Comments on: Feeding the Turborocket http://selenianboondocks.com/2009/07/feeding-the-turborocket/ Random Musings from the Warped Minds of Jonathan Goff, Ken Murphy, John Hare, and Kirk Sorensen Thu, 26 Jan 2012 21:26:05 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: john hare http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-7310 john hare Thu, 04 Feb 2010 08:41:14 +0000 http://selenianboondocks.com/?p=1099#comment-7310 Carlos, I just glanced at the first page or so in the link and don't have time to fully check it out now. I'll respond in a few days when I get back in town. Carlos,

I just glanced at the first page or so in the link and don’t have time to fully check it out now. I’ll respond in a few days when I get back in town.

]]> By: Carlos Barrera http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-7303 Carlos Barrera Wed, 03 Feb 2010 21:11:47 +0000 http://selenianboondocks.com/?p=1099#comment-7303 Check this turboflow option (liquids & gas): The Imploturbocompressor. And I have other project, the Gearturbine, details at: Tip Info / New Technology Submission - Gearturbine - Atypical http://gearturbine.260mb.com/ YouTube Video; Atypical New * GEARTURBINE / Retrodynamic GEARTURBINE -Atypical Combustion Turbine Engine, -State of the Art, -New Thermodynamic Technology, -With Retrodynamic "Dextrogiro vs Levogiro" Effect, is when the inflow direction moves is against of the circular rotary dynamic, RPM Rotor Move VS Inflow Conduits Way, making in a simple way a very strong concept of power thrust, a unique technical cuality. -Non Waste, parasitic losses form-function engine system for; cooling, lubrication & combustion; -Lubrication & Combustion inside a conduit radial position, out way direction, activated by centrifugal force (centrpetal to in), -Cooling in & out; In by Thermomix flow & Out by air Thermo transference, activated by the dynamic rotary move, -Increase the first compresion by going of reduction of one big circunference fan blades going to, -2two very long distance cautive compression inflow propulsion conduits (like a digestive system) (long interaction) in perfect equilibrium well balanced start were end like a snake bite his own tale, -Inside active rotor with 4 pairs of retrodynamic turbos (complete regeneration power system), -Mechanical direct "Planetary Gear" power thrust like a Ying Yang (very strong torque) (friendly loose friction) 2two small gears in polar position inside a bigger shell gear, wide out the rotor circunference were have much more lever power thrust, lower RPM in a simple way solution for turbines, to make posible for a some new work aplication (land). -3 Stages of inflow turbo compression before the combustion. -3 points united of power thrust; 1- Rocket Flames, 2-Planetary Gear & 3-Exhaust Propulson, all in one system. -Combustion 2two continue circular moving inside rocket Flames, like two dragons trying to bite the tail of the opposite other. -Hybrid flow system diferent kind of aerolasticity thermoplastic inflow propulsion types; single, action & reaction turbines applied in one same system, -Military benefits, No blade erosion by sand & very low heat target profile. -Power thrust by barr (tube); air sea land & generation aplication, -With the unique retrodynamic technical cuality of "dextrogiro vs levogiro" effect is when the inside flow moves against of the rotor moves making a very strong concept, RPM Rotor Move VS Inflow Conduits Way (an a example is like to move the head to the side of the strike ponch) -A pretender of very high % efficient power plant looking to make posible a cheap electrolysis. -Patent; Dic 1991 IMPI Mexico #197187 Check this turboflow option (liquids & gas):
The Imploturbocompressor.
And I have other project, the Gearturbine, details at:

Tip Info / New Technology Submission – Gearturbine – Atypical

http://gearturbine.260mb.com/

YouTube Video; Atypical New * GEARTURBINE / Retrodynamic

GEARTURBINE -Atypical Combustion Turbine Engine, -State of the Art, -New Thermodynamic Technology, -With Retrodynamic “Dextrogiro vs Levogiro” Effect, is when the inflow direction moves is against of the circular rotary dynamic, RPM Rotor Move VS Inflow Conduits Way, making in a simple way a very strong concept of power thrust, a unique technical cuality. -Non Waste, parasitic losses form-function engine system for; cooling, lubrication & combustion; -Lubrication & Combustion inside a conduit radial position, out way direction, activated by centrifugal force (centrpetal to in), -Cooling in & out; In by Thermomix flow & Out by air Thermo transference, activated by the dynamic rotary move, -Increase the first compresion by going of reduction of one big circunference fan blades going to, -2two very long distance cautive compression inflow propulsion conduits (like a digestive system) (long interaction) in perfect equilibrium well balanced start were end like a snake bite his own tale, -Inside active rotor with 4 pairs of retrodynamic turbos (complete regeneration power system), -Mechanical direct “Planetary Gear” power thrust like a Ying Yang (very strong torque) (friendly loose friction) 2two small gears in polar position inside a bigger shell gear, wide out the rotor circunference were have much more lever power thrust, lower RPM in a simple way solution for turbines, to make posible for a some new work aplication (land). -3 Stages of inflow turbo compression before the combustion. -3 points united of power thrust; 1- Rocket Flames, 2-Planetary Gear & 3-Exhaust Propulson, all in one system. -Combustion 2two continue circular moving inside rocket Flames, like two dragons trying to bite the tail of the opposite other. -Hybrid flow system diferent kind of aerolasticity thermoplastic inflow propulsion types; single, action & reaction turbines applied in one same system, -Military benefits, No blade erosion by sand & very low heat target profile. -Power thrust by barr (tube); air sea land & generation aplication, -With the unique retrodynamic technical cuality of “dextrogiro vs levogiro” effect is when the inside flow moves against of the rotor moves making a very strong concept, RPM Rotor Move VS Inflow Conduits Way (an a example is like to move the head to the side of the strike ponch) -A pretender of very high % efficient power plant looking to make posible a cheap electrolysis. -Patent; Dic 1991 IMPI Mexico #197187

]]> By: John Bossard http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-5252 John Bossard Thu, 23 Jul 2009 16:25:06 +0000 http://selenianboondocks.com/?p=1099#comment-5252 A great post, John. As you discuss in your post, inlets for airbreathing engines, especially for high speed flight, are indeed a central issue, and pose some of the most difficult technological challenges for efficient airbreather operation. The issues only get more difficult as the flight speeds increase. Inlets play a central role in recovering total pressure from the free stream conditions, and as my old turbomachinery professor told us, “The total pressure through the engine (airbreather) is a fundamental performance parameter”, or words to that effect. If you can’t recover the total pressure, you can’t make thrust, no matter how hot you make the gas. There are a number of different definitions or conventions that one can use to quantify the performance of the inlet. In modeling I've done, we often use simply an empirically derived pressure-recovery schedule, which specifies the ratio of recovered stagnation pressure to freestream stagnation pressure as a function of free stream mach number. An analytic function that is reasonable and robust is the use of the so-called kinetic energy efficiency, as given by Kerrebrock (Aircraft Engines and Gas Turbines, J.L. Kerrebrock. ISBN-10:0-262-11162-4). The challenges you have enumerated for high-speed compressible flows are very real, can be somewhat counter-intuitive, and are not always easy visualize. A good example is when an inlet experiences an “unstart”. Without variable geometry, the inlet cannot be “restarted” without decelerating to a lower speed such that the shock can be “swallowed”. Isentropic inlets have the best theoretical pressure recovery but, for a fixed geometry, have only one design-point operating condition. At other flight speeds, that are operating at off-design conditions. Variable geometry isentropic inlets have been experimentally evaluated, but none have gone into service to my knowledge. I’m glad you mentioned the fact that, for airbreathing engines, the net thrust developed is essentially the difference between the so-called gross thrust, (mdot_fuel + mdot_air) x V exhaust, and the ram drag, mdot_air x V flight, (I’m assuming exit pressure force is negligible, sorry for the ASC equations, also see http://www.grc.nasa.gov/WWW/K-12/airplane/turbab.html ). At high flight speeds, the net thrust can indeed be a small difference between two large numbers. And this fact has a practical consequence. Small disturbances, such as might result from atmospheric conditions or vehicle attitude, can result in the net thrust going to zero or negative. This puts a practical upper limit on airbreathing propulsion, a limitation not imposed on rocket propulsion. And this is another reason why you need some performance margin in your airbreathing propulsion system. I’d like to comment in particular about inlet precooling, and also about the so-called “Mass Injection Precooling for compressors” or MIPCC. A number of engine concepts over the years have suggested various forms of inlet pre-cooling. Pre-cooling is helpful in a number of important ways. One of the most significant is that it increases the density of the incoming air. For Turbocompressors, the compression efficiency goes up as the air density increases. Some of these concepts have proposed using heat exchangers within the inlet duct, and running cryogenic liquids through these exchangers. A physical limitation to this approach is that, based on the Reynold’s Analogy, the total pressure gains from Rayleigh cooling will always be less than the total pressure losses associated with friction, i..e. Fanno flow. Thus, although inlet precooling using heat exchangers does increase the air density, it still results in a net loss on total pressure increase. Spray cooling of the inlet flow, however, is a different story. As A.H. Shapiro described in his paper “The Aerothermopressor- A device for improving the performance of turbomachinery” (Trans. of the ASME, April, 1956) the injection of liquid droplets into an inlet flow can, depending on how its done, actually result in a net rise in total pressure within the inlet, hence the notion “aerothermopressor”. The use of spray injection for inlet pre-cooling was the basis for the paper “The Transition Engine: A Combined-Cycle Engine Concept for SSTO/Trans-atmospheric Vehicle Applications” (AIAA 95-2480), which I wrote and presented at the 1995 AIAA Joint Propulsion Conference. Although in principle, with a sufficiently high ratio of injectant flowrate-to-air flowrate any particular stagnation temperature can be maintained, at some point the injectant flow becomes the dominant flow through the inlet. In my paper, it seemed that around Mach 5 represented the upper limit where spray injection made sense. I should also point out that in my paper, the spray injection was used for maintaining a particular inlet temperature, and not for trying to take advantage of the “aerothermopressor” effect. The question that I find interesting is not “why are rockets a preferred acceleration engine?”, but “where would airbreathing engines EVER be a preferred acceleration engine?” Answering that question has the potential to be fruitful, even if the answer is “never”. However, I don’t’ think it is. I claim, not without basis, that airbreathing engines, and in particular the ATR, may have a role as an airbreathing component to suborbital, and possibly orbital launch vehicles. This of course, cannot be a blanket statement. Such a statement is loaded with all sorts of assumptions and caveats. As I stated in my own post, I don’t necessarily believe that airbreathers have been oversold, I just think that we have come to the conclusion that the effort that is required to get them to work isn’t worth the benefits they provide. The honest answer to the question of the role of airbreathers for space launch vehicles, is that we really don’t know whether there’s a role for them or not. But to say that they have no role is, in my opinion, shortsighted. One might end up missing out on a useful approach. If I didn’t think they didn’t offer some possible advantages, I wouldn’t be working on them, but I think it’s fair to say that I am in the minority. I do feel that there is an upper limit in terms of flight speed, beyond which airbreathing propulsion simply does not make any sense. In my opinion, that limit is probably around mach 5 or 6. Beyond that flight speed, the technical challenges become very difficult, and the benefits are rapidly fading away. Dr. John Whitehead of Lawrence Livermore National Laboratory (and of rocket piston-pump fame) provided an very interesting analysis on the utility of airbreathing engines in his 2007 AIAA JPC paper: “Airbreathing Acceleration Toward Earth Orbit”, AIAA 2007-5837. He concluded that the maximum flight for airbreathing propulsion is limited by the ratio of air capture area to vehicle drag area, and that for equal areas, this maximum flight speed is about Mach 6. Dr. Whitehead's background tends more towards rocket propulsion and he is by no means an airbreathing enthusiast, so I felt he provided a reasonable, objective assessment of airbreathing propulsion for launch vehicles. So what are we left with? Is there an airbreathing propulsion option that can take us from zero to mach 5 or 6? Does it have a sufficiently high T/W and Isp to justify its use? Can such a system be cost effective, and does it provide operational margin? Maybe there is such an engine, and more importantly, maybe there’s a vehicle configuration that can take advantage of these attributes. We’ll see. A great post, John. As you discuss in your post, inlets for airbreathing engines, especially for high speed flight, are indeed a central issue, and pose some of the most difficult technological challenges for efficient airbreather operation. The issues only get more difficult as the flight speeds increase.
Inlets play a central role in recovering total pressure from the free stream conditions, and as my old turbomachinery professor told us, “The total pressure through the engine (airbreather) is a fundamental performance parameter”, or words to that effect. If you can’t recover the total pressure, you can’t make thrust, no matter how hot you make the gas.
There are a number of different definitions or conventions that one can use to quantify the performance of the inlet. In modeling I’ve done, we often use simply an empirically derived pressure-recovery schedule, which specifies the ratio of recovered stagnation pressure to freestream stagnation pressure as a function of free stream mach number. An analytic function that is reasonable and robust is the use of the so-called kinetic energy efficiency, as given by Kerrebrock (Aircraft Engines and Gas Turbines, J.L. Kerrebrock. ISBN-10:0-262-11162-4).
The challenges you have enumerated for high-speed compressible flows are very real, can be somewhat counter-intuitive, and are not always easy visualize. A good example is when an inlet experiences an “unstart”. Without variable geometry, the inlet cannot be “restarted” without decelerating to a lower speed such that the shock can be “swallowed”.
Isentropic inlets have the best theoretical pressure recovery but, for a fixed geometry, have only one design-point operating condition. At other flight speeds, that are operating at off-design conditions. Variable geometry isentropic inlets have been experimentally evaluated, but none have gone into service to my knowledge.
I’m glad you mentioned the fact that, for airbreathing engines, the net thrust developed is essentially the difference between the so-called gross thrust, (mdot_fuel + mdot_air) x V exhaust, and the ram drag, mdot_air x V flight, (I’m assuming exit pressure force is negligible, sorry for the ASC equations, also see http://www.grc.nasa.gov/WWW/K-12/airplane/turbab.html ). At high flight speeds, the net thrust can indeed be a small difference between two large numbers. And this fact has a practical consequence. Small disturbances, such as might result from atmospheric conditions or vehicle attitude, can result in the net thrust going to zero or negative. This puts a practical upper limit on airbreathing propulsion, a limitation not imposed on rocket propulsion. And this is another reason why you need some performance margin in your airbreathing propulsion system.
I’d like to comment in particular about inlet precooling, and also about the so-called “Mass Injection Precooling for compressors” or MIPCC. A number of engine concepts over the years have suggested various forms of inlet pre-cooling. Pre-cooling is helpful in a number of important ways. One of the most significant is that it increases the density of the incoming air. For Turbocompressors, the compression efficiency goes up as the air density increases. Some of these concepts have proposed using heat exchangers within the inlet duct, and running cryogenic liquids through these exchangers. A physical limitation to this approach is that, based on the Reynold’s Analogy, the total pressure gains from Rayleigh cooling will always be less than the total pressure losses associated with friction, i..e. Fanno flow. Thus, although inlet precooling using heat exchangers does increase the air density, it still results in a net loss on total pressure increase. Spray cooling of the inlet flow, however, is a different story. As A.H. Shapiro described in his paper “The Aerothermopressor- A device for improving the performance of turbomachinery” (Trans. of the ASME, April, 1956) the injection of liquid droplets into an inlet flow can, depending on how its done, actually result in a net rise in total pressure within the inlet, hence the notion “aerothermopressor”.
The use of spray injection for inlet pre-cooling was the basis for the paper “The Transition Engine: A Combined-Cycle Engine Concept for SSTO/Trans-atmospheric Vehicle Applications” (AIAA 95-2480), which I wrote and presented at the 1995 AIAA Joint Propulsion Conference. Although in principle, with a sufficiently high ratio of injectant flowrate-to-air flowrate any particular stagnation temperature can be maintained, at some point the injectant flow becomes the dominant flow through the inlet. In my paper, it seemed that around Mach 5 represented the upper limit where spray injection made sense. I should also point out that in my paper, the spray injection was used for maintaining a particular inlet temperature, and not for trying to take advantage of the “aerothermopressor” effect.
The question that I find interesting is not “why are rockets a preferred acceleration engine?”, but “where would airbreathing engines EVER be a preferred acceleration engine?” Answering that question has the potential to be fruitful, even if the answer is “never”.
However, I don’t’ think it is. I claim, not without basis, that airbreathing engines, and in particular the ATR, may have a role as an airbreathing component to suborbital, and possibly orbital launch vehicles. This of course, cannot be a blanket statement. Such a statement is loaded with all sorts of assumptions and caveats.
As I stated in my own post, I don’t necessarily believe that airbreathers have been oversold, I just think that we have come to the conclusion that the effort that is required to get them to work isn’t worth the benefits they provide.
The honest answer to the question of the role of airbreathers for space launch vehicles, is that we really don’t know whether there’s a role for them or not. But to say that they have no role is, in my opinion, shortsighted. One might end up missing out on a useful approach. If I didn’t think they didn’t offer some possible advantages, I wouldn’t be working on them, but I think it’s fair to say that I am in the minority.
I do feel that there is an upper limit in terms of flight speed, beyond which airbreathing propulsion simply does not make any sense. In my opinion, that limit is probably around mach 5 or 6. Beyond that flight speed, the technical challenges become very difficult, and the benefits are rapidly fading away. Dr. John Whitehead of Lawrence Livermore National Laboratory (and of rocket piston-pump fame) provided an very interesting analysis on the utility of airbreathing engines in his 2007 AIAA JPC paper: “Airbreathing Acceleration Toward Earth Orbit”, AIAA 2007-5837. He concluded that the maximum flight for airbreathing propulsion is limited by the ratio of air capture area to vehicle drag area, and that for equal areas, this maximum flight speed is about Mach 6. Dr. Whitehead’s background tends more towards rocket propulsion and he is by no means an airbreathing enthusiast, so I felt he provided a reasonable, objective assessment of airbreathing propulsion for launch vehicles.
So what are we left with? Is there an airbreathing propulsion option that can take us from zero to mach 5 or 6? Does it have a sufficiently high T/W and Isp to justify its use? Can such a system be cost effective, and does it provide operational margin? Maybe there is such an engine, and more importantly, maybe there’s a vehicle configuration that can take advantage of these attributes. We’ll see.

]]> By: Randy Campbell http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-5250 Randy Campbell Thu, 23 Jul 2009 14:21:05 +0000 http://selenianboondocks.com/?p=1099#comment-5250 John H. wrote: >I looked at the link before but just couldn’t see enough detail. >Is there a good paper on the concept? Several actually, though mostly they consist of Thesis written using the ASTROX programs for parametric studies and comparisions of Air-Breathing and Rocket launch vehicles. If you can't link to these or see them let me know. I think I have copies I can email. http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA451531 (Click the "Handle/Proxy" link to get to the paper or try this url) http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA451531&Location=U2&doc=GetTRDoc.pdf This one you probably can't get but: https://www.afresearch.org/skins/rims/q_mod_be0e99f3-fc56-4ccb-8dfe-670c0822a153/q_act_downloadpaper/q_obj_2c119f70-791d-4fd0-aadd-05908765ac94/display.aspx?rs=enginespage http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA451531&Location=U2&doc=GetTRDoc.pdf The appendix sections on this one provide a lot of interesting information not only on the Inward-Turning design but others as well: http://www.docstoc.com/docs/995500/Reusable-Military-Launch-Systems-(RMLS) The original document can be found here: http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA477059&Location=U2&doc=GetTRDoc.pdf article on ASTROX and U-of-M work: http://www.mtech.umd.edu/news/press_releases/mips_astrox.html If these don't help let me know and I'll see what else I can find Randy John H. wrote:
>I looked at the link before but just couldn’t see enough detail.
>Is there a good paper on the concept?

Several actually, though mostly they consist of Thesis written using the ASTROX programs for parametric studies and comparisions of Air-Breathing and Rocket launch vehicles. If you can’t link to these or see them let me know. I think I have copies I can email.
http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA451531
(Click the “Handle/Proxy” link to get to the paper or try this url)
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA451531&Location=U2&doc=GetTRDoc.pdf

This one you probably can’t get but:
https://www.afresearch.org/skins/rims/q_mod_be0e99f3-fc56-4ccb-8dfe-670c0822a153/q_act_downloadpaper/q_obj_2c119f70-791d-4fd0-aadd-05908765ac94/display.aspx?rs=enginespage

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA451531&Location=U2&doc=GetTRDoc.pdf

The appendix sections on this one provide a lot of interesting information not only on the Inward-Turning design but others as well:
http://www.docstoc.com/docs/995500/Reusable-Military-Launch-Systems-(RMLS)
The original document can be found here:
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA477059&Location=U2&doc=GetTRDoc.pdf

article on ASTROX and U-of-M work:
http://www.mtech.umd.edu/news/press_releases/mips_astrox.html

If these don’t help let me know and I’ll see what else I can find

Randy

]]> By: john hare http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-5248 john hare Thu, 23 Jul 2009 00:46:07 +0000 http://selenianboondocks.com/?p=1099#comment-5248 I looked at the link before but just couldn't see enough detail. Is there a good paper on the concept? I looked at the link before but just couldn’t see enough detail. Is there a good paper on the concept?

]]> By: Randy Campbell http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-5247 Randy Campbell Wed, 22 Jul 2009 21:15:56 +0000 http://selenianboondocks.com/?p=1099#comment-5247 John H. wrote: >I have the inward turning in my dead tree references. It is a >favorite for missle use if we are talking about the same inlet. >I spent a few bucks on the two textbooks available from AIAA >on the subject. English authors have me wanting to call them >intakes though. We "may" be talking about the same inlets though that's a point the literature and web information can be confusing on. It's one of the reasons I included the link to the ASTROX company: http://www.astrox.com/ More specifically I should have included a link to their airbreathers image page: http://www.astrox.com/AirBreathers.aspx and the HySide brochure page (page 1) http://www.astrox.com/SIDEBrochure.pdf As you'll note the "inward-turning" design in the illustrations looks similar to a "C" on its side (with the opening down) and it IS open all most all the way back to the combustor. It opens again directly after the combustor and remains so all the way to the rear of the vehicle. Though most 'inward-turning' inlets shown on vehicles show them fully enclosed from inlet to exhaust (as depicted in most of the Falcon, or HTV-3 images) this "new" style has emerged within the past 4 or so years to be the style of choice in most studies due to lowered mechanical complexity, (it does not require adjustable ramps as the "slot" seems to allow for self adjusment of inlet air at the desired Mach) less heating as the slot automatically 'dumps' excess air without needing mechanical dump vents as well as because the inlet is more streamlined and the overall vehicle aerodynamics are far better than either the "outward" or 2D installations previously studied. Though most of the material I've read on this inlet are predicated on the use of Rocket Based Combined Cycle engine (RBCC) due to the percived mass-penalty of turbine engines I believe that coupled with the ATR this design could achieve some serious mass saveings over a 'standard' Turbine Based Combined Cycle engine system. Randy John H. wrote:
>I have the inward turning in my dead tree references. It is a
>favorite for missle use if we are talking about the same inlet.
>I spent a few bucks on the two textbooks available from AIAA
>on the subject. English authors have me wanting to call them
>intakes though.

We “may” be talking about the same inlets though that’s a point the literature and web information can be confusing on. It’s one of the reasons I included the link to the ASTROX company:
http://www.astrox.com/

More specifically I should have included a link to their airbreathers image page:
http://www.astrox.com/AirBreathers.aspx
and the HySide brochure page (page 1)
http://www.astrox.com/SIDEBrochure.pdf

As you’ll note the “inward-turning” design in the illustrations looks similar to a “C” on its side (with the opening down) and it IS open all most all the way back to the combustor. It opens again directly after the combustor and remains so all the way to the rear of the vehicle. Though most ‘inward-turning’ inlets shown on vehicles show them fully enclosed from inlet to exhaust (as depicted in most of the Falcon, or HTV-3 images) this “new” style has emerged within the past 4 or so years to be the style of choice in most studies due to lowered mechanical complexity, (it does not require adjustable ramps as the “slot” seems to allow for self adjusment of inlet air at the desired Mach) less heating as the slot automatically ‘dumps’ excess air without needing mechanical dump vents as well as because the inlet is more streamlined and the overall vehicle aerodynamics are far better than either the “outward” or 2D installations previously studied.

Though most of the material I’ve read on this inlet are predicated on the use of Rocket Based Combined Cycle engine (RBCC) due to the percived mass-penalty of turbine engines I believe that coupled with the ATR this design could achieve some serious mass saveings over a ‘standard’ Turbine Based Combined Cycle engine system.

Randy

]]> By: John Bossard http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-5246 John Bossard Wed, 22 Jul 2009 19:49:38 +0000 http://selenianboondocks.com/?p=1099#comment-5246 John H: You've provided a very good post here. Thank you also for the "tip o' the hat", you do me great honor, sir. I will be providing some additional comments to this post, but I'm a bit behind right now. I'll try to provide some comments within 24 hours. John H:
You’ve provided a very good post here. Thank you also for the “tip o’ the hat”, you do me great honor, sir.
I will be providing some additional comments to this post, but I’m a bit behind right now. I’ll try to provide some comments within 24 hours.

]]> By: john hare http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-5230 john hare Mon, 20 Jul 2009 08:36:40 +0000 http://selenianboondocks.com/?p=1099#comment-5230 Randy, I have the inward turning in my dead tree references. It is a favorite for missle use if we are talking about the same inlet. I spent a few bucks on the two textbooks available from AIAA on the subject. English authors have me wanting to call them intakes though. Mike, From a cost standpoint, the rocket vehicle will win if there is no cruise component to the flight. As will be pointed out again here by somebody, LOX is cheap. Air is free, but the convenience store charges more for it than gasoline. The value of an ABE is in flexibility given by a cruise phase such as fly back, fly forward, and loiter time if required. Randy,
I have the inward turning in my dead tree references. It is a favorite for missle use if we are talking about the same inlet. I spent a few bucks on the two textbooks available from AIAA on the subject. English authors have me wanting to call them intakes though.

Mike,
From a cost standpoint, the rocket vehicle will win if there is no cruise component to the flight. As will be pointed out again here by somebody, LOX is cheap. Air is free, but the convenience store charges more for it than gasoline.

The value of an ABE is in flexibility given by a cruise phase such as fly back, fly forward, and loiter time if required.

]]> By: Randy Campbell http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-5227 Randy Campbell Mon, 20 Jul 2009 05:45:32 +0000 http://selenianboondocks.com/?p=1099#comment-5227 John H: There is a newer-type inlet known as the "Inward-Turning" inlet, some illustrations of which can be found here" http://www.astrox.com/SIDEBrochure.pdf A patent can be found here (I have a free account at freepatentsonline, I will follow with the patent number and title so others can use thier favorite patent look-up engine :) http://www.freepatentsonline.com/6164596.pdf Refernces for search are: US Patent 6164596 - Designs of and methodology for inward or outward, and partially inward or outward turning flow hypersonic air-breathing and rocket-based-combined-cycle vehicles Randy John H:
There is a newer-type inlet known as the “Inward-Turning” inlet, some illustrations of which can be found here”
http://www.astrox.com/SIDEBrochure.pdf

A patent can be found here (I have a free account at freepatentsonline, I will follow with the patent number and title so others can use thier favorite patent look-up engine :)
http://www.freepatentsonline.com/6164596.pdf

Refernces for search are: US Patent 6164596 – Designs of and methodology for inward or outward, and partially inward or outward turning flow hypersonic air-breathing and rocket-based-combined-cycle vehicles

Randy

]]> By: Mike Lorrey http://selenianboondocks.com/2009/07/feeding-the-turborocket/comment-page-1/#comment-5226 Mike Lorrey Mon, 20 Jul 2009 01:19:17 +0000 http://selenianboondocks.com/?p=1099#comment-5226 This is one of those situations where an insistence on perfect becomes the enemy of the good enough. Keep in mind that, for instance, the Falcon 1 first stage separates at under mach 6. Most rockets burn 2/3 to 3/4 of their propellant before they reach mach 6, most of the mass of which is LOX, which is of course eliminated from the mass budget of an air breather for that phase of flight. So really, an air breathing first stage makes a lot of sense not only on a fuel mass budgetary standpoint, but by making it an air breather, you are already on your way to making it a recoverable, reusable first stage, with all the potential cost benefits that come from that too. A mach 6 first stage would generally be a chassis cross-applicable to other HST needs. The rocket propelled second stage may or may not be reusable, generally depending on whether the payload is mass or men. This is one of those situations where an insistence on perfect becomes the enemy of the good enough.

Keep in mind that, for instance, the Falcon 1 first stage separates at under mach 6. Most rockets burn 2/3 to 3/4 of their propellant before they reach mach 6, most of the mass of which is LOX, which is of course eliminated from the mass budget of an air breather for that phase of flight.

So really, an air breathing first stage makes a lot of sense not only on a fuel mass budgetary standpoint, but by making it an air breather, you are already on your way to making it a recoverable, reusable first stage, with all the potential cost benefits that come from that too.

A mach 6 first stage would generally be a chassis cross-applicable to other HST needs. The rocket propelled second stage may or may not be reusable, generally depending on whether the payload is mass or men.

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