Making Progress

Blimey, when you wound up the speed I was expecting it to explode in a cartoonish shower of bits!

Very smooth.

Rod

when you wound up the speed

It took quite a lot of RPM to get it to start walking. And even then it was still quiet and smooth.

And it seems it only took about 3 weeks to build and paint! Amazing.

Just out of curiosity, which particulr vibrations make a model steam engine walk, and is the walk direction different from vertical to horizontal engines? I guess the point of tethering (air/steam line) may also play a role. My guess is the main source of vibration is the piston, but I can see the full answer being quite complicated.

For your next project Jason, is there perhaps a machine that Cherry Hill missed?...only half joking there

Ches

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Looks like I'm going to have to run it up again and get the tacho out so see what speed it needed to start levitating

I think one reason this one stays fairly well grounde dis that unlike the cast original which would likely have beed hollow I left the base solid which dampend any vibration.

I suppose the counter balanced shape of the crank web is there mostly to counter the in out movement of the conrod, cross head, piston and piston rod but will add some up and down imbalance as the speed goes up. The verticals seem to want to jump about a bit more whether that is due to the moving parts or simply the fact that they have a smaller footprint and tend to be a bit more top heavy I'm not sure.

Build was spread over about 5weeks looking at the dates of the photos, I don't tend to start writing up a build until the engine has been test run. I do tend to have a few projects on the go at once and would have been painting and assembling the James Coombes when I started making this one. And while this has been getting painted I managed to get another engine that has been sitting about for a while completed and test run.

While I was taking the photos of the Progress replica I thought I would take a quick group shot and video of the three Stuart replicas. They have all been quite enjoyable quick builds fitted in between larger projects and are all good runners.

Jason,

Thanks for the feedback on vibrations and timescales - good stuff.

I wonder if also, sometimes a resonance is found and it all kicks of after that. My 10V seems to be OK up to a point and then it fairly quickly decides it needs a walk after a certain rpm is reached. My Beam stays put in spite of how many rpm I try to throw at it, but that is possibly due to the high mass, which was one of your earlier points.

I wonder if any of the original full sized engines ever suffered from resonances and how they managed that.....adding weights, stiffners etc?

Anyway, a very neat looking threesome that run a treat. Hopefully there is more on the way ie builds plus pics plus CAD info

Ches.

Getting a single cylinder engine to run without (much) vibration is not easy - and as you approach perfection, extra parts need to be added. Balancing bits that just go round is easiest - flywheels etc just need to have their centres of gravity in the middle of the axle. Anything that goes back-&-forth requires something else which goes forth-&-back in the same time, and on the same axis. It can be done, but books have been written about it. Incomplete books ...

Cheers, Tim