HexWeb HRH-10 density classes (1/8 in cell)
Where to buy| Designation | Density, lb/ft³ | Density, kg/m³ (converted) | Bare compressive, psi typ | Plate shear L, psi typ | Plate shear W, psi typ |
|---|---|---|---|---|---|
| HRH-10 – 1/8 – 1.8 | 1.8 | 29 | 105 | 90 | 50 |
| HRH-10 – 1/8 – 3.0 | 3.0 | 48 | 300 | 175 | 100 |
| HRH-10 – 1/8 – 4.0 (2.5 mil) | 4.0 | 64 | 520 | 255 | 140 |
| HRH-10 – 1/8 – 5.0 | 5.0 | 80 | 700 | 325 | 175 |
| HRH-10 – 1/8 – 6.0 | 6.0 | 96 | 1,050 | 385 | 200 |
| HRH-10 – 1/8 – 8.0 | 8.0 | 128 | 1,675 | 480 | 260 |
| HRH-10 – 1/8 – 9.0 | 9.0 | 144 | 2,000 | 515 | 300 |
Hexcel HexWeb HRH-10 product data sheet (inch version), mechanical properties table, tested per AMS-STD-401 at 0.500 in core thickness. Designation is material, cell size in inches, nominal density in lb/ft³. Density tolerance is ±10 % measured on at least 100 in³ of core. Other cell sizes (for example 3/16) and densities are in the same table. kg/m³ converted at 16.02 per lb/ft³.
Cell shapes and direction (FAA-H-8083-31B, p. 7-11)
Core cells for aerospace are usually hexagonal. Sheets are bonded at set lines and expanded; the direction parallel to the sheets is the ribbon direction, and strength differs between ribbon (L) and transverse (W), as the plate shear columns show.
Bisected hexagonal core adds a sheet across each hexagon and is stiffer and stronger. Overexpanded core has rectangular cells, flexible across the ribbon, for simple curves. Bell-shaped (flexicore) core is flexible in all directions, for complex curves.
Small cells support the face sheets better; higher density gives stronger, stiffer core. Aramid paper (Nomex or Korex) is the most common aircraft core; fiberglass core is used for higher strength.
In a repair
Replacement core must be the same material and density as the original, or an acceptable substitute, cut to fit snugly, with the direction of the original core observed (AC 43.13-1B, paragraph 3-2c). Core that has taken in water is a damage case, not a drying job: see sandwich repair.
Questions people actually ask
What does 3.0 mean in HRH-10 – 1/8 – 3.0?
Nominal density of 3.0 lb/ft³ (about 48 kg/m³). Cell size 1/8 in, material HRH-10.
Limits — when NOT to use this
- One family. HRH-10 values are typical numbers from one datasheet.
- Not a substitution table. The SRM names the core.
Where to buy
Distributors coming soon.
Sources
- Hexcel HexWeb HRH-10 Product Data Sheet (inch) — designation, density tolerance, mechanical properties table.
- FAA-H-8083-31B, AMT Handbook — Airframe, Volume 1 (2023), Chapter 7 — honeycomb core materials, cell types, density (pp. 7-10 to 7-11).
- AC 43.13-1B, Change 1, Chapter 3, Fiberglass and Plastics — paragraph 3-2c (p. 3-3): replacement core.