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Aviation History
1993
1993 - 1025.PDF
DEFENCE NASA achieves engine-only landing control NASA achieved a milestone in its propulsion-control programme by setting down its McDonnell Douglas (MDC) F- 15 research aircraft, using only engine power for control. NASA views the success as a potential breakthrough in civil and military flight safety. The modified F-15, which is the testbed aircraft for the highly integrated digital-en gine-control concept, made the touchdown at NASA's Dryden Flight Research Center at Ed wards AFB, California. The air craft landed during a touch- and-go, with its flight controls deliberately locked. The touchdown was a major step for the programme, which is aimed at developing the con ventionally powered F-15 to the point where it can be ma noeuvred, and landed safely, without any working aerody namic-control surfaces, using engine power alone. The US Air Force is consid ering an upgrade of the Hughes APG-63 multi-mode radar used in its McDonnell Douglas F-15C/D fleet, using elements of the McDonnell Douglas F-18's APG-73 radar. Although it is an upgraded version of the APG-63, the APG-70 is still being produced for the last few USAF F-15Es being built and is fitted some later C/D models. The APG- 63U — as the upgrade would be called — would use the core of the APG-73 radar data-and- signal processor. The APG-73 is an upgraded radar developed from the APG-65. "We're not under contract yet, though we hope to be by the end of the year," says Hughes Radar Systems F-15 marketing manager Larry Fritsch. "The upgrade will ad dress the partial obsolescence issues in the current -63. The whole thing came about be cause hundreds of parts are not procurable anymore." . Fritsch says that the use of the -73 processor, "...though The study evolved from the US Air Force's self-repairing programme, used to evaluate ways of keeping an aircraft flying despite major damage. "In this [self-repairing] pro gramme, we failed the stabila- tor and the aircraft automati cally re-configured all other control surfaces to 'weird' posi tions. It did exactly what it was supposed to do, but we saw examples where all surfaces would fail due to hydraulic failure," says NASA project manager Dr James Stewart. "Even with hydraulic failure, you still have the thrust of the engines available to you and that's what we started looking at. Most of those involved thought it was impossible to do, but what we were thinking of was only the kind of simple manoeuvring you need to come back to land." Early tests showed that crude control could be achieved in not completely defined", would improve the current radar's supportability, as well as pro viding increased throughput speed and an expanded mem ory. If sanctioned, production deliveries for the APG-63U pro gramme could begin in 1997. The work would be welcome news for Hughes, with the last APG-70-equipped F-15E due to be delivered to the USAF within the next two months and a gap opening up until first deliveries of the Saudi Arabian F-15S. "In addition to the Saudi Arabia procurement, we hope the USAF will exercise an option to add on between 24 and 40 aircraft spread over three years. This could be tagged on to the Saudi buy," says Fritsch. • Flight tests of the Hughes APQ-180, a modified version of the APG-70 fitted to the Lock heed AC-130U gunship being developed by Rockwell, are due to be completed in June. Hughes delivered 12 of the radars, which are modified with an antenna that provides 180° coverage. • ideal conditions through man ual throttle control, but the programme goals could only be achieved by the use of high- fidelity digital control. This was re-inforced by the Sioux City crash of a United Airlines McDonnell Douglas DC-10 in 1989, shortly after the NASA programme began, which occurred during an at tempted landing, using engine power alone for control after flight-control failure. NASA has gradually built up to the touchdown through the introduction of advanced- control technology such as the vehicle-management system (VMS). Developed jointly with MDC and Smiths Industries, it augments the on-board com- Marconi Defence Systems (MDS) has completed ac tive trials of its Apollo radar- jamming pod as part of a company-sponsored system- qualification programme. The pod was carried by a Flight Operations "electronic aggressor" Learjet 35 and used successfully against I/J-band threat emitters on a UK Minis try of Defence range. The trial, carried out in late March, com plements the system's aero dynamic clearance, obtained on a Dassault Falcon 20 in 1992. In its podded form, the Apollo is a software-controlled noise and deception jammer, weighing about 130kg. Its baseline I/J-band frequency coverage can be extended up or down and it can be used as puters and provides high-speed integration and control of flight-critical systems. The pilot, in this case former astronaut Gordon Fullerton, used a specially developed cockpit system to control the aircraft, which is tailored to fly with a digital flight-control sys tem taking commands from the VMS. Two thumb wheels are used to control the movement of the aircraft. One of these is used for pitch, which is achieved using simultaneous power changes to both engines, and the other is for banking turns, using the control to input differential power settings. NASA says that flight tests will be completed by July. D stand-alone equipment or be integrated with the MDS Sky Guardian family of radar- warning receivers. The Apollo is also offered in internalised and scab-mounted formats. The pod is already being marketed actively — to exist ing and potential British Aero space Hawk 100/200 cus tomers, among others — and may be tested in Sweden later this year in connection with the JAS39 Gripen programme. In addition, it is being pro moted for civilian contract- training use, including possibly the UK's current contract elec tronic-warfare training compe tition, the outcome of which is expected in June/July. MDS declines to comment on uses or potential customers. D USAF may upgrade APG-63 radar The Apollo pod: successful in UK tests MDS completes Apollo pod trials 18 FLIGHT INTERNATIONAL 5-11 May, 1993
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