Saturday, November 7, 2009

After the Flettner Tab? An unscheduled break.

I re-riveted the control horn on the left side of the Flettner tab and now the two halves fit together like two slices of Oscar Mayer 98% Fat Free Sliced Beef Bologna, if you'll forgive the uncompensated product placement simile. Times are tough (but Oscar Mayer 98% Fat Free Sliced Beef Bologna isn't!) and Schmetterling is always on the watch for new revenue stream opportunities! Here's hoping that the wonderful and caring marketing folks at Oscar Mayer see the enormous opportunities here.

I'm glad (and yes, somewhat proud of myself) for going back and fixing the left side. Even if it had fit on the airplane, it would have been one of those things that, once I was aware of it, would always catch my eye and act as an eternal badge of shame. But now? I'm thrilled with how nice it looks:

Allow me, if you will, to segue onto another subject. I discovered the flaw in the control horn attachment because I was able to leverage our modern internet-based communication opportunities to learn from others that have built before me. Had I not been researching ahead by reading other build logs, I would not have known to be hyper critical about the spacing of that control horn. In the grand scheme, this was a minor fix to a minor problem. But as I was reading ahead and preparing to start on section 9 (the horizontal stabilator), I came across a much more serious issue that I would have gotten wrong, and this one would have cost some me some money. Money unlikely to be recouped from my as yet to be realized revenue from the good folks at Oscar Mayer.

The first step in the building of the HS is a load of countersinking. Nothing new there, right? Here's the excerpt from the plans:

Note "MACHINE CSK, CS4-4" and "MACHINE CSK, AN426AD3" and tell be what you'd do. Well, you'd have done what I would have done, which is to grab your countersink bits and countersunk the holes. You simultaneously would have ruined both of your HS-1211 spars. Why? Good question! You would have ruined those parts because the CS4-4 rivets require a 120 degree countersink, not the standard 100 degree countersink. Somewhere (but not in the plans, as far as I can tell) there will be a small-font, completely obscure chart that tells you this. I contend that a far better approach, particularly in the case of the anyone-can-build-it RV-12, would have been to spend the $.000001 in toner required to print "WITH 120 DEGREE CS BIT" on the page.

I included the rivets in the picture so you can see the difference in the angles. It's very, very subtle. If Van's is counting on builders like myself noticing that kind of disparity and wondering if perhaps, just maybe, we might need a different countersink bit, well, I don't see it happening.

So, disaster was narrowly averted, but now I have to wait until the 120 bit arrives via FedEx Geriatric Turtle non-express (why am I so cheap on the shipping? Hey, ask Oscar Mayer!) some time next week. As long as I was getting hooked for $7.95 shipping on a tool that weighs less than an ounce, I went ahead and ordered another specialty tool that my newfound practice of reading ahead indicates I will need within a couple of weeks.

For now I will get the Flettner pieces final riveted and look ahead in the HS plans to see what needs to be deburred and/or fluted. The HS is a pretty big chunk O' airplane, so there's bound to be at least three or four days worth of that kind of stuff.


Jim T said...

Thanks for the info about the 120 degree bit. I remembered this post when I was going over my plans and made a notation on them regarding this.

Kevin said...

Nearly three years after your excellent suggestion Van's still hasn't spent the $.000001 in toner to include "WITH 120 DEGREE CS BIT" in the plans sheet. I couldn't find it anywhere either. WTH?

My thanks also for the post. It was a close call but Schmetterling saved my butt again.

RV kit # 120-666 "The number of the beast"

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