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NACA-TN-1193
Effect of product of inertia on lateral stability
Year: 1947
Abstract: INTRODUCTION
Recent flight tests and tests in the Langley free-flight tunnel indicated a discrepancy between the observed and calculated conditions for dynamic lateral stability. It was suggested that the discrepancy might be the result of neglecting terms in the equations of motion involving the product of inertia.
The theoretical investigations of the lateral stability of airplanes undertaken in the past have for the most part neglected the effect of the inclination of the principal longitudinal axis of the airplane to the flight path on the oscillatory-stability boundary. (See reference 1 to 3) In the appendix of reference 1, Zimmerman mentions that the results of supplementary calculations indicated that to neglect the angularity of the principal axis to the flight path did not seriously affect the oscillatory-stability boundary in the normal-flight range and gave slightly conservative results. The results of reference 1, are based on lateral equations of motion from which the effect of the inclination of the principal axis to the flight path are omitted, namely, the terms including the product inertia.
For the range of airplane parameters investigated by Zimmerman, the product-of-inertia terms probably have a small stabilizing effect on the oscillatory-stability boundary. However, the effect of product of ineritia on the results of stability calculations covering the range of parameters of present-day airplanes designed for high-speed, high-altitude flight-tht is,high values of the relative-density factor u, a large increase in the effective dihedral parameter clβ caused by the use of swept-back wings, and the change in the mass distribution of the airplane – has not been investigated.
In the present investigation calculations were made to determine the effect of the product of inertia on the requirements for lateral stability. The results of the computations were plotted as a function of the firectional stability derivative clβ and the effective-dihedral parameter clβ
Recent flight tests and tests in the Langley free-flight tunnel indicated a discrepancy between the observed and calculated conditions for dynamic lateral stability. It was suggested that the discrepancy might be the result of neglecting terms in the equations of motion involving the product of inertia.
The theoretical investigations of the lateral stability of airplanes undertaken in the past have for the most part neglected the effect of the inclination of the principal longitudinal axis of the airplane to the flight path on the oscillatory-stability boundary. (See reference 1 to 3) In the appendix of reference 1, Zimmerman mentions that the results of supplementary calculations indicated that to neglect the angularity of the principal axis to the flight path did not seriously affect the oscillatory-stability boundary in the normal-flight range and gave slightly conservative results. The results of reference 1, are based on lateral equations of motion from which the effect of the inclination of the principal axis to the flight path are omitted, namely, the terms including the product inertia.
For the range of airplane parameters investigated by Zimmerman, the product-of-inertia terms probably have a small stabilizing effect on the oscillatory-stability boundary. However, the effect of product of ineritia on the results of stability calculations covering the range of parameters of present-day airplanes designed for high-speed, high-altitude flight-tht is,high values of the relative-density factor u, a large increase in the effective dihedral parameter clβ caused by the use of swept-back wings, and the change in the mass distribution of the airplane – has not been investigated.
In the present investigation calculations were made to determine the effect of the product of inertia on the requirements for lateral stability. The results of the computations were plotted as a function of the firectional stability derivative clβ and the effective-dihedral parameter clβ
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T17:18:27Z | |
| date available | 2017-09-04T17:18:27Z | |
| date copyright | 01/01/1947 | |
| date issued | 1947 | |
| identifier other | ZKYIYDAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std/handle/yse/141796 | |
| description abstract | INTRODUCTION Recent flight tests and tests in the Langley free-flight tunnel indicated a discrepancy between the observed and calculated conditions for dynamic lateral stability. It was suggested that the discrepancy might be the result of neglecting terms in the equations of motion involving the product of inertia. The theoretical investigations of the lateral stability of airplanes undertaken in the past have for the most part neglected the effect of the inclination of the principal longitudinal axis of the airplane to the flight path on the oscillatory-stability boundary. (See reference 1 to 3) In the appendix of reference 1, Zimmerman mentions that the results of supplementary calculations indicated that to neglect the angularity of the principal axis to the flight path did not seriously affect the oscillatory-stability boundary in the normal-flight range and gave slightly conservative results. The results of reference 1, are based on lateral equations of motion from which the effect of the inclination of the principal axis to the flight path are omitted, namely, the terms including the product inertia. For the range of airplane parameters investigated by Zimmerman, the product-of-inertia terms probably have a small stabilizing effect on the oscillatory-stability boundary. However, the effect of product of ineritia on the results of stability calculations covering the range of parameters of present-day airplanes designed for high-speed, high-altitude flight-tht is,high values of the relative-density factor u, a large increase in the effective dihedral parameter clβ caused by the use of swept-back wings, and the change in the mass distribution of the airplane – has not been investigated. In the present investigation calculations were made to determine the effect of the product of inertia on the requirements for lateral stability. The results of the computations were plotted as a function of the firectional stability derivative clβ and the effective-dihedral parameter clβ | |
| language | English | |
| title | NACA-TN-1193 | num |
| title | Effect of product of inertia on lateral stability | en |
| type | standard | |
| page | 18 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1947 | |
| contenttype | fulltext |