Flight mechanics data from a handling qualities

This preview shows 8 out of 10 pages.

Flight Mechanics Data From a handling qualities viewpoint, pilot workload and task performance are important ingredients in assessing the pilot acceptability of flying the multi-segment, noise- abatement, decelerating approach profiles. This aspect of the issue related to the feasibility of achieving noise abatement through the use of specific flight procedures has been addressed previously in some detail in refer- ence2. Here, other aspects of the issue, which are related to noise-certification flight procedures, effects of deceler- ating approach flight on BVI noise, and the importance of measuring, in flight, the tip-path-plane angle of attack of the main rotor will now be discussed. Flight Technical Errors The tracking performance was found to be generally within the flight performance window required for noise certification testing. Figures 9(a)–9(c) show some examples of repeated runs of the 6 deg decelerating approaches at 80 knots, Quiet, and HAI-Light approaches. These flight trajectories are plotted as altitude vs. horizontal distance from the helipad. It is seen that the altitude tracking errors are somewhat better for the 6deg decelerating approaches than for the other two set of approaches. Nevertheless, they are all within the perfor- mance window called for in noise certification, i.e., ± 30 ft (ref. 8). This can be seen from figures 10(a) and 10(b), which show the mean and standard deviation of all the approaches from run #4 to #23 for two windows. Win- dow1, shown in figure 10(a), covers the horizontal range of ± 1000 ft from the center mics, while window2, shown in figure 10(b), extends the horizontal coverage to ± 2000ft. These ranges, which both extend beyond the 10dB-down points from the peak noise at the center mics (as will be shown later), were chosen to demonstrate the consistency of the tracking performance. In terms of time duration, these two windows represented approximately 20, and 40sec of flight time. Rate of Descent vs. Airspeed It is important to examine the rate-of-descent tracking performance, since the design of the noise-abatement approach profiles originated in the plane of rate of descent vs. airspeed. The test results indicate that the rate-of- descent tracking performance was less than desirable as shown in figures 11(a) and 11(b) for two sample noise- abatement approach runs. The rate of descent errors of the four-segment Quiet profile, figure 10(a), were large, espe- cially in the first descent segment. Pilots commented on the difficulty with which this profile was flown with or
Image of page 8

Subscribe to view the full document.

7 without the collective flight director, which had been designed for a constant speed approach as discussed ear- lier. Use of a properly designed 3-cue flight director sys- tem, especially with the third cue collective-commands properly tuned to the flight dynamics of the decelerating approach of the RASCAL helicopter, should improve the rate-of-descent tracking performance.
Image of page 9
Image of page 10
You've reached the end of this preview.
  • Spring '10
  • frando
  • Aerodynamics, Aviation terminology, BVI, Instrument approach, Helicopter rotor, acoustic data

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern