CH-53K program conducts successful auxiliary power unit Light-Off

The CH-53K Heavy Lift Helicopter Program has achieved “Ready to Load” (RTL) condition with the successful light-off of its first Auxiliary Power Unit (APU) engine.

The achievement signals that the program is ready to begin formal integration testing in early 2011.

The APU provides power to a 45KVA generator, a 58-horsepower hydraulic pump and hydraulic starter, and also provides bleed air to an environmental control system and main engine start system. It is used for ground operations, main engine start, and conditions when main electrical power provided by the aircraft’s main generators is lost. It is a critical element of the aircraft’s design.

“This successful test is yet another giant step forward for the CH-53K helicopter program. Compared to its predecessor, the CH-53E helicopter, the CH-53K helicopter will offer better durability and reliability, which translates into lower life-cycle costs for the customer,” said John Johnson, CH-53K helicopter program manager.

The APU achieved RTL condition after light-off at 100 percent speed sustained for 30 seconds. The engine is now being prepared for safety of flight testing and accomplishing the on-time delivery of hardware for the ground test vehicle.

The APU Light-Off test was conducted at the San Diego facility of Hamilton Sundstrand, a United Technologies Corp. business unit. Hamilton Sundstrand (HS) is the primary supplier for the secondary power system for the CH-53K heavy lift helicopter program. HS is providing the APU, environmental control system (ECS), and the main engine start system consisting of an air turbine starter and start control valve.

The entire APU development and qualification program will involve 13 engines – seven for Hamilton Sundstrand and six for Sikorsky. The APU is a critical part of the secondary power system on the CH-53K helicopter, providing a pressurized air source (“bleed air”) for the Hamilton ECS and main engine start system, as well as shaft power for the Goodrich 45KVA generator and Eaton 58- horsepower hydraulic pump.

Sikorsky Aircraft received a $3 billion System Development and Demonstration (SDD) contract on April 5, 2006 to develop a replacement for the U.S. Marine Corps CH-53E heavy lift helicopter. The new aircraft program is planned to include production of more than 200 aircraft. Currently, the CH-53K helicopter is in the SDD phase with all major subcontracts awarded and valued at over $1.1 billion.

The CH-53K helicopter will maintain virtually the same footprint as its predecessor, the three-engine CH-53E Super Stallion, but will nearly triple the payload to 27,000 pounds over 110 nautical miles under “hot high” ambient conditions. The CH-53E helicopter is currently the largest, most powerful marinized helicopter in the world.

It is deployed from Marine Corps amphibious assault ships to transport personnel and equipment and to carry external (sling) cargo loads.The CH-53K helicopter’s maximum gross weight (MGW) with internal loads is 74,000 pounds compared to 69,750 pounds for the CH-53E aircraft. The CH-53K’s MGW with external loads is 88,000 pounds as compared to 73,500 for the CH-53E helicopter.

Features of the CH-53K helicopter include: a modern glass cockpit; fly-by-wire flight controls; fourth generation rotor blades with anhedral tips; a low-maintenance elastomeric rotor head; upgraded engines; a locking cargo rail system; external cargo handling improvements; survivability enhancements; and improved reliability, maintainability and supportability. The program is expected to achieve the Initial Operational Capability milestone in fiscal year 2018.

Source: Sikorsky