FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
2003
2003 - 0017.PDF
DEFENCE Windtunnel and flight test data is readily available for the RAAF's F-111 to be used for the trials TEST & EVALUATION GUY NORRIS / RENO 'Virtual' spoiler promises easier weapon release Joint USAF/RAAF trial will compare effect of active separation control on trajectories jectory differences in generic small smart bombs (SSB) with and with out the ASC activated. The ASC is a blowing device which injects nitro gen through a slot nozzle at the leading edge of the weapons bay. This produces a bow shock upstream of the bay cavity that causes flow - and the weapon - to be sucked out of the cavity behind the forward bulkhead. The US Air Force Research Labor atory (AFRL) has been studying Preparations are under way for joint US Air Force/Royal Australian Air Force flight tests of an active separa tion control (ASC) system intended to be a "virtual" spoiler and improve weapons bay acoustics as well as enhance weapon separation. An RAAF General Dynamics F-111G modified with an updated version of the ASC, first tested on the aircraft in 2001, will be used for the trial. The test's original objec tive was to compare separation tra- Poland to test PGM adaptor kit on Su-22 The Polish air force is set to start flight tests of a bolt-on wing adaptor kit developed as part of a package to convert unguided bombs to precision- guided munitions. The flight tests, to be conducted using a Sukhoi Su-22M4, are expected to follow a cautious build-up approach after the Polish air force institute of technology found potential danger points in the launch profile. Using a six degree of freedom simulation model based on predicted aircraft and store aerodynamic loads, the institute evaluated the expected behaviour of a "Type A" store throughout a release envelope covering adapter sweep angles from 0° to 30° and aircraft angles of attack (AoA) from 0° to 6°. The institute adopted the simulation model to reduce development time and cost in comparison with similar US adapter kit efforts. These include clearance of the Raytheon AGM-154 JSOW stand-off weapon on the Boeing F/A-18 Hornet to Mach 0.95 which took 20 flights and more than 400h of windtunnel tests. For the clean aircraft configuration, tests predict the most hazardous release point will be with wing sweep angle at 30° or more and aircraft AoA at around 3°. "The dangerous mode is a nose-in yawing motion that moves the store wing towards the aircraft's fuselage," says the team. alternatives to spoilers since 1993, and says the system could be an option on the Lockheed Martin F-35 as well as for retrofit. Existing spoil ers project into the slipstream and "become a problem as the Mach number increases", says the USAF. It says circulation created by the spoiler also pushes the weapons nose-up towards the top of the bay, "which is also a problem". AFRL teamed for the tests with the RAAF Aircraft Research and Development Unit because wind- tunnel and flight-test data with and without the spoiler are available for the supersonic F-lll. Modifications to the ASC include the addition of supersonic slot noz zles to increase the penetration of the gas jets during supersonic flight. The jets' pulsing will also be redesigned to extend the blowing period from 0.3s. Although the ASC uses up to six 210bar (3,0001b/in2) nitrogen bottles, the USAF says future systems could use compres sor bleed air or a environmental control system supply. In the first tests, 16 SSB inert shapes were released from the right side of the modified bomb bay dur ing eight sorties. Results showed the system reduced the tendency of the aft bomb to pitch up by over 8° in subsonic launch conditions, while acoustic levels were also reduced. No major differences were seen dur ing supersonic launches, hence the modifications for the next phase. PROCUREMENT Watchkeeper decision time moves closer Companies competing to be downselected for the UK's Watchkeeper intelligence, sur veillance, target acquisition and reconnaissance programme expect a decision by the end of this month. Industries sources say the decision could accompany the selection of the future aircraft carrier prime contractor. Watchkeeper will include unmanned air vehicles (UAV) and the intelligence gathering, exploitation and dissemination infrastructure. The Ministry of Defence says it is seeking "the soonest possi ble" decision, potentially this month, but warns that the com plexity of the programme means further slips could occur. Defence secretary Geoffrey Hoon in July last year signalled that Watchkeeper would be accelerated Flight International, 23-29 July 2002). A decision had been expected shortly after that. Industry and MoD sources say questionnaires and answers have held up the downselection. A plan to create a joint service UAV evaluation programme has also caused delays, they add. The delay means that the four teams - led by BAE Systems, Lockheed Martin, Northrop Grumman and Thales - have been self-funding their work since August, when the original downselection was due. Meanwhile, BAE is preparing answers to a series of questions on the lease of 30 Hawk trainers to the Royal Air Force. BAE submitted an unsolicited bid in late 2001, seeking to ensure that the Hawk is the pre ferred advanced trainer within the proposed UK Military Flight Training System. The MoD says it "is working with BAE" to ensure the aircraft meets the UK's needs, to the necessary timetable and "at the right price".This has included benchmarking against other trainers, says the MoD, including the Aermacchi M346. www.flightinternational.com FLIGHT INTERNATIONAL 14-20 JANUARY 2003 15
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
