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1. Most small scale steam engines will run on very little pressure with no load. Some simply by blowing into the intake pipe.
2. I can not see where the inventor has reduced the parts count - a "normal" steam engine has a piston/Flywheel/Connecting rods etc. In this case he has 2 pistons & cylinders, An extra flexy rod that must absorb some power as well as complex joints that move and pass steam.

3. I can not see how this arrangement is more compact - if you remove the boiler most steam engines are very compact unless toys and a turbine even more efficient and compact.

No I am afraid it is interesting but not the solution to the worlds energy problem.

I have to agree with MrH. To steal his format:

1) This design has a lot of moving parts. The flexy rod is constantly moving and, more importantly, deforming. The cylinders themselves are in motion. All that energy has to come from somewhere. In a traditional reciprocating steam engine, only the pistons, pushrods, and crank move. This is a good thing.

2) I can't see scaling his technology up to anything of useful size. One of the reason this thing works is that all the moving parts are lightweight and small because of scale. Once it gets bigger, everything will become relatively heavier (due to scaling) and the masses will matter. The vibration and motion of those cylinders will be important. The large deflections the flexy rod will cause fatigue problems. All those complex articulated joints won't hold up as well either.

These are really good comments, and reveal my relative ignorance about engines -- although a lot of what you both are saying is just good mechanical sense (when ya think about it).

I'd love to hear how the builder would respond. Maybe I can get him over here.

I sent Roger Green email about this item and discussion...

Isn't a turbine the most efficient way to use steam, only one moving part?

I love seeing people making a twist on something old. Maybe it's not better than traditional piston engines, I dunno... maybe it will someday? I dunno, but worth exploring a bit don't you think? Just the fact that he approached it from a different angle is worthy of a make blog post! I applaud Mr Green for thinking outside of the box, and able to pull it off!

It's just so mesmerizing to watch....

I was really curious how this thing was going to operate, and suspected something fishy when there was a mention of an animation of it... what could possibly so interesting about the movement of a steam engine?

Besides everything else the above has mentioned (which are all completely valid), wouldn't this engine just rattle itself apart eventually? There doesnt seem to be a counterweight providing any balance to the lateral rotation of the system being made possible by that nice flexy-tube-shaped thing in the center...

It is all very nice that the author states that is efficient, but what does this mean? Which size engine achieves which efficiency?10%? 20%? 99%? 100%? (we all have heard this recently ;-)
Without this information the site is useless. What should I buy a licence when I don't even know the key technical parameters?

I fail to see the problem with having a flexible rod as part of the design. Sure it takes energy to deform it, but that energy is later returned to the system. It's not like you're loosing anything here.

I read a few reviews on this, and it sounds like it's a death trap waiting to happen. If you build it be careful of the shrapnel when this thing tears itself apart. Anyhow, wouldn't it be easier just to make a Tesla turbine and vent steam through it?

The reason for the improved efficiency of this flex rod mechanism is that it produces intermittant straight line movement. There are no side forces as in a typical crank mechanism. This means that the cylinders do not require lubrication and the valves do not need a separate mechanism to operate. The pistons are sealed with "O"rings. There is virtually no wear. In a normal engine the pistons are either pushing against one side of the cylinder or the other causing friction. The flex rod mechanism does not take energy because it is like a spring that gives back as much as it takes when it returns. The purpose is to maintain alignment of the cylinders. A six cylinder uses the same number of crank bearings as a one cylinder engine (one). Because the engine is not made from large castings,it looses far less heat. The glass cylinders do not conduct heat like metal. One of these engines has been made that produces 800 HP. It is very light-weight and requires far less steam than a normal engine. It is also very cheap to build. The engine that is in the plans(a DIY version) may be assembled in five minutes. The exhaust is pure distilled water without any contaminants. The water can be recycled back to the boiler without gumming up the boiler with minerals and oil.
Turbine engines require high volume superheated steam. The vanes have to be changed often at great cost. My engine runs on saturated steam that operates on very simple and safe boilers that usually do not have to be certified. A Tesla engine produce very little torque and is high mantenance. The small green engines run 5000 RPM"s and up. None have come apart. The reason is the straight line movement. Your concern about this is unfounded in fact. There are many hundreds of these engines in use all over the world. I have never heard of one flying apart. There are three companies that are in the process of manufacturing this engine in different forms and sizes. You will see them on the market soon. I doubt that they would want to manufacture something that flies apart. Regards, Robert Green

$45 is a bit steep for the plans, and a Tesla turbine has one moving part. Where's the high maintenance? Sorry, but the flex rod thingy looks like an accident waiting to happen. Hence, why it's not used in modern engine.

Where is the Tesla engine being manufactured? About the one moving part that Tercero is referring,- that's the part that goes.The blades burn out in a flash. Steam is very corrosive. What makes you think my engine is not being used? What accident is supposed to happen with the "flex rod thingy"? Those flex rods are used in heavy industry every minute of the day. 360 days a year at thousands of RPM's per minute.

Tercero: Tesla turbines are neat, and really easy to build, but wouldn't they be pretty inefficient? It seems to me there'd be a ton of energy lost in that boundary layer. A traditional reaction turbine should be more efficient, at least at its design speed.

I'm building a Green Flexrod engine for a friend it's rubbish as are the plans and claims. Complete LIES re 800hp engine and 5 minute assembly.

This engine would be more interesting if it was a stirling engine? Water and Fire are limited resources. Energy should not compete with food or water.

The supposed adantage of the Tesla bladeless turbine over reaction turbines is that the Tesla design does not require superheated, high-pressure dry steam. For the hobbyist/tinker this is a real bonus, as it decreases the likelyhood of a catastophic failure in the boiler and associated plumbing.

I think it's brilliant. We need more people like this who put forward new things - that's the only way progress is made. Constructive criticism is good, but those who just posted negative unfounded comments appear a little jealous...

It's amazing to see how those who can't do it easily criticize those who have done it.

Has anyone out there built one? I would like to hear from them.

I think the draw of green's steam engine is that it supposedly works on relatively low prssures...20 psi! That's about what a pressure cooker gets to.

Quote "It's amazing to see how those who can't do it easily criticize those who have done it.'
It's amazing to me that those who don't have a clue about the technology are always the most fervid supporters.
To repeat the claims are rubbish, the plans are rubbish and I wish I'd never offered to make the damm thing. If you don't have a lathe and a silver soldering rig, you cannot build the unit. There is a huge amount of stuffing around required.

Well, as a matter of fact, I have made two of these engines. Yes, both of them required fine tuning but, worked beautifully after some TLC and deicated tweaking. Bottom line, either your heart is in it or you are wasting your time and ours for complaining about something that you haven't followed through with.

Robert has improved on his plans and construction ideas. As a result his engines appear even better. No! I have not built one of them yet but I probably will in the near future.

It's more fun excerzing my mind and making it work than working my jaw muscules and complaining.

Pretty cool that the inventor posted here. But, I have searched for and wide for one single other person who has built the green steam engine... I have yet to find any pictures on any other website then the inventors.

I have also heard that the engines are being mass produced by a big company. That was about a year ago.

Now... From the videos, the engines appear to work.

What kind of joint are the pistons connected to that allows them to swivel around like that? The joint would also have to hold pressure. I don't think I see it on the inventors website in the "harder to find" parts section.

Snoopy22,
Is there a way I can contact you?
I have the plans in my hand and I'm hoping you can answer some questions.
I would ask Robert but the fist rule is don't bombard your guru with a bunch of stupid little question, save him for the big ones.
Please don't take that statement to mean your not a guru ether. ;)
I seem to have to much time and to much money!

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