Flight Testing of a Fan-in-Fin Antitorque and Directional Control System and a Collective Force Augmentation System (CFAS)
Abstract
A research flight test program was conducted to determine the characteristics of the fan-in-fin antitorque and directional control concept compared with a conventional tail rotor in the areas of stability, control, power requirements, aerodynamics, and overall aircraft performance. For the program, the tail rotor of Sikorsky's S-67 Blackhawk helicopter was replaced by a ducted fan, mounted in a new vertical tail. The modified aircraft was flight tested under a test plan that provided direct comparison with the baseline aircraft. The fan-in-fin demonstrated that its advantages in compactness and increased safety in ground operation can be realized without significant performance penalty or unpredictable impact on handling qualities. Although some shortcomings were experienced, test results confirmed that the fan-in-fin is an acceptable alternate to the tail rotor in applications where the reduction in operational hazards provided by the fan is essential. A collective force augmentation system (CFAS) was also evaluated on the S-67 helicopter. The purpose of CFAS is to keep main rotor loads within acceptable limits during high-speed maneuvering flight by introducing a force-feel cue to the pilot's collective control stick. Flight tests proved the CFAS capable of providing the pilot with the proper force cues to maneuver the helicopter to the boundary of the main rotor load limit.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1975
- Accession Number
- ADA013407
Entities
People
- David R. Clark
- David Verzella
- Wilfried H. Meier
- William P. Groth
Organizations
- United Technologies Corporation