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Small Chuck's Single Hit & Miss

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Superfast

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Marv,

Nick pretty much hit it on the head. Here is a pdf file with some models of how the fork works with the cap screw cam.

http://www.scottsrc.com/machining/forkdetail.pdf

The first 2 pictures show the cam in the "hit" position with the linkage fork in place. The 3rd picture shows the cam in the "miss" position.

In the parts drawings you can see that the fork guide has a slight "step" cut into it. The linkage fork rides in this step, when the cam is pulled away or not in the "hit" position, the step keeps the fork aligned. Hopefully the pictures clear it up for you.

Nick,

You are correct, sometimes the cam will strike the side of the fork, but as the crank rotates it drops into place and hits on the next stroke. I didn't use a roller/bearing style fork on my engine, mainly because of size. Instead it is simply a flat surface on the fork, seems to work pretty well. I made the original fork from brass and it is showing a little wear on it (probably cause I like the sound of the engine and can't quit running it!) from the cam "sliding" into position. If anyone wants to use this style of fork on their engine I would recommend building the fork out of steel, it should hold up a little better. I may end up going that way myself, but currently working on the new frame/cylinder design.

I wonder how the roller bearing style linkage would work with the cap screw cam design? Would it grab the edge of the bearing instead of "sliding" off a flat fork design?

Scott
 

NickG

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Scott,

Sorry, I missed the fork bit and just assumed it was a roller! :-[

I think you might be right, the fork will be better giving it a nice clean surface to slide off. I really like this design, it's a cam that maybe even I could make!

I love the way your engine works sounds exactly like a hit & miss. I've never seen anything like it at any shows over here, I can imagine it attracting a lot of attention on a club stand!

Nick
 

mklotz

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Scott,

Thanks for the clarification. I think I've got it now. I too was confused by the fact that it seemed the cap screw cam could strike the side of the fork. Now I see that it can but that it's acceptable.

Thanks again for the pictures.
 

dreeves

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Scott,

The pdf file you provided is great but I have a question on the workings. Is an earler post you had the parts between the two shafts



now it looks af if all of the parts are now on the crank making the engine run as a two cycle??
 

NickG

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dreeves,

Scotts engine was a 2 cycle as he didn't have any suitable gears. Chuck's original engine was a 4 cycle so Scott worked out a way of making the governor work with the 4 cycle version.

Nick
 

Superfast

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I have been busy doing other stuff around the house lately, but finally had sometime to get back to this little engine.

Here is the new look! It has a new base, frame and water jacket added. The water jacket was machined to use the existing cylinder I already had made. The cooling fins cut into the original design are hidden inside the new part. I added a brass trim ring around the base of the cylinder to kind of "trim" it out a bit. It still needs more cleaning and polishing but see what you think of the new look.

<a href="http://www.scottsrc.com/machining/hitmiss1.jpg"><img src="http://www.scottsrc.com/machining/thumbs/hitmiss1.jpg"></a> <a href="http://www.scottsrc.com/machining/hitmiss2.jpg"><img src="http://www.scottsrc.com/machining/thumbs/hitmiss2.jpg"></a> <a href="http://www.scottsrc.com/machining/hitmiss3.jpg"><img src="http://www.scottsrc.com/machining/thumbs/hitmiss3.jpg"></a> <a href="http://www.scottsrc.com/machining/hitmiss4.jpg"><img src="http://www.scottsrc.com/machining/thumbs/hitmiss4.jpg"></a> <a href="http://www.scottsrc.com/machining/hitmiss5.jpg"><img src="http://www.scottsrc.com/machining/thumbs/hitmiss5.jpg"></a>

Scott
 

putputman

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I really like what you have done to your engine. I have played the video many times and am fascinated with the hit & miss sound. I am starting to build one myself. I hope it turns out half as good as yours.

Now they say that there aren't any dumb questions, but this may be a first. ???

With this air operated engine, how would a 4 cycle run and sound any differant than your 2 cycle? It seems to me you only need a power & exhaust stroke. I wonder if you could even tell the difference in sound if you added the compression & ignition stroke. Maybe it is just for appearance.
 

NickG

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Putputman,

That's true, never thought of that! It would sound different withouth the hit & miss governor but with it, it shouldn't make any difference?

???
 

Superfast

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I would agree, 4 cycle and 2 cycle should sound the same with the governor. With a load on it the 2 cycle version should have more power available to run something, being it would hit every cycle.

Scott
 

NickG

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Good point! So it's more beneficial to do the 2 stroke and easier, if you're doing the governor.
 

putputman

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Thanks guys, I guess I'll take the easier route and go with the 2 stroke.
 

putputman

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Well I finally got my "Chuck's single hit & miss" done. ;D ;D I want to thank Chuck Fellows for the engine design & Scott "Superfast" for the governor design.

I run out of room for the governor, still can't understand why, so I redesigned it a little. I recessed into the flywheel and compressed it somewhat. It also uses a compression spring to operate it.

I can't seem to get that nice sharp firing sound like Scott gets on his little engine. Got any suggestion? ??? ???




 

NickG

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That is superb! :bow:

Sounds nice and sharp to me.
 

ksouers

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Arv,
Very nice. Looks like it runs quite smooth.

And I agree with Nick, sounded quite sharp to me. Very distinct sound.


Kevin
 

cfellows

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Very nice work, Arv. I think it sounds great. The difference in sound could be because it's a larger engine?

There's a few things that might alter the sound. You could experiment with different slave valve springs. Also, a sharper lobe on the cam might make some difference. This would result in a fast rise and shorter open time on the inlet valve. Finally, experimenting with the "exhaust pipe" would result in a different exhaust note. Maybe make it longer by adding a 90 degree elbow and adding a vertical piece?

Chuck
 

lugnut

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After watching the video of Arv's sweet little engine run I was wondering if the materials used to make the head and cylinders would make a differant sound? Aluminum, brass, steel or cast iron should all have some sound dampining effect.
Mel
 

Maryak

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putputman said:
Well I finally got my "Chuck's single hit & miss" done. ;D ;D I want to thank Chuck Fellows for the engine design & Scott "Superfast" for the governor design.

I can't seem to get that nice sharp firing sound like Scott gets on his little engine.
Great Engine and a great sound - such a sharp cut off shows the valves are very well constructed to me. :bow: :bow: :bow:

Best Regards
Bob
 

putputman

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Thanks guys, I'm pretty happy with it.

The cylinder is cast iron so maybe that does dampens a little. I notice a little whistle sound also. You probably can't hear it on the video because of the poor quality. I think I will fool around with the exhaust, like Chuck suggested, to see if that gets rid of the whistle and maybe improve the sharpness of the firing.
 

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