Overcrank Single Cylinder Engine

[tel]

ONYA Brian, perseverance wins out in the end! Thm:

 

[metalmad]

congrats Brian
she's a goer!!
Well done mate
Pete

 

[kcmillin]

Great job Brian, she looks and runs great!

Kel

 

[Maryak]

Congratulations. It's a very attractive engine.

Now that it's done you have an opportunity to spend some time learning how to tap small, blind holes.

When you break a small tap, regrind the tip into a bottoming tap if there's enough meat left to do that. (If not, just make a tiny boring bar out of it.)

Great tips Marv,

Now, if only I could control my temper long enough so that I don't throw them as far and as hard as I can, somewhere in a 360o arc. :

Best Regards
Bob

 

[larry1]

Great looking engine, very smooth runner. larry

 

[Harold Lee]

Brian,

WOW!!! What a nice running engine. I love the built up flywheel. You should feel a great sense of accomplishment!!!

Well Done.

Harold

 

[Captain Jerry]

Brian

That's a nice looking engine and as you said, lots to look at.

I have been trying to locate other examples of that mechanism but other than Stew's well documented wall engine prototype I can't find any. All of the other engines that I can find that are called "overcrank engine" use a very different design that use a forked or double connecting rod with a crosshead guide that is an extension of the piston rod beyond the point where the connecting rod pivots. I can find several excellent models of engines built on that plan but except for Stew's engine and your engine, I cannot find no other engines where the crankshaft is located between the piston and the "small end" of the rod.

I think that the design is very interesting and I would like to see other examples. If anyone can point me to other examples of an overcrank engine with at reversed connecting rod, I would love to see it.

Thanks for showing this build and for the detailed drawings.

Jerry

 

[Dan Rowe]

Jerry,
This arrangement saw service as a naval engine in the 1860-1880 time frame. On this side of the pond they are called back acting engines in the UK the type is sometimes called a return connecting rod engine. Several of the gunboats in the US Civil War were equipped with back acting engines including the CSS Alabama and the USS Kersage. There is to my knowledge only a single example of the naval version of this type still in existence. It is at the US Merchant Marine Academy at Kings Point NY.
http://files.asme.org/ASMEORG/Communities/History/Landmarks/5539.pdf

Dan

 

[mzetati]

Here is the official 'Cleaned up' video.

Nice engine, glad to see it finally working.
And a special thank You for the "VIDEOOFVALVEOPERATION.mp4" I found on Your photobucket folder: I did not know I could test the works of piston/cyl./valve that way, before having completed an engine.
Marcello

 

[lazylathe]

Excellent stuff Brian!!!!

Love the motion of those overcrank engines!!
Lots to keep the eyes busy!!!

Congratulations on another fine engine and build!!!

Andrew

 

[tel]

Jerry,
This arrangement saw service as a naval engine in the 1860-1880 time frame. On this side of the pond they are called back acting engines in the UK the type is sometimes called a return connecting rod engine.

Dan

Yeah, 'overcrank' is a bit of a misnomer and means, as far as I know, something quite different - ie an engine with the crankshaft mounted above the cylinder!

http://www.brunell.com/uploads/html/GEORGINA_OVERCRANK_ENGINE_136_1.htm

http://littlemachineshop.com/products/product_view.php?ProductID=4246&category=

 

[ozzie46]

Excellent build and documentation. A very fast build as well. Seems like it just started and its done!

Ron

 

[Captain Jerry]

Dan and Tel

Thanks for the clarification on "overcrank". I could not see any real advantage of this mechanism over the conventional mill engine configuration except that it is slightly more compact but the additional complexity did not seem to be worth the difference. As a marine engine, a "back acting" configuration makes good sense because it lets the engine lie athwartship and keeps the shaft on centerline with better weight distribution. Now it all makes sense.

Jerry

 

[tel]

Adding to the confusion, of course, is the overlap in terms that also occurs. What Brian, and Stew before him, have built are what I have heard called 'side rod' engines - not to be confused with the 'side beam' engines, such as mine, which could also be accurately describes as an 'overcrank'.

Mind you, I think the engine that gave Stew his inspiration was correctly described, it's just that the folk who have it on display mounted it upside down. 'Wall' engines such as that were most often done with all the scary moving parts mounted up out of the way - the operators lost less arms and legs that way.

 

[Brian Rupnow]

Well, whatever it is that I built, I certainly enjoyed it!!! ;D ;D ;D

 

[hopeless]

and WE certainly enjoyed the build as well Brian :bow: :bow:

chuck

And thank you for putting the plans in the public domain :bow:
It was a great thread as always from you
Pete

 

[SBWHART]

Mind you, I think the engine that gave Stew his inspiration was correctly described, it's just that the folk who have it on display mounted it upside down. 'Wall' engines such as that were most often done with all the scary moving parts mounted up out of the way - the operators lost less arms and legs that way.

I think you've made a very valid point their Tel, how the original was displayed never sat easy with me, they had it slung from a girder with a solid drive pulley with brammer belting.

I think they needed an engine for the display and found this one and used it the best way they could, I would really love to find out some more information about the original who made it and how it was used, when I made enquiries at the museum all they could tell me was that it was a steam engine :-\ . I can't help thinking that it would have been ideal for mounting in a small traveling crane, as it us nice and compact.

Stew

 

[tel]

Well, whatever it is that I built, I certainly enjoyed it!!! ;D ;D ;D

As well you should have Brian, not only a nice engine, but some nifty problem solving along the way - can't ask for much more than that!

 

[Brian Rupnow]

I have read the article posted by Dan Rowe, where it points out that the "back crank " style of engine was used in ships, to more or less equally distribute the weight of the engine on each side of the crankshaft to keep the ship from listing to one side.
That makes a great deal of sense to me. As I was building this engine, I couldn't help but think that there seemed to be a lot more "mechanism" than would be required to simply operate a small industrial mill.--Even in the UK, real estate wasn't that important that it required saving two or three feet of engine length.

 

[Dan Rowe]

Brian,
As these engines were used on naval warships the other consideration was to keep the engine below the water line. The Ranger was a sailing ship with an auxiliary steam engine. The aiming points for cannon at the time were the mast or the water line of the hull. The whole engine is below the water line and in relative safety from cannon shot.

I was at the Admiral Nimitz Museum at Fredericksberg TX and there is a large photo of the Ranger on the wall. I was surprised to see a well known ship to me as I was cadet at USMMA. Chester Nimitz was a midshipman when he served on the Ranger.

Dan