Questions about turbos & turbines..mainly..building your own tiny turbine from a turbocharger.

[mAdD INDIAN]

After looking at this video, I really want to build a turbine powered bicycle.

Now after thinking of buying one such as this , I figure it could be possible to build one using a used turbocharger from a Volvo or something found in the junk yard.

Things we need to overcome:
1) powering the turbo to spin
2) finding a way to concentrate exit gases so it produces ample thrust
3) packaging to fit on a bicycle or small device

First the theories:
a) can a small turbo from a Volvo/Saab/Audi/etc.. provide enough thrust to move a 150lbs object?
b) Can a car battery, hooked up electric motor powering the turbo, spin the impeller fast enough to provide the required thrust?

My idea was to have a platform at the bottom of hte bicycle housing the battery. Then it would connect to a motor which powers the turbo which is attached on top of hte rear wheel (on those platform things to hold stuff). Now I figure we could put a cone-type metal plate over the exhaust of the turbo to allow the gases to concentrate on the cone and come out faster. For fun, we could wire fuel injectors to give a little fuel for afterburners

For braking (who needs brakes? ) we could have a plate behind the cone-shaped plate to deflect the air in the opposite direction, acting as air-brakes.

What ya'll think about this? Feasible?

 

[Mingon]

b) Can a car battery, hooked up electric motor powering the turbo, spin the impeller fast enough to provide the required thrust?

You would end being less efficient than the battery just powering the electric motor.

 

[Lynx516]

People have used turbos but not as you described. They use them for the blades a gas turbine and hence produce thrust

 

[drag]

I think somebody beat you to it

But seriously...

I don't think it would be too fun, do to the nature of a turbine you are not going to get any boost from it at low speeds and as it goes faster it will come on like gang busters. It will be a kinda all or nothing type of boost. I suppose you would have a hard time controlling it...

I've seen were people have made jets from used turbos

I assume of course that you will only use the battery to turn the turbine, the main thrust will come from burning fuel. A kinda afterburner, the battery will force air into the exhaust chamber were the combustion takes place, right? Otherwise the battery will never even come close to being able to produce the amount of energy needed to provide thrust.
`````````````// <----- fuel in
__/'''''''\_/''''//'''
___/\_ ```// <-----burning chamber````` flame going thisaway---------------------->
'''''''''''\/''' <---impeller
'''''\___/'''\___


During the 20-30's and stuff they were experimenting with piston engined powered jets so I know it is possible. (actually flew some prototypes)

I realy doubt though if you sceme of breaking with flaps will succede in anything other then burning you leg hairs off.

forced-air jets
a whole bunch of links

just don't blow yourself up...

 

[capybara]

here it is - this guy (from new zealand) built a jet engine using a car's
turbocharger this article

 

[Howard]

It would be easier to use axial turbines, but I guess whatever floats your boat... does.

 

[mAdD INDIAN]

thanks for the info and links guys!

Also wat is an axial turbine?

 

[Peter]

helloooooo ... turbos are auxiliary parasites, regaining energy from the otherwise wasted exhaust gas speed of the main engine. Using a separate engine to drive the turbo, and then use the turbo's output as the sole source of output, makes no sense.

So if you're going to have a battery and a motor anyway, then use those to propel your vehicle. Directly.

 

[Snooper]

If you want a small turbine, it would NOT be easier to use an axial system. Axial compressors and turbines are a lot more efficent and compact than centrifical designs IF you can keep the tip clearance small enough to minimize leakage. The clearance required scales almost directly with the lenght of the blade: shorter blade, less clearance. With a small turbine, it gets VERY hard to keep the leakage undercontrol. You will almost never see a production turbine with a diameter of less than a foot due to that little problem.

A turbo has a properly design compressor and turbine. You only need to design the combustion chamber (lots of books in the college library cover this) and fuel control system. It won't be fuel efficent or quiet, but it will work. And be a heck of a lot of fun in the process!

 

[mAdD INDIAN]

Originally posted by: Peter
helloooooo ... turbos are auxiliary parasites, regaining energy from the otherwise wasted exhaust gas speed of the main engine. Using a separate engine to drive the turbo, and then use the turbo's output as the sole source of output, makes no sense.

So if you're going to have a battery and a motor anyway, then use those to propel your vehicle. Directly.

Yeah I realized that now.

 

[WhiteKnight77]

As an old jet engine mechanic (T58-GE-16), a cars turbo would need lots of work to add a combustion chamber and power turbine section to it in order to work properly. You would need to add a continuous flow fuel injector(s) and an igniter along with a souce of power for the igniter. Next question is what kind of fuel (jet fuel may be hard to come by for a private individual and JP8 might be rather expensive) would you be using?

This is all doable, just needs to be thought through thoroughly.

 

[Snooper]

It's not quite as much work as you think WhiteKnight. I car turbo already has a matched compressor and turbine (along with a connecting shaft and bearings and supports) all in a balanced assemble. You really only need the combustion chamber. Building a continous flow injector isn't that hard (given you have access to a machine shop or friends that do). The ignitor is easy: same thing they use on a full size jet, the spark plug. There are tons of very simple circuits that will convert 12V into a spark through a standard automobile coil.

The fuel isn't that big an issue either. Jet engines will run on a wide variety of fuesl: Jet A, the assorted # jet fuels, deisel, heating oil, kerosene, parphine, vegatable oil, gasoline, propane, natural gas, etc. Needless to say, you won't run a commercial jet on vegatable oil, but that doesn't mean it won't run just fine. Jet fuel does burn a lot cleaner, but for a backyard jet, there are plenty of fuels avalable. Propane would be a fantastic fuel as it will atomize itself so you don't have to waste as much time trying to build an impingment injector and it burns very, very clean.

Not sure I would want even TRY to fly an ultra light powered by one of these Frankenstiens, but I sure would like to fire one up to play with it on the ground.