j2 Classical


The evaluation and analysis of an aircraft design occurs in many stages. Producing the basic classical stability criteria and modes of motion data forms part of the complete aircraft evaluation process. By using j2 Classical, a fully integrated component of the j2 Universal Tool-Kit, there is no need to go to any another application to start looking at Linear Analyses and developing algorithms to establish modes of motion.

When linearising a full model, a typical process would start from an initial condition and linearise about that point. Since we have the results for our aircraft, trimmed over a range of configurations and flight conditions, this is where we will start.



j2 Classical will take the results of previous steady state analyses and linearise the aircraft about that point. At the same time it will calculate a state space set of matrices and all derivatives about the chosen point. From the state space system the eigenvalues and eigenvectors are established, and the subsequent modes of motion that these relate to. All this can be performed on the complete set of trim results in a matter of minutes. From these results we can then look at the stability characteristics.

From the full set of Eigenvalues for the complete flight envelope it is possible to establish any key areas of concern, then looking in more detail at the Eigenvalues, for Short Period say, at a given configuration. This means that trends can be found and evaluated.

With the pre-defined templates and charts, it is possible to evaluate characteristics against specific industry standards and requirements for the aircraft classification.

Even create user defined criteria and templates to look at things that are company specific.

All of this significant analytical work is completed in minutes and can be re-evaluated for every design change or refinement of the data model as more information becomes known about the aircraft.

Whether the user is working at Conceptual or Preliminary design stage or developing Certification procedures and test, the j2 Universal Tool-Kit with j2 Classical plug-in can be used throughout.


In using j2 Classical the analytical tasks that would normally take you man days and even man weeks to complete are reduced to man hours and the added benefit of not having to move data in and out of other software tools, with the resultant data transformation and error issues this can produce, can yield further quality improvement and additional time savings.