How is the Variable Exhaust Nozzle (VEN) operated?

• A. Electrically controlled system with a single motor.
• B. Hydraulically (fuel) operated series of actuators, synchronizing shafts, links, flags, seals, electrically controlled system.
• C. Pneumatically controlled only.
• D. Manually operated by the crew.

Answer: (B)

The Variable Exhaust Nozzle is operated by a hydraulically powered, electronically controlled network of actuators and linkages. A bank of hydraulic actuators positioned along the nozzle push and pull the nozzle petals in coordinated fashion, with synchronizing shafts and mechanical links ensuring all parts move together to achieve the correct exit area. Seals and related hardware manage fluid return and provide accurate position feedback. An electrical control system signals the hydraulic actuators to achieve the desired nozzle angle, giving precise, high-force actuation across the engine’s operating range. This setup is required because it provides the necessary force and synchronized movement that a single motor or pneumatic/manual system could not reliably deliver.