Need help

[astjp2]

Ok, so I have done a lot of research on wing parts, in the drawings, they call out a spec for .0125 NICRAL sheet, I know its Nickel Chromium Aluminum alloy but what is an equivalent alloy? They also spec out 2s 1/2 hard, which spruce calls 1100 alloy but I have never seen a 1/2 hard pure aluminum, also 3s 1/4 hard, which I think is 3003, but I would like to confirm. Any factual info would be appreciated. Tim

[Ragwing nut]

1100 is dead soft, and the metal has temper. 3003 is 1/4 hard and commercial variant and really never used in aviation back in the day. More than likely it was 5052-O, which is the only variant I know of with chromium. Part is formed in O condition, then tempered

[astjp2]

My boot cowl is 3003, found a cub drawing that called out Nicral or 61s, and an old timer at the cub factory said he claimed that they used 6061t6 as a substitute for the nicral in .012” thickness. I went down a rabbit hole in looking at hundreds of blueprints. Got to bed at midnight and up at 430 heading to work!

[Scott]

I read or heard the same thing recently.. that piper used 6061T6 .012" for the truss ribs and called it NiCral. But I can't for the life of me remember where I got that from (I've looked). Makes some sense as they seem to have used it a lot, spars for example.

I've spent many hours repairing piper truss ribs recently and the material certainly acts like 6061T6.
S