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The Future of Flight
Roland Piquepaille writes "With "High Times," the Economist delivers a very long and extremely well-documented article about the future of aviation during the next fifty years. It tells us about pilotless planes, with 32 countries currently developing more than 250 models of unmanned aerial vehicles (UAV), primarily for combat purposes. The article also looks at future civilian pilotless planes and at the future of personal aviation. But what captivated my attention in this article was the last part about future commercial supersonic and hypersonic (at least five times the speed of sound) planes. In particular, the Economist describes the HyperSoar. "The HyperSoar is a concept for a craft flying at ten times the speed of sound and able to reach any point on the globe within two hours." This overview contains more details and references about the HyperSoar which would fly from Los Angeles to New York in 35 minutes."
hmm, I thought High Times was a publication of a different sort...
Enough said.
"Eve of Destruction", it's not just for old hippies anymore...
But even with that fact HyperSoar which would fly from Los Angeles to New York in 35 minutes. How long would you have to wait at the airport to get on the plane?
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I've done a few tests in X-Plane and came to the conclusion that with today's rockets and advanced materials it might be fairly easy to make a suborbital plane that can go from Paris to New-York in under an hour. I've got three different designs that could do it. The one obstacle is leading edge temperature at supersonic and hypersonic speeds, but shockwave shaping and the use of cryogenic fluid (liquid hydrogen ?) like on the 70s' XB-70 Valkyrie can overcome it.
Maybe we deserve this world ?
"If cars were meant to fly, God would have given them wings", Bishop Milton Wright, 1903
You are not your blog
Although the article did a good job of discussing flight technology, they did not say enough on the market forces that might drive different scenarios. Its not clear whether Boeing's vision of direct point-to-point travel or Airbus's visions of mass-transit hub-and-spoke will be the future of air travel. On the one hand, the decline in business travel hurts the economics of offering quick direct flights to everywhere while new technologies like free flight aid point-to-point travel. On the other hand, its not clear whether people will tolerate multiple connections and long boarding processes required for larger aircraft like the A380.
Two wrongs don't make a right, but three lefts do.
commercial airlines have an accident rate of 0.06 crashes per million hours of flying whereas the Northrop Grumman Global Hawk UAV used by the US military has 1600 crashes per million hours of flying. This shows that the UAVs have a long way to go before we can trust our lives to this tecnology.
You're right, airplanes need to be more ecologicaly friendly. However, your statment that the energy cost for travel by flight is higher than for other transpor methods is not true. A Cesna airlpane can get between 15 and 30 miles to the gallon. A jet when you devide the the fuel consumption by the number of people being carried isn't bad either. They are similar in efficiency to the cars we drive. As for making hydrogen by nuclear means, why do people always bring up nuclear power. There is no safe way to dispose of the waste yet and this is unlikely to come anytime soon. Until then, it's just a time bomb until there are serious environmental issues from radioactive waste that leaks into our water supply.
When they were designing the SR-71, the Skunk Works had a hell of a time designing the life support systems for the pilot-- and that's just one guy in a space suit. At Mach 3, the heat generated by air friction is sufficient that if the cockpit air conditioning system fails, he's in deep shit. If you're reading this and you think in your lifetime you're going to see passengers flying in casual clothes more than three times faster than the SR-71, you'd better think again.
Even if it does become technically feasible, so few people will be able to afford it that it would be completely impractical to try to build a passenger transportation business around it.
~Philly
Remarkably bad math. Escape velocity is closer to Mach 25.
Oh, and flying upside down doesn't have a magical affect on whether or not you escape or not.
Eclipse Aviation of Albuquerque, New Mexico have produced a Air taxi capable of carring 5 people upto 1500 Km, but for this to be widely adopted 'free flight' must first exist. This allows piolts to plot there own jouneys, cutting distances and utlising more airspace. 'free flight' relies on each aircraft having it's own computer that allows aircraft to avoid each other. For more information see this weeks (13/12/03) New Scientist p28-33.
As an aerospace engineer, I'm always surprised about how many things we are supposed to achieve in the next so-many-years.
People, believe me: It is _not_ going to happen. Period.
Why not?
Well first of all, aerospace as an industry is extremely conservative. Despite it's high-tech image, the facts (and my experience) show differently. Look at the shape of aircrafts for example: Essentially unchanged since the 1930s. The fuselage-wing-tail concept is still the most popular, and all the research on blended wings, canards, double-fuselage, and other stuff people have made up, have not changed a thing (try to find the book by E. Torenbeek, you'll be amazed about how rich a phantasy some people have). That is because it simply is by far the most efficient concept: it's easy to stabilize, and you can put lots of people in it. Blended wings, for example, turn out to be too thin for people to fit in for, say, an aircraft for 100 people. Also, safety is easlier to achieve, and there's lots of room for cargo/luggage and fuel. Boeing's SST and Sonic Cruiser, and even the Concorde, did not fail without a reason. The A380, the "next generation aircraft", still has the same basic design as a DC-3 had 60 years ago. Another example is materials: Aluminum is still the primary construction material. It is _very_ slowly being replaced with composites and laminates (carbon, glass fibre/epoxy, GLARE). Aircraft manufactures can't sell an aircraft until it is absolutely proven that the new aircraft is safe and maintainable and has cheap Direct Operating Costs. So they all play safe and go with trusted concepts/materials. The A380 took about US$15_billion_ to develop. You don't go gable with such amounts. You play safe.
Then there's an economic reason. Profits for airliners are extremely low: 3-5% is not unusual. In fact, very few airlines have made a net profit over the past two decades. In the USA, airlines go bankrupt every 10 years, in Europe they would not survive without government support. Investing in airlines is high risk. This automatically means that investments in aircraft manufacturers is also quite risky. So actual research development of new technologies in the aerospace industry are very low, and usually government-sponsored, related to military applications, or conducted in universities or research institures. The "time to market" of any new technology in the aerospace industry has been estimated to be about 35 years.
This is already too long a story, I could go on for pages. But realy, this kind of views on the future just makes me laugh my pants off.
L.A city centre -> L.A airport : 50 mins
L.A. ->Tokyo : 30 mins
Tokyo airport -> Tokyo city centre: 1:20h
10 ?"Hello World" life was simple then
Before someone posts about how rockets are fuel-inefficient compared to other engines, I'd like to point out that it mostly depends on the cruise speed of the aircraft.
If the plane completes the flight in ten times less time than a conventional subsonic plane, then its engines are burning fuel for ten times less time as well.
Modern high-bypass turbofan engines have a specific fuel consumption (SFC) rate around 0.5 lb of fuel per lb of thrust per hour. Current liquid fuel rockets' SFC is around 10, and solid / hybrid rockets' SFC is around 5. But the concept of "pound of thrust" evolves with speed: for example, a reciprocating engine with a propeller will give you much more (approximately four times as much) pounds of thrust than the number of HP the engine develops, _at low speeds_. At 375 mph, you get one pound of thrust per HP. And beyond, you get much less. That's why high subsonic planes use turbofans and the slower planes still use propellers.
At supersonic speeds the fuel consumption per distance covered of a turbofan engine can grow as high as 3+, but that of a rocket engine does not grow with speed, so there's a given speed beyond which rockets are more efficient than turbofans.
Maybe we deserve this world ?
"HyperSoar's trajectory follows a skipping pattern. Passengers would feel 1.5 times the force of gravity at the bottom of each skip, and weightlessness out in space. The experience would be comparable to being on a swing, although HyperSoar's motion would be 100 times slower."
Anyone else thinking about investing their life savings into sick bag companies?
I could see UAVs being used for freight long before the public will accept it for holiday flights. Also the piolts are concerned with the collision avoidance abilites of UAVs. This may mean that in the next few years we may see plans for UAV only airports near our lager cities. For this to become anywhere near reality the problems of overcrowded airlanes and over worked air-traffic control staff, need to be resolved. For tis 'free flight' needs to be adopted, it allows piolts to plot their own flight plans and then when airborne onboard computers 'project' a 300km (30 sec)'bubble' around each aircraft, and automatically resolve incursions into the 'bubble'. This method allows more direct and efficent routes to be taken by aircraft and frees up large regions of currently unused airspace. Boeing is backing this move and is also taking an intrest in personal air transport. Yes, that means a flying car.
Actually, the energy cost for travel by flight is really no higher than for other transport methods. Consider a quick calculation:
A 747-400 has a range of about 8400 miles, and a fuel capacity of about 57,000 gallons. Multiply that by 410 seats, you get around 60 mpg per passenger. And Boeing's new 7E7 "Dreaminer" is touting much higher efficiency than any of their previous jets. Airbus is doing well too, with the new A380 and Rolls Royce Trent 900 engines. Fuel capacity of 82,000 gallons, range of 8000 miles, 555 seats. Thats around 55 mpg per passenger.
So those numbers are way better than the CAFE (Corporate Average Fuel Economy) standards in the US, currently 20.6 mpg I believe, not including the SUV's buzzing around the suburbs that aren't subject to those rules.
Hydrogen fuel cells would be great, but they're nowhere near production status for commercial transport flight.
There was a Golden Age of private aviation -- perhaps the mid 1960's, when a Piper or a Cessna was competitive with a luxury car. What has happened since then is that liability insurance has driven the light plane manufacturers into the ground and priced light planes out of the market.
We can all get mad at lawyers and call for tort reform and exemptions for plane manufacturers. But flying a light plane is a much riskier activity than driving a car, and the high liability insurance making planes really expensive is society's way of saying that we place a high value on human life, or at least on human life lost in transportation accidents, and the legal system coupled to the market system has perhaps made the correct decision in trying to get people to drive rather than fly themselves.
You mention the "steam gauges" and the need for a glass cockpit in a light plane. The "steam gauges" are there because they are simple and reliable -- and perhaps safer unless there is an enormous breakthrough in light plane avionics.
The engine controls are very primitive and manual: throttle, mixture control, and in some cases, propeller speed: not much more sophisticated than a lawn mower. If you have a turbo engine, you have manual control over boost pressure and have to follow rules for both advancing and retarding the throttle so as to not ruin the engine. In the 1980's there as some attempt at modernization: Porsche came out with an engine with electronic controls and "single-lever power control." But I don't know if this changed the general market trend that light plane manufacturers went out of business or went high-end (half-million dollar plus airplanes), and the only affordable planes are the ones stamped "Experimental" (i.e. I built it myself so I can't sue anybody).