7 Cylinder Double Acting Steam Engine Complete

[crueby]

Here is my build of a 7 cylinder double-acting radial steam engine. It is not based on any real original engine, but is patterned loosely on the internal-combustion radial engines common on early aircraft. Being double-acting, there are 14 power strokes per revolution of the crankshaft, so it self-starts very easily, and runs at a fairly slow speed down to about 10 psi. For the video below, I had the air line from the compressor set up for 60 psi with a needle valve inline to control the air flow and speed, rather than adjusting the pressure regulator. I find this works much better, since if the engine gets under load or has a sticky spot and slows down, the pressure in the line goes up and gives the pistons a little more power.

The propeller for an engine this size would be quite large, and have to hang off the table, so in the interests of space and safety I put on a cut-down prop instead. It gives quite a good breeze even at slow speeds!

A couple pictures of the engine:





And here is a video of the engine running:
<a href="https://www.youtube.com/watch?v=qgd9PNxtx6E" target="_blank">http://www.youtube.com/watch?v=qgd9PNxtx6E</a>
Chris
 

[cnr6400]

Runs and sounds fantastic Chris! 

[wagnmkr]

Now that is just plain fun!!! That sound is so realistic!!!


Well Done That Man!

 

Tom

[Admiral_dk]

That was quick - even by your standard 

Looks good and runs well 

Per     

[PaulR]

Another amazing engine!

For some reason the motion of the crank connections doesn't look like I expected it to (dunno what I was expecting but there you go!). What are you doing about lubrication? I might have missed the answer somewhere in the build thread but you're making engines quicker than I can read about them 

[crueby]

Thanks guys! This was a fun build, went a lot quicker than I expected, but thats mainly due to production lining the steps on each part.
Paul, the connections for con rods and such are all stainless steel and bronze, I just put a drop of oil on them once in a while and they are happy. The piston rings are viton O rings, again with some oil.

[vtsteam]

Love the sound, and great to see the motion in the back view of the engine! 

[Kim]

Beautifully done, Chris!  And it runs great! 

So, are you going to do some tests to check the power output? Presumably, the double-acting cylinders should make it just as powerful as a 14-cylinder air-powered engine, right? 

Kim

[RReid]

Congratulations on the completion of another interesting and unique model, Chris. Have you tried joining the con rods in the happy dance yet?

[crueby]

Thanks guys!

Kim, you are right that 7 double-acting cylinders should be about the same as 14 single acting ones, should have lots of power. I am NOT going to try and grab the prop as it goes round!  Not sure how I would measure the actual power output, other than measuring how far it can fling a shop elf!  Hmmm, sounds like a Monty Python bit, the lost scene after the Airspeed Velocity Of An Unladen Swallow routine...   

Ron, if I DID try and do the Radial-Engine-Hula-Dance, rest assured that I would NOT post a video!     

About time to wander back to the shop and run the engine some more!   

[EricB]

Amazing!

[Sanjay F]

Amazing as always! Sounds terrific, looks terrific and the motion is .......terrific! What a truly astonishing build; I can't believe you built it in such a short amount of time .......and already onto the next one 

[Krypto]

Unique and awesome model!

[samc88]

Really nice Chris, super quick too! What's next on the list?

[ShopShoe]

Kudos

Mesmerizing to watch.

I enjoy all your projects and I really find your writeups both entertaining and educational.

Thank You for posting.

ShopShoe

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P.S.: Random Extraneous content follows:

The upcoming brewery pump and talk of meeting food dispensing standards starts my brain diverging: Another "Short" project could be a tabletop "visible" gas pump for serving beer. Not sure what the glass tank would be made from, but there's probably something out there...

RE: Demonstrating power from the 7-cylinder might possibly be done with a "wind turbine" facing the propeller and driving a device to show results that vary with the speed of the engine. Electrically a small generator connected to a meter or a series of lights. By fluid a turbine-powered pump could feed a manometer tube or a small fountain.

SS