Model Engine Maker

Engines => From Kits/Castings => Topic started by: cwelkie on January 05, 2016, 05:00:28 AM

Title: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 05, 2016, 05:00:28 AM
Hi everyone,
It has been a while since I've contributed but current circumstances have provided me with the time to catch up on some of the work and photos taken during my build of a set of Zimmerman castings acquired some time back.

In truth, I'd always wanted to build a Chenery Gypsy but haven't yet found a set of castings.  Cutting one out of solid, though possible, is being put off in the hope (however fading) of finding a set of castings one day.

This will be a little different than most build threads.  I wasn't going to bother.  After some time I realized that even if one photo or comment spurs someone on in their endeavours, it will have been worthwhile.  After all, much of what I have learned has come down to what is so freely shared here and who am I to take and not share what I can.

I'll be starting with the crankcase castings even though many of the smaller parts had already been made.  It seems I wanted to get those done before screwing up the courage to cut into these (irreplaceable?) castings.

So, we're off ... please forgive the poor lighting in some shots.

I started with the cylinder deck on the crankcase.  An end mill to start and a fly-cutter to finish to height.  This of course, was after smoothing the bottom surface and determining how much of an allowance to leave so the crankcase / oil-pan flange could be finished.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2335_1024_zpsuxjchzhx.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2336_1024_zpsblgdr767.jpg)

Once that was done I drilled and tapped the holes for the tappet seal hold-downs.  Then the tappet towers were cut to height, drilled, reamed and countersunk (with a shop-made countersink) for the  o-ring seals.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2337_1024_zpsoeashpga.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2338_1024_zpsmfdvqssv.jpg)

Small oil drain holes were put in the o-ring cavities before a frightening (for me) undertaking ... rough cutting the cylinder holes with a hole saw.  I've always been uncomfortable with hole saws; they've always seemed so ready to cause grief.  In the end it went well.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2340_1024_zpswutm9lns.jpg)

Once that done without calamity, a boring head sized the holes.  I then moved on to drilling and tapping the cylinder hold-down bolt pattern.  (yes the cylinder holes are supposed to be unevenly spaced  :))

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2341_1024_zpsox0jpixn.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2342_1024_zps2tffybk9.jpg)

After all that, I trimmed back the ends to "mark" how far to cut when I got to that.  It was then to finishing the bottom outside edge surfaces.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2346_1024_zpsc5xdofyp.jpg)

So far - so good:

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2343_1024_zpsnyrqahfa.jpg)

The next stage was getting the oil-pan and crankcase lined up for drilling and tapping the flange holes.  The oil-pan was cleaned up with lubed (WD40) wet/dry paper and CA glued to the crankcase for the drilling and such.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2348_1024_zpsflpnnrox.jpg)

The assembly could then be spaced, lined up and mounted to an angle plate to bore the end plate openings.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2350_1024_zpsdgivqa1z.jpg)

It was 'round about here that I took "a break" and made a faceplate for my faceplate ... The 12" faceplate supplied with my lathe is just too large and "clunky" for the kind of work I do.  I figured a smaller plate with T-slots would be much more useful.  It index centers onto the large faceplate.  Should look at drilling some more holes so I can mount it to the rotary table ... does it ever end?  ::)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2354_1024_zpsitsemkmh.jpg)

I think I'll leave this post where it is for know.  More to follow ...
All the best to everyone - everywhere!
Charlie


Title: Re: 1/4 Scale Cirrus MkI
Post by: petertha on January 05, 2016, 05:49:35 AM
Looking forward to your build Charlie. I've always had a soft spot for that engine design. I thought castings were rare as kryptonite though, so the only option was bar stock hogging like Paz did (link). Is someone re-making castings now or you've had them stashed in a vault somewhere? :)
http://homepage2.nifty.com/modelicengine/cirrus%20index.htm

What about the plans, I seem to recall one was featured as a build article in Strictly IC mag but maybe I'm mixing up Zimmerman with Chenery?
-Peter
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 05, 2016, 06:19:52 AM
Hi Peter - yes SIC ran a series on this engine built by Ron Calona.  I managed to be in the right place at the right time to acquire these castings as I don't think there are currently produced sets.

I too have spent many hours admiring "Paz's" work and shop-made tools.  Another self-taught inspiration for the rest of us ...

I believe someone in Winnipeg was in the process of doing some portion of the Gypsy casting set but have lost track of where that initiative stands today.

It would sure be nice if all of Mr. Chenery's designs ended up being cast again!
Title: Re: 1/4 Scale Cirrus MkI
Post by: Jo on January 05, 2016, 07:15:59 AM
Hi Charlie,

A very nice Gentleman by the name of "Joe" did a set of patterns for the Chenery Gypsy he sold a few sets of castings from these but I understand found it a bit of a hassle. The patterns are now with Kirt at Hemmingway so if you want a set you will have to ask him  ;).

I have a set of both the Chenery Gypsy and the Cirrus castings  ;D And will be following this thread with great interest.

Jo

P.S. Joe also did the Aeronca  :Love: patterns/castings which I also have a set of.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Jo on January 05, 2016, 07:49:52 AM
It would sure be nice if all of Mr. Chenery's designs ended up being cast again!

I missed that:

Kirt sell the Vee Twin castings and drawings.

A friend "Mike" does the Anzani castings (and a 6 cylinder version  :Love:)

I don't know about a source for the side valve castings.

Jo
Title: Re: 1/4 Scale Cirrus MkI
Post by: b.lindsey on January 05, 2016, 12:37:21 PM
This will certainly be one to follow Charlie. Lovely work so far on what appears to be a nice set of castings.

Bill
Title: Re: 1/4 Scale Cirrus MkI
Post by: zeeprogrammer on January 05, 2016, 02:10:31 PM
I'll be following too.

Excellent start.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Don1966 on January 05, 2016, 02:33:38 PM
Interesting engine, I will be following you also Charlie.

Don
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 05, 2016, 06:05:14 PM
Thanks all for following along and your kind comments.
Who else but Jo could torment us with virtually every casting set we mention?  :LittleDevil:

Jo - Here are a couple photos of my Aeronca ... no longer in casting form  ;) It was a fun but challenging build for someone of my experience at the time (even now?).

(http://i1196.photobucket.com/albums/aa405/cwelkie/Aeronca%20E118/DSCN0720_zpsvq4dzr2f.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Aeronca%20E118/DSCN0722_zpsxijmxajn.jpg)

I'm thrilled to hear that the Chenery Gypsy patterns are safe and in good hands.

... back to catching up.

Once the end plate bore was to size I removed the oil pan and used my small shop-made boring head to thin and shape the centre web.  It took awhile to step over a bit at a time but turned out fine in the end.  (Another tool on the perpetual list - a facing/boring head to Graham Meek's design.)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2352_1024_zpsyqxzs2bd.jpg)

Then it was on to turning it all over, truing it up and doing it one more time.  Here's the result after facing the tappet holes from the inside:

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2361_1024_zpsngpfkklv.jpg)

Next it was on to the fiddly job of fitting the oil tray to the oil pan.  I'd dimensioned the tray to the drawings once I was confident of the numbers.  This in involved using an adjustable angle plate to get the draft angle right (on the sides).
Once the tray was ready I proceeded to work the inside of the oil pan so that the tray settled in evenly and at the right height/depth.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2358_1024_zpsgcownvop.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2357_1024_zpsyvlr5nbe.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2360_1024_zpsfzcgs5dx.jpg)

Once the tray was in place I could drill and tap the four holes for securing it in place and then put the crankcase back on for drilling and machining the oil dipstick hole.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2359_1024_zpsjhcfl62v.jpg)

Now that the easy bits were done (?) it was time to tackle the end covers ... front one first.  I chucked it up using a chuck stop as extra security and it worked out fine in spite of the limited jaw contact area.  It seems I got caught up in the work and didn't take any progressive photos.

I did take one however of the rear cover plate on my new-fangled faceplate ... so much better than the monster beneath!

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2367_1024_zpszifjx3lh.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2381_1024_zpsfu9gt70z.jpg)

Looking ahead at coming operations there was a need developing for a number of special (to me) cutters.  These included a couple radius cutters, a 1 1/4" saw, a round-over cutter, valve seat cutter and a couple countersinks.  The block of aluminium is hiding the cylinder head behind the shiny surfaces.  This picture shows that I'd had the rear timing gear cover done by now as well.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2383_1024_zpsuzxnjqo1.jpg)

I think I'll leave this here for today and continue on with the cylinder head in another post.
Thanks for following along and sharing any comments or suggestions that come to mind.
Cheers
Charlie



Title: Re: 1/4 Scale Cirrus MkI
Post by: Tennessee Whiskey on January 05, 2016, 06:21:36 PM
Geez Charlie,  I'm gobsmacked,  the setups and ops are amazing  :ThumbsUp: :ThumbsUp:

Cletus
Title: Re: 1/4 Scale Cirrus MkI
Post by: Bjorn_B on January 05, 2016, 06:48:33 PM
This is very very nice! Hats off!
Title: Re: 1/4 Scale Cirrus MkI
Post by: fumopuc on January 05, 2016, 07:06:14 PM
Hi Charlie, I am following along and try to learn.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Dave Otto on January 05, 2016, 07:25:06 PM
I too have always liked this engine.

I will be enjoying watching yours take shape here on MEM; amazing work so far.

Thanks for sharing,
Dave
Title: Re: 1/4 Scale Cirrus MkI
Post by: Roger B on January 05, 2016, 07:57:46 PM
A very nice build and I like your setups  :ThumbsUp:  :ThumbsUp:

How big is the Aeronca? Is that a standard servo plug hanging down in the second picture?
Title: Re: 1/4 Scale Cirrus MkI
Post by: Jo on January 05, 2016, 08:14:48 PM
How big is the Aeronca?

 :naughty:

Jo
Title: Re: 1/4 Scale Cirrus MkI
Post by: Jo on January 05, 2016, 08:37:37 PM
Hi Charlie,

I thought you might find it interesting to compare your original Zimmerman castings to our "home cast" set  ;)

Jo
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 06, 2016, 01:15:03 AM
Thanks Jo for "scaling" the 1/4 scale Aeronca!
Those Cirrus castings look up to the task. Some subtle differences but lots of "margin" to work with.  No oil pan tray though ... but you probably aren't going to fly it inverted anyway  ;)  (I don't think Ken-ichi bothered with one either; on his cut-from-solid version.)

Roger - For fun here is a photo of the "magneto" with a scale alongside and yes that's standard servo connector.  (Between the hall effect in the "mag" and the ignition module.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Aeronca%20E118/IMG_7877_zpsbr3mx3oi.jpg)



Title: Re: 1/4 Scale Cirrus MkI
Post by: Art K on January 06, 2016, 02:50:11 AM
Charlie,
Seeing how far along you were I thought I'd missed it for a while. But I see you've just started. Wow...I've seen that Cirrus in SIC. I have to admit a fondness for aircraft engines. I will be following along.
Art
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 06, 2016, 03:50:02 PM
I'm humbled by such an talented and diverse group following along as I catch up with reporting progress on this build.  Thank you for the encouragement.

The cylinder head for this engine was (is?) the most intimidating piece for me.  The castings were bad enough due to their rarity but the head requires more machining operations than any other single part I've made.  A re-do would be ... let's just say, "frustrating".  For those that aren't familiar with this design, the head is one piece machined to provide the appearance of four individual heads.  It incorporates many angles, holes, rounded edges and many fins.

As shown earlier, I started with nice shiny block of 7075 that was finished to overall external dimensions.  What was  to be the top of the head was clamped to the mill table and the combustion chambers cut.  This was done with an end mill to start and sized with a boring head stepped over a few thou at a time.  Left over ridges were removed with discs of emery and a bore-sized rod spun in the mill with some lube.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2384_1024_zpstvuo5unb.jpg)

The valve positions were then machined for receiving the guides.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2385_1024_zpsppsatpjv.jpg)

A ball-end mill was used to open the cavity below the guides and above the valve seats.  The seats are to be cut directly in the head on this design.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2386_1024_zpsmxxte5p1.jpg)

Next up were the "spark access holes" and the cylinder/head bolt locations complete with a couple o-ring countersinks for the bolts that pass through the siamese intakes.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2387_1024_zpsoiolykdh.jpg)

A relief was cut around the perimeter with an end mill.  The radius cuts on the ends were done with the saw made to cut the fins with shown earlier.  The intake ports were drilled and the "flange gap" around them milled away while the head was clamped on its exhaust side.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2388_1024_zps784jwcxo.jpg)

The connecting passages to each intake valve were then machined using an end mill and the intake manifold flange stud holes drilled and tapped.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2390_1024_zpscabbzv9i.jpg)

Now it was time to drill the spark plug holes and setup the adjustable angle plate to knock off a corner.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2391_1024_zpsy3b8keip.jpg)

The angle plate setup was then spun to suit the exhaust flange locations so they could be done in pairs (i.e., two angled to the left; two to the right).  I was very glad that I'd taken the time to build the angle plate with enough accuracy to allow using the edges as references.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2392_1024_zpsnr49fvff.jpg)

This photo shows countersinking the head bolt locations with a shop-made countersink. (Over an inch deep!)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2395_1024_zpsi1por1rp.jpg)

Now we're back to the right angle plate to saw the illusion-creating gaps between the virtually individual heads  :Lol:

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2396_1024_zpshuq8zqm4.jpg)

It was now that the "rounding over" could begin ... virtually all the edges got the treatment from a D-cutter with the appropriate radius.  I was pleasantly surprised at the finish achieved off the cutter.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2397_1024_zpsnsglkoow.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2399_1024_zps15temtqg.jpg)

And that my friends is as far as I've gotten with the head ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2400_1024_zpshwbpf2jl.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2401_1024_zpstvckncx5.jpg)

... it is a relief to be so far - so good.  The remaining four perimeter corners need rounding over as well but they are at a different radius and I'll use the rotary table for them.  I did make a spring loaded pointed pin that I can use in the table centre to pickup some blind, light layout punch marks.  That (fin cutting) saw blade is still awaiting its workout as well.

That's as far as I got before breaking my (dominant!) wrist just before Christmas ... no shop time for awhile yet.  (I'll be really  :censored: if the healing delays my motorcycle season start!)

In the meantime, I'll take a few photos of the other parts completed so far (the rocker arms and their posts are particularly neat - in design) and get them posted.

Thanks again for being there!
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: joe d on January 06, 2016, 05:13:08 PM
Lordy lordy there sure are a LOT of set-ups in  that one piece!

Very much enjoying seeing this one, thanks Charlie.

Joe
Title: Re: 1/4 Scale Cirrus MkI
Post by: vcutajar on January 06, 2016, 05:14:20 PM
Wow Charlie, that head is really looking great. Thanks for showing all the steps.

Vince
Title: Re: 1/4 Scale Cirrus MkI
Post by: petertha on January 06, 2016, 07:25:31 PM
Looking good! I'd like to see a shot of your corner rounding (what you call D-cutter). I bought one for fear a home-brew would not work well. Assume its a single edge from oil or water hardening tool steel?
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 06, 2016, 11:32:13 PM
Hi Peter - here are a couple photos of the round-over cutter.  You're right, it  was made as any usual D-cutter and then hardened and tempered.  I used 3/4" O1 ... fresh out of 5/8"!  This time I remembered to leave a round section so I could measure approach to half-diameter ... as mentioned it presented a better than anticipated finish (please don't ask about feeds and speeds though - don't right that stuff down  :shrug:
Just holler if you've any other questions.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2416_1024_zpsmendvugv.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2417_1024_zpswh2ptcgp.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2418_1024_zps6um4bxwg.jpg)


And .. just because I felt such a fool for taking so long to figure out how to centre a "blind reference" on the rotary table here are some photos of the widget I threw together for that.  It is intended to pickup a centre punch/layout mark on a surface that is clamped to the table - kinda like a centering spigot that doesn't go through a hole.  It reuses an old MT2 Drill shank that I've bored to 0.5" to take a wide collection of such spigots.  This one just has a very short 60' pointy end and a spring under it.

Perhaps it's a helpful idea ...probably old news to the masters out there though.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2412_1024_zpsn2jssqbn.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2411_1024_zpsixtvrtzr.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/thumb_DSCN2410_1024_zps47iiby3c.jpg)

Cheers
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: tvoght on January 06, 2016, 11:38:15 PM
Thanks for showing the tools, Charlie. Both are interesting to me. I'm enjoying your build. Like others here, I admire the Cirrus very much.

--TIm
Title: Re: 1/4 Scale Cirrus MkI
Post by: 10KPete on January 06, 2016, 11:40:27 PM
That's a great idea!  :whoohoo:  I've been noodle-ing on how to center stuff on my RT once I have the mill going and that idea
is going in the tool box. :praise2:

Pete
Title: Re: 1/4 Scale Cirrus MkI
Post by: Don1966 on January 06, 2016, 11:47:27 PM
Beautiful results on the head Charlie and love the use of the D bit.

Don
Title: Re: 1/4 Scale Cirrus MkI
Post by: b.lindsey on January 06, 2016, 11:56:09 PM
That head is most impressive Charlie. Must be quite a relief to get it done without any mishaps. Beautiful work!!

Bill
Title: Re: 1/4 Scale Cirrus MkI
Post by: Dave Otto on January 07, 2016, 12:53:21 AM
Yes the head is looking real nice! Lots of operations in that part.

Dave
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 08, 2016, 07:59:00 PM
Thanks all - yes, it is nice to have the head this far along without mishap or unintentional "decoration".

As promised earlier, I've taken photos of the other parts already completed and will post them as well.  They probably won't be as interesting (no setups) but at least all the bits will be in one place so-to-speak.

I'll start with another part that required a number of setups, blind holes and a few tense moments with tiny drills.  I decided to use a two-jet carb design that was publish in SIC years back.  I think it was by Jerry Howell.  No real reason for doing it different than the Zimmerman carb; just wanted to build this two-jet example.  Time will tell how it works on this engine.  (I did revise the venturi size to be in-line with that used on the Zimmerman drawings ...)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2420_zpscuwtgy0u.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2421_zps7crkrn8y.jpg)

The oil pump is driven straight off the back of the crankshaft.  A tiny cross-pin fits into a socket head screw in the back of the crank.  The tapered ends of the pin engage the internal angles of the screw.  Simple universal joint ... The gears were cut using a shop-made hob - 48DP - aka "tiny".  The inlet and outlet nipples are to plan but I don't think they'll stay.  The pump body is threaded so I reckon they'll be changed to metal tube fittings in the end.  These are good for testing and run-in though.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2422_zpsmmxg6rxx.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2423_zps7po6fowf.jpg)

The dipstick is a simple bit but a nice distraction as simple bits can be.  The blade hasn't yet been "calibrated" ... it was the stainless steel spine of a wiper blade in a past life.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2424_zpsos76x8iy.jpg)

These are the clamps that hold two crankcase breather tubes in place either side of the forward crankcase.  They were a fabrication from solid and tubing; silver soldered/brazed together.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2425_zpsfytjuavu.jpg)

This is the breather itself.  It threads into an angled hole on the front cover just above the crankshaft.  It too was a fabrication; two tubes and a bit of solid all silver soldered/brazed together.  There were some anxious moment using some relatively large cutters on pretty small parts.  I only had to make two of these to get a keeper.  The aluminium cap unscrews to allow oil to be added to the crankcase.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2426_zpswiigbgsb.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2427_zps1b3yogdv.jpg)

I'll leave off here for the moment ... a few more photos of the valve train pieces and cam gears and then I'll be caught up.
Charlie


Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 09, 2016, 04:01:22 PM
Okay - more more go and then I'll be caught up until I can get back into the shop.

Here is a "family picture" of some of the valve train pieces.  Rocker arms; their posts, shafts and bushings.  The rocker arms started as full diameter discs that were drilled and reamed for the pivot hole and the various radii.  The side radii were cut on the lathe; each side of a disc in turn on a fixture.  The rotary table was then used to cut the arcs in stages on another fixture that used index pins in each of the reference radii holes.  The posts also started as discs and were a combination turning, rotary table smiling exercise as well.  Yet another fixture on the table to finish the upper radius.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2428_zps4cyzica3.jpg)

Here is a photo of one assembly resting in it's ultimate destination on the as yet unfinished cylinder head.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2429_zpseiimaesx.jpg)

A few more bits and bobs ... tappets, valve spring retainer cups, tappet oil seal retainers and the oil pan plug.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2430_zpshht4cs9v.jpg)

Here we have the camshaft gear train.  I made the camshaft gear adjustable over a few degrees in part for the practicality but mostly because I think it looks right.  These gears were also cut by hob - 32DP.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2431_zpslgsnyl58.jpg)

A closeup of the engraving marks done by a tiny ball cutter in the mill (while on the rotary table of course).

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2432_zpsny2klxut.jpg)

Here's the backside of the camshaft gear.  I've left broaching the keyway in this gear until it's position can be determined on assembly.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2433_zpsh8t0tkrn.jpg)

Thanks for looking in - sorry for the lack of setup pictures to go with the last lot ... consequence of waffling over posting the project.
Charlie





Title: Re: 1/4 Scale Cirrus MkI
Post by: zeeprogrammer on January 09, 2016, 04:05:39 PM
Wow. That's some nice stuff there.  :ThumbsUp:
Title: Re: 1/4 Scale Cirrus MkI
Post by: Jo on January 09, 2016, 04:06:46 PM
Now you are worrying me  :paranoia: this is one of my engines for my future retirement when I hope might have a better idea what I am doing but  :o

This is all good stuff Charlie, I can tell I am going to have to work up to this engine  ;)

Jo
Title: Re: 1/4 Scale Cirrus MkI
Post by: petertha on January 09, 2016, 04:56:00 PM
Very nice!

Can you elaborate on your rockers & tappets & overall hardening strategy for valve drive train. Tool steel? Fully hardened vs. just on the ends where it needs it? Are you alternating hardened to non-hardened mating surfaces to confine wear to certain parts? I'm just making up a jig plate to mill the overall profile, but also serve double duty to profile the tricky little rocker/valve sliding face radii. I have no idea if this is going to work. Would love to hear how you approached this aspect on your rockers.

Re the 2-jet carb design, do you mean like a main & idle fuel circuit, or 2 main fuel jets for better flow/atomization or something?
Title: Re: 1/4 Scale Cirrus MkI
Post by: petertha on January 09, 2016, 05:06:44 PM
You mentioned building this angle plate yourself. I'm very interested to know more details. Is it from your own design or casting kit or? Its such a nice low profile design. The commercial ones I've seen appear much larger, expensive & I get the impression more for grinding setups vs. milling operations. Sorry for all the questions, feel free to post separately in Tools section or wherever so I don't off-topic your Cirrus post.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Don1966 on January 09, 2016, 05:40:43 PM
Nice progress Charlie and I would like to see more operation photo of how you go about making these gorgeous parts. You made your own  gears and do you have photo making them? I am also curious of you angle plate.

Don
Title: Re: 1/4 Scale Cirrus MkI
Post by: b.lindsey on January 09, 2016, 06:21:41 PM
Most impressive work Charlie....even all the little bits!! Looking forward to more now in real time :)

Bill
Title: Re: 1/4 Scale Cirrus MkI
Post by: smfr on January 09, 2016, 06:49:34 PM
Those are some amazing-looking parts, Charlie!

Simon
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 09, 2016, 07:01:17 PM
Thanks everyone for your kind comments.
Jo - you won't have any trouble with this build given what I've seen you take on with great success.  All the bits are just little projects by themselves ... eventually there are enough to assemble an engine.

Peter - no worries about all the questions; that's why we share this stuff anyway isn't it?  I'll try the easy ones first.

Don - sorry no photos of cutting the gears.  Best I can offer are some of the arbor and hobs used to cut them.  Let me know if that is of interest.  The gear blanks were on an arbor in the vertically mounted rotary table.  The hob was on another arbor in the mill spindle.  Not terribly difficult just time consuming.  Very grateful for power feed and having converted the rotary table to receive a stepper motor drive.

The carb design is a two-jet arrangement, that is a mixture control for both idle and high speed.  To a large degree that's what attracted me to it - and the fact that it was well thought out from a "buildability" perspective.

I am only planning to harden contact areas on the rockers and the tappets.  The tappets are made of drill rod (tool steel) so that's easy.  The rockers are of cold-rolled so I'll be using Cherry Red case hardening compound for them.  I used this material when I hardened the saw I showed earlier and it worked very well ... be sure to have plenty of ventilation though.  I don't anticipate a need to harden much else in the valve train so I guess yes, I'll be hardening one side of a contact pair and leaving the other "soft".

The adjustable angle plate was actually done in anticipation of this build.  It has however seen a great deal of use for many other "little things".  Between the plate and a digital angle gauge I'm feeling right spoiled.  I purchased castings for the angle plate from College Engineering in the UK.  I also brought over one of their Keats Angle Plates to spread the per unit postage  ;D  The castings were of very good quality.  The Keats hasn't been used as more than an extra right angle plate yet but it is nice have around just for that.  Harold Hall (from the UK) did an article in Model Engineering Workshop on both - there may be more information on his website. Let me know if you'd like some pictures of it/them.

Now the tricky bits, the rocker arms - and more "feeling bad" for not taking pictures of the setups ... but I'll try to describe them best I can.
First off, the drawing detailed the radii centres for the nose and other important features.  The 0.313 hole near centre is the pivot hole.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2435_zpsozzg4kyf.jpg)

Each disc of material that was going to end up being a rocker arm was sliced off the stock, faced and dimensioned to thickness.  The centre pivot hole was also drilled/reamed while in the lathe.  They could then be put on the rotary table to have an index pin hole drilled and a clearance hole drilled for a machine screw hold-down.

A lathe holding fixture was then made up with a matching centre pivot hole, index pin hole and a thread hole for the machine screw anchor.  Here is the lathe fixture:

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2436_zpsaiux6xtg.jpg)

Now a radius cutter could be used to cut the groove in both sides of all the rocker blanks.  After this each blank had a shallow curved depression all the way around the blank on both sides.

Some where in here I made a index plate for use on the rotary table.  This plate has a centre pivot hole of the same dimension as the rocker arms, an index pin hole to match the one in the "lathe fixture" and two more to pickup the nose radii centres.  Like this:

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2437_zpsfhovce4r.jpg)

Here is another picture of the fixture plate on top of the "lathe fixture" with both index pins in place:

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2438_zps3rb38yvl.jpg)

With the rotary table centred under the spindle I could now place the rocker arms on the fixture and on each of the critical centre points in turn to cut the arcs.  There was some messing around with moving clamps for every operation and some planning ahead required to be sure there was something to clamp on.  In the end I think it worked out pretty well - even the "spare" made it through without mishap.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2439_zpsbzewzd3p.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2440_zpsgnu8du4j.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2441_zpsrcrsrzlz.jpg)

All the best everyone!
Keep the questions coming - glad to be of any small assistance.
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: 10KPete on January 09, 2016, 07:12:11 PM
I would be very interested in seeing pics of your angle plate as I also have a low overhead mill and frequently need to do
angle cuts that can't be done in the vise or flat. Cutting a piece of wood for each job is problematic!

Pete
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 09, 2016, 10:08:34 PM
So here you go (Pete, Don and Co) ... more about the adjustable/tilt angle plate I used.

As mentioned, the castings came from College Engineering.  They have two sizes - the one I have is the larger of the two.  Here is a link to the web page that lists their angle plate castings:

http://www.collegeengineering.co.uk/AnglePlates.htm

Harold Hall does have a page on his website about this angle plate as well:

http://www.homews.co.uk/page326.html

I'm sorry I couldn't level it for a better idea of its height in that plane ... only so much I can do with one hand (clamping bolts too tight).  These pictures might help.  It is sitting on a 9"x42" mill table (Bridgeport clone).

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2442_zpsqnz3jcjt.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2443_zpst9icz4s6.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2445_zpszkz55mkr.jpg)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2446_zpscxealpkp.jpg)

One thing I plan to do to mine is drill and tap some holes along adjacent edges to act as a fence in both directions.  This will help not only in the setup of multiple parts but also in the setup of a single part that needs to held to a reference.  (It would also help to keep things from sliding off   :LittleDevil: )  I've also been hemming and hawing about adding T-slots as Mr. Hall did but have so far been satisfied with the slots.  (I did machine the underside around the slots so that I can T-nuts anyway - they just aren't captured.

Charlie

Title: Re: 1/4 Scale Cirrus MkI
Post by: 10KPete on January 09, 2016, 11:10:04 PM
Thanks for the pics Charlie! I kinda figured it was a simple thing but one never knows, do one?

That's a neat engine you're building and the workmanship is great. I love the details.

Pete
Title: Re: 1/4 Scale Cirrus MkI
Post by: Don1966 on January 09, 2016, 11:32:51 PM
Charlie thanks for the feedback and I do like the angle plate........ :ThumbsUp:

Don
Title: Re: 1/4 Scale Cirrus MkI
Post by: Graham Meek on January 12, 2016, 03:20:21 PM
Hi Charlie,

I have just been reading this post for the first time. I like the work you are doing and I was really taken by the vernier adjustment on the camshaft gear as well as the lovely sculpted rockers. I shall make a point of looking in on this post more often

My best regards
Gray,
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on January 13, 2016, 03:45:23 PM
Thanks Graham for the kind comments.  I too was quite pleased with how those pieces turned out.
I've recently spent a few hours studying your facing/boring head design and will need some serious determination not to be distracted by it ... at least until I can get the cylinder head finished.
Cheers
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: Graham Meek on January 13, 2016, 04:57:28 PM
Hi Charlie,

I see the mention to my boring head earlier on in your post. If it is any help I made one for a friend just before Christmas and it took me about 30 hours in total.

My best regards
Gray,
Title: Re: 1/4 Scale Cirrus MkI
Post by: Tjark on January 13, 2016, 06:25:07 PM
Charlie, a beautiful project.
My skills are far from this kind of work.
Will follow you progress.

   Tjark.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on February 14, 2016, 11:14:33 PM
Well the wrist has healed well enough to get back in the shop, give it a bit of a tidy-up and get back to the cylinder head.  Even managed to get a couple more chuck stands thrown together to hold my faceplate and small 3-jaw properly.

Here is a picture of the spring loaded centre I put together for the rotary table.  I marked and centre punched the locations of the corner radius centres.  It was then easy to settle the spring loaded centre into the centre punch mark and clamp the head down for rounding over.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2448_zpslnijraee.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2448_zpslnijraee.jpg.html)

Once the head was lined up and clamped down there was nothing for it but to start cutting the grooves.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2450_zpsyu7ijvbq.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2450_zpsyu7ijvbq.jpg.html)

I cut the fins all four sides without moving the head - figured it was best way to ensure the beginning and end of the groove ended up in the same place.  I then mounted the head with the exhaust side down to cut all the grooves I could reach including finishing them to the same depth on the ends.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2451_zpsndhjppe3.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2451_zpsndhjppe3.jpg.html)

Then the head was flipped over and the last two grooves cut in ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2452_zpsjhu7pcep.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2452_zpsjhu7pcep.jpg.html)

After a bit of tidying it looks like a keeper ... as mentioned before, I reckon this piece now holds the record for the highest number of machine operations and setups in a single part.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2453_zpskpds5vf9.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2453_zpskpds5vf9.jpg.html)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2454_zpsksaijrmq.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2454_zpsksaijrmq.jpg.html)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2455_zpsssw8sntf.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2455_zpsssw8sntf.jpg.html)

I managed to get the crankshaft and cylinder stock cut to length as well so I guess I'll have to flip a coin to see which bit is next.
As always - hope this is of some interest.
Cheers
Charlie



Title: Re: 1/4 Scale Cirrus MkI
Post by: zeeprogrammer on February 14, 2016, 11:28:45 PM
Nice looking parts!!

I didn't know about your wrist. Hope all is well now.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Dave Otto on February 15, 2016, 01:07:45 AM
Impressive piece of work Charlie!

You have got be be pretty darn happy with that.

Dave
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on April 11, 2016, 12:04:42 AM
Gosh - it's been almost a month since any update on this thread ... it must be motorcycle season  ;D
I've made some progress on the crankshaft though.  It started with a piece of annealed 4140 that was available in flat stock of the right dimensions.  That saved some work compared to starting with full round 1144.  So, after a layout session and some time for the subconscious to double check for any errors it was time to drill some holes and cut off some extra bits.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2460_zpsa45boiik.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2460_zpsa45boiik.jpg.html)

I then setup the blank on the mill using a vertically mounted rotary table and tailstock.  I wanted to try the technique of milling off the square corners to avoid as much interrupted cutting as possible.  It worked fine but I'm not sure the bother of setting it all up was worth it.  I suppose one would have to do two cranks, one each way, to really know.  In any event, it made setting the journal spacing easy.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2463_zpsdm7i7axg.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2463_zpsdm7i7axg.jpg.html)

You might just make out a centre fixture I'd made for use on the driven end of the crank.  It was from an Model Engine Builder article and I am happy with how secure it held the end of the crank and made changing centre easy and secure.  Here the crankshaft to be is in the lathe having the journals cut and "webs" cleaned up.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2465_zpsq6lbmbhc.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2465_zpsq6lbmbhc.jpg.html)

The journals polished up nicely with some emery and then wet/dry.  Even got them all within 1/4 thou of each other (near as I can measure anyway.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2467_zpsralfvpbd.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2467_zpsralfvpbd.jpg.html)

Once all the between centres work was done on the journals it was time for that irreversible step of "cutting off the ears".  I did the prop end first so I could still drive the crank using the fixture.  Supported the end with a fixed steady to cut the threads and taper.  Then the "back end" was cut off, cleaned up and drilled for the cam drive gear screw and shoulder.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2471_zpsvxaylbis.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2471_zpsvxaylbis.jpg.html)

After all was said and done, the bearings and the gear slipped on with just the right amount of resistance.  Pleased about that.  (Reminds me of a flying instructor from years ago ... "trust your instruments", he'd say)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2473_zpsfmvcfctm.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2473_zpsfmvcfctm.jpg.html)

While fiddling with crankshaft bits, might as well do the prop hub and washer.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2474_zps3yfep9i2.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2474_zps3yfep9i2.jpg.html)

... and they fit too!

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2475_zpstuh9gqld.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2475_zpstuh9gqld.jpg.html)

Now that I've caught up with these photos, next up will be the cylinders.  I've roughed out a mandrel to hold them while turning the external features.  I'll finish sizing the mandrel once I bore all the blanks to size (slitting it seemed to have relieved a little bit of stress in the material).  Here's hoping I can get all four cylinders to the same size; within reasonable limits of course.  ;)

Until next time.
Charlie

Title: Re: 1/4 Scale Cirrus MkI
Post by: gbritnell on April 11, 2016, 12:11:16 AM
Really nice work Charlie!
gbritnell
Title: Re: 1/4 Scale Cirrus MkI
Post by: Tennessee Whiskey on April 11, 2016, 12:22:38 AM
Now that is one sweet crankshaft and a super job of achieving it  :ThumbsUp: :ThumbsUp: :cheers:.

Cletus
Title: Re: 1/4 Scale Cirrus MkI
Post by: b.lindsey on April 11, 2016, 12:37:10 AM
Both the heads and the crankshaft are beautiful examples of machining Charlie. Well done!!

Bill
Title: Re: 1/4 Scale Cirrus MkI
Post by: zeeprogrammer on April 11, 2016, 12:49:54 AM
 :o

Just don't know what to say. Wow...what a part.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Dave Otto on April 11, 2016, 12:53:42 AM
Nicely done Charlie!

The crankshaft and prop hub both look great.

Dave
Title: Re: 1/4 Scale Cirrus MkI
Post by: petertha on April 11, 2016, 07:51:32 PM
Very nice Charlie.
When you say 'annealed 4140', do you mean it was purchased that way, or you did some baking on you own?
Anything special about cutting tool type/geometry or it machined pretty well with conventional tooling?
Title: Re: 1/4 Scale Cirrus MkI
Post by: Roger B on April 11, 2016, 08:07:17 PM
That's another very nice bit of fabrication  :praise2:  :praise2:
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on April 12, 2016, 01:09:19 AM
Thanks all for the encouragement and providing the incentive to keep moving forward ... I get to feeling guilty if I haven't put anything up for awhile.

Peter - the 4140 was purchased in the annealed state.  Was rather surprised to see it available in the rectangular section.  It cut beautifully on the powered hacksaw and drilled easily.  I admit to being challenged on the surface finish though.  I never did get the surface finish I'd hoped for or expected on the webs.  Tried carbide and HHS; different speeds and feeds.  Had the part made before I found the sweet-spot.

For the journals I got the best result with a bi-furcated grind on a HHS cutoff blade.  (added maybe 5 degrees back rake)  The finish wasn't bearing-ready but that was sorted easily and quickly with a couple grades of emery and then a polish with some 600 wet/dry supported by the back of some worn energy strips.  I was surprised at how quickly the journals finished - good thing I left a good 2/3 thou for finish work.

Will I use it again ... only to use up the extra material brought in (always make sure I have "re-do stock"!).  It's back to stress proof for me.  If I try something new next time it will be to anneal some cold rolled rectangular cross section in the shop.  (Managed to re-purpose a ceramic kiln a few years back ... )

Long winded response - hope it's of some use.
Cheers
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: petertha on April 12, 2016, 08:01:13 PM
Thanks for useful comments. Exactly what I wanted to know. Just about to try stress proof myself for the first time, so good to know you came to this conclusion.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on May 08, 2016, 01:49:43 AM
Well ... I'm still at it; albeit very slowly.  This time I'll share the journey in making the cylinders.  They are of 12L14 (Leaded steel) only because I've had good luck using it for cylinders before and I very much like the relatively stress-free way one can cut (thin) fins in it.

I started with four "blanks" that were turned to length plus a bit and then bored/honed to within a thou of target bore diameter.  I plan to lap them to final dimension after I sort out if I'm going to colour them (black) or not ... but that's another story.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2476_zpsohzpzrlh.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2476_zpsohzpzrlh.jpg.html)

The arbor was turned to a few thou oversize, then slit (free-hand on the bandsaw).  The "wedge screw" is just a socket head cap screw with a 60 degree taper turn on the bottom of the head to match a taper cut with a large centre drill.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2477_zpsbofuga6c.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2477_zpsbofuga6c.jpg.html)

Once I was ready to work on the cylinders I put the arbor into the lathe, tightened a thick washer on the end to hold the split sections in place and finish turned the OD.  Then it was down to cutting away the bits that didn't belong and on to cutting the fins.  I ground a HSS blank into a 0.050" wide tool deep enough to reach in 0.300" or so.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2480_zps3gorx18c.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2480_zps3gorx18c.jpg.html)

Then the cylinders could be turned around, this time spaced away from the arbor to provide an easy reference for cutting the overall length and upper spigot depth.  Also used the same setup for each cylinder to cut the inside, upper chamfer and the angle on the lower fins.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2493_zpss5lbb0hu.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2493_zpss5lbb0hu.jpg.html)

... and then there were four cylinders.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2495_zpsyzy7h2dm.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2495_zpsyzy7h2dm.jpg.html)

To fit the crankcase spacing, flats are cut on the cylinders to provide the required clearance so a walk over to the mill was next.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2496_zpsds7mweow.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2496_zpsds7mweow.jpg.html)

With great satisfaction, they fit the crankcase with the same subtle gap.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2497_zpscbxrqoo5.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2497_zpscbxrqoo5.jpg.html)

At this point I just couldn't resist digging out the head for a look-see ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2498_zpszzvmhql9.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2498_zpszzvmhql9.jpg.html)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2499_zpsy2mlbbdk.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2499_zpsy2mlbbdk.jpg.html)

So far so good - everything seems to be lining up nicely.  Guess I need to go on the prowl for some 18 gauge sheet steel for the cylinder spigot/spacing plate ... or find that length of 3/8" 2024 for the connecting rods ... or decide if I should blacken the cylinders or not ...

Thanks for looking in.
Charlie





Title: Re: 1/4 Scale Cirrus MkI
Post by: b.lindsey on May 08, 2016, 01:57:30 AM
That is a fine family shot there Charlie!!  I don't blame you for getting out the heads to see how it will look. Beautiful machining on those cylinders too!!

Bill
Title: Re: 1/4 Scale Cirrus MkI
Post by: Don1966 on May 08, 2016, 02:03:22 AM
Just catch up Charlie and that's is some real fine work. Those cylinders are a treat........ :ThumbsUp:


 :popcorn: Don
Title: Re: 1/4 Scale Cirrus MkI
Post by: 10KPete on May 08, 2016, 02:07:50 AM
Sweet!!   :cheers:

Pete
Title: Re: 1/4 Scale Cirrus MkI
Post by: Art K on May 08, 2016, 03:51:04 AM
Charlie,
Fantastic job on the head. I'm still following along, good work.
Art
Title: Re: 1/4 Scale Cirrus MkI
Post by: fumopuc on May 08, 2016, 10:19:40 AM
Hi Charlie, thanks for showing it, great progress and nice pictures.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Graham Meek on May 08, 2016, 07:51:37 PM
Hi Charlie,

You certainly have been busy since I last looked in, you should be justly proud of your achievement.

My best regards
Gray,
Title: Re: 1/4 Scale Cirrus MkI
Post by: Roger B on May 08, 2016, 08:01:16 PM
That's looking good  :praise2:  :praise2:
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on May 09, 2016, 02:45:15 PM
Thanks everyone for coming along on this journey.  Like many things - it's better when shared.

I did manage to get the cylinder spigot plate done yesterday - sorry no photos yet - and it looks like it's a "keeper".  Now I just need to get my head wrapped around exactly how it's intended to be used.  The drawings have no detail showing if the plate is intended to go directly under the head or on top of the cylinders.  There is supposed to be an o-ring sized to match the OD of the cylinder spigots in there somewhere too.  I can't imagine using an o-ring in lieu of a sheet head gasket ... The length of the spigot seems to short for both the plate and the o-ring - a great deal of compression needed on the ring to seat the head.

Oh well; another lesson in looking further ahead and not blindly following drawings.

BTW, have any of you used the Caswell Black Oxide kit?  Is it as easy as made out to be in their videos?  Also wondering about the most effect way to clean parts (short of an ultrasonic cleaner) in preparation for treatment.  Looking at this product because it is available from a Canadian supplier ... shipping "creepy chemicals" across the 49th parallel might be interesting.

Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: petertha on May 10, 2016, 06:17:05 AM
Very nice progress Charlie. I haven't used the Caswell kit myself, only the 'regular' blackening stuff with 'Meh' so-so results. Its black all right, but its very thin & slight scratching is all that's required to show metal. One kit came from KBC Tools, the other was from a local jewelry supplier. They both looked & smelled the same and were meant to be used un-diluted as-is. The Caswell is interesting because it indicates 1:9 distilled water dilution formula, which infers its much stronger than what I have.

My experience has been that degreasing is the paramount issue. I'm not sure if an ultrasonic would do much better. I always envision an oil skim on the surface of the water. Yes its been removed from the part, but then you risk re-coating the part again on the way out of the tub? My best results were scrub with dish wash detergent soapy water, blow dry immediately, then  successive baths in brake cleaner & wipes with paper towels. Regular mild steel for some reason looks better to by eye than 12L14 all thing equal. Not sure if its the lead content of 12L14?

Another issue is sealer procedure. My kit recommends first a water bath after chemical dip, wipe off, then application of 'their sealer'. But the water wash inevitably gives it a somewhat brownish rusty tinge & especially in nooks & crannies which is hard to get out. It does come off with rubbing. Maybe I should be using distilled water vs. tap water? The sealer gave it a slight lustre but it wasn't like OMG spectacular. Not sure what it is but seems like some oily waxy liquid. For some reason on who-cares machine tool parts I skipped the water altogether, slightly buffed any excess black with clean cloth & then immediately wiped with WD40. To tell you the truth I like it a bit more & less fuss.

I assume you are considering this blackening for your cylinders? One thing I can pass on, I've been making liner 'prototypes' for my radial: 12L14, CI & 1140-SP. The two 12L14 liners machined nice, one was WD40 covered in baggy storage. The other was dry. A few months later the dry one has rusty spots starting on it & Calgary is bone dry humidity. So I'm a bit worried by that long term in a methanol fuel environment. I'm familiar with after-run oil for RC stuff so I think that would be part of the storage ritual. I've seen other IC builders use 12L14 cylinders but have had them professionally gun blued/blacked with the hot bath nasty chemical bit. Or they were liners where the OD is sealed against the cylinder & gasoline fueled, so maybe not as bad as methanol? So just a heads up, maybe test this yourself. I'm no expert.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on May 10, 2016, 02:52:54 PM
Thanks for sharing your experiences with blackening 12L14 Peter.  I'm glad to know that you've had some positive results.  Perhaps this is like many other things, I'll just have to dive in and give it a try.  There are lots of bits and pieces of tooling around the shop that will make good test samples.  I even have a couple/three left over cylinders from previous projects as a final test.

I'd agree the cleaning is likely the key to success and the rinse water (if used) should be as "pure" as possible.  Distilled would probably be better than tap water.  One of those car wash filters on a hose (Turtle brand I think) might be a good thing - no spots on the car ...  Or maybe I'll have to bring some RO water home from "work".

Cheers
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on July 01, 2016, 11:59:46 PM
It has been ages since I last posted anything about the Cirrus.  Too many of life's distractions getting in the way I guess.  There has been some progress however small.  In my world, any progress at all counts.

I had left off trying to decide what to tackle next and ended up doing the cylinder spigot plate.  It is a thin plate that acts as a sort of cylinder spacing stabilizer if that makes any sense.  The head sits directly on top of the cylinders.  The cylinders each have a spigot long enough for an o-ring and then the plate.  Anyway - I found a piece of steel of the right thickness and re-purposed it by cutting all the right holes and stripping the paint off.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2500_zpshbiv7qxh.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2500_zpshbiv7qxh.jpg.html)

Next I tackled the connecting rods.  All the blanks and the radius cutting tools needed got prepared in advance.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2502_zpsiizijzrr.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2502_zpsiizijzrr.jpg.html)

Then some centres were put in each end and the big-end cap screws were drilled to tapping and clearance sizes before cutting the caps off.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2503_zpsmdvmvyvl.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2503_zpsmdvmvyvl.jpg.html)

Once the outline was roughly cut back it was into the lathe to turn each end to size while mounted on centres.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2504_zpswduewddm.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2504_zpswduewddm.jpg.html)

... might as well do all the rods together.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2505_zpszux3ljbl.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2505_zpszux3ljbl.jpg.html)

Then the middle section diameter was turned on all the rods.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2508_zpskqk0gnlb.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2508_zpskqk0gnlb.jpg.html)

Another family shot; this time with the double-ended arbour used to turn the faces of each rod end.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2507_zpskrbqijmi.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2507_zpskrbqijmi.jpg.html)

Next the radii at each end were turned with 1/4" and 1/2" radius tools.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2508_zpskqk0gnlb.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2508_zpskqk0gnlb.jpg.html)

Here is a view of the rod end being trimmed back to reduce the face diameter.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2509_zpszaezv8i1.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2509_zpszaezv8i1.jpg.html)

Time for some rotary table work to round off the ends and make them pretty; used the same arbour.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2510_zpsfncem0tl.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2510_zpsfncem0tl.jpg.html)

Almost done ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2511_zpsy24q9rux.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2511_zpsy24q9rux.jpg.html)

Here are the small end bushings (bronze) and the press tool and spacer used to ensure the bushing was inserted straight and with equal "stick-thru" on both sides.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2512_zpsbyqupxbm.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2512_zpsbyqupxbm.jpg.html)

Success ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2514_zpsap5r5icw.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2514_zpsap5r5icw.jpg.html)

Now they are done.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2515_zpsqz7iwra3.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2515_zpsqz7iwra3.jpg.html)

Then it was on to the wrist (gudgeon) pins and their pads.  The pads were made from "pop rivets".  Thought I'd try after reading about using them somewhere.  Don't know if I'd bother again; it may have taken the same time to turn up purpose-made ones.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2516_zpszsxucp0q.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2516_zpszsxucp0q.jpg.html)

While fiddling with little bits I figured I might as well get the (bronze) valve guides out of the way as well.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2517_zps6nt7liap.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2517_zps6nt7liap.jpg.html)

This is the beginning of the head bolts.  There ten of them with two being longer and double-waisted.  They are long relative to their diameter so I did the turning in stages and used a small centre throughout.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2519_zpssve2av2n.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2519_zpssve2av2n.jpg.html)

... about 1/2" at a time.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2520_zpsp0jzcybe.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2520_zpsp0jzcybe.jpg.html)

To get this ... this is a long bolt with an extra waisted section where the bolt goes through the siamese intake port.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2522_zpsd0fwzgyq.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2522_zpsd0fwzgyq.jpg.html)

Here are a couple of the shorter ones.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2529_zpskjh4bxfx.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2529_zpskjh4bxfx.jpg.html)

Once the end was trimmed to length and the socket head hole drilled to a couple thou over wrench size I could use my simple rotary broaching tool to cut the internal hex.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2531_zpsyh4tebhu.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2531_zpsyh4tebhu.jpg.html)

After all the new parts I went back to the cylinders and re-used a brass lapp from an earlier build to finish the cylinder bores.  Didn't realize until after uploading the picture that the camera focused on the near side instead of the bore ... oh well, you get the idea.  All cylinders ended up very close to each other (and print) and with a nice dull, smooth finish.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2532_zpsvyuloqz2.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2532_zpsvyuloqz2.jpg.html)

That's about it for this time.
Charlie


















Title: Re: 1/4 Scale Cirrus MkI
Post by: Dave Otto on July 02, 2016, 01:25:17 AM
Very nice work Charlie.

The rods turned out great; good to see progress on your engine.

Dave
Title: Re: 1/4 Scale Cirrus MkI
Post by: yogi on July 02, 2016, 01:47:39 AM
Fantastic work Charlie!  :ThumbsUp: :ThumbsUp: :ThumbsUp:
Thanks for the update.  :cheers:
Title: Re: 1/4 Scale Cirrus MkI
Post by: fumopuc on July 02, 2016, 06:33:29 AM
Hi Charlie, nice up date. Thanks for showing. Good to see your progress and the way to do it.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Steamer5 on July 02, 2016, 10:23:13 AM
Hi Charlie,
 Those are some very nice rods!

Looking forward to the next update, when ever life allows!

Cheers Kerrin
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on October 29, 2016, 03:59:00 PM
Time to update this build with the little bit of progress seen over the past months ... before I forget what I did and how.

I'd left off at the connecting rods but decided to carry on with the engine mounts for a change.  It was a chance to pay at small-scale fabrication.  I found some square tubing of an appropriate size "in stock" that was split to create some right angles.  Two angles were welded back-to-back to make the "webs" that bolt to the crankcase.  These were then drilled for the crankcase studs and cut to length.  Some solid round stock was drilled to clearance size and parted off to provide the vertical bits.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2533_zpsukpkqctf.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2533_zpsukpkqctf.jpg.html)

Then it was time for sorting out a way to hold these parts in alignment so they could be welded together.  Yes, this was an opportunity to play with a TIG welder ... I wasn't comfortable with silver soldering/brazing these parts together given the loads they'd be under.  Here is the fixture I came up with.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2534_zps2sftzjt5.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2534_zps2sftzjt5.jpg.html)

After a tidy-up, a bit of JB Weld and some primer I had some motor mounts.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2537_zpsotzrgnth.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2537_zpsotzrgnth.jpg.html)

Fortunately I'd put together a gadget from Home Shop Machinist (?) some years back that made (relatively) quick work of cutting the 16 #2-56 studs to length.  (This is one well used tool in a shop that does both aeromodeling and model engineering!)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2539_zpszghywowv.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2539_zpszghywowv.jpg.html)

... a bit of black paint and there you have it.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2540_zpsiw5r99il.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2540_zpsiw5r99il.jpg.html)

Then it was on to the pistons.  These were the last of the castings and mighty fine ones too - no pin-holes!  Here are three raw castings with one roughed to length and cleaned up inside.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2543_zpsxizoydje.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2543_zpsxizoydje.jpg.html)

A mandrel was made up to hold the pistons via a heat-shrink fit.  It was used to finish the pistons to length and near outside diameter.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2821_zpsvksfvbeg.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2821_zpsvksfvbeg.jpg.html)

Another fixture was made up to hold the pistons while drill the wrist pin holes.  It's just a block with a blind bore to match the pistons; cross-drilled to pin size.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2822_zpsj4dsuqtb.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2822_zpsj4dsuqtb.jpg.html)

Now I could re-purpose a piston holding fixture made up ages ago.  It only needed some bushes to size-up the "wrist pin" and a trim to match the piston inside diameter.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2542_zps4qemqwqc.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2542_zps4qemqwqc.jpg.html)

Here is a piston mounted on the fixture and cut to final diameter.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2823_zps8qllpmzw.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2823_zps8qllpmzw.jpg.html)

The piston ring grooves were cut with this setup.  Plan to use two compression and one oil control ring.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2824_zps97m2f58o.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2824_zps97m2f58o.jpg.html)

The batch ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2825_zpszyljruxi.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2825_zpszyljruxi.jpg.html)

Model Engine Builder magazine included an article about oil control rings a while back.  It illustrated a drilling jig for the piston oil control/drain holes that eliminated any chance for the drill bit to damage the grooves.  Here is my iteration ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2829_zpsmibwibib.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2829_zpsmibwibib.jpg.html)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2828_zpsttg34tyw.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2828_zpsttg34tyw.jpg.html)

... and the end result.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2831_zpsxmattvps.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2831_zpsxmattvps.jpg.html)

Here is a family photo including all the jigs/fixtures.  It seems to takes more parts to make parts than there are parts themselves!

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2833_zpso1nrdgud.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2833_zpso1nrdgud.jpg.html)

Next up were the piston rings - might as well stick to the theme!  The oil control ring is going to be grooved and then that groove cut through in 12 places with a tiny saw.  These blades are used for cutting electric motor commutators between segments.  This one is 3/8" in diameter and needed an arbour made for it.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2834_zpsmh0br9l0.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2834_zpsmh0br9l0.jpg.html)

Next the fixtures were made to hold the rings while being burnished to width, trimmed to outside diameter, grooved (oil rings) and the gap cut.  For this engine I'm going to use steel piston rings following (yet) another Model Engine Builder article.  They are made to free diameter and the gap cut.  No annealing required ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2835_zpsite8hfqs.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2835_zpsite8hfqs.jpg.html)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2836_zps1tnw22x2.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2836_zps1tnw22x2.jpg.html)

The piston ring "tube" was then machined from some "stress-proof" 1134.  It is bored to a calculated ID and turned to the free diameter (plus 10 thou for later finishing after parting off).

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2837_zpshtei3dij.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2837_zpshtei3dij.jpg.html)

Well my friends, that is about it for this time.  Now I just need to find a stretch of time to focus on parting off the ring blanks and carry-on finishing them.
Thanks for looking in ...
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: steamer on October 29, 2016, 04:26:20 PM
Nice!!!!


Great work!

Dave
Title: Re: 1/4 Scale Cirrus MkI
Post by: b.lindsey on October 29, 2016, 06:47:56 PM
Even though it  has been a while, you have made some fine progress Charlie!!

Bill
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on October 30, 2016, 05:30:24 PM
Thanks Bill and Dave!
Hopefully I can make a bit more headway as we move into autumn and winter.
Title: Re: 1/4 Scale Cirrus MkI
Post by: fumopuc on October 30, 2016, 11:43:18 PM
Hi Charlie, if I look out of my window, there are all the nice colours of autumn in the garden, so I hope to see some more progress of your beautiful engine soon.
Title: Re: 1/4 Scale Cirrus MkI
Post by: Zephyrin on October 31, 2016, 09:43:45 AM
Great work along this built, fabulous thread to follow, thanks !
The making of the tooling and jig at each step is very instructive, as I'm starting the built of a flat-headed inline 4, only the crankshaft made actually !
Title: Re: 1/4 Scale Cirrus MkI
Post by: Roger B on October 31, 2016, 10:01:24 AM
Good progress  :ThumbsUp:  :ThumbsUp: I like the jig for drilling the oil return holes. I will be following the manufacture of the oil control rings with interest  :wine1:
Title: Re: 1/4 Scale Cirrus MkI
Post by: gbritnell on October 31, 2016, 12:05:03 PM
You have some great machining ideas for making pistons. I'm still following along to see what the oil rings look like when finished.
gbritnell
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on November 22, 2016, 04:18:21 AM
Hi everyone, I finally made time to finish machining the rings for my Cirrus.  I started by doing the oil rings ... get the complicated ones over with first.  I faced off the "tube of rings" for a fresh start and then parted off 8 rings just a touch over thickness.  They were each then finished on a flat surface; figure-8's on some 220 grit for a close but free fit in the groove.  I did the same with the compression rings; 16 of them (can't have enough spares!).

Then the oil rings were put on the free inside diameter fixture in the lathe to cut the 0.018" groove on centre.  This was repeated for each ring.  The cutting tool was one previously ground from HSS and did the job without effort ... it was unnerving to watch but uneventful.

Once the oil rings were all grooved, the same fixture was put into a 3-jaw on a rotary table.  This table has been modified to be driven with a stepper motor and controller.  I could then program the controller to step around the perimeter to equally space the slits and take into account the gap to be cut later.  In other words, 12 slits were cut about 28 degrees apart.  The tiny saw mentioned in a previous post was used and it did a fabulous job start to finish.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2838_zpsntvgsixy.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2838_zpsntvgsixy.jpg.html)

Here is the end result ...

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2840_zpsqnjtgzu7.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2840_zpsqnjtgzu7.jpg.html)

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2839_zpsm0qouqnf.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2839_zpsm0qouqnf.jpg.html)

Then the rotary table was setup horizontally so the ring gap could be cut.  Once again the stepper drive capability made it easy to move a precise angle every time.  The same saw blade was used to cut the gap.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2842_zps2cibklsv.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2842_zps2cibklsv.jpg.html)

Next the other arbour was used to trim the outside diameter with the ring in a compressed state.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2843_zps8fxro9oc.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2843_zps8fxro9oc.jpg.html)

After fine adjustments to the gaps in a cylinder, we have 7 oil rings and 16 compression rings ... one oil ring got sacrificed to the shop gods (AKA machinist's screw-up).  I couldn't bring myself to cut the gap to final clearance (0.009") and trimmed each individually with a small file.

(http://i1196.photobucket.com/albums/aa405/cwelkie/Cirrus%20MkI/DSCN2844_zpsbwndokp7.jpg) (http://s1196.photobucket.com/user/cwelkie/media/Cirrus%20MkI/DSCN2844_zpsbwndokp7.jpg.html)

That's is for now.  Hopefully I can make more time for more parts soon - perhaps the valves should be next.
Cheers
Charlie






Title: Re: 1/4 Scale Cirrus MkI
Post by: Roger B on November 25, 2016, 09:13:09 AM
Those oil control rings are magnificent  :praise2:  :praise2:  :wine1:
Title: Re: 1/4 Scale Cirrus MkI
Post by: Jo on November 25, 2016, 11:17:48 AM
They are rather  8).

I really should do them for my 1/4 scale Cirrus and Gypsy :thinking:

Jo
Title: Re: 1/4 Scale Cirrus MkI
Post by: fumopuc on November 25, 2016, 09:07:04 PM
Hi Charlie, that's impressive.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on March 05, 2018, 02:57:08 AM
Well - it's been awhile.  In spite of the lack of updates I have been making some progress.  It's about time that I brought this topic up to date.

Since starting this build I'd wanted to grind the camshaft and considered numerous approaches to take and reviewed many grinder designs.  Given the amount of use I expected to receive I didn't want to over-invest in time and money.  The design used by (our own) Achim stuck in my mind as scalable in size and something I could build to work on my Clarkson T&C grinder.  One of the possibly unique things I did was 3D printing the cam template used.  The proof will be in the running but I think the cam turned out nicely.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on March 05, 2018, 03:04:59 AM
Another step forward came in the form of the spark plugs.  This model uses 1/4-32 size plugs and so were relatively straight forward.  I still needed to use my magnifying head gear though.  Corian was used for the insulators; 12L14 for the bodies and centre conductor; knurled brass for the lead retention nuts.  The bits were assembled with JB Weld as a sealant/adhesive with a swaged mechanical retention feature for extra security.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on March 05, 2018, 03:10:53 AM
As I started running out of parts to fabricate time came to begin assembly and final fitting.  It didn't take long before balancing things on 123 blocks became unsatisfactory so a display and running stand had to be designed and built.  I couldn't bring myself to use single vertical rods and wanted something a little more "girder-like" and frankly, more substantial for the anticipated running loads.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on March 05, 2018, 03:27:00 AM
Flash forward a number of shop hours and it's pretty much there from a fabrication perspective.  I plan to have the engine mount and tank stand powder coated for durability (and because I hate painting).  For the curious, I used Caswell blackening solution on the cylinder barrels, rocker arms/supports and crankcase breather bits.

Sadly I got into a groove whilst building the distributor and didn't take any photographs.  It contains a 4-magnet disc to trigger a hall-effect sensor with the usual rotor below the cap to distribute the spark.  Ignition timing is adjustable in sync with the throttle with mechanical linkage.

I've decided to build a universal ignition box for this project.  Previously I'd build a special system for each engine but finally realized that was ... wasteful.  The last photo shows the state of pay in this area so far.  The larger electronic board is the IGBT coil driver from Model Engine Builder magazine.  The smaller board will provide an electronic "buzz-box" input to the coil driver if desired.  (A switch will provide for selecting between single spark and multi-spark modes.)  There is room for an induction input tachometer and a volt/ammeter.  Power and point/hall-effect inputs will be via banana jacks.  H/V output will be through a 'safety' banana jack mounted in an additional insulator on the panel.

Sorry for the lack of updates ... hopefully better late than never.
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: michelko on March 05, 2018, 06:28:45 AM
Hi charlie,
Very impressive build :ThumbsUp:
I would like to ask what material you used for the rings? And how did you get them over the pistons?
I broke several oil rings, so i left them and run the bugatti without them.

Michael
Title: Re: 1/4 Scale Cirrus MkI
Post by: Roger B on March 05, 2018, 07:57:15 AM
Excellent  :praise2:  :praise2: Not long now until the first trials  :)

What material did you use for the distributor, Delrin?
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on March 05, 2018, 02:14:03 PM
Thanks Michael - I used 12L14 steel for the rings on this engine.  It was something I wanted to try for a change from cast iron.  I must admit to running this engine in for 30 or 40 minutes so far (electric drill drive while contemplating the next move) - it was "tighter" than any other so far.  On previous builds I've had luck expanding cast iron rings on a tapered mandrel to get them started onto the piston and then relying on fingernails to hold them open to get in the lower groove(s).  The large diameter end was slightly larger than the piston OD.  Managed to get all of them on a 9 cylinder Gnome without breaking any and they were cast iron.

Thanks Roger - Yes, it shouldn't be long now, especially when one considers how long ago the journey started.  If only winter would end ... snow banks in March are normally unheard of where I live!  Yes, I used Delrin for the distributor cap and rotor.  It's nice to turn and dimensionally stable enough for something like this.

Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: fumopuc on March 05, 2018, 06:01:46 PM
Hi Charlie, what a beauty.
Title: Re: 1/4 Scale Cirrus MkI
Post by: petertha on March 06, 2018, 08:09:34 PM
Looking great Charlie!
Re your 12l14 piston ring comment, are you heat setting them on a pin to a specific opening so they have radial tension once installed in the groove (the Trimble method I guess as its popularly known). Or is this a 'cold' process, turned & gapped?
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on March 06, 2018, 10:48:41 PM
Thank you Achim and Peter.

Peter - the piston rings were not annealed as provided for in the "Trimble method" for cast iron rings.  These were machined to an (oversize) outside diameter at the required width so a radial segment could be cut away providing the spring tension and hopefully the correct gap.  Any out-of-round is dealt with by holding the ring on a fixture in a compressed state for a final trim of the outside diameter.  If you look back to a previous post from November 22, 2016 you should see some photographs (if Photobucket hasn't killed access).  The whole process is done "cold"; one without the black art of heating/timing or non-magnetic ferrous phenomenon  :mischief:.

Cheers
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: michelko on March 07, 2018, 08:19:37 AM
Hi Charlie,
do you have experience with the combination of steel Rings and cylinders?
I made the Cylinders of my Bugatti Typ50 out of ETG100 This is a free turning high strength steel.
Compression Rings are made from GGG60 Iron. As mentioned before the oil controlrings broke on assembly.
So i am thinking of steel rings like you did.
Iam interessted in your ignition Setup. Can you tell me from what Issue of the modelenginebuilder magacine the System is?

Thanks in advance

Michael
Title: Re: 1/4 Scale Cirrus MkI
Post by: PJPickard on March 07, 2018, 12:06:37 PM
That thing is beeeyootiifuuull!
I'd love to build one of those someday, then I found out what the castings(if you can find them) cost!
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on March 07, 2018, 01:41:53 PM
Thanks PJ

Michael - No, I do not have any experience with steel rings.  I was curious about how they would work and the process of making them.  I'm led to believe that steel is used in many (most?) modern full size engines so why not try it here(?) ... that was my only rationale.

The ignition control board I'm using was detailed in Model Engine Builder, issue #34.  The article was by Dave Sage and John Gedde (with writing assistance from Mike Rehmus).  It inspired me to try an automotive "coil-over-plug" ignition coil.  The first bench test of the circuit startled me with the ferocious spark when triggered.  The rest of the "system" is just my attempt to build a universal ignition box for use on multiple engines, granted with more bells and whistles normally found in my usual rag-tag, last minute lash-up.  Once the rest of the components arrive on the slow boat from China (literally) perhaps I'll post some additional information on a separate thread.
Title: Re: 1/4 Scale Cirrus MkI
Post by: michelko on April 02, 2018, 08:50:57 AM
Flash forward a number of shop hours and it's pretty much there from a fabrication perspective.  I plan to have the engine mount and tank stand powder coated for durability (and because I hate painting).  For the curious, I used Caswell blackening solution on the cylinder barrels, rocker arms/supports and crankcase breather bits.

Sadly I got into a groove whilst building the distributor and didn't take any photographs.  It contains a 4-magnet disc to trigger a hall-effect sensor with the usual rotor below the cap to distribute the spark.  Ignition timing is adjustable in sync with the throttle with mechanical linkage.

I've decided to build a universal ignition box for this project.  Previously I'd build a special system for each engine but finally realized that was ... wasteful.  The last photo shows the state of pay in this area so far.  The larger electronic board is the IGBT coil driver from Model Engine Builder magazine.  The smaller board will provide an electronic "buzz-box" input to the coil driver if desired.  (A switch will provide for selecting between single spark and multi-spark modes.)  There is room for an induction input tachometer and a volt/ammeter.  Power and point/hall-effect inputs will be via banana jacks.  H/V output will be through a 'safety' banana jack mounted in an additional insulator on the panel.

Sorry for the lack of updates ... hopefully better late than never.
Charlie
Hi charlie
Could you post some pics of the distributor cap internals and rotor?
Thanks michael

I also build the ignition circuit. Works realy nice with an 12v automotive coil.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on April 05, 2018, 01:51:10 AM
Hi Michael - here are some photos as requested.

The rotor is a "hand" press fit onto a socket head cap screw that attaches the rotor shaft to the camshaft.  The knurling on the capscrew is used to hold, index and drive the rotor.  Under the rotor is the magnet disk and under that is the hall effect mount.

The hall effect mount started as an ring with an annular groove in it.  That was trimmed down and the left over piece was used to make the top cover.  The sensor is sandwiched between the top and bottom, inside the groove.

The hall effect is fastened to the bottom of the distributor housing which moves (i.e., rotates) with the mechanical linkage to the carb for timing changes with throttle setting.  The magnetic disk is held to the above mentioned rotor shaft with a couple setscrews to allow for setting the timing of hall effect activation.

The distributor cap leads run through holes from the top (for the spark plugs) and bottom (for the coil).  There are socket head cap screws that make contact with the wire end and pass through to the rotor on the inside of the cap.

Hope this all makes sense ...
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: Art K on April 05, 2018, 03:18:49 AM
Charlie,
The Cirrus is looking quite impressive. I like the distributor set up. I think the mechanical advance is a great idea. What sort of advance curve are you using?
Art.
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on April 05, 2018, 04:23:25 AM
Hi Art - thanks for the kind feedback.
I'm planning to start with 1 or 2 degrees BTDC at idle and adjust the linkage for 18 to 20 degrees BTDC at WOT (wide open throttle).  I'm not aiming for "wild and crazy" performance ... reckon it will run and I can fiddle with it from there.  Having variable timing was more about easier starting and limiting the likelihood of getting whacked by that wooden club :)
(It's a bit like putting a lawnmower on its side and then flipping the blade to start it!)
Charlie
Title: Re: 1/4 Scale Cirrus MkI
Post by: Art K on April 05, 2018, 12:01:38 PM
Quote
It's a bit like putting a lawnmower on its side and then flipping the blade to start it!
This reminds me of one of the log splitters that came up when Brian was building his. A flywheel with the wedge sticking out.
Art
Title: Re: 1/4 Scale Cirrus MkI
Post by: zeeprogrammer on April 05, 2018, 06:19:11 PM
Just finished going through the thread. Wow. That's a beautiful engine.
I learned a lot going through this...mainly how much I don't know and need to learn.  :Lol:
Title: Re: 1/4 Scale Cirrus MkI
Post by: cwelkie on April 06, 2018, 01:39:55 PM
Thanks Carl
I reckon your comment applies each and every one of us; "...mainly how much I don't know and need to learn.", regardless of what we think we know  ;D
Charlie