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Rudder spar bent?

Mikeandmaz

Active Member
Hi All,
I?m very new to the RV build world and am starting the Rudder build. I?ve noticed that the Spar is slightly bent. It?s measuring 3/32? off the work bench at one end when lying flat. Is this an allowable amount or do I need to try to straighten it somehow? I know the thicker pieces can arrive bent, ive straightened the VS Doubler but what about the Rudder Spar?
Mike
 
Hi All,
I?m very new to the RV build world and am starting the Rudder build. I?ve noticed that the Spar is slightly bent. It?s measuring 3/32? off the work bench at one end when lying flat. Is this an allowable amount or do I need to try to straighten it somehow? I know the thicker pieces can arrive bent, ive straightened the VS Doubler but what about the Rudder Spar?
Mike

You will find it necessary to "encourage" most of the long parts to align with the hole patterns, as the forming/punching/bending process builds in some stress that tends to curve. The preload from this is negligible compared to the design loads on the structure in flight. Do not try to straighten the spar before riveting, you're more likely to crinkle than improve (a more extreme example of this will be the fluting of ribs once you get to that point). The manual will state clearly which parts need straightening, e.g. HS attach brackets; the VS doubler didn't, but it doesn't hurt now that you've done it.
 
Hey Mike,
Welcome to the RV world. Sounds like your very particular..and that's a good thing when you're building an airplane in you garage. After some time, you'll get a better feel for when something isn't right and know when to "make the call" to HQ in Oregon. I think one of the most difficult things for me initially was not knowing when the materials, or my work wasn't acceptable. I started with high expectations thinking I would build the perfect airplane. Over time, that goal has changed to building a SAFE airplane.
Regarding your rudder spar...I think it's ok. Just for a test though. Try clecoing the rudder skins to the spar. The clecos have a little more slop/tolerance than the rivets, but it will give you a idea of what you're dealing with.
Good luck and enjoy the experience!
 
Welcome Mike,

Just wait until you start working with J-channel material and dimple it. It puts the a bow on the J-channel. You don't think it'd ever fit but it gently bends back to straight.
 
Thanks for the replies. I’m aware that one of my many failings is to think I can just carry on and wing it and it will be alright! I’m trying to be a bit more particular with the build, I guess maybe a bit too much, that’s a relief!
Looking forward to the “journey!”
 
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Just make sure you clamp everything tight before you rivet or there will be gaps between the spar and the angles. Spring-loaded clamps won't do it......
 
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