A note on the weight vs dynamic stability relations of subsonic airplanes.

Crosswind gusts can easily disturb the attitude of a small fixed-wing aircraft, potentially causing a serious accident during landing or take-off operations. An airplane with a high tolerance to crosswind gusts owing to quite small C l and C n values, called a Quasi-Neutral Dihedral-effect and Directional-stability (QNDD) airplane, was previously proposed. Although the design of a QNDD airplane is more practical than that of a Neutral Dihedral-effect and Directional-stability (NDD) airplane, a QNDD airplane's robustness to errors in C l and C n should be comparatively higher. In the present study, the QNDD airplane's robustness is optimized using Sequential Least-Squares Quadratic Programming (SLSQP). The optimized QNDD airplane has a unique configuration: a highly deflected swept-forward main wing. It is confirmed that the optimized design is much more robust than the original. To evaluate the performance of the optimized QNDD airplane, airplane plunging into a discrete crosswind gust is numerically simulated, and the results confirm that the airplane's change in attitude is still quite small compared with that of a conventional airplane.

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“…The values of C l and C n of the GA airplane are regarded as appropriate because they are similar to the ranges of conventional airplanes. 23)…”

Section: General Aviation Airplanementioning

confidence: 99%

Optimization of High-Crosswind-Tolerant Airplane Based on Double-Hinged-Wing and No-Vertical-Tail Configuration

Watanabe

Sunada

Yamaguchi

2023

Trans. Japan Soc. Aero. S Sci.

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“…Its detailed morphological values are indicated in Kato and Karasawa. 3) Added mass and added moment inertia, which were considered in the Mayfly analysis, can be ignored both on Earth and Mars. The flight velocity, Mach number and Reynolds number on Earth and Mars are shown in Table 8.…”

Section: Analysis Of a Meter-sized Airplanementioning

confidence: 99%

“…The stability derivatives on Earth are reported in Kato and Karasawa. 3) Those on Mars were calculated using the relations in Table 2, and the values on Earth reported in Kato and Karasawa. 3) Comparisons between the values of stability Table 9.…”

Section: Analysis Of a Meter-sized Airplanementioning

confidence: 99%

Flight Stability of an Airplane on Mars

Tajima

Sunada

Tokutake

et al. 2011

Trans. Japan Soc. Aero. S Sci.

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We compared the flight stability of an airplane on Mars and on Earth. Two kinds of airplanes were used in our analysis: a centimeter-sized indoor airplane with a very thin and light main wing, and a meter-sized airplane flying outdoors. Our comparisons show the following. (1) A longer period is required to damp or diverge disturbances on Mars than on Earth.(2) On Mars, the added mass and added moment of inertia can be ignored for a light wing, whereas the added mass and added moment of inertia cannot be ignored on Earth.(3) The natural circular frequencies in the short period, the phugoid, and the dutch roll modes are smaller on Mars than on Earth. The reduced frequencies, based on the natural circular frequencies on Mars, are smaller than those on Earth. The smaller reduced frequencies and the smaller added mass and added moment of inertia imply that the significance of unsteady aerodynamic force due to fuselage motion is lower on Mars than that on Earth.

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A note on the weight vs dynamic stability relations of subsonic airplanes.

Cited by 2 publications

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Optimization of High-Crosswind-Tolerant Airplane Based on Double-Hinged-Wing and No-Vertical-Tail Configuration

Optimization of High-Crosswind-Tolerant Airplane Based on Double-Hinged-Wing and No-Vertical-Tail Configuration

Flight Stability of an Airplane on Mars

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