Introduction: Tin Can Stirling Engine

How I built a hot air engine almost entirely from junk.  I've wanted to build one of these ever since discovering stirling engines in about 2003.  Spending the weekend making things in Steveastrouk's workshop gave me the opportunity to make the precision parts I'd need, and I knew most of the engine was going to be made of improvised materials, so decided to see if I could make the entire thing out of scrap or unwanted materials.

If you aren't familiar with how Stirling engines work, there are plenty of resources online- the Wikipedia page is a good place to start.

Step 1: Design

The "core" of a gamma stirling engine of this design is a large cylinder that holds the displacer, connected to a smaller power cylinder providing the power strokes.  I decided to follow Darryl Boyd's "walking beam" design, where the power cylinder sticks out of the side of the dis[placer cylinder, because it suited the materials I had and it looks cool  :)

I found that an aluminium drinks can would fit neatly inside a steel soup can, so decided to use that for the displacer on the grounds of being cheap, light and easy to work with. The steel soup can provides a sturdy body for the engine and also meant I could ake the bottom removable to allow maintenance.

I found some decking to use as the base, some 1" x 1/2" pine to use as supports for the moving parts, and a piece of 3/4" aluminium strip to use as the beam.  The engine is a messy combination of metric and imperial units- that's what happens when you use scrap materials!

Step 2: Bill of Materials

Displacer cylinder

Two empty steel food cans, at least one with a tapering bottom

Displacer

An aluminium drink can that fits closely inside the soup can without touching the sides
Two thin metal discs (eg lids from food cans)

Power cylinder 

Copper or brass pipe, as round as possible, around 40 - 50mm long

Power piston *

Flywheel

A low-friction ball bearing
A CD or other disc to use as the wheel
Pennies for weights

Beam

About 12" of metal or wood thick enough not to bend too much

Frame of engine

Thin wood (1" x 1/2" or larger) for supports, at least 24" (600mm) long
A piece of plank at least 12" long and 4" wide (300 x 100mm) for the base

Other

Thin brass tube 1/8" inside diameter and steel rod 1/8" diameter- about 12" of each (the precise measurement of these isn't as important as the rod being a snug sliding fit inside the tube)
Wire coathanger
Two terminal blocks
JB Weld or other high temperature epoxy
Fast-setting epoxy (eg Araldite)

Necessary tools

Hacksaw
Power drill
Wood saw

Desirable tools

Rotary tool with grinding and cutoff bits

Step 3: Power Piston

There are several ways of getting a power cylinder and piston for your stirling.  At one end of the spectrum, you can buy graphite pistons and glass cylinders online.  This guarantees you will get good quality parts but feels a bit like cheating :)  At the other end of the spectrum, you can attach a rubber membrane made of a piece of balloon over the end of the cylinder, like scraptopower's engines.  This is probably the easiest to make but limits travel and introduces friction.

Others have made pistons by casting JB Weld inside their chosen power cylinder. You can read more about that here- I didn't do this because I had the machined piston/cylinder combo, but it seems to be quite a popular method.

The piston is a 20mm x 20mm solid cylinder with a 1/8" hole bored in one end.  A short section of steel rod was glued into the hole, and a section of brass tube glued over that.  The end of the tube was flattened and drilled to 2.5mm to accept a conrod made of coathanger wire.  In engine terms, this is the small-end bearing.

Step 4: Flywheel

The flywheel is a wheel that I think came from a VCR.  I used it because the bearing ran smoothly and the wheel looks quite nice as a flywheel :)  The axle hole for the bearing was conveniently almost exactly the size of the brass tubing I had, so that would work for an axle. 

I initially tried gluing a short piece of brass tubing to the surface of the wheel to act as a crank, but the glue bond between the metal surfaces was weak and kept breaking.  Drilling a small hole into the wheel and gluing a piece of coathanger wire into that made a much stronger crank.  A piece of wood with a short section of brass tubing fixed into a hole drilled through it provided a support for the flywheel.

Step 5: Displacer

The displacer is a section cut from an aluminium beer can, with lids taken from other cans glued over the ends to make a flat-ended cylinder.  This made the displacer air-tight, so to avoid the risk of it pressurising and exploding in the engine I made a small "breather" hole with a needle.  The top end plate was drilled in the middle and a section of steel rod glued into it.  The steel rod I had is a sliding fit in the brass tubing, which offers low friction but an almost airtight seal, so was ideal for the displacer rod seal.

The length of the displacer is important- it should take up about two thirds of the space inside the cylinder.  I worked out how far the crank on my engine was going to move (the "throw", about 20mm), and subtracted that from the length of the displacer cylinder (90mm) to find the largest size the displacer could be (70mm).

I actually glued the rod into the displacer with it inside the engine once I had assembled the displacer cylinder to make sure the two lined up- if everything was measured with sufficient precision this would be unnecessary.  I used JB Weld for this join as fast-setting epoxies tend to soften at high temperatures.

Step 6: Displacer Cylinder

To make the displacer cylinder, I cut the bottom off a can with a can opener which removes the entire end of the can.  I then cut the bottom two inches off another can of the same size with a tapered end, which I could force into the first can to form an airtight seal, but which could be removed if I needed access to the inside of the cylinder later.

The top of the displacer cylinder was drilled in the centre and a section of brass tubing glued in with JB Weld to form the displacer rod seal.  A hole large enough to accommodate the power cylinder was cut into the side using a rotary tool and the power cylinder glued in.

When assembled, a short section of brass tube was glued onto the end of the displacer rod, flattened and drilled like the power piston to provide a joint for the beam conrod.
I also cut out the bottom of a tuna can and glued that around the top of the displacer cylinder to use as a water jacket for cooling, but this was actually less effective than plain air cooling, and developed a leak that was letting water into the cylinder so I removed it.

Step 7: Connecting Rods

The conrods are made of coathanger wire.  Where a joint is only required to rotate a small amount these are simply 90 degree bends in the wire fit into 2.5mm holes, with a dab of hot glue on the end to keep the wire in place.  Where the conrods make a continuously rotating joint (where the power piston and beam conrods attach to the crank on the flywheel) these were made of drilled brass pieces from a section of "terminal block" electrical connector.

These are a very convenient size and shape to join the end of a piece of wire perpendicularly to another piece.  One of the screws was removed and a hole drilled sideways all the way through the brass, and the other screw used to clamp the end of the conrod in the connector.  I got this idea from reukpower's Coke Can Stirling Instructable.

The conrods all have a Z-shaped bend in the middle which allows for length adjustment by tweaking the bends.

Step 8: Framework of the Engine

Before building anything I drew a diagram and worked out the necessary dimensions of the engine so that nothing would collide, then dry fit all the pieces before cutting and gluing.  The base is made from a piece of scrap decking.  The beam is a 250mm section of aluminium strip with a hole drilled for a pivot in the middle and two smaller holes near the ends to accept the conrods.  The beam support and engine support were made of more pine, screwed into the base.

Despite working out all the dimensions beforehand, my apparent inability to drill a hole straight through a piece of wood coupled with my cheap wobbly power drill resulted in a certain amount of trial and error being applied to the placement of the engine parts. 

Step 9: First Run!



In case the video embed doesn't work, the first run video is here on YouTube.

Step 10: Design Tweaks

After the engine had run successfully, I addressed some of the issues that had become apparent.  The flywheel support wasn't in quite the right place, so the piston conron was running at an angle creating excessive friction on the crank.  The flywheel itself wasn't really heavy enough to sustain rotation of the engine, so I added the CD and pennies to give it more momentum.  The beam and flywheel tended to wobble on their mounts slightly so I added some spacers on their axles to keep them in place better.

After all these mods, the engine runs more reliably than any fuel source I have to test it with :)  It will run at approximately 150-200rpm on a decent candle flame, and has run at nearly 500rpm when I accidentally overheated it slightly with a large meths burner.  The engine is mechanically sound at that speed- my concern is the displacer overheating and the epoxy that keeps it attached to the rod failing.

Comments

author
Sang GenerasiM (author)2017-06-04

Nice bro....
Thank you for sharing

author
DIYWEAPONS (author)2016-03-03

Excellent!

author
TravisM18 (author)2015-11-03

that is great. I like the themo acoustic engines. The hard engine to make is a rotary stirling with a rotary displacer and a thermo acoustic heating tube.

author
T0BY (author)2015-06-23

This is a great project! You have done particularly well to make it mostly from scrap.

author
wmada (author)2015-05-31

Hey thanks for this instructable. I have a really cool idea which I dont want to reveal intil I build it and I will post it. I am curious if this can handle a load. Do you know or have you tested what this design can handle?

author
PKM (author)wmada2015-06-01

It can handle a load. Just not a very big one :) I connected the flywheel up to a DC motor running as a generator, and running the engine at full power it was just about able to light a red LED. That's an electrical output power of about 50mW, and if we assume a candle flame outputs 75 watts of heat the efficiency is 0.07%. For generating electricity you'd do better with a Peltier/Seebeck module over a tea light candle.

In terms of mechanical power, it's pretty bad as well :) a very small torque will make it stall, so you'd need lots of reduction gearing to get a usable torque out of it but I'd guess that (say) mounted on a model train carriage it could propel itself at a quarter of a mile per hour.

My setup was certainly not optimal and you could get more power out of a similar engine with more attention paid to impedance matching, having the right stroke length for the engine and so on. Plenty of people online have powered LED flashlights and radios from
tin can stirling engines, getting a few hundred milliwatts out of an engine with a similar (or simpler) design.

author
ShailP (author)2015-01-24

do u put anything inside the can??

and how much time does it take for the engine to start running??

author
Electrospark (author)2014-10-27

Well explained instructable! :-)

Thanks for the info!

author
AATHIS (author)2014-05-09

hey what is the difference between displacer cylinder and displacer,?
thnx for your help in advance

author
assasinsareus (author)2014-03-05

LOL!!! Put down your handbags guys.

As far as I am aware Sterlings are used today in pretty much all modern nuclear submarines to help generate power from the heat of the reactor. Think of the heat differential between a nuclear reactor and the depths of the sea!

I think a big factor behind the lack of practical sterling engines is that they are largely unheard of by the general public something which the internet and youtube is now helping along. I also know that some manufacturers have tried and failed to install them into cars as early as the 1940s, probably due to the problem with ramping up the power you get from them. Mainly caused by the fact they will run at a steady rate and accelerating / decelerating can be tricky.

Now a sterling vs a solar panel is an interesting match and I wouldn't be surprised if over the next 10 years or so we start to see some really nice green generators based on Stirlings coming out. Especially when petrol and diesel start to become so expensive that they become no longer feasible for the general population.

author
eyesee (author)2013-01-10

Piston seal problem

author
jeveda12 (author)2012-12-20

can you explain a little more about this engine, like how to build the piston and why there is to pistons.how this works please

author
PKM (author)jeveda122012-12-21

Step 3 links to some ways of making pistons- you can make one out of glue, or a balloon, or (the way I did) machining it out of metal. I'm not good enough at machining to write a guide on how to do that, so I skipped over that part.

There is only one piston, which has to be a very close fit in the small cylinder but slide freely, and the displacer inside the engine which needs a small gap around the sides. To understand how the engine works I'd suggest reading the Wikipedia page about them. Briefly, the displacer is there to move air around inside the engine, and the piston is pushed in and out by air pressure.  This explains why the parts need to fit the way they do, but to understand the entire cycle you should read more about Stirling engines- there is plenty of information on the internet about them.

author
lonely164 (author)2012-09-12

good

author
asdasd (author)2012-09-01

Cool, but I'm not sure is it stirling.

author
PKM (author)asdasd2012-09-01

Well, as I understand it this engine uses the Stirling cycle (heat, expand, cool, contract), so I think it is. What part are you unsure about?

author
deep92 (author)2012-01-15

I get that for the power piston to be able to move, it has to be smaller in diameter than the power cylinder, but the thing that i don't understand is that if the piston is smaller than the cylinder won't it cause air leakage??
thanks for ur response! This is the only thing thats bothering me, otherwise i'm really looking forward to making this!!!

author
PKM (author)deep922012-01-27

That is the biggest problem with building solid power pistons, they have to move freely but fit very closely. Mine, thanks to a very big lathe, is smaller than the inside of the cylinder by something like a quarter of the thickness of a human hair...!

Unless you can make the cylinder and piston perfectly smooth you are aiming for the best compromise between it being too loose (and leaking air) and too tight (and friction taking power away from the engine).  I believe loose is generally better for a hand-made first engine. How you do this is entirely up to you, there are a number of possible approaches- check out the many other Instructables on stirling engines.

author
yokozuna (author)2011-11-24

Nicely done sir, 5 stars.

author
ravenheart_tinkers (author)2011-04-26

Very cool little project. Thanks. Oh, and Sterling engines have enormous real world application without any further development. They already work so they aren't just "curiosities". These engines are highly efficient (and they are also typically used with free or very cheap energy sources anyway) and very low maintenance & cheap to operate. Without any further development whatsoever, these engines are already available for purchase from numerous sources, especially relating to electricity producing solar concentrators and co-generation applications where new or existing heating furnaces & incinerators are fitted to also produce electricity. Co-generation engines are not only available for large commercial applications, but also for residential and small commercial applications, requiring as little as 500 degree Celsius to operate. Comparing petroleum diesel engine applications to sterling engine applications is utter nonsense. Diesel has absolutely no application where sterling engines are designed to be used. These applications are specific to producing very cheap electricity, so implying that diesel generators could somehow be used is ridiculous. I strongly suspect the poster makes his living from either petroleum or combustion engines and is making a feeble attempt to misinform. Now to be fair, algae generated diesel may be something to show enormous promise in the relatively near future with some further technological development, but petroleum based diesel is a non-argument. And even having given a nod to algae generated diesel, it doesn't appear that it will be cost effective enough to produce anytime soon to render sterling engines obsolete. Note: Hebinho posted some relevant links above in regards to this argument for anyone who missed them and would like to see just how advanced sterling engine technology already is and what it has to offer.

author

it's hard to make a sterling really work but when it works it shouldn't stop working

author
Barfight76 (author)2011-06-16

Excellent work! I want to build one using clear materials (i.e. glass, pvc, etc.), but I can't seem to find what kind of hot temperatures that are dealt with. The pvc specs I'm looking at have a max temp of around 150 deg F. My question really is, what kind of temperatures are you getting from your hot air portion?

author
charris7 (author)2011-05-29

can someone please explain the power piston and cylinder to me? what do I need, and how do i position it to make it work???

author
PKM (author)charris72011-06-01

Someone else has probably explained the cycle more concisely than I have, but in essence:

The displacer pushes the air in the engine to the hot end, where it heats up and expands. This expansion pushes the power piston outwards, because it's the only part of the engine that can move to let the air inside expand. The power piston moving outwards turns the rotating parts around, which moves the displacer and so moves the air inside the engine to the cold end. The air cools down and contracts, and so sucks the power piston back inwards.

The power piston itself needs to be able to move in the cylinder freely, but also to move in the cylinder with a change of air pressure. The simple way to do this is to just glue a cut-out circle of balloon rubber over a hole in the engine, so it will move in and out with changing air pressure. I did it by making a smooth brass tube and a piston to fit very closely in that tube.  That way is more fun and can make a more powerful/efficient engine but needs workshop tools whereas the balloon method might only need a knife and some pliers.  Check out reukpower's instructables for more on how you can build stirling engines without precision engineering tools.

author
Hebinho (author)2011-02-27

Hi juanvi,
just go to YouTube and search for KS90 and you will see some nice examples!
They also start running when the upper surface of the displacer cylinder is being heated by just letting the sun shine on it!
But they are a bit difficult to align and when building one, you have to avoid everthing which could cause some unneeded friction.

author
pfred2 (author)Hebinho2011-02-27

When I was there they seemed to be rather commonplace items today. Stirling engines are at best a curiosity though.

author
Vengence (author)pfred22011-02-27

Wrong. Currently they're more efficient than solar cells. They can be up to 40% efficient(not the type in this instrucable though). The company Stirling Energy Systems Inc. has been contracted to build a solar farm in California...

author
Hebinho (author)Vengence2011-02-28

First of all we should distinguish between "toy" or "demonstartion" stirling engines and real serious stirling engines! Scottsdale's Sterling Energy Systems Inc. is running the "Suncatcher" which has a mirror dish of 11.5 m diameter and produces 25 kW of eletric power at an efficiency of 31.25 % (world record in 2008), while solar cells rarely are getting beyond 15 %!

Europe has a lot of CHPs (Combined Heat and Power plants) installed, using biomass to generate heat and electrical energy in housing areas, based on stirling engines. Of course these engines by no way can be compared to the ones you will find at instructables.com, but these are real hitech products, running 30,000 hours and more needing only a small amount of maintenance.
There are small CHPs (15 kW heat and 3 kW electrical energy), just take a look at http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=home.showFile&rep=laymanReport&fil=LIFE99_ENV_D_000452_LAYMAN.pdf

Hungary based FlexEnergy is builing a generator (38 kW output) running on landfill gas (methane) only.

Now you can continue to state "...Stirling engines are at best a curiosity though..."

author
pfred2 (author)Hebinho2011-02-28

Thank you for allowing me to continue stating the obvious.  A few obscure projects referenced does not make you right. There is likely more steam piston engines still in operation than Stirling engines today.

A 40kW diesel generator isn't newsworthy, its a pallet item.

http://www.google.com/images?um=1&hl=en&safe=off&tbs=isch:1&&sa=X&ei=s7FrTY7PPIO88gaU4LyQCw&ved=0CC8QBSgA&q=40+kW+diesel+generator

About 153,000 results ...

I think we need to distinguish between fantasy and reality but that's just me.

author
Vengence (author)pfred22011-02-28

[pfred2: A few obscure projects referenced does not make you right.]
Yes, it most certainly does. It's called proof, and it's not an opinion. You have been proven wrong.

[pfred2: There is likely more steam piston engines still in operation than Stirling engines today.]
Of course there is. Steam is still one of the most efficient and most powerful systems there is. If there wasn't a problem with steam production and storage we'd still be using them in our cars. You're not making a case for yourself. How exactly do you think nuclear power plants work? That's right...steam...

[pfred2: I think we need to distinguish between fantasy and reality but that's just me.]
I guess the sources that Hebinho mentioned are fantasy and not reality? I don't think "we" need to distinquish between fantasy and reality, I think just "you" do.

You may now continue to post opinion...

author
pfred2 (author)Vengence2011-02-28

You just keep on believing that efficient equals practical. As an example fusion is amazingly efficient, just not very practical. Nuclear power plants do not use pistons except to raise and lower the control rods. But yes turbines are fairly efficient, and practical as well.

No I'm not making a case with you! Because you are an unreasonable individual.

I'm supposed to accept a few sources but it is OK for you to ignore the overwhelming number I present? At this point I really don't care what you think.



author
Vengence (author)pfred22011-02-28

[pfred2: As an example fusion is amazingly efficient, just not very practical.]
Fusion isn't even done at a stable level yet. Once fusion reactors are perfected it will be extremely practical and will take the place of current nuclear reactors. You're still wrong in your example.

[I'm supposed to accept a few sources but it is OK for you to ignore the overwhelming number I present?]
Overwhelming number of what? You have produced zero evidence that "stirling engines are at best a curiosity".

author
pfred2 (author)Vengence2011-03-01

Sure it is it, just takes more power to operate than can be gotten from it. If fusion reactor engineering impossibilities are ever overcome I'm sure it'll rain pennies from heaven on that day!

Here are 153,000 examples

http://www.google.com/images?um=1&hl=en&safe=off&tbs=isch:1&&sa=X&ei=s7FrTY7PPIO88gaU4LyQCw&ved=0CC8QBSgA&q=40+kW+diesel+generator

That took all of a tenth of a second for our favorite search engine to cough up but you conveniently choose to ignore. Go argue something you've a chance with like extra terrestrials or the Easter Bunny. That ought to be a good one, least you'll have baskets pretty soon as proof!

author
Hebinho (author)pfred22011-03-01

@pfred2:

This discussion is getting pretty ridiculous!
We are not discussing about something like "Perendev motors" or "Overunity", we are talking about a kind of technology, which is existent and which is being developed more and more (due to the fact that the so very much easier way to use petrol-based technology will by the best meaning of the words "run out of fuel" in the not so very far future. Would you do a little more research in the internet, you would find, that actual Striling engines have an efficiency (fuel input to mechanical output) which is at least as high as modern Diesel engines (internal combustion).

And concerning your "impressive number" of  Diesel generators: how many of those are really "green", having a particle filter and using an additive like "AdBlue"? Don't tell stories by quantity, switch to quality!

author
pfred2 (author)Hebinho2011-03-01

I never said any of them were green just practical to the point of burying Stirling engines. Which everyone knows are just a curiosity.

author
Hebinho (author)pfred22011-03-01

Just another case of practical use of Stirlings:

http://www.mackboring.com/CMFiles/Docs/Product_Brochure.pdf made by http://www.whispergen.com

Btw: When I experimented with battery-operated tubes in 1960,integrated circuits also were just a curiosity. SMD LEDs emitting white light and 1 W of power, nobody had an idea that this will be realized! Or do you really believe that the kind of camera module you will find in modern smart phones (1 sqcm incl. "flash LED" and 3 MP resolution) could have been dreamed of in the early seventies?

For the last decade the rule has been, that technological knowledge at university level has doubled every 5-6 years at an accelerating tendency.

Just wait less than a decade and you will see, what development Stirlings will go through. Or maybe someone really will show the proof of overunity engines .... ;-)

Greetz from Brazil!

author
pfred2 (author)Hebinho2011-03-02

Technologies with merit often develop rapidly as you point out. So I'm sure any time now someone will crack this nut of the Stirling Engine that has been around since 1816. Indeed the world waits with bated breath for the discovery of perpetual motion!

http://en.wikipedia.org/wiki/Perpetual_motion

Too bad they only work if you lubricate them with snake oil. But until such a day they are curiosities at best I'm afraid.

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komodoboyx5 (author)pfred22011-03-04

too bad your diesel generators only work if lubed up in oil, and run on dead ancient plants (which are running out, surprisingly)

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pfred2 (author)komodoboyx52011-04-07

Not in my lifetime they won't.

author
pfred2 (author)komodoboyx52011-03-05

Too bad you're wrong on all accounts.

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Vengence (author)pfred22011-03-03

[pfred2: Sure it is it, just takes more power to operate than can be gotten from it.]
No, it's not. You're basically saying so in the latter part of your statement. Will you ever stop being wrong(Apparently not)? It's not supposed to take a continual energy feed to keep the reaction going. It's only supposed to take energy to start the reaction, and it should keep going for as long as it's stable. You understand what stable means right? ITER is expected to produce a minimum stable reaction of 480 seconds but could be as much as 1,000 seconds, producing 5(on the low end) to 10(on the high end) times as much energy as was needed to start the reaction.

[pfred2: That took all of a tenth of a second for our favorite search engine to cough up but you conveniently choose to ignore.]
You posted the same exact useless link again? That's proving that stirling engines are a curiosity how?(I'll give you a hint: it's not) With the national average for diesel being $3.716 per gallon and some places as high as $3.964, tell me again which one you think is actually more practical? Do you have to keep paying the sun to receive and convert it's energy? A link to diesel generators proves nothing about stirling engines. You'd have to be delusional to think the diesel generator is more practical.

author
pfred2 (author)Vengence2011-03-03

What vessel besides magnetic do you propose plasma be contained in? It's not like you can put something a million degrees into your coffee cup you know?

You just choose not to see the relationship. They pointed out one example of a 37kW generator I pointed out 153,000 of similar in just one other technology. Now if diesel wasn't more practical then how come there are so many more examples?

author
SydAndy (author)pfred22011-03-06

pointing out existing examples means nothing about the future.

By the same example 100 years ago you would be saying coal powered steam engines were the only solution earth ever needs, claiming petrol engines were a fad.

100 years before that, you would be mocking anyone even thinking anything but a horse could move a cart.

You would probably also be saying that since 90% of carts were drawn by horses, that those carrying heavier loads which required bullocks to pull them should be regarded as imaginary?

author
pfred2 (author)SydAndy2011-03-06

Maybe what you say would be true if Stirling engines hadn't been around almost 200 years already.

author
Hebinho (author)pfred22011-03-07

And for how long the wheel has been around before becoming ball bearings ....?

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pfred2 (author)Hebinho2011-03-07

That explains your problem. You have axles in your bearings!

author
Vengence (author)pfred22011-03-05

[pfred2: What vessel besides magnetic do you propose plasma be contained in? It's not like you can put something a million degrees into your coffee cup you know?]
It's starting to seem like when you're wrong on one part of a subject you try to bring the attention to a different part, hoping you'll eventually be right about something. Don't change the subject. Where's your proof/argument that current fusion reactors are stable(self sustaining for a significant period of time)? Is this you conceding defeat?

[pfred2: Now if diesel wasn't more practical then how come there are so many more examples?]
How about I answer your question with more questions? If diesel is more practical, why are there more gasoline engines on the road today? Why are hybrids just now being sold when the technology necessary to develope them has been around for at least 30 years?
The reasons are political, not reasons of practicality...

author
pfred2 (author)Vengence2011-03-05

I thought we were talking about generators in the 37kW range and there diesels are more more prevalent than gasoline ones. Though you can get plenty of gasoline generators in that range as well! Stating more facts that defeat a baseless argument is hardly conceding defeat. In court it would be called a preponderance of evidence actually. Though I suppose your only hope is that I am wrong about something eventually. Nice try, better luck next time. Hybrids are being sold now for the simple economic facts that enough fools believe in enough nonsense to shell out enough money for them. Nothing more.

author
komodoboyx5 (author)pfred22011-03-04

you're also ignoring the fact that diesel is a non-renewable resource. The sun will burn on for many, many, many, many, many, many, many more days. In fact, by the time the sun does burn out, we'll have found more suns to juice for energy.

& Don't argue the stupid position of proposing ethanol, that would require energy to make energy, wasting time & power.

author
pfred2 (author)komodoboyx52011-03-05

I'm not the one arguing.

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