Introduction: Convection Powered, Counter Rotating, Kinetic Sculpture

Picture of Convection Powered, Counter Rotating, Kinetic Sculpture

Powered by Sterno made of wood, sounds like a recipe for fire. It took two cans of heat to get it moving the first time but continued to spin almost as fast after removing one can. It serves no purpose yet but tomorow I'm going to add a pot- pouri jar just under the rotor blades to give it
 reason for being. I'll call it counter rotating pot-pouri diffuser.
I'm working on downloading a driver for my video cam so you can see it in action.


Step 2:

Step 3:

Picture of

Materials used:
1/4" x 5.5" x 48" poplar
.037" x 12" x 24" birch plywood
1/2" x 5.5" x 24" poplar
1- 4" long shawl pin
4- 1/8" plastic beads
Titebond III wood glue
1- Corel saucer

Tools used:
Epilog laser (other methods of cutting are possible)
cordless drill
small paint brush
small vise grips
small spring clamps
small square



Step 4: Assembling the Rotor Rims

Picture of Assembling the Rotor Rims

I built a jig to assemble the rotor rims using a very flat support board, a 1/8" thick plywood circle the inside diameter of the rotor's 1/8" plywood rings. Made a clamp from 1/8" plywood to hold the .037" thick birch plywood to the 1/8" rings. When gluing up everything stay flat and tight. Very little pressure is needed on the visegrips to hold the .037 " plywood tight.

Step 5: Mirror Image the Rotor Blades

Picture of Mirror Image the Rotor Blades

Notice the small tabs on the rotors (tips of pencils), the rotor hubs need to be glued so the rotors are mirrored.

Step 6: Assemling the Rotor Hubs

Picture of Assemling the Rotor Hubs

I drilled a hole into my build table ( square with the surface) so the hubs would glue up square.

Step 7: Assembling Rotor Blades to the Rims

Picture of Assembling Rotor Blades to the Rims

The rotor blades are quit thin and very flexible. To assemble them I simply twisted each blade to lock the two tabs onto the 1/8" plywood ring, one tab over the ring, one tab under. I mirror imaged the rotor blades so they would spin in opposite directions. Tension holds them in place, no glue is needed.

Step 8: Assembling Main Support Body

Picture of Assembling Main Support Body

I attatched the support body halves to my build table so when I glued up the ribs and stringers they would remain straight.

Step 9: Adding the Ribs

Picture of Adding the Ribs

Gluing on the ribs I used a square to insure they wre too.
note: if you cut with a laser the glue faces need to be sanded square.

Step 10: Installing Rotor Axle to Main Support

Picture of Installing Rotor Axle to Main Support

I used a small pair of vise grips to support the axle and rotor assembly while the JB WELD cured. 

Step 11: Finishing

Picture of Finishing

Finish by gluing the support to the base and fit the saucer to hold the Sterno can.


randomray (author)2010-12-05

Hmmm , I wonder about using bicycle wheels for this . I really like your support structure , way cool looking .

PDRWLSN (author)randomray2010-12-05

Bicycle rims would surely work if you used enough heat to overcome the weight.

randomray (author)PDRWLSN2010-12-05

Oops , I was thinking about the bearings , good point about the weight . There is a project an Aussie inventor came up that works on this principal using solar heat in the out back only on a truly massive scale .

Foxtrot70 (author)randomray2012-02-12

Do you have a web site where the Aussie inventor has info on his project? Sounds very interesting.

randomray (author)Foxtrot702012-02-12

Here's a starting place ,

hammer9876 (author)2010-12-05

Call me curious, but will a candle power this? I can imagine that a scented candle burning under this thing could disburse the scent very nicely.

Congratulations on being featured.

PDRWLSN (author)hammer98762010-12-05

Thank you, In it's present state a single candle will not provide enough heat. Scaled down to lighten the rotors and bring them closer to the heat scource, quite possibly.

kwazai (author)PDRWLSN2011-11-10

Because of the nature of bouyancy, if the turbine were more like a drag turbine design (sail shaped sort of) and overlapped foils ever so slightly (12% or so) it might run off a candle. With the low velocity laminar flow coming from a candle it would need be impact driven rather than lift driven. just a thought.

McGyver2 (author)2011-01-05

Were is the water in this? Convection has to do with the transfer of heat in water.

PDRWLSN (author)McGyver22011-01-05

According to American Hertitage Dictionary:
1. The act of conveying; transmission.
2. Physics.
    a. Heat transfer in a gas or liquid by the circulation of currents from one region to another.
    b. Fluid motion caused by an external force such as gravity.
3. Meteorology. The transfer of heat or other atmospheric properties by massive motion within the atmosphere, especially by such motion directed upward.
I had to check, wasn't sure of the exact definition myself. 

McGyver2 (author)PDRWLSN2011-01-05

Ah ok, thanks. I guess my definition of Convection was restricted to one thing. Thanks for the info :)

danielthomas72 (author)2010-12-06

Coool. You could power a Praxinoscope with that!!!
Brilliant feel to that sculpture, a work of art indeed!!

PDRWLSN (author)danielthomas722010-12-06

Thank you much. Might be a bit touchy getting it to turn at the proper speed and would need to use mylar for the mirrors to keep the weight down. Excellent idea.

snoopindaweb (author)2010-12-05

=/////=======> ~ Give that person a 10 ********** for "Do~able"...cOOl..YUP.!

PDRWLSN (author)snoopindaweb2010-12-05

Thanks! snoopindaweb

jeff-o (author)2010-11-29

Do you have the CAD files for this project?

PDRWLSN (author)jeff-o2010-11-29

Yes, didn't get published last night till 11:50pm so I had no time to include a video or the drawings. Will try to get them both in tonight after work.

jeff-o (author)PDRWLSN2010-11-29

Cool. Also, is that your own personal laser? ENVY++

PDRWLSN (author)jeff-o2010-11-29

yep, but had to choose either a new truck or the machine. Sadly the truck was destroyed in an accident 3 days after ordering the machine.

jeff-o (author)PDRWLSN2010-11-29

Oh I see what happened. You were driving distracted, thinking about your new laser cutter, right?

LOL, I joke. Hopefully no-one was hurt!

PDRWLSN (author)jeff-o2010-11-30

Yes. A taxi ran a stop sign, t-boned him at 45 mph no I mean 72 kph, no chance to avoid even if I wasn't distracted. We were both very lucky, only got banged-up a wee bit. It's been almost a year but I am still somewhat distracted.

Questor (author)PDRWLSN2010-12-05

could you use the laser on the taxi ???

PDRWLSN (author)Questor2010-12-05

Yes but it won't fit in the machine!

jeff-o (author)PDRWLSN2010-11-30


Questor (author)2010-12-05

opposing black diagonal lines on the rims of the rotors ??

PDRWLSN (author)Questor2010-12-05

My original drawings I used a checker board of hexagons engraved into the rim but thought it looked out of place and scrapped them.

darus67 (author)2010-11-29

Adding a chimney around the heat source would almost certainly improve the efficiency. I'm thinking nuclear reactor cooling tower shape. It would be more aesthetic than a can of sterno on a plate, too.

PDRWLSN (author)darus672010-11-29

Actually no, before I mounted the rotors to the sculpture body I held them over a propane torch. They turn very slow close to the heat source but about 6 feet away could almost lift themselves.Which gave me the idea for my next project, adding a stabilizer tube with fins and installing 4 model rocket engines to a single rotor. You heard it from me first!

randomray (author)PDRWLSN2010-12-05

I think they tryed that during WWII . Really . Didn't work as well as they thought it would . LOL

hintss (author)2010-12-01

I was about to say that it looked lasercut, then I say this pic. how much was that laser? how easy is it to bypass the door switches on that one?

PDRWLSN (author)hintss2010-12-03

The main door has 4 mag switches, the window has only 2. Using a laser to engrave fingernails and body parts isn't a good idea, ask anyone who has used one extensively if they have ever expected to run a raster job and by mistake ended up vectoring? The answer is we all have.

hintss (author)PDRWLSN2010-12-04

I'm 14, lol. anyway, I like the universal lasers more because of their interchangeable laser cartridges. and I was just curious. anyway, what was the cost of the 36EXT. I wish epilog and universal would put the prices up on the website like brightstar does.

mr.frob (author)2010-11-30

love the design, looks so good

PDRWLSN (author)mr.frob2010-11-30

Thanks, my better half said it looked "creepy"

Kryptonite (author)PDRWLSN2010-12-01

Does look a bit disconcerting, this awesome spinning thingo powerred by just a tiny flame!

PDRWLSN (author)Kryptonite2010-12-01

Thank you, disconcerting sounds way better than "creepy". Maybe I'll sleep in my truck tonight.

Foxtrot70 (author)2010-12-01

I don't understand how it looks "creepy" or "disconserting". This is really a great project! Hats off to you. The sculpture is using the laws of physics of hot air raising to move an object This happens everyday one only needs look at their local weather and see trees waving in the wind. I guess for some the world is still flat.

PDRWLSN (author)Foxtrot702010-12-01

Thanks for the comment. I had planned to cover it with tissue paper and doping it but ran out of time, kinda has that skeleton look in it's present state. Lotsa folks view clowns as "creepy".

Foxtrot70 (author)PDRWLSN2010-12-01

Actually it looks great as is. A variation which would give a "Futuristic" look would be to use plexiglass or maybe stainless steel and leave as shown in the current pic.

lw119 (author)2010-11-29

Looking forward to the video. Very cool.

About This Instructable




More by PDRWLSN:Moose/Bear Repellent aka FLAME THROWERDREMELCOPTER  w/ short movie clipPoor mans blast gate for laser exhaust or dust collector
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