The Gulfstream design is still subject to change, with a slide showing the nose receptacle having been a last-minute change to a presentation made to journalists last week, and the airframer has also considered a more traditional refueling position on the aircraft’s "crown", Troy Miller says. The nose-mounted nozzle is not an unusual choice, as both the USAF’s Fairchild Republic A-10 and Boeing B-1 have similar receptacles, he notes.
Mounting the receptacle on the aircraft's nose has little aerodynamic impact, and it may be closed when the G550 is not receiving fuel in-flight.
“There’s nothing particularly overwhelming about this design,” Miller says. “That’s why we’re so excited about it.”
No Gulfstream jet has ever been certificated for air-to-air refueling, although Miller argues its products' endurance has never necessitated the capability. However, the air force has a specific requirement for boom air refueling under the JSTARS recapitalization.
Still, the JSTARS replacement program did not catalyse Gulfstream’s exploration into air refueling. For years, the company has explored such an activity, conducting wind-tunnel tests and flight tests behind Boeing 707s to evaluate flight characteristics. In addition to engineering efforts focused on the boom receptacle, Gulfstream is exploring the probe-and-drogue refueling configuration used by the US Navy, Miller says.
“This is an ongoing project. It will be a new development, but it’s not new science to us,” he says. “Candidly, our engineers are excited about this and they don’t view this as a showstopper in any way.”
In 2006, Gulfstream and Israel Aerospace Industries (IAI) studied a tanker version of the G550. The JSTARS concept is limited to a Universal Aerial Refueling Receptacle Slipway Installation, however, with the aircraft to act only as a receiver.
“I won’t comment specifically on past efforts, but to say that the flexibility of these aircraft and its ability to do anything we’re talking about could lend itself to be a very potent air refueling asset, both as a receiver and as a tanker,” Miller says of the earlier study with IAI.
Miller declines to detail the refueling system under design at Gulfstream, except to point out that unlike its airliner-based competitors, the business jet stores its fuel in the wings rather than inside tanks. While the refueling capability is a new design revealed with the G550 JSTARS proposal, Gulfstream is leveraging a previously designed nose shape, he adds.
(Leigh Giangreco - FlightGlobal News)