Author Topic: 15 HP Witte hit-and-miss  (Read 5689 times)

Offline Craig DeShong

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15 HP Witte hit-and-miss
« on: March 26, 2020, 03:00:59 PM »
This build will be a 1/5th size model of Joe Fiddís 15 HP Witte IC engine manufactured in Kansas City, Missouri in 1911.  You can see this engine in the Willock building at the Rough and Tumble Engineersí Historical Association in Kinzer Pennsylvania.  Joe told me this engine powered a water pump for a Rhode Island Estate during it's working career.

Below is a youtube video of it that someone took several years ago.

The engine is a typical ďhit and missĒ engine; the governor controlling the speed of the engine by denying the engine power strokes.  The method of this control however I find somewhat bizarre.  The engine has an atmospheric operated intake valve and an exhaust valve that operates off a cam on the side shaft.  The exhaust valve is lifted during every exhaust cycle regardless of whether the engine fires of not.

Engine speed is controlled by allowing or denying fuel to be brought in with the air during the intake stroke and this is accomplished via the operation of a third valve, up-stream from the atmospheric controlled intake valve in the air intake.  The operation of this third valve is controlled by the fly-weight governor, located on the side shaft.

The full size engine is water cooled,  has a magneto driven by a friction wheel that rubs on the flywheel, and has a compression release to assist starting; none of these will be reproduced on the model.  The full size does have a fuel pump which will be modeled.

Ever since George Britnell introduced me to cutting helical gears Iíve been making my own helical gears.  George seems to knock these off with barely a thought and he produces beautiful gears.  Mine arenít nearly as pretty and I will attest that there is a lot of thought involved, but I seem to produce serviceable gears.  I thought Iíd get the fabrication of the helical gears behind me early in the design because the pitch  diameters of the gears determine so many of the other measurements on the engine.  There is no need to spend days with the design of a model, only to discover you canít make or purchase the gears you plan on using; knowing that substituting different gears will result in changing so many measurements in the design of the model.

I decided to cut these gears from brass, thinking the fabrication of brass gears might be easier than steel.  I also have a growing supply of gear cutters and with careful planning I was hoping to use some of the ones I had without having to purchase even more.  To that end I settled on a diametral pitch of 18, with the gears having eight and sixteen teeth.

These were fairly large gears to cut with a whole depth of over 1/10th inch using Chuck Fellows handy-dandy helical gear cutting fixture.  I made several passes around each gear, increasing the depth of cut at around .020 inches per pass.  The process was slow but the result was serviceable gears; though a little filing was require to have them mesh cleanly.  Though they are a bit noisy they should work well.   

In the first picture Iím forming a gear blank.

Once the blank was formed it was time to cut the teeth.  In the second picture Iíve just finished forming the eight gear teeth on the crankshaft gear.

With the gear teeth formed, the third picture shows me reaming the gear to the crankshaft diameter size after I had first drilled out the center and bored it to near size.

In the fourth picture Iím parting the completed gear off its arbor.

Forming the side-shaft cam gear followed pretty-much the same process.  The fifth picture shows a photo I took while cutting the gear teeth.

With the gears complete I mounted them in a test fixture to make sure they meshed smoothly and the designed distance between the crankshaft and side-shaft were correct.  With that verified I moved on to complete the design of the engine.

The final attachment is an image of the complete design from my Alibre design tool.
« Last Edit: March 27, 2020, 01:43:51 AM by Craig DeShong »
Craig

Offline awake

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Re: 15 HP Witte hit-and-miss
« Reply #1 on: March 26, 2020, 03:07:59 PM »
Great new project! I look forward to seeing it take shape!

I'd love to know more about the fixture and procedure you are using to cut helical gears. Any chance you have links to the relevant thread(s) handy?

Sent from my Lenovo TB-8504F using Tapatalk
Andy

Offline Craig DeShong

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Re: 15 HP Witte hit-and-miss
« Reply #2 on: March 26, 2020, 03:46:42 PM »
Hi Andy.  George Britnell introduced me to a 'fixture' developed by Chuck Fellows that lets you cut helical gears.  If you peruse down through this thread

http://www.modelenginemaker.com/index.php/topic,7769.0.html

you will see several links that should answer your question.
Craig

Offline awake

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Re: 15 HP Witte hit-and-miss
« Reply #3 on: March 26, 2020, 03:50:59 PM »
Excellent - many thanks!
Andy

Offline Craig DeShong

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Re: 15 HP Witte hit-and-miss
« Reply #4 on: March 29, 2020, 04:47:50 PM »
Thanks for stopping by to see the progress of this build.

Several days of activity in the shop has produced the base for the engine.  I'd been saving this piece of aluminum for building the Regal model (a design thread I authored last year) but the Regal has been pushed back again in lieu of building this Witte model so I'm using what I have as opposed to buying more.

Even after carving on it a while you can see from the photo that itís still a rather sizable piece.  This is going to build a fair sized model and I was tempted to increase the scale ratio, resulting in a smaller model but when I got into the design, some of the governor parts were getting pretty small and designing them smaller yet wasnít going to help me see what I would be doing come build time so I decided after all to stick with the 1/5th scale size.

Iíll be moving on to the upper frame next.
Craig

Offline Dave Otto

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Re: 15 HP Witte hit-and-miss
« Reply #5 on: March 29, 2020, 06:10:58 PM »
Hi Craig

Cool that you are off onto another build, looking forward to following along with this one too.
I have had the attached picture for years, can't even remember where I got it; thought that you might enjoy it.

Dave

Offline kvom

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Re: 15 HP Witte hit-and-miss
« Reply #6 on: March 29, 2020, 08:46:28 PM »
Quote
Joe told me this engine powered a water pump for a Rhode Island Estate

They probably had a lot of fountains.   :shrug:

Offline Craig DeShong

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Re: 15 HP Witte hit-and-miss
« Reply #7 on: March 31, 2020, 02:18:01 AM »
Dave.  Thanks for the photo.  A few commentsÖ The water pump, igniter, and most other items that might need serviced are on the side of the engine that faces the wall.  That might make servicing a chore  :'(
In addition, the compression release is located on the side shaft so to release it once the engine had started the operator would need to reach THROUGH the belt at the head of the engine.  :hellno:  OCEA would have gasped at this setup!!!  :ROFL:

Also- how would you have liked to operate that lathe with that engine banging away right beside you?  :hellno:

Kirk: That engine could have moved a lot of water.  I too was wondering just why the estate needed a pump engine so large?  :shrug:
Craig

Offline kvom

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Re: 15 HP Witte hit-and-miss
« Reply #8 on: March 31, 2020, 12:10:01 PM »
Lathe is on a line shaft, but the engine in the pic isn't powering it.

Offline Johnmcc69

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Re: 15 HP Witte hit-and-miss
« Reply #9 on: March 31, 2020, 02:17:16 PM »
That's a very nice engine & should make for a real nice model, especially if made to "tick over" slowly.

 Looking forward to following along Craig, keep up the good work!

 John

Offline Dave Otto

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Re: 15 HP Witte hit-and-miss
« Reply #10 on: March 31, 2020, 04:21:30 PM »
Lathe is on a line shaft, but the engine in the pic isn't powering it.

The belt appears to be there but hanging loosely from something near the window; but could be attached to the wood pulley on the engine if needed. My thinking anyway.

Dave

Offline kvom

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Re: 15 HP Witte hit-and-miss
« Reply #11 on: March 31, 2020, 06:40:04 PM »
By Georgie, I think he's got it!  :ThumbsUp:

Offline Craig DeShong

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Re: 15 HP Witte hit-and-miss
« Reply #12 on: April 02, 2020, 09:48:06 PM »
Kirk, John, and Dave; thanks for your interest and comments.  Thanks also for those just stopping by to see the goings-on.

The last few days were spent in carving a block of aluminum so it sort-of looks like the carriage for this Witte engine Iím building.  Iím back to making mountains of swarf.

Here is a photo of one of my more interesting setups.  I might have had the vertical distance on my mill to do this with the down-feed on the quill, but that would have entailed removing the vice and setting up angle blocks to hold the work piece.  This seemed easier and as Iíve said before; donít miss an opportunity to play with ALL your toys. :Lol:

Iím using my right-angle drive, with a boring head attached and using the power X-travel to feed the work piece into the boring head.  This worked better than I thought it might.  Nothing seemed to be complaining so I incrementally went to the full depth I needed and got a good smooth finish.     


Here are a few photos of the engine carriage or engine frame.  This sits atop the base I made up thread.





Now Iíve moved on to the cylinder.  Iím starting with this humongous block of cast iron.  Iím going to remove at least 80 percent of this material before I get done.  Also, Iíve decided to make the model water cooled as the full size was so Iíll be forming a water jacket in the cylinder and then pressing in a cylinder liner, even though the cylinder is cast iron. 
The engine up at Kinzers and the one in the photo Dave supplied doesnít show how water was moved through the engine.  Iíve decided to add a water pump to the model, probably operated from an eccentric on the crankshaft.

Craig

Offline crueby

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Re: 15 HP Witte hit-and-miss
« Reply #13 on: April 02, 2020, 10:10:32 PM »
Nice results from the right angle attachment - bet that was a real chip-flinger!

Offline awake

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Re: 15 HP Witte hit-and-miss
« Reply #14 on: April 02, 2020, 10:48:39 PM »
Craig, I love the way you use the BP accessories!
Andy