# Boundary layer turbine (Tesla turbine) propulsion

One of the major weak spots with multi-rotors is the exposed propeller blades, they break and they hurt things.

I know people have designed guards and experimented with ducted fans, but has anyone done work with a boundary layer turbine arrangement? I've been kicking this idea around in the back of my head for some time now and just recently saw a ceiling fan project that uses this effect.

I always imagined a nested conical frustum stack (imagine lamp shades stacked on top of one another with a small gap between each). As the assembly spins, air is accelerated from the center down and out at an acute angle relative to the vertical axis, whereas the above ceiling fan example moves the air perpendicular to the rotation axis. I know it will blow air, but will it move enough to provide any useful thrust?

Any thoughts?

Now if I could just get a hold of some graphene and aerogel lampshades to experiment with...

Views: 1985

Comment by Mathew krawczun on November 16, 2012 at 1:28am

short answer would be no I'm afraid.

a tesla trubine like this works by slinging the attached boundary layer off like a slingshot so any motion not perpendicular to the axis because really inefficient. and thrust would seem to be another bust as well seeing as the tesla trubines are bad at making pressure. a TT makes a good light, cheap and easy to make generator but not so much a prop.

but that just my two cents testing an idea is always the best bet.

Comment by Dave C on November 16, 2012 at 2:07am

Yup, there are these too, http://www.firebox.com/product/4910/Dyson-Air-Multiplier-Fan?aff=11...

I'd love to ramp the power up on 4 of these, but i still don't thing it would be anywhere close to flying. I'm off to town today, if i find one in a department store I will check it out!

3D Robotics
Comment by Joshua Ott on November 16, 2012 at 8:04am

Mathew,

I understand what you're saying about centrifugal force acting perpendicular to the axis of rotation. Perhaps a deflector around the perimeter would be the way to go, if this was segmented it could be used as a control surface. I need to dig in deeper.

Dave,

I think the Dyson fan is using the Coanda effect? I'll have to check it out again.

Thanks for the response guys : )

Developer
Comment by R_Lefebvre on November 16, 2012 at 8:27am

Dave, I'm pretty sure those Dyson fans are bunk (like the rest of their stuff).  I don't think those fans are more efficient than a normal fan by any stretch.  They're really not even quieter.

Comment by Dave C on November 16, 2012 at 9:05am

Yes, I'm pretty sure its cockadoo too, just like their vacuum cleaners!

You'd probably have to power with with 3-phase 11,000V though :)

Comment by Dave C on November 16, 2012 at 9:08am

It's looks like Jean-Louis has beat us too it again  :)

http://diydrones.com/profiles/blogs/coanda-effect-saucer-ces-uav

Comment by Dave C on November 16, 2012 at 9:21am

And now having read that thread I'm going to build one - a big one, with flashing lights :D

3D Robotics
Comment by Joshua Ott on November 16, 2012 at 9:32am
The Dyson products may not work any better, but at least they are over-priced!

Developer
Comment by R_Lefebvre on November 16, 2012 at 9:56am

With lots of shiny plastic, and whiz-bang-futurismo styling!

Comment by Scott Berfield on November 16, 2012 at 12:01pm

That saucer thing is awesome.

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