Wind Driven Kite Bubble Generator
Mark 2

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Prelude

This is my second attempt at a wind driven bubble generator. Simular to but also different to the first generator I built. (See the Mark 1 generator)

Results -- Almost but Not Quite

CAUTION: I built this generated (see photo at bottom of page) but it does not quite work correctly. It should however be possible to make it work.

The main problem with this generator is that the container presents a flat face to and aft of the wind. This creates turbulence in the wind, so that while bubbles are created, the tubulance pulls them toward the flat back face of the container where they burst, in a mess. Only a couple of bubbles, every now and then escape the eddies.


Requirements

ASIDE: All the above stuff totals under $10 Australian including the bubble mix. The LEGO however may not be so easy, particularly the worm gear.

Construction

Step 1 -- Rotor

[photo] [photo]

2 lengths of coat hanger wire was pushed through a bit of plastic tubing, right angles to each other. A smaller diameter is inserted into one end. A LEGO spindle will be pushed into the plastic tube so get this smaller tube correct. The ping pong balls were halved and a small hole bored through near the edge on opposite sides. A heated precision screw driver (or wire thinner than the coathanger wire), does a clean job of this.

The ping-pong balls are then pushed onto the end of the coat hanger wire of the rotor. NOTE: the ping-pong balls must face in the opposite direction on the other side. Super glue the plastic tubes together and the ping pong balls. DO NOT glue the lego spindle spindle into the smaller tube. the plastic should grip it tightly enough on its own.

Step 2 -- Container

[photo] [photo]

I Cut off one side of the container (both lid and side of container. then superglued the lid permentally onto the container (see photo). I found that if you fill the gap between the container and the lid with superglue (or crazy glue) ( Do this in a very well ventilated area) and then with a small precision screw driver or wire push bluetack (used for tacking posters to the wall) into the superglue, a very solid bond will be created.

Wait until very dry (next day).

A hole made in both the base and lid of the container (dead center) just large enough for on of the lego spindles. The loops will be attached some how to this.

Step 3 -- Mount for gears and rotors

Look carefully at the photos above. The spindle through the container has a small lego gear on it. This gear is to be driven by a lego `worm' gear. By doing this a 1 to 8 reduction in speed is achieved and a 90 degree turn. IE: the loops rotate in a plane perpendicular to the wind!

To position the worm gear, I used blue tack and superglue to glue small lego blocks to hold the rotor lego spindles. after the glue is dried a second layer of bluetack and superglue is moulded around them to ensure they say well glued to the container.

These blocks required very careful positioning. If I had to do this again I'd probably only use two larger `wheel' blocks rather than four small yellow ones shown. The friction I found from my setup was too great, even though the spindle turned freely it still rubbed a bit :-(

Step 4 -- The Bubble Loops

[photo]

The Loops were twisted out of pipe cleaners. Make the loops as large as possible that fit in the container and think on how you will attach them to the spindle running through the center.

I used a LEGO helicopter rotor piece, threading the pipe cleaners though the LEGO's ready made holes.

When assembling the main container, place the rotor close to the back face furthest downwind. This stops the bubbles hitting the container edge. I placed the gearing on the upwind side.

Step 5 -- Line Attachment

[photo] [photo]
I had a old wood ruler handy which I used to wire/tape a hinge and kite line knobs. This handle is needed to keep the generator facing into the wind.

The Kite line is attached to the knobs by just looping the line once around each knob.

Completed Generator

[photo]


Dated: 12 June 1996
Updated: 12 June 1996
Author: Anthony Thyssen, <anthony@cit.gu.edu.au>
WWW URL: http://www.cit.gu.edu.au/~anthony/kites/bubbles/mark2/