12/30/02

Dotsony

dotsony@earthlink.net

Subject: (continued from 12/15/02)

I'm not a machinist, and I don't have the required tools to build a metal turbine. I also don't have the funds to get pieces made for me. I had planned to do my own more extensive follow-up to __'s experiments with paper turbines over winter break. Actually, I plan to build some small mock-ups out of acrylic, or polycarbonate (the former being cheaper, the latter being easier to work with). I have access to an air compressor, so providing a working fluid at a consistent pressure should not be a problem.

The main question I want to answer for myself is if a Tesla turbine, with all the spacers and washers, is actually more efficient than a bladed radial turbine. I also want to look at nozzle shape, length and diameter. Then I'll scale up the best design, and try to achieve the same efficiency. Basically I want to figure out how to build the turbine first. Then, assuming I get that far, I'll work on combustion chambers separately, and, when I've found several designs that might work, I will test each one on a metal turbine identical to the scaled-up plastic version..

I don't know if I'll ever build a tesla-powered go-kart, but that would be cool. Some questions I have for you:

1. Pulse combustion: Is it really viable? Which reminds me, I can't make any sense of those pulse combustion chamber drawings on your website.

2. I'm going to measure torque by lifting various weights, but I found an electric clutch in a surplus shop that might allow me to engage the load while the turbine is spinning. That should work fine for the mockups, but I don't know what I'm going to do when I get to the real thing.

3. Do you think it would be possible to simulate pulse combustion by repeatedly opening and closing a solenoid valve?

Some more suggestions I have: I noticed you use frequency counters to measure engine RPM. It is trivial to wire the schmitt trigger to a PC game port (joystick port) and write software that will give you a reading in RPMS. Just about any old (cheap) piece of crap will work for a computer (potentially easier to find than a frequency counter), so if you want I could give diagrams and software for your readers. But I must ask you, What kind of Hall effect sensor did you use? I used a magnetic reed sensor sold as a security system component for a similar project involving a 3hp lawnmower engine. I got erratic readings above 950 RPMs. It could have been interference from the magneto, but I think it was more likely that I was exceeding the speed of the switch. Which is why I need to know what kind of sensor that was!

3) Pulsing air flow on and off through a solenoid valve will simulate pulse combustion, but the goal in pulse combustion is to achieve a high rate of fire -- to approach a continuous outflow of gas.

The hall effect switch we used was purchased at Radio Shack. Other sources are Digi-Key and Jameco. Also try Allegro Sensors for samples and app sheets. Once you have a working circuit and software development we would welcome your contribution to the cause. -- Ken

12/24/02

Richard Davies

richard@tollyboy.com

Subject: Steam consumption

I am specialized in high temperature chemistry (plasmas) my company is Glycanmetal we are located in Spain we are private company. I consider TESLA as a genius!

we want to associated Tesla turbines and/or compressors to our plasma machines, working 2000-5000 K , we could make ventures, someone of your group could realize for us one prototype at the beginning the dimension could be 21 cm for disks - we would furnish the disks if necessary - the classic turbines do not resist to high temp

- in advance thanks and Happy Holidays

12/23/02

Brandon Lewis

atanyrate@hotmail.com

1) "Do you think that a Tesla turbine would make a good beginner’s project?"

It’s easy enough to build if you have enough shop hours to put in and limit the number of disks to about five.

2) "What do the star washers do? Wouldn’t smaller spacers at the center & around the through bolts be better suited...?"

Tesla’s advanced patents show a star washer. They tend to create additional lift as the gas exits the disk pack.

3) "... a Tesla turbine’s configuration does not permit a very efficient use of space. The intake & exhaust are at right angles to each other, making staging or coupling a compressor to the output shaft a plumbers nightmare... Is there a solution to this problem... ?"

As long as you use rounded elbows and no sharp turns the losses are minimal, so you can orient the combustion chambers in any manner that best serves the overall design. Best overall designs would use a combustion chamber that wraps around the hot rotor case ring – but chamber designs for best practical operating characteristics must be developed first.

"... Since the velocity of steam from a boiler, or air from a compressor is low until it reaches the nozzle, can it be bent many times before it loses energy, thereby allowing for a more compact engine?"

Using compressed air or steam is not as efficient as direct combustion.

4) "Why bother trying to start the turbine at rest? Can’t you just spool it up with an electric motor – or by hand? This would then eliminate the need for any features on the rotor designed to enhance very-low-end torque for starting. Because turbines run more efficiently when left at a single, constant rpm in the first place, why try to make it start & stop at will, like an electric motor?"

The outer washers also help to recover from loading the engine. When the rotor speed decreases to 50% of the fluid speed it stalls, so the outer washers are necessary to recover from high torque loads.

5) "... If I expend the time and energy required to build a small turbine, I’d feel better if I could justify it by having it perform some moderately useful task (i.e. I need an excuse). Any suggestions?"

12/18/02

Robert L O'Brien Jr.

OBILASER@aol.com 

Subject: combustor

Sorry it took so long to respond. I haven't lit my combustor with a chamber on it yet... I did run the fuel manifold and injector assembly as a torch, but now that I've got a combustion chamber it starts to get dangerous. Take a look at the attached photo and I'll explain what I'm trying to do.

The combustor is basically a pulse jet with a pressurized fuel/air injector. The injector is a ball type check valve. The fuel manifold is stuffed with stainless steel wool. This helps to homogenize the fuel/air mixture but most importantly it is a flame arrestor. The injector has a linear flow rate from 0.25 SCFM @ 10 PSIG to 1.5 SCFM @ 60 PSIG. The combustion chamber has a volume of 57 CC's (3.5 CI). The intended mode of operation will be: 

1) Turn on air
2) Start ignition (five 1mS pulses every 20 mS)
3) Bring up fuel pressure

First, I would like to state that the text area supplied for posting these comments is too small. That having been said, I think this sight is absolutely fantastic! I especially appreciate the recent trend towards empirical study and comparison. It is a very good thing that you are willing to challenge your own beliefs about the Tesla turbine. Moreover, no one can point to your site and say that you "deify" Tesla in any way. But, I digress. Here's what I really want to talk about =)

I recently remembered hearing something that seems perfect for what you guys are doing. A friend of my father's was developing a prototype vehicle called the "li'l bugger". I don't know what became of it, but the concept was very ingenious. Essentially it was a lightweight, three-wheeled frame upon which a rather bulbous fiberglass body was mounted. It was powered by a 40hp industrial motor, designed to run at a more-or-less constant RPM. Now, here's where it gets interesting: Instead of transferring power to the wheels by a conventional manual or automatic transmission, the designer used a continuously-variable torque-converter from a Cessna or other light airplane. The result sounded rather like a table saw chomping into a large piece of plywood. BUT, it was quick! The torque converter allowed the 40hp industrial engine to run at it's optimum efficiency 100% of the time, because the velocity was controlled by the transmission. Thus, it had all the starting torque it needed, yet retained the ability to cruise at speed with the utmost efficiency.

I know that it's not quite time to build a Tesla-inspired vehicle. However, when the time comes, you are going to have to think about the drive train. Most people seem to think that a turbo-electric drive train is the only way to travel; I disagree. Every time you convert energy from one form to another, you lose some in the process. This is unavoidable -- and with a hybrid drive system, you do this twice! Not to mention that the motor/generator and batteries will add tremendous weight to the car. Instead, I suggest a purely mechanical solution -- a torque converter. There will be some loss of energy due to slippage of the mechanism, when compared to a manual transmission, but I think this will be offset by not constantly spooling the turbine up and down. Not to mention that the slippage will be greatly reduced once the vehicle is moving at speed, and the inner and outer halves of the torque converter are spinning at relatively the same speed. Some provision should be made for spooling the turbine down to an idle when stopped, or when crawling in slow traffic...it doesn't make sense to run the turbine at 100% power ALL the time. In addition clutch might need to be employed to allow for starting the turbine.

Which brings me to the second thing I wanted to talk about. I have seen that the Tesla uses round washers to aid in starting. Is it really necessary that a turbine BE self-starting? Electric starters could be used relatively easily up to a certain RPM. I only say this because it seems that boundary-layer effects are greatly minimized by the use of star-washers, winglets and such. It's not as if axial turbines used in aircraft and power plants don't use starter motors. So, for the sake of empirical evidence, it might be interesting to see what effects starter motors have on engine performance, and whether or not they negate the use of impulse-driven features.

Some gas turbines in powerplants use water injection to regain some of the power. I assume – correct me if I'm wrong – that this recovers some energy in the form of thermal expansion as the water absorbs excess heat. This produces still higher gas pressure, and serves to cool the combustion chamber, water having a very high heat capacity. If this is true, then I'm sure that water-injection could help to develop incredibly efficient combustion chambers. Thus, because I've heard almost no mention of it, I have to wonder if there's a big problem with water injection that I don't yet grasp. If so, what is it?

The last thing I wanted to add had to do with using a non-Tesla compressor unit for your first self-sustained turbine project. Forgive me if you are already moving in this direction, but it seems like it would be much easier to adapt vacuum cleaners, hair dryers, and leaf blowers to this purpose than to start from scratch. I don't think that current designs make Tesla pumps the best compressors.

Water injections is being used by some Tesla turbine developers to boost efficiency and lower operating temperatures in the disk pack. Both Tesla's experiments and recently posted experiments -- on our Club forum -- show a definite increase in overall operational efficiency when using round washers or blades in conjunction with the boundary layer effect of the plates. And yes, we are considering the use of bladed blowers/compressors in complete turbine designs.

12/22/02

Dan White

ufoengines@hotmail.com

I'm looking for people into hi-voltage experiments and pushing the boundries of what's possible in science. My father is working towards building an experiment to harness electrostatic and electromagnetic forces to produce lift, and god willing, a usable vehicle that might someday do away with rockets.

Thank you very much for answering my e-mail. It's a great help for us. In Europe nobody seems to be interested in Tesla turbines and very few information is available. Only in the library of the technical university of Vienna I found some articles from W. Rice, S. H. Hasinger. One article I am intrested in is from W.Rice at the Teslasymposium 1991 in Belgrade where he stated, that an isentrop efficency of 95% is possible. Do you know someone from whom I could get this paper?

I still hope that we realise a TT in our research projekt and thus I am thankfull for any information that support the TT. If you know someone in Europe who is working on TT please let me know or you can give him my adress. Thanks again.

Private e-mail.: klaus.engelhart@surfeu.at 

DI Klaus Engelhart 
Univ. f. Bodenkultur e-mail.: klaus.engelhart@boku.ac.at 

Hi. My name is Mehmet. I'm from Turkey. I'm studying marine engineering. I need some details for gas turbine. And steam turbine. Could you help me please? How can I take it. Or if is possible you can send my e-mail. Thank you. 

E_MAÝL: MehmetCullu@hotmail.com 

I have recently built a prototype, compressed air, model Tesla turbine. It is laser cut from 0.093" acrylic and has a 3" rotor diameter. It will turn 25,000 RPM freeload using ~3 CFM @ 20 PSI. It will turn a model aircraft propeller (8" x 4") at 6,500 rpm (direct drive) or 10,500 rpm (2:1 gear reduction). This equates to ~120 watts.

I have used this model to test and develop gas injector design and I am on to the next level.

Thanks for the reply. I am looking for some actual "math" of the design. I have changed the original Tesla design and want to crunch the numbers. I am currently going through some SolidWorks tutorials while I get quotes from laser cutting places to see how the design is doing. I am planning on letting the blades "draw" water into the turbine while I am injecting the pressurized hot gas (saturating the hot gas with water, should also cause the water to change states and turn gaseous). You mentioned that Tesla had 80psi for 18" discs, what was the temperature of the steam? (600 degrees C ?)

_____ Original Message _____

I am working on a 12" blade design and looking for design calculations for different types of fluids. I am looking at high pressure, low temp steam, but I don't know where the trade-off's should be. Thanks

Congratulations on your 'Most Bang for the Fuel Buck' article which I have read with great interest. You have certainly been busy over the summer months. HOWEVER! -- I guess you have probably raised a lot more questions than you have so far answered, especially for those of us who are eager to start 'cutting-metal'.

Are we going to get more detail information on how to construct the pyro-catalytic converter? Can the burner be built as a 'pan' burner suitable for underfiring (say) a monotube or firetube boiler or should it be a single nozzle burner? Can the burner be used in conjunction with water injection to eliminate a boiler altogether?

I am sure there are many of us who just want all the info. you can give us so that we can pursue our own avenues of research for everyone's benefit in the long run without having to re-invent the wheel.

Some have questioned how a divergent nozzle can accelerate a jet. The secret is in a work expansion. We can best understand this by reference to a simple Otto cycle engine. An air-fuel mixture at room temperature is drawn into a cylinder and then compressed. It takes work to compress the mixture. This work (energy) is stored in the mixture as heat and pressure. The higher the compression ratio, the greater the overall efficiency of the engine. But if the mixture is compressed too much, the temperature will ignite the fuel before the proper time. When the piston reaches its highest point, the mixture is ignited. (Actually the ignition is started a little before the highest point, but this is a simplified explanation.) When the fuel burns, the temperature of the mixture (now called combustion products) rises much higher. Because the temperature is higher, the pressure is also much higher. The piston is now allowed to go down. As it goes down, the high pressure pushes against the piston, doing work. Since the work (energy) is coming out of the mixture of combustion products, the temperature of the mixture goes down, along with the pressure. So by the time the piston has reached the bottom of its stroke, the temperature has gone down from perhaps 1200 degrees of 1600 degrees (f) to perhaps 250 degrees or 300 degrees (f). The heat energy that was in the mixture of combustion products has been transformed into mechanical energy of a moving piston that turns a crankshaft to do useful work. (Of course the cycle is completed by the piston pushing the combustion product out the exhaust so it can draw in a new mixture of air and fuel.)

In the same way, a nozzle can do a work expansion on a gas. If the nozzle is simply a hole, the gas will expand, but no work is done. The gas coming out of the hole will be a little cooler than it was, but only because the pressure now being lower, the gas becomes cooler.

But gas cannot flow efficiently through a plain hole. For efficient operation, the inlet side of the hole must be rounded. the exact radius of the rounded edge is not important, as long as it is at least about 1/3 of the hole diameter. If the nozzle is so rounded, the gas will pass through it at efficiencies of 95% to 98%. Any gas will pass through such a nozzle at the speed of sound, providing the pressure drop across the nozzle is at least about 40% of the upstream pressure. So a convergent nozzle will pass gas to the atmosphere at the same speed, whether the upstream pressure is 35 PSI or 10,000 PSI. (Actually, there would be a small difference in the speed of sound, so the speeds would not be exactly the same.)

The gas pressure in the nozzle will be about 40% of the upstream pressure. If the upstream pressure is about 35 PSI, then the nozzle pressure will be atmospheric, or 14.7 PSI. But if the upstream pressure is, say 200 PSI, then the pressure in the nozzle is still about 120 PSI. This leaves a lot of energy still in the gas.

The energy still in the gas can be changed into work by putting a divergent section after the convergent section. If the passage the gas is going through becomes larger, the gas expands. As it expands, it gives up energy. That energy will be changed into work. If the nozzle can move away from the gas, the work will be put into the nozzle. But if the nozzle is fixed, the work is put into the velocity of the moving gas stream, so the gas is accelerated to a supersonic velocity.

Now comes the fun part. If the piston in a piston engine moves down at a speed greater than the speed of sound, the piston will outrun the pressure wave of the expanding combustion product. In this case, the gas cannot push against the piston, and no work is done.

In the same way, if the convergent portion of the nozzle expands too fast, the gas cannot expand to the edge of the nozzle, and no work is done. But is the nozzle expands too slowly, there is unnecessary friction between the gas and the nozzle. So designers carefully calculate the ideal shape for the nozzle.

But there is a way to skip all the fancy calculations.

A nozzle does not have to be round. It will work almost as well if it is rectangular. This makes it possible to make an adjustable nozzle. Take two rectangular bars and bend one end of each into a generous radius and then bring the radiused end back so the two bars together make the outline of a chamber with a convergent-divergent nozzle. Put these two bars between two steel plates, with oil and lapping compound. Carefully lap the two bars between the two plates until they are completely polished all along the edges touching the two plates of steel. (In doing this, it is important to keep the steel plates parallel. Lapping the two bars at the same time is an easy way to keep them approximately parallel.)

When the two bars are finished, fasten one of them between the two plates. Then put the other bar between the plates, with adjusting screws at the smallest section and at each end. Use the adjusting screw at the entrance end to clamp the section tightly against the fixed bar. (A flexible sealant will be needed here.)

Then the screw at the smallest section can be used to adjust the size of the nozzle and the screw at the exit end can be used to adjust the nozzle expansion.

The correct setting for the smallest section can be determined with a pressure gauge. (For this I assume you are using a source that can deliver pressurized gas at a certain rate.) The pressure just upstream of the nozzle will drop when the nozzle is too large. So adjust the smallest portion of your nozzle to the widest opening that will keep the upstream pressure at the output pressure of your source.

The ideal setting for your exit be determined with a thermometer. The gas gets cooler as it does the work expansion, but it does not cool in a non-work expansion. So adjust the nozzle exit until you find the setting that gives the lowest temperature in the exhaust gas.

While this device will allow you to experimentally find the ideal dimensions for your nozzle, it probably will not be very practical in your finished machine. So use the dimensions from your test to design your finished nozzle. Remember that the behavior of the nozzle is dependent on the area of the passage, not the width of the passage, so if you use a round passage in your finished nozzle, you will have to convert the rectangular areas into circular areas.

Without a drawing, this may not be very plain, but I do not have a way to send a drawing right now. This is my (I suppose) patentable invention, but I hereby release it into the public domain.

My name is Gerd, I'm living in Portugal. I came on your page through an article about the Tesla turbine. I agree with you about your view of the petrol mafia and the urgent need to stop them and their criminal acts. The only way to be able to do so is to work together on all social levels and with all people of the world willing to create alternatives. And one of the most important points within these activities is without any doubt the energy production and distribution question.

One of the crucial points in this area is the question of energy storage to allow a continuous electricity delivery to the grid. Hydrogen is the selected medium to solve this problem. Secure storage containers already exists (metalhydrid) as well as retransformation units (Fuel cells burning Hydrogen/ direct combustion with Tesla Turbine?) I wondered why you did not mention hydrogen as an alternative for all automotion processes too!?

But beside the technical solutions there is although the urgent need of an international interdisciplinary discussion on this subjects to come to practical solutions for the urgent needs of humanity to avoid further wars and continuing struggles to secure the rich part of the world energy needs.

One practical step towards this aim could be to open an international discussion on all technical aspects, with the objective to prepare a practical proposal to the World Social Forum that will happen in January 2003 in Porto Alegre / Brasil. We know both that the energy question has to be solved to create a real alternative to the criminals who are governing at the moment, playing the rich worlds police and using their power against the interests of the whole worlds population to defend their profits. If we are able to put together our ideas and join our efforts we will be able to do a lot in this direction to stop them!.

Hi, love the TT pages you've got. I've been thinking about a TT based generator and am curious about a couple of things.

1. I'd like to use solar vacuum tube collectors to vaporize liquid at ground level and condense it at say, 5 feet up. The condensed liquid would be caught in a tank which leads to the TT inlets. Outlet is downwards to the evaporation tank. The entire thing happens in a partial vacuum, to lower boiling point. Have you heard anything about a very low pressure TT? (I'm not even sure what PSI is generated by a gallon of water at 5 feet is at this point... this is very preliminary thinking!)

2. The scenario above calls for a sealed system, what do you think of a TT that lies with rotors horizontal, the "output" shaft rising into a pocket of air and spinning magnets (rare earth) that provide a connectionless coupling to an external generator.

A few months ago I emailed your club looking for the formular for torque for a Tesla turbine. Recently I found the info on a website "howstuffworks.com" which stated Horsepower = Torque x RPM / 5252. So therefore, Torque = HP x 5252 / rpm. This info helps to understand performance of TT.

I have been scrounging around the web finding anything I can in regards to TT's. So far I am convinced that this is a real good idea to develop. Very cool principle of operation but me being a EE I am missing a few things that help me to understand the concept better.

For the TT to achieve the theoretical ideal efficiency it has to go through a series of RPM of lower efficiency. During this low RPM state the flow over the disk pack is reacting with the surfaces it touches and should (theoretically) be a turbulent flow at low rotor speed, move to a transitional flow at moderate speed and ultimately be laminar once it achieves ideal efficiency/low slip (please anyone correct me if I am wrong, suggested reading would be great too). My question based on the above assumption is what is the fluid that would impart the most energy to the rotor? A hot fluid or a cool fluid (assume water to be the fluid for this question)?

In my mind the cool fluid would have the most effect on the rotor because its density would be higher thus providing more boundary layer energy exchange.

Being a pilot and having a near fanatical fascination with turbines I recently came across the Tesla Bladeless Turbine. Having so far only heard of the "classic School of turbines" I at first was a bit skeptic, until I stumbled over your site and now I am hooked. One thing I find particularly interesting is the paper turbine by Samuel Falvo. Is there any better way to demonstrate the efficiency of this design?

Hi, did you know that a bunch of California kids in the 1970's basically started the computer industry by sharing information something like this?

In response to sgtjato@aol.com  who wrote the following:

At first I was getting 7000 to 8000 rpm and I was experimenting on different ways to maximize the turbine performance and duty cycle, because the whole thing was becoming too hot. So I installed a 30 deg fan type jet nozzle that shoots pulses of atomizes water next to the rotor, thinking this will cool down the turbine. Well it did cool down the turbine after the water turned into steam and sent the turbine to 16 000 rpms. The wonderful thing is that now I run the turbine for hours and it won't go higher than 180 Celsius.

This concept is not new. This has been used ever since turbines were in use, especially since high-temperature metals were not common back in the 1800s and early 1900s.

09/15/02

Robb

r_greathouse@yahoo.com

Subject: Has anyone built a Tesla power generator?

I have been designing a steam driven TT during this year and had almost reached the stage of cutting metal when I literally stumbled across your website. What bliss! – apart from your excellent presentation there are real practical issues being discussed as opposed to some of the more ethereal writings I have managed to find up to now.

I am now having a radical re-think on certain aspects of my design and would like to ask a few questions –

a) I am intrigued by the winglets on the discs and follow the logic behind them but do they significantly increase the noise of the turbine?

b) Have you undertaken any further tests to evaluate the best profile and angle?

c) Is there any data correlating steam consumption/torque/disc dia.?

My design has been based around a steam supply of about 350psi with minimal superheat in order to keep the dynamic viscosity as high as possible. The original idea being to use a Doble type monotube boiler, oil fired. However, having read about Luis Mendonca’s experiments with pulse combustion and the possibility of using water injection into the combustion chamber to produce steam I am keen to follow up this avenue of research. I have tried e-mailing him but so far without a reply.

Can you point me in the right direction to find out more information about this form of combustion and how to make one.

Incidentally, my reason for wanting to build a TT in the first place is to use it in a 1/5th scale miniature locomotive, which is my particular interest. I need to achieve a shaft HP of about 25HP and my design uses 23 x 145mm dia. discs at 0,25mm spacing.

I stumbled on your web site while searching for info about the Tesla disk turbine. I'm not an engineer but I'm fascinated by the principle and have been wondering if it would be applicable to a human-powered boat (HPB). I enjoy tinkering with things and have built 2 variations of HPBs, one using a 12 ft. catamaran with bike crank set driving dual paddle wheels, and the other a mono hull with outriggers with the same drive setup. I want to achieve more speed and thought that I would investigate whether the water jet concept could be simulated in a HPB. With the right gearing I can achieve 300-400 rpms at the output. Is the Tesla turbine concept feasible for this situation or should I stick to more conventional methods like a prop? I've also considered the Gorlov helical turbine.

Hello and thank you for the time and effort you have put into the web site! I am in THE snowmobile capital of the world, Alaska, and am wondering if you can direct me to a laser cutting source with stainless stock.  I will be in Michigan to visit family in the "lower" Winter Wonderland and would like to bring back some stock to begin experimenting with.

My interest is in electrical generation using steam using 1800 rpm standard generators.  So I have to figure out what disk diameter is going to be appropriate, or if I should gear down?  I didn't want to have to either gear down or have 10kW generators built for 3600 rpm.

My intent is a 10kW  generator.  I am supposing a proportional or servo nozzle valve will control frequency nicely.  Any input will be greatly appreciated.

Thank you for your comments and your interest in my achievements. It's nice to know that I can be of some help to you and I like to share my knowledge and experiences to fellow TT builders. As a fellow scientific or rather technologist, I'd like to tell you that the following comments are not to put down or to discourage your research in anyway...but rather to provoke some brainstorming and to find new solutions.

Okay ....here we go.

Steam vs. hot gas for efficiency... Without any doubt steam is an efficient way to provide fluid power to the rotor and is almost instantaneous and it will cool down the whole of the turbine and will boost torque of a factor of 70+... BUT...making steam is not a very efficient way of providing velocity because of the calorific transfer... In fact you will use about 10 to 15 per cent of the fuel burn to provide steam. This is because water needs to store energy before changing state. In my testing for a fuel to power efficient turbine I noticed that it was impossible to achieve more than a 82% efficient turbine using steam. Mind you this is still better than a gasoline engine and has no pollution residue because I use alcohol as fuel. By the way burning alcohol already produces steam since it always contains waters.

(Pure alcohol contains at the very lest 2% of water... I use 72 % alcohol which has 28 % water). I noticed by using only hot gas I can now reach higher revolutions thus increasing efficiency... But the turbine does slip more easily at high load... which means I have higher HP but lower torque.

Here are some secrets of the Tesla turbine I know that work.

A) Like you said!!! Don't re-invent the wheel... The genius Tesla has tested this turbine for more than twenty years and others have also tried and never could improve on it. My opinion on the design is stick with it... although now a days we can use better materials.

B) Your winglet concept... Grant you that at lower rpm you will reach better efficiency and it will turn longer after thrust stop, but I think this is a major flaw... Because weight is your major enemy at very high rpms... Of course at low rpms you get a good efficiency rate because the discs slip a lot... meaning that the rotor doesn't flow with the rate of gas flow... It's working on friction. At high rpms the disc rotate almost at the same speed as the gas flow (adhesion) so your winglets won't have any effects but create more load at the rim of the discs and might cause them to warp or even tear.

C) Rivets should never all be aligned... Distribute the weight of the rivets symmetrically throughout the rotor so that the load of the rivets is distributed evenly throughout the rotor.

D) I use 1/32" thick disk in st.st. 316L (surgical steel) spaced at 1/16" apart. Why 316L??? Because of the low carbon contained in the steel and the high temperature attained in the turbine. Dimensions are relatively the same as Tesla used...But I guess he wished 316 was of his time. Actually my disks are tapered as his 10000 hp turbine he made, meaning the center of the disk is 1/16" but tapers off at the end to 1/32. I don't use spacer washers... since my disks are tapered, a depression is machined in the disk to allow exhaust.

E) Bearings: Never use grease bearing or fully enclosed bearing... Use high speed bearing that use light oil or oil spray. ( if you can afford them, use magnetic bearings or air cushion bearings).

More to come soon... Remember that those discs will spin at almost the same speed as the gas speed you providing. So keep the weight down if you don't want any surprises. Coming up ...my flame holder for the 3000 psi combustor, the nozzle and injectors and some diagrams.