Bad form, but your Comment about the XB70 Valkyrie prompted me to read it's wikipedia entry and I found this:
The biggest problem with sustained supersonic cruise is the buildup of heat due to skin friction. Duralumin, the traditional aircraft material, starts to go "plastic" at relatively low temperatures, and is unsuitable for continuous use above Mach 2.2-2.4. During the period that WS-110A was being studied, solutions to these problems were beginning to become available. New materials, especially titanium and stainless steel, were becoming more widely used in the industry, allowing operations at much higher temperatures.
Another concern for continued high-speed operation is the engines. Jet engines create thrust by increasing the temperature of the air they ingest, and as the aircraft speeds up, this air increases in temperature before it reaches the engines. The maximum temperature of the exhaust is determined by the materials in the turbine at the rear of the engine, so as the aircraft speeds up the difference in intake and exhaust temperature the engine can extract decreases, and the thrust along with it. Air cooling the turbine area was a key solution, which continued to improve though the 1950s and on to this day.
Intake design is also a major issue. The engine can only ingest subsonic air, so ramps in the intake are used to create shock waves that slow the airflow before it reaches the engine. Doing so removes energy from the airflow, causing drag. The key to reducing this drag was to use multiple small oblique shock waves, but this was difficult because the angle they made inside the intake changed with changes in Mach number. In order to efficiently operate across a range of speeds, the shock waves had to be "tuned." North American had already worked with advanced inlets on the A3J supersonic bomber for the U.S. Navy, which featured multiple ramps which were moved and angled automatically.
An aircraft able to operate for extended periods at supersonic speeds has a potential range advantage over a similar design operating subsonically. Most of the drag an aircraft sees while speeding up to supersonic speeds occurs just below the speed of sound, due to an aerodynamic effect known as wave drag. An aircraft that could fly past this speed saw a significant drag decrease, and could cruise supersonically with improved fuel economy. However, due to the way lift is generated supersonically, the lift-to-drag ratio of the aircraft as a whole drops, leading to lower range, offsetting or overturning this advantage.
The key to having low supersonic drag is to properly shape the overall aircraft to be long and skinny, as close as possible to a "perfect" shape, the von Karman ogive or Sears-Haack body. This has led to almost every supercruising aircraft looking very similar, with a very long and skinny fuselage and large delta wings, cf. SR-71, Concorde, etc. Although not ideal for passenger aircraft, the shaping is quite adaptable for bomber use.
the engines needed to push a large plane to go that fast are very noisy, no leaky turbofans here
In terms of passengers and cargo capacity Concorde was not a large aircraft. Well, as far as supersonic aircraft go the Concorde was big - Bigger than the B1 if I am not mistaken, and I have been at an airshow where a B1 did a few fly-by's (with and without 'burner - schweet...) and it is NOISY!
The Valkyrie never made it out of the prototype stage. IIRC the wingtips would fold downwards in supersonic cruise. It did make a maiden flight - and an F104 crashed into it and the program was killed. It sucks to think that this beauty was killed off due to no fault of its own. Yes the wingtips folded down.
With the TU144 retractable canards were needed to ensure stability at low speeds. Yes, and one crashed during an Airshow - grounding the project as well...
A conventional swept wing comes with flaps, slats and slots which are used to vary the shape of the wing (and make it considerably larger) for takeoff and landing. This creates more lift, at the expense of increased drag, which enables the aicraft to take off and land at much lower speeds. Yes, and with a delta having poor Angle of Attack characteristics and being inherently low drag the extra mechanics needed to make it behave like a conventional swept wing at low speeds is prohibitively heavy.
Uh I am a bit fuzzy on the details - used to be an aviation nut - but there is a payoff between fuel used/distance traveled/paying passengers.
Concorde just couldn't ride that fine balance economocally enough.
Then - most countries do not allow supesonic overflights - I remember concorde had to fly subsonic while over land and could only go supersonic while over the ocean on the trans atlantic crossing.
The Concorde was noisy - the engines needed to push a large plane to go that fast are very noisy, no leaky turbofans here - and with airports being so close to cities the overflights over suburban areas were problematic.
There is the issue of the optimum aerodynamic shape - there are basically three wing shapes: Swing wing (think B1 Bomber), works well in subsonic and supersonic flight - it is efficient during both flight profiles, but the mechanics is heavy. Probably the best option for the future.
"Normal" swept wings - not optimal for supersonic flight. Is the optimum configuration for carrying heavy loads long distances.
Delta Wings (Like the Concorde) - great for high speed flight, the Valkyrie bomber used a nice Delta wing design that "rode" the shock wave of supersonic flight at high speed to conserve fuel. It is not an optimum load carrying wing, and is not good for low-speed flight. Delta wings have a poor take-off and landing performance, i.e. it means that it lands and takes off at a high speed, and the landing profile is very "low" meaning it flies low over urban areas when taking off and landing. Also it needs a long runway to take off and land - the larger the plane the longer the runway needed. Whereas a wing for the A380 could be optimised for better performance in this flight envelope and not lose a lot of performance when it is actually airborne, for a delta the line to be walked is much finer.
Thus while the speed of supersonic flight would be great for international travel - plus the coolness factor - and there are technologies available today that were not available to the designers of the Concorde and Valkyrie (composite materials for one) there is still the trade-off of a wide range of flight envelopes (take-off, landing, subsonic flight, supersonic flight), size (the bigger you go the less efficient any design is), fuel use (supersonic flight uses a LOT of fuel - hence impacting plane size which makes the design less efficient and on and on) and then the greenies of course haha that makes large supersonic airlines not economically viable today.
Then also designing a supersonic superjumbo is a lot more expensive than is the case for a subsonic superjumbo. Development time is also much longer due to the newer tech, optimizing the design for all the flight profiles, engine design...
It is just not economically viable. It would actually make more sense to design a passenger liner that would "hop" into space to cross vast distances in the upper stratosphere and then fly down to land like a subsonic jetliner.
In South Africa (where I live) it is law that if traffice enforcement (speed traps or light running) is done via camera there have to be a warning sign a certain distance before the camera to warn drivers.
MHO, I don't think Microsoft is going to gain anything by taking over Apple, Yahoo OR Google. MS would for sure gain by buying out Apple or Google - Apple makes a better OS, and Google is a better online experience and makes better online products.
If MS could buy them out and squash them it would. That is also true for mos Linux distro's - If MS could buy out Canonical (ubuntu) and others it would - but for now they are just threatening lawsuits...
Err... I am not even from the US... don't label me a liberal tjom... I don't want to be affiliated with the US political system in any way - it gave us George Bush, among other dodgy presidents...
From the link you gave:
Turns out this is nothing new and not a difference between Leopard and Tiger. What you're seeing here, generally, is the difference between standard and sub-pixel anti-aliasing, two techniques for anti-aliasing text. Yes I am nitpicking, and it has nothing really to do with your point - which is a good point btw.
But, this is/. and hence I nitpick...
ps: it looks beautiful from across the room... how many actually did that haha...
Slashdot Mirror
If one could steal something like this, what else is available on the black market... a nuke!?
Another concern for continued high-speed operation is the engines. Jet engines create thrust by increasing the temperature of the air they ingest, and as the aircraft speeds up, this air increases in temperature before it reaches the engines. The maximum temperature of the exhaust is determined by the materials in the turbine at the rear of the engine, so as the aircraft speeds up the difference in intake and exhaust temperature the engine can extract decreases, and the thrust along with it. Air cooling the turbine area was a key solution, which continued to improve though the 1950s and on to this day.
Intake design is also a major issue. The engine can only ingest subsonic air, so ramps in the intake are used to create shock waves that slow the airflow before it reaches the engine. Doing so removes energy from the airflow, causing drag. The key to reducing this drag was to use multiple small oblique shock waves, but this was difficult because the angle they made inside the intake changed with changes in Mach number. In order to efficiently operate across a range of speeds, the shock waves had to be "tuned." North American had already worked with advanced inlets on the A3J supersonic bomber for the U.S. Navy, which featured multiple ramps which were moved and angled automatically.
An aircraft able to operate for extended periods at supersonic speeds has a potential range advantage over a similar design operating subsonically. Most of the drag an aircraft sees while speeding up to supersonic speeds occurs just below the speed of sound, due to an aerodynamic effect known as wave drag. An aircraft that could fly past this speed saw a significant drag decrease, and could cruise supersonically with improved fuel economy. However, due to the way lift is generated supersonically, the lift-to-drag ratio of the aircraft as a whole drops, leading to lower range, offsetting or overturning this advantage.
The key to having low supersonic drag is to properly shape the overall aircraft to be long and skinny, as close as possible to a "perfect" shape, the von Karman ogive or Sears-Haack body. This has led to almost every supercruising aircraft looking very similar, with a very long and skinny fuselage and large delta wings, cf. SR-71, Concorde, etc. Although not ideal for passenger aircraft, the shaping is quite adaptable for bomber use.
In terms of passengers and cargo capacity Concorde was not a large aircraft. Well, as far as supersonic aircraft go the Concorde was big - Bigger than the B1 if I am not mistaken, and I have been at an airshow where a B1 did a few fly-by's (with and without 'burner - schweet...) and it is NOISY! The Valkyrie never made it out of the prototype stage. IIRC the wingtips would fold downwards in supersonic cruise. It did make a maiden flight - and an F104 crashed into it and the program was killed. It sucks to think that this beauty was killed off due to no fault of its own. Yes the wingtips folded down. With the TU144 retractable canards were needed to ensure stability at low speeds. Yes, and one crashed during an Airshow - grounding the project as well... A conventional swept wing comes with flaps, slats and slots which are used to vary the shape of the wing (and make it considerably larger) for takeoff and landing. This creates more lift, at the expense of increased drag, which enables the aicraft to take off and land at much lower speeds. Yes, and with a delta having poor Angle of Attack characteristics and being inherently low drag the extra mechanics needed to make it behave like a conventional swept wing at low speeds is prohibitively heavy.
Yeah, I should've said "...make more sense, but would cost more to design..."
Uh I am a bit fuzzy on the details - used to be an aviation nut - but there is a payoff between fuel used/distance traveled/paying passengers.
Concorde just couldn't ride that fine balance economocally enough.
Then - most countries do not allow supesonic overflights - I remember concorde had to fly subsonic while over land and could only go supersonic while over the ocean on the trans atlantic crossing.
The Concorde was noisy - the engines needed to push a large plane to go that fast are very noisy, no leaky turbofans here - and with airports being so close to cities the overflights over suburban areas were problematic.
There is the issue of the optimum aerodynamic shape - there are basically three wing shapes: Swing wing (think B1 Bomber), works well in subsonic and supersonic flight - it is efficient during both flight profiles, but the mechanics is heavy. Probably the best option for the future.
"Normal" swept wings - not optimal for supersonic flight. Is the optimum configuration for carrying heavy loads long distances.
Delta Wings (Like the Concorde) - great for high speed flight, the Valkyrie bomber used a nice Delta wing design that "rode" the shock wave of supersonic flight at high speed to conserve fuel. It is not an optimum load carrying wing, and is not good for low-speed flight. Delta wings have a poor take-off and landing performance, i.e. it means that it lands and takes off at a high speed, and the landing profile is very "low" meaning it flies low over urban areas when taking off and landing. Also it needs a long runway to take off and land - the larger the plane the longer the runway needed. Whereas a wing for the A380 could be optimised for better performance in this flight envelope and not lose a lot of performance when it is actually airborne, for a delta the line to be walked is much finer.
Thus while the speed of supersonic flight would be great for international travel - plus the coolness factor - and there are technologies available today that were not available to the designers of the Concorde and Valkyrie (composite materials for one) there is still the trade-off of a wide range of flight envelopes (take-off, landing, subsonic flight, supersonic flight), size (the bigger you go the less efficient any design is), fuel use (supersonic flight uses a LOT of fuel - hence impacting plane size which makes the design less efficient and on and on) and then the greenies of course haha that makes large supersonic airlines not economically viable today.
Then also designing a supersonic superjumbo is a lot more expensive than is the case for a subsonic superjumbo. Development time is also much longer due to the newer tech, optimizing the design for all the flight profiles, engine design...
It is just not economically viable. It would actually make more sense to design a passenger liner that would "hop" into space to cross vast distances in the upper stratosphere and then fly down to land like a subsonic jetliner.
In South Africa (where I live) it is law that if traffice enforcement (speed traps or light running) is done via camera there have to be a warning sign a certain distance before the camera to warn drivers.
Really.
This is total and utter nonsense - just friggin move the satelite and prove for once and for all that patents such as these are dumb crap.
There. Said it.
No no. Yaol. Pronounced Y'all, like hillbillies do. Lucrative market that.
Ah - have you seen what hardware he is running? No way a future version of Windows would be able to run on hardware like that...
Oh heck - I am spreading the topping a bit thin aren't I...
In Soviet Russia Power Architecture use YOU!
I wonder how many of those scientists made their own concoctions? And would it be illegal drug abuse?
Who said anything about OSS?
Oh - and Maggies Farm is thee best Rage song EVA!
(ps: Thanks for the name - I forgot it... there goes five geek points...)
Yes. They should be barred. For Ever.
Next Question.
(Otherwise we won't have a Star-Trek future. If MSFT keeps going that guy will never get off the face of the planet to meet the Vulcans)
If MS could buy them out and squash them it would. That is also true for mos Linux distro's - If MS could buy out Canonical (ubuntu) and others it would - but for now they are just threatening lawsuits...
It DOES run Linux!
...>ahem and other OS's too... like Windows NT...
(mod me down if you must - but I just HAD to...)
Ah, now I get your post...
Err... I am not even from the US... don't label me a liberal tjom... I don't want to be affiliated with the US political system in any way - it gave us George Bush, among other dodgy presidents...
Now there's an inconvenient truth for you...
Phew...! Great Kool-Aid though...
Eep - was I wrong? I always thought Norton Antivirus was a Symantec product... or are you pulling my leg?
Hey... waidaminute... that wasn't me!
Yes. You said what I wanted - why should I trust the people who gave us Norton with my internet safety?
But, this is
ps: it looks beautiful from across the room... how many actually did that haha...
Ooh, and in both cases the switch will mean an improvement in quality of life for all!
I am holding out for Laser Eye Implants.
(Just don't go glaring at yourself in the mirror...)