PDA

View Full Version : Nasa plane to try Mach 7 flight


iGav
Mar 27, 2004, 06:07 AM
ready... steady... GOOOOOOOOOOOOOOOO!!!

http://news.bbc.co.uk/1/hi/sci/tech/3572909.stm

davecuse
Mar 27, 2004, 06:25 AM
If the many engineering challenges can be overcome, this propulsion technology could make it possible to fly, for example, from London to Sydney in just a couple of hours.

That would really be fantastic, I have to admit that I'm really shocked by the retirement of supersonic flight in commercial airlines. When's the last time we tooks steps to make travel slower?

It would have been especially nice on my last flight, as woman with her 3 young children were packed into 2 seats directly behind me, kids kicking my seat, crying, screaming. I put my seat back as far as I could and convinced the woman next to me to do the same just to put them in as much discomfort as I possibly could. Meanwhile the woman did not say one word to shut her kids up, I hate people like that. Lady if you're reading this, shut your kids up on the plane, tell them not to kick my seat, or better yet DRIVE!!!

takao
Mar 27, 2004, 07:02 AM
very nice news i was going to post it on my own but i had to go shopping before shops close :rolleyes:

i guess it will take long to be regular used in passenger planes

but there is no doubt (IMHO) who the main sponsor behind this is : US airforce
they would love to have a fast reaction time airplane (espaccially bomber) which can reach it's targets within hours..

kevin49093
Mar 27, 2004, 08:11 AM
It would have been especially nice on my last flight, as woman with her 3 young children were packed into 2 seats directly behind me, kids kicking my seat, crying, screaming. I put my seat back as far as I could and convinced the woman next to me to do the same just to put them in as much discomfort as I possibly could. Meanwhile the woman did not say one word to shut her kids up, I hate people like that. Lady if you're reading this, shut your kids up on the plane, tell them not to kick my seat, or better yet DRIVE!!!

Are you serious? That seems to be one of the rudest comments I have heard here... Lets see, instead of helping the situation by putting forth a bit of effort, you decided to convince someone else to help you make the situation worse for everyone. Great idea! I can't wait for the time you sit next to me any my family!! Have a great day!

wdlove
Mar 27, 2004, 11:49 AM
I certainly hope that this will be successful. We need to have a replacement for the now grounded Concorde. It is also interesting that the B-52, just keeps finding new uses. The work horse for the Air Force now for over 40 years.

G4scott
Mar 27, 2004, 03:25 PM
The B-52's in the air...

Another use they were talking about for this type of propulsion, is for cruise missiles, although I'm not sure how plausible that would be because, of altitude requirements, and the fact that these things have to be going pretty fast to move on their own power.

takao
Mar 27, 2004, 04:04 PM
Another use they were talking about for this type of propulsion, is for cruise missiles, although I'm not sure how plausible that would be because, of altitude requirements, and the fact that these things have to be going pretty fast to move on their own power.

perhaps but they need the b-52 for launching them ;)
but the B-52ies ar excpected to fly untill 2035 (or was it 2037)... where the B-52,B-1,B-2 should be replaced by one single type of aircraft

johnnowak
Mar 27, 2004, 04:19 PM
Are you serious? That seems to be one of the rudest comments I have heard here... Lets see, instead of helping the situation by putting forth a bit of effort, you decided to convince someone else to help you make the situation worse for everyone. Great idea! I can't wait for the time you sit next to me any my family!! Have a great day!

Hell that's nothing, I would've probably screamed at the woman, and if that failed, complained to whomever was in charge, and have their seats moved to cargo area.

Dont Hurt Me
Mar 27, 2004, 04:27 PM
The important part of the story is that this will not only lessen the cost to Orbit if successful but will simplify it. Instead of gigantic chemical boosters we can have a jet/scramjet/chemical booster hybrid that wont have to carry so much of the oxidizer. I hope this works out because we really need a jump in the technology to obtain orbit. for the most part we are using the same basic technology of V2 rockets from WW2. Its time to start exploring other avenues that will be cheaper,safer and less complex. I wonder how that Australian scram jet program is doing.

JesseJames
Mar 27, 2004, 04:33 PM
The important part of the story is that this will not only lessen the cost to Orbit if successful but will simplify it. Instead of gigantic chemical boosters we can have a jet/scramjet/chemical booster hybrid that wont have to carry so much of the oxidizer. I hope this works out because we really need a jump in the technology to obtain orbit. for the most part we are using the same basic technology of V2 rockets from WW2. Its time to start exploring other avenues that will be cheaper,safer and less complex. I wonder how that Australian scram jet program is doing.


******** A dude.

davecuse
Mar 27, 2004, 05:22 PM
Are you serious? That seems to be one of the rudest comments I have heard here... Lets see, instead of helping the situation by putting forth a bit of effort, you decided to convince someone else to help you make the situation worse for everyone. Great idea! I can't wait for the time you sit next to me any my family!! Have a great day!

Which would annoy you more....
a) Having your flight delayed 3 hours, then boarding to find 2 small children stuffed into the seat directly behind you screaming and kicking your seat for the entire flight, while the mother does not say one word to settle them down or explain that it's very rude to make someone's very expensive flight absolutely miserable.

b) Having the person in front of you put their seat in the resting position?

In my mind putting my seat back is part of why I chose to fly rather than drive. If I get a little chuckle out it.. all the better. I would hope that if you choose to travel by air with your family you exercise some authority and remind them that it's not courteous to kick the seat in front of you, also please for love of everything good make them pipe down! It is not my responsibility to keep someone else's kids in line.

That's just my $.02

Dave

Dont Hurt Me
Mar 27, 2004, 06:04 PM
Just to let you know the flight was successful. way to go! Awesome. they report 5,000 miles an hour and a ten second run. this really opens the door.

Opteron
Mar 27, 2004, 07:36 PM
Just to let you know the flight was successful. way to go! Awesome. they report 5,000 miles an hour and a ten second run. this really opens the door.

About time they got it to fly. The team from Brisbane uni, in Australia flew theirs over just under 2 years ago.

jsw
Mar 27, 2004, 07:45 PM
Well, then, Apple should've put a G5 into the plane so, for once and for all, they could get rid of that dumb Dell whining over "world's fastest computer".

kevin49093
Mar 27, 2004, 08:41 PM
Which would annoy you more....
a) Having your flight delayed 3 hours, then boarding to find 2 small children stuffed into the seat directly behind you screaming and kicking your seat for the entire flight, while the mother does not say one word to settle them down or explain that it's very rude to make someone's very expensive flight absolutely miserable.

b) Having the person in front of you put their seat in the resting position?

In my mind putting my seat back is part of why I chose to fly rather than drive. If I get a little chuckle out it.. all the better. I would hope that if you choose to travel by air with your family you exercise some authority and remind them that it's not courteous to kick the seat in front of you, also please for love of everything good make them pipe down! It is not my responsibility to keep someone else's kids in line.

That's just my $.02

Dave

Sure it gets annoying when someone is crying or carrying on behind me on a plane. But I don't think I have ever wanted to make the situation worse. My kids have had their tantrums on planes before (LA to Sydney!), and we try to control them the best we can, but they are kids! Try as we might, we can't always get our kids to "pipe down". They do what they want, when they want. We just try to control them, and help them pick quiet activities. (I'm not saying that if they want to run down the aisle and scream or kick seats, we let them!)

I also don't think it is your "responsibility to keep someone else's kids in line." But if you are ever faced with a situation like that, it takes far less energy to turn around and ask (nicely and honestly)if they would like it if you watched or played with one of their kids because it looks like their hands are full, and that soem people might be trying to sleep. (could you imagine traveling with three little kids? it sucks!) It is't your responsibility, but it is a nice thing to do that could easily help everyone out.


This reminds me of the time we had a sick kid in a hotel room. He was crying cuite a bit at about 7:00 pm. The front desk called and said we had to make our kids quiet down because they had a complaint. Needless to say, the head offices comped our stay when we told them about it...

vpalvarez
Mar 27, 2004, 09:10 PM
i guess it will take long to be regular used in passenger planes

but there is no doubt (IMHO) who the main sponsor behind this is : US airforce
they would love to have a fast reaction time airplane (espaccially bomber) which can reach it's targets within hours..

It definitely will take a long time. We first broke the sound barrier on Oct 4th, 1947. It took well over twenty years (Late 1969) for the first flight of the concorde, and that flight didn't have any passengers. I would say that if this technology was going to turn commercial it would take thirty years for the first scheduled flights, and possible a total of fifty years before they are widely available for the average air traveler.

billyboy
Mar 28, 2004, 05:01 AM
It took well over twenty years (Late 1969) for the first flight of the concorde, and that flight didn't have any passengers.

This latest 5000mph flight didnt even have a pilot!

davecuse
Mar 28, 2004, 05:24 AM
...it takes far less energy to turn around and ask (nicely and honestly)if they would like it if you watched or played with one of their kids because it looks like their hands are full, and that soem people might be trying to sleep. (could you imagine traveling with three little kids? it sucks!)

That sounds like a very nice solution, but what if the lady behind says "Yes, thank you so much, these kids are really a handful." then proceeds to tell little Johnny and Jane to come up a row and annoy me face to face.

That's a risk I'm just not willing to take.

The fact that her kids were crying screaming and being generally obnoxious wasn't what shocked me... It was the fact that she did not say one word to them the entire flight. Not one single attempt to try to calm them down, she was just sitting there reading a book, while her hooligans were making everyone else miserable.

thatwendigo
Mar 28, 2004, 06:20 AM
Sure it gets annoying when someone is crying or carrying on behind me on a plane. But I don't think I have ever wanted to make the situation worse. My kids have had their tantrums on planes before (LA to Sydney!), and we try to control them the best we can, but they are kids! Try as we might, we can't always get our kids to "pipe down". They do what they want, when they want. We just try to control them, and help them pick quiet activities. (I'm not saying that if they want to run down the aisle and scream or kick seats, we let them!)

I also don't think it is your "responsibility to keep someone else's kids in line." But if you are ever faced with a situation like that, it takes far less energy to turn around and ask (nicely and honestly)if they would like it if you watched or played with one of their kids because it looks like their hands are full, and that soem people might be trying to sleep. (could you imagine traveling with three little kids? it sucks!) It is't your responsibility, but it is a nice thing to do that could easily help everyone out.

This reminds me of the time we had a sick kid in a hotel room. He was crying cuite a bit at about 7:00 pm. The front desk called and said we had to make our kids quiet down because they had a complaint. Needless to say, the head offices comped our stay when we told them about it...

Then you abused the system, and got some people who I happen to know are only trying to do their jobs and keep everyone happy in trouble, all because you have to take your kids places with you. Honestly, I don't think I'm ever going to have kids, and a big part of that is that I don't want to turn into someone who thinks that the whole world has to revolve around my inability to control my spawn. You even say, outright, that "we try to control them the best we can, but they are kids! Try as we might, we can't always get our kids to "pipe down"."

Well, tough luck. Your problems controlling your children shouldn't be inflicted on everyone in an enclosed space, just because it's more convenient for you. In the plane, in that hotel, and anywhere else you take them, those children are your responsibility and your headache, not mine. The minute they start to do anything to me, you've crossed the line, because you are their legal guardian and responsible for their actions until they become old enough that the system considers them responsible for themselves. If you haven't discovered an effective way to get your kids to pipe down (reading material worked just fine, when I was younger), then you probably shouldn't be taking them out in public.

You know what another nice thing is, though? Not punishing everyone around you by bringing your unruly offpsring somewhere you already admit you know they might make a ruckus. Do you take them to the opera? Do you let them run around in a library? Why is the plane any different? It's not your only means of transportation, though it is one where you have at least a moderate social responsibility for being courteous to your temporary neighbors.

As a service industry worker, one who's had people like you inflict hell upon me for not wanting to just grin and bear the various atrocities carried out by undisciplined children, I hope that you someday learn to parent effectively. It's another of those things that would help everyone.

The important part of the story is that this will not only lessen the cost to Orbit if successful but will simplify it. Instead of gigantic chemical boosters we can have a jet/scramjet/chemical booster hybrid that wont have to carry so much of the oxidizer. I hope this works out because we really need a jump in the technology to obtain orbit. for the most part we are using the same basic technology of V2 rockets from WW2. Its time to start exploring other avenues that will be cheaper,safer and less complex. I wonder how that Australian scram jet program is doing.

I think Heinlein had a damn fine idea, myself, especially for unmanned cargo launch and retreival. We pick a mountain range near the equator, build a ten mile track that faces along the direction of rotation, and combine earth's momentum with magnetic impellers to railgun ferrous cannisters into space. The cannisters, at first, are carrying parts for the second stage of the operation, but soon after start to carry manufactered goods to be used in the intermediary space station. I could see a kind of railgun/scramjet cooperative system, where we throw them hard enough to get the compression for the chamber, then boost out to orbit and use chemical rockets for maneuvering in space.

The second stage is a skyhook, a chain-drive on a massive scale that hangs in geosynchronous orbit and lifts people to the launch facilities that allow transfer to other stations, the moon, and so on. We build it by launching parts up the well with the railgun, and then starting a couple of zero-G factories to produce the rest. After a while, the factories pay for themselves with materials that can't be fabbed in gravity, and we have a pretty reliable source of transport for leaving Earth without traditional chemical rockets. Space travel is another matter, though...

kevin49093
Mar 28, 2004, 10:27 AM
Then you abused the system, and got some people who I happen to know are only trying to do their jobs and keep everyone happy in trouble, all because you have to take your kids places with you. Honestly, I don't think I'm ever going to have kids, and a big part of that is that I don't want to turn into someone who thinks that the whole world has to revolve around my inability to control my spawn. You even say, outright, that "we try to control them the best we can, but they are kids! Try as we might, we can't always get our kids to "pipe down"."

Well, tough luck. Your problems controlling your children shouldn't be inflicted on everyone in an enclosed space, just because it's more convenient for you. In the plane, in that hotel, and anywhere else you take them, those children are your responsibility and your headache, not mine. The minute they start to do anything to me, you've crossed the line, because you are their legal guardian and responsible for their actions until they become old enough that the system considers them responsible for themselves. If you haven't discovered an effective way to get your kids to pipe down (reading material worked just fine, when I was younger), then you probably shouldn't be taking them out in public.

You know what another nice thing is, though? Not punishing everyone around you by bringing your unruly offpsring somewhere you already admit you know they might make a ruckus. Do you take them to the opera? Do you let them run around in a library? Why is the plane any different? It's not your only means of transportation, though it is one where you have at least a moderate social responsibility for being courteous to your temporary neighbors.

As a service industry worker, one who's had people like you inflict hell upon me for not wanting to just grin and bear the various atrocities carried out by undisciplined children, I hope that you someday learn to parent effectively. It's another of those things that would help everyone.


How is complaining about a phone call at 7:00 pm about a crying kid abusing the system? I would understand if it was at a time that people would be sleeping, but not in the early evening like that. Our complaint was not that we got a call, it was that the front desk worker very bluntly told us that we needed to stop our kids from crying. You can't always do that!

"Inability to control my spawn"? wow.. that's pretty a pretty cold comment. I don't think I have ever said that the whole world (or even a part of it) should revolve around me and my kids. I said that people should realize that kids can be tough at times.

I agree that there are some people who drag their kids everywhere and do not want to change their lives because of thier kids. We do not take our kids anywhere that might cause troubles if I can help it. We don't go out to dinner, movies, operas, or libraries, but we do have to take them on planes to visit family overseas. (If you say that is wrong, then I have nothing else to say.)

You "hope I learn to parent effectively"? Please, insult me a little more next time! My kids are very well behaved. They have two of the best parents in the world. I thik it is you that needs to learn a bit more about what it is really like to be a parent.

I guess the major difference between you and I is that I can deal with a bit of noise from kids. I realize that they are kids, not grownups who can't always just sit still, read and be quite for an extended period of time. (our kids are 28 months, 14 months, and 7 days)

thatwendigo
Mar 28, 2004, 04:55 PM
How is complaining about a phone call at 7:00 pm about a crying kid abusing the system? I would understand if it was at a time that people would be sleeping, but not in the early evening like that. Our complaint was not that we got a call, it was that the front desk worker very bluntly told us that we needed to stop our kids from crying. You can't always do that!

Whether or not you realize it, people who follow all kinds of schedules are in hotels, especially near airports. You might not have been in one with international travelers, but the principle is the same. Your child is causing someone else, a person who is a fully cognizant moral agent, discomfort. Maybe they're a businessman with an important project to work on, or maybe it's someone who's been driving all day and just wants to rest... No matter what the other circumstance, they have as much right to silence as you do to bring your kid with you, and you're the one committing a noise violation if someone in another room can hear you.

Sorry if you don't like it, but no matter how much parents wish to alter the balance of responsibility, I do not have to put up with your child's noise when I'm not on the clock.

"Inability to control my spawn"? wow.. that's pretty a pretty cold comment. I don't think I have ever said that the whole world (or even a part of it) should revolve around me and my kids. I said that people should realize that kids can be tough at times.

People realize it, and we give you leeway for it. Patience only goes so far, especially when I don't have the emotional clouding you do in regard to said noisemaker. Any claim that others should change their behavior just because you have a kid is foisting off responsibility from your own shoulders. A perfect example would be if I was talking to other adults in a public space, peppered my speech with some words you'd rather your offspring not know, and you get mad at me for it. I'm not the one who took them into a situation I couldn't control.

Also, my original comment was meant as a comment on my own likelihood of parenting, not at you. I saved that for later.

We don't go out to dinner, movies, operas, or libraries, but we do have to take them on planes to visit family overseas. (If you say that is wrong, then I have nothing else to say.)

Here's a nice story for you: When I was four, my family had to cross the country for a funeral. I behaved the whole way, staying quiet on the place because that's what I had been taught was the polite thing to do. I read, talked to my parents in a reasonable tone and volume, drew, and talked to the flight attendants. There weren't any problems with me.

Why can't you do that with your kids?

You "hope I learn to parent effectively"? Please, insult me a little more next time! My kids are very well behaved. They have two of the best parents in the world. I thik it is you that needs to learn a bit more about what it is really like to be a parent.

I've been helping to raise my siblings since I was five, which has included changing my youngest siblings' diapers at night, cooking and helping keep the pantry stocked, cleaning up, doing laundry, shuttling people around our family's busy schedule (when I was old enough to drive), being sure that homework was done, and quite a lot of the other responsibilities. My role didn't get as concentrated until I was around 10 or so, but that's when my mom's career really took off and I needed to step in and keep things running. It's only been in the last two years, since I moved away from home, that I haven't been active in raising children.

Oh, and one of them is autistic.

So, who needs more experience? I've been doing it for eighteen years.

I guess the major difference between you and I is that I can deal with a bit of noise from kids. I realize that they are kids, not grownups who can't always just sit still, read and be quite for an extended period of time. (our kids are 28 months, 14 months, and 7 days)

Let me repeat myself:
I have helped raise an eighteen year old, and a pair of twelve year olds. One of the youngest is autistic, which makes him far more difficult to deal with than you could imagine. However, I can get him to behave, without resorting to threats, spankings, or any other kind of trickery that parents often resort to.

Dr. Zauis
Mar 28, 2004, 05:44 PM
It's funny how this thread went from about a NASA plane to about parenting responsibilities.

On the plane topic. I read in the newpaper today that the plane goes 1.5 miles per second. That puts in more everyday figures compaired to it going 7 times the speed of sound.

wdlove
Mar 28, 2004, 06:16 PM
Congratulations NASA. This is great news for the future of Passenger travel.

http://www.nasa.gov/missions/research/x43_soars_feature.html

davecuse
Mar 28, 2004, 06:35 PM
It's funny how this thread went from about a NASA plane to about parenting responsibilities.

My fault I guess, sorry everyone.

On the plane topic. I read in the newpaper today that the plane goes 1.5 miles per second. That puts in more everyday figures compaired to it going 7 times the speed of sound.

That's really fast, I personally think that space exploration is going to see a boom similar to what personal computers have in the past 10 years. It's human nature to explore, history has shown that. I think we're entering a pretty exciting time. If you sit back and just think about everything that's going on right now, it's really mind boggling. The human genome is mapped, nanotechnology, we're moving away from petroleum to a completely renewable power source, information flows as freely as water, I have the world's knowledge at my fingertips.

In the big picture of things, I think that we are on the verge of writing names in the history books that will parallel Magellan, Columbus, and Drake. Maybe I'm putting more stock in the space program than I should be, but I don't think so.

kevin49093
Mar 28, 2004, 08:20 PM
My fault I guess, sorry everyone.



That's really fast, I personally think that space exploration is going to see a boom similar to what personal computers have in the past 10 years. It's human nature to explore, history has shown that. I think we're entering a pretty exciting time. If you sit back and just think about everything that's going on right now, it's really mind boggling. The human genome is mapped, nanotechnology, we're moving away from petroleum to a completely renewable power source, information flows as freely as water, I have the world's knowledge at my fingertips.

In the big picture of things, I think that we are on the verge of writing names in the history books that will parallel Magellan, Columbus, and Drake. Maybe I'm putting more stock in the space program than I should be, but I don't think so.

Thanks davecuse. I really didn't mean to get all worked up. I was just trying to make the point that sometimes if we act with more responsibility than others (i.e. the lady who did nothing on the plane) then it can sometimes help others as well as your self. I didn't think it was her right as a parent to let her kids be out of control.

As for the article. My students are going to be hearing quite a bit on this as soon as spring break is over!

thatwendigo
Mar 28, 2004, 08:26 PM
That's really fast, I personally think that space exploration is going to see a boom similar to what personal computers have in the past 10 years. It's human nature to explore, history has shown that. I think we're entering a pretty exciting time. If you sit back and just think about everything that's going on right now, it's really mind boggling. The human genome is mapped, nanotechnology, we're moving away from petroleum to a completely renewable power source, information flows as freely as water, I have the world's knowledge at my fingertips.

I tell you... We need a railgun to launch scramjets. The process coud completely bypass chemical rockets in-atmosphere by using geothermal, wind, and solar power to drive the impellers, throwing a scramjet orbiter up to the needed velocity so that it can climb out of the well and dock. If we keep stations over the equator, too, it's a simple matter of launch windows and fine adjustment, rather than entire course changes.

Dippo
Mar 28, 2004, 09:58 PM
I tell you... We need a railgun to launch scramjets. The process coud completely bypass chemical rockets in-atmosphere by using geothermal, wind, and solar power to drive the impellers, throwing a scramjet orbiter up to the needed velocity so that it can climb out of the well and dock. If we keep stations over the equator, too, it's a simple matter of launch windows and fine adjustment, rather than entire course changes.


Maglev launchers would be great, we could lauch into orbit without an engines at all. I'd hate to be in those g forces though.

Apple Hobo
Mar 29, 2004, 01:25 AM
The North American X-15 was a real man's plane.
Highest speed attained: mach 6.7 (about 4,500 MPH)
Highest altitude attained: over 350,000 feet (low Earth orbit)

To put the above figures into perspective, your average commercial airliner might fly at mach 0.82 at 37,000 feet.

All flown by hand by a human pilot. Oh yeah, this was in the 1960's when there were no gee-whiz-super-cool computers. Dangerous doesn't even begin to describe those research missions...

http://my.execpc.com/~culp/space/x15.jpg

iMook
Mar 29, 2004, 04:05 AM
BOMBERS:
Currently, I can think of no way a scramjet can ever replace the B-52 bomber (or any other offensive military aircraft, for that matter). Why? There have been documented cases of high-speed bomb drops where the bombs, instead of dropping out of the bomb bays like they were supposed to, instead hit the high-speed air layer flowing along the skin of the aircraft and bounced back into the bomb bay (and this was on EXISTING bombers). Just think of what would happen with a bomber that cannot travel slower than Mach 6 when it tries to launch a bomb. Just the turbulence created by breaking the smoothness of the aircraft's skin might be enough to wreak havoc on its payload.

External hardpoints are quite possibly also out of the question even if they could withstand Mach 7 air resistance, since in the moments just after release, the air layer running over the hardpoint would break, creating turbulence, and make the payload very difficult to control.

PASSENGER FLIGHTS:
Also, I don't think passenger flights would be at all economical with scramjet technology. Look at the size of the Pegasus rocket in comparison to the scramjet.
Let's make some rough ballpark calculations:
* The X-43A is a couple of feet shorter than a Dodge Viper (check it if you don't believe me)
* Now, scale it up to twice the size of a Learjet, so maybe more than a dozen people can fit in the passenger area.
* Similarly, scale up the booster (currently 17 m long). Assuming we're going to have great leaps in rocket efficiency, cut the proportional size in half.
* A Learjet 35A is about 48 feet long, which translates to 14.6 meters. So, we have a 30-meter-long scramjet, strapped to a booster that's now about 73 meters long, or three-quarters the length of a football field.
* This booster would also need to burn longer, since less acceleration = smaller g-forces on passengers, AND it would need to lift off from the ground. So, you'd actually need a BIGGER booster for passenger flight, even if you reduced the size a tad by making it air-breathing.
* Conclusion: To ferry the same number of passengers as a Learjet, you'd need a two-stage aircraft the length of a football field.
Is that more economical?

Addendum: Also consider that the current setup allows hypersonic flight for a few seconds. Any flight that'll draw customers towards hypersonic flight and away from conventional flight will need to be at least a few hours long. Tack on some more volume and weight for all that extra fuel.

Thus, I think that scramjets have the most promise as globetrotting cruise missiles or reusable spacecraft launch platforms. (Actually, using them cruise missiles probably wouldn't too practical, either, but I won't go into that unless by request)
Imagine a small-payload two-stage space shuttle replacement. Let's say the first stage (the booster) is also reusable. Conceivably, a size range similar to that described above for passenger flight could replace the current space shuttle and smaller rockets, lobbing small-to-mid-sized payloads into orbit. This is actually the only practical use I can think of for rocket-boosted scramjet craft...

...though it'd be pretty damn cool if they actually built a scramjet passenger craft. :D

GIANT MAGLEV LAUNCHER:
1. Maglev track (a la Shanghai Maglev train)
This is all well and good, but do you remember the massive hurdle the British supersonic car had to overcome? The sound barrier. Breaking the sound barrier with a tiny air layer beneath the car caused an extremely high-pressure wave to travel below the car, threatening to force the car airborne. I actually still don't know how they overcame this, but imagine the same thing but without such a high degree of aerodynamical optimization. (because it's not physically possible, due to the mechanism needed to constrain the projectile to the track) To put it mildly, the engineering involved would be nightmarish.

2. "Giant railgun" (a la BFG)
If a scramjet craft were magnetically launched in a fully enclosed barrel, the track-attachment problem would be solved, since the projectile would just float in the center of the barrel. The actual construction of a 10-mile-long magnet-laden tube (let's assume that this is sufficient) isn't that farfetched, since CERN's Large Hadron Collider is 26.7 km in circumference.
But, there is still the problem of boring a 10-mile-long giant tube AT AN ANGLE into the ground. The only equatorial place I could think of where the logistics wouldn't be staggeringly mind-boggling would be in the Andes. Boring the tunnels into a mountain has a few benefits:
a. Maintenance and rubble-removal tunnels could be bored in the side of the mountain, shortening them.
b. The mouth of the tunnel would be at a higher altitude, meaning thinner air, meaning less air resistance for the projectile to overcome during flight, meaning less energy needed to fire the launcher, meaning cheaper launches.
I think this is a neat idea for scramjet launch assists, acting like a hypersonic catapult.

In summary, I think that scramjet technology would not be economical or practical for currently envisioned application outside of spacecraft launching, and I think that both chemical boosting and maglev catapulting are relatively viable methods.

P.S. - Then again, the scramjet's minimum operational speed would increase on its trip to space, as the air would become thinner, requiring higher compression ratios for scramjet ignition.

Just my two cents.

billyboy
Mar 29, 2004, 07:40 AM
My fault I guess, sorry everyone.



That's really fast, I personally think that space exploration is going to see a boom similar to what personal computers have in the past 10 years. It's human nature to explore, history has shown that. I think we're entering a pretty exciting time. If you sit back and just think about everything that's going on right now, it's really mind boggling. The human genome is mapped, nanotechnology, we're moving away from petroleum to a completely renewable power source, information flows as freely as water, I have the world's knowledge at my fingertips.

In the big picture of things, I think that we are on the verge of writing names in the history books that will parallel Magellan, Columbus, and Drake. Maybe I'm putting more stock in the space program than I should be, but I don't think so.

Yeah, we are so advanced, 50% of the world has still not made a phone call :rolleyes: and millions still die in silence from malaria while we read hundreds of column inches on a handful dying from SARS, and AIDS is controlled in the West while it threatens to destroy African society - and some machine hits 5000 mph yet still we have no G5 Powerbooks.

davecuse
Mar 29, 2004, 10:48 AM
Yeah, we are so advanced, 50% of the world has still not made a phone call :rolleyes: and millions still die in silence from malaria while we read hundreds of column inches on a handful dying from SARS, and AIDS is controlled in the West while it threatens to destroy African society - and some machine hits 5000 mph yet still we have no G5 Powerbooks.

In time... anything is possible, someone just has to figure out how. This is one of the most exciting principles behind nanotechnology, it could effectively end disease. Sure it may take a while, but it could definitely happen.

evil
Mar 29, 2004, 11:00 AM
just another example of u.s government sponsored money wasting.
how about spending that 250 million dollars to actually help citizens instead of trying to fly faster and faster.

javabear90
Mar 29, 2004, 11:41 AM
hmmm... couldn't you attach a scram jet or ramjet, or jet engine, or somthing big a expensive that provides lots of thurst on a maglev train. Could you have maglevs that went accross the country in 30 minutes? and have a network of them all accross the contenent. It is not like you can run a train into a building or anything. So... I don't think their would have to be that high security.

I dunno... Just a thought.

iMook
Mar 29, 2004, 02:26 PM
hmmm... couldn't you attach a scram jet or ramjet, or jet engine, or somthing big a expensive that provides lots of thurst on a maglev train. Could you have maglevs that went accross the country in 30 minutes? and have a network of them all accross the contenent. It is not like you can run a train into a building or anything. So... I don't think their would have to be that high security.

I dunno... Just a thought.

Errrr... last time I checked, no one has ever even TRIED to break the sound barrier using a maglev, much less travel at Mach 7. And yes, you can put a jet engine on almost anything, a jet-turbine-propelled 18-wheeler cab has jumped the Rio Grande before. So yes, I guess you CAN just stick a bunch of jet engines on a maglev... but what would be the point?

Oh yes, seeing as how high-temperature semiconducting is still in its infancy, barring a MAJOR breakthrough, you won't be seeing transcontinental maglevs (or even interstate maglevs) anytime soon. It's just too expensive to keep a Mississippi of liquid nitrogen cold.

P.S. - pet peeve of mine: *something, *continent, *across, *thrust, *there

iMook
Mar 29, 2004, 02:29 PM
Was the X-15 air-breathing? Somehow I don't remember it was. Oh well, I'm too lazy to look it up. :D

Mr. Anderson
Mar 30, 2004, 09:47 PM
Was the X-15 air-breathing? Somehow I don't remember it was. Oh well, I'm too lazy to look it up. :D

No it was a rocket. The last flight did have a prototype scramjet, but the materials weren't up to par with the temps it had to take and it melted away. Funding was cut for the shuttle, so we never saw a orbital X-15 - which was the next phase of the project....

This is great stuff and the only sad part is that we'll have to wait quite some time before these will ever get to be commercial and fly passengers ....

D

thatwendigo
Mar 31, 2004, 12:08 AM
Thus, I think that scramjets have the most promise as globetrotting cruise missiles or reusable spacecraft launch platforms. (Actually, using them cruise missiles probably wouldn't too practical, either, but I won't go into that unless by request)
Imagine a small-payload two-stage space shuttle replacement. Let's say the first stage (the booster) is also reusable. Conceivably, a size range similar to that described above for passenger flight could replace the current space shuttle and smaller rockets, lobbing small-to-mid-sized payloads into orbit. This is actually the only practical use I can think of for rocket-boosted scramjet craft...

And somewhat similar to what I'm suggesting, though you're talking about rockets, and I'm talking about magnetic impellers. :cool:

2. "Giant railgun" (a la BFG)
If a scramjet craft were magnetically launched in a fully enclosed barrel, the track-attachment problem would be solved, since the projectile would just float in the center of the barrel. The actual construction of a 10-mile-long magnet-laden tube (let's assume that this is sufficient) isn't that farfetched, since CERN's Large Hadron Collider is 26.7 km in circumference.
But, there is still the problem of boring a 10-mile-long giant tube AT AN ANGLE into the ground. The only equatorial place I could think of where the logistics wouldn't be staggeringly mind-boggling would be in the Andes. Boring the tunnels into a mountain has a few benefits:
a. Maintenance and rubble-removal tunnels could be bored in the side of the mountain, shortening them.
b. The mouth of the tunnel would be at a higher altitude, meaning thinner air, meaning less air resistance for the projectile to overcome during flight, meaning less energy needed to fire the launcher, meaning cheaper launches.
I think this is a neat idea for scramjet launch assists, acting like a hypersonic catapult.

I seem to recall there being a couple of nearly optimal sites listed in The Moon is a Harsh Mistress, which I freely admit is what got me into the basic idea of a magnetic launcher. Supposedly, the Tibetan plateau is almost as good as the Andes, as are a couple of other really high mountains. In addition to the logistical reasons you gave, mountains tend to add rigid support, the absence of civilian population that would be disturbed by the supersonic takeoffs, and some pretty favorable cooling conditions for the launcher rails (depending on location).

The opposite idea, that of a magnetic launcher on the moon that sends lunar hydroponics, solid materials (mined metals, certain rocks, etc.), and other non-living objects back down the well in sealed canisters that are cheaply manufactured using rock, bands of ferrous material, and sealants. They're splashed down in the ocean, recovered, and cracked to harvest their paylods.

This raises issues of lunar ecology and the strip-mining of the moon, but I don't think we're going to be taking anything that actively supports life, unlike the equal practice down here on earth.

P.S. - Then again, the scramjet's minimum operational speed would increase on its trip to space, as the air would become thinner, requiring higher compression ratios for scramjet ignition.

So throw them harder. :D