Choosing the Right Gimbal Balance Machine

December 28, 2020

Choosing the Right Gimbal Balance Machine The two primary factors affecting selection of a Space Electronics Gimbal Balance Machine are weight of the gimbal and its unbalance tolerance. Maximum gimbal weight.   The machine must accommodate the maximum weight and size of the gimbals to be balanced. However, it should be no larger than necessary since large […]

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Using a Spherical Air Bearing to Simulate Weightlessness

It is important to test the attitude control systems on satellites before they are launched in space. Traditionally this has been done by dropping the satellite, and firing the thrusters before the satellite makes a soft landing in a net. This method only allows a few seconds of testing and does not lend itself to […]

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Center of Gravity Definition

Factors Affecting Center of Gravity What is Center of Gravity (CG)? The center of gravity (CG) location is the average location of all the weight of an object. The center of gravity is the balance point of an object, also expressed as the point where all the mass appears to be located. How to Calculate […]

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Homemade Center of Gravity Instrument

Avoid the Pitfalls of Homemade Center of Gravity Instruments Making a center of gravity instrument does not seem insurmountable. Homemade solutions such as attaching a plate to 3 or 4 load cells can be done quite easily and at a seemingly low cost. But… – What is the REAL cost? – What accuracy will you […]

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Why Measure Moment of Inertia

Calculation vs Measurement The MOI of simple objects can be calculated fairly accurately using well-known formulas. To calculate the MOI for more complicated objects, you would need to model the object as a collection of simple shapes, calculate the individual MOI’s for each, and add the MOI values to obtain an aggregate value. However, when […]

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Principle of Operation of an MOI Instrument

Other Industries - Golf Clubs

The moment of inertia of any object can be measured through its CG by hanging the object from a wire, twisting it slightly to initiate oscillation, and timing the period of oscillation. However, anyone who has ever tried this finds that the object swings from side to side and bounces up and down rather than […]

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Torsion Pendulum Theory

Consider the torsion pendulum of Figure 1 consisting of a disk of mass moment of inertia I lb-in-sec2, restrained in rotation by a wire of torsional stiffness K in-lb/radian. If the disk is turned an initial angle and sharply released, it will oscillate with damped harmonic motion as shown in Figure 2. The period of […]

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