WEIGHING B747-400 NOSE UP TO DETERMINE THE VERTICAL CENTER OF GRAVITY

摘要

The report describes in detail the test carried out at Israel Aerospace Industries (IAI) Jan 2006 to determine the vertical center of gravity of the Boeing 747-400 airplane. The Boeing 747-400 airplane underwent a conversion to an all cargo aircraft at IAI. IAI was therefore required to substantiate the conversion modifications for an airplane of another manufacturer. The vertical center of gravity is one of the parameters required in the analysis for the aircraft loads and dynamics, control and stability, ground loads, dynamic braking, and loadability. Essentially the method in the test was to weigh the airplane in two different airplane attitudes. The first weighing was performed with the aircraft in level attitude. Then the aircraft was lifted at the nose wheel and weighed again in the nose up position. The report includes full details of the setup (including photos), actual test results, computations and evaluation of the tolerances. A derivation to in service cargo configuration is included. The results obtained were considered to be very satisfactory. It is our hope that this report will be of practical help to anyone who wishes to carry out a similar test on a large airplane.