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Small Scale Engine modelling thread..

Posted: Sun Aug 02, 2009 6:44 am
by inonickname
Does anyone else here enjoy building/running small scale models, such as engines and the like?

It's something I've always had an interest in, but with basic tooling I never got much done. Now I have my lathe (I do have a bit of past machining experience..) I decided to build a (very) small radial. I do have access to a mill, but I wanted to do it entirely with tooling I have at home. For this reason the engine will be made from hexstock. It was originally going to be a 6 cylinder, but for simplicity and time constraints it was changed to a 3 cylinder.

The are no plans, but I'm building it in a certain order that means there will be no sloppy fits or inaccuracy. It uses a rotary valve that opens (in and ex.) slightly before TDC/BDC then closes slightly after. For multiple cylinders, this makes it much simpler and has the potential for more power. Also does away with mushroomed pins. Plus, there's little chance of dieseling with flammable oils or any mineral turpentine in the motor..

I'll post some pictures after dinner. I have started turning out the crankcase and drilled holes to mount the cylinders..

So, anyone else interested in small models/engines.. Planes, jets, steam engines? Boats..

Posted: Sun Aug 02, 2009 7:04 am
by inonickname
Photos..

The cylinder holes are drilled 2mm back (first one is at 10mm, second 12, then 14mm) to account for space on the pin.

Tomorrow it gets cut off the rod and bored out.. I should have drills big enough..but may finish it off with a boring bar to make it nice and smooth.

I'm thinking of knurling the ends of the cylinders and pressing them in, but I may just spread the epoxy goodness.

After the case is finished, I do a crank, backplate, connecting rod(s), pistons, cut cylinders to length, make cylinder heads, finish rotary valve, set up tubes (got to bend a lot of aluminum tube..) make a carby (ball valve, except sealless..shaped like a carby)..Then lap all the parts together and polish.

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Posted: Sun Aug 02, 2009 5:33 pm
by psycix
Hmm when nobody else responds, I'll just say that I think this is an awesome project!
You have just added another thing to my "things I ever want to build" list. :)
Keep the updates coming and good luck with the construction! :D