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CriCri MC-15 in San Francisco

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michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
A long overdue update

It’s been well over a year since my last update, so here it goes.

Even though I haven’t been great about keeping my blog up to date my build hasn’t been entirely idle either. Life did get in the way for some stretches but I still managed to keep working on it here and there. Here are the things I’ve been up to:

Turning the flap tube ends 601-30 on the lathe with some cleanup on the mill.

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Cutting various 4130 steel parts on the band saw and cleaning them up with the disc sander and file. I was plotting out the cad files I made from the plans and using a glue stick to glue them to the sheet stock to get the proper dimensions. I didn’t notice my printer had scaled some of them so I had to redo. Check your settings to print at 100%! :)

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Continued in next post...
 

michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
Purchasing the canopy bubble from Wayne Butt from New Zealand. He had a couple extra from his own build a few years ago and had offered them for sale. This was great, as I had no idea as of yet where to get the canopy from. But boy, having to deal with the US port authorities to get it cleared through customs was an experience I would’ve loved to avoid. Multiple trips to the customs offices, a small folder full of paperwork and some fees later I could finally pick it up from the airport where it had been waiting for a couple weeks.

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Building the fuselage cradles. If these look familiar it’s because you’ve seen them in Shannons build blog over on homebuiltaircraft.com. He has a lot of great ideas and I’m always glad if I can learn from his experiences. Like Shannon I made the convex cradles in addition to the concave ones in order to be able to conterdrill the fuselage angles to the already predrilled fuselage panels.

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Cutting and forming the fuselage angles. Borrowed from another one of Shannons ideas I used the CNC to cut my corner angles to their proper width by cutting a slot in a MDF board first and then lodging in two angles at a time. Some cleanup with file and sandpaper and they were good to go! I built a tool similar to the one described in the manuals to form them to fit the contours of the fuselage. It works by drawing the angle through and pushing on them at the same time to get the bend. A little fine-tuning with the mallet and I got them fitted pretty well.

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Continued in next post...
 

michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
Starting to fold parts for the fuselage frames. I am cleaning up all my CNC-cut parts with file and sandpaper to smooth out all the tool marks. For all the smaller pieces I had purchased a small bench brake. Surprisingly my bend calculations I had made when creating the CAD files proved pretty accurate and most of the parts came out within a couple tens of millimeters. It’s such a pleasure to see the parts coming together perfectly with the matching predrilled holes. The pins are another one of Shannons ideas, simply some 1/16″ welding rod that was bent to form the pins. This serves to hold together and align the pieces temporarily until I decide to match drill some of the holes to final size and cleco the parts. I had also cut some templates for the frames out of 1/8″ MDF to double check my frames. This seems to have been mostly unnecessary as the frames with the CNC drilled holes are very accurate.

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Making former blocks and forming some of the 0.5mm and 1mm parts. MDF cuts easily on the CNC but is a little soft so I used some sanding sealer to harden up the edges. With a mallet the aluminum bends cleanly and without wobbles if done progressively.

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Continued in next post...
 

michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
Preparing the caps for frame 4. I cut the 1/16″ angles to the correct width on the CNC, the same way as with the corner fuselage angles. Then I used a bandsaw to cut out the notches at the ends and cleaned them up with a file and sandpaper.

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Hoping to post some updates more regularly from now on! :)
 

michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
Today I temporarily assembled frame 4 with the help of various clamps and pins. Nothing drilled to size or glued yet, but I was happy to see that it went together really well and turned out very precise too. I think there is the odd hole or two that doesn't quite line up so I'll have to see whether I have to redo the parts or if it'll still work when I drill the holes to size.

I also started to counter drill the fuselage angles to the pre drilled fuselage panels using the convex cradles that I had built for this purpose.

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michael

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Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
Thanks! :)
Yes, I won't glue or rivet F4 until I have the spars made. But I appreciate the reminder! :)

Today I continued counter drilling the rest of the fuselage corner angles. This was some sort of milestone for me because I could actually start temporarily pinning parts of the fuselage together. It's incredibly satisfying to see the fuselage come together after months and months of working on individual parts (and previously not having the space to assemble anything). It's starting to look like an actual airplane project! :)

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michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA

michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
Progress has been slow the last couple months, life events (weddings etc. ;) got in the way.

Recently I cut out the folding jig for the cockpit borders 201-09 out of mdf as well as the actual parts from 0.5mm 2024. Even though I had cut them already I decided to make new ones from the file Shannon is providing on homebuiltairplanes.com which offer a better fit.

I folded the parts progressively with a mallet. At first I was a little worried of how wavy the aluminum got, but after taking it out of the jig it curved the other way and straightened itself out. I still have to do a few minor adjustments to the curvature but overall it's fitting pretty well. I'm also planning on cutting a strip of aluminum with the drill holes as a template to drill the borders and the corner angles.

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etard

Well-Known Member
Joined
Dec 22, 2014
Messages
118
Location
Banning, CA
Nevermind the airplane, check out that workbench top!!

This will be an epic build, thanks for sharing it here and keep up the good work!
 

michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
It looks like this thread has been sorely neglected over the last year. There hasn't been a whole lot of progress but here it goes.


I folded/formed some more of the front fuselage parts:


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The fuselage corner angles needed a second pass of shaping to make them match the curvature of the 'cradles' perfectly. I also made the cut-outs at F4 and shaped the ends properly.

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michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
These are the stiffeners for the wing spars. I had cut these earlier, but I just now got around to folding them. My little bench top folder made short work of this.

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More fuselage parts formed:

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I also made my first attempt at forming the cockpit borders. They came out ok after adding a few flutes, but I might try to recut and form them again to get them perfect.

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michael

Active Member
Joined
Jan 18, 2011
Messages
25
Location
San Francisco, CA
This was my second attempt at making the cockpit latches. I had made form blocks out of aluminum for these. They are tricky because the bend radii are so small and 2024 cracks easily. Most came out passable, but I will probably redo a couple of the parts that have an indication of cracks.

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The front part of the upper fuselage needs a complex fold, that varies in angle. I made a former out of MDF but I must have underestimated the spring back and the angle is a little too shallow on the part. I might end up having to recut the former with a steeper angle.

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The elevator pivots proved to be most complicated parts for me so far. I'm not a learned machinist so it took multiple tries (and end mills :( ) to get them programmed and machined correctly. They did come out beautifully though in the end. I only machined the holes to 13.7mm, so I still have to ream the holes to exactly 14mm for the ball bearings.

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Similarly challenging is the pushrod attach fitting, although I had learned a lot from making the pivots, so this one went better.

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Currently I'm mostly working on getting all the parts for the horizontal tail done so I can start its assembly. I'm hoping for this to be my first finished part of the plane. It's what Michel Colomban recommends to start with as it requires a lot of the techniques that are needed throughout the build and it'll hopefully be a moral booster for me to have a finished part.
 

sotaro

Well-Known Member
Joined
Feb 26, 2011
Messages
140
Location
San Francisco
Michael,
A Cri Cri in San Francisco. A better plane for the small spaces available here I cannot imagine.
I live here too and would love to see your project. Any chance of that? I will be glad to buy the coffee.
 

Victor Bravo

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Joined
Jul 30, 2014
Messages
7,892
Location
KWHP, Los Angeles CA, USA
Looking at the earlier posts... why did you choose such a slow feed rate for the CNC cutter in thin aluminum? 0.5 inches per minute seems agonizingly slow?

Congratulations on a beautiful project, and thank you for posting the photos/progress reports.

What engines are you thinking of using?
 
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