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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Neutron star moments of inertia

An approximation for the moment of inertia of a neutron star in terms of only its mass and radius is presented, and insight into it is obtained by examining the behavior of the relativistic structural equations. The approximation is accurate to approximately 10% for a variety of nuclear equations of state, for all except very low mass stars. It is combined with information about the neutron-star crust to obtain a simple expression (again in terms only of mass and radius) for the fractional moment of inertia of the crust.

Ravenhall, D. G.↗
NASA NTRS1974

Experimental determination of the principal moments of inertia of the Helios prototype spacecraft

The moment of inertia of the Helios Spacecraft about its spin axis was determined by use of a roll-fixture using two sets of crossed flexure pivots as elastic constraints. The test procedure entailed measurement of a system oscillation period with each of a set of added moment-of-inertia increments. The tare effect of the fixture was determined by a like process and was subtracted from the gross value to yield the spacecraft roll moment of inertia to an estimated accuracy of 0.2%. Lateral moments of inertia (i.e., about each of three axes normal to the spin axis) were determined by a gravity pendulum method that makes use of the fact that any physical pendulum has a minimum period of oscillation determined by a particular distance from the axis of rotation to the system center of gravity.

Gayman, W. H.↗
NASA NTRS1989

The moments of inertia of Mars

The mean moment of inertia of Mars is, at present, very poorly constrained. The generally accepted value of 0.365 M(R-squared) is obtained by assuming that the observed second degree gravity field can be decomposed into a hydrostatic oblate spheroid and a nonhydrostatic prolate spheroid with an equatorial axis of symmetry. An alternative decomposition is advocated in the present analysis. If the nonhydrostatic component is a maximally triaxial ellipsoid (intermediate moment exactly midway between greatest and least), the hydrostatic component is consistent with a mean moment of 0.345 M(R-squared). The plausibility of this decomposition is supported by statistical arguments and comparison with the earth, moon and Venus.

Bills, Bruce G.↗
NASA NTRS1947

Formulas for additional mass corrections to the moments of inertia of airplanes

Formulas are presented for the calculation of the additional mass corrections to the moments of inertia of airplanes. These formulas are of particular value in converting the virtual moments of inertia of airplanes or models experimentally determined in air to the true moments of inertia. A correlation of additional moments of inertia calculated by these formulas with experimental additional moments of inertia obtained from vacuum chamber tests of 40 spin-tunnel models indicates that formulas give satisfactory estimations of the additional moments of inertia.

MOMENTS OF INERTIA↗
NASA NTRS1936

Estimation of moments of inertia of airplanes from design data

A method of determining the moments of inertia of an airplane from design data pertaining to the weights and locations of the component parts is described. The computations required to ascertain the center-of-gravity position are incorporated with the calculations of moments of inertia. A complete set of data and calculations for a modern airplane is given to illustrate the procedure. From a comparison between calculated values and measured values it is believed that the moments of inertia can be estimated within 10 percent by the use of this method.

AIRPLANES - DESIGN↗
NASA NTRS1991

The earth's equatorial principal axes and moments of inertia

The earth's equatorial principal moments of inertia are given as A and B, where A is less than B, and the corresponding principal axes are given as a and b. Explicit formulas are derived for determining the orientation of a and b axes and the difference B - A using C(22) and S(22), the two gravitational harmonic coefficients of degree 2 and order 2. For the earth, the a axis lies along the (14.93 deg W, 165.07 deg E) diameter, and the b axis lies perpendicular to it along the (75.07 deg E, 104.93 deg W) diameter. The difference B - A is 7.260 x 10 to the -6th MR2. These quantities for other planets are contrasted, and geophysical implications are discussed.

Liu, H. S.↗
NASA NTRS1977

The calculation of the mass moment of inertia of a fluid in a rotating rectangular tank

This analysis calculated the mass moment of inertia of a nonviscous fluid in a slowly rotating rectangular tank. Given the dimensions of the tank in the x, y, and z coordinates, the axis of rotation, the percentage of the tank occupied by the fluid, and angle of rotation, an algorithm was written that could calculate the mass moment of inertia of the fluid. While not included in this paper, the change in the mass moment of inertia of the fluid could then be used to calculate the force exerted by the fluid on the container wall.

Source record↗
NASA NTRS1940

Measured moments of inertia of 32 airplanes

A compilation of the experimentally determined moments of inertia of 32 airplanes is presented. The measurements were obtained at the laboratories of the naca by means of a pendulum method. The airplanes tested are representative of several types of aircraft of gross weight less than 10,000 pounds. The results are presented in coefficient as well as in dimensional form. An elementary analysis of the data disclosed the possibility of grouping the results according to wing type of the airplane, as low-wing monoplanes, parasol and high-wing monoplanes, and biplanes. The data are shown to provide a convenient means of rapidly estimating the moments of inertia of other airplanes. A three view drawing of each of the 32 airplanes is included.

Gracey, William↗
NASA NTRS1922

The Effect of Longitudinal Moment of Inertia upon Dynamic Stability

Free flight tests were carried out to show whether the longitudinal oscillations of a standard S.E.5A airplane are noticeably affected if its longitudinal moment of inertia is increased. These oscillations were taken by means of a self-recording instrument, the airplane having first its ordinary moment of inertia and then one increased by 14 percent. The period of oscillation was slightly longer after the increase of the moment of inertia, but the damping was not affected. Presented here are test results from an investigation to determine the relative performance of a single-cylinder, high-speed, compression-ignition engine when using fuel injection valve nozzles with different numbers, sizes, and directions of round orifices. A spring loaded, automatic injection valve was used. It was centrally located at the top of a vertical disk-type combustion chamber formed between horizontally opposed inlet and exhaust valves of a 5-inch by 7-inch engine. A series of fuel injection valve nozzles with different arrangements of round orifices were tested, starting with orifices so small that impingement on the combustion chamber walls was impossible and increasing beyond the start of impingement. a :A table and curves are presented showing the performance of the engine with different nozzles. The test results are discussed, and some probable reasons given for the variation in performance with different nozzles on the basis of spray distribution.

MOMENTS OF INERTIA - ROYAL AIRCRAFT FACTORY S E 5A↗