Unknown Model Engine Casting

[Jo]

Along with a very nice birthday set of castings  I was given this little sweetie today, the problem is we don't know anything about it other than it was cast in the USA

Does anyone know anything about it? And do you know if there are any drawings available for it?

Jo 

[b.lindsey]

Can't help with the source Jo, but from the looks of it it's quite a small aero type engine. Whoever did it is likely long since out of business though.

Bill

[Jasonb]

Well if it came from your usual supplier and he did not know what it was there is little hope for the restof us being able to name it

J

PS put it somewhere safe so it does not end up with that Kittie casting you can't find

[Jasonb]

Is it an Ohlsson or Jr. Brown Jr. (recast)?

[Jo]

This is a Jnr Brown Jnr crank case in comparison with my little one.

Jo

[b.lindsey]

Jo, the folks at www.littlelocos.com offer a couple of barstoc aeor engine plans. In there research in developing these engines maybe they have run across this particular design, especially if it was produced in this side of the pond. Sorry I can't add more.

Bill

[Jo]

Thanks Bill, I will check with them.

Back at the Guildford show one of the other Guildford members showed us a small engine about twice the size of this one and that ran . And I know that someone in Eastern Europe makes engines about this size. I can't remember if he publicises the drawings but I do remember that he has been known to make hundreds of cylinders/pistons for a single engine trying to get the fit right 

I reckon I could just about put a 3.2mm diameter bush down the nose which would allow for a crank diameter of say 2.4mm. The crank could have about 6.35mm diameter web, bring the pin in about 1.2mm would give a 4mm stroke The fins will have to screw into the crankcase which means the bore will have to be under 3mm diameter.

Not a very big cc... I think the killer will be the ignition or maybe it could be a diesel

Jo

[Allen Smithee]

You'd be looking at diesel in that size anyway - that or compressed air/CO2/Steam. But you could always do the cylinder "cox style" as a one-piece steel cylinder with integral fins and ports that screws into the crankcase casting - this might allow the bore to be bigger as you don't need to allow for the thickness of the liner AND the fins thread. Alternatively you could do the same but with separate alloy fins that screw onto the outsode of the cylinder rather than the inside of the crankcase. Or perhaps use the fins to hold the cylinder (which is just "spiggotted" into the crankcase) and have the fins tied to the block with long screws or studs, again making more of the dia available for the bore.

I have a couple of cox TD020s (0.3cc) if you'd like to borrow one to see how they did the whole screw-in-steel-cylinder-with-integral-fins thing. You might also want to copy their ball-ended con-rod swaged into the piston concept as a simpler approach than a gudgeon pin and little-end (which could bit a tad fiddly in these sizes).

A diesel in that size would want to be long-stroke anyway, so if the stroke is 4mm then 3mm isn't too far out as a bore.

£0.07 supplied,

AS

[Allen Smithee]

Another thought - piston fit will be difficult enough in that size, but getting a good contra-piston fit could be a serious pain in the Donald Trumps. You could possibly look at using the fluorocarbon membrane approach developed by DDD to get around this.

AS

[Vixen]

Jo
With an engine that small, perhaps ignition of any kind is out of the question. It could more easily be made to run on CO2. Just like this little jewel of an engine

[Jo]

  I like that Mike that is a serious possibility.

Are there any drawings? 

Jo

P.S. I know of a second of these castings 

[b.lindsey]

Actually the Cox company made them as small as .010.  Remember too that their glow plugs screwed into the top of the cylinder and thus became a combination cylinder head AND glow plug.

Bill

[Vixen]

Jo

Sorry no drawings, you can borrow it to reverse engineer it and make your own.
I will pop it in the post if you PM your postal address

Cheers

Mike

[Allen Smithee]

Actually the Cox company made them as small as .010. 

I have a couple of TD010s as well (one unrun), but I ain't lending those out to *anyone*(not even Jo!)

AS

[Jo]

Thanks Mike, but it looks like I have found a set of drawings I can modify http://www.floridaame.org/Plans/Mini_V1/Mini_V1.htm

  Another one to add to the build list with the others from yesterday

Jo

[tangler]

Back at the Guildford show one of the other Guildford members showed us a small engine about twice the size of this one and that ran.

That was the Nano http://modelenginenews.org/~modeng74/nano/index.html

Rod

[Vixen]

Jo

Those drawings look like an excellent starting point. But how are YOU going to cope, the dimensions are in INCHES

Douh!!!!

[Jo]

I have a magic CAD program you type in inches and it corrects it to real numbers automatically 

Jo

[Jasonb]

But why not just draw it in metric in the first place and use nominal metric stock like a 3mm bearing and 2.5mm crankshaft rather than a 3.175 bearing and 2.38125mm shaft

J

PS there was a 4 page article on building the V1 in MEB #17

[kvom]

Don't go getting practical Jason!   

[b.lindsey]

Yeah...where's the fun in using stock sizes 

Bill

[Art K]

Its a stock size somewhere.
Art