New Compressed Air Hit n Miss Engine

[CallMeAl]

Very imaginative work!  I am looking forward the the little gem of an engine is is destined to be.

[saw]

Nice work. 

[John Hill]

A very interesting project Chuck and I am looking forward to see how it runs!

[raynerd]

Hi chuck, nice work. What setup do you use for cutting the gears and did you use purchased cutters or homemade? I'm always interested in gear cutting!!

Excellent stuff Chuck, keep it up!
 

[cfellows]

Hi chuck, nice work. What setup do you use for cutting the gears and did you use purchased cutters or homemade? I'm always interested in gear cutting!!

Excellent stuff Chuck, keep it up!
 

I used a spin index with a 5/8" 5C collet.  The gear blanks were mounted on a spindle I made from 5/8" CRS.  The spin indexer was modified several years ago by cutting the flanges off the base so it would clamp into my milling vice.  The cutters were commercial, 24 pitch involute gear cutters.

Thx...
Chuck

[cfellows]

Managed to get a few more things done.  The governor is patterned after the one Phil Duclos used on his Victorian engine.  I made the 5/8" brass balls using an over-the-top ball turner that I had made several years ago.  Before I could use it however, I had to adapt it to my QCTP.  I used the boring bar holder and inserted a 3/4" brass bar that I had bored out to 1/2" to accommodate the 1/2" shaft of the ball turner.  The small protrusions on one end of each ball will be turned off and bored to accept the swing arms of the governor.



I also made the piston and the connecting rod.  The latter is made from 3/8" thick x 3/4" wide aluminum.  Finally, I also finished the crank disk but still have to make the crank pin.



And, here's a couple of images with a few of the parts loosely hanging in place





Chuck

[cfellows]

Well, I think I'm within a day or two of having this thing ready for a test run.  It will take a little longer to get the governor bits all hooked up so it runs in hit n miss mode, but I should have all that part finished as well in less than a week, maybe by the weekend sometime.  I'm really pleased with the way everything is turning out.  I think this will be a nice looking and good running engine.





Got to get it finished, I'm already thinking about my next project.

Chuck

[sbwhart]

 

Thats comming together real well Chuck, looking forward to seeing it run.

Stew

[cfellows]

Thanks Stew.

I got the engine running last night and made a number of improvements and tuneups today.  Once I got it all together, there were several embarrassing problems that I had to correct. 

- The connecting rod was too long so the piston was hitting the head before top dead center.  Had to mill a depression in the head and face a 1/16" off the top of the piston. 

- The connecting rod was hitting the side of the cylinder so I had to turn a bevel on the inside of the cylinder and turn the rod down to a smaller diameter.

- The valve travel was insufficient to open the valve, so I had to do some more machining on the cam.  Also had to increase the dwell since the valve wasn't staying open long enough.

Today I corrected all that.  I also added the plumbing to bring the air supply line out the side of the base.  Now all I have left is to complete the governor and valve latching mechanism so it will run in hit n miss mode.
Got a video loading on youtube at the moment.

I will post the video as soon as it finishes uploading.  Here are some pictures.



















Chuck

[cfellows]

And here's the video...

http://www.youtube.com/watch?v=9xECJ4WTrf8

Chuck

[sbwhart]

 

Very Very Nice Chuck sounds like a big engine, 


I,m intersted seeing how you link the hit a miss governor up.

Stew

[Dean W]

Really neat, Chuck.  It has a very satisfying bark to it, too.
I watched through the thread as you built and had an idea of the size, but there's nothing like
seeing a guy's hand reach in there to really get a sense of size.  It's pretty big. 
What a good engine it is!

Dean

[srm_92000]

Hello, I've been following the build with interest. 

Love the valve system etc. and sounds just great

 
Shame it's not a twin or 'V' 4 though


Cant wait to see the governor link working.

 
Steve

[Rob.Wilson]

Hi Chuck


Now thats a very clever bit of engine design work ,, ,, you have the period look right 

Great runner too 


Rob

[cfellows]

First, thanks to everyone for the appreciative comments.  Always enjoy knowing people are watching.

I was drilling and tapping 2-56 holes in the brass governor balls today to hold the screws that the springs will attach to.  Of course, on the second ball, the tap got stock and I broke it off trying to get it out.  Still not sure why it stuck.  Anyway, after a few minutes of muttering and resisting the impulse to throw the part across the shop, I got the torch out to heat up the ball so I could take it off and make another.  After I got it off, I was standing there looking at it when it ocurred to me, why not just rotate the ball 90 degrees and glue it back on?  So, that's what I did.  I put the broken tap hole on the inside where it will probably never show any. 



Now if I can just drill and tap the holes without breaking a second tap... of course, I could always just rotate it 45 degrees and try again!

Chuck

[Bernd]

Keep drilling holes in it and you'll have a "wiffle ball".   

Nice work so far. 

Bernd

[cfellows]

Here's another video, this time in hit n miss mode.  It's hitting every 3rd revolution of the cam which is every 6th revolution of the engine.  Since I posted this video, I've made a couple of changes.  I opened up the inlet passages from 5/32 to 3/16".  I think I have one more place, the hole in the side of the valve which is still 5/32 which I will check later.  Now it's hitting about every 4th revolution.  I'm also going to add an o-ring to the piston and see if that helps.  But for now, it runs pretty good.

http://www.youtube.com/watch?v=hNC36MoBCyw

Chuck

[Brass_Machine]

Chuck...

Very nice. Again, have you given thought to putting all your plans and designs into a book? I know I would buy one.

Watched the videos. Engine sounds great. In hit/miss mode it has a cool rhythm. My wife thought I was listening to a song on low volume 

Eric

[BiggerHammer]

Very nice, one you should be proud of. Excellent on the governor.

[cfellows]

I'm considering this engine completed.  Took me a couple of days less than a month from start to finish.  After the last video, I opened up all the inlet air passages to 3/16" and also added a single o-ring to the piston.  With those mods and a little breaking in, the engine will now coast between 10 - 12 revolutions between power strokes.  Don't think I can do much to improve it now except maybe bore it out a little, but I think it sounds fine as is.  Here's the final video:

http://www.youtube.com/watch?v=oR8q_vDgXD0







Recap:  1" bore x 1.5" stroke, flyball governor (5/8" balls), 7.25" flywheel

Chuck

[CallMeAl]

Great work and wonderful result!  Sounds great and I like how the governor works. Thanks for sharing your work Chuck!

[NickG]

Absolutely brilliant Chuck, it runs so well in hit & miss mode now. I presume as soon as you put any kind of load on the flywheel it'll start hitting?

So cool 

I agree with Eric, if you feel you've got the time a book would be a great idea!

Nick