What's getting in the way of speed? Is it just cost or is it, like usual, government regulation? Even in its heyday, the Concorde was only allowed to fly at its advertised speed over open ocean. I think it was "illegal" for them to fly a New York to LA route at those speeds.
Jack, in this case there is a reason for the regulation. The sonic boom will break windows and cause lots of other problems when flown over land, unless you are at a very high altitude (think SR-71). The military also has to be careful when doing that. Frankly, supersonic speed is great for catching up to someone or getting away from someone (I am thinking military jets). On the other hand, you can't shoot or turn very tightly at supersonic speed. For transport it would be great, but the cost is very high. Those safety and other regulations are important in this case.
I'm not an aerospace engineer but I did have the privilege of being on a design team that developed diagnostics for hypersonic tests conducted at the fabled Hanger 18 of the Air Force Research Laboratory at Wright-Patterson Air Force Base -- the one that houses the Alien Technology that we keep copying...
The difficulty with hypersonic speeds is that fuel/oxygen mixing and combustion at those speeds have more in common with cement mixing than the traditional jet engine problem of trying to keep a candle burning within a tornado. If the aircraft is not bringing along its own fuel and oxidant, as is the case with rocket propulsion, then the oxygen must be scooped up, mixed with fuel, and compressed before it is burned to create propulsive thrust. RAM Jets skip the traditional compression blades and use the velocity of the incoming air for compression, but ultimately slow some of the the air down to subsonic speed to mix with fuel efficiently. SCRAM jets are pushing the mixing technology so that fuel and air can be mixed at supersonic speeds. The X-51A Waverider is testing this technology.
It's not a regulation, management, licencing, cost thing. It's a lack of technology thing. Very similar to the reason why we don't have efficient solar-cell shingles on every roof --- great idea, but we are not there yet.
Yes, Rich, I also saw that CNN article, andI too was surprised. I was under the (perhaps mistaken) impression that speeds exceeding 600 mph would cause sonic booms that would be unacceptable to residents. And thus, there was a wall against faster speeds. Yet at 4,500 mph, why no sonic booms?
OK, that explains a lot. When I read the article -- which didn't address sonic booms -- I wondered whether the small size of the craft negated the sonic booms. Maybe they just take the boom over the ocean and move on.
Exceeding 660 miles per hour above sea level creates the boom. Once an aircraft breaks the sound barrier, it creats an extended boom that is heard by anyone who is near the supersonic craft. So it isn't just one single boom -- it's continuous as long as the craft is exceeding the the sound barrier, even if those on the ground experience it as a single boom. So, on a flight from L.A. to N.Y that exceeds the sound barrier, everyone on the ground between the two cities would experience the window-shaking (and sometimes window-breaking) boom.
NASA, however, is looking at strategies for taking the boom out of high speed aircraft:
It's interesting to see how fast aircraft technology advanced between the early years of flight and the commercial jet era. But Chuck Yeager broke the sound barrier over Edwards Air Force Base in 1947. And what has happened since? Commercial jets have been flying at top speeds of about 500-600 mph for a half-century.
The speed hasn't improved but there have been improvements elsewhere. Navigation, weather prediction, safety and on time performance have improved greatly. The cost of travel has remained about the same, so the cost corrected for inflation is actually less.
As mentioned in another post, the time on the ground has really climbed. Long security lines and long times to board and deplane because there is way too much carry on luggage and everyone is trying to squeeze their three bags in ahead of the next guy. The last few trips I've flown myself in my 40 year old 172, which is much slower than a 737 but without all the time on the ground the total trip is about the same. The total cost is actually cheaper because I'm able to bring my wife for the same cost of fuel.
Hi Chuck... As you know, the Bell X-1 was propelled by a rocket engine. The air-breathing supersonic engines of the Concord were "turbojet" engines, rather than the more traditional "turbofan" jet engines. The turbojet still required afterburners during takeoff and transonic transition and the combustors still needed to slow the intake air down to sub-sonic speeds. The Pratt & Whitney F119 engines used by the F-22 program provide supersonic flight without afterburner (supercruise), but only by using very expensive technology such as burn-resistant titanium alloy, integrally bladed rotors (disks and blades sculpted from a single block of alloy), and a highly-complex Full-Authority Digital Electronic Engine Control (FADEC) system. A 2009 estimate of F-22 per-copy cost is around $350 Million per plane. With a single pilot, that is $350 Million per Passenger. A Boeing 747-400 costs around $250 Million per copy and carries a maximum of 660 passengers (a paltry $380 Thousand per passenger - a 10^3 efficiency)
Until SCRAM Jet technology becomes more affordable from developments like the X-51, it looks like we will have plenty of time to appreciate the in-flight movie...
Thanks for a great explanation, Bill. Actually, I'm okay with longer flight times. If it took 60 minutes to fly cross-country, I'd probably be jumping on flights every week. This way, I get to stay home more.
Yes, Chuck, it has stalled because of the sound barrier. If a plane exceeds the sound barrier from the West Coast to the East Coast, the sonic boom is heard across the entire nation. Everyone below hears the boom. NASA is working on eliminating the boom. That's what it would take.
I recall as a kid growing up in Chicago during the Cuban Missile Crisis, supersonic defense jets would fly over Lake Michigan, rattling the windows in my second grade classroom. Sonic booms can indeed be disturbing.
I remember them, too, when I was a kid in the early-to-mid 1960s in Michigan. The boom was huge. I always enjoyed them in a kids-like-adventure way. But they really did rattle the windows and they were a shock to the system.
From my understanding, faster speed = high fuel consumption. During the days of the Concorde, high fuel consumption wasn't seen as a problem. Today, consumers and the market are more focused on things that, at least, appear to be good for the environment.
A transcontinental flight takes about five hours, wheels up to wheels down. Five hours to go 3000 miles is not too shabby, and there's no shock wave to be of concern.
I am constantly dismayed at the amount of time it takes, when using air travel, that is not actually in the air.
The airlines tell you to arrive 75 to 90 minutes before your departure, and you could spend up to 45 minutes waiting for your luggage at the other end. Tack on an additional 20 minutes or so taxiing to and from the gate. Call it 2-3/4 hours going effectively ZERO miles per hour.
Your average speed for your transcontinental flight isn't 600 miles per hour, it's 387, just two thirds the real speed of the plane.
Think about it. Sure the speed is the same as it was 40 years ago. The passenger loading process hasn't changed one bit for almost a century! It seems insane to load everyone single file through ONE door! The time a passenger jet spends on the ground not moving people is wasted revenue to an airline. An airline should be able to cut the turnaround time by at least 40% if more than one door is used. Sometimes that's done on jumbos, but it's still from ONE SIDE ONLY!
A widebody has two aisles. Why not load from both sides of the plane? And why not load from the rear as well? A jumbo could effectively be loaded from a four doors on two aisles.
Even a single aisle aircraft could be loaded from front and back. I've seen a single aisle aircraft unloaded a few times in this manner at the San Jose airport in California (Alaska Air), and that gets the plane empty fast.
Time is money. Cut the load / unload time, and make millions.
TJ, I'm surprised you haven't gotten more responses to your post – it hits the status-quo method very hard, and airline execs would cringe in light of the truths you profess. One similar technology scenario comes immediately to mind, and how new developments attempted to overcome it.
I'm referring to the component placement process for PCBs. Conventional process, currently used in millions of manufacturing facilities world-wide, uses the well-established "Chip-Shooter" method to place components plucked from tape/reel packaging, and robotically maneuvers individually components into precise location on the PCB while held by vacuum. But most sophisticated products have literally hundreds of components on their main board, so this Chip Shooter technology, while EXTREMETLY FAST and ACCURATE, still places them one at a time .... Like passengers on a plane going thru the front port-side cabin door.
The developed counter-solution to this was GANG-Placement technology, where literally scores of T&R components were dumped (a large gang batch at a time) thru a Z-axis filter, similar to the way the solder stencil was used at the front of the line, hitting all locations simultaneously.
Several big-name electronic giants (MOT) experimented with this technology several years ago, but I think the dream remained largely UN-realized; and so today the Chip-Shooter still remains the De-Facto Standard for solder component reflow automation in the world today.
I submit that passenger seating and dis-embarking would fare much better, using the simple, obvious suggestions which you've outlined. Kudos to your common sense.
Rich, this is an interesting development. You may not recall, but the X-15 rocket plane had a maximum speed of Mach 6.72, or 4,520MPH(7,274km.h). These planes flew from 1959 to 1970. They were piloted, dropped from a B-52 and landed like a plane. One interesting fact I found was that the ejection seat, which was never used, could be deployed up to Mach 4. That would be a wild ride.
So, why can these planes not be recovered or landed. I wonder. The space shuttle was basically landed automatically. The pilot was just there to take over in case of a problem.
naperlou... If you take a look at the dimensions and the image accompanying the Wikipedia article on the X-51A Waverider, you will notice it is tiny. Even a predator drone is longer by 2-ft and has a nearly 50-ft wingspan
X-51 Length: 25 ft, Empty Weight: 4,000 lb, Wingless (but for small control fins)
By the time you fill it with fuel and basic remote control electronics and communication equipment, there is not much room for exotic auto-navigation, landing, and recovery systems.
I'm not sure of our newest Naval equipment, but locating and retreiving what amounts to a 25' metal pipe at the bottom of the ocean does appear to be money well spent on design and development. I'm also going to assume that each test article has an automatic destruct just in case other nations are interested in diving for lost treasure...
The airlines are in the business of flying planes, much like the railroads were in the business of driving trains. The airlines don't care whether you make a flight or what happens to your bags, they just want to get your money. There's no incentive for them to get people on or off planes quickly because they have assigned takeoff and landing slots and cannot just get everyone on board quickly and take off the way a taxi could. Likewise, the airlines have no incentive to get luggage out to fliers in a timely way. The pilots landed the plane and got it to an assigned gate, end of story.
I recently learned the airline's PROFIT on a flight amounts to the cost of one economy ticket. So if you're on a flight with 150 people and they each pay $300 for the flight, the airline makes a profit of $300. The rest goes to expenses. Because the airlines run a low-margin business, fliers can expect poor service.
An unmanned experimental aircraft failed during an attempt to fly at six times the speed of sound in the latest setback for hypersonic flight.
The X-51A Waverider was designed to reach Mach 6, or 3,600 mph, after being dropped by a B-52 bomber off the Southern California coast on Tuesday. Engineers hoped it would sustain its top speed for five minutes, twice as long as an X-51A has gone before.
But the Air Force said Wednesday that a faulty control fin prevented it from starting its exotic scramjet engine and it was lost.
"It is unfortunate that a problem with this subsystem caused a termination before we could light the scramjet engine," Charlie Brink of the Air Force Research Laboratory at the Wright-Patterson Air Force Base in Ohio, said in a statement.
We still have a ways to go before we start to see comercial applications...
I didn't realize the margins for airlines were so slim, Jon. But I'm not surprised. For most flights I take, the cost if roughly that same as it was in the early 1970s. Needless to say, the flight experience was much better back then.
There is no commercial application for this technology. The lessons from Concorde and the 747, whoch both entered service in the same period, is that there is more proft in carrying more passangers for a minimal cost than providing a high priced high speed alternative to a privileged few. So there is no way a commercial aircraft manufacturer can expect to recover R&D costs and break even. (Concorde was partly government funded). We have the technology to build mach 2 airliners, but not the incentive - so what prospect for a mach 5 version? You may also have noticed that this test vehicle can neither take off nor land - two basic pre-requisites for commercial flight.
After reviewing this article and the several dozen comments posted, I'm surprised no-one has reacted to the Air Force's (Lack-of) Plan for recovery. To me, this is a design flaw from Square-One. If the cost of recovery exceeds the value of the development; well ,,,that speaks volumes to the cost of bureaucracy in the military today. Literally, flushing the experiment away, available for recovery by other salvaging interests. Really-?
Batar is certainly correct about the cost and viability of high speed flight. And, even more important than those sad economics, is that fact that air transport is still hamstrung and slowed by our "security" people, who are a huge waste of resources and a questionable value. They have certainly been able to make airports much less enjoyable than the second day of old aArmy basic training. So if one still needs to be at the airport two hours in advance of ones flight, the advantage of turning a two hour flight into a 15 minute flight is not so great any more.
It would be far more useful to research toward development of some form of matter transmission, which could happen at nearly the speed of light. THAT would be a worthwhile increase in speed.
You raise a good point about the security issues, William K. Every flight involves at least two extra hours on the front end and at least 30 minutes on the back -- and that's if the flight is on time. So, yes, there would defeinitely be an issue of diminishing returns if you change your Chicago-to-Detroit flight time from one hour to 15 minutes. You'd still have to waste a minimum of two-and-a-half hours at the airport.
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