Unit conversions¶
RFM wants everything in metric (watts, kg, metres, kg·m²). Most manuals aren't, so:
| From | To | Multiply by |
|---|---|---|
| shp (shaft horsepower) | W | 745.7 |
| metric hp (PS, л.с.) | W | 735.5 |
| lb | kg | 0.4536 |
| ft | m | 0.3048 |
| in | m | 0.0254 |
| ft² | m² | 0.0929 |
| slug·ft² (= lb·ft·s²) | kg·m² | 1.356 |
| lb·ft (torque) | N·m | 1.356 |
| US gal Jet A / JP-8 | kg | ≈ 3.07 |
| lb/h | kg/h | 0.4536 |
| kt | m/s | 0.5144 |
| ft/min | m/s | 0.00508 |
| psi | kPa | 6.895 |
| rad | deg | 57.296 |
Quick tip speed check: tip speed (m/s) = 2π × radius × RPM ÷ 60. Real main rotors usually land around 200–250 m/s (UH-1 248, Mi-8 214). If yours is way outside that, double-check your radius and RPM.