Category 9 - Aircraft - helicopter
MIL-STD-810H, Environmental Engineering Considerations and Laboratory Tests
Last Updated 29 Oct 2026
Hover any section to copy its link or text, ask Copilot about it, or bookmark it.
2 tables appear under this heading.
1. PDF page 415
| Helicopter | MAIN ROTOR | TAIL ROTOR |
|---|
| Rotation Speed 1P (Hz) | Number of Blades n | Rotation Speed 1T (Hz) | Number of Blades m |
|---|
| AH-1 | 5.40 | 2 | 27.7 | 2 |
| AH-6J | 7.95 | 5 | 47.3 | 2 |
| AH-6M | 7.92 | 6 | 44.4 | 4 |
| AH-64 (early) | 4.82 | 4 | 23.4 | 4 |
| AH-64 (late) | 4.86 | 4 | 23.6 | 4 |
| CH-47D | Refer to TOP 01-2-603 (Paragraph 6.1, reference xx) |
| MH-6H | 7.80 | 5 | 47.5 | 2 |
| OH-6A | 8.10 | 4 | 51.8 | 2 |
| OH-58A/C | 5.90 | 2 | 43.8 | 2 |
| OH-58D | 6.60 | 4 | 39.7 | 2 |
| UH-1 | 5.40 | 2 | 27.7 | 2 |
| UH-60 | Refer to TOP 01-2-603 (Paragraph 6.1, reference xx) |
2. PDF page 416
| Main or Tail Rotor Frequencies (Hz) Determine 1P and 1T from the Specific Helicopter or from the table (below). | Drive Train Component Rotation Determine 1S from Specific Helicopter and Component. |
|---|
| f1 = 1P | f1 = 1T | | f1 = 1S | |
|---|
| f1 = 1P | f1 = 1T | fundamental | f1 = 1S | fundamental |
| f2 = n x 1P | f2 = m x 1T | blade passage (BP) | f2 = 2 x 1S | 2nd harmonic |
| f3 = 2 x n x 1P | f3 = 2 x m x 1T | 2nd harmonic | f3 = 3 x 1S | 3rd harmonic |
| f4 = 3 x n x 1P | f4 = 3 x m x 1T | 3rd harmonic | f4 = 4 x 1S | 4th harmonic |