6/8/2010

Paint Testing and the Tale of the Tape

Wow has it been ages since an update. I have been making progress, but I'll concede it has been slower that time's past. My wife has left the professional work world and has decided to return to school...law school at that. She's through 2 years now, with 1 year left to go. So... that has translated to slower progress in the shop, as I'm the main guy keeping the family going and keeping a watchful eye on our 2 young boys.

But there is still progress, and first up in this update is some legwork in prepping for paint. Since the last update the entire 2nd bird, the 'show plane,' is almost complete, and a ton of time has been spent doing prep body work, getting ready for paint. During the process of making the 2nd bird, a few parts did not come out the way I liked and were scrap. I tried some new techniques to make them lighter. Some worked, and some did not, but I did learn a lot.

So, now armed with some junk parts, I set about getting the paint just right. You'd think black would not be that hard, but.... You'll see below a few shots showing different shades of black, and also a very special piece of metal in the photos. After much digging and calling, and a few dollars changing hands you'll see I've gotten my hands on an actual piece of titanium, that has the original black paint on it, from a real SR-71 Blackbird. This piece has even flown at altitude, speed and temperature, so the shade is just right. The real paint actually cures in flight and the plane lands after being freshly painted a slightly different shade than when it goes up. This is why it is very difficult for a museum to reproduce a missing part and get the look just right.

You'll also notice I'm working on getting the 'flat' part of the clear just right too. I've learned that a good technique is to do a proper flat clear, then 'chalk' the surface, with a big fuzzy brush and some artist chalks that are lighter gray. It is very surprising how well the chalk stays on the surface. If it were gloss paint, it would wipe right off, but not on the flat. It seems to get a good foot hold on the rough surface and stay put, even if you wipe your hand across it. I can remove it if I really soak it with a cleaner and rub hard, but for normal use, it looks like it will work just fine, and gives it a really good look.

Lastly, take a look real close, and you see some tests on different rivet looks. I am going to settle on using some extra thick rivets from Aeroloft, that go under the paint. They give it a nice little bump, that catches the chalk, and when rubbed away, give it a great look, that is very realistic

And now for the tale of woe. After working double time for the last 18 months, shooting for trying out for the US team for the Jet World Masters, I have some bad news. On this second show plane, I made each and every part significantly lighter, knowing weight would be an issue. I had a very big hill to climb to shave enough weight off....actually a 20 pound hill. Of that 20 pounds to shave off the prototype weight, I was able to lighten it by 15 pounds. I knew those last 5 pounds were going to be tough. They have proven to be quite elusive and it's looking like the finished bird will be around 5 pounds over the weight limit to compete. As much as it stinks, I'll still be left with a good looking plane that flies great, and will be around 15 pounds lighter than the prototype flew at. Jerry also made a great observation, that it was never part of the design goals to be able to make competition weight. It was an extra thing I tossed on there at the 11th hour when we heard the Jet World Masters was coming to the US in 2011.

You can see below, the board in the shop that I've been keeping track for the last 18 months, every last part along the way. Each part was weighed down to fractions of an ounce, as I focused on keeping weight to a minimum, but yet keep the airframe safe. Another upside is that now I've got some room (weight wise) to put some extra goodies on, such as lighting and a decked out cockpit, and drag chute. The prototype weighed 72 lb. fueled, with no paint and no goodies, so a 2nd bird needed to be build in any case, to keep under the 75 lb. limit anyhow.

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