Elbow Engine

[Mark EasingwoodParticipant @markeasingwood33578]

This is the second engine I have made, it was completed in around July 2025, but I have only just got around to photographing & videoing it.

I used the information gleaned from Mr Stewart Hart’s post on the HMEM forum, and an old “Popular Mechanics” article from 1965, as the basis of modelling my own version in Alibre Atom. I used the same basic sizes, but fabricated the base/standard to look more like a casting.

Not everything went perfectly first time, I re-made one cylinder as the drill grabbed in the Bronze and damaged the bore, it was usable after reaming, but not really good enough, so I made another, I have since learnt that it is better not to pilot drill bronze, but to use the final size drill, after spot drilling.

My attempt at silver soldering the fabricated standard also failed, not a big enough burner and a cold windy day is my excuse. After peeling the rim from the standard, (it was certainly soldered in some places!!!), I made a new rim and stuck it together with JB Weld.

The flywheel is also fabricated with a steel rim, and aluminium “pepperpot” centre.

As this engine is based on a constant velocity joint, (I read that somewhere!), and not a “Real” engine I have painted it using two colours of metallic paint.

It runs nicely on 68 grade slide-way oil, in either direction. It doesn’t seem to like thin oil, is a bit messy to run and uses a lot of air.

Link to Stew Hart’s engine. HERE.

Link to Popular Mechanics article at bottom of this Wikipedia page. HERE

Alibre Atom Modelling.

Finished Engine.

 

I also filmed the engine running for a YouTube Video, which can be found, HERE.

(Embedding YouTube videos does not work when I try, it just crashes the page, when i click submit)

Mark.

[JasonBModerator @jasonb]

Nicely done and the “cast” look cetainly sets it apart from the othet barstock looking ones I have seen. Can’t blame a cold windy day as I have just been doing a crankshaft but a small burner is the most likely cause of your problems not only giving too little heat but even if it did get to temperature the long heat time can exhaust the flux.

I sorted the video for you. Click “share” under the video, copy the link an djust paste it into a post.

[Mark EasingwoodParticipant @markeasingwood33578]

Thanks Jason.

I need more practice with a blowtorch!!

I posted the long code copied from “Share-Embed-Copy” into my post, then when I clicked submit, I got an error message informing me that I do not have permission, then the contents of my post vanished.

[JasonBModerator @jasonb]

You don’t need to use the embed url, just the one that comes up as default nect to copy.

[Mark EasingwoodParticipant @markeasingwood33578]

Thanks again Jason, I will try that for the next one.

[DiogenesParticipant @diogenes]

Nice engine, Mark – I like the detailing on the standard and base, looks and runs a treat – thanks for the links.

[Nigel Graham 2Participant @nigelgraham2]

A lovely piece of work to a very intriguing design!

I think I prefer seeing it ticking over nice and gently, as a “full-size” one might have done (were they built?) as that shows the rather unintuitive and slightly hypnotic action much better.

Thankyou Mark!

[Mark EasingwoodParticipant @markeasingwood33578]

Thank you for your comments Diogenes and Nigel.

Nigel, I don’t think any full size ones were built, I read somewhere that it is a design based on a Constant Velocity joint.

They are certainly mesmerising to watch, and being well balanced are capable of a fair turn of speed.

 

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