DownDraught Files

Here in the Downdraught Files I shall indever to document the things I happen to feel like making, so far there are only two of them, but depending on the free time I have the list might grow, you never know! :)




Spudgun Back to the top

Well just the other day I thought you could only fry, bake, boil, mash and soute potatoes, that was until I found www.Spudgun.com. Now these things are dangerous and I recommend that you read all the warning at the above site before attempting to build one. The design below came from spugun.com and took only a couple of hours to build and cost about 25.50 GBP. Heres what I made:

The red bit and is about 10 inches of 4inch diameter waste pipe and forms the chamber. On the ends are external fitting screw on caps (the most expensive part) one provides access to the chamber and the other has a union fitted to accept 1.5inch waste pipe(36 inches long), I had to do this as I could find any glueable 1.5 to 4 inch adapters.
I then filed down the end of the 1.5 waste pipe to make a knife edge so when the spud is ramed in it cuts a core out. Next I stuck the lot together using the special glue required for this type of pipe.

Next I drilled 2 holes to allow screws to be driven in, I differed from the spudgun.com specs as I didnt have any 2.25inch screws. As these screws where shorter I couldnt bend them so I had to wrap a piece of wire around the end of one to reduce the gap.

Anyway no the fun part, the device is fuelled by hairspray, it doesnt seem to make much difference what brand is used but it doesnt half stink once burnt!!!
The screws act as electrodes for a peitzo(?) electric spark generator, they can be found on gas cookers and BBQs. The gap is ~0.25 inch and it gives a nice big spark, if it is too wide then there will be no spark. Its also very important to get the correct amount of hairspray in the chamber, I find that about 2 seconds (ie [start spraying] '1 one thousand 2 twoonethousands' stop spraying) too muh hairspray and it wont fire, I find that if you take the cap off and blow into the end and replace it it will usually fire after that.
The range is impressive I havent had chance to calibrate is but I fired it straight up and I think it was in the air for ~10 seconds, wind shear brought it down on the roof of the house(50ft away from launch) where it disintegrated on impact and fortunatly didnt brake any of the roof tiles. Im now not to use it near the house!!!


Well I made up a stand and have been shooting it up the field. I was suffering from wind shear and from what I paced out afterwoods they were going in excess of 100yards. Which is not bad for the core of a potato propelled by burning hairspray!


Windmill Back to the top

Years and years ago I was bought a book called "Windmills and Wind Motors" by F. E. Powell ISBN 0-917914-27-9. This book describes the fabrication and construction of various windmills with sail diameters from 1ft to 12ft. I tryed to make one with 4 sales when I first got the book that had 4 sails but at the time was rather unsuccesful. Then just the other day I found the book on my books shelf and decided to try again.
Now I wanted sails of about 3ft in diameter but I didnt like the design of the books windmills that were of about this size so I merged several designs to come up with mine. Now mine stands 4ft 10 high and has a span of 3ft3 from sail tip-to-tip. A couple of pictures can be seen below:






Now as you can see it has 6 sails and is capable of steering itself into the wind. The rotation of the blades is converted into a vertical rotating motion by a pair of equal sized bevel gears.
the most complicated bit I dont have a photo of as its hidden by the piece of ali thats keeping the weather out, to allow the whole lot to swivel. to solve this Ive made a little sketch:


(scuse the mess but its what you get for shrinking & compressing it before you realised youd made a mistake)

Now 1 is the bottom bevel gear, 2 is the housing for the bearings that carry the sails and for the top roller bearing, 3 is top roller bearing attached to the 2 by a metal ring, 4 is the bottom roller bearing attached by the same means, 5 is the base plate that hold s the whole lot to the top of the stand, last but not least 6 is the main shaft that carries the weight of the sails and the hub but also transfers the rotory motion from the sails. It can do this because of the two bearings which allow the shaft to rotate indepedantly of the hub and base plate.

The sails are made from 3ply and the arms and hub are mohogoney(I cant spell!) which we happen to have more of than any other hard wood. The sails are inclined at 30 degrees, I gave the windward side of the sails a couple of coats of sanding sealer and then rubbed them down, after giving the whole thing a couple of coats of varnish Ive got a glassy finish on the sails which will hopefully reduce the drag. As for the rest of the construction Ive used lots of brass screws and everything wood has been varnished many times, most other things have been painted.

News as off 21st of August 2002:
To keep up with standard progress its not driving anything. I have, with help from my dad, remade the base so the hub runs on bronze bushes with the shaft carried by bearings through the centre.
Unfortunately due to some strong winds all of the sails are broken and it is in rather a sorry state, but soon, when I have time (lol). Im gonna remake the sails from ali and bolt the thing to the ground. Then whens it working properly I might try to get it driving something!

Created By: Anthony Godden
Created On: 15-September-2001 Last Updated: 21-August-2002