Showing posts with label Page 23-06. Show all posts
Showing posts with label Page 23-06. Show all posts

Wednesday, September 22, 2010

My 1st Anniversary

October 14th was the one year anniversary of my first actual work on the building of N284DG. And I missed it.

Typical man.

I made up for it tonight by finally finishing page 23-06. It took eighteen days, and note that page 23-06 does not include the bending of the longerons, but did include the painting of the interior. And, truth be told, a whole lot of those eighteen days were days when I didn't even go out to the hangar, much less work on the airplane. And yes, a few of them were spent correcting mistakes. Still... eighteen days, one page.

As I mentioned, those eighteen days of off and on labor culminated in finally having both fuselage side skins riveted on. The right side skin went on a couple of nights ago when I was able to farm out some of the work to the effervescent and ever-vacillating Jack the Sailor, a prospective RV-12 builder that is currently in the "can I really do this" and "do I really want to" phases and has been for weeks. Been there, done that. I figured pulling a few rivets would help convince him that anyone can build one of these things, but he's sharper than that. He quickly realized that the riveting is the east part; the hard part is getting all of the pieces prepared and assemble prior to riveting. Still, he got some good experience and that can only help with his decision making.

I started him out by having him install ten nutplates. Sure, I know what you're thinking, and you're right. I am sick and tired of installing nutplates and I was more than happy to foist off that job, but pragmatism rises to make my defense: if you can't install nutplates, you ain't building an RV. It was a good exercise. It helped that I had everything pre-dimpled and all Jack had to do was cleco and rivet, but those are fundamental skills and you have to start somewhere.


He only decapitated two out of twenty of those daggone irritating mandrels, which beats my best record of three out of twenty. Those don't bother me as much as they used to now that I know I can just tap them through with a hammer rather than cut them off and file down the stub.

While Jack was doing that, I busied myself with hanging the other side skin on and prepping it with don't-rivet-here clecos.

This was the second try with these three. I originally had the line of clecos starting in the set of three holes further forward. I was doing the right side skin, but the left side is the one shown in the drawing. I think from now on I will work on the side that is depicted in the manual and then transpose to the other side. Less mistakes that way, I would imagine.






As we all know, I am by my very nature a supremely generous individual, so it should come as no surprise that I let Jack do the majority of the riveting. I like to think that anyone would have been as charitable in this situation, but probably not. I'm a saint among men, I am.


While Jack was riveting, I happened to notice this little tab under the longeron. That's the one on the left - I checked it because I felt springy resistance when clecoing that hole on the right side. I recognize that feeling as a tab that is being pushed down by a cleco. It was. I fixed the alignment on the right side and checked to make sure the left was okay too. It was.


Jack's out of town now so I had to was lucky enough to be able to rivet on the left side skin by myself tonight. It sure takes a lot longer to do alone!

And that's the end of page 23-06!

Saturday, September 4, 2010

Wikipedia, wrong again

Wikipedia continues to disappoint. The most recent example of an incorrect entry is on the topic of "what is the densest element?"  Here's their answer:
"The measured density of [iridium] is only slightly lower than that of osmium, which is often listed as the most dense element known. However, calculations of density from the space lattice may produce more reliable data for these elements than actual measurements and give a density of 22650 kg/m³ for iridium versus 22610 kg/m³ for osmium. Definitive selection between the two is therefore not possible at this time."
"So," you ask, "how can you so definitively say that such a non-definitive answer is wrong?"

Simple. Because the correct answer is neither of those. The correct answer is.... well, I'll get to that.

First, I had to cut the second spar slot in the right side skin.







As you may infer from the fact that I'm wearing a sweatshirt, our heat wave has been replaced with unseasonably cold weather. Ohio weather is at best a study of extremes, best studied from more temperate states.

I used the nibbler again, and while I think it makes a cleaner cut than shears, it does present the down side of being somewhat difficult to hold on a completely straight cut. You won't have any trouble choosing the side that I cut versus the side that Van's cut.


I was wrong when I said that it was a waste of time to cleco the left skin onto the fuse. It turns out that the little gusset that needs to be riveted on is accessible even with the skin in place.


 My prediction regarding impending match drilling was proved correct pretty quickly. I thought this picture in the build manual was odd, though. That hatched part in the circle gets cut off once the longerons are drilled. I didn't think it was odd to have a piece on there that would later get removed; every now and then there is a tab that must be used to hold the part in whatever machine Van's uses to manufacture parts. I just thought it was odd that they had bothered to drill holes in it.


I can live with "odd" in the short term - I just move on with the stuff that isn't odd.

The skin gets clamped to the longeron. That's not odd at all.


Then drilled.


Each hole is clecoed as soon as it's drilled to hold the skin flat.


I didn't see any reason to drill for a part that's going to get cut off anyway.


Then, the next side. As I was drilling my way down the side, I noticed something wrong on the roll bar support plate:


The hole was marked for countersinking, but no countersinking had been done! I figured I'd finish drilling the longeron row and then fix the countersinking mistake. I eventually got to the end, where yet again I was confronted with the inexplicably over-engineered throw-away part. I mean really, why have us drill holes through a part that's just going to get cut off and thrown away? Then it struck me, and I have to confess that the simplicity of the answer embarrassed me: to put holes in the longeron for the tail cone to rivet into. The part of the skin that gets discarded acts as a drilling template.

So now you can see why I believe that neither iridium nor osmium is the densest element on Earth.

It's because I am.


Once all of the longeron holes were drilled, I went back to countersink the hole on the roll bar support.


For some reason I couldn't get the countersink bit to dig deep enough into the hole. After a couple of adjustments to the bit cage didn't help, I thought that maybe something was obstructing the part of the bit that goes through the hole. Well, I was right, in a way.

I hadn't match drilled those holes yet.

See? Iridium ain't got nothing on me when it comes to dense.