4130 or 1025?

[bluerooster]

Does anyone know what parts of the BC12D airframe are 4130, and what parts are 1025/1020?

[Hank Jarrett]

1025 and 1020 mostly used on pre war planes. 4130 on post war. 4130 is stronger and stiffer but the earlier steels will bend before breaking more. Both are plenty strong enough for a light plane but 4130 became the accepted material after the war and the earlier can be harder to find now.

Hank

[bluerooster]

Wag Aero offers 1025 seamless tubing. And for the part that I need to replace, it would do better than 4130, as to the cold forming aspect. I need to replace the curved part of the vertical stabilizer. And I'm afraid that 4130 would present problems forming the curve that 1025 wouldn't. Other than that, I would not have even asked. I would just use 4130 if it were a straight tube.

[bluerooster]

Also, I need to source some 3/4" channel which I haven't found. The 3/8" is everywhere. I guess I'll have to split a piece of square tube.

[bluerooster]

That would be great to have if it were legible.

[Fred-TA15A]

Sully, where did you get all those blue prints ?

Thanks
Fred

[sully]

They are L-2 drawings. They were provided by an owner that I did some repair work for.