B1.2 - Flight Test Instrumentation Blade Clearance Optical Measurement Method and Optimization In Scope of T625 GOKBEY Helicopter
- Event
- ETTC 2026 - European Test and Telemetry Conference
2026-06-09 - 2026-06-11
Nuremberg - Chapter
- Sensor I
- Author(s)
- B. A. Boztug, S. Soganci, S. Aydin, O. Cicek - Turkish Aerospace, Ankara (Turkey)
- Pages
- 181 - 190
- DOI
- 10.5162/ettc2026/B1.2
- Price
- free
Abstract
Blade clearance is a fundamental safety parameter in rotary-wing aircraft, governing the allowable distance between main rotor blades and nearby structures throughout the flight envelope. In helicopters, reduced clearance margins caused by pilot unintentional command inputs, structural deformation, rotor dynamics or installation tolerances may result severe safety problems. Blade clearance measurement and optimization studied within the scope of T₆₂₅ GÖKBEY Helicopter. Distance measurement methods are evaluated according to measurement interface requirements of T₆₂₅ especially, required sampling rate calculation which is based on time interval of rotary blade passing over tail cone. Optical principal sensor is selected according to requirements and adjustment flexibility of the sensor. To ensure measurement integrity, a stepwise verification and calibration strategy was applied. Initially, the sensor was evaluated in laboratory condition which is based on averaging optimization of sensor for measurement constrains. The second stage is static measurement tests conducted on helicopter in hangar condition. The test is performed to evaluate effect of helicopter environment and color optimization of target due to the wavelength of sensor for measurement accuracy improvement. After optimization, specific flight test campaign performed to obtain blade clearance margin which will be evaluated and verified with rotorcraft dynamic analyses team by rotor motion dataset of T₆₂₅. As next vision, the collected flight test data will be used to develop an artificial intelligent model in FTI Digital Twin Project to evaluate blade – structure interaction, enabling the estimation of tail cone contact probability through machine-learning techniques and supporting predictive safety assessments for extended flight envelopes.