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Good day, all. I am currently in the midst of plans-building my 750. I broke my bending brake on some of the thicker bends, and I am currently rebuilding. Since it is currently only 8' long, I'm wondering if that length will suffice for a future plans-built CH 640. The longest bend in my 750 was just over 8.5', so I had to bend my tail section spars on a different brake. But, since I'm repairing/redesigning anyway, I'd like it to accommodate a 640 project in the future. Anyone know what the longest bends in a 640 are? I plan to build one after my 750 is finished. Thanks in advance, Greg.
I wanted to get your thoughts on metal working in cold weather. Is there any concerns about shaping metal during the winter months in an un-heated garage? I did a quick google search and didnt find much.
Forming ribs, bending brake usage...etc?
That's a tough one. I formed a lot of my parts at different times of the year, sometimes when the metal was cold, sometimes warm. I heat my garage, but only when I'm working in it, so a lot of the time I'm working with metal that hasn't had a chance to warm up. I have not noticed any mis-matching between parts made in colder weather vs. warmer weather upon assembly. Where I suspect you may notice it, if at all, would be on the larger structures like the wings and fuselage, where you might get some very minor "oil canning" across some unsupported skin areas with changes in the season.The expansion and contraction is slight, though, in the temperature swings we're worried about. As long as you match-drill your parts when they are the same temperature, you really shouldn't have a problem. But I wouldn't worry too much about it unless your temperature ranges are really severe. And even then, it should be very a very minor issue.
There may be some other folks with different experiences on the forum here. I'm in mid-Michigan, where we have pretty moderate temps most of the time. One of the well-known concepts in airplane building, though, is that you don't need a controlled climate like with composite or wood construction. I really wouldn't worry too much about it.