Abbreviations
| ABC | Advancing Blade Concept |
| ADT | Actuator disc theory |
| Aero. J. | Journal of the Royal Aeronautical Society |
| AFCS | Automatic flight control system |
| AGARD | Advisory Group for Aerospace Research and Development |
| AIAA | American Institute of Aeronautics and Astronautics |
| ARC | Aeronautical Research Council |
| ASE | Automatic stabilization equipment |
| AUW | All-up weight |
| BERP | British Experimental Rotor Programme1 |
| BET | Blade element theory |
| CFD | Computational fluid dynamics |
| CG | Centre of gravity |
| DOF | Degree of freedom |
| FAI | Fédération Aéronautique Internationale |
| FOM | Figure of merit |
| FUMS | Fatigue and Usage Monitoring System |
| HUMS | Health and Usage Monitoring System |
| IFR | Instrument Flight Rules |
| IGE | In ground effect |
| ISA | International standard atmosphere |
| JAHS | Journal of the American Helicopter Society |
| NACA | National Advisory Committee for Aeronautics (now NASA) |
| NFA | No-feathering axis |
| NFP | No-feathering plane |
| NPL | National Physical Laboratory |
| OGE | Out of ground effect |
| PIV | particle image velocimetry |
| RAE | Royal Aircraft Establishment |
| RAF | Royal Air Force |
| RLD | Really low drag |
| R & M | Reports and Memoranda of the ARC |
| SAE | Society of Automotive Engineers |
| SA | Shaft axis |
| sfc | Specific fuel consumption |
| SHM | Simple harmonic motion |
| SL | Sea level |
| SNP | Shaft normal plane |
| TPA | Tip-path axis |
| TPP | Tip-path plane |
| TRLF | Transmission loss factor |
| UAV | Unmanned aerial vehicle |
| UK | United Kingdom |
| USA | United States of America |
| VRS | Vortex ring state |
| VTOL | Vertical ... |
