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Propeller vs Direct drive
Off the wall question;
What is the difference in efficiency between propulsion from a propeller vs a direct traction drive (wheels, including drivetrain losses)? My research lead me to some odd vehicles, and more questions as usual. http://i.kinja-img.com/gawker-media/...c10kqfhjpg.jpg http://i.kinja-img.com/gawker-media/...ha1ou1bjpg.jpg http://i.kinja-img.com/gawker-media/...o2hnwkojpg.jpg http://i.kinja-img.com/gawker-media/...a05nnvejpg.jpg |
True, I'm thinking around 45-70% of direct depending on pitch. Not sure though.
Using ηp=T∗u/Pshaft A bad amount for mpg. The project places too much priority on weight though. http://hizone.info/data/2005/09/08/images/03.jpg http://i.kinja-img.com/gawker-media/...csnvbyljpg.jpg http://lh4.googleusercontent.com/-VJ...4/s900/p12.jpg http://www.curbsideclassic.com/wp-co...wagen-prop.jpg http://lh4.googleusercontent.com/-X4...-4/s900/p5.jpg http://lh3.googleusercontent.com/-MZ...U/s900/p20.jpg Lotus http://www.wired.com/images_blogs/au...otus_ice05.jpg http://db2.stb.s-msn.com/i/C4/C3E0EF...A9F145A7C8.jpg http://blog.modernmechanix.com/mags/..._drive_car.jpg http://www.team-bhp.com/forum/attach..._propeller.jpg http://blog.modernmechanix.com/mags/...p_tricycle.jpg http://blog.modernmechanix.com/mags/...ed_fan_car.jpg https://www.youtube.com/watch?v=xRV7RmTk2yA http://riordanco.com/jimsblog/wp-con...cycle02jpg.jpg http://riordanco.com/jimsblog/wp-con...ropcycle01.jpg http://www.sonicwind.com/image/aeroliner-1.jpg http://www.sonicwind.com/image/dragprop.JPG https://www.youtube.com/watch?v=4LJuGftUFbI http://www.petersen.org/uploads/imag...Driven-Car.jpg http://www.strangecosmos.com/images/content/144192.jpg More fun http://www.treehugger.com/bikes/the-...ith-video.html http://media.treehugger.com/assets/i.../prop-bike.jpg |
Screw the cars, now an air train, thats front page news. :thumbup: Trains doesnt have much traction, thats why they are soo efficient. They use sand to air in starting off and braking as traction is soo limited due to what little contact all that weight makes with the rails and wheels.
http://gajitz.com/wp-content/uploads...er-train-1.jpg |
I don't see it coming to a mass-production car, maybe a turbine-propelled one would make more sense nowadays.
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Is there any gyroscopic effect?
As for efficiency, I expect it's much less efficient than a direct drive in stop and start driving, and I wonder what it would be like to drive behind a propellor driven vehicle in traffic! |
With enough back wind a propeller is better.
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From what I remember about propellers, I think it was around 59% energy transfer before it was easier for the air to move around the propeller.
The big advantage is not relying on the wheels for traction, like has been stated, and in the old magazine clippings that is what was stated as well, ideal for low traction areas like mud, grass, ice. When I've driven an air boat, that is a boat with a flat bottom and a large prop in the back, it was very much a fluid drive, like driving a vehicle with a very loose automatic transmission. |
It would at least discourage tailgating :-)
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Then you take your propeller driven car to a restaurant on a sunny warm autumn day.
You find a vacated but narrow parking slot under the trees close to the tables where people dine. It takes some manoevring back and forth to fit nicely in that slot. You'd better leave a big tip. |
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