Hi;
This is similar to a question I asked some time ago, but different enough to start a new thread, methinks. My question(s) are about types of rivets on the leading edge areas of wings, as would be used on a Titan-like homebuilt, with the same performance, weight, engine, etc.
The Titan51 replica Mustang has CNC-formed foam blocks inside the leading edge of the wings. The leading edge skin is glued to this foam. No rivets. Then, the section aft of the spar has skins that are pull-riveted to the ribs. I assume that they do this to keep drag on the leading edge to a minimum. I also assume that the rivets are low-profile Avex rivets, or something close to this. The foil is Harry Ribblett's 35-415, and thickness tapers down a bit toward the tip.
So I'm looking for feedback on the following:
I would use the same airfoil, and omit the CNC foam block from the leading edge. I would use normal ribs and rivets in the leading edge. If I were to use flush rivets, probably the solid bucked type, for the top of the wing surface (leading edge) and low-profile Avex rivets for the bottom surface of the LE, would this be a serious concern? Let's assume that I'd use enough rivets for structural requirements. I guess what I'm asking, is it better to keep the top of the leading edge smooth, rather than the bottom, assuming that it's even important?
Avex, low-profile pull rivets would be used from the spar aft.
Am I being overly concerned about the top surface remaining smooth? Is the onset of the stall more likley with a zillion little rivet bumps on the top of the leading edge, as compared to a nice smooth surface? I don't know how stall-sensitive this airfoil is. (or any airfoil for that matter).
Last, bucked rivets are a concern for me. I have no doubt that I could learn to install them, but it usually needs 2 people, and makes a major racket that annoys family and neighbours. I would stick with pulled rivets everywhere, including leading edges, if I were convinced that there were no aerodynamic penalties.
And for cost reasons, Cherry Max rivets, at a dollar each, are not a reasonable option. They would have to be the pulled type, Avex or similar. I don't know all of the head profiles that I can get these rivets in, but the lower profile, the better. I would also like to keep the amount of work down to a reasonable level, and since I have never dimpled skin to accept countersunk rivets, this may be a time-consuming task. Anyone dimpled a whole leading edge to keep their surfaces smooth? Is it a royal pain?
Thoughts are most welcomed, and thank you. Tom.
This is similar to a question I asked some time ago, but different enough to start a new thread, methinks. My question(s) are about types of rivets on the leading edge areas of wings, as would be used on a Titan-like homebuilt, with the same performance, weight, engine, etc.
The Titan51 replica Mustang has CNC-formed foam blocks inside the leading edge of the wings. The leading edge skin is glued to this foam. No rivets. Then, the section aft of the spar has skins that are pull-riveted to the ribs. I assume that they do this to keep drag on the leading edge to a minimum. I also assume that the rivets are low-profile Avex rivets, or something close to this. The foil is Harry Ribblett's 35-415, and thickness tapers down a bit toward the tip.
So I'm looking for feedback on the following:
I would use the same airfoil, and omit the CNC foam block from the leading edge. I would use normal ribs and rivets in the leading edge. If I were to use flush rivets, probably the solid bucked type, for the top of the wing surface (leading edge) and low-profile Avex rivets for the bottom surface of the LE, would this be a serious concern? Let's assume that I'd use enough rivets for structural requirements. I guess what I'm asking, is it better to keep the top of the leading edge smooth, rather than the bottom, assuming that it's even important?
Avex, low-profile pull rivets would be used from the spar aft.
Am I being overly concerned about the top surface remaining smooth? Is the onset of the stall more likley with a zillion little rivet bumps on the top of the leading edge, as compared to a nice smooth surface? I don't know how stall-sensitive this airfoil is. (or any airfoil for that matter).
Last, bucked rivets are a concern for me. I have no doubt that I could learn to install them, but it usually needs 2 people, and makes a major racket that annoys family and neighbours. I would stick with pulled rivets everywhere, including leading edges, if I were convinced that there were no aerodynamic penalties.
And for cost reasons, Cherry Max rivets, at a dollar each, are not a reasonable option. They would have to be the pulled type, Avex or similar. I don't know all of the head profiles that I can get these rivets in, but the lower profile, the better. I would also like to keep the amount of work down to a reasonable level, and since I have never dimpled skin to accept countersunk rivets, this may be a time-consuming task. Anyone dimpled a whole leading edge to keep their surfaces smooth? Is it a royal pain?
Thoughts are most welcomed, and thank you. Tom.
