Geared horizontal twin engine

[Brian Rupnow]

I believe this is the last part to be machined for this engine. Since the main air valve is a single feed and is then split to run out to each cylinder, there is no way to test and set up the engines individually. This single air feed adapter lets me take the main valve and air manifold off the engine, and then it attaches to one steam chest to set up only that engine. Then it is removed and attached to the other engine for setting it up individually. After both engines have been set up to run individually, then this part is removed and the normal valve and air manifold are reattached to the engine.

[Brian Rupnow]

Santa came to our house last night, same as he always does. I must have been a good boy this year because I ended up with new socks, t-shirts, sweaters, and a new pair of shoes. I generally buy "odorless" varsol to wash down oily, greasy parts with. After considerable time "running in" my newest engine, and constantly supplying it with squirt can oil, it was filthy with a mixture of oil and powdered aluminum and brass. I was out of odorless varsol this morning, so tried to sneak some lawnmower gas into my workshop and wash down the engine. I immediately got yelled at by good wife for "Stinking up the house", so had to abandon that idea. Much later in the day, I finished cleaning up the engine and machined a new cam-shaft with keyways for the flywheels and a flat for the set-screws in the central gear. Tomorrow, if things don't come amiss, I am going to ty and run this engine.  After I get it running to my satisfaction, I will remove the flywheels and the steam-chest covers and paint them.

[Art K]

Brian,
Sorry to hear that you made the good wife unhappy, that's bad. I guess I have one advantage over you, detached garage. Anything I do in the garage stays there. Hope you have good results running it tomorrow. Bye the way Merry Christmas!
Art

[Brian Rupnow]

Thought I would have a runner today, but it didn't happen. The current valve control rod set-up is not strong enough, and due to the stresses involved the 1/8" diameter steel rod bent and then broke just beside the blue nut in the top picture. Tomorrow I will canibalize all of the existing parts and fabricate a new brass piece as seen at the bottom of the picture, which will have much more resistance to bending or breaking.  Also, I am going to have to add a piston ring to the pistons. I can re-use the existing pistons and simply turn a ring groove in them.

[crueby]

huh - never had any trouble with valve rods that thick (usually use thinner). Possible that the slide valve hit the end of the steam chest?

[Brian Rupnow]

Today I revisited the valve control rods. These rods have a high bending moment applied to them if there is any binding between the eccentric strap area and the eccentric itself. As the eccentric revolves, this sets up a reversing moment in the rod, and if the rod is smaller than 1/8" in the threaded area, it soon fails in a stress type failure. I'm not concerned about weight, so have spent part of today making newer heavier links.

[Brian Rupnow]

This time around, I fitted the eccentric straps to the eccentrics off the engine. The broken 1/8" connection rod was totally my bad. Sometimes I try to cut corners, and end up in the $hit. The holes in the current and the earlier version of the eccentric straps was reamed to 0.750". The eccentrics were a couple of thou oversize. I thought I could work that down while running the engine in and gradually tightening the connecting bolts as things loosened up. This resulted in failure of the 1/8" rod. I have a vertical spindle sander here that takes different diameters of rolls. I used it to open the 0.750" bores on these new "eccentric straps" to 0.752+/- and then worked the final bit down with 600 grit lapping paste. Like the saying goes, "The hurrier I go, the behinder I get".----Brian

[derekwarner]

With the strengthening of the valve control 'rods' to a larger section body plates at the eccentric end, not transfer whatever torsional moment along to the next weakest joint?

The same  1/8" rod section [of greatly reduced length] at the clevis end will be far stiffer and less prone to the twisting failure, so the next weakest link could be the clevis /clevis pin?

If this is the case, excessive wear may take place between the clevis yoke plates and the pin?....as the contact surface bearing area of this pin is many x 10's of  fold lower than the eccectric contact bearing area

Derek

[Brian Rupnow]

After much finessing today, I think I'm about half way home. I didn't o-ring the pistons because all my stores are closed due to Covid and I didn't have the size o-ring I need in stock. I do have one engine working. Don't have it all hooked up yet, but when I manually operate the slide valve, the piston takes off like a wild thing in either direction. The other engine isn't doing it's thing quite yet, but is very close. it needs some more attention to the slide valve and steam chest I think. I've had enough fun for one day .

[Brian Rupnow]

So here we have it kiddies. After a sometimes frantic 5 weeks from concept to completion, we have a running twin cylinder engine with the flywheels running off the camshaft. I still have timing events to adjust, and some painting to do, but this "maiden run" has been successful. I will sell a complete plan set for this engine for $25 Canadian funds, and I will find a commercial source for the gears if you don't have your own gear cutters.---Brian
<a href="https://www.youtube.com/watch?v=GWenKfKOUQY" target="_blank">http://www.youtube.com/watch?v=GWenKfKOUQY</a>

[Brian Rupnow]

This is the final "wrap up" of my geared horizontal engine. Painting and polishing has been completed, and there really is nothing further to do on this project. It has kept me entertained for a month, and shows that yes, the flywheels can be mounted on a geared shaft which is driven by a gear mounted on the crankshaft. I have seen this discussed many times, but the answers were always a bit ambiguous. This answers the question. Thank you for following my build thread.---Brian
<a href="https://www.youtube.com/watch?v=0G_JM3hRCR8" target="_blank">http://www.youtube.com/watch?v=0G_JM3hRCR8</a>

[crueby]

Running great!      

[Art K]

Brian,
Its great to see that you have an engine that runs so well, and looks great to boot.
Art

[Pete49]

Once again a great engine design. To go from start to running in six pages is a feat in itself. How does on go about purchasing the plans down here in Australia?

[Brian Rupnow]

Pete49--Go to Paypal and put the equivalent of $25 Canadian into Paypal under brupnow@rogers.com  They immediately notify me that the money is there, and I email you a .zip file with all of the drawings in it. Be sure and specify which engine you want plans for. Then you can print them out and build it.---Brian