Author Topic: Another beginner engine - McCabe Runner redo  (Read 5089 times)

Offline black85vette

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Another beginner engine - McCabe Runner redo
« on: February 09, 2013, 03:33:29 AM »
Took the same approach to this engine as I did with Elmer's Standby.   Reduce the materials required, simplify the build, and use minimal tools.   For this one I scaled it up a bit and used the same main material; .75" x 2" aluminum bar.   From that we get the cylinder, main shaft support, flywheel, support for the bell crank, the bell crank, and main crank.   Here are the pieces;


IMG_5908 by black85vette, on Flickr

The cylinder is .5" drilled 1.375" deep.   Piston is .5" long and stroke will be .75".   Behind the cylinder is a .25" hole cross drilled.   This will house the valve.


IMG_5909 by black85vette, on Flickr


From the rear of the cylinder a .125" hole is drilled all the way through to the cylinder.  The air supply will connect here.



IMG_5910 by black85vette, on Flickr


The valve is the main change I made to the original runner design.  The original had a piston valve that had to push against the air pressure to work.   Instead I brought the air supply in the rear and used a hole in the valve to control the air inlet.    I made a flat on the end of the valve that is .5" long and .050" deep.   This is the exhaust port.  On the other end of the valve is a flat that is rotated 90 degrees for the linkage and tapped for a screw to attach the link arm.




IMG_5912 by black85vette, on Flickr


I took a little different approach to the link for the bell crank.   This link has the ends 90 degrees apart and it has to move in two different planes.   In the past I have used a .25" round rod and just drill it with the ends rotated 90 degrees.   I have seen a flat piece used and twisted in the middle to get the holes aligned.   In this case I decided to use some linkage from an RC helicopter rotor.   These ball links are threaded and can pivot over a wide range.   Plus the threaded rod that connects them makes it very easy to adjust the length.



IMG_5913 by black85vette, on Flickr


Here is the bell crank.   I made a brass pivot for it to ride on.   Then drilled / tapped holes at two corners.



IMG_5914 by black85vette, on Flickr



IMG_5915 by black85vette, on Flickr


Flywheel and Piston are the same as the last engine so no need to show them.

There you have it.  I have some drawings in process and will get something posted.

Also thinking about moving my original EZ Engine over to this same material / format.

Offline black85vette

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Re: Another beginner engine - McCabe Runner redo
« Reply #1 on: February 09, 2013, 03:39:34 AM »
A quick video;


Offline ths

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Another beginner engine - McCabe Runner redo
« Reply #2 on: February 09, 2013, 06:51:15 AM »
I like that! It looks as though it's madly shaking hands with itself. I like the changes you've made, it looks a more convincing engine than I recall the original plans showed.

Cheers, Hugh.

Offline zeeprogrammer

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Re: Another beginner engine - McCabe Runner redo
« Reply #3 on: February 09, 2013, 12:12:08 PM »
Nicely done Rick. That should inspire some newbies wanting to make their own engines.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline b.lindsey

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Re: Another beginner engine - McCabe Runner redo
« Reply #4 on: February 09, 2013, 12:54:12 PM »
Very nice Rick!! I agree with Zee, would make a very nice first engine.

Bill

Offline Don1966

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Re: Another beginner engine - McCabe Runner redo
« Reply #5 on: February 09, 2013, 02:51:27 PM »
That's what I call simplified, very nice Rick and a great first engine project.

Don

Offline black85vette

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Re: Another beginner engine - McCabe Runner redo
« Reply #6 on: February 09, 2013, 09:34:03 PM »
Thanks for all the comments!

A couple of things;

1. Does anyone know the name for this type of valve?   I have used it a couple of times and don't know what to call it.   If I get my third engine done there will be 3 engines that are very similar in construction but use 3 very different valve / timing methods.

2. These are just prototypes at this point.   If you have a comment, idea or suggestion to make them even more beginner friendly post your thoughts.   When I am comfortable with each I will do more of a step by step build instructions.

Offline black85vette

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Re: Another beginner engine - McCabe Runner redo
« Reply #7 on: February 12, 2013, 08:11:27 PM »
Here are the basic dimensions for this engine.

Offline Tin Falcon

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Re: Another beginner engine - McCabe Runner redo
« Reply #8 on: February 14, 2013, 12:29:16 AM »
IMHO the McCabe runner is an excellent choice as a beginner engine.  I have built a couple


Pretty simple as is  my first one I used a piece of brass as a valve machined it bet it and stuck it in the valve plate. and made a valve rode from a piece of coat hanger. primitive but effective. I used a piece of square aluminum tube with hat bushings for the main bearing and a sqare piece of aluminum held with super glue to hold it to the base the bottom plate is drilled and tapped for a thread.

my second one is clear and see through.

 
keep it simple looks like you are adding parts
I used a e clip and groove to hold the valve plate down on bothe versions the second one uses a piece of bycicle spoke for the valve rod.

Tin