I’m perusing a story on CNN about a vehicle that can fly at Mach 6, or more than 4,500 miles/hr. While that seems like a crazy speed, my response is, what took so long?
I think about that almost every time I board a plane these days. It took the same six or so hours to fly across the US 20 years ago that it does now. I know that the cockpits have changed significantly, and other improvements have been made, but flight times haven’t budged. And yes, I’m aware of the whole Concorde thing, and it’s really a shame that the program had to be cancelled.
Back to the story on CNN. Does it mean that we’re actually going to see faster commercial airplanes? Not likely, or at least not anytime soon. The Pentagon’s X-51A Waverider hypersonic flight test vehicle is just that -- a test vehicle.
Later today, the 25-foot-long vehicle will be dropped off of the wing of a converted B-52 bomber off the California coast. It will attempt to fly for five minutes at Mach 6. Remember, Orville and Wilbur’s first flight only last a few seconds. According to the story, “The technology could eventually bring missiles or airplanes to the other side of the planet in minutes instead of hours.”
If successful, the test plane will simply fade into the Pacific Ocean and not be recovered. The Air Force claims that it’s prohibitively expensive to try to recover the planes. The cost of the program was not disclosed.
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.
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:
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.
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.
Are they robots or androids? We're not exactly sure. Each talking, gesturing Geminoid looks exactly like a real individual, starting with their creator, professor Hiroshi Ishiguro of Osaka University in Japan.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.