Reference Documents
Authoritative third-party standards, specifications, and source documents the OpenSkyhawk build relies on. These are external references (not OpenSkyhawk-authored); the project standards derived from them live under docs/_source/ and docs/hardware/.
MIL-F-25173A — Fastener, Control Panel, Aircraft Equipment
USAF / Navy Bureau of Aeronautics (Aeronautical Standards Group), 16 Feb 1956 — supersedes MIL-F-25173(USAF), 1955.
What it represents: the dimensional + performance standard for the quarter-turn stud + receptacle-strip ("Dzus rail") fastener that mounts aircraft equipment control panels. It is the basis for the OpenSkyhawk Dzus rail panel-mounting standard (panel width, screw spacing, hole grid).
Key dimensions (Figures 1–2):
| Element | Spec |
|---|---|
| Receptacle-strip hole grid | 3⁄8″ (9.525 mm) pitch (±.005″/ft cumulative) · holes drilled .242″ · strip ~.637″ wide |
| Receptacle strip (the rail) | Dzus P/N PR 3½-L (or equal), cut to length · .051″ music-wire spring (QQ-W-470) · aluminum (QQ-A-325, T6) · cadmium plated (QQ-P-416) |
| Stud head | Ø .375″ (9.53 mm) · .625″ dome radius · .050″ screwdriver slot |
| Stud body / shoulder | body Ø .257″ (6.53 mm) · bearing shoulder Ø .315″ (8.0 mm) |
| Panel | 1⁄16″ (1.59 mm) thick · quarter-turn lock (85–135°), positive stop |
| Stud detail design | left to the fastener manufacturer within the Figure-2 envelope — no single mandated stud part number |
Applied in: the OpenSkyhawk Dzus rail panel-mounting standard — panel width 146.05 mm (5¾″), mounting-screw centers 136.5 mm (5⅜″), 3⁄8″ vertical pitch — see mechanical-standards.md.