Visibility tests complete for SSBJs

 - December 1, 2008, 6:23 AM

NASA and Gulfstream last month wrapped up six weeks of flight testing at the Dryden Flight Research Center at Edwards AFB in California aimed at proving whether pilots can use high-definition video cameras and LCD monitors to take off and land a supersonic business jet (SSBJ) in lieu of natural forward vision.

Gulfstream partnered with NASA on the so-called external-vision system (XVS) project, conducted over the course of the last two months in a NASA F-18B to identify human factors issues associated with reduced forward visibility created by the elongated nose of an SSBJ.

More than a dozen flights were conducted using a combination of three Gulfstream test pilots, one NASA pilot and one FAA pilot. All involved primarily data collection, according to a Gulfstream spokesman. Most of the flights were in day VFR conditions and several were flown with another NASA “target” aircraft in the area to assess visual acuity of the system.

Two of the flights investigated multiple camera resolutions and lens combinations, while three night VFR flights were completed. The test flights concluded last month and the HD equipment was scheduled for removal by the end of last month.

Besides giving pilots a virtual view of the outside world, XVS would guide them to the runway, warn of other aircraft near their flight path and provide additional visual aids for approaches, landings and takeoffs. During the XVS test flights, the aft canopy was covered so that the pilot flying from the rear seat could see only a 22-inch HD display and through small holes to the sides. A safety pilot flew in the front seat.

Gulfstream is interested in developing an SSBJ, but only if its sonic boom can be reduced to the point that would allow supersonic flight over land. Gulfstream and NASA tested the structural integrity of a telescopic Quiet Spike sonic boom mitigator on a NASA F-15B testbed, but the OEM hasn’t released information about whether the design can indeed adequately suppress the boom caused when an airplane exceeds the speed of sound.

Made of advanced composite materials, the Quiet Spike weighed about 470 pounds and extended from 14 feet in subsonic flight to 24 feet in supersonic flight. Since 2004–when Gulfstream was awarded a patent for the Quiet Spike–the device had undergone extensive ground testing, including wind-tunnel tests, before being installed on the NASA F-15B for flight testing in the summer of 2007.