The Bell Helicopter-Boeing [BA] tandem that develops the tilt-rotor V-22 Osprey helped create an air filter-like device that could “double or triple” the lives of V-22 engines by filtering out sand and other tiny particles that enter through air, according to a Bell Helicopter executive.
Bell Helicopter Vice President of Military Business Development Rich Linhart told Defense Daily Bell-Boeing originally self-funded development of this filter, known as an inlet barrier, because it discovered sand and other fine particles in theaters like Afghanistan were eroding the Rolls-Royce-developed AE 1107C engines on V-22s. Linhart said even though warfighters were performing maintenance like cleaning engines after flight, it was not enough to stem the tide of erosion. But Bell-Boeing believes it found a solution that could extend the lives of V-22 engines, Linhart said.
“We estimate that (the filter) will double or triple the life of the engines, get back to the original specification of the engines to start with,” Linhart said at the Air Force Association’s (AFA) annual conference here.
Bell Helicopter V-22 Advanced Derivatives Manager Chad Sparks told Defense Daily on Sept. 24 company resources funded all research and development (R&D) up through a prototype demonstration. Sparks said Bell-Boeing built hardware and used a V-22 leased from the Defense Department in November 2011 as the primary platform for installing the prototype and testing.
After understanding how the engine and airframe perform with that different inlet, Sparks said the company put the inlet through “aggressive” tests at Kirtland AFB, N.M., to validate the proof of concept. Sparks said engine performance was favorable, while Linhart said those tests demonstrated the filter’s ability to clean the air of 98 percent of particles in the atmosphere.
“What we were really looking for was the benefit of engine time on wing,” Sparks said. “We were able to support those estimates that we had based on the data we saw at Kirtland. It was a very positive test.”
DoD is now funding Bell-Boeing for the initial predesign phases for the production solution, Sparks said, where it will leverage what the company did as an industry investment for a prototype and integrate it into a full solution. Air Force spokesman Ed Gulick said the service requested $19.3 million in fiscal year 2014 to begin an effort to find an improved inlet solution and that Bell-Boeing’s internally-funded inlet barrier filter is one possible solution.
Naval Air Systems Command (NAVAIR) spokesman Jim O’Donnell said the Office of the Secretary of Defense (OSD) added $73.7 million in research development test and evaluation (RDT&E) funds from FY ’14 through FY ’17 for development of an Improved Inlet Solution (IIS) to reduce V-22 sand ingestion problems. Bell-Boeing is currently funded for an initial stage, Sparks said, and there is another contract the company will have to follow to complete that effort. Sparks said whether the filter reaches production is dependent on the government contracting cycle, which is currently faces declining defense budgets.
Bell-Boeing considered three or four different solutions for its sand erosion problem, which Linhart said it started working to fix about two-and-a-half years ago. Sparks said others solutions considered for the fix included an upgrade to the engine’s current centrifugal force solution that uses a set of blowers and some inlet guide veins to spin the air and eject particles out throw a lower nacelle. Swirl tubes were also considered, Sparks said, but when considering all options, Bell-Boeing felt inlet barrier filters would give the best engine time on wing performance when considered with the V-22’s typical weight, aerodynamic and engine performance.
Linhart said the inlet barrier Bell-Boeing ultimately selected fits over the front of the engine’s nacelle and takes about an hour to clean, which he said is key since warfighters were spending over an hour trying to clean the engine after every time it flew, a sunk cost as sand had already damaged the engine.
Minnesota-based air filter manufacturer Donaldson [DCI] collaborated with Bell-Boeing on the inlet barrier filter, contributing to the initial creative process of how to apply inlet barrier filters to a V-22, Sparks said.
“There’s some very unique ways in which, from both a geometric installation and (V-22 air speeds) that are much different than other installations they have done on other platforms,” Sparks said about Donaldson, which he said partnered with Bell-Boeing in the past on the OH-58 Kiowa Warrior military helicopter.
Sparks said the inlet barrier would work both on the Marine Corps’ variant of the V-22, the MV-22, as well as the Air Force’s CV-22 variant as the inlet is identical for both aircraft. Sparks said the CV-22 may have a more pressing need as the Air Force tends to put its aircraft in more challenging and austere environments than the Marine Corps does.
Bell Helicopter is a division of Textron [TXT].