E-gad, he’s making another one of those crazy pop-up things

[crueby]

quite a mechanism, great to see the details like that!  I wonder how many versions wound up in their scrap bin as they were developing it.

[Craig DeShong]

Kim, Art, Chris; thanks for your comments.  Thanks to those just stopping by to see the latest too.
Chris: I’d say, quite a few.  I find it hard to wrap my head around this stuff sometimes.  It’s kind of like designing locomotive valve gear; all the different types: Southern, Baker, Joy… Better minds than mine visualized this stuff before we had computer modeling.

This morning I was looking through the drawings of the parts I’ve yet to make and I realized that I excluded a very important part from my previous up-thread discussion of the parts remaining before I can test the engine.  I’ll need to make a part I call the “exhaust valve”.  This is a one-way ball valve and it resides external to the slide valve on the exhaust side and prevents the engine from drawing air back through the exhaust port.

This is a very necessary part of the full size engine; on the model… hard to tell.  Stepping into the middle of the combustion cycle; the piston has been driven up toward the top of the cylinder by combustion, atmospheric pressure has arrested its upward motion, and it is now being driven back down the cylinder by atmospheric pressure working against the partial vacuum in the cylinder.  This action spins up the flywheel where kinetic energy can be stored and used by the engine load.  At the same time, the slide valve is cycling from the closed position and is starting to open the exhaust port.  Were this external “one way exhaust valve” not assembled on the exhaust pipe, the engine would just draw air back through the open exhaust port and into the cylinder, robbing the engine of the power it reclaims through the atmospheric pressure driving the piston downward.  The full size engine cycles over several seconds, and it’s easy to see where this external valve is needed.

The model however cycles much faster.  The piston and rack moves so quickly that it hard to observer exactly how high the rack travels.  With the rapid cycle of the model, it is possible that all the energy has been reclaimed before the slide valve opens the exhaust port.  It’s hard to tell. 

Making and adding this part to the model isn’t going to hurt anything if it isn’t needed and certainly will perform a useful function if it is required.  Also, since this is a scale model, it ought to have a representation of all the parts on the full size.

On the full size this part is a casting; so once again I’m attempting to machine something that at least remotely resembles the part on the full size.
 
This was an interesting part to make.  It is a rectangular body with two cylindrical projections at each end with a flange at the end of each.  Below I’m cutting one of the cylindrical projections.


Now I’ve turned the part around in the lathe and am forming the projection on the other end.



After a little standard machining I show the finished part below; sitting atop its drawing so you can see the internal passage ways.

[Craig DeShong]

Thanks for stopping by. 

After getting the ignition circuit and the acetylene piped in I thought I’d give the engine a trial run.  It wasn’t complete yet (still isn’t), but I certainly could work out any “kinks” before starting in on the governor.
 
These things certainly are full of surprises and each one I build seems to have its own personality.  If you remember, (I certainly do) when I first tried to run my 3rd Gen. engine I built last fall I had too much fuel piped in and on the first ignition, the piston was driven to the top of the stroke violently against the spring restraint(which was too weak) and the rack was broken.  I didn’t want to repeat that error again, so I was very conservative at first with the fuel I allowed the engine to have.  Therefore, I cranked it and cranked it and cranked it, slowly opening the fuel regulator until it finally, very weakly fired; a little more fuel and I was in business.

As I think I noted up-thread, the engine did need a few adjustments before I had it running dependably.  In the following video it’s running about as well as it will run in an un-governed state.  Its running “wide open” without a governor to regulate the speed, but it certainly will get up to speed in a hurry so I’m thinking that an appropriately designed governor should regulate its speed nicely.

<a href="https://www.youtube.com/watch?v=EdP0JoUbatQ" target="_blank">http://www.youtube.com/watch?v=EdP0JoUbatQ</a>

BTW, in-case you wonder; yes, the flywheel keys need seated and adjusted.  I’ll probably have the engine apart and together a few more times till it settles in, so I’ll wait to seat the keys till I’m ready to call it “done”.  Besides, I still need to make the drive pulley for the main shaft.

[kvom]

Egads, it's popping up.   

[Roger B]

Excellent     

[MJM460]

Beautiful to see another successful runner.  The governor is surely the home stretch now.

It’s a real tribute to the skill you put into building this unusual engine.

MJM460

[Dave Otto]

Congratulations on a runner, nicely done!

Dave

[Jo]

  Well Done

Jo

[Kim]

Congratulations on getting it to run so quickly, Craig! The video is fascinating to watch.
Kim

[Jasonb]

Another good running engine, should now be able to make a start on that Benz soon

[Vixen]

The crazy pop-up thing lives. 

Well done

Mike

[fumopuc]

Congratulations, very nice and a pleasure to watch.

[Chipmaster]

Marvellous 
Andy

[Art K]

Craig,
It runs great, by golly.
Art

[Admiral_dk]

I'm impressed how smooth this one runs - even without the governor