Smallest turbine ? - RC Groups
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May 21, 2007, 12:24 PM
AustinTatious
AustinTatious's Avatar
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Smallest turbine ?


Coudl anyone provide links to the smallest gas turbine ever made ?

I seem to recall seeing a 1 inch diameter someone was working on but I never saw any follow up.

HOw small COULD you make a turbine ?
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May 21, 2007, 03:19 PM
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The smallest one which is available commercially is Martin Lambert's Kolibri. www.lambert-modellturbinen.de/html/english.html

One or two people have made homebuilt engines about the same size as the Kolibri but I don't know of anything much smaller which has actually been run. It is very difficult to build and balance something as tiny as that - the Kolibri does over 240,000 rpm.

Various people have shown tiny turbines over the years, and there are all sorts of rumours about the military building ones which are only half-an-inch long, but I don't know of anyone who has seen anything smaller than the Kolibri that actually works. It is comparatively easy to make something that looks like a small turbine and to colour the tailcone by heating it, making it look as if it has been run, but unless an engine is seen working in public it's not a turbine, only a shelf ornament.

Sara Parish
Wren Turbines
Mar 12, 2008, 09:15 PM
Moderador.
Alfredo Rubio's Avatar
WOW!!!! as a micro planes lover this is great
Mar 31, 2008, 12:57 PM
Andres Gtz.
i think is the best idea for replace at edf in the park jets.

look

Twin Jet mit Kolibri (2 min 8 sec)
Apr 22, 2008, 02:02 PM
Registered User
Here is the smallest one....
Apr 28, 2008, 01:54 PM
Registered User
WOW! That's small! Any more details on this Bryan?
May 07, 2008, 10:45 PM
Registered User
Not much.
I heard it was a Darpa project, and it turns 600,000 rpm on air bearings. But I cant find any confirmation of this. I also cant find any pics of it in the casing, or running.
May 08, 2008, 12:51 AM
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Speed is Life's Avatar
Sweet! Turbine powered Gold Finch..............
May 23, 2008, 02:52 PM
Registered User
The smallest I've heard of are mems-scale turbines (millimeter size and smaller). They're being used as generators though, not for thrusting. Maybe one could make some sort of fuel-electric hybrid aircraft
May 24, 2008, 07:02 PM
Registered User
guys the smalles turbine is much (!!!) smaller and from MIT gas turbine laboratory.
Quote:
The micro-gas turbine is a 2 cm diameter by 3 mm thick Si
or SiC heat engine designed to produce about 10 W of electric
power or 0.1 N of thrust (!!)
its really 3mm thick, including compresser, combustion, turbine wheel, electronics, etc.

look at this site and photo on right side of the page:
http://web.mit.edu/newsoffice/2006/microengines.html
Oct 15, 2009, 04:12 AM
Plane crazy
Tartago's Avatar
You can get a cheaper one (~1500usd) from jetjoe.com, it is called Jet Joe jr.

http://www.jetjoe.com/main.php

Nice to see one on a Su-30M!!
Oct 15, 2009, 06:29 AM
The wheels touch down FIRST??
BJ64's Avatar
Just LOVE the colour co-ordinated matching gas bottle there A G G.

And the fact that you start her with the turbine facing the inside of the back of the car

Just hope it don't flood and fart a huge plume of wet burning Kero there one day .... Frazzled seat-covers if it does...

BJ

PS - wonder what the insurance company would say.... LoL
Oct 15, 2009, 06:55 AM
The wheels touch down FIRST??
BJ64's Avatar
Regarding the smallest working Turbine - there must be a finite cut-off limit to the mechanics and fluid-dynamics of air itself and being able to deliver and vaporize the Kero (assuming that we are talking 'Jet' as in paraffin-burner). And, of course, to be able monitor and supply the correct amount of oxygen to efficiently burn the micro-vapour of fuel being supplied.

I would think that once you go a certain tiny size, you'd only be able to run the thing on Propane or a similar gas, where the relatively huge viscosity of a 'heavy-oil' fuel would be just to 'thick' to be able to atomise and regulate accurately through the injectors.

The enormous RPM would require extremely accurate bearings etc, I would assume - the tolerances once you go really small would be so tight that any bearing slop or end-float would be critical to avoid catastrophic failure of the extremely fast moving parts, not to mention drastically altering the air/fuel flow though the turbine. A thousandth of an inch either way is probably something like a 30% shift in efficiency. Maybe even the difference the difference between a start, and a no-go.

Some of the 'micros' out there that actually run are already pushing the boundaries.

How much smaller can we realistically go - until shear Physics takes over and says "Nup - can't go no smaller" ??


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