# Rotary Engine Design



## vederstein (Nov 23, 2012)

For some time I've been wanting to design a "steam" engine that runs like a WWI Gnome rotary (e.i. the crankshaft is stationary and the block rotates).

Several years ago I was partially successful with a two cylinder design.  Anyways, I've become much more accomplished since then.

I've finished a design for a five cylinder version.  In my CAD software, it looks like it all works out.  I plan on building this this winter, but attached are the plans if anyone would want to review, improve, and/or build it.

I've deliberately left off material types because you can use whatever you feel looks good.

--ved. 

View attachment Con Rod Hub Assembly.pdf


View attachment Crankshaft Assembly.pdf


View attachment Engine Stand.pdf


View attachment Piston Assembly.pdf


View attachment Rotary Engine on Stand.pdf


View attachment Spacer.pdf


View attachment Block Assembly.pdf


View attachment Connecting Rods.pdf


View attachment Cylinder Head Assembly.pdf


View attachment Engine Assembly.pdf


View attachment Engine Assembly-parasolid.zip


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## mnay (Nov 29, 2012)

Great idea.  I have had similar thoughts, my version was going to feed the air or steam from a ported back plate rather than through the crankshaft.

Thanks for sharing you work and ideas.  Looks like a fun project

Mike


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## vederstein (Nov 29, 2012)

Thanks,

I'll actually start building it in early 2013.  The progress will be shown here.


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## mnay (Dec 4, 2012)

I have been looking at the drawings.  Again thank you for sharing them.  
 I just see a hole through the crankshaft and assume that is the steam/air inlet.  How does the engine exhaust?

Thanks
Mike


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## vederstein (Dec 6, 2012)

There is a port on each cylinder at the bottom of the piston stroke.  The pistons are single acting and the engine is kind of a uniflow design.


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## popnrattle (Feb 4, 2020)

that is so cool Vederstein!
here are videos of a rotary and a recip. that i designed and built. sorry, I don't have any plans.


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## peter2uat (Feb 5, 2020)

Looks like a fun project !
could you please add the stroke of the engine into the crankshaft assembly drawing.
I could print it to dimension and glue it to a blank shaft, but with detailed numbers it will be definitely better...
Thanks
Peter


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## vederstein (Feb 5, 2020)

Peter,

Actually I can't update the drawings.  That CAD software is long gone.  (I did this years ago).

I highly recommend you look over my build log on this engine.  These plans had some significant design errors.  The uniflow design just simply didn't work and I had to remake the crankshaft with a larger diameter so that the crank had both pressure and exhaust ports.

Unfortunately, the design as presented here will not result in a running engine.  After my "on the fly" modifications it's one of my best runners though.

...Ved.


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## peter2uat (Feb 6, 2020)

found it - 3/4 by 1"
I remember having seen a similar arrangement on a 3 cylinder compressed air engine, just have to find it....


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## Richard Hed (May 20, 2020)

popnrattle said:


> that is so cool Vederstein!
> here are videos of a rotary and a recip. that i designed and built. sorry, I don't have any plans.



Well I want your to know, I watch this just to listen to the music, thanx


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## Mr.McKinney (May 21, 2020)

vederstein said:


> For some time I've been wanting to design a "steam" engine that runs like a WWI Gnome rotary (e.i. the crankshaft is stationary and the block rotates).
> 
> Several years ago I was partially successful with a two cylinder design.  Anyways, I've become much more accomplished since then.
> 
> ...




Hi Ved, 

That's a cool little unit.  I've never looked at an air engine before.  Looks like Solidworks. Any chance you could upload a Pack & Go of the assembly?  The assembly file won't work without the part files.

File --> Pack&Go --> Save to Zip File

Thanks...

E


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## vederstein (May 21, 2020)

I've long lost the files.  Sorry


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## Mr.McKinney (May 23, 2020)

No problem.  Thanks for the reply.


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## davidyat (May 26, 2020)

*Echesak,
   Go to this site, I found the plans for the 5 cylinder rotary from Vederstein:'





						Five Cylinder Wobbler Plans
					

I guess I just could have just made one of the existing designs for the "hula" engine, but I went ahead an designed my own.  If for no other reason, this just shows that there's more than one way to design the same outcome.  So if anyone says something is the "wrong way", well screw them.  I...




					www.homemodelenginemachinist.com
				



I was over at his place yesterday and we were making some aluminum castings for his current engine. I was asking him about the rotary and he was saying, I believe, that there are mistakes. Anyway, here they are.
Grasshopper*


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## vederstein (May 26, 2020)

Correction:

The design for the Hula engine is good.  I'm not aware of any issues that that set of drawings.

The rotary engine (Rotary Engine Design) is the one with design issues.


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## glue-itcom (Oct 1, 2021)

just made a video of my rotary air engine to try and explain the idea. This also shows the conrod just rotating about a fixed point


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