CA hinge questions
#1
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CA hinge questions
1. How much balsa material should I have to slide my hinge into? Example: I have 1" long CA hinges. If the leading edge of my built-up aileron and the trailing edge of my wing are both made of 1/4" thick balsa, then a significant portion of the CA hinge will remain unused, sticking out of the end of the material inside the wing and aileron. Is this okay?
If the answer to number one is "No, that's not okay", then I either have to use thicker balsa in the wing and aileron, or I have to apply some kind of balsa hinge blocks to thicken the material in the hinge area. Using thicker balsa is heavier, and that's bad. But I can forsee a problem with hinge blocks, too- if I use CA glue to apply hinge blocks, than certainly some of the balsa grain will absorb the CA glue and therefore no longer be available to wick the CA from the hinges when they are installed at a later point. 2. Is this a valid point, or am I overthinking it?
(I thought for certain these would be frequently asked questions, but I can't find what I'm looking for searching the archives.)
#2
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RE: CA hinge questions
Well, your example sort of confuses the deal......
CA hinges aren't exactly the most free hinges. So you wouldn't want to use large CA hinges if your TE and aileron widths were really 1/4". Because the structure wouldn't be very strong and the hinges probably be too stiff for whatever servos were in such a light structure. You'd really need to find the very thin and small CA hinges and they probably still would be somewhat stiff for any somewhat delicate structure.
But don't worry about adding structure to cover all the hinge, because the rest wouldn't match up. If you added thickness to give the hinge better purchase and that area of TE more strength, the un-strengthened TE on either side wouldn't really be strong enough. Bottom line is you'd need to find very dainty CA hinges. If you did, then whatever they were supported by would be good enough.
Look for the smallest CA hinges and if what's sticking out bothers you, trim them to fit before installing.
CA hinges aren't exactly the most free hinges. So you wouldn't want to use large CA hinges if your TE and aileron widths were really 1/4". Because the structure wouldn't be very strong and the hinges probably be too stiff for whatever servos were in such a light structure. You'd really need to find the very thin and small CA hinges and they probably still would be somewhat stiff for any somewhat delicate structure.
But don't worry about adding structure to cover all the hinge, because the rest wouldn't match up. If you added thickness to give the hinge better purchase and that area of TE more strength, the un-strengthened TE on either side wouldn't really be strong enough. Bottom line is you'd need to find very dainty CA hinges. If you did, then whatever they were supported by would be good enough.
Look for the smallest CA hinges and if what's sticking out bothers you, trim them to fit before installing.
#3
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RE: CA hinge questions
Yeah, if it's a fun fly or 3D model where the surfaces will need to move over very large angles then I would say that the CA hinges are going to be a bit stiff for that. If it's for a more or less normal amount of throw like + 15 degrees or less then just add little hinge blocks to the 1/4 sq, wick in the thin CA and don't worry your pretty head about it. As you suggested you're overthinking it too much.
Remember that the edges need to be beveled to a >< sort of meeting line so the surfaces can move without binding. If it's 1/4 sq then you're shaving off quite a lot if it's a 3D type model. If it's lower movement angles then just a bit of angle will be fine.
Remember that the edges need to be beveled to a >< sort of meeting line so the surfaces can move without binding. If it's 1/4 sq then you're shaving off quite a lot if it's a 3D type model. If it's lower movement angles then just a bit of angle will be fine.