Double Acting Oscillating Engine

[editor@glue-it.com]

Thought you might all like this. A video of my double acting oscillating engine. I designed and made it some time ago, but thought it might be nice to talk people through how it works along with the basic dimensions etc. Specs are listed on my double acting engine page:

I'm also trying to improve my presenting style for videos like this, don't know about everyone else, but it feels quite strange to me to talk to a camera.

[odd one]

Very nice. Did you drill the ports after it was all assembled to ensure accuracy on alignment or were you good on your calculations.

[mklotz]

Very nicely done indeed. You might want to have a look at how Elmer Verburg built his double-acting wobbler; his includes a reversing mechanism...

http://www.john-tom.com/ElmersEngine...rseWobbler.pdf

I built his design and it runs very nicely - a compact design suitable for use in an RC boat.



I share your discomfort with talking to an inanimate object. Talking to oneself makes folks suspicious of your sanity. If you have a pet, try having it in the room when filming and talk to it. At least you'll know that something is hearing what you say even if it doesn't understand.

[editor@glue-it.com]

Very nice. Did you drill the ports after it was all assembled to ensure accuracy on alignment or were you good on your calculations.

The calculations are quite easy as the ports are on the same radius for the cylinder and valve plate. Once I had those arcs I then constructed a line that goes through the crank pin (when it is at both extreme positions) and the centre of rotation of the cylinder on the valve plate. All of these points are quite easy to calculate.

If you look carefully at the exhaust ports on the valve plate you can see that I enlarged them, effectively allowing them to open earlier - so I guess my calculations weren't spot on.....

[editor@glue-it.com]

I finally got round to learning to use FreeCAD and making plans.



The 3D modelling of parts was actually quite easy using FreeCAD 0.19

There is quite a steep learning curve with this software and must admit that I found the Part > Body > Sketch logic difficult to get at first.

But stick with it as it does click, I'm coming at it in middle age and it's taken me ~3days of solid work to get to a point where I can design parts.

I have found the technical drawings quite tedious, it might just be my very low knowledge of CAD...



I have though created plans for this simple oscillating engine, ok, they are not free, but they are low cost.

[editor@glue-it.com]

The exploded assembly view of the engine, hopefully this gives you an idea of what an oscillating steam engine looks like as a bag of bits.



and as a simple line drawing



hopefully you can spot the missing bolts, spring and grub screw

[editor@glue-it.com]

Making this engine simpler has actually made it.