Conduit bender for 4130 .035 tubing

[sideband]

Has anyone ever considered using a conduit tubing bender to make their longeron/tail feather bends? I'm planning on starting my XL build when I get back stateside and thought that would be way easier and potentially more accurate way to bend the tubing. I don't see any reason the aluminum tail feathers couldn't at least be done with inexpensive tubing benders.

[Larry H]

The conduit tube bender may make a larger radius bend than you want, then maybe not. One thing for sure is if you don't have a die/conduit bender with the correct diameter for your tubing, the walls of your tubing will egg shape out on the sides of the bend and or possibly collapse in on the inside side of your bend. If you have the correct size tubing die/conduit bender all you can do is test bend an extra piece and see how it comes out.

Larry H

[87924]

Since the leading edge of my vertical stab was going to be 1/2" 4130 steel, I used a 1/2" conduit bender to make the bends.  And just to be sure, I packed the tubing with sand before bending.  The conduit bender worked very well.  The other bends in the aluminum tubing, I did by hand, bending it around whatever was handy.  It really isn't that hard to do.  The longerons were bent by heating with a torch.  Worked well.

Paul

[sideband]

Paul, glad to see I wasn't the only one that thought of trying that and that it worked out well for you. I've got access to plenty of benders so I'm going to experiment with it to see how it turns out. I'm going to also be trying some strength and weight tests on different wing rib materials.

[scottiniowa]

 I'm going to also be trying some strength and weight tests on different wing rib materials.

What materials do you have in mind? and then changes in the covering?

[Larry H]

[quote author sideband
I'm going to also be trying some strength and weight tests on different wing rib materials.
[/quote]

Rib Material.
While I was waiting to receive my LEXL Kit I purchased a few pieces of 1X2 fur that had really straight aircraft quality grain. I cut them into 1/4 X 1/4 And made one rib from it just for the fun and experimenting. I weighed this rib on my digital scales. It weighed 4.6 oz, the spruce ribs weigh 4.2 oz. I'm not sure what other type of wood you want to try but the slow growing spruce is hard to beat for strength to weight in an aircraft.

Larry

[sideband]

I'd be using carbon fiber and aluminum. I live just off the gulf here in FL and would rather do aluminum wings than wood since it's so humid.

[Tom XL-7]

I appreciate your concern about high humidity.  That's a concern for the entire southeast and gulf states. We have days of 95 degrees and 95% humidity here in Ohio at times. I am sure that occurs across the midwest where there are hot summers with ample rain.
 The only complaint I hear eaglers having is the leading edge deforming due to humidity-induced swelling. The idea of a composite nose has occurred to me.
  You have said twice " aluminum and carbon fiber" in two posts.  I would suggest aluminum or composites. They are two different animals.
 If I were to build an aluminum wing the easiest leading edge would be to rivet aluminum on there. The aluminum wing would look a lot like the wood one, just aluminum.
 Composites open a whole world of design options.  
Now a simple glass nose skin would epoxy right onto the wood.  Same as the plywood. Not quite as easy onto an aluminum spar. A little extra effort. But I have seen composites mechanically fastened before. In composite construction, it is easy to get light and strong. What gets tricky is attaching the hard points and distributing the loads.  Examples: suspension, engines transmissions, or in our case wing mounts and strut mounts. There is more to it than drilling a hole and sticking a bolt through that super light thin skin.  It is done every day but would require some serious design effort.
 Just my two cents.
 Tom XL-7
We have quite a few threads running through here. Kind of like a chat room. We should start new threads when the subject changes. If we don't the overlords, I mean the moderators may have to correct us
 

[sideband]

Tom, thanks for the feedback. You're 100% right about fastening the CF to the aluminum. Once I get back and start making these test pieces I'd love to get more feedback and ideas on these wing mods. I truly believe the aluminum wing can be done easier and lighter than wood with the right tooling and approach.