Moteur Oscillant - Double acting Oscillator Twin

[cfellows]

Thanks, Ray. It always feels like a gamble whether it will work out or not.

I've remade the engine frame out of brass. Changed some of the dimensions a bit, following Tony's suggestion. I made the cylinder ports and frame ports the same size using the bigger diameter of the two. I've drilled all the holes except the main inlet and exhaust ports. I also am holding off on drilling the crankshaft bearing holes, awaiting the arrival of some beefier flanged ball bearing races. In the interim, I'm also working on the drawings and designing the remaining parts.

Chuck

 

[SBWHART]

Stew, what didn't you like about the crank web pinched onto the shafts?

thx...
Chuck

It had a tendency to slip, you really have to get the screws good and tight, and pinch in the webs a bit before you assemble the rods, when you get it gripping it works fine:- but I don't think it looks to good, I think grub screws would be far neater, but thats just me.

Pete, Stew, Bogs, it's not clear how he piston rod attaches to the piston. I would have assumed threads but I can't find any indication of thread size in the original drawings?

Yes thats correct they are screwed on same size as the rod M3 I think, I added a bit of thread lock.

Hope this helps

The engine is comming on great I'm sure it will be a good runner.

Stew

 

[mzetati]

I've remade the engine frame out of brass.

Hi Chuck,

glad You did it!
On my very first engine, the David II wobbler, I had made the column and cylinder in aluminium: as soon as I had a nice finish on both surfaces, I set the pivot and moved them a few times by hand.
Three or four strokes, and they got hard to move.
Learnt the meaning of the word 'galling' the hard way.
I've built one of those MV-DEO some years ago: definitely a nice runner, though I put bronze bearings in place of the ball racers.

Marcello

 

[cfellows]

Got a little more done today. Finished up the crank disks and completed the flywheel. I also located 4 ball bearing races identical to the ones I had just ordered on Ebay. Not sure how I missed them, but now I will have some extras when they arrive in the mail.

Here's some pictures of the assembled engine so far. Still have to do the pistons and rods as well as the manifolds and the reversing valve. Oh yeah, then I get to start on the base...

The bore and stroke on this engine are 7/16" & 7/8" respectively. This makes the overall displacement about 37% greater than the original engine with a bore & stroke of 10mm & 20mm respectively. Guess that means it'll take 37% more steam to run it... hadn't thought of that. ???

Chuck

 

[lazylathe]

Looking great Chuck!!! Thm:

Can't wait to see what type of base you make for this engine!!!

Andrew

 

[doubletop]

As usual that's looking good Chuck, you'll need a 37% bigger boat

(now somebody can put me right that the relationship between engine bore, stroke, boat displacement/length/drag whatever isn't linear)

Great job

Pete

 

[steamer]

Doubletop,

That is a large can of worms...and I don't want to do that in chucks thread....it "depends". ;D

Dave

 

[cfellows]

I had forgotten how finicky these little oscillators are to everything being in alignment. I got the pistons and rods finished, put it all together and found some severely sticky spots in places. So, I've got some checking to do.

One thing I found is that the frame had spread on the crankshaft end when I milled out the center opening.

I'm wondering if there is a way spring it back without breaking it. Since I had bored the crankshaft hole before milling the opening, the holes are now sprung out of aignment, but I don't think that's a problem When I insert the bearings and crankshaft, it turns over freely enough. I wounder if I could get by with just milling the outside surfaces flat?

Chuck

 

[maverick]

Chuck,
Use a gage block stack or adjustable parallel in the slot to guard against over bending, and squeeze the ends together untill
they're straight. When you screw up as many parts as I have, you have to get good at fixing them. Great looking engine.

Regards,
Mike

 

[mzetati]

Chuck,

I'd put it lenghtwise into a vice (only to have it aligned again) when fitting to the base: the four screws should keep it aligned an no one will ever know.
I'd scribe a note on the underside of the base, to remind me to put it into a vise again, if servicing will be required.

Marcello

 

[cfellows]

Chuck,
Use a gage block stack or adjustable parallel in the slot to guard against over bending, and squeeze the ends together untill
they're straight. When you screw up as many parts as I have, you have to get good at fixing them. Great looking engine.

Regards,
Mike

Thanks, Mike, that's what I did. I hadn't used gage blocks before an that does help. I used stacked feeler gauge blades and kept removing one, then bending, until I got it where it needed to be. Now everything goes together nicely. Seems that cured all my alignment woes.

Chuck,

I'd put it lenghtwise into a vice (only to have it aligned again) when fitting to the base: the four screws should keep it aligned an no one will ever know.
I'd scribe a note on the underside of the base, to remind me to put it into a vise again, if servicing will be required.

Marcello

Good idea, Marcello. I would have probably used your method had I not already gone with Mike's advice.

Chuck

 

[cfellows]

Well, still a ways off from completion, but it runs! And it runs good, quiet, and solid.

For all you steam buffs out there, I finally get it! There is a whole new level of satisfaction from building an engine that is designed to power something, to actually do some work. I think I'm going to have a lot of fun with this project. Can't wait to get the engine finished and start planning the boiler.

Oh, yeah, and I guess I ought to figure out what I'm going to power with it. Still leaning toward some kid of land vehicle.

Chuck

 

[ironman]

Chuck, you whipped that out pretty quick. Looks good. Can we see a video with sound soon?

Looks like you changed the Crank shape some and the lower cylinder cover doesn't have the strap bolted on. Are those some of your mods?

Good job. Thm: Thm: What type of land vehicle have you thought about?

ironman (Ray)

 

[kustomkb]

That's a really cool looking engine Chuck.

Nice work!

 

[cfellows]

Chuck, you whipped that out pretty quick. Looks good. Can we see a video with sound soon?

Looks like you changed the Crank shape some and the lower cylinder cover doesn't have the strap bolted on. Are those some of your mods?

Good job. Thm: Thm: What type of land vehicle have you thought about?

ironman (Ray)

Thanks, Ray. I'll put together a video once I get the engine mounted on a base. Right now I have to hold in my hand to run it, while also holding the air tube on the fitting so it doesn't blow off!

The crank's shape is a little different... mine was easier for me to machine than the drawing. Instead of packing on the bottom of the cylinder, tightened by two screws and a strap, I machined a two part bottom with an o-ring in the middle. For a land vehicle, I'd really like to build a tank or a caterpillar, but I'm stumped on how to make a suitable set of metal tracks. Maybe something like a 4 or 6 wheeled crawler. It'll be some kind of off-road vehicle, slow but powerful.

That's a really cool looking engine Chuck.

Nice work!

Thanks, KB.

 

[Maryak]

I'm stumped on how to make a suitable set of metal tracks.

Chuck,

Very Nice engine. :bow:

How about bike chains side by side or a drive chain with more than one sprocket.................just a thought, (I know..........it's a dangerous pastime).

Best Regards
Bob

 

[SBWHART]

Good job Chuck it really does look a powerful engine .

but I'm stumped on how to make a suitable set of metal tracks. Maybe something like a 4 or 6 wheeled crawler.

You could use a toothed timing/drive belt for a track you can pick them up quite easily along with the sprockets, just google timing belt.

Stew

 

[bezalel2000]

Hi chuck

Nice machine Thm:

I'd really like to build a tank or a caterpillar, but I'm stumped on how to make a suitable set of metal tracks.

Thanks, KB.

lament the good old days! when model track links came on the tops of beer cans. :big:

Now you throw them away with the can. :

Bez

 

[steamer]

Hey Chuck

Nice engine! you'll love the sound it makes when it gets down to work and puts forth a nice "bark" out the exhaust....I always love that sound.

:bow:

Dave

 

[Blogwitch]

Chuck,

I can give you a rough idea of the size of boiler required. I ran mine on a 3.5" diameter x 4.5" (approx) water filled area vertical boiler heated by gas from just the bottom end, thru about eight vertical tubes that kept the engine running continuously, engine regulated at 20psi with the boiler blowing off at 45psi continuously. One about the same size would be perfect for yours. As I have said before, they are not designed to be a fast running engine, but one with oodles of low end torque, so steam consumption is rather meagre compared to the modern day commercial 'square' engines that run a lot faster. A well regulated boiler of that sort of size should keep you steaming for around 30 to 45 minutes, maybe even an hour. I can take some piccies of the boiler if you need an idea of what to aim for, it is still sitting in the back of my shop.

I would recommend doing the horizontal engine layout though (even if you have it standing upright), with the double output shaft (much better for a land based vehicle). The way yours is built is to drive a single prop shaft in a boat. The flywheel is not necessary, and a 3 to 1 or 4 to 1 reduction would be ideal (mine is 3 to 1). I reckon even my smaller one at 20psi would be able to haul around 20 to 30 lbs in weight quite easily.

I hope this helps a little


John