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#26 2006-02-01 20:57:37

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,838

Re: hypersonic

Which makes the Hypersonic bomber a quick attack vehicle with no noticeable build up of force indicating the chance for attack and unless you have advance mission detection systems that means you will not know that it is coming.....

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#27 2006-02-01 21:06:37

John Creighton
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From: Nova Scotia, Canada
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Posts: 2,401
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Re: hypersonic

Lets forget for a sec weather a hypersonic bomber is needed today. Consider what happens if another nation gets one first. Can an aircraft carrier possibly defend against a hypersonic bomber? Another thought is for city attacks, what happens if the  fleches approaches a city at a nearly horizontal angle. How many buildings can one fleche go though?


Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]

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#28 2006-02-01 22:49:34

Austin Stanley
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From: Texarkana, TX
Registered: 2002-03-18
Posts: 519
Website

Re: hypersonic

Lets forget for a sec weather a hypersonic bomber is needed today. Consider what happens if another nation gets one first. Can an aircraft carrier possibly defend against a hypersonic bomber? Another thought is for city attacks, what happens if the  fleches approaches a city at a nearly horizontal angle. How many buildings can one fleche go though?

This is a pretty good point.  It would be pretty difficult to impossible for a Carrier to defend against an orbital attack.  And a single KE munition could do a lot of damage to such a Carrier.  However, hitting any mobile target, even one as big as a Carrier would be quite a trick.  Even if it was just crusing around at a moderate pace, the thing could be tens of kilometers (if not farther) from where it was when you launched your mission.  You would have to find it again, and then direct your incoming hyper-sonic warhead to hit the now rapidly evading target.  It would be very difficult.

As for KE weapons versus cities, they are rather useless.  If you just want to carpet bomb indiscrimanetly.  A cruise missle loaded with bomblets, or a conventional strategic bomber could achive more destruction.  But in fact, a B2 loaded with JDAMs could achive more destruction, and dole it out with devestating precision.  Of course, with the political consiquences with an indescrimante bombing campaign, you might as well just nuke the city.

KE fragmination weapons might have some use against armor formations, but again cruise missles or fighters/bombers loaded with bombets can do the same thing.  And will probably be more effective as the bomblets from them can actively home in on their targets, while the KE would be more like a scatter shot.

Which makes the Hypersonic bomber a quick attack vehicle with no noticeable build up of force indicating the chance for attack and unless you have advance mission detection systems that means you will not know that it is coming.....

It's as detectable as an ICBM or any other orbital launch, IE the Chinese or Russians would see it coming.  If you want to catch one of the major powers of guard, a cruise missle or B2 strike has a better chance.  Now the Iranians wouldn't see it coming, but they wouldn't see a B2 or Cruise Missle strike either, at least not untill it was to late.


He who refuses to do arithmetic is doomed to talk nonsense.

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#29 2006-02-02 09:16:09

PurduesUSAFguy
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From: Purdue University
Registered: 2004-04-04
Posts: 237

Re: hypersonic

It's as detectable as an ICBM or any other orbital launch, IE the Chinese or Russians would see it coming. If you want to catch one of the major powers of guard, a cruise missle or B2 strike has a better chance. Now the Iranians wouldn't see it coming, but they wouldn't see a B2 or Cruise Missle strike either, at least not untill it was to late.

Actually I'd have to disagree with you their. Maybe the inital CAV launcher, which would basically be a cheap mass produced ICBM first stage anyways would be detectable by IR satilites,  but since it's a hypersonic gliding target rather then a ballistic target it really isn't in the same ballpark as a MIRV.  Especially if incorperate some basic low level stealthing features. 

Now once we have the reusable hypersonic launcher, which would presumably be at least partially air breathing, then all bets are off as far as thermal bloom detection.

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#30 2006-02-02 15:04:56

Dook
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From: USA
Registered: 2004-01-09
Posts: 1,409

Re: hypersonic

I have an even better idea: leave Iran alone. Russia offered to produce fuel rods for Iran so their nuclear power plant doesn't require uranium enrichment technology within their borders. Accept that. But this thread is about hypersonic; I think the point has been made that you don't need a hypersonic suborbital bomber to take out a third world country.

Leave Iran alone, as if all the big boys in the yard are picking on the poor little arab children. 

Hasn't the world stood by enough, too much, in the past? 

You think the war in Iraq is not worth it because other people's freedom is not worth anything to you.  It's a give or take thing, you'll take it if it's provided but you could live under the regime of the old USSR just the same.

Iran is a threat, big time.  Only a few years ago they sent an entire ship full of arms to Gaza only the Israeli's intercepted it.  Their elected leader proclaimed the destruction of Israel. 

Iran is a major oil exporter and certainly has enough to supply it's own power needs but somehow it needs nuclear energy?  Yeah and Saudi Arabia needs more sand.

How many nuclear warheads to destroy Isreal?  Four?  Iran wouldn't think twice about giving a nuke to Hamas and letting them drive it into downtown Tel Aviv.

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#31 2006-02-02 15:58:49

Commodore
Member
From: Upstate NY, USA
Registered: 2004-07-25
Posts: 1,021

Re: hypersonic

I have an even better idea: leave Iran alone. Russia offered to produce fuel rods for Iran so their nuclear power plant doesn't require uranium enrichment technology within their borders. Accept that.

We have. Iran has not. Thus the problem.


"Yes, I was going to give this astronaut selection my best shot, I was determined when the NASA proctologist looked up my ass, he would see pipes so dazzling he would ask the nurse to get his sunglasses."
---Shuttle Astronaut Mike Mullane

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#32 2006-02-02 17:59:29

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,803
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Re: hypersonic

Iraq was not part of the al Qaeda attack. There are more terrorists in Iraq now than before the war. Even George W. Bush admitted that if US troops were to withdraw now, the Iraqi government would fall. That is not a government of the people of Iraq. The current Iraqi government is no more legitimate than the occupation government of France in Vichy during World War 2. Establishing "no fly zones" in Iraq was a mistake, invading was worse. Even the current US government now admits invading was a bad idea. So you want to repeat that mistake in Iran? A shipment of arms to the government of Palestine was not criminal; intercepting it was an act of war. I don't defend the actions of Palestinians, but the actions of Israel are just as bad. Two wrongs do not make a right. Failure to honour the treaty that created Palestine and occupying this new nation was a serious offence. Israel has dozens of nukes, Iran wants one or two. None of them can be used, they're just a waste of money. Stop obsessing over dominance. Anyone who tries to dominate is the opponent and enemy of freedom and liberty. Don't be that enemy. The bottom line is freedom means YOU don't tell them what to do in THEIR country. Stop turning the United States of American from a free and democratic nation into Stalinism.

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#33 2006-02-02 19:59:48

GCNRevenger
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From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: hypersonic

Iraq was not part of the al Qaeda attack. There are more terrorists in Iraq now than before the war. Even George W. Bush admitted that if US troops were to withdraw now, the Iraqi government would fall. That is not a government of the people of Iraq. The current Iraqi government is no more legitimate than the occupation government of France in Vichy during World War 2. Establishing "no fly zones" in Iraq was a mistake, invading was worse. Even the current US government now admits invading was a bad idea. So you want to repeat that mistake in Iran? A shipment of arms to the government of Palestine was not criminal; intercepting it was an act of war. I don't defend the actions of Palestinians, but the actions of Israel are just as bad. Two wrongs do not make a right. Failure to honour the treaty that created Palestine and occupying this new nation was a serious offence. Israel has dozens of nukes, Iran wants one or two. None of them can be used, they're just a waste of money. Stop obsessing over dominance. Anyone who tries to dominate is the opponent and enemy of freedom and liberty. Don't be that enemy. The bottom line is freedom means YOU don't tell them what to do in THEIR country. Stop turning the United States of American from a free and democratic nation into Stalinism.

Nobody but a terrorist murderer or a symphathizer for them could possibly believe that "actions of the Israelis are just as bad;" if you really truely believe this, that mowing down a car load of todlers or shooting rockets at a school or detonating a suicide bomb on a goddamn school bus is just as bad as Israeli roadblocks and incursions to arrest known terrorist, you are an immoral piece of loser trash, Robert.

"(the) shipment of arms to the [i]government of Palestine was not criminal; intercepting it was an act of war."[/i]

There never has been, nor is there now, and not likly to ever be a such thing as a "government" of Palestine. Before Arafat helped come up with the name fifty years ago, there wasn't even a such thing as a Palestinian! And if it were such a thing, then the ongoing and unending cross-border artillery and infiltration murder attacks by terrorist sactioned by the ruling party of the "Palestinian" Authority is more then enough of a cause for total war against the "Palestinians."

And Israel was just supposed to let them import enough fire power to equip an army? What kind of f**king idiot are you!?

"Failure to honour the treaty that created Palestine and occupying this new nation was a serious offence."

And then the "Palestinians" allied with Arab neighbors tried unsucessfully to COMMIT GENOCIDE, by their own admission(!!!), not once but TWICE. Whatever claim they formally had is worthless.

"Israel has dozens of nukes, Iran wants one or two"

Has Israel proclaimed that, paraphrasing Egyptian radio broadcasts before the Six Day War, "that no peace with the zionist entity was possible, and we will drive all the Jews into the sea?" Or the modern day president or Iran, just these past few months, has openly called for the obliteration of the state of Israel?

Thats a rhetorical question. And Iran "only wants one or two..." WTF??? Iran only NEEDS "one or two" to obliterate Israel once and for all. The Iranian president is insane, and insane people are not guided by reason, and Israel nor the US can afford to trust a crazy madman with the bomb.

"Anyone who tries to dominate is the opponent and enemy of freedom and liberty. Don't be that enemy."

Even if the opponet plots your destruction? As JFK said, or something to the effect, that no nation can any longer afford to only react to attack in today's world with WMDs. That is still true today, and of all the countries in the world, most true for Israel. The government of Iran has offically and publicly called for Israel to be "wiped off the map," and so they cannot be trusted with nuclear weapons. Period.

"Even the current US government now admits invading was a bad idea"

There are plenty of liberals in the government, but if by "current US government" doesn't include a majority of congressmen in both houses or opinion of President Bush himself, then the above is a flat lie.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#34 2006-02-02 21:57:46

Austin Stanley
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From: Texarkana, TX
Registered: 2002-03-18
Posts: 519
Website

Re: hypersonic

I'm more intrested in "Realpolitik," and I think some disengagment from the Middle East, and Israel especialy is necessary.  I agree that there is some chance that if Iran was to gain access to Nuclear weapons, that they would use them against Israel.  But more likely they would hold them in reserve, against possible Israel nuclear attack.  Looking at it from Irans position, they have no real reason to believe that the Israels won't use nuclear weapons upon them at some point in the future, unless the develope a credible counterthreat.  We may see this point of view as absurde, but the Iranians (for some admitidly good reasons) probably belive this very strongly, and it is highly unlikely that we can convince them that this is otherwise.

But what does all this mean to the US?  What should our position be?  I think we should disenage and let other parties sort the mess out.  If Iran and Israel want to trade nukes or go to war again against each other, I say let them.  Israel has not been the best ally to the US (they carrier out lots of spying against us), despite the incredibly massive amount of support the US gives them in return.  And our support for Israel does nothing but antagonise the other middle eastern nations.

Put another way, some 60 years ago Israel took over a section of the Middle East and made it their homeland.  A large portion of the people in that part of the world are very unhappy about this.  Who is right and wrong in this situation is now irrelevent, Israel must find a way to come to terms with these people.  Be it by further fortification and warfare, or by other more peacefull means.  Whatever it may be, I think experince has shown that the US's intervention has not been productive in solving this problem, and has only aggrevated our problems with the other people of the Middle East.  It's time to admit defeat, and let the intrested parties find there own ways of sorting it out.

This may not be very humane, but it is Realpolitik.  The US's intrest are truly not supported by supporting either party, since it can only come at the price of angering the other.  So we should take a more neutral stance towards both groups, and let them settle their own problems.


He who refuses to do arithmetic is doomed to talk nonsense.

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#35 2006-02-02 21:59:14

John Creighton
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From: Nova Scotia, Canada
Registered: 2001-09-04
Posts: 2,401
Website

Re: hypersonic

I don't think this forum says "free chat".  roll


Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]

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#36 2006-02-02 22:47:34

Austin Stanley
Member
From: Texarkana, TX
Registered: 2002-03-18
Posts: 519
Website

Re: hypersonic

Your right, sorry for going off topic.

Actually I'd have to disagree with you their. Maybe the inital CAV launcher, which would basically be a cheap mass produced ICBM first stage anyways would be detectable by IR satilites, but since it's a hypersonic gliding target rather then a ballistic target it really isn't in the same ballpark as a MIRV. Especially if incorperate some basic low level stealthing features.

Now once we have the reusable hypersonic launcher, which would presumably be at least partially air breathing, then all bets are off as far as thermal bloom detection.

Well the terminal phase will always be easily detectable, but at that point it is general to late to do anything.

However, I do not think an air-breathing scramjet launcher realy changes anything during the boost phase.  An air-breathing launcher still has to expend just as much energy to get into orbit as a convetional one does.  Just it collects most of it's oxidier from the atmosphere on the way up.  It's engines have to be just as large and put out just as much heat as conventional engines do.  In fact, they are probably even more detectable then conventional ICBMs, since the air-breathing launchers larger payload demands more energy to be expended during the assent phase.  So if anything it will be MORE detectable via thermal ploom then an ICBM.

I'm not sure to what extent the Russians/Chinese rely upon ground based radars for early warning, but without some tricky to implement stealth technology, these will still be effective as well.


He who refuses to do arithmetic is doomed to talk nonsense.

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#37 2006-02-03 14:08:15

publiusr
Banned
From: Alabama
Registered: 2005-02-24
Posts: 682

Re: hypersonic

Let Israel strike Iran and we stay out. If we fight Iran and stay in Iraq, and South Korea--kiss NASA goodbye. The best way to get stung is to stir up a nest.

There is nothing to say that China can't supply a nuke to an independant terror group with no link to Iran. Frankly I would have spent the Iraq war money on Russian oil development and ANWR drilling--maybe even a Bering Strait Bridge to reduce dependance on Muslim oil. That done, I would sign a pact with Putin that if any WMD were exploded on either US or Russian shores, that the combined nuclear arsenal of BOTH US and Russia would be unleashed in something like the Samson option. It would be a good bluff.

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#38 2006-02-03 16:37:55

Rxke
Member
From: Belgium
Registered: 2003-11-03
Posts: 3,669

Re: hypersonic

I don't think this forum says "free chat".  roll

Indeed it does not.

Please.

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#39 2006-02-04 08:24:54

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: hypersonic

I don't think this forum says "free chat".  roll

Indeed it does not.

Please.

Sorry to the other members, but naked and unappologetic anti-semitism makes me furious.


[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

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#40 2006-02-04 09:50:32

bobunf
Member
From: Phoenix, AZ
Registered: 2005-11-21
Posts: 223

Re: hypersonic

RobertDyck wrote:

“Anyone who tries to dominate is the opponent and enemy of freedom and liberty”

Isn’t “freedom and liberty” redundant, or am I missing some difference?

“freedom means YOU don't tell them what to do in THEIR country”

Robert, taken together these too phrases seem to me to endorse a most immoral and unwise position, which I’m sure you don’t advocate. 

History abounds with examples of nations interfering in other nation’s affairs (i.e., telling other people what to do in their own country) with results that I think nearly everyone would consider admirable, justified and even heroic.  For instance,

Was it wrong of the British to ban the slave trade in 1807?  And to cajole, threaten and even bribe other nations (Spain and Portugal) and groups to ban or refran from the slave trade? To police the ban by stopping, boarding, inspecting, and seizing the slave ships of other nations?  To effect armed incursions of other countries, destroying slaving facilities, and freeing thousands of slaves?  For no benefit, and considerable cost to the British? A policy entirely innocent of benefiting the national interest?  Was all of this opposing freedom?  Or was this a set of policies and series of acts among the perfectly virtuous pages in the history of nations?

And there are, perhaps, an even larger series of lamentable lack of virtue in human history, of so many times when other nations have failed to tell people of other countries what to do in their own country; have failed to act with force and violence.  For instance,

Was it right for all of the other countries in the world to leave Rwanda alone only twelve years ago?  When an average of 8,000 people a day were killed for being of the wrong tribe (or sympathizing with) for one hundred days.  Was it right for the first world nations, other African nations, and the UN to leave Rwanda alone?

I think principles of the behavior of nations have to be much more nuanced than simply, Hands Off. I expect that you, too, agree.

Bob

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#41 2006-02-04 11:13:08

Rxke
Member
From: Belgium
Registered: 2003-11-03
Posts: 3,669

Re: hypersonic

Hypersonic. Next post better be on-topic.

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#42 2006-02-04 18:39:23

Grypd
Member
From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,879

Re: hypersonic

Hypersonic. Next post better be on-topic.

In some ways the idea behind the need for a hypersonic bomber is political so digressing into politics and the reason why such a bomber is needed makes sense.

A hypersonic strike bomber and this is what this plane would be is not for regular attacks no this is for hit them when they dont expect anywhere on the world quickly. A Bomber is a direct result of the apparent need it is built for. The hypersonic bomber is not for major attacks but for quick drops of small amounts of precision guided weapons. It would also allow the USA to field anti satelite weapons anywhere and this has interest in a world where a lot more countries are fielding rockets capable of launching satelites and significantly orbiting weapons into space. There is also the possibility that the USA will need in the future a capability to stop something from going down. This could be a future Scud launch or a need to get to the leader of a dangerous terror cell or even in times of war to be able to fly so quickly in and strike at the most important targets that regular air defences would defeat the f117 and Stealth bomber.

What ever happens the Hypersonic Bomber will be a means of directing force quickly and effectively anywhere in the world. It is this capability and the usefelness that this gives the US military and Political leaders that makes it likely it will be supported. Again it is politics but then so what is war but politics with guns.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

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#43 2006-02-04 20:43:39

reddragon
Banned
From: Earth
Registered: 2005-01-24
Posts: 193

Re: hypersonic

I am glad that someone is finally working on a scramjet, but it bugs me that it's the military. If NASA wanted to do this, people would say it was too expensive or otherwise not worth it. But when the airforce says they need it to keep us safe (a claim that is usually successful without even basic justification), noone complains. The actual military use of this thing seems doubtful, as others have already said. Sure it could be useful, but it has limited applications, most of which can be achieved with other things, and is only necessary against an adversary at a tech level similar to our own. The benefits of civilian use, on the other hand, could be much greater. Easier access to space is the most obvios and most important. Even if this vehicle couldn't put a payload into orbit, it's certainly on the right track to do so. Furthermore, it might be useful for more traditional aviation uses, such as passenger or cargo delivery, if really fast delivery was necessary or was desired by someone who could pay for it.

If the army does build this thing, I certainly hope they don't cover it up. To me it seems inexcusable that the military will spend taxpayer money to build something, and then not let us know it exists, even when it could have civilian uses. Sure the military needs to keep some secrets, but it keeps a lot more than it needs to I think. It would be horrible if the air-force was flying these things around, without even being in a war where they would be needed, and NASA was still flying on disposable rockets. Any technology developed and any knowledge gained should be shared in full with NASA, and vehicles using the tech should be built for space use. We need a scramjet to get to space a heck of a lot more than we need it for "defense." Yet  it's always the military who get to spend ridiculous sums on things that might potentially be useful to someone, somewhere, sometime in the hypothetical future.


Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun.

             -The Hitchhiker's Guide to the Galaxy
              by Douglas Adams

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#44 2006-02-05 00:15:59

Commodore
Member
From: Upstate NY, USA
Registered: 2004-07-25
Posts: 1,021

Re: hypersonic

The military always gets stuff first. As far as I'm conserned I'd be glad to let the Air Force pay for it. NASA can buy it off the shelf later.


"Yes, I was going to give this astronaut selection my best shot, I was determined when the NASA proctologist looked up my ass, he would see pipes so dazzling he would ask the nurse to get his sunglasses."
---Shuttle Astronaut Mike Mullane

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#45 2006-02-05 20:39:37

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,838

Re: hypersonic

Hypersonic. Next post better be on-topic.

Thanks...

I am glad that you have monitoring the comments, I had hoped that it would not continue but would rather start talking about the specifics of the ship itself and what would be required to make such a ship happen.

We know that speeds of Mach 15 plus and reentry speed heat disappation are just some of the work required but there is a whole lot more....

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#46 2006-02-05 23:30:39

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,803
Website

Re: hypersonic

One issue is shock wave compression. This produces extreme heating and specified angle from the leading edge. The X-43A uses the bow to produce the shockwave, which is directed into the SCRAM jet inlet. At subsonic speed the shockwave doesn't form. At supersonic speed (mach 1-5) the shockwave goes around the inlet. At high hypersonic speed (mach 10-25) the shockwave is too narrow, it doesn't reach the bottom of the engine. If the shockwave doesn't fill the engine, combustion results in gas expansion to within the engine rather than thrust.

Personally I think the solution for varying hypersonic speeds is similar to the engine for SR-71 Blackbird. Traditional supersonic engines slow airflow to subsonic speed, but rely upon the supersonic shockwave to hold pressure in the front. That requires the shockwave fill the intake. To ensure the shockwave hits intake walls before the turbine blades, it has a cone that can be moved forward for faster flight, or back into the engine for slower flight. The shockwave starts at the tip of the cone but it's angle depends on speed. We need something like that for a SCRAM jet. This means we cannot rely on the body shape alone. Perhaps an intake at the front of the aircraft with a central cone or central flat blade. Or perhaps simply a flat nose like X-43A but designed to slide forward for faster flight, and back into the aircraft for slower flight. A sliding nose blade would slide similar to the flaps of modern airliner wings. Ever notice how the flaps slide out making the wing wider before the flaps angle down?

Another issue is air surface heating. X-43A had a titanium skin to endure mach 10 heating. Inconel can endure slightly higher temperatures, but the heatshield of Shuttle can endure much more than that. Reinforced Carbon-Carbon (RCC) can endure 3,000°F; it's used on the Shuttle where temperatures can exceed 2,300°F. SCRAM jet leading edges can also achieve 3,000°F, which shouldn't come as a surprise considering were talking about the same speed range. Higher than mach 10 requires RCC nose and engine intake leading edges.

The razor thin lifting body of X-43A is not practical for a spacecraft. It has too much surface that must be protected by heatshield during atmospheric entry, and not enough interior volume for fuel and cargo. The HL-20 body shape is much more practical. The HL-20 was reverse engineered from BOR-4 then slightly improved. However, the BOR series was unmanned scale models for Spiral. The manned prototype for Spiral and plans for the complete vehicle had the two outer fins swing into horizontal position to form wings for landing. The flair prior to landing is the only time you need wings, a lifting body is enough otherwise. Use the HL-20 body shape with big, fat nose intake like the A-7 Corsair II.

Note: a computer model using computational fluid dynamics for the HL-20 indicated it didn't need RCC on the leading edges of its wings. Just the nose required RCC, the wings could use HRSI.

Quoting from Encyclopedia Astronautica "Wind tunnel tests showed configuration directional stability at all speeds from subsonic to Mach 20, trimmed to maximum L/D with 10 degree elevon deflections in subsonic range, with no control deflection at Mach 0.6 to 0.9, at 3 degree angle of attack in transonic range, and then again with no deflection from Mach 2.0 to Mach 20."

Another issue is ensure fuel/air mixing and combustion before it goes out the back and of the engine. At mach 10 air passed through a 10 metre long engine in 1 millisecond. Hydrogen can burn that fast, but faster speed may require a longer engine. A nose intake like A-7 permits an engine long enough to combust fuel at higher than mach 10 speed. It may require multiple fuel injectors; faster flight using injectors closer to the nose, slower flight using aft injectors.

An LH2 fuelled SCRAM jet will still require mach 4 or higher to work. It's interesting that X-43A required mach 5 but engine design work will permit mach 4 operation. A couple articles from the Journal of Propulsion and Power have papers from Air Force contractors working on supersonic combustion turbine engines that work at airspeed up to mach 6 using jet fuel. Normal jet fuel is based on kerosene.

Put all these things together and you get an aircraft that can take off and land on its own wheels, has two engines with a separate fuel tank for each, but can reach mach 20 in the stratosphere. The fat lifting body can still carry payload.

To go into space you then need the ability for the SCRAM jet to transition to LOX/LH2 rocket. That makes it an RBCC but without subsonic combustion RAM jet capability. Eliminating subsonic operation should make it simpler. If a cylindrical engine is used with intake similar to A-7 then the exhaust could be a de Laval nozzle like a rocket engine. But the exhaust from a subsonic combustion RAM jet is a de Laval nozzle, a SCRAM jet is a straight tube. Hmm. Perhaps the rocket combustion chamber must be separate with the throat feeding into the SCRAM jet engine. Could the SCRAM jet be configured to be the divergent bell of a de Laval nozzle? How would that integrate with low pressure hypersonic intake air for the transition? During the transition you would have to gradually increase intake compression, and combustion would require intake air. No, fuel injection would have to be in the main engine. It would require a "throat" that can be constricted for the SCRAM/rocket transition. In fact, it would require two throats: intake to combustion chamber, and combustion to divergent nozzle.

This sounds like a cylindrical engine is required, not a rectangle. And the throats must use the same technology as the thrust vectoring nozzle of a fighter jet engine. The intake throat may require a plug for the final conversion to rocket engine.

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#47 2006-02-08 17:24:34

reddragon
Banned
From: Earth
Registered: 2005-01-24
Posts: 193

Re: hypersonic

I hate to ask this question, but how much do you think it would cost for NASA to develop and build a scramjet spaceplane such as the one you outline?


Far out in the uncharted backwaters of the unfashionable end of the Western Spiral arm of the Galaxy lies a small unregarded yellow sun.

             -The Hitchhiker's Guide to the Galaxy
              by Douglas Adams

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#48 2006-02-08 20:23:41

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,803
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Re: hypersonic

The budget for HL-20 was $2 billion. X-38 started with a budget pf $1.2 billion but after the expansion from 4 to 7 crew and all the other design changes, it ended up with a budget of $2 billion. So the $2 billion figure is reasonable for a small spacecraft, not including launch engines. The X-43A program cost $230 million. When X-43C was going to be a hydrocarbon dual-mode RAMjet / SCRAMjet it had a budget of $150 million. Budget for 2 engine development programs (LH2 SCRAMjet and kerosene supersonic combustion turbojet). The total comes to about $4 billion, including 2 flight vehicles.

I'm sure those justifying current expenditures would howl at that. One reason the cost can be kept down is to develop just a space taxi; no cargo hold, only 4 crew, just a cockpit seat each, no airlock, no robot arm. Use existing state-of-the-art heatshield technology, no new materials development. Start with existing lifting body knowledge and develop further with computer models. Emphasize computer analysis, not physical models and prototypes. The current Space Shuttle cost $10.1 billion including a new main engine, SRBs developed by enlarging Titan III SRBs and making them reusable, converting Saturn V assembly and launch facilities, developing new re-usable heatshield materials, new redundant computer (by connecting 4 existing model computers), new tires, new body shape, new arm, new spacesuit, new airlock, new toilet, new OMS and RCS thrusters. Everything was brand spanking new. Well, Canada paid for development of the arm and manufacture of the first one, NASA bought the other arms. This space taxi would use COTS computer, tires based on Shuttle tires, etc.

The launch facility would be an aircraft hanger and runway with an open piece of tarmac as safing area to fill fuel tanks. Use a standard aircraft tractor to tow it to the runway, and commercial fuel trucks with hoses to deliver both jet fuel and cryogenic LOX and LH2. Use the Shuttle's specialized truck to fill/empty hypergolic fuel tanks for on-orbit manoeuvring thrusters. In other words, no assembly/launch infrastructure. This thing could operate out of KSC or any Air Force airfield. It could even operate from a commercial airport that has an isolated patch of tarmac.

Let the flaming begin.

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#49 2006-02-09 02:25:17

Rxke
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From: Belgium
Registered: 2003-11-03
Posts: 3,669

Re: hypersonic

No airlock?? You mean it would taxi to where then?

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#50 2006-02-09 08:31:27

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,803
Website

Re: hypersonic

To ISS. Dock to the space station, then open the door. Or to an orbit assembled spacecraft for the Moon or Mars. If EVA is necessary, decompress the whole cabin like Gimini or Apollo.

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