# Hoglet - Compressed Air Version



## cfellows (Apr 19, 2009)

Well, I figured it wouldn't hurt to make one or two pieces before I finished the plans. So, I got a good start on the crankcase sides for the Hoglet. I decided a 3/4 size would be best. These crankcase sides are 2 3/8" tall and 2 1/4" wide by 3/16" thick.

Some of you may have noticed that I have several projects in the air at once. When I get stalled on one, I like to have a second one to work on. I'm kind of stalled on the opposed 4 cylinder compressed air engine I started several months ago. In the meantime I finished Elmer's Open Column with reverse. Now I'm starting on another one. 

Anyway, I probably won't do much more on the Hoglet until I finish the drawings.


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## Jasonb (Apr 23, 2009)

That will be an interesting version of the engine.

Do you intend to use 1:1 ratio timing gears to just give an expansion and exhaust twin cycle?

Jason


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## cfellows (Apr 23, 2009)

No, I plan to use a 2:1 ratio so the engine will operate as a 4 stroke. I like to stick to original form and function as much as I can, albeit, highly stylized!

Chuck


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## cfellows (Apr 27, 2009)

I wanted to try out the method used by others where the flywheels are held on by slotted, tapered holes in the shafts and a tapered screw head to expand the shaft inside the flywheel. I'm happy to report that it works extremely well. Very tight, and the flywheels run dead true on the shafts. The taper is 10 degrees.

The original hoglet uses 4" flywheels, 3/8" shafts, and 10-32 SHCS. My engine will use 3" flywheels, 5/16" shafts, and 8-32 SHCS. I made the tapered d-bit from a 3/8" round piece of tool steel that was left over from a broken end mill. That stuff sure is hard to machine. Even with carbide tools, I had to replace the insert 3 times when cutting the taper. I cut part of the flat with a solid carbide end mill, but finally had to resort to my tool & cutter grinder to finish it off. It cuts well, although it does get kid of hot, even with oil.

Chuck


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## kustomkb (May 25, 2009)

Looks Good!

I didn't go quite to 10 deg. because I had another tool on hand, I will go to 10 deg before assembly.

I stumbled across some nice looking heads on photobucket, are they for this engine?

Kevin.


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## MatiR (May 25, 2009)

Nicely done, Chuck. I was concerned about balance using this solid version of the flywheel. Have you had a chance to check it out. Alas, I haven't got around to checking balance yet.

Mati


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## cfellows (May 25, 2009)

For balance, I had planned to drill a hole on each side of the crankpin, maybe 1/2" or bigger.

Regarding the heads on photobucket, they're not for the Hoglett engine. Those might be the heads for this 2 cylinder open column IC engine (that is yet to be finished).






Chuck


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## kustomkb (May 25, 2009)

I see, very nice!


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## MatiR (May 25, 2009)

cfellows  said:
			
		

> For balance, I had planned to drill a hole on each side of the crankpin, maybe 1/2" or bigger.



That's what I thought might work OK. I might plunge in with an endmill from the inside so it would not be visible. It should be easy enough to do the math to determine approximately what volume/mass of material should be removed.

M.


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## zeeprogrammer (May 25, 2009)

Did a search on the forum for 'hoglet' as well as a google.
Maybe I'm lazy and/or didn't dig deep enough...

What's the history/meaning/source for 'hoglet'?

Thanks.


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## joe d (May 25, 2009)

Zeeprogrammer

I've assumed all along that the diminutive in this case refers to being a model sized version of the V-Twin found in Harley Davidson motorbikes, AKA "Hogs". Now somebody who knows can destroy my comfortable assumptions :big:

Cheers, Joe


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## zeeprogrammer (May 25, 2009)

Ah. Once again I've exposed my ignorance.
Your definition makes perfect sense Joe.
Obviously...I don't know bikes.
More exposure to come...how else do I learn?

Thanks very much.


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## cfellows (May 26, 2009)

The original Hoglet model IC engine was designed and named by Randall Cox, a model machinist who lives in Wyoming. The name comes from the Harley Davidson v-twin engine. Harleys have been called Hogs for as long as I can remember, probably because of their generous size and weight, particularly compared to Japanese motorcycles (before they started emulating the Harley)

Chuck


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## itowbig (May 27, 2009)

i thought there was only one true motorcycle.  HOG  there is no substitute period heavy and loud


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## cfellows (May 27, 2009)

There is certainly something visceral about a Harley. I had a Harley 1200cc Sportser for about 8 years. It was scary fast and acceleration was breathtaking at just about any speed. I finally sold it because I kind of got scared to ride it, especially in Phoenix traffic. Several acquaintances were killed or seriously maimed on motorcycles in recent years so I gave it up.

Chuck


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## BronxFigs (Mar 20, 2013)

Mr. Fellows....

Just joined the forum recently, and just now read this thread.

Has there been any further progress done with this interesting design?  Drawings, videos, etc.

I hope this project didn't just die a slow death.

Frank


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## JeffF (Mar 20, 2013)

Can I ask how you turned the recess in the face of the flywheel?  It looks, by the machining marks that you did that on the lathe rather than on a mill and I would like to know how to do that.

Jeff





cfellows said:


> I wanted to try out the method used by others where the flywheels are held on by slotted, tapered holes in the shafts and a tapered screw head to expand the shaft inside the flywheel. I'm happy to report that it works extremely well. Very tight, and the flywheels run dead true on the shafts. The taper is 10 degrees.
> 
> The original hoglet uses 4" flywheels, 3/8" shafts, and 10-32 SHCS. My engine will use 3" flywheels, 5/16" shafts, and 8-32 SHCS. I made the tapered d-bit from a 3/8" round piece of tool steel that was left over from a broken end mill. That stuff sure is hard to machine. Even with carbide tools, I had to replace the insert 3 times when cutting the taper. I cut part of the flat with a solid carbide end mill, but finally had to resort to my tool & cutter grinder to finish it off. It cuts well, although it does get kid of hot, even with oil.
> 
> Chuck


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## cfellows (Mar 20, 2013)

I'm afraid this project has been sitting in a drawer for the past 3 or 4 years.  I still have all the parts and plan to finish it at some point, but don't know when.

The fly wheels were made in the lathe.  I used a standard triangular tip cutter to cut out the inner profile then switched to a boring tool to finish off inner diameter of the outer rim.

If you do a search of HMEM I think there is at least one and maybe more threads on making flywheels which show the process of cutting the recess.

Chuck


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## BronxFigs (Mar 20, 2013)

Mr. Fellows...

Were you going to make an engine that shared the same overall size, and, "look" of the original "Hoglet"?  How were you planning to get compressed air into the cylinders...rotary valves, ball valving, _your _valving methods?  

Frank


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## JeffF (Mar 20, 2013)

Thanks for the response!  It seems like I saw one thread at some point about how to do that, but I have searched all over the place and haven't found it again.

Jeff




cfellows said:


> I'm afraid this project has been sitting in a drawer for the past 3 or 4 years.  I still have all the parts and plan to finish it at some point, but don't know when.
> 
> The fly wheels were made in the lathe.  I used a standard triangular tip cutter to cut out the inner profile then switched to a boring tool to finish off inner diameter of the outer rim.
> 
> ...


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## cfellows (Mar 20, 2013)

BronxFigs said:


> Mr. Fellows...
> 
> Were you going to make an engine that shared the same overall size, and, "look" of the original "Hoglet"?  How were you planning to get compressed air into the cylinders...rotary valves, ball valving, _your _valving methods?
> 
> Frank


 
My engine was going to be 3/4 the size of the original.  I had planned to use a single overhead inlet valve actuated by a single pushrod  and use my spring loaded slave valve for the exhaust.  I will probably revisit the valve arrangement when I get back to the project.

Thx...
Chuck


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## cfellows (Mar 20, 2013)

JeffF said:


> Thanks for the response!  It seems like I saw one thread at some point about how to do that, but I have searched all over the place and haven't found it again.
> 
> Jeff


 
Here ya go...

http://www.homemodelenginemachinist.com/f26/how-do-i-recess-flywheel-face-20123/

Chuck


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## cfellows (Mar 20, 2013)

Here are pictures of the drawings I had been working from.  Not complete, but the proportions are correct.

















Chuck


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## BronxFigs (Mar 20, 2013)

cfellows:

Many, many, thanks for filling in the many blanks regarding your concept of this engine., and for taking the time to help. 

The added drawings/diagrams and new information are a great help, and I'm sorry this engine never got launched past the concept stage into the reality stage.  It would've been yet another great Fellows design.

Frank, et al.


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