U.S. Supersonic Commercial Aircraft Assessing NASA's High Speed Research Program (1997) / Chapter Skim
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5 INTEGRATED AIRCRAFT
5 INTEGRATED AIRCRAFT
Pages 91-109
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From page 91... ...
system. Additional challenges are associated with the flight deck system (particularly with regard to the external visibility system EXVS]
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From page 92... ...
(For the HSCT, the essential problem is the small difference in frequency between the unstable attitude modes and the lowest structural vibration mode frequency, as shown schematically in Figure 5-1.) As a result, some active structural mode controls will be necessary.
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From page 93... ...
INTEGRATED AIRCRAFT ~5 Am 1 93 Critical frequency > separation \ 1 \ 1 Frequency of \ Frequency of unstable \ lowest structural attitude mode ~vibration mode Nyquist for pitch control loop FIGURE 5-1 Difference in frequency between unstable attitude mode and the lowest structural vibration mode frequency of the TCA design. Another area of concern is the amount of flow distortion at the engine inlets caused by non-zero side-slip angle or angle of attack.
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From page 94... ...
For example, increasing stiffness enough to produce structural vibration mode frequencies similar to the B-1 would probably more than double the structural weight of the TCA design. In any case, the efficacy of the TCA design would be severely diminished.
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From page 95... ...
Furthermore, structural-dynam~c effects and APSE interactions were not included in either the process used to select the TCA design configuration or the piloted simulations used to define the desired dynamic charactenstics of and specifications for the flight control system. As a result, the committee believes that the current TCA configuration does not adequately address APSE effects.
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From page 96... ...
Recommendation 5-1. The development of design tools and techniques for synthesizing and validating a highly integrated flight and propulsion control system and for properly addressing APSE effects on flight control and flight management systems should be established as a top-level research issue within the HSR Program during Phase II and the subsequent phases proposed by the committee.
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From page 97... ...
The system would provide the flight crew with "synthetic vision" equal to or better than the unaided human eye through all phases of flight, including approach, landing, and ground operations. Like the flight deck systems on other large commercial transports, HSCT flight deck systems will be highly reliable and multiply redundant.
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From page 98... ...
and could be included by industry in the design of a commercial HSCT. FIGURE 5-4 Artist's concept of one possible flight deck.
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From page 99... ...
That is, the detail depicted by the XVS displays must enable the flight crew to see other aircraft and airfield features just as well (or better) than they could by looking through the windows of a conventional flight deck.
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From page 100... ...
As a result, the display configuration on the TIES will require more than four projectors, which could make it more difficult to create a single, consistent display image. Flight Deck Program Challenges The XVS will have the potential to help make the HSCT safer than current or future subsonic aircraft by creating visual meteorological conditions for the flight crew regardless of actual weather conditions.
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From page 101... ...
101 l LU ~ <: ~ G o an En X An :C ~' C\l ~ Call t(L)
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From page 102... ...
The goal for the XVS is 99 percent; achieving this goal would constitute a significant safety improvement relative to conventionally equipped subsonic aircraft. Ground Operations Because the HSCT flight deck (and flight crew)
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From page 103... ...
Redundancy and Graceful Degradation of the External Visibility System The XVS will be the sole means of providing HSCT flight crews with forward visibility. Therefore, the XVS must be designed to operate reliably, with no catastrophic, total failures.
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From page 104... ...
To address flight deck system risk adequately, the preliminary flight tests planned during Phase II of the HSR Program should be supplemented by additional flight tests during the proposed technology maturation and advanced technology demonstration phases. These additional flight tests should use displays with resolution equal to the resolution needed for an operational HSCT.
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From page 105... ...
The HSR Program' s current noise goals are Stage 3-1 for sideline noise, Stage 3-5 for cutback noise, and Stage 3-1 for approach noise. Cutback noise is currently the limiting condition driving noise-reduction efforts.
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From page 106... ...
. Establish a certification issues program element in each of the key technical disciplines (viz., aerodynamics, structures and materials, flight deck, propulsion, and environmental impact)
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From page 107... ...
and the TIES aircraft to examine HSCT certification criteria for collision avoidance, ground operations, manipulation of control surfaces during takeoffs,9 and other areas related to certification of an HSCT flight deck and the XVS. However, it is not clear how future activities by the CICTs will relate to other HSR Program activities.
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From page 108... ...
Studies to date do not indicate that conceptual changes in the TCA design are required to meet operational needs of airlines, airports, or the air traffic control system. However, the committee believes that additional studies are needed to assess potential incompatibilities accurately, and the time, cost, and impact of corrective action.
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From page 109... ...
However, making changes to airport facilities (including taxiways) and air traffic control procedures, although technologically simple, may be difficult from a funding and environmental/community acceptance perspective.
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