In order to develop its future vertical lift (FVL) platforms in a timely and affordable manner without having the helicopters become obsolete before they ever see combat, the Army must require commonality among the various designs, said Nick Lappos, who chairs the Vertical Lift Consortium board of directors.
“Is there a reason why ever flying machine has to have a cockpit design team design that cockpit?” Lappos, also senior technical fellow of advanced technology at Sikorsky, said July 22 at the Center For Strategic and International Studies in Washington. “That every flying machine has to have generator control units to put on the generators and hydraulic elements that are designed separately? It’s amazing how uncommon today’s systems are.”
The manufacturers of different Army helicopters use different words in maintenance manuals to describe the same parts, requiring maintenance personnel to be retrained from one aircraft to another, even within the same aviation unit, he said.
FVL is envisioned as a fleet of aircraft built on a common core airframe design that can be scaled to replace all of the Army’s current rotorcraft. The same basic design will have to perform the mission of the AH-64 Apache, UH-60 Black Hawk and the CH-47 Chinook.
An existing example is the Marine Corps’ fleet of attack and utility helicopters. The UH-1Y Huey and AH-1 Cobra are vastly different aircraft that perform distinct and specific mission. But the two designs are 80 percent common in parts, relieving Marine maintainers of a significant logistics challenge in the field because parts are interchangeable between the two.
James Kelly, F-35 logistics team lead for the Office of the Assistant Secretary of Defense for Logistics and Material Readiness, said commonality of systems has the potential to significantly reduce operation and sustainment cost of a program over its service life.
“Those are things we should definitely be doing in acquisition and sustainment strategies,” he said of reducing the cost and logistics burden of spare parts by requiring common standards across platforms.
The three F-35 variants were designed to be highly common, with 80 percent commonality of parts and systems between the A, B and C models. The same Pratt and Whitney F135 engine powers all three, for instance. Pratt & Whitney is a division of United Technologies Corp. [UTX]. Lockheed Martin [LMT] recently acquired Sikorsky.
But requiring commonality across the envisioned FVL fleet will be a first. Whereas the three F-35 variants are basically the same aircraft with differences in wing size and armaments, they are basically the same aircraft. The F-35B is the most unique because it has a lift fan module made by Rolls-Royce that allows for short takeoff and vertical landing.
Commonality of systems across platforms – both hardware and software – is one answer to speeding up development and testing, Lappos said. Boeing [BA] inserts common cockpit elements into all of its commercial aircraft, regardless of size. The Federal Aviation Administration (FAA) has cleared pilots that train and fly one size Boeing aircraft to seamlessly move to other variants with the same cockpit design.
The FVL consortium envisions a construct where the aircraft manufacturer receives major components like the cockpit and avionics systems from third-party vendors as furnished equipment. The same cockpit, at least major elements of it like displays and interfaces, would be required for multiple aircraft, rather than having each component specifically designed for a particular airframe, Lappos said.
To save time and money, FVL – which will have multiple mission sets and several models of aircraft based on a common core airframe – should have common elements like maintenance and crew stations, cockpits, training systems that are “relatively identical, or at least common,” he said.
There will be tradeoffs for the various FVL airframes in efficiency and payload capacity because those systems will not be ideally suited to the size and mission of the airframe, Lappos said. The cockpit for an Apache-size light attack helicopter will necessarily not be perfectly suited to a Chinook-sized heavy-lift rotorcraft.
“These systems that we’re talking about that will become common, do erode to some degree the payload of the system that they go into, because there is a natural price to pay for being slightly less than perfectly applicable,” he said. “There will be some tradeoffs to be made and some biting of the bullet by pilots and program managers to accept the system that comes from the cockpit program management team.”