As a recovering Quick Builder working on an RV-3, one of the things that I find to be the most fun and the most challenging is that there are very few ?clues? to whether or not you are getting all of the details right. In a quick build kit ? or a pre-punched slow-build ? one of the best clues that you have missed something is an empty hole. There shouldn?t be empty holes (unless they are simply tooling holes) ? every hole should have a rivet or fastener of some kind. So when the big parts look done, you can sit and stare at your project, looking for empty holes, and those are clues about what work you have left to do.
But with an old fashioned kit such as a -3,-4, or -6, you don?t have those same clues leading you to more work. You have to have, or build, and understanding of what it takes to make an aluminum aircraft structure work. The old standby, AC43.13, is a great place to get a million details on rivet spacing, repairs, edge distances, etc?.but it doesn?t really tell you how things work, unless you look at it with a critical eye. In actuality, I find the greatest asset we have in building the -3 are the two already-finished RV?s sitting in the hangar with the project. You see, most of the RV?s are essentially the same 9the -10 and -12 excluded) when it comes to their basic structural design. The sizes and shapes are different of course, but the ?big picture? remains the same. I was looking, for instance, at how the bottom cockpit skins overlap on to the long lower tail cone skin, and sure enough ? the -6 is a close enough example to give me a clue what is intended. Drawings? Well, yes, we have drawings?.but for the -3, they leave a great deal to the imagination. My hats are off to those that built a -3 as their first project! Without the experience of working on the newer models, this would be challenging indeed.
Where this rambling leads is what I call the ?Laying on of the Eyes? ? something that Louise is learning by watching. Quite frankly, it involves sitting and looking at the project, quietly, and with my hands in my pockets. I study the lines of clecos and rivet holes already done, and look for gaps. The seat rib area is a great example. Five ribs, a cross-member, and a forward and aft bulkhead, all coming together in a maze of intersections. The plans give some general guidance on rivet size and spacing, then leave you to your own imagination. Rivets on the forward and aft flanges? I suppose they would be nice to rigidize the structure ? even though they are not shown on the plans! How about those little quarter-circle ribs that go on the back of the F-305 bulkhead and transition the lower fuselage from a rectangular shape to a semi-circle?well, fasten them on there some way?whatever makes sense.
I like to sit on a stool and let my eyes roam from nose to tail, looking for these little details. I can log many hours of work with only a few holes drilled or clecos installed ? it takes time to find the missing bits. It really helps to have another experienced builder staring along with you (we all know the value of this when it comes to finishing and final assembly) but it can take a long time for a new person looking at a project to get in tune with just where it is. There is (I hate to say it), a Zen-like quality about this gazing ? we tune in to what the structure needs, and where it is missing a link. After a while, you can see the loads being transferred from the wings to the fuselage, the engine to the wings, the fuselage to the tail. You can see where it needs to be stiff, and where it can flex. Understanding the structure is one of the most enjoyable things about building for me in fact ? it sure beats thinking about all of the dimpling and riveting yet to come.
I imagine that the Laying on of Eyes will continue until well after we roll the canoe, probably until the wings are on. From that point on, the rules of finishing begin to apply. Until then, I will sit on the stool and stare at the structure, learning its secrets as the parts box empties and a fuselage grows seemingly from nothing?.
Paul
But with an old fashioned kit such as a -3,-4, or -6, you don?t have those same clues leading you to more work. You have to have, or build, and understanding of what it takes to make an aluminum aircraft structure work. The old standby, AC43.13, is a great place to get a million details on rivet spacing, repairs, edge distances, etc?.but it doesn?t really tell you how things work, unless you look at it with a critical eye. In actuality, I find the greatest asset we have in building the -3 are the two already-finished RV?s sitting in the hangar with the project. You see, most of the RV?s are essentially the same 9the -10 and -12 excluded) when it comes to their basic structural design. The sizes and shapes are different of course, but the ?big picture? remains the same. I was looking, for instance, at how the bottom cockpit skins overlap on to the long lower tail cone skin, and sure enough ? the -6 is a close enough example to give me a clue what is intended. Drawings? Well, yes, we have drawings?.but for the -3, they leave a great deal to the imagination. My hats are off to those that built a -3 as their first project! Without the experience of working on the newer models, this would be challenging indeed.
Where this rambling leads is what I call the ?Laying on of the Eyes? ? something that Louise is learning by watching. Quite frankly, it involves sitting and looking at the project, quietly, and with my hands in my pockets. I study the lines of clecos and rivet holes already done, and look for gaps. The seat rib area is a great example. Five ribs, a cross-member, and a forward and aft bulkhead, all coming together in a maze of intersections. The plans give some general guidance on rivet size and spacing, then leave you to your own imagination. Rivets on the forward and aft flanges? I suppose they would be nice to rigidize the structure ? even though they are not shown on the plans! How about those little quarter-circle ribs that go on the back of the F-305 bulkhead and transition the lower fuselage from a rectangular shape to a semi-circle?well, fasten them on there some way?whatever makes sense.
I like to sit on a stool and let my eyes roam from nose to tail, looking for these little details. I can log many hours of work with only a few holes drilled or clecos installed ? it takes time to find the missing bits. It really helps to have another experienced builder staring along with you (we all know the value of this when it comes to finishing and final assembly) but it can take a long time for a new person looking at a project to get in tune with just where it is. There is (I hate to say it), a Zen-like quality about this gazing ? we tune in to what the structure needs, and where it is missing a link. After a while, you can see the loads being transferred from the wings to the fuselage, the engine to the wings, the fuselage to the tail. You can see where it needs to be stiff, and where it can flex. Understanding the structure is one of the most enjoyable things about building for me in fact ? it sure beats thinking about all of the dimpling and riveting yet to come.
I imagine that the Laying on of Eyes will continue until well after we roll the canoe, probably until the wings are on. From that point on, the rules of finishing begin to apply. Until then, I will sit on the stool and stare at the structure, learning its secrets as the parts box empties and a fuselage grows seemingly from nothing?.
Paul
