RE: [TeslaTurbine] Re: Tiny Turbine
- Hmmm hadn't thought of that.
I was considering salvaged hard disks... any thoughts...
From: William Carr [mailto:Jkirk3279@...]
Sent: Tuesday, March 22, 2005 9:02 PM
Subject: [TeslaTurbine] Re: Tiny Turbine
On Mar 22, 2005, at 3:35 PM, TeslaTurbine@yahoogroups.com wrote:
> To All
> I added some photo's of my 2.5" turbine. If anyone cares to look
> there in the tiny turbine album.
> Here's what I've learned. First these little motors suck alot of
> air. I have a six gallon tank, and I only got about 30 seconds of run
> time before it was spent. Next disc spacing is extremly extremly
> important. Due to convienience I built this turbine with .015 to .02
> clearance, but I think about .005 would be optimal. Well thats about
> it. Hollar at me if you want to know anymore
Let's flesh out the details. You're using a six gallon air tank to
get motive power out of a small turbine.
Your disk spacing is 0.015 inches.
According to the old article interviewing Tesla himself, the clearance
for air should be closer to 0.01inches. The clearance for water is a
I looked at the pictures you posted.
I don't see any air slots near the hub.
A TT used for motive power needs air to enter via a nozzle in the side
of the case and exit from a vent near the hub. And each disk needs
slots in it to allow air near the hub to flow between the disks.
A TT used to BLOW air needs air to enter through the vent at the hub,
pass through the slots in the disks, and exit via the valve in the side
of the case.
Imagine what would happen if you used five disks, with no hub slots.
The disks spin, the air or working fluid is drawn along with the
spinning disks and thrown outward via centrifigal force.
Now, this causes a vacuum to develop at the center hub. If there are
no slots in the disks, then there'd be no way for more air to enter the
system. The air flow stops. Efficiency of the system falls.
But if there ARE slots in the disks, outside air can be sucked through
those hub slots and thus blown outward. A vacuum still develops of
course. It draws a constant airflow through those hub slots. The
system is thus more efficient.
Of course, if you make a TT with only one disk, you don't need slots.
My own TT project is still on the drawing board, but the pilot project
will be made from AOL CD's. They're flat, designed to spin without
wobbling, and free.
The second project, designed to be heat resistant, may be made from 3"
cutoff wheels with 3/8 inch center holes.
The idea of the cutoff wheels is that they're extremely fire resistant,
designed to run at very high speeds without wobbling, and hey, they're
cheap. Machined brass disks flat enough might be salty.
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- I was also considering salvaged platters from disk drives,
the 5.25" variety actually.
Except I was going to drive them with a high speed motor
and A) get compressed air for an air brush, or B) use it
as a vacuum pump, depending on airline arrangements.
I'm still in the parts-gathering stage, I have sufficient
platters for a start but I'll want more.
I figured one of the $10 trim routers from eBay would run
things at 30,000 RPM for short term, then the motor would
burn out. If the 5K rated disks didn't explode first.
Obviously, a sturdy enclosure with a good scattershield
is called for. Or maybe instead, use a washing machine
motor and gear things up less dramatically with a series
Any thoughts on the design?
I would love to hear thoughts and where possible, specs
on extant turbines this size.