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In the mid sixties an American car company experimented with a turbine powered car that proved to be an excellent idea with bad timing. They could not make the car small enough to fill the engine compartment, though perhaps by American car standards of this era it was only about regular size now. The
engine used less parts, and ran on anything; petrol, diesel, corn oil, scotch, etc. The car failed because the metals of the time could not withstand the heat that built up. Why not scale the engine down and use it on a Vespa? I know that engineering which does not look to steel for everything could solve the heat problem. Because turbines spin at constant speed, one hand would control the clutch, and the other would control the brake. The whole package would be lighter with less moving parts. I also believe that watery Postum could make a very good fuel. As far as safety goes...well don't drive a Vespa if one is truly concerned, but the probability of the engine spewing turbine blades everywhere in a crash is very little.
Micro turbines
http://www.m-dot.com/page8.html
About this size? [AO, Oct 04 2004]
The Batcycle...
http://www.geocitie...1966/66batcycle.htm
Nuts, no turbine here... [RayfordSteele, Oct 04 2004]
*baked*
http://www.marineturbine.com/
turbine motorcycle [thejini, Oct 04 2004]
[link]
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Instead of using a clutch, you could equip the thing with a continuously variable transmission. |
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You wouldn't even need a CVT. If you make it a free turbine (like the Allison PT6), just hook the power turbine directly to the drive shaft, and use a set of variable stator vanes to control the output from zero torque all the way through max output by moving a single lever. |
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Not to be cornfused with the turbin bike, a favorite mode of transportation during the hajj. |
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I always thought turbine engines operated best at high continuous revs ( full throtle all the time), and this is why they weren't practical for cars, since many cars/ motor bikes are used in stop and go traffic. |
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I do think it would be a good idea for transport trucks and trains. |
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How well does a turbine work if you run it at constant speed and change the load to accommodate the varying speed of the vehicle? |
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There is a turbine bike in Jay Leno's collection. Turbines are used in some european trucks to power generators and charge batteries. The turbine is run at an efficient speed, while the batteries power electric motors at the wheels. If you have to vary power all the time, the turbine will still be efficient, but it won't last too long before it succumbs to thermal cycle fatigue (hot/cold/hot/cold...). |
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The problem with gas turbine engines, even with a CVT or with variable geometry power turbines, is that the POWER output required from an engine varies, and it takes a turbine a long time to spin up or down to change the amount of power output. Jay Leno's turbine bike, for example, starts accelerating a second or two after you give it gas. That was also drivers' biggest complain with Chrysler's turbinecar (after poor gas mileage, which is related). There IS a solution to the problem, though: A series hybrid. Most hybrids nowadays are parallel hybrids, but a series arrangement is simple: Turbine->generator->ultracapacitors->motors->wheels. With this arrangement, the ultracapacitors/batteries power the motors while the turbine is spooling up, solving the turbo lag problem. This solution however does bring with it another problem: weight. All these motors and generators may outweigh the benefits gained from using an ultra-lightweight gas turbine. |
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[AO] I like the micro turbin link. I wonder if such a turbin could replace the heavy lead acid battery in a car. First start the turbin using a real small Lithium battry or a gold capacitor. Then start the main engine from the turbin. |
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What Freefall and TerranFury said. Train engines have been using a diesel->generator->motor system for decades, and it seems to work just fine. |
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Rover built test Turbine engines for vehicle aplications in the 60's or 70's have a pile of test data from one somewhere as the uni i wnet to had one of the engines |
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[thejini]'s link: Wow, 227 mph on a motorcycle. Don't sit up straight. |
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<pedant> fewer parts not "less
parts" </pedant> Rule: Use
fewer to describe countable
things. Use less to describe
uncountable quantities, collective
amounts, and degree. These
terms are not interchangeable. |
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I liked the Micro turbines link. Maybe you could have a turbine powered scooter if it used a turbine/generator/electric motor drive system. |
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The problem with turbines, is that to really get them running efficiently you have to be in a ozone rich atmoshere. Hence the reason aircraft really like to use them. Now if you put the "ionizing intake air for better performance" post refrence infront of the turbine you might get somewhere and forget direct drive like the trucks work with, use the k.i.s.s. method! use the engine's thrust. |
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Where'd you hear about that, Elnyne? I'm a little skeptical... |
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The turbine/generator/electric motor method works, but not in an enviroment where weight is not a cheif concern. look at the machines that use it, ie large dump trucks, trains, tanks. Generators and electric motors are just plain heavy. The CVT or a fluid drive transmission would work if you kept the turbine spooling constant at it's peak efficancy, which would change the faster you went. Basically having the engine one step ahead of the transmission all of the time would eliminate the turbo lag. Example: sitting still or at idle, the turbine spinning freely at say 45,000 rpm, you twist the throttle which only controls the fluid flow through the transmission, as you accelerate the engine spools relative to speed, the excess pressure created in the transmission from the increase in engine rpm is bled off, giving a "reserve" when sudden throttle is needed. When you need to slow down fast, let off the throttle, the bypass valve is opened and the impeller in the transmission acts as compression hold back. The turbine still lags but it's okay since it's not directly linked to the rear wheel. Am I making any sence? |
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I wonder though, wouldn't a turbine have horendous fuel mileage compared to a 50-60+ mpg vespa? Dunno just thinking, |
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I think you mean "...but only in an environment where weight is not a chief concern." |
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yep, your right, poor grammar is my monster. Thanks for the correction. |
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