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Sikorsky-Boeing nears return to wind tunnel FLRAA testing

Sikorsky-Boeing is returning to the US Air Force’s (USAF’s) National Full-Scale Aerodynamics Complex (NFAC), located at Moffett Field in Mountain View, California, in March for additional wind tunnel testing of its US Army Future Long Range Assault Aircraft (FLRAA) effort.

The company will use the NFAC’s 12 m high × 24 m wide wind tunnel, which is one of two circuits at the facility. The team will again use a 1/5 scale SB>1 Defiant technology demonstrator model, Sikorsky spokesperson Melissa Chadwick said on 3 February. This is the same size model it used during a series of early 2019 tests at the complex to support SB>1 Defiant development, according to a USAF statement.

Sikorsky-Boeing’s wind tunnel testing is likely meant help to squeeze every last knot possible out of its design for the Defiant X that it is offering for FLRAA, according to Mike Hirschberg, executive director of the non-profit Vertical Flight Society (VFS). Hirschberg told Janes on 3 February that it is important for Sikorsky-Boeing to have a low drag design so the Defiant X can fly faster and can be more efficient by using less energy, fuel, and power to go fast. The SB>1 Defiant is the technology demonstrator while the Defiant X, which leverages lessons from SB>1 Defiant work, is the team’s formal FLRAA offering.

Hirschberg noted that it is expensive for companies to perform wind tunnel testing. Not only does a company have to rent a wind tunnel facility, but it must invest substantial amounts of money to create a sophisticated subscale model that accurately replicates, for example, the mechanical gearing inside a helicopter.

A scale model of the Sikorsky-Boeing SB>1 Defiant undergoes testing at the US Air Force’s National Full-Scale Aerodynamics Complex at Moffett Field in Mountain View, California, in November 2019. (US Air Force)

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