily adaptable to future platforms.
It's very frustrating trying to do any research into this particular subject and hypersonic aviation in general online as the whole topic seems infested with exaggerated claims and projects that either never existed or never got off the drawing board.
That said there seems to be more interest and money being poured into this area than ever before and this combined, as this new article on Space Review says, maybe the time of the airborne launcher is here at last.http://www.thespacereview.com/article/2543/1
Quote from: Star One on 07/02/2014 01:29 pmIt wouldn't surprise if that dichotomy will not be resolved with the advances in stealth technology especially to deal with IR signature. I say this as it's pointless to have stealth in some areas of the electromagnetic spectrum but not others True.
Quoteand that is why the holy grail seems to be broad spectrum stealth. I am hopeful that an airframe will arise that can take on this particular task from the F15.That's more debatable. Again it won't be hypersonic either. IRL the nearest to a large M5 aircraft has been the XB70, designed to carry 50 tonnes of bombs to Moscow. That managed M3 in a cost effective stainless steel honeycomb ( but man what an RCS)
QuoteDARPA have a lot more knowledge than us about what will arise in future and this launcher seems to be plug & play for a better use of words so it wouldn't surprise me if it was easily adaptable to future platforms.True but so what? will the new aircraft have a bigger payload to allow a bigger payload to orbit? Will it have a higher top speed? In either case I'd have to say doubtful. "Makes a good ELV launcher" is IMHO not at the top of any USG aircraft contractor (although obviously it's at the top of Stratolaunches ).
Worse actually as the "active-lift" of capturing the supersonic shockwave under the wings by folding the wingtips increased the RCS ten-fold by themselves! (Which is why a small "Quail" ECM-decoy can look to a radar as big as the B-52s which carried it! http://en.wikipedia.org/wiki/ADM-20_Quail)
Seriously the F-22 IS the "replacement" for the F-15 as the F-35 is supposed to "replace" the F-16, and both 'replacement' airframes are not in many ways as "capable" as the aircraft they are replacing. The only current military "planned" hypersonic vehicles are drones or weapons. There is no need forseen for any manned hypersonic vehicles in the forseeable future
Actually I'd be surprised if the government isn't looking at the StratoLaunch aircraft as a possible "test-bed" for testing ideas on modular strategic mobility and support aircraft as pointed to in the CATS concept I mentioned above. In a lot of ways it makes sense to move in that direction for both civil and military "heavy" aviation needs.In general there is little interest in "supersonic" aircraft for civil and military use (the military really only "needs" speed to allow flexible engagement parameters, I.E. you can run when you don't want to fight or engage an enemy who's trying to run away, but the old "Interceptor" role is much less of a priority than manueverability is these days) outside of certain narrow and mostly un-economical uses. Hypersonics is only sees an "possible" should long-distance travel show a very high need for "shorter" travel times. This has actually not been the case since telecommunications allow almost as much flexiability with lower economic costs.
For the military the reasons for developing Hypersonic vehicles appear to be that speed is seen as the next level of stealth. Also there has been a growing realisation that satellites are not the be all & end all of intelligence gathering as they suffer from both being predictable & vulnerable to increasingly sophisticated anti-satellite weapons. A capability was lost when the SR-71 went away and now maybe that capability is sought again. Once the military have the reason to spend money on this kind of research then hopefully secondary functions such as satellite launch can follow along on the coat tails so too speak.I suspect you could launch a spaceplane something like the XS-1 from the StratoLaunch aircraft. In fact maybe rather than a hypersonic aircraft as launcher but instead it being the payload on a larger carrier aircraft.
Quote from: Star One on 07/02/2014 11:09 pmFor the military the reasons for developing Hypersonic vehicles appear to be that speed is seen as the next level of stealth. Also there has been a growing realisation that satellites are not the be all & end all of intelligence gathering as they suffer from both being predictable & vulnerable to increasingly sophisticated anti-satellite weapons. A capability was lost when the SR-71 went away and now maybe that capability is sought again. Once the military have the reason to spend money on this kind of research then hopefully secondary functions such as satellite launch can follow along on the coat tails so too speak.I suspect you could launch a spaceplane something like the XS-1 from the StratoLaunch aircraft. In fact maybe rather than a hypersonic aircraft as launcher but instead it being the payload on a larger carrier aircraft.The loss of on demand imaging capability that went away when the SR71 was retired was why it was revived for a short time. Historically the process has been (for reconnaissance aircraft) altitude --> speed + altitude + low RCS (but high IR signature) --> altitude +low RCS + low IR (drones).The concept of "responsive space" is an attempt to shift the argument to an "on demand" launch system capable of putting small(ish) pre prepared (possibly modular) satellites) into LEO over a battlefield to give those capabilities Your desire for a high altitude high speed vehicle is frankly fairly unlikely (IMHO) to happen.
Quote from: RanulfC on 07/02/2014 07:43 pmIn general there is little interest in "supersonic" aircraft for civil and military use (the military really only "needs" speed to allow flexible engagement parameters, I.E. you can run when you don't want to fight or engage an enemy who's trying to run away, but the old "Interceptor" role is much less of a priority than manueverability is these days) outside of certain narrow and mostly un-economical uses. Hypersonics is only sees an "possible" should long-distance travel show a very high need for "shorter" travel times. This has actually not been the case since telecommunications allow almost as much flexiability with lower economic costs.It's a very interesting point. How well you build a LV that slots into (or onto) an existing aircraft with minimal (ideally zero) modification. It seems there are so few big freighters with a rear openable payload door in flight.
In general there is little interest in "supersonic" aircraft for civil and military use (the military really only "needs" speed to allow flexible engagement parameters, I.E. you can run when you don't want to fight or engage an enemy who's trying to run away, but the old "Interceptor" role is much less of a priority than manueverability is these days) outside of certain narrow and mostly un-economical uses. Hypersonics is only sees an "possible" should long-distance travel show a very high need for "shorter" travel times. This has actually not been the case since telecommunications allow almost as much flexiability with lower economic costs.
Outside of aircraft you're back to cutting development cost by going to a stripped down LAP concept.
WASHINGTON — The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.
As good a place as any to put this.QuoteWASHINGTON — The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.http://www.spacenews.com/article/military-space/41161afrl-to-establish-new-hypersonics-facility-at-arnold
Quote from: Star One on 07/08/2014 07:12 pmAs good a place as any to put this.QuoteWASHINGTON The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.http://www.spacenews.com/article/military-space/41161afrl-to-establish-new-hypersonics-facility-at-arnoldA new hypersonics research programme.Who knows? In 50 years of tests of SCramjets they've got to 6 minutes of positive thrust.We'll have to see if this turns out to be another money pit.
As good a place as any to put this.QuoteWASHINGTON The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.http://www.spacenews.com/article/military-space/41161afrl-to-establish-new-hypersonics-facility-at-arnold
WASHINGTON The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.
"Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.
Quote from: john smith 19 on 07/08/2014 07:51 pmQuote from: Star One on 07/08/2014 07:12 pmAs good a place as any to put this.QuoteWASHINGTON The U.S. Air Force Research Lab (AFRL) is planning a new hypersonic research branch at Arnold Air Force Base in Tennessee as the service ratchets up its development of an alternative to rocket-powered launchers and high-speed vehicles, according to a July 3 press release from the service.http://www.spacenews.com/article/military-space/41161afrl-to-establish-new-hypersonics-facility-at-arnoldA new hypersonics research programme.Who knows? In 50 years of tests of SCramjets they've got to 6 minutes of positive thrust.We'll have to see if this turns out to be another money pit. "Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.Randy
I really doubt that will be the case, looking at how things have gone in this area.
Quote from: Star One on 07/09/2014 06:24 amI really doubt that will be the case, looking at how things have gone in this area.Perhaps you could expand that comment?
Quote from: RanulfC on 07/08/2014 08:50 pm"Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.Perhaps they might call it the "Skylon Lab?"Just kidding of course. But that makes it look a lot more viable than what's happened historically.
"Branch" not programme. Means that there will be an actual "office" (and personnel) tasked with keeping track of and intergrating data from various hypersonics work. I'm suspecting this is going to be the "liason" office that works with REL actually.Randy
Oh? When did I miss a Skylon flight over Mach 3? (Even an airframe completed sitting on the ground, actually, but we're talking about flight test success.) How many of those six minutes of successful flight has REL / Skylon contributed? I'm continually amazed at how this forum picks "winners" and losers completely unrelated to actual, you know, wins and losses.Maybe we can pick up this discussion in 2019 or so when (perhaps) Skylon will be ready to test themselves against actual hypersonic conditions.Meaning no disrespect to Skylon--they are a talented and potentially wonderful newcomer, and maybe in time they will do great things. Until then, six minutes of powered hypersonic experience trumps zero minutes in the accomplishment category.
Well would you say practical Hypersonic research in the US has had a positive outcome of late?
Unless you're going to follow the assumption I believe that some small number of individuals make that all the best stuff is classified. Such claims I would treat with an extremely high degree of scepticism.
It's good they have set a place like this up, just that I will keep my expectations low and hope to be pleasantly surprised.
What is your thinking here?
Maybe we can pick up this discussion in 2019 or so when (perhaps) Skylon will be ready to test themselves against actual hypersonic conditions.
Meaning no disrespect to Skylon--they are a talented and potentially wonderful newcomer, and maybe in time they will do great things. Until then, six minutes of powered hypersonic experience trumps zero minutes in the accomplishment category.
(Incidentally, I'm speaking as a bystander, not affiliated with AFRL or AEDC.)
While the Air Force is expected to soon issue a request for proposals for its long-range strike bomber, a July 2 Congressional Research Service report made public Tuesday suggests that the service has already developed the aircraft through its classified budget.The CRS report also indicated the new bomber may not even be a single aircraft, but is perhaps several aircraft working together. “Although long-range strike systems are typically thought of as bomber aircraft, the more general description is used because it is not yet clear whether the proposed Long Range Strike Bomber (LRS-B) is to be a single platform or a group of smaller systems working in concert,” CRS reported.
Looks like we may now have a choice of potential candidate vehicles for the purpose of replacing the F-15 at the very least in the ALASA program down the line. If the F-15 is retired from the frontline I assume it will be replaced in this program as well?
Which it will be noted in the second report (and patent) that it was proposed to air-drop it from a C-130J (as well as off the back of an SR-71 ) and using a Rocket-Based-Combined-Cycle (RBCC) engine module allow it to fly at high-supersonic and hypersonic speeds. At least this would allow (even if unmanned) a SERIES of engine tests with various types of engines rather than picking "one" and ending up with either a success or failure.
There is seriously a lot more hypersonic research that the US could be doing but funding is so spotty and interest so fickle that getting anything done is pretty much a matter of luck more than anything else
In order to prove that the MDP metholody works, the team agreed to develop materials that can withstand extreme heat for the outer shell of a hypersonic aircraft, as it can travel more than five times the speed of sound. The group needs to be done within the next two-and-a-half years for the program's method to be deemed successful, so watch out for any hypersonic plane news from DARPA in 2016 or 2017.
Some more hypersonic related information.https://www.fbo.gov/index?s=opportunity&mode=form&id=98ad53aa422228aa7fcd190c08b9653a&tab=core&_cview=0
Quote from: Star One on 07/16/2014 03:03 pmSome more hypersonic related information.https://www.fbo.gov/index?s=opportunity&mode=form&id=98ad53aa422228aa7fcd190c08b9653a&tab=core&_cview=0Great, scramjets again. At least theres some other areas as well.Randy
Quote from: RanulfC on 07/16/2014 03:22 pmQuote from: Star One on 07/16/2014 03:03 pmSome more hypersonic related information.https://www.fbo.gov/index?s=opportunity&mode=form&id=98ad53aa422228aa7fcd190c08b9653a&tab=core&_cview=0Great, scramjets again. At least theres some other areas as well.Yes I agree with you they seem quite stuck on scramjets for some reason.Maybe a follow-on to the Waverider program.
Quote from: Star One on 07/16/2014 03:03 pmSome more hypersonic related information.https://www.fbo.gov/index?s=opportunity&mode=form&id=98ad53aa422228aa7fcd190c08b9653a&tab=core&_cview=0Great, scramjets again. At least theres some other areas as well.
Want to speculate why they are looking at this again if there are alternative concepts for engine technology out there?
The problem though is how fast (and how far) can an OPERATIONAL SCramjet engine really work and is it actually "worth" the trouble? Because every indicator we've seen so far is that a working SCramjet engine is going to be really, really expensive and of doubious use at best. But what is the "alternative" then? Rocket motors are good, so long as the propellant lasts. Ramjets are good up until around Mach-5 then the design gets much tougher, (my contention is that they are LESS tough than SCramjets which is echoed by people who've actually worked on high-speed subsonic combustion ramjets, however...) and you have to get tricky with the inlet and exhausts to keep accelerating which is expensive. (But again I content not as expensive as the marginal SCramjet's have been) And conventional wisdom, (the same one that insisted that the only way to do airbreathing flight at speeds above Mach-5 mind you was to liquify the air and then burn it in a SCramjet to Mach-20+) insits that above Mach-7 a sub-sonic combustion ramjet won't generate positive thrust, and that the internal flow MUST then become supersonic. (Mind that the folks at Mardquart actually ran test engines up to Mach-8+ and the engineers could not see why you couldn't get positve thrust up till Mach-10 if you designed it right. Still that's ONLY Mach-10...)
At the end of the day though the alternatives don't hold that hope of continual accelleration that the SCramjet does so they tend to be considered a "default" rather than an alternative. So SCramjets will continue to get money and development because they ARE SCramjets while the alternatives will get regulated to a backup position that MIGHT get funded if anyone becomes convinced that the laws of physics simply won't allow SCramjets. (In otherwords no one is going to settle for a Mach-10 engine when they MIGHT possibly be able to get a Mach-20 one )I suspect that SCramjets are a whole lot like "fusion" energy, awaiting that next breakthrough that will finally allow them to shine as much in fact as they do in theory... I'm just afraid that it will always be 20 years from today as well:)
The one question for me that is outstanding in this matter is where does LM's engine concept that they were bigging up in Aviation Week in connection with the SR-72 figure in this. They certainly seemed to regard the idea as some kind of breakthrough in achieving hypersonic flight?If there is nothing better out there you would think LM would be banging on the door of government, as the piece in AW seemed to imply that all they lacked was funding.
Aaarrggh! You're building an engine around a duel-mode ramjet... Why again? Lets see if the ramjet kicks in around Mach-4 and its designed at ALL decently it should be then capable of flying to Mach-6 with ease. What's the airframes proposed top speed? Mach-6? Then why the HELL would you even consider putting in a SCramjet you don't even NEED?What? Oh of course, silly me, everyone knows that a hypersonic aircraft has to use a SCramjet engine because ramjets can only go, you know supersonic and not hypersonic well duh...
Oh? When did I miss a Skylon flight over Mach 3? (Even an airframe completed sitting on the ground, actually, but we're talking about flight test success.) How many of those six minutes of successful flight has REL / Skylon contributed? I'm continually amazed at how this forum picks "winners" and losers completely unrelated to actual, you know, wins and losses.
Maybe we can pick up this discussion in 2019 or so when (perhaps) Skylon will be ready to test themselves against actual hypersonic conditions.Meaning no disrespect to Skylon--they are a talented and potentially wonderful newcomer, and maybe in time they will do great things. Until then, six minutes of powered hypersonic experience trumps zero minutes in the accomplishment category.
I recently saw a picture of the SR-71 with the D-21 rocket powered drone on its back and though it's not the same it made me wonder if you could piggyback a launcher for small payloads to LEO on something like the proposed SR-72 hypersonic aircraft. Would there be any advantages to launching from a aircraft at Mach 6 flying at say something like 150,000 feet compared to a more conventional launch aircraft? Or would any advantages be offset by greater difficulties from using such a vehicle.http://www.lockheedmartin.co.uk/us/news/features/2013/sr-72.html
Quote from: Star One on 06/27/2014 06:56 pmI recently saw a picture of the SR-71 with the D-21 rocket powered drone on its back and though it's not the same it made me wonder if you could piggyback a launcher for small payloads to LEO on something like the proposed SR-72 hypersonic aircraft. Would there be any advantages to launching from a aircraft at Mach 6 flying at say something like 150,000 feet compared to a more conventional launch aircraft? Or would any advantages be offset by greater difficulties from using such a vehicle.http://www.lockheedmartin.co.uk/us/news/features/2013/sr-72.htmlAFAIk the D21 was never successfully launched from the SR71. The SR72 is a powerpoint plane at this point. This idea has been discussed at length.
New interview with Marilyn Hewson head of LM & spot how many times she mentions their investment in hypersonics, clue it's quite a few.http://www.c4isrnet.com/article/20140805/C4ISRNET08/308050004/How-Lockheed-Martin-plans-compete-against-Google-Amazon
AFAIk the D21 was never successfully launched from the SR71.
Quote from: Star One on 08/05/2014 06:45 pmNew interview with Marilyn Hewson head of LM & spot how many times she mentions their investment in hypersonics, clue it's quite a few.http://www.c4isrnet.com/article/20140805/C4ISRNET08/308050004/How-Lockheed-Martin-plans-compete-against-Google-AmazonRead it. The answer is 1. on page 3."Hypersonics would be a great example. We have been investing in that for a number of years. "Wasting people's time is not a good way to convince them you know what you're talking about or that it's worth them listening to you.Your choice.
We are always integrating it into our current product lines to keep them relevant, and coming up with new capabilities -- whether directed energy or hypersonics or the advanced materials like nanotechnology or advanced manufacturing and 3-D printing. We are investing to stay current and bring to our customers that innovation that they look for in Lockheed Martin.
Taken from page 2 my bolding. This is the far more interesting quote of the two.Quote We are always integrating it into our current product lines to keep them relevant, and coming up with new capabilities -- whether directed energy or hypersonics or the advanced materials like nanotechnology or advanced manufacturing and 3-D printing. We are investing to stay current and bring to our customers that innovation that they look for in Lockheed Martin.
Quote from: Star One on 08/06/2014 02:27 pmTaken from page 2 my bolding. This is the far more interesting quote of the two.Quote We are always integrating it into our current product lines to keep them relevant, and coming up with new capabilities -- whether directed energy or hypersonics or the advanced materials like nanotechnology or advanced manufacturing and 3-D printing. We are investing to stay current and bring to our customers that innovation that they look for in Lockheed Martin.So two mentions of hypersonics of one line each, in a 4 page reportI stand corrected.
I concede that perhaps I should have empathised the content rather than number in this case.
Quote from: Star One on 08/06/2014 07:03 pmI concede that perhaps I should have empathised the content rather than number in this case.Thank you. The article was a fairly major disappointment. I agree that LM has some interest in hypersonics and think they may have a plan to do it.Time will tell if this actually goes anywhere and if so will it be the son-of-SR71 or NASP II (for those who've read Facing the Heat Barrier that would be NASP III).
Quote from: RanulfC on 07/17/2014 01:52 pmAaarrggh! You're building an engine around a duel-mode ramjet... Why again? Lets see if the ramjet kicks in around Mach-4 and its designed at ALL decently it should be then capable of flying to Mach-6 with ease. What's the airframes proposed top speed? Mach-6? Then why the HELL would you even consider putting in a SCramjet you don't even NEED?What? Oh of course, silly me, everyone knows that a hypersonic aircraft has to use a SCramjet engine because ramjets can only go, you know supersonic and not hypersonic well duh...I'd guess even a conservative approach of regular jet engines would get you to M2.2 or 2.4 and a ramjet to M3 would give you M5.4.
Which I'd call pretty good, but obviously for some people that's just not good enough.
When the history of high speed flight is written I think hypersonic flight --> hypersonic combustion will go down in history with cruise = launch as one of the the great conceptual mistakes in vehicle design.
But of course that won't give you the dream of air breathing to orbit.
But my instinct is that even if you manage to inject your fuel into the airflow with minimal turbulence and you use H2 you just won't inject enough heat to the flow to get enough acceleration before you run out of fuel.
Quote from: john smith 19 on 08/05/2014 09:11 pmAFAIk the D21 was never successfully launched from the SR71. TECHNICALLY correct as the launch aircraft was not the SR-71, but was actually a modified A-12. But...Successful launches were in fact made. As project TAGBOARD, successful launches on-5 March 1966-27 April 1966-16 June 1966Now, overall MISSION success is another matter, but in these instances the LAUNCH itself was successful.30 July 1966 attempt was the D-21 collision with the M-21 (modified A-12) immediately after launch. Pilot Bill Park and Launch Control Officer Ray Torick ejected but Torick drowned after landing in the ocean. After that, the D-21 was modified for launch from the B-52 as project SENIOR BOWL.
I wonder why they feel the need to get it into their interviews if they are not really going to say anything much, other than thinking its good PR.
"Technically, technically" correct (we can do this all day long for a couple of years if you-all want )
Quote from: RanulfC on 08/07/2014 09:31 pm"Technically, technically" correct (we can do this all day long for a couple of years if you-all want )If you wish to argue with my terminology and sources, (Mssrs. Miller and Jenkins et al) and split finer and finer hairs, you're certainly welcome to.
SERIOUSLY "conservative" given a subsonic combustion ramjet designed to have a maxium (sweetspot) speed with a fixed inlet and exhaust of Mach-4 ACCIDENTLY flew to Mach-5.5 (and was still accellerating) when it ran out of fuel with a stuck fuel-valve Seriously, Glenn Olson of "alt-accel.com" noted that there was an abundance of cited work on subsonic ramjet engine operations at speeds up to @Mach-7 for it to be quite logical that engine had in fact been tested to those speeds. He also pointed out (and the owner/operator of "Ex-Rocketmans Take" blog who IS an actual ramjet engine engineer has confirmed) that when interviewing people who worked on and with subsonic ramjet engines none of them saw any major issues to running such engines to speeds in excess of Mach-8. While no one has ever gone "on-record" stating it people who were directly involved in the design, construction and testing of the BOMARC missile engines (Mardquart) to a one would make note that the AIRFRAME of the BOMARC would fall apart around Mach-10 but that the engines would still be working. (Producing no thrust I'm sure and melting in the process but working )
It comes down to what you intent to DO I suppose, the problem is that most people who are "supposedly" working on "hypersonic-flight/propulsion" are really JUST working on SCramjets and to heck with any practical or operational considerations
?? Just a note but HYPERSONIC combustion isn't on ANYONES radar or thought pattern! SUPERSONIC combustion has been tough enough I don't think anyone is thinking about making it 5-times hard than it already is
Seriously hypersonic flight which is technically any "flying" at speeds higher than Mach-5 is a "given" for any serious use of airbreathing AND "flying" on the way to orbit. The foremost example being the Skylon An aerodynamic "lifting" trajectory pretty much demands getting to somewhere above Mach-5 before going for orbit where as "just" speaking of something like "launch-assist" anywhere between Mach-0.90 and Mach-5+ all "give" a viable boost to orbital launch. However I have to agree that the "conceptual" direction along with the insistance on SCramjets has been a major road-block on actually DEVELOPING anything for the last 40 years.
THE problem is the folks who are actually getting money and work are NOT the ones who "dream" of air breathing to orbit despite what they say. Those that do are ignored because they don't propose the high-cost, high-profile technology but insist that we can do the job with what amounts to "off-the-shelf" parts and technology
The problem is your "instinct" conflicts with the math and lab testing, it's been "bench" proven to around Mach-7 with hydrocarbon fuels and IIRC Mach-9 with hydrogen but there is a major disconnect between what seems to work in the lab and the same thing working in the "real-world"
Again the MATH and THEORY "prove" that using hydrogen you can get a SCramjet to air-breath past Mach-25 and still manage to get positve heat injection. (Going out a long way on a short limb of memory IIRC the supersonic flow of air at the speed of Mach-25 is less than the temperature reached by some of the Nuclear heating test elements for the very late NERVA program which is what pretty much proves the idea will "work" except for the whole disturbance during the fuel injection and no one getting a SCramjet to work at speeds as high as Mach-12+ let alone Mach-25... It's just "simple" engineering right? )
But in the end the "math-and-theory" ignore everything in front of and behind the combustion chamber of the SCramjet and simply "assume" that everything works to get to point-Z without "bothering" with points A-through-X... Refer back to it being "engineering" and not something to worry about...
The advocates make it SOUND so simple while PROMISING so much and waving that pretty-pretty math/theory will poo-pooing the people who try and point out the man behind the curtain, the curtain, the building and the city needed to support it all. And they make it SOUND so damn good no one who suggests doing it with what is available and practical are either ignored or worse for suggesting NOT going for the "best" solution. It just doesn't make any SENSE to me...
<brief history of A12/SR71/D21 programme snipped>
Somewhere (tm) I have a NASA report/study where they were looking at using the SR-71s to launch a large multi-propulsion type drone for studying hypersonic flight. They specifically addressed the M-21/D-21 accident and noted that while the majority of launches were successful the flights were not but this had nothing to do with the launch METHOD and even after TAGBOARD was transfered to B-52/C-130 (SENIOR BOWL) launches the autopilot of the D-21 was never gotten to the level of reliabilty needed for the safety of M-21. It was a known fault, and the fact that even when launched subsonic with rocket boost the autopilot was the part of the system that most often failed was never really resolved. (The accident, just to be clear was NOT caused by the drone "bouncing" off the supersonic shockwave but by the D-21 autopilot suddenly commanding the D-21 into a dive which caused it to collide with the M-21)In another study I have (somewhere, tm ) where its proposed to take a "stock" D-21 and turn it into a hypersonic engine test bed the FIRST thing that is discussed is the REPLACEMENT of ALL the electronics for modern WORKING (and that's capitalized in the report in places as well ) flight controls
Quote from: DMeader on 08/07/2014 11:52 pmQuote from: RanulfC on 08/07/2014 09:31 pm"Technically, technically" correct (we can do this all day long for a couple of years if you-all want )If you wish to argue with my terminology and sources, (Mssrs. Miller and Jenkins et al) and split finer and finer hairs, you're certainly welcome to.Not at all and not "arguing" really just pointing out finer detail because lets face it everyone loves the SR-71 right As an aside but in the general direction of the thread, at one point it was "suggested" that the M-21 could be replaced with a varient of the B-58 then being retired as the D-21 and a smaller booster rocket could be used in place of the usually carried pod. "Suggested" was as far as it ever got (a memo IIRC) because it was pointed out that unlike the aft-upper-side environment of the M-21 the under-side-center-line set up would not allow the D-21 ramjet to start properly. It was also pointed out that the B-58 was being retired due to wing-box cracking so most aircraft were going to be no longer operational anyway.Randy
It's also why I believe there is a constant belief in certain quarters that a replacement for the SR-71 must either be in use or at hand and why something like the urban legend of the Aurora gained so much traction online and has hung around so long.
I found this photo on the Internet some a few months ago.
Which reminds me IIRC the engines on the XB70 were not particularly exotic, although pretty big. Once compression lift was discovered no one seemed to doubt it could fly the mission without any kind of special fuel or ramjet nacelle design.
Having read into the history I'd always thought the A12 came first (for the CIA) and then transitioned into the SR71 for the USAF. I was aware that their were plans for versions to carry AAM's (including nuclear warheads) and KE penetrators to hit very hard targets but I did not realize all of them had that dorsal hard point (I though it was a special mod for the D21 carriage).
Frankly the whole auto pilot/nav package seems a bit of a lemon (although for 1cu ft in the early 60's it was probably pretty impressive). It also used the "stacked cordwood" method of direct spot welding parts together without PCBs, which made repairs a royal PITA. BTW There are still a bunch of these mothballed in the aircraft storage area out in the desert.
And a note on my terminologyFor people unaware of the original Aerospace Plane of the early 60's this latest proposal could be seen as "NASP II" but in reality it is NASP III, although I'm presuming LM want it to turn out more like the original SR71 programme.Time will tell if either of these visions comes true.
It's my belief that one of the reasons that there is so much interest out there in hypersonic flight (or I should say aircraft that fly exceptionally fast) amongst the general public is the high regard the SR-71 is held in. Look at the fuss that brewed up when the SR-72 concept was announced.
A very recent example of how over-excited people get about hypersonic and related projects, see the article below. You have to kind admire all the old aviation projects dragged up in it including the XB-70 mentioned up thread.http://foxtrotalpha.jalopnik.com/new-panoramic-images-show-area-51-s-new-mystery-hanger-1628823466Strangely no mention of the two most likely opinions that it is another scoot and hide shelter or it's for the Speed Agile project but I suppose they are both too boring to mention.
I like the concept of a hypersonic aircraft for LEO launcher on paper, but I've never seen any accounting math which tells me it'd be worth it.
The difference in starting airspeed per dollar spent on development and operations for the a rocket which launches from a hypersonic carrier aircraft versus a larger rocket which launches from a subsonic carrier aircraft is the relevant cost delta. Everything else is an ignored cost.
In other words, for the exact same payload to orbit, is it cheaper to slap on a bigger solid motor and develop a larger subsonic carrier aircraft than it is to develop a hypersonic aircraft that air launches a smaller rocket.
So far, the answer appears to be that it's cheaper to use a slower, but larger aircraft to carry a larger rocket than it is to develop a faster aircraft with a smaller rocket. I'd postulate that with solid propellants, it's vastly cheaper. The Pegasus booster and the Strato-Launch concepts are betting their business models on it. Nothing's ever been built using the hypersonic carrier business model, so perhaps it's just vaporware as far as the business model is concerned.
Now, in terms of non-economic considerations, such as military applications, there may be some valid mission-oriented rationale for developing that hypersonic carrier aircraft, but honestly, I can't think of any missions where the immediate need to orbit a spacecraft (versus blowing one up) is so great that it couldn't wait a few more minutes to be launched from a sub-sonic aircraft or surface-launched booster.
Reheated here; http://robotpig.net/__aerospace/tsto.php?page=1
Quote from: Stellar_Speedster on 11/18/2014 05:34 pmReheated here; http://robotpig.net/__aerospace/tsto.php?page=1 That's supersonic actually It doesn't get past Mach-4 with the carrier aircraft and "hypersonic" is above Mach-5 just FYI The patent you post is for this same system btw. In reality if you use a 'steam-catapult' or rail system you would probably lose the jet engines as they are fulfilling the same role of getting the vehicle into the stratosphere. But you also lose a great deal of fleixabilty in trajectory by limiting yourself to a single launch point.This is probably one of the better air-breathing launch vehicle designs out there IF you insist on having a full-up carrier vehicle for what amounts to an "assisted" Single Stage To Orbit orbital vehicle. It's based on initial work done under the BETA and BETA-II concept study:http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920002777.pdfhttp://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920012293.pdfWhich WAS a hypersonic design but found to be much more costly to build than initially thought mostly BECAUSE it was a hypersonic design Personally I think you could about half the vehicle(s) sizes if you went with methalox rather than hydrolox which would reduce your construction costs by a lot. Even better was the SpaceJet Concept:http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810020560.pdfhttp://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790015826.pdfhttp://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19780003229.pdfhttp://crgis.ndc.nasa.gov/historic/File:L-79-965.jpghttp://www.secretprojects.co.uk/forum/index.php?topic=11026.0http://www.up-ship.com/eAPR/images/art33ani.jpgWhich reduced the "carrier-aircraft" to flyback engine pods... Or you COULD simply go with JUST jet-engine pods launch assist... But that's a different thread Randy
Yes Randy interesting reading !I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.That might need another thread.
Quote from: Stellar_Speedster on 11/19/2014 07:51 pmYes Randy interesting reading !I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.That might need another thread.Look it up before you do though, I REALLY think "rail-launch-up-a-mountain-side" has been done before... A LOT Randy
Quote from: RanulfC on 11/19/2014 08:08 pmQuote from: Stellar_Speedster on 11/19/2014 07:51 pmYes Randy interesting reading !I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.That might need another thread.Look it up before you do though, I REALLY think "rail-launch-up-a-mountain-side" has been done before... A LOT RandyRandy, Were they using lubbed rails or Magnetic Levitation track? I can see only getting to Mach 1.5 on Lubbed rails But mag levs ought to get phenominal velocity going up a mountain.
Quote from: RanulfC on 11/19/2014 08:08 pmQuote from: Stellar_Speedster on 11/19/2014 07:51 pmYes Randy interesting reading !I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.That might need another thread.Look it up before you do though, I REALLY think "rail-launch-up-a-mountain-side" has been done before... A LOT Randy, Were they using lubbed rails or Magnetic Levitation track? I can see only getting to Mach 1.5 on Lubbed rails But mag levs ought to get phenominal velocity going up a mountain.
Quote from: Stellar_Speedster on 11/19/2014 07:51 pmYes Randy interesting reading !I guess you are right...jet propelled rail launch to mach 1.5 at 15 000 ft on a mountain side..then two stage to orbit system both rocket propelled.That might need another thread.Look it up before you do though, I REALLY think "rail-launch-up-a-mountain-side" has been done before... A LOT
I seem to recall a documentary about a rocket sled run at IIRC Los Alamos. The rig ran (at Sea Level) up to somewhere around M4-M6, although I think they were running it through a Helium filled tunnel (like a large garden cloche) to change the speed of sound. The capabilities of leading edge systems built for special purpose can far outstrip the level of standard systems (although the price is likely to be pretty steep).
How fast is the speed of sound in Helium ?
NASA has awarded a contract to Lockheed Martin to study the feasibility of building a hypersonic propulsion system for a concept intelligence, surveillance and reconnaissance (ISR) aircraft dubbed the SR-72 using existing turbine engine technologies.The $892,292 contract “provides for a parametric design study to establish the viability of a turbine-based combined cycle (TBCC) propulsion system consisting of integrating several combinations of near-term turbine engine solutions and a very low Mach ignition Dual Mode RamJet (DMRJ) in the SR-72 vehicle concept,” the award document says.If the study is successful, NASA wants to fund a demonstration programme. Lockheed would test the dual-mode ramjet in a flight research vehicle, and try to find solutions to issues like engine packaging and designing the thermal management system, Bartolotta says.“We’re doing this at a lower Mach number so we need to figure out what are the issues for cocooning the turbine, what do we need to do to reignite that turbine once we come down from hypersonic speeds,” Bartolotta says.
Over the past year Skunk Works has invited a few journalists to its most secure facilities, including Palmdale, a site in the high desert 60 miles (100 km) from Los Angeles, where new products range from next-generation unmanned systems to a hypersonic aircraft twice as fast as its Blackbird SR-71 spy plane that could fly across country in just over an hour.
New article from Flight Global.NASA launches study for Skunk Works SR-72 concept.QuoteNASA has awarded a contract to Lockheed Martin to study the feasibility of building a hypersonic propulsion system for a concept intelligence, surveillance and reconnaissance (ISR) aircraft dubbed the SR-72 using existing turbine engine technologies.http://www.flightglobal.com/news/articles/nasa-launches-study-for-skunk-works-sr-72-concept-407222/
NASA has awarded a contract to Lockheed Martin to study the feasibility of building a hypersonic propulsion system for a concept intelligence, surveillance and reconnaissance (ISR) aircraft dubbed the SR-72 using existing turbine engine technologies.
Quote from: Star One on 12/18/2014 03:34 pmNew article from Flight Global.NASA launches study for Skunk Works SR-72 concept.QuoteNASA has awarded a contract to Lockheed Martin to study the feasibility of building a hypersonic propulsion system for a concept intelligence, surveillance and reconnaissance (ISR) aircraft dubbed the SR-72 using existing turbine engine technologies.http://www.flightglobal.com/news/articles/nasa-launches-study-for-skunk-works-sr-72-concept-407222/I'm dubious (to be polite) that NASA would award a contract for this purpose. This is Air Force territory, not civilian aerospace.More likely is the article got it wrong, and the contract is simply for further development of a supersonic civilian concept.You only need speed if you aren't supposed to be over the particular patch of territory you are trying to image....
Well until I see something to the contrary I'm going to take the article at face value as their usually a reputable source of news.
Quote from: Star One on 12/19/2014 03:50 pmWell until I see something to the contrary I'm going to take the article at face value as their usually a reputable source of news.The article talks about ramjets not being able to ignite below M4.0.This is incorrect. The BOMARC and Talos ramjet missile programmes fielded 100s of missiles each, all running below M4.0.It appears the author has confused supersonic combustion (SC)ramjets with ordinary ramjets.Which straightaway makes there grasp of the subject look very shaky.
I'm not sure you can use that example as its a missile engine and as you very well should know a missile engine is a very different prospect than an aircraft engine. A missile engine is usually only required for a relatively short space of time propelling an object far smaller than an aircraft.
For example the infamous pulse detention engine can be used for missiles but it doesn't mean it's appropriate for an aircraft. So for the author to say this in terms of aircraft propulsion seems entirely in order.
Quote from: Star One on 12/20/2014 08:52 amI'm not sure you can use that example as its a missile engine and as you very well should know a missile engine is a very different prospect than an aircraft engine. A missile engine is usually only required for a relatively short space of time propelling an object far smaller than an aircraft. The physics of a ramjet don't care if it's sitting on a crewed vehicle or a drone. It is factually wrong that a ramjet cannot be ignited below M 4.0. My guess is the author has confused a ramjet with a scramjet. Something anyone with some familiarity with the subject would never do. QuoteFor example the infamous pulse detention engine can be used for missiles but it doesn't mean it's appropriate for an aircraft. So for the author to say this in terms of aircraft propulsion seems entirely in order.AFAIK the first flight test for a PDE was a crewed aircraft. In fact a PDE should be more flexible than a ramjet as some of its parameters are easier to vary. You need to do more reading around this technology.
I'm somewhat bemused that you think that just because technology works on a missile that it means it's appropriate for an aircraft. If it was that easy I'm sure we would have had hypersonic aircraft by now.
Quote from: john smith 19 on 12/20/2014 11:24 amThe physics of a ramjet don't care if it's sitting on a crewed vehicle or a drone. It is factually wrong that a ramjet cannot be ignited below M 4.0. I'm somewhat bemused that you think that just because technology works on a missile that it means it's appropriate for an aircraft. If it was that easy I'm sure we would have had hypersonic aircraft by now.
The physics of a ramjet don't care if it's sitting on a crewed vehicle or a drone. It is factually wrong that a ramjet cannot be ignited below M 4.0.
I'm somewhat bemused that you are purposefully refusing to understand what John is saying. He is correct, the engine doesn't know or care what sort of aircraft it is attached to. What is "appropriate" is an entirely different matter and outside the scope of this discussion.
Quote from: DMeader on 12/20/2014 10:26 pmI'm somewhat bemused that you are purposefully refusing to understand what John is saying. He is correct, the engine doesn't know or care what sort of aircraft it is attached to. What is "appropriate" is an entirely different matter and outside the scope of this discussion.Indeed. It's hard to understand how someone could be so vested in a report (unless the wrote it of course).
I'm not invested in the report or have written it, just that I'd rather give it more weight in this case than some person posting on a forum.As for people finding it funny that NASA should be doing this research for a seemingly military project must have forgotten that NASA Aeronautics & the USAF signed a MOU back in 2006 to as it says on their website: In August 2006, NASA and the U.S. Air Force signed a Memorandum of Understanding (MOU) to formalize a new aeronautics research partnership. The MOU ensures the free exchange of research information, reduces duplication of research, and enhances long-term research planning on advanced aircraft design, propulsion development, materials development, and aviation safety.
There's some legitmate question on the article information but it DOES point out that the main questin is can a duel-mode ramjet start at lower speeds and it should be recalled that for the most part a ramjet has a "range" of about three or so "Mach" above start-up. So a Mach-2.2 ramjet can probably hit Mach-5 HOWEVER SCramjets haven't had a lot of luck getting going well under Mach-6/7 so there is a definate need to "up" the low end of things.
The main "issue" at hand is if a SCramjet is really needed at all for the proposal. Given the "SR-72" as it keeps getting called is supposed to "cruise" at somewhere around Mach-6/7 which a "plain" old subsonic combustion ramjet will handle (granted its got to be designed to START around Mach-4 but we've actually DONE that before ) I have to wonder if the SCramjet is even worth the effort.(And there's the pertent line: “We’re looking for a turbine-based combined system where at low speeds you have a turbine providing power, then at higher speeds a ramjet or scramjet takes over")Mach-4 with a "standard" F100 should be possible with MIPCC for boost and Mach capability increase, a standard subsonic combustion ramjet from there to Mach-7 "cruise" (actually the Mach-7 part is a 'dash' and the vehicle will probably "cruise" supersonic) and then back down to turbine power for return and landing. Still not sure I buy the idea that "hypersonic" is the new stealth though, unless you're coming in below 40,000ft (which at Mach-7 would be a real trick) most radars will still have time to pick you up and generate a tracking solution.
Not much use as a space launcher though
Sorry to interrupt ,I'm looking for the xs1 thread, is it here?
Quote from: RanulfC on 12/22/2014 09:19 pmNot much use as a space launcher though Why is that? Mach 7 at fairly high altitude sounds like it would be a significant delta v gain, likely enough for 1 stage to orbit. Is there just not enough payload for a significant rocket? Or just too expensive?
I think LM are playing a very astute game.
Concorde proved a large turbojet aircraft can super cruise without afterburner for hours at a time without damage at M2.2, and of course the SR71 proved they could run in 'burner for hours at a time too. A range of 3 Mach numbers is well inside the ramjet knowledge base so LM has 3 options.I think it's plausible (although I'm not sure if it's been tested) that the kind of military low BPR turbofans the military favor can survive up to M2.2 as well. So M6 - M3 - M2.2 = M0.8So (in principle) what's needed is some way to bridge that extra M0.8. Drop the SCramjet ignition speed, widen the ramjet operating speed range, or a bit of both, and hey presto you're home free. While thinking about this problem I will note there is a non obvious split in the engine duties. Instead of turbo-something and ram/SCramjet how about subsonic and non subsonic inlets?In this view the flow path starts without slowing the flow and has some kind of diverter arrangement (I'm thinking like a set of louvres).At low speed the louvres are at (relatively) high angle and direct the flow into the turbine/ramjet section, with it's associated shock paths, flame holders etc. At higher speed the blades flatten out to horizontal and point the flow at the SCramjet path, simultaneously directing the now very hot air stream straight into the SCRamjet duct with minimal drag. It all sound desperately complicated to me but it might work. I'd like to think they've come up with some elegant, tricky fluidic solution (something exploiting the Coanda effect?) but fluid dynamics is not really my strong suite. BTW would you say M6 is above the point where the engine and the vehicle have to be designed together or can they still get away with "dropping in" an engine package? I don't think they can. I also think they'll need to go to higher altitude to sidestep (partly) the heating issues. 80 000 ft?Whatever the solution it's pretty clear this is not going to be cheap.
If the hypersonic aircraft can do do a pull up maneuver and get past or at at least close to the Kármán line separation of the upper stage could be relatively strait forwards and much simpler then it would be for a supersonic aircraft. Because the problem of shock interaction during separation would be eliminated.
Quote from: Patchouli on 12/24/2014 06:51 pmIf the hypersonic aircraft can do do a pull up maneuver and get past or at at least close to the Kármán line separation of the upper stage could be relatively strait forwards and much simpler then it would be for a supersonic aircraft. Because the problem of shock interaction during separation would be eliminated.The "idea" is used with supersonic seperation as well. RASCAL was only supersonic (little over Mach-1.5 at seperation) but did a "zoom" climb to allow low-Q seperation. The main issue is most of your air-breathing power plants will quit working well below the Karman line and you lose a great deal of velocity between engine cut off and seperation. Granted you START with more being hypersonic (Mach-5+) but still speed bleeds off pretty quickly.It's one (of the many) reasons why the idea of a non-airbreathing "secondary" component propulsion system is often seen in these ideas. (Normally a "secondary" rocket propulsion system but also why you see rocket-based-combined cycle powerplants suggested. The "rocket" portion continues to operate after the air-breathing system shuts down and being a "combined" powerplant means its slightly less massive than two seperate power plant systems)Randy
In relation to this why is NASA giving money to LM to study an engine concept in this area, shouldn't it be the USAF's money? I know as I mentioned above that NASA Aeronautics works with the USAF, but it still seems mildly strange. If it goes beyond a concept study surely NASA are not going to start funding that as well.
Quote from: Star One on 12/30/2014 04:44 pmIn relation to this why is NASA giving money to LM to study an engine concept in this area, shouldn't it be the USAF's money? I know as I mentioned above that NASA Aeronautics works with the USAF, but it still seems mildly strange. If it goes beyond a concept study surely NASA are not going to start funding that as well. Look at the amount of money cited, less than 900 thousand for a "parametric feasability" study which has pretty much been "done" to death already... The award is justifiable under the NASA "aeronautics" propulsion mandate but probably barely. At a guess here I'm thinking this is an "offset" look at possible near-term propulsion concepts to be mated with the DMRJ described and very much less anything aimed at actually achieving anything equipment wise. (IIRC this is around the same "price" range that AFIT is spending on the proposed study of the SABRE cycle from REL so I'm guessing this is the SCramjet folks response to that engine work. After all we all KNOW how superior a Mach-7+ SCramjet engine is going to be to any thing as "piddly" as a Mach-5 engine right? We just need to keep hammering that "possibility" over the heads of anyone who insists on something that might actually, you know, work anytime in the near future Randy
In your opinion do you think this is the last we'll hear of this particular approach?
You're of the view that it's unlikely too result in actual metal being bent on some kind of propulsion demonstrator?
Thanks for the comprehensive response. Are you disappointed to see NASA using their money on something like this. I know it's not much money in the grand scheme of things but I'd rather see someone like DAPRA or the Air Force funding this not NASA.
By the way when you talk of the SR-72 already being mothballed were you thinking of the Blackswift project here which it doesn't seem that dissimilar from in concept.
I think the best approach to this whole idea would be a 'mothership' aircraft with some kind of parasite vehicle being the actual launcher & achieving hypersonic flight.
Quote from: Star One on 12/30/2014 09:04 pmThanks for the comprehensive response. Are you disappointed to see NASA using their money on something like this. I know it's not much money in the grand scheme of things but I'd rather see someone like DAPRA or the Air Force funding this not NASA.It's hard to be "diappointed" with NASA doing its job and paying for aerospace research. I would feel much better if the project seemed to have any chance of actually producing some flight hardware, and/or wasn't "tied" to having to use SCramjets in any way but...I think DARPA has its hands full at the moment with the XS-1 project and I don't see the AF stepping in until there is some clear indication that the system could be made operational.QuoteBy the way when you talk of the SR-72 already being mothballed were you thinking of the Blackswift project here which it doesn't seem that dissimilar from in concept.Blackswift was in fact mentioned as being a "precursor" of the SR-72 concept but I was more refering to references from early last year where DARPA had dropped work on the concept and the AF had declined to pick it up. As far as I can tell while this sort of stuff keeps the "concept" on life support it doesn't seem to indicate any significant work is being done.QuoteI think the best approach to this whole idea would be a 'mothership' aircraft with some kind of parasite vehicle being the actual launcher & achieving hypersonic flight.Depends greatly on which "idea" one is pursuing I'd agree in most cases you want a smaller, (less expensive) vehicles for the "mission" of recon and/or strike and probably, prefeably exendable ones at that. However if the "idea" is to find an excuse to use SCramjets for some purpose at all.... Randy
I'm getting kind of tired of the whole hypersonic aircraft as a concept in this context. You kind of feel like saying either commit to develop related hardware or just let the whole thing die and stop resurrecting it under different names or at the very least adopt a more flexible approach in which they consider different technologies to achieve their aims.
DARPA Seeks Increased Spending For Hypersonic Air-Breathing ProgramThe Pentagon's advanced research arm seeks a nearly eight-fold funding increase in fiscal year 2016 on a joint program with the Air Force that focuses on flight demonstrations of critical hypersonic technologies.
Would any of the early STS proposals which included flyback boosters be considered a hypersonic aircraft?
This is probably more applicable here than elsewhere. Annoyingly I cannot give you a direct link to the rest of the article as its on a pay site just the abstract on their public side.QuoteDARPA Seeks Increased Spending For Hypersonic Air-Breathing ProgramThe Pentagon's advanced research arm seeks a nearly eight-fold funding increase in fiscal year 2016 on a joint program with the Air Force that focuses on flight demonstrations of critical hypersonic technologies.But I imagine it was taken from this. See page 213 onwards.http://www.darpa.mil/WorkArea/DownloadAsset.aspx?id=2147488711
Quote from: Star One on 02/18/2015 02:08 pmThis is probably more applicable here than elsewhere. Annoyingly I cannot give you a direct link to the rest of the article as its on a pay site just the abstract on their public side.QuoteDARPA Seeks Increased Spending For Hypersonic Air-Breathing ProgramThe Pentagon's advanced research arm seeks a nearly eight-fold funding increase in fiscal year 2016 on a joint program with the Air Force that focuses on flight demonstrations of critical hypersonic technologies.But I imagine it was taken from this. See page 213 onwards.http://www.darpa.mil/WorkArea/DownloadAsset.aspx?id=2147488711Lost interest the second they invoked "SCramjet" technology for the HAWC missile The TBG is interesting as its a "boosted" hypersonic glider but since its using rockets to get to hypersonic speed it has limited applicability.Randy
SCramjets look SO good in theory.. Reality has a bad tendency to get in the way though I'd found a nice study on advanced ramjets at a collage library one time that pointed out that it past a certain speed even a SCramjet doesn't work because of physics so getting to orbit with one it right out the window. (Somewhere around Mach-15 IIRC the airflow becomes hot enough that even injecting hydrogen doesn't work to increase the flow energy. Randy
Quote from: RanulfC on 02/19/2015 08:19 pmSCramjets look SO good in theory.. Reality has a bad tendency to get in the way though I'd found a nice study on advanced ramjets at a collage library one time that pointed out that it past a certain speed even a SCramjet doesn't work because of physics so getting to orbit with one it right out the window. (Somewhere around Mach-15 IIRC the airflow becomes hot enough that even injecting hydrogen doesn't work to increase the flow energy. RandyYou may have ruled out SSTO SCramjets as feasible; maybe not. But pro engineers (don't know if you are one)always find a solution if physics allows. Tunnel vision opinions tend to ignore workaround solutions like converting part of the air sucked in to temporarily stored oxidizer (LOX); or making a hybrid propulsion system, etc.