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An audiophile and petrolhead's journal: Buckle up! - Page 156

post #2326 of 9498
Supersonic flight for passengers? Not in the foreseeable future. Even if the ban of supersonic flight over the USA were lifted, the combination of exotic materials required to deal with heat, fuel consumption and a much smaller carrying capacity makes supersonic passenger service financially nonviable. Passenger service is all about maximizing the number of people (or freight) you can move for the least cost. If you make a plane that can carry more passengers for less money, you will sell planes. Otherwise, the airlines will just upgrade the avionics and engines for the planes they already own.

Supersonic bombers also don't really make a lot of sense. They light-up with IR heat signatures and that makes them sitting ducks for SAM sites and interceptor aircraft like the F22. Anything a supersonic bomber can do, an unmanned ICBM or stealthy cruise missile can do better.

So - outside of fighters, supersonic doesn't make sense. Now, if we could do hypersonic (Mach 5+) for the same cost as the current transonic planes - then I think it's a whole new ball game! wink.gif

The SR71 still officially holds most of the airplane speed records for "air-breathing aircraft" - that makes it different from rocket powered aircraft like the X-15 or the reentry of orbiting vehicles like the Shuttle or Apollo. There have been other aircraft that could do Mach 3 - like the Mig-25 - however that wasn't a sustained cruising speed - it was a maximum dash speed. Most of the top-line fighters have max speeds of between ~Mach 2 - 2.5. When you go over that, you start to need to think about more exotic materials to withstand the heat, special fuels, etc.
Edited by billybob_jcv - 3/22/13 at 10:39pm
post #2327 of 9498
Thread Starter 
If memory serves, fuel consumption for supersonic (Mach 2+) flight is unbelieveable. The Concord was essentially just a very aerodynamic, flying, Zippo lighter. smily_headphones1.gif
post #2328 of 9498
Quote:
Originally Posted by billybob_jcv View Post

Supersonic flight for passengers? Not in the foreseeable future. Even if the ban of supersonic flight over the USA were lifted, the combination of exotic materials required to deal with heat, fuel consumption and a much smaller carrying capacity makes supersonic passenger service financially nonviable. Passenger service is all about maximizing the number of people (or freight) you can move for the least cost. If you make a plane that can carry more passengers for less money, you will sell planes. Otherwise, the airlines will just upgrade the avionics and engines for the planes they already own.

Supersonic bombers also don't really make a lot of sense. They light-up with IR heat signatures and that makes them sitting ducks for SAM sites and interceptor aircraft like the F22. Anything a supersonic bomber can do, an unmanned ICBM or stealthy cruise missile can do better.

So - outside of fighters, supersonic doesn't make sense. Now, if we could do hypersonic (Mach 5+) for the same cost as the current transonic planes - then I think it's a whole new ball game! wink.gif

You might like to look up the LAPCAT study if you're interested in hypersonic airliners.

 

 


Quote:
Originally Posted by Magick Man View Post

If memory serves, fuel consumption for supersonic (Mach 2+) flight is unbelievable  The Concord was essentially just a very aerodynamic, flying, Zippo lighter. smily_headphones1.gif

It was stupidly inefficient when at low speed as well, it's supercruise efficiency seems really high in comparison.


Edited by Tangster - 3/22/13 at 10:40pm
post #2329 of 9498
LAPCAT is not the first of those types of studies. I worked for a short time on an advanced propulsion study at Northrop in ~1990. We were looking at using engines that used some sort of solid fuel slurry that theoretically had some ungodly energy/lb spec to drive vehicles to Mach 5+. It was just a theoretical exercise, and all I did for it was some back of the envelope drag estimation for the vehicle shapes they were considering.

The other really interesting project was from the 1980's: NASP. I didn't work on that one, but I did attend a briefing. At that time, they were considering shaping the bottom of the plane like half of a Shuttle nozzle, then injecting fuel directly under the vehicle. The whole bottom of the vehicle would then be a ramjet. Pretty wild stuff.
post #2330 of 9498
Thread Starter 
Didn't they make scramjet prototypes capable of Mach 7-8 but were never declassified? I remember reading testimonies of folks in the Arizona and Nevada deserts saying they heard 6, 7, or even 8 booms in succession. I believe it, there are manned aircraft faster than the SR-71, but I believe they implement some pretty exotic respiration systems.


So no one gives two squawks about the Merc/McLaren SLR? Okay, yeah, I see how it is. tongue.gifbiggrin.gif I was going to go into detail about the history of that particular car and previous owner but, you know, whatever...
Edited by Magick Man - 3/22/13 at 11:25pm
post #2331 of 9498
Spill the beans Magick!
I am a Mercman and I love the SLR and the SLS.
post #2332 of 9498
Quote:
Originally Posted by billybob_jcv View Post

I once met Bill Park .

That's just downright cool. eek.gif


Quote:
Originally Posted by veyrongatti View Post

So supersonic flight will never come back? 

Billy probably knows better than I do (or than anyone else here does), but FWIR/AFAIK it's unlikely - Concorde was stupid expensive to operate (iirc it was like $8-12k/seat for passengers, and there were pretty serious limitations on luggage/etc due to weight (I have no idea how they'd handle modern customers who weigh in a 300-700 lbs per person ph34r.gif)).

The fuel economy thing is a piece of it - Wikipedia has a nice comparison between fuel economy and passenger carrying looking at Concorde vs 747-400:

Passenger miles/US Gallon:
Concorde: 14
747-400: 91

That's pretty dramatic, especially when fuel has probably gone up 10x in price since the late 1960s and today.

There's also the whole public fear thing (same reason nuclear reactors haven't become the de facto standard for power in the US) - if it's blown up live on CNN, it will probably never be commercially successful. rolleyes.gif


Quote:
Originally Posted by billybob_jcv View Post

Supersonic flight for passengers? Not in the foreseeable future. Even if the ban of supersonic flight over the USA were lifted, the combination of exotic materials required to deal with heat, fuel consumption and a much smaller carrying capacity makes supersonic passenger service financially nonviable. Passenger service is all about maximizing the number of people (or freight) you can move for the least cost. If you make a plane that can carry more passengers for less money, you will sell planes. Otherwise, the airlines will just upgrade the avionics and engines for the planes they already own.

This is also my understanding, more or less. Isn't the "next big thing" supposed to be spaceplanes, because they get to the whole "lower operating cost/speed" thing better than Concorde?
Quote:
So - outside of fighters, supersonic doesn't make sense. Now, if we could do hypersonic (Mach 5+) for the same cost as the current transonic planes - then I think it's a whole new ball game! wink.gif

Wouldn't that require some sort of, gee idk, world-altering scientific breakthrough? tongue.gif
Quote:
The SR71 still officially holds most of the airplane speed records for "air-breathing aircraft" - that makes it different from rocket powered aircraft like the X-15 or the reentry of orbiting vehicles like the Shuttle or Apollo. There have been other aircraft that could do Mach 3 - like the Mig-25 - however that wasn't a sustained cruising speed - it was a maximum dash speed. Most of the top-line fighters have max speeds of between ~Mach 2 - 2.5. When you go over that, you start to need to think about more exotic materials to withstand the heat, special fuels, etc.

Doesn't it also hold the cruising altitude records, or have the various spaceplane prototypes started to take those?

Quote:
Originally Posted by Magick Man View Post

Didn't they make scramjet prototypes capable of Mach 7-8 but were never declassified? I remember reading testimonies of folks in the Arizona and Nevada deserts saying they heard 6, 7, or even 8 booms in succession. I believe it, there are manned aircraft faster than the SR-71, but I believe they implement some pretty exotic respiration systems.

I thought X-15 did Mach 6-7?

Or are you talking about "Aurora" (the Illuminati of aircraft...tongue_smile.gif).
Quote:
So no one gives two squawks about the Merc/McLaren SLR? Okay, yeah, I see how it is. tongue.gifbiggrin.gif I was going to go into detail about the history of that particular car and previous owner but, you know, whatever...

Hey man -

Your car can do like 200mph, we're talking about things that can do like, 2000mph. I mean sure, you can go hop in your car right now and party down, while getting into any of these aircraft would likely be impossible, but still...redface.gif
post #2333 of 9498
I was afraid to comment on the SLR because I thought I had missed when you talked about buying it! I went back in the thread trying to find where you mentioned purchasing an SLR and couldn't find it!

On the scramjet - there are lots of stories about mysterious sightings of an odd pulsed contrail - usually called "donuts on a rope" - from a vehicle dubbed "Aurora". This is usually combined with a discussion about how the military would have never retired the SR71 unless they had something better. There's also been many other unclassified and rumored research programs related to hypersonic & suborbital vehicles. X-20, X-33, X-37, X-40, X-43, X-51, Hypersoar, Venturestar, Blackstar, etc, etc, etc!

For me, any information that the nut jobs like Bill Sweetman & Bob Lazar talk about is seriously suspect. Those guys are a complete joke - and the fact that Sweetman is now at AvWeek says a lot about how far AvWeek has fallen since the 1980s & 90s.

FYI - the number of sonic booms is not related to the speed - you don't get two sonic booms at Mach 2 and three at Mach 3. Multiple sonic booms are caused by having multiple shockwaves being generated from points far enough apart on the vehicle for the two booms to be distinctly heard. For example, the shuttle generates a shockwave at the nose and at the wings, and that's the famous "double boom" that we in SoCal hear every time the shuttle lands at Edwards AFB. I'm not sure what would cause 7 or 8 booms - my first thought would multiple vehicles, but I'm not aware of anything that would fly in formation while going supersonic - that would be nuts.




The X-15 was a rocket plane, not air-breathing.
Edited by billybob_jcv - 3/23/13 at 9:20am
post #2334 of 9498
Thread Starter 
Yeah, I bought the SLR at the same time we bought the older Mini Cooper. Mine was the N. America "show car", displayed at the LA, Chicago, and NYC auto shows, before being purchased by Lakers head coach Phil Jackson, who put a grand total of 110 miles on it. blink.gif Well, it already has triple that amount now. Heh. This also the 2nd car I've bought that was shown at the NYC auto show. What are the odds of that? FWIW, I really like the SLR, and even more after the upgrades. I have no idea why Mercedes didn't ship that car with a locking diff, but it needs it, badly. Major oversight by them. It's like driving an extremely well-setup muscle car, the roar and overrun will curdle your blood. It's pure petrolhead porn. I'm not quite sure which is the better car, the SLR or the Vanquish S, overall, they're both incredible GT monsters. The Merc is faster, though, while the Vanq has a real manual tranny and better interior (the best seats of any car I own, fit me like a tailored suit).
Quote:
FYI - the number of sonic booms is not related to the speed - you don't get two sonic booms at Mach 2 and three at Mach 3. Multiple sonic booms are caused by having multiple shockwaves being generated from points far enough apart on the vehicle for the two booms to be distinctly heard. For example, the shuttle generates a shockwave at the nose and at the wings, and that's the famous "double boom" that we in SoCal hear every time the shuttle lands at Edwards AFB. I'm not sure what would cause 7 or 8 booms - my first thought would multiple vehicles, but I'm not aware of anything that would fly in formation while going supersonic - that would be nuts.

Well crap, you're right. I've been living under a false assumption about sonic booms for years (and so have many UFO/conspiracy nuts, apparently). frown.gif Oh well. Does make me wonder what it is, I've personally seen video recording the phenomenon.
post #2335 of 9498
There is one place where we could see new supersonic civilian aircraft: high-end private business jets. There's companies working on designs and I think it will happen. When a mogul wants to get from Abu Dhabi to Hong Kong, and they want to do it Right Now, they will happily pay the price. Most of the biz jets are owned by companies that provide time-sharing services, so as long as they see demand, they'll be willing to purchase the planes.
post #2336 of 9498
Quote:
Originally Posted by billybob_jcv View Post


For me, any information that the nut jobs like Bill Sweetman & Bob Lazar talk about is seriously suspect. Those guys are a complete joke - and the fact that Sweetman is now at AvWeek says a lot about how far AvWeek has fallen since the 1980s & 90s.

ph34r.gif
Quote:
The X-15 was a rocket plane, not air-breathing.

Yeah I know its rocket powered, I'm just vaguely remembering that it holds some insane speed record (iirc isn't the fastest manned air vehicle, apart from spacecraft on re-entry?)...
post #2337 of 9498
Quote:
Originally Posted by obobskivich View Post

ph34r.gif
Yeah I know its rocket powered, I'm just vaguely remembering that it holds some insane speed record (iirc isn't the fastest manned air vehicle, apart from spacecraft on re-entry?)...

Yes - absolutely. A little over 4500 MPH, I think - something like that. At the edge of space, the Mach number starts to no longer make sense because there's not enough air for the speed of sound to be defined.

the X-43A is now the official air-breathing vehicle record holder (unmanned) at ~7000 MPH! http://www.nasa.gov/missions/research/x43-main.html

Of course, all these X-planes are just for research. The X-43A scramjet engine only operated for ~12 seconds. The X-51 Waverider's scramjet operated for ~200 seconds, but it "only" did a little over Mach 5 @ 70,000 feet. The X-51 has flown 3 times, and all 3 times there were some issues that prevented it from being a completely successful test. We're still a loooooong way from putting passengers on a hypersonic airliner!

Personally, I'm betting on a maglev linear accelerator ballistic system. You sit in a bullet shaped vehicle, and your are shot in a ballistic trajectory into a magnetic decelerator. It will be like playing catch across the Pacific Ocean! One of my other ideas is a pneumatic tube based system, like those vacuum canisters used in some old businesses & banks to move checks and invoices from one floor to the next. With those, you would essentially be "flushed" to your destination! I've got a million ideas for global mass transportation... tongue.gif
post #2338 of 9498
Quote:
Originally Posted by billybob_jcv View Post

One of my other ideas is a pneumatic tube based system, like those vacuum canisters used in some old businesses & banks to move checks and invoices from one floor to the next. With those, you would essentially be "flushed" to your destination! I've got a million ideas for global mass transportation... tongue.gif

I've heard of that before. A maglev train in a vacuum tube could go silly fast without the pesky downside of air resistance.

post #2339 of 9498
Quote:
Originally Posted by billybob_jcv View Post

One of my other ideas is a pneumatic tube based system, like those vacuum canisters used in some old businesses & banks to move checks and invoices from one floor to the next. With those, you would essentially be "flushed" to your destination! I've got a million ideas for global mass transportation... tongue.gif

Somebody has been watching too much Futurama. tongue.gif
Quote:
Originally Posted by Tangster View Post

I've heard of that before. A maglev train in a vacuum tube could go silly fast without the pesky downside of air resistance.

What happens if you have a power outage in this scenario? Just saying...ph34r.gif
post #2340 of 9498
Quote:
Originally Posted by Magick Man View Post

Yeah, I bought the SLR at the same time we bought the older Mini Cooper. Mine was the N. America "show car", displayed at the LA, Chicago, and NYC auto shows, before being purchased by Lakers head coach Phil Jackson, who put a grand total of 110 miles on it. blink.gif Well, it already has triple that amount now. Heh. This also the 2nd car I've bought that was shown at the NYC auto show. What are the odds of that? FWIW, I really like the SLR, and even more after the upgrades. I have no idea why Mercedes didn't ship that car with a locking diff, but it needs it, badly. Major oversight by them. It's like driving an extremely well-setup muscle car, the roar and overrun will curdle your blood. It's pure petrolhead porn. I'm not quite sure which is the better car, the SLR or the Vanquish S, overall, they're both incredible GT monsters. The Merc is faster, though, while the Vanq has a real manual tranny and better interior (the best seats of any car I own, fit me like a tailored suit).

Who put those stealth black stuff thingys? 

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