Compressed Air V8 Cirrus

[gbritnell]

Hi Chuck,
Nice work as always. I worked with magnesium in the shop many years ago. Every time we cut it we had the proper extinguisher and sand bucket available. Although I never saw an accidental fire I saw a few that were demonstrations and it's nasty stuff once it catches.
gbritnell

 

[cfellows]

Thanks for the kind words, George, although my work pales in comparison to yours!

I got the crankcase top, 2nd version pretty well finished today and I'm quite happy with the process and the results. I'll be uploading a video showing how I used my dividing head to position the work for hollowing out the inside.

I'm hoping these will have been the most difficult pieces and having them out of the way should make the rest of the project go pretty smoothly (famous last words!).

Chuck

 

[ShedBoy]

Looks good Chuck. Do you plan on running the crank in bushings, bearings or can it just run in the magnesium?

Brock

 

[cfellows]

Looks good Chuck. Do you plan on running the crank in bushings, bearings or can it just run in the magnesium?

Brock

Thanks, Brock. Current plan is to run ball bearings on each end and a 2 piece bronze bushing in the middle.

Chuck

 

[cfellows]

Here's a couple of videos. The first shows how I formed the semicircular cavity in the underneath side of the top crankcase half.

[ame]http://www.youtube.com/watch?v=gqCRwGf8EtI[/ame]

The second video shows it finished.

[ame]http://www.youtube.com/watch?v=yZNTW789r9g[/ame]

Chuck

 

[Don1966]

Great video Chuck thanks for showing how you did the inside of the crankcase. I have never done this but will give it a try. Love the progress you have done so far and interested in seeing more. Great work as usual.

Don

 

[gmac]

Chuck;
Great work, as always. I appreciate these types of videos because as a beginner, it helps me to get a feel for depth of cut and feed rates. The by the book numbers are fine but I guess I'm old fashioned - I like to feel, hear and smell things.

Cheers Garry

 

[steamer]

That works slick Chuck!

Dave

 

[cfellows]

Here's a pile of cylinders in the rough...

And here's the first prototype.

I decided to make the head integral with the cylinder. Simpler and easier to make. Sigh, 7 more to go!

Chuck

 

[cfellows]

Been working on the cylinders.

Part of the task was to use a slotting or cutoff tool to form the cylinder fins. I needed something that would cut a .050" slot and I didn't want to buy or use a standard parting tool, so I decided to make my own from a 1/2" square HSS tool bit. Here you can see the finished tool ready to cut a slot.

I didn't want to grind away the large chunk to to bring it down to .050" so I used a dremel with an abrasive cutoff blade to cut out the corner piece. Didn't take as long as I thought it would. Here's a picture of the partially cut out piece.

I had started grinding the tool bit to final shape using my tool and cutter grinder, but found that the cup wheel was just glazing over and heating up the tool bit too much. So I decided to make an attachment for my belt grinder and use that.

Here's a series of pictures showing how the fixture lets me swing the tool bit up to the belt, applying light pressure and pulling back briefly to let things cool.

The attachment allows me to adjust the bottom and side relief on the tool bit. It also cuts much faster and cooler than a grinding wheel. And, of course, the fixture keeps the angle constant, makes it easy to lift off the tool bit to inspect it and immerse it in water to cool it off. And, the finished cutoff tool did a very clean and fast job of shaping the fins and base of the cylinders.

Chuck

 

[kustomkb]

Your project is looking great Chuck.

That's a pretty neat way of scalloping out your case.

Your grinding attachment looks well thought and made too. I like the clean finish you get when touching up your tools on a sanding belt. Gotta make me one!

 

[cfellows]

Your project is looking great Chuck.

That's a pretty neat way of scalloping out your case.

Your grinding attachment looks well thought and made too. I like the clean finish you get when touching up your tools on a sanding belt. Gotta make me one!

Thanks, KB. I'm thinking about making a video to show the fixture and how it works.

One of the problems, particularly in multiple cylinder engines, is to make all the screw holes the same so the cylinders are interchangeable. I'm not particularly skilled at locating holes, so I made a drilling guide.

The guide has a spigot on the bottom which is a close fit in the hole in the crankcase. In the picture, I have a 1/4" cutting bit wedged in the back to hold the guide square to the vice and the case.

The drill guide has a recess on the top that is a close fit for the spigot on the bottom of the cylinder. The cylinder and the guide are held together square and tight in a vice to drill the matching holes in the cylinder.

Here are a few pictures of the crankcase with all the cylinders attached.

Chuck

 

[ShedBoy]

Moving along pretty quick there Chuck. Drilling jigs are great and if made thicker they are good for a tapping guide also
Brock

 

[gbritnell]

Hi Chuck,
Man, you're really ripping through this engine. At this rate you'll have it running in no time. Great work as usual.
gbritnell

 

[steamer]

Looks great from here Chuck!

I always liked the Cirrus 4

Dave

 

[cfellows]

Now here comes the connecting rods.

Kind of entering new territory with the size of these things. The blanks are 1.4" x 0.46 x 0.125. The big end screws will be 0 x 80 and they fit around a journal of 3/16". I'm going to have to come up with a fixture and a process to have any hope of making these things uniform in size and shape and completing them before before dementia sets in.

 

[cfellows]

There's a few postings that are missing from the change over of the website. I had finished the the connecting rods, then had to remake them because of a screwup!

I managed to reclaim my shop from the missus who was using it to paint a large piece of furniture. Here's 8 new connecting rods. Not perfect but good enough. I need to leave well enough alone or I'll wind up making a 3rd set! :hellno:

Next I think I'll give the pistons a go. I'm planning on using steel since they will be riding in aluminum cylinders.

Chuck

 

[Don1966]

Hi Chuck, still following here and you are moving pretty fast to me. You always amaze me with your fixtures and jigs. Great work as usual, remaking is just another step to learning.

Don

 

[kuhncw]

Nice work, Chuck. It wil be interesting to hear this one run. You get some pretty good sound out of your air engines.

Regards,

ChuckKuhn

 

[rhitee93]

I'm glad to see this build is still going. I am also looking forward to following along.