Model Doxford opposed piston engine

[bytewise]

I have been helping restore tools and machines at the Connecticut Antique Machinery Association museum in Kent Ct. While searching for a project I might build I ran across information about the Doxford opposed piston engine used in ocean going ships. This seemed to be an interesting possibility. I am retired and have accumulated a few antique machine tools. They include a pre-1900 vertical mill, an Atlas lathe, a Hendey 14x6 cone head lathe, and a B & S horizontal mill with a dividing head. I also have available welding equipment. All the tools have been repaired and restored to good working condition.
I searched the web for information about the Doxford engines and found many postings with history and bits of technical information. In 1914 the William Doxford Co. started research on an internal combustion engine for ship propulsion. From 1914 thru 1920 they built and tested a single cylinder opposed piston diesel engine. In 1920 they started producing engines for installation in their ships and for sale. The engines were quite successful. They produced many hundreds of them over the next 40 years. Unfortunately, there are no complete drawings available for any of the early engines. I wanted to make a single cylinder model rather than multiple cylinders just to minimize the number of parts I would have to make. I did find enough pictures and drawings to make the project possible.
I obtained a CAD program and a wide paper printer and have started designing and drawing details of the model. I have chosen to make a 1/10th scale model of the early one cylinder Doxford engine. I plan that it will be a functioning diesel engine, running in either direction. I know it is an ambitious project. So far I have not found any ‘show stopper’ problems.
I have made about 50 drawings so far and estimate that I am one third to one half ways done with design work.
Depending on the responses to this post, I will post progress information from time to time.
Hugh Ross, Dutches county, NY

[J Tiers]

I can totally agree on the engine being a cool subject for a model. I like it, and if I ever do an engine model, the Doxford is on my short list of interesting subjects....

1/10 size seems still pretty darn big, though..... less of a model, and more of the size of a standard Lister engine........... big enough to get a credible injection diesel action. Diesel injection is another of those things that do not seem to scale well...... darn physics gets in the way!

Here is a link to some info and lots of picture links. The site in the link gets boos and cat-calls around here, but so what? Info and cool pictures is good.

http://www.practicalmachinist.com/vb/antique-machinery-history/photos-big-machining-processes-doxford-sons-c1950s-181722/

[uncle pete]

For sure a very cool subject. Ring sealing, compression ratio, crank, rod, wrist pin strength and building a working mechanical fuel pump and injector are going to be tough. It's certainly doable though. I'll go do a check and I think I can come up with a link for a U.K. site where there's pictures posted of a full working single cylinder diesel engine far smaller than your thinking of building.

I found it, try http://modelengineeringwebsite.com/ True_diesel.html

For me and using Google, it's an extremely slow site to load. The site owner has very good taste in what is posted on his site though. It's well worth searching around on it.

I just tried my link, it won't take you to the direct page, it will take you to the site, then click on features, 14th down on the left column is the link for that diesel engine.

Pete

[bytewise]

Thanks for the comments. I have seen the PM posts and the Doxford museum site. I have searched the web extensively and found many bits and pieces of information scattered about. The most detailed information I found was on the ‘https://www.oldengine.org/members/di...ord/htm’ site.
My choice of scale was influenced by two factors: one, small enough that the parts would fit my machinery and two, large enough that I did not need a jeweler’s lathe. I am not comfortable making very small parts.
The specs of my model are 1.5 in. dia. Cylinder, 6 in. combined stoke (3 in. each piston), comp. ratio 22:1 or higher (subject to fine tuning later), compressed air start. More info later as work progresses. Hugh

[Dennis WA]

Hugh,
Good luck with your project. Alfons Verheijden a member here is a retired marine engineer who is a mine of information on Doxfords. If you have not already had contact with him, then may I suggest you do so.
Dennis

[bytewise]

Thanks for the ref. I have already been in touch with him.

[J Tiers]

That engine is the "link of the month", clearly.....

The Hansen diesel is about as cool as possible.....20mm bore and 40mm stroke IIIRC.... the volume is so small that the needed fuel per stroke is only a "trace", and getting that atomized well enough so that there is no smoke is pretty amazing IMO.

Not to mention the general workmanship, which is top notch and suitable for a museum. In the video when he picks up the oil can that could sit on the end of your finger, and starts pushing the microscopic feed button as he oils the sight feed oilers......... it emphasizes the actual tiny size of all of that perfectly made stuff all over the engine..... ai! weh ist mir....

This should get you straight to the article

http://modelengineeringwebsite.com/True_diesel.html

[uncle pete]

J Tiers,
Thanks for the correct link that works. Glad you enjoyed that. Yeah getting all that to work reliably at that compression ratio is quite the accomplishment. And to get it to run that slow and without any exhaust smoke like you mentioned!!! Even building a flyball governor that does work at that small size is no easy task.

Pete

[Alfons Verheijden]

L.S.
In the past I have seen DOXFORD advertisements in THE MOTORSHIP, where a pencil stood upright on the DOXFORD frame, just to accentuate how perfect the balancing was
Can anyone help me on a picture of that advertisement
Many thanks in advanve
ALFONS