Salutations from SoCal

[betasniper]

Hi. Uhm, my background is in machining as I had a mold/tool-maker for a father so I got into that from an early age. I had always taken apart toys to try to see how they work; most of the time failing to put them back together :wall:. I started learning machining at the local community college whilst in high-school and did several model engines as projects for the class; however they never worked as intended. The types of engines are as follows: A Gamma Stirling engine, A compressed air V4 engine, And A 5 cylinder radial wobbler engine. I don't know what exactly went wrong with those projects but fed up with them, I decided to design my own as I was taking a GD&T class at that time. Squared off one is the prototype made with manual machines and a drill press while the other is the proper CNC made one that I made a few months later and both work great, especially considering that was the first attempt at something like that and it has no exhaust vent. Around 2014, I became the Lab Tech for that particular class and this engine --the CNC one-- became the standard project for the Class and now every student that finishes the engine actually has a functional engine to play with instead of a pretty paper weight.

Interestingly, The engine always turns forwards when supplied with compressed air no mater the crank angle the engine was at. Very Mysterious. Any Ideas why?

 

[Blogwitch]

Nice one Beta, or should I say two.

Everyone has to start somewhere, as they say about little acorns.

You are definitely on the right track by joining in here, plenty of experience in problem solving and lots of experience of building, from little wobblers to world class engines.

As I always say, please complete your profile, just so that we know what part of the world you come from.

Just enjoy yourself

John

 

[Herbiev]

And a big welcome from down under

 

[Cogsy]

And another welcome from down here.

 

[betasniper]

Thank you all for the big welcome.

I do wonder is there a learning resource here that lists all the types of model engines and their difficulties? I see some types that I don't know what they are called or what the parts are called like in the icon at the top where the engine attached to the propeller seems to have a chuck key stuck in it

Also, what are the common sized parts used like for spark or glow plugs? Seems to me that it is hard to find all this info when I don't know what it is I'm to look for. Perhaps there is a thread like this somewhere already?

 

[Cogsy]

I see some types that I don't know what they are called or what the parts are called like in the icon at the top where the engine attached to the propeller seems to have a chuck key stuck in it
?

That's a model 'diesel' (compression fired) aero engine and the 'chuck key' on top is usually called a 'tommy bar' and is used to adjust the contra piston which changes the compression ratio. They're fairly complex things to make as far as I know.

Also, what are the common sized parts used like for spark or glow plugs? Seems to me that it is hard to find all this info when I don't know what it is I'm to look for. Perhaps there is a thread like this somewhere already?

For glow plugs you have to stick to what the manufacturers make - I'm not familiar with the sizes as I don't do glow, but they're published and easily found. For spark plugs, you can buy commercial miniatures in certain sizes or you can just make your own to whatever size you need/want, which is what I do. So far all mine have a M6x1.0mm thread size but making smaller or larger isn't difficult.

As far as sizes for bore and stroke etc. they vary from the incredibly tiny (like I think 3/8 of an inch for internal combustion) up to 1 inch (or more). Generally, it is more difficult to make very small engines than larger ones as your tolerances need to be very tight.

If you're looking at internal combustion it's common for lots of builders to start with the Webster fours stroke, although if you're new to machining it's suggested to start with a simple wobbler/oscillator and work up from there.

 

[betasniper]

Thank you Cogsy

I really want to try a combustion engine, but I think as a first engine it needs to be as idiot proof as possible.

Here are the earlier models we had to make, neither ran so I had donated them to the display case. I think I now know the problem with the 5 cyl. the center hub was supposed to be attached to one of the piston rods. We didn't know and we left it loose which meant when spun, it flopped the pistons around or locked up. Lesson learned way too late.