Last week the US Navy awarded Boeing a US$219.6 million contract to develop the conformal fuel tanks – or CFTs – for the Super Hornet airframe, covering the “design, development, test and integration” of the conformal fuel tank.
However, it would be some years before US Navy and, potentially, RAAF Super Hornets and Growlers could benefit from the capability enhancer, as the work is not expected to be completed until mid-2022.
Boeing first proposed shoulder-mounted conformal fuel tanks for the Super Hornet as one of a number of upgrades for the jet, as part of what it would later call the Advanced Super Hornet, at the 2010 Farnborough Airshow. It then flew a Super Hornet demonstrator fitted with aerodynamic mockups of the tanks, along with other Advanced Super Hornet improvements, in 2013.
That testing validated the aerodynamic performance of the design and showed that CFTs would increase the Super Hornet’s combat radius by up to 130nm, for a total combat radius of more than 700nm.
The tanks have a combined fuel capacity of 1,600kg (3,500lb), do not increase the aircraft’s subsonic drag, and increase transonic drag only equivalent to carrying an external centreline tank. With some internal fuel system plumbing changes the CFTs were designed to be retrofittable to existing aircraft.
The US Navy added conformal fuel tanks to its ‘road map’ for the EA-18G Growler, which shares the same basic airframe as the F/A-18E/F Super Hornet, in 2015.
Conformal fuel tanks on the Growler would free up underwing stations, reduce drag compared to carrying underwing external fuel tanks, and improve the ‘field of regard’ for the aircraft’s ALQ-99 jammer pods (as underwing tanks can partially block their line of sight).
It is thought likely that the RAAF would acquire CFTs for its fleet of EA-18G Growlers (reduced to 11 aircraft following a recent engine failure on takeoff incident) should the US Navy fund their development. The 2016 Defence Integrated Investment Program roadmap of defence capability spending provides for some $5-6 billion in funding for upgrades to the Growler over the next decades.