Monday, 12 September 2011

Upside Down Tomato and Strawberry Growing

If you have ever wondered if growing upside down tomatoes or strawberries works the this investigation might be for you.

I bought two upside down planters from ebay for a total of $20 including shipping and headed off to the local garden center to find the rest of whats required. I ended up with a 25 litre bag of peat, a watering can and the plants. The tomato plant is from Father Tom from Floriana and the strawberry from Nellie Kelly

If your doing this for yourselves something to note here is the size of the plant, I didnt think to much about it until I started putting them into the planters. You need a plant with some roots on it so that the soil will hold the plant in place and stop it falling out the hole in the bottom of th planter.
You also need a plant thats no so developed that the root ball wont fit through the hole in the first place.

Mine only just fitted and in hindsight I would have got slightly less developed plants.The 25 litre size bag of peat that I got was enough to fill the two planters to the recommended two inches below the top and have a little left over for another day.

The planter kits themselves that I bought in consisted of a vinyl bag with a metal band around the top. The band has four metal cables attached to it which are in turn connected to a loop so you can hang it.
The inside of the planter bag has four straps from the top metal band to the stitching for the base which is help it cope with the weight and stress. There is a plastic rim which fits over the metal band at the top of the bag as well as a cap which clips into the inside of the ring. The cap has a whole in the middle making watering easy without removing the top. The planter also comes with a foam pad with a hole in the middle and large sturdy hook. The strawberry planters hook wasnt at big but Im guessing thats because it will carry less weight overall.

The weight of these planters is going to be considerable once you have filled them with peat, more when its nice and wet and more again when your huge crop of tomatoes are hanging from it. For this reason you need to make sure that whatever you screw the hook that comes with the planter into is very solid and secure. Pulling down part of your house just to grow some tomatoes isnt going to make the best financial sense!
I chose the eve endboard on the house and drilled a pilot hole a few mm smaller than the size of each hook before screwing them in. Which them in place and some heavy pulling on them Im satisfied they are not going anywhere no matter how many tomatoes I get.

Actually planting the plants in the planters is quite easy once you have a few things setup. Get a length of steel rod or fix another hook into a wooden board. Place that between two things that allow you to easily get at the top of the planters whilst having space underneath for the plant to hang. I used the corner between two balcony rails which was the ideal height although I suspect two workmate A frames or between two kitchen worktops would be good two. I placed the foam pad inside the base of the planter which apparently helps to stop the plant coming back out the hole.

Once setup I carefully removed the plant from its planter pot and even more carefully removed the soil from around the roots. I did this over the new planter allowing the soil to fall into it with the thought being that the plant would be 'used' to that soil. The now much smaller looking plant was then turned upside down to be held by the roots with my left hand whilst reaching inside the planter with my right hand. Moving the soil aside I pushed a thumb an two fingers through the hole allowing me to grasp the roots carefully and then feed the whole lot through the hole. Once all the roots when inside the planter I distributed them round and placed some of the soil on them. I then used the new peat to fill the rest of the bags to within about two inches from the top.

At this point I fitted the plastic cap on the top and then gave the peat a heavy drenching from my watering can. After a few minutes the excess water came trickling out of the whole where the plant is and continued dripping for about 15mins. After the water had more or less stopped trickling out I then lifted the whole planter off the rod I had used and onto the hook in the eves. If your doing this on a ladder be very careful, it weights alot now its full of wet soil!

Thats it for now, they are in place, one with tomatoes and one with strawberries. I will be updating on their progress when/if they have some and with any luck I will have lovely harvest later in the year.
If this works then the plan is (once we move to our new place) to build my own upside down planters rather than buying them and include such niceties as an auto watering system. Lets see how these do first :)

Sunday, 11 September 2011

The turbine works

One thing I did manage to get out my huge pile of stacked boxes is the tesla turbine variation I had been working on. It suffered some knocks in transit which resulted in the turbine rotor splitting into two sections. This wasnt a major problem but it did take some time to unseal the turbine housing and get it out.

I then had to go find new glue and sealant which is something I took for granted back in the Uk. As you live in a place for time you get to know where to find hardware you need and take it for granted that you can get it with ease. Over here in a new city and country all the things I need are here I just dont know where to find them!

After glueing the rotor back together and leaving under a pile of books while it dried I put it back in the housing and resealed it. At this point I thought I was ready to test and as I had access to a compressor I thought all systems where go. I was wrong, I wasnt ready in another quirk of UK to AU conversion, I should have realised that the compressor fittings are different over here than they are over in the UK. Some more investigation into the type and where I could get one it was a simple task to unscrew the jubalee clip and fit the new fitting.

Then I was ready :) I got the compressor fired up and waited until I had a full tank before connecting the turbine and slowly opening the valve. It works, the idea works! Its not well balanced, the rotor flaps back and forth quite a bit. Sometimes it needed a little encoragement to start to spin (I didnt want to just open the valve all the way, the pressure would pop the housing) Generally all these things where due to it having a lack of precision in the build but it actually spins. Im confident that if it was built with some engineering tolerences and a output power shaft introduced then rotational power could be extracted.

So due to my current circumstances this project is now shelved. I am having a little think about it from time to time about how best to build the better engineered one but for now the folloing video is about as far as its going to get.


If any of you make one then let me know I would love to see it and I would be happy to link to your site.

Im Back

So yet again nothing really happening with the blog! Sorry, its been to busy. Not log after getting to Aus I got a job which has ended up chewing lots of time and brain power. All my boxes have now arrived but I cannot get all my things out because there just isn't enough space here.

Whilst I would love to be getting on with creating solutions to things the facts are that like most people I need the money to save and buy a house. I love the idea of an off grid house which will in turn reduce outgoings over time but the reality is you need the money to buy the place first.

In the time until I can get a workshop up and running again I will be trying a few small projects in model form to see if the ideas work. If they do then i will look towards going full size with the best of them later on.

The original idea for this site was to create small power solutions that people could build at home. After lots of thinking whilst that will still be a component of the site Im going to expand it out to cover some other topics that Im interested in such as growing your own food.

After looking at where my life is heading it seems to make sense to start to do everything in my power to reduce outgoings thus allowing the income from the 'regular' job to go towards paying off the land and house purchase. Im assuming some of you are in the same position and so the ideas might help.

Like many I love the idea of off grid but without having the capital free to buy a place outright you would need to produce income whilst living off-grid. This would be in excess of whats possible given that your not doing a regular job. If you are doing a regular job then you usually have to be in commuting distance to the job which then locates you near a city so the land/property prices are higher which in turn means your less likely to be able to be able to buy outright any time soon. Its a great chicken and egg situation really.

Im aiming for the compromise of living a little out the city, working the regular job and taking the loan to buy the place. At the same time I will be looking to reduce costs my growing my own veggies, adding renewable power solutions and possibly even getting some chickens.
Its sort of half gridding it really. Being able to have some of the comforts of a modern life like the large television and fast internet connectivity whilst trying to reduce payouts to the regular every increasing energy and food corporations.

Tuesday, 12 April 2011

Apologies for the large amounts of nothing happening

  Sorry for the large large halt in anything happening here for the last eight months. It really does not feel like that long since my last post but the dates don't lie! I have spent the time organising, packing, finishing things and relocating to Australia. I have been over here about four weeks now and starting to settle in. More or less everything I own is now in transit on a ship somewhere, Im just hoping it makes it here in one piece!

  On the up side when I was tidying things up I rediscovered lots of things :) Amongst this I found the original circuit diagram for running a 12 volt battery up to the kind of voltage and pulses required for creating a very satisfying spark arc when run into a standard car distributor coil.

  Now Im almost on top of all the official paperwork that needed to be done to be here I will collate what I have tried and built for the hydrogen splitting experiments and get that up online. Once my boxes arrive and I have my equipment up and running I will at long last be able to test the modified Tesla turbine.

  One area Im very much looking forward to looking into now Im here is anything to do with the sun. There is quite a bit of it (which makes a nice change!) and it seems so underused as a power source. PV cells are great if you can afford them but the power you get back for the cost is huge. They are also not exactly something you can create yourself in your garage or shed. Im having a think about it, I will let you know what I come up with.

Thats all for now (but still loads more than you have had for ages :)

Saturday, 14 August 2010

Gasifier information - at last!

Woodgas rocket stove

Sorry for all you readers who have been searching to find this and haven't, I know I have been rubbish at putting updates on but life gets in the way. This update describes the building of a wood burning stove sometimes described as a rocket stove due to the forced air for combustion. It uses the principles of initially burning the wood in a reduced oxygen environment which causes the release of woodgas. This gas is then burnt elsewhere (in this case slightly higher in the stove) in the presence of plentiful oxygen. This allows a much cleaner more efficient burning process with next to no smoke and also breaks down virtually all the wood to charcoal. If you follow this you should be able to build one of these yourself but as usual I will not be responsible for anything that happens to you as you build it or operate it or whatever you burndown!
When I started investigating woodgas stoves and decided that wanted to make one I didn't want it to be two complicated. There are some fantastic designs and builds in many places on the web but I would suggest you check out for loads of background to the process and some very professional builds. I thought about the process for a while and the resources that I have to hand. That basically equates to things I could buy from local diy and household superstores all built with simple tools. So if your looking to build one of these what you will need it the following :-

Parts list

One all stainless steel flask (which I think is a one litre one) purchased from Poundstrecher for £5 but similar are in Tescos.
One standard can of Wests tuna (I got from Tescos)
One 40mm computer case fan or similar(I had one lying around but Maplin have them
Power for the above fan. As mines a case fan its 12v so I power it off a jump starter battery.
Four self tapping screws about 25mm but any length about that should do.
Four nut and bolts to hold the fan in position. I think these where 4mm but whichever fan you get the bolts need to fit the mounting holes.
One long point nail or preferably a centerpunch


A drill (cordless is easier but corded would work)
Drillbits 3.5mm, 6mm, 10mm
Screwdriver to fit the screws your bought
A set of pliers and spanner to fit the nuts and bolts you bought. Two spanners or two sets of pliers will work.
Flat file
Permanent pen.

Stage One - Prep the flask
Remove the cup on the top of the flask and put it to one side.
Unscrew and remove the plastic pouring cap and throw into your spare parts bin :)
Turn the flask upside down and inspect the base section. The flasks are made of an inner and outer skin with a vacuum between them. To create the vacuum the air is expelled through a hole in the base which is then sealed and then covered with an endcap. That endcap needs to come off for what we need to do with the flask and I found two methods of doing it.
The first involved drilling a small hole in the base and then blasting an air duster can into the hole. The increase in pressure pops the base off with a satisfying bang. Beware though if using this method as the base will fly across the room will considerable force and do damage to what/whoever it hits.
The second and safer method involves drilling a hole 10mm up the side from the base. Mark where you are going to drill the whole, 10mm up from the base which should be about 5mm down the flask from the join of the base to flask. Use the hammer and centerpuch (or nail) and make a nice dent where you have marked. This will help stop the drill from sliding around. Place the flask in a vice if you have one, if not place on the floor and hold at one end whilst using the drill with the other hand. Keep your hands and anything else fleshy well clear - if the drill slips and you drill yourself it will hurt! Carefully drill through with the 3.5mm, you only want to go through the outside base of the flask. Next expand the hole using the 6mm. Have a look inside the hole, you should see the inside edge of the base of the flask where the inner and outer halfs are joined. Use the screwdriver or the centerpunch (or nail) poked through the hole and pressed towards to bottom to lever off the base.
With the base off you should be able to see the copper valve roughly in the center of the flasks base where the vacuum was done.

Stage Two - Drill lots of holes
Look inside the flask from the top. At the very top the inside and outside of the flask meet, about 3.5cm down the inside of the neck there is a ridge all the way round. Use the marker pen and mark a dot on the top edge of that ridge. This will be location of the first of the set of secondary air injection points. Mark the second mark directly opposite the first then the third and fourth half way between each of them. Take two of the marks and mark another between them, keep dividing and marking until you have sixteen marks at equal spacing. If you fail you can always wipe the marks off and start again.
That done, flip the flask over to so you can place marks of the base. The base has ridges on which makes things a little easier for getting spacings but you don't have to be two precise. Mark four points around the center vacuum valve at equal spacing. Your going to drill 10mm holes here so make sure you have enough space from where the edge of the 10mm hole will be to the vacuum  - if in dought check with the drillbit that your going to have enough clearance. Next mark another eight at equal spacing slightly further away from the center making sure (using the 10mm drill) the holes are not going to overlap. Check the pictures further down to see the spacing I used.
Use the centerpunch again and dent each of the marks you have. Now drill the first hole with the 3.5mm drill. Careful here, it is a vacuum flask and that first whole will destroy that if your denting process hasn't already holed the flask. Drill through the outer flask then push the drill in about another 8mm and drill straight through the inside base of the flask. Repeat the process for the other eleven dents you have made.
Flip the flask and drill the sixteen dents in the inside of the neck you marked out earlier. Note this section you are only drilling through one wall of metal with your 3.5mm drill.
Flip the flask back to the base again and change up to the 6.5mm drill. Expand the twelve holes all the way through both skins. Now switch up to the 10mm drill bit and carefully expand ONLY the twelve OUTER holes.

Stage Three - Have something to eat
Next open the can of tuna and have a break eating the contents. When opening the can use the can opener all the way round completely removing the lid. Remove the label from the tin then mark a point about 15mm down the side from the top. Mark another again at 15mm down on the opposite side then again between the two marks and again opposite that. Keep marking until you have lots of marks all round about the side of the can 15mm from the top but again be careful not to overlap the 10mm zone. Turn the can over - the sealed end is now the new top. Place your fan in the middle on the top of the can and carefully hold it in place whilst using the centerpunch (or nail) through each of the fans mounting points to dent the can top. I know you need more hands than you have for this task so getting some help may be in order here. Whilst the fan is still in position poke the marker pen between the fan blades and drag it around the outer of the inside of the fan housing. When done remove the fan and you should be left with four dents with a large circle in the center marked in pen. You want to remove as much of this circle as possible so use the centerpunch to dent within this circle remembering the 10mm overlap rule but try to make as many areas to remove as possible. If you manage to remove the whole circle section then great as it will improve airflow.
Use the 3.5mm drill to drill out the four fan mount wholes and all the wholes round the edge of the can you marked earlier (now 15mm up from the bottom edge) Be very careful when doing this as the cans edges and the edges on the holes your drilling are very sharp and will produce very effective deep cuts! Carry on drilling by drilling out all the dent you made in the circle on the top. Switch over to the 10mm and expand out all the edge hole round the can and the circle. DO NOT drill out the fan mounting point holes. As I said earlier remove as much metal as you can from the inside of the area you marked on the top of the can in the circle. Take your file and file down all the rough edges around the holes you have drilled.

Stage Four - Assembly
Take you fan and now place it inside the can with the flow allow on the side of the fan pointing up and lining up the holes you drilled in the top with the mounting holes in the fan. Push through you four bolts in turn and add the nuts on below the fan. Tighten with the spanners or pliers. Stand the flask upside down and place the tuna can with the open section upwards on the top (which is the base!) Use the centerpunch and dent four marks out between the inside edge of the tuna tin and the outside edge of the fan (along the flat edges) Carefully hold the flask and tin together and drill through the tin and bottom of the flask with the 3.5mm drill. Again a vice or helping hand would be good here. After drilling screw the four self tapping screws through the tin into the flask to join the two together. Note where the wires are coming out the side of the fan and estimate the height and position on the outside of the tuna can. Drill a late 3.5mm hole through the can at that point (you know how to mark and dent by now!) Thread the cables through you new hole from the inside to the outside.

That completes your build, well done!

You can use twigs and other small burnable material to fire this up but what you really need it a regular sized and shaped fuel of a regular low moisture content. I wont explain the ins and outs of moisture and bridging here but please refer to the info on to find out more. After trying various fuel sources I eventually settled on organic cat litter. Its the right size and shape and has a regulated moisture content. Its also not to expensive and readily available. Its basic compressed wood pellets which is ideal :)

You need something to start the whole process going and I recommend Tescos bbq fire lighters as they have phosphorus embedded on the end which makes for easy lighting. Other people fire up their versions of toplit gasifiers using lighting gel. Whatever you use be careful.

Firing it up - The fun bit :)
Ok heres the fun (but potentially dangerous bit). Place the rocket stove on a flat fireproof surface and cable up the battery to the fan and test the fan fires up. At this point you should be able to feel a nice little draft getting pushed out the top of the stove. If your getting no draft and the fan isnt spinning odd are the blades are jammed on some part on the tincan. Disconnect the fan, take the tin off the flask and check it all out, filing, bending the can until the fan spins. Reassemble and recheck.
Once the fans spinning and you have confirmed draft disconnect the fan. Fill the stove with cat litter pellets until its about 4cm under the lip which you drilled holes in in the neck. Light up a lighter block and hold onto it long enough for it to burn well but not long enough to burn you. Once its going drop it into the neck of the stove and let it burn for a few seconds more on its own. Now connect the fan up and observe the increase in flames due to the forced air blast. After a few minutes the lighter block will burn down and set light to the top layer of woodchips (cat litter) As its burning in a reduced oxygen area the gas float off the fuel and gets pushed up to the neck of stove where it burns in the second forced air blast. You will see in the neck the flame will appear to float as the fuel burns down inside the stove. Eventually (mine runs for about an hour) the fuel burns to near nothing and the flame turns a blueish purple and is less aggressive for a time before it goes out. Once the flames out you can disconnect the fan power feed and leave the stove to cool. DO NOT attempt to pick the stove up or touch it it gets very very hot! Leave it for half a hour or so then carefully check to find out if its safe to touch. Tip the dead charcoal out (excellent for your plants) put the flask lid on and then pack up - job done.

General Musings
With the addition of a stabiliser to keep the stove upright and incorporating a pot stand this would be a very effective camping stove. A feed for the power could be easily taken off the cars lighter socket. Fuel can be left in the stove with the lid on and as long as the environment its stored in isn't damp. If anyone makes one of these with such a stabiliser and pot stand I would be most interested in seeing it.

Tuesday, 10 August 2010

Not much progress really but here are a couple of photos of the new valve installed on the top of the turbine.

Tuesday, 3 August 2010

New valve

Bought a new valve tonight which should do the job. I finally settled on a 15mm gas valve from B+Q
It was in the gas fittings section and described as 'gas lever valve 15mm'. It has 15mm compression fittings on both sides so it should easily fit the rest it the setup and its a nice chromed metal design so it should take the presure.
Next step is to plumb it into the compressor fitting on one side and the turbine on the other. Hopefully this should happen either in the evenings this week or next. Im out this weekend and work is really getting in the way the rest of the time!

With any luck testing shouldnt be to far away. I was thinking about it all earlier and if this turbine design doesnt work I might build one as close to the Tesla design that I can and use the same housing. This will mean a slight redesign of the input so that its a nozzle but it will be much quicker than having to rebuild the entire turbine housing. It wouldnt have a power take off but it would be nice to see something spinning :) Then again there are plenty of other projects I want to investigate and so little time :) I am aware I still havent documented the Stan Meyers hydrogen stuff and woodgas turbo stove research I have done. Sorry to all those who visited the site wanting to read these sections. I will get round to it honest! Probably do the woodgas turbo stove first as its the simpler to explain and document.  The hydrogen section is a bit trickier requiring cylinder construction, low voltage electrolysis/electrode design and high voltage work all with circuit diagrams and explanations.

Wednesday, 28 July 2010


I have been doing some testing on the standard 15mm speed fit tap value for potential use as an input pressure restricting method.
  I didn't hold out much hope for them but as they are cheap I thought I would try one. I used epoxy to glue a standard airline fitting into a speed fit connector. After this a small bit of speed fit pipe was inserted into the other end and then that then inserted into the test valve.
  The airline was connected up and the valve closed. The compressor was turned on and allowed to build pressure.  During pressure build I opened and closed the valve and although it acted fine it wasn't very easy to get a small amount of pressure flowing. It was very easy to get all or nothing.
  I set the value to the off position once again and let the pressure continue to build. Standing well back at this point I nervously waited for the compressor to cut out meaning that it was at its max. Unfortunately it was at this point my decision to stand well back was justified as the valve couldn't take the pressure before and blew up with quite an impressive bang followed by a lot of hissing!
  I really need a valve that will handle all the pressure so I can be certain that I can shut off the turbine at any point and be safe. I have spotted some brass valves with nice long handles on which should make for easier fine adjustment. I will pick one out, get it tested and report back. 

Monday, 19 July 2010

After having a big think about things at the weekend I postponed making the connector between the compressor and the turbine. I had a quick thought when looking into what compressor I have access to. Its huge and by nature contains  massive pressure, once connected this is unregulated. Putting that much pressure through the plastic glued turbine all in one go will very probably cause it to explode and cover me in little bits of sharp plastic! I therefore need a way of regulating the pressure so some form of valve is in order. Ive looked at a couple of places so far trying to find a suitable off the shelf unit but so far nothing suitable. Ill update once I have found something :)

Thursday, 15 July 2010

Its finally assembled !

I finally managed to get the time to assemble the turbine into the housing after first fitting the input tube in. After that I sealed it all using the silicone and let it set. The following pictures show the completed unit from various angles, note the marks on the turbine where I had to remove the edge disk and take off the spacers I put on the wrong way (Still annoyed with myself over that!)

Next stage is to get a loan of a compressor and see what connector it has on its output. I will then need to make a converter between that and the 15mm speedfit input of the turbine.
Hopefully I will be able to get on with that task for a portion of this weekend, fingers crossed :) Darren

Tuesday, 13 July 2010


Ooops mistake! whilst checking things over before assembling the whole thing I noticed I had fitted the spacers the wrong way round between two of the disks. To sort this out I had to carefully use a knife to cut through the glue and separate the disks away. The spacers got trashed in the process and Im out of spares. Its annoying but the unit should still work with one less disk/spacer. I have now glued a new endplate on and Im waiting for it to set before starting the assembly.

One the up side I have fitted the input pipe as detailed in the previous post and sealed it with some wicks all weather silicone sealant.

Monday, 12 July 2010

Turbine input fitting

I have now drilled out the pilot hole to 20mm using a step drill from halfords :-   cat code 192393
This allows insertion of the 15mm compression pipe connector by removing the olive from one side, putting the thread through the hole in the ABS then putting the nut back on. After tightening up its nice and solid in place :-

From the top
From the underside  (looking up from inside the turbine housing
Next stages are to use the olive still left in the top of the fitting to mount a section of 15mm speedfit. This will allow easy fitting of tubing using off the shelf plumbing parts to plumb it into the compressor or air source. After fitting this tube I will seal round the fitting inside and out with silicone and also fit the turbine into its housing and seal that in. Once the sealant is set the unit will be in a state to test and find out if all of this has been a bit of a road to knowwhere :)

Thursday, 1 July 2010

We here are the promised photos, not that good quality so I will try to replace them at some point will better quality ones.

This pic shows the initial template of the spacer I made for keeping the disks apart whilst allowing airflow. Also shown is the 15mm pipe and pipe insert used as the rotor mount.

This is the completed rotor with a line marked on it in permanent pen to better show spinning.

Heres the completed turbine housing without the front cover installed. Notice the 15mm speedfit pipe and insert protruding through the middle and the space mounts in the four corners.
This is a top shot of the housing with the rotor mounted with the front panel on. I have drilled a hole through the top which I will be expanding out to fit the air intake pipe.
This top shot better shows the pilot hole.
The above two show the turbine in its housing with from different angles.
Thats all for tonight :)

Tuesday, 29 June 2010

Life and its little delays

Sorry about the wait for the pictures of the test turbine, things have taken a back seat for the last couple of weeks whilst we have been preparing for Glastonbury. What an amazing mind blowing festival that is! I recommend it to anyone whos into any kind of music or just likes a good party :) So tired now, I would advise anyone going to pace themselves a little better than we did ;)

Doing some web wandering and came across the following site :-
Hes creating a mulch powered heating and methane unit using simple easily available parts and feedstock. Its all very cool and I would love to give it a go once I have the space so Im watching it closely.

One thing I did manage to think about was the input side of the turbine. I picked up a straight through 15mm brass compression pipe joint from B+Q ( I should be able to mount that through the side (top) of the turbine using one half of the connector without the olive. The other half can be used to fit the input pipe on using that sides olive with the whole thing being sealed with silicone.

Ok tonight's work is getting the camera operational and getting the pics of the turbine, next post should be them, promise :)

Sunday, 13 June 2010

Ok, After thinking about where to start for a bit it kind of makes sense to get up what i'm doing at the moment which is the tesla turbine and my theoretical improvements. First lets go through Teslas turbine :-

Tesla found that a gas or fluid being forced between two closely spaced flat entities exhibited an adhesive drag on those entities. He than moved forward with this to design and build his first turbine. This consisted of a set of closely spaced flat disks held together with washer spacers between plates. The center of each disk had a wide hole and a cross shaped support joining the disk to a central shaft. Pressurized gas was forced in at the space between the disks at an angle where it spiraled towards the center of the disk and allowed out through the cross shaped support. I have attached a pic of Teslas design pic.

A photo of Tesla's own revolutionary turbine.Image via Wikipedia

···As a home researcher unfortunately I dont have access to some nice computational fluid dynamics packages that would be very useful here to calculate the gas flow through the turbine and hopefully see methods of improvements. The only methods available to me (and lots of other people I think) is stitting and thinking and then building it and seeing if it works. Lots of talented people have built up Tesla turbines and there are some very nice utube vids of them spooling up. It seemed a duplicated step to build one myself so after looking at many builds I sat and thought lots about it all.

···The key theory from Teslas boundary layer turbine seems to be that the gas is injected at the edge of the disks preferably using a nozzle assembly to inject it between them. Gas should then spiral in and exit the disk in the center. As the gas travels on its spiral towards the exit it exert its adhesive force onto the disks and the pull on them starts the disks spinning. My thoughts about this lead to the idea that the more uninterrupted the flow of gas from input to exit the better the transfer of power to the disks. Its known that a well designed nozzle inserting the gas between the disks works better than just inserting it across the whole outside of the disk array. This reduces external turbulence with gas flow injected where its needed.

···My potential improvement focuses on the central area of the disk where the gas exits between the disks and where in Teslas design the star shaped support is. In an ideal implementation (I think) the disks would be placed closely together with the gas injected at the edge and exit in the middle. The gas would have an uninterrupted flow through out its entire path.
···In teslas build the star shaped spacers at the centers of the disks only allow the gas to exit when it can get to one of the four sections where the star doesn't protrude from the center to the edge. In a test where the disk and therefore star was held stationary whilst the gas was injected the gas flow would stabilize to flow towards the center, bump into the protruding star supports, flow round them then exit. This would create flow eddies and areas where the because the spiral flow was not wholly spiral the power to the disks would be reduced.

···Now thinking about it as a spinning disk. If the gas injection flow is constant that central spinning star will create a slow moving obstacle at initial startup causing huge eddy flows. As the turbine spins up these eddies will change which will change the spiral gas flow and hamper power transfer. In (my) theory each size of turbine of this type would have an ideal gas flow rate where the input to the turbine matched the spinning star to the point where the gas flow was least impeded.

···So the theory is that disks with no supports in the center and spacers at the sides would work well for gas flow. Unfortunately holding the disks in this position and getting power output from them would be impossible (well for me anyway). I therefore had to think of a way of keeping the disks apart whilst holding them impeding the gas flow.

···What I came up with is the stack of disk would be held apart with spacers at their edges. The spacers will be shaped to allow gas in then 'aim' it towards the direction of flow to start the spiral. The centers of the disk would have no support between disks with the exit hole free to accept flow from all angles. The end two disks will have central pivot acting also as an exhaust for the gas. The disks will be encased in a chamber which is then pressurized. The gas gets pressured into the input holes between the disks spacers, from there directed sideways encouraging it to start its spiral flow to the center. At the end of the spiral it enters the center of the disk and heads sideways to the exhaust at the end. In my theory this will work :) I need to build one to test the idea it doesn't initially have to have a spinning output shaft, just spin the rotor which should make a build easier.

···As I dont have a nice machine shop of my own and I cannot justify spending out on getting a unit made just to test the theory I needed to make a test unit up using parts I could work with and bits I could get hold of. I settled on 8 cds for the disks as they are nice and flat, readily available and can be glued. My local plastics shop was nice enough to donate some abs plastic offcuts to the project. After looking into a few things to act as the central rotors/exhaust simple speedfit pipe and 2 pipe inserts offered the most readily available and cheapest solution available. I also bought from the plumber merchants some plastic glue of the type used to glue abs pipes together and some silicon sealant.
···Below are the dimensions for the turbine housing. The plastic was cut using a jigsaw from B+Q setup on a workbench using gclamps.

···To get the whole through the center of each end panel I marked out the center on one, clamped the two together then drilled through them both. I started with a small drill bit and expanded up to the 15mm that is the cd center size and the speedfit pipe size. After that I used the ABS pipe glue to glue together the housing sections, the two shorter end sections first followed by the longer ones. Using a bit of the speedfit pipe through the center of both end panels helped to hold the whole thing in position while the glue started to go off. In glueing it all together I only glued in one end panel allowing turbine insertion. After the glue had set overnight I glued in the corner braces which also act as spacers for the end panels. Another overnight glue set period happened.
···Next I chopped two twoish inch lengths of the speedfit pipe up and inserted a pipe insert into each. These where then inserted into the end panels with the inserts facing towards each other (to the center of the turbine housing) This was the housing nearly done, just the end panel to put into place once the turbines in and then silicone it in.

···Turbine parts where next and these where the trickyest to manufacture. Below is a diagram of the turbine spacer. I haven't taken the dimentions off it (tricky with all the curves) but basically its four of these per two disks (to act as spacers). These where cut out of more CDs using the jigsaw and lots of swearing! CDRW seem to work the best for cutting as the plastic is different than others as they dont seem to crack and shatter as much. After an age of cutting I ended up with the required 28 of these. Seven of the eight disks where now marked with a pen to provide starter marks where each of the four spacers would be glued from. The easiest way I found to do this was to mark a disk anywhere on its edge. Next use a ruler and measure 8.5cm across the disk and mark where it intersects the edge. Do this twice more and you should have four marks all 8.5cm away from each other. The spacers where then glued onto the disks and carefully compressed under a weight overnight. Next I got a cd pack case that usually holds a 100 disks and has a shaft up the center. One cd with the spacers glued to it was placed over the shaft with the spacers facing up. Glue was applied to the tops of the spacers and the next cd placed on top (again with the spacers facing up). Each cd was offset from the one below it by 90 degrees thus offsetting the inlets. After all the disks with spacers where placed the final disk was placed on the top followed by a load of weight and left overnight.

···The turbine complete I now placed it into the turbine housing placing the center of the end cd onto the speedfit pipe insert mounted in the rear panel. The front panel was fitted again lining up the center of the cd onto the pipe insert. The panel sits onto the housing corner supports which in turn sets the distance the panels are set apart. The speedfit pipes can be carefully pulled or pushed back and forth to set the inserts into the centers of the cds and increase or decrease the friction.

···An air intake is required so I thats what I need to work on next. I did think about drilling in another 15mm hole in the top of the turbine housing to accept a bit of speedfit but because of the plastic type of the pipe it wont glue with the glue Im using for the ABS. Im having a think about it hopefully something will spring to mind.

···The turbine spins freely given a twist of the housing which is promising. Soon I will need to borrow a air source such as a compressor, build up a valve and pipework to connect the two then try it. Im fully expecting this if it starts to spin to whizz round to the point where it jumps off the pipe inserts and the turbine impacts into the abs turbine housing. I fully intend to be standing far away at any point during testing this. If it does do this though I dont mind to much as it will have proved the theory. I will then look towards improving it and building another out of alloy with proper bearings and a power takeoff of some sort. Fingers crossed and I will report back.

I will get some photos of the turbine and housing sorted and get them posted over the next couple of days.