old git

I just took a look at the Feb 24 2007 issue of New Scientist. This is a Brit science weekly, it poses the question "Can maverick technologies turn aviation into an eco success." What followed was a number of flying wing, lifting body, laminar flow control measures and "open rotor engines" (props). It doesn't seem very different from what I was looking at in the 1950s.

One sentence particularly took my eye, "A single flight across the atlantic (by jetliner) can guzzle about 60,000 litres - more fuel than the average motorist uses in 50yrs of driving - generating around 140 tonnes of carbon dioxide." (nearly as long as I have been driving!)

I found it interesting, if a bit disturbing. It worries me, where the "No Smoking" brigade will turn their attention when all the Marlboro men are gone?

Just as a point of interest, I seem to remember that there was long drawn out litigation over a lifting body aircraft designer and Pan Am. The designer successfully built and flew the aircraft. It had three engines and carried numerous passengers, not one of those delightful experimantal lightplanes. Sorry, but my failing memory doesn't get me any futher.




old git - - - - - - - aka John L.

crasherboy

Where will they turn their attention after they nail everyone else? Model airplanes of course,claiming model engines are screwing up the air quality [maybe your wood stove or oil heater if you heat that way]. Seeing they have nothing more to do they might get bored with sitting around!

HighPlains

My Feedback: (1)

What's that, maybe 40 gallons of fuel per passenger for a 3,000 mile trip. Beats hell out of taking a boat and producing the food to feed them for 10 days.

Jim Thomerson

I saw part of a program on TV about steps American Airlines had taken to cut fuel costs and make more money. The three I remember are: (1) no more magazines except the AA magazine. The AA magazine has to generate enough revenue to pay for itself and the fuel needed to transport it. Savings of a small number of million dollars a year. (2) Carrying less water for the toilets, cutting from something like 90 gallons per flight to 70. Saving a slightly larger number of million dollars a year. (3) Monitoring fuel fillups so that excess fuel is not put onboard. Saving of large number of millions of dollars. There were several other things I don't recall.

The smaller the carbon footprint an airliner has, the more money it makes.

B.L.E.

Exactly what I was thinking! If all the passengers rode motorcycles for 3000 miles, they would collectively use a lot more fuel than that airliner does.

Fuel economy = profit for airlines so there is no need for government intervention. I foresee a continuing set of incremental improvements, not some radical design change. More efficient engines, lighter composite materials, etc. Compare a modern car to the old clunkers we drove in the 1960's. They are radically better in every way, but, it came about from the cumulative effect of a series of incremental improvements, not from some revolutionary discovery.

In spite of all the hyperbole about the advantages of canards, flying wings, and lifting bodies, the fact that most all competition RC sailplanes are conventional wing, fusilage, and rear stabilizer designs tells a lot about just how terrible the conventional airplane is not.

old git

I found the contentious aircraft again using google, it's the Burnelli. I wanted to be contentious but I do rather like the look of the early Burnelli, maybe the later variants could be an improvement on the modern trend. Sorry but I am having a picture download failure so I cannot show it.

I agree that many changes of aircraft design have been the result of incremental change but the jet engine and use of composites surely are a step change. As to our old clunkers, I drove a Triumph M/cycle and there were parts from 1938 models that fitted those built in the 1970s. It was the Japanese that made a step change in design. My first car was a 1934 Eustace Watkins Wolsey Hornet. The engine was the size of a 3.4 Jaguar, six cylinders with overhead cam but a swept volume of only 1200cc. It had also a separate chassis and drum brakes. These added up to an interesting and good looking clunker. Modern cars have a monocoque/integral body chasis and are full of significant improvements, not just small refinements.

I hope we have more significant improvements to come; such as the 2.3gig radio gear!




old git - - - - - - - - aka John L.

HighPlains

My Feedback: (1)

Plenty of idiotic statements like this on the Burnelli web site.

There is a principle reason that passenger airplanes look the way they do. The pressure vessel that they enclose the people within so that they might breathe. Easy to do with a tube, not so easy in a box. Huge difference in weight.

da Rock

Other reasons equally as important to airlines..... People move around in an airliner. Flying wings do not like randomly changing CGs. People also are more comfortable sitting near a window. Very few windows beside passengers in a flying wing. Airports have very restricted ramp space between gates. Pulling a long tube full of people up to a gate is quite a lot easier than turning the tube sideways, sticking wingtips on the sideways tube and then taxiing it up to the gate.

There is way more to designing a passenger airplane than just choosing whatever aircraft layout/design suits your latest whim.

B.L.E.

Replacing piston engines with turbines was indeed a revolutionary step in aircraft. The great turbine hope never materialized for cars. It was not just turbine lag, but also the fact that turbine thermodynamic efficiency dropped off dramatically when throttled down, and cars spend a lot of time with their engines putting out less than 15 horsepower.

Monocoque bodys are at least as old as air cooled Volkswagon beetles and fuel injection was around in the 1950's. It was not until the micro-processer was invented that fuel injection eclipsed carburettors. Old 1930's cars used four stroke piston engines with poppet valves opened by cams and closed by coil springs. They rolled on rubber tires inflated with air. They had transmissions that used gears and clutches. They had hydraulic brakes. Really, it's mostly refinement. It's hard to pinpoint the exact time period when the automobile suddenly became modern.
Even electric cars were around since the earliest days of the automobile.

B.L.E.

OOPs, double post[:@]

rmh

My own thots on aerodynamics of aircraft---has far more to do with the structural needs and power limitations .
IF--just -IF-- we could somehow have available -- power plants with double the power outputs at half the weights and airframes with double the strength at half the weights -- imagine what the results would look like .
The airfoils some drone on about endlessly - would have much less effect for many of the general av type craft. supersonic stuff would not be much different tho -as I see it .

B.L.E.

I also don't forsee supersonic airliners any time soon, even if it is feasable to build one. The reason is that it just isn't worth it given the high costs of going that fast. Ask the average Joe why he doesn't visit Europe more often and you will probably hear that it costs too much, not because a sub-sonic Boeing 747 takes so darn long to make the trip.

banktoturn

I don't think commercial airliners are power-limited. For all but the very
largest, more powerful engines are available, but not needed. Structural
advancements are and would be welcome, of course, as the structures are
subject to demanding loads, and weight reduction has big benefits.

As for the airfoils becoming less important under the conditions you describe,
I think the opposite is more likely. There are two main categories of drag:
lift-induced drag, and 'parasite' drag. If the weight of the aircraft were reduced,
the lift-induced drag would also be reduced. The airfoil has nothing to do
with lift-induced drag, but is indeed important for 'parasite' drag. With less
lift-induced drag, the drag reductions possible through airfoil selection would
become more important, not less important.


banktoturn