Soon, we'll be seeing things like composting toilets.
Posted on 06/06/2006 7:13:58 PM PDT by SandRat
Suppose its cheaper to buy oil from Muslim countries, but the option is spending a more money on domestic solutions that use less oil, but cost more.
Is there any condition that your "sound economic practice" could support this?
That slower flight time also means that airlines will lose that plane's availability while it's still in the air instead of being turned around for the next flight. Instead of five flights a day the airline may only be able to squeeze in four flights.
When you're paying $100 ~ $150 million for an airliner, you want to make as many flights a day as possible.
"Wel then, we might as well close the patent office because everything that could possibily be invented has already been invented.............. "
As far as what those designs show there isn't anything there that if they were patented the patents would have expired a long time ago.
Boeing finds Dick Rutan?
Most commercial jet engines today are High Bypass variety where 80% or so of the thrust comes from the fan, and not the jet portion of the engine. The UHB was just the next logical progression. Get rid of the fan shroud which is restrictive and is installed only to control noise. But that was the big hang up, however. They are much louder than conventional turbofans, and could not meet the rather strict, in many cases, airport noise ordinances in most communities.
So we continue to pollute more so people who buy houses around airports and still hear the crickets chirp.
Ain't government wonderful?
Yes, UDF (Un-Ducted Fan) was another acronym for them as well.
Actually, they aren't THAT bad.
The EPA says only 2% of the NOx from mobile sources comes from Aircraft engines. Most of the air going through a turbine engine is just air. Only 8% is products of combustion and only .4% is "pollution". Large Turbofans have a compression ratio higher than a Diesel so there isn't much left to come out but soot and the impurities in the fuel/air, which aren't much.
The "typical jetliner" is also 20 years old. Compare a typical Jetliner to 1,000 or even 100, 20 year old cars and the jetliner is cleaner.
If you had said "particulates", you might have a point as most older jets emit tons of these, but they don't really have much to do with smog. Until the EPA cracked down on Diesels in 1997, trucks and trains emitted tons of this stuff, too. These older planes will go the way of the dinosaur over the next 15-20 years and the particulate problem (if there ever really was one) will go away, with them.
As for efficency, the AVERAGE revenue passenger miles for the US airlines is 44 mpg. I would guess LA traffic averages less than 20 revenue passenger mpg.
However, thanks to better gearbox designs since then (which allow the switch to ten-bladed propfans), this will allow for slower fan speeds with far less noise and less danger in case of blade failure. The Fozzie concept could actually work for an airline like Southwest Airlines flying routes under 900 nautical miles in length, where cruise speed performance is less critical. For example, this plane would be perfect for Southwest's intra-California routes and routes between California and Nevada/Arizona; another place such a plane would be useful is intra-Texas routes.
Example: Delta wings SUCK at low speed. Current commercial wing design is a compromise between straight wing (excellent lift, high drag, and poor high speed performance), and a fully swept, or delta wing (low drag, great high speed performance, lousy low speed performance requiring much higher take-off and landing speed)
Now you mixing Turbo-Prop (With gear box), with Turbo-Fan's (No gearbox) The "Open Rotor" UHB, or UDF is a derivative of the Turbo-Fan. No Gearbox involved.
It certainly is an inappropriate name for a "quiet" design.
Soon, we'll be seeing things like composting toilets.
If you spin the prop slower, the plane is going to go slower, which is unacceptable.
As Jesse says, Keep hope alive.
Me, being a realist, know that the UDF is dead. To prove my point, here is the the GE UDF test bed aircraft crashed for a movie prop. No Air and Space Museum for it. After the first flight, everyone pretty much knew it had no future.
I personally think it sounds cool (and if there were only a couple of them, I wouldn't mind), but it aint 1944 anymore.
One of the reasons why the ATR-42/72 turboprop airliners switched from four-blade propeller units to six-blade propeller units was the very fact this allows for slower fan blade speeds for the same thrust output, which 1) reduces noise quite a bit and 2) reduces fuel burn due to slower speed of the engine during flight. Why do you think Lockheed did the same thing with the C-130J, the current model of the famous Hercules cargo transport?
Hence the reason why the switch from eight-blade to ten-blade propfans. With more blades, this allows for slower blade spin speeds with all the benefits I mentioned above.
The Fozzie is a total joke of a design.
Apples and Oranges.
If you put on more blades and spun the prop slower, you may be quieter, but you also aren't going 450 mph anymore.
but where is the Animal design?
ANIMAL!
Nice designs, but I hate the Muppet names.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.