Application: Ram Air Turbine
Problem: Develop compact, lightweight springs that can remain loaded for their lifecycle yet still retain rate and deflection if/when they are called upon.
For those of you who have never heard of a Ram Air Turbine, you are not alone. Like many life-saving devices employed throughout today’s society, the only time the public usually becomes aware of them is when they are responsible for saving the life of a loved one or in those heartbreaking situations when they fail. In the rare event an airplane completely loses power, a Ram Air Turbine is a small windmill designed to deploy from the hull of the aircraft and extract power from the airflow around the aircraft to generate enough power to reinstate the flight controls, instruments, and other functions essential to safely navigating and landing the plane as a glider.
In order to accomplish its deployment in the average time of 2-6 seconds, the actuator on the Ram Air Turbine needs springs that can store enough energy to not only push the turbine module down through the specially-designed bay doors, but soften the deployment so the speed of the aircraft does not rip the protruding device from the plane. MW Industries was approached about delivering such a line of high-quality, large bar diameter springs that could handle the strain of this particular application and perform without fail. Titanium Beta C was chosen for this application for its strength and weight-savings over steel.
While most applications of compression springs call for the spring to be at rest or partially loaded for their lifetime, the needs of the Ram Air Turbine application is quite the opposite. The springs inside the actuator are fully compressed for their entire lifetime, and must retain their initial rate and free length if the turbine is to function properly. Holding such a high force, over a long amount of time, in such a small area requires a very unique spring design made from excellent materials. The overall complexity of the turbine assembly means that each new design and model of the Ram Air Turbine undergoes extensive wind tunnel testing and design iterations before being installed in any commercial aircraft.
MW Industries is proud to assist in the manufacture of Ram Air Turbines. While we sincerely hope the need for their use never arises, we have and will continue to work hard so that when the time comes for a Ram Air Turbine to deploy, our springs will perform perfectly, and lives will be saved.