Aircraft Structures and Composites Flashcards

Per AC 43.13-1B, what is the minimum edge distance for a single row of protruding-head rivets in sheet metal repair?

Answer: 2 times the rivet diameter

Minimum edge distance is 2D, measured from the rivet center to the sheet edge, which keeps the sheet from tearing out.

What is the minimum rivet pitch (spacing between rivets in the same row) generally recommended for aircraft sheet metal repairs?

Answer: 3D

Minimum rivet pitch is 3D. Closer spacing weakens the sheet between the holes.

A rivet head marked with a small dimple indicates which alloy?

Answer: 2117-T4 (AD)

The dimple is the head marking for 2117-T4 AD rivets, the most common structural rivet.

Why are 2024-T4 (DD) 'icebox' rivets kept refrigerated until use?

Answer: To delay natural age hardening so they stay soft enough to drive

Refrigeration slows natural aging after solution heat treatment, so the rivet stays soft enough to drive without cracking.

What are the standard dimensions of a properly formed shop (bucked) head?

Answer: 1.5D wide and 0.5D high

A correct bucktail is 1.5 times the shank diameter wide and 0.5 times the diameter high.

When calculating rivet length for a joint, what total length is normally selected?

Answer: Grip length plus 1.5D

Rivet length equals grip plus 1.5D, which leaves enough shank to form a standard shop head.

For a 90-degree bend in sheet metal, setback equals which value?

Answer: Bend radius plus material thickness

Setback = K(R + T), and K equals 1 for a 90-degree bend, so setback = R + T.