What controls the variable geometry?

What controls the variable geometry?

• A. FADEC
• B. HMU
• C. EPU
• D. Hydraulic

Answer: (B)

Variable geometry means the compressor’s adjustable vanes can change position to optimize airflow and engine performance at different speeds and loads. In the UH-60’s engine, the position of those vanes is controlled by the Hydromechanical Unit. The HMU provides the hydraulic signals that move the vane actuators, responding to power requests and engine conditions to meet the desired engine response. FADEC may monitor and coordinate engine operation, but the actual control of the variable geometry is driven by the HMU. The emergency power unit isn’t involved in setting vane positions, and while the hydraulic system powers the actuators, it’s the HMU that determines where the vanes go.

Variable geometry means the compressor’s adjustable vanes can change position to optimize airflow and engine performance at different speeds and loads. In the UH-60’s engine, the position of those vanes is controlled by the Hydromechanical Unit. The HMU provides the hydraulic signals that move the vane actuators, responding to power requests and engine conditions to meet the desired engine response. FADEC may monitor and coordinate engine operation, but the actual control of the variable geometry is driven by the HMU. The emergency power unit isn’t involved in setting vane positions, and while the hydraulic system powers the actuators, it’s the HMU that determines where the vanes go.