So here's the continuance of the update from yesterday evening......
While Daniel and the volunteers were knocking out other projects on the airplane during the day, I have pretty much been busy with the clerical end of my job. Paperwork, phone calls, tracking down parts, and so on. Ugh! That's certainly not what I look forward to doing all day. However, that
is why I get out here at 3 a.m. nearly every morning, so I can at least
try to get some actual work done. So yesterday, I more or less finished up the end cap for the lower portion of the tailgunner's compartment. Here's how it worked out..........
The first thing I had to do was to cut out the remaining portion of that old bashed up spinner and get it back into a basic shape that I could work with. So after cutting it out, I used the hammer and shot bag to bang the large dent out. It kind of makes it look like it went through a West Texas hail storm.........
After that, I just took it over to the English wheel to work out the dents from the hammer. It was important for me to use a light pinch on the dies so that I didn't actually stretch the metal out of shape. My only goal at this point in the process was to smooth it out.........
There, that's good enough for me to get started. There will be more wheeling later.........
The piece was much too large for me to even start with, so I just cut a couple of the corners off with the saw blade on the die grinder. One thing I don't think I've mentioned before is that when using the saw blade or even sanding discs on aluminum (particularly this rather soft aluminum), it is very important to keep it lubricated. I am using Boelube here, but when I run out, I'll probably just go get a bar of soap.........
Just like most of these "first steps" in this project, I had serious doubts that I'd ever be able to actually make it all work out after clamping the piece on for the first time. You can see that you have to use your imagination to even catch a glimpse of what you want the finished product to look like.........
So after trying to work out in my head how I'm gonna make this work, I pressed on. The Sharpie marks you see in this photo (viewed looking inside the fairing) are only there for a general reference. The outer line is obviously a rough sketch of what will be the edge of the material, while the circles in the center tell me the areas that will need to be stretched the most in order for that edge to end up meeting the other peice of the fairing.........
Once the piece is marked, I go to the shot bag and English wheel. There is a lot of back and forth, back and forth during this step. It's much easier to go back and stretch the material more than it is to start over because you've stretched too far.........
You can see how it slowly came into position, as compared to when I first marked it........
Once I was happy with the general fit, I wiped off all of my previous marks and re-marked the edge. I then went over to my Beverly Shear and cut off the excess material. I used this shear vs. the saw blade at this point so that I could have more control over what was cut. This will end up being the final cut before final trimming and welding, so attention to detail here is important........
One last check of the fit before welding it all together (by the way it fits better than it looks in this picture, as the only thing holding it up were two clecos at the top, so it tilted a bit before the photo was taken).........
I then clamped the two pieces together and cleaned the edges thoroughly before welding........
I had to tack it all together first........
Then I welded it up all the way around. I discovered that I had cracked some of the weld on the original piece I built when I used the English wheel to work out some low spots earlier, so I went ahead and rewelded that all the way down while I was at it to insure it wouldn't happen again........
Now that it's all one piece, I needed to knock off the high spots of the welds so that I could then tap out the rises and depressions from the heat transfer when welding. I just used a hammer and dolly for the basic shaping........
And once I got the basic shaping done with the hammer and dolly, I walked back over to the wheel (with a light pinch) to get everything kind of back to a uniform shape......
And sure enough, after sanding the welds down and taking care of some other imperfections with the wheel, it turned out at least somewhat like I was looking for.......
There are going to be two formation lights that go in the end of this fairing, but I'm going to wait on putting them on until after I build the door tracks and doors for this position. I just want to make sure I get everything lined up juuuuuust right and don't want to ruin this piece by cutting the holes for the lights in the wrong spot.
Even though the fabrication of this piece is more or less done, I'm still not completely happy with how it turned out. Sure, it'll work, but if I end up having a little more time as this project moves forward, I may try to make it look a little better. Right now, it looks like someone took an old, junk spinner and made the fairing, rather than stamping it out on a press. I'm wanting the stamped out on a press look.
Gary
Login
Register
FAQ
Search
P.S. Love the pictures of the presses! United has a drop forge to make the lip for Jet engine inlet cowls and I'm told they used the same machine in the 40's to make cowling repair filler parts for B-17s.
