Stuart Compound Launch Steam Engine.wmv

This video shows the first tests of a new Compound Launch Steam Engine using compressed air. I made the engine from Stuart castings. It took about eight months to build.

The first part of the video shows the engine as it should look and sound in non-condensing operation. I have temporarily replaced the flywheel with a relatively heavy 3-jaw chuck from a Taig lathe to simulate the load of a large propeller in water. Of course it is not a perfect substitute, but it does give the effect. Ideally a propeller in a water box is about the best test condition,.

The second portion of the video is less exciting. I replaced the chuck with the proper disk flywheel. In this test the engine spins too fast for my old-style camera to follow. (I will try an HD video sometime in future, but at the moment things are rather hectic in my shop during these initial tests and not healthy for my newer cameras) The engine appears to be screaming away - just a blur - but it is only going barely double the speed of the previous runs. If you listen carefully and try to exclude the hum of the air compressor, you can just hear the ticking of the engine, sounding like a sewing machine going at a good clip. Don't fear for the engine - I won't wear it out - the speed is well within it's normal range.

I have had considerable experience with the non-compound version of this engine - the Stuart TWIN Launch. I installed one in my tugboat and although the boat is still unfinished, the engine has consumed many dollars worth of fuel over the last twenty-odd years. Although the two engines look nearly identical, there are differences: The Compound's valves are more difficult to set up after it has been constructed. Also it will be more efficient and run on less volume of steam, but at a higher pressure. I hope you have good speakers - it also has that lovely powerful pounding sound evident on the first portion of the video.

I noticed a most interesting thing when running the Compound on compressed air which proves there is expansion happening inside. The exchange pipe between the cylinders became so cold that it developed heavy dew on the outside, possibly even a little frost - it was ice cold to the touch. Of course the entire cylinder block was very cool as well, but not to the same degree as the copper pipe.

Please note that the engine construction is not quite completed in these views - temporary pins are holding the links to the reversing shaft, no insulation or lagging sheets have been added to the outside of the cylinder block and it is presently devoid of paint or other finishing touches.

The construction process of this engine is detailed on my website: www.ModelEngines.info

The link is near the bottom of the home page.

John

Category:

Science & Technology

Tags:

• Stuart
• steam engine
• compound engine
• compound launch

[MK216vTurbo]

It's great to see it running so good, well done, John. I wish my Twin Launch would look and run so great soon !

Olivier

[ModelWorkshop]

@MK216vTurbo Thank you Olivier - I will be looking forward to seeing your Twin Launch video here soon!

PS - I sent you more details by email yesterday -it sounds like you received it ok this time.

[ModelWorkshop]

I simply turned it on the Taig lathe Ray.  Check this page:

compound.modelengines.info/cra­nkshaft.html

[ray5961]

ok.. now that is cool! Nice work John!

[ModelWorkshop]

@ray5961 Thanks Ray! - there is still some work to be done on this engine before I can say it's finished.

[ray5961]

How do you make the crankshaft on something like that? Do you have a grinding attachment for one of your lathes, like what I have seen when I visited Sherline?