4130 wing struts?

[milanesa711]

Hello, for some reason unknown to me, today is easier to get 4130 to 6061, price and availability, only that I need to finish my Xl to-40.
Which 4130 tube can be used for the wing struts? It is heavier but my xl is a full vw, not far103 ... Thanks !!!!
Martin Bianco
 Argentina

[Vince Carucci]

My plans are for the standard LE. I believe it calls out for 1.25 x .058 6061 Aluminum. If the XL calls for the same, than the following numbers might work.  I encourage you to get a second opinion on these numbers.

6061 Aluminum (.26 lb/ft)      1.25 x .058  = .217 in² with a yield strength of 40,000 psi =  8687 lbs force.
4130 Steel (.454 lb/ft)             1.25 x .035 =  .134 in² with a yield strength of 63,100 psi  = 8429 lbs force.

Those numbers should be many times more than the stresses experienced during flight even if you consider the stress concentration points around the mounting bolts. Again, get a second opinion.

Note: the plans then show 1-1/8 x .035 steel tubing at each end of the strut. There lies the weakest link in the strut.

Vince

[milanesa711]

Thanks Vince!! I keep searching....
Yes the 11/8 at the end of the struts is the weakest point
Thanks!!!
Martin Bianco
Argentina