j2 Freedom
COMPLETE ENVELOPE ANALYSIS
J2 Freedom is the core calculation engine that allows the users to initialise the model to evaluate the complete aircraft over any initial condition. These can be classic steady state or unsteady investigations. The analyses can be used to fix the model at a specific point in space, or to solve for a given set of flight conditions. Any combination of states, surfaces and configurations can be set of to define the desired condition.
These initial conditions can be used to investigate any manoeuvre through the dynamic analyses from simple pre-defined pilot inputs to integrated controllers for a more “reactive” scenario.
Users are able to specify ranges of conditions and the software will identify all possible combinations. These can be run as batches and the results automatically saved for use at a different time, on a different model, or as initial conditions for subsequent analyses.
All results are fully configuration controlled and each is connected to models and analyses version numbers as well as users. This capability integrated into the j2 Universal Tool-Kit means that data can be recalled at a later date or cases automatically re-run following model updates.
The iterative design loop can be run seamlessly through an integrated environment, starting with multiple ideas and designs and rapidly enabling engineers to focus their efforts. This complete flight sciences capability can save up to 30% on aircraft design and development effort.
STATIC AND DYNAMIC ANALYSIS
The static analyses enables the user to create any initial condition for any aircraft project. The initial conditions are set by combining a Trim Rules. Trim rules contain a Target parameter and a Variable parameter. Typically the Variable parameter has a strong influence over the Target parameter although it may also effect other Targets when combined to create a Trim Condition.
Users can create rules that are specific to their aircraft project if they do not exist within the system. A range on each of the targets can be defined, and the software will work out all possible combinations to create a set of cases.
When running an analysis a comprehensive non-linear root solver will then be used to establish the values of the Variable Parameters that satisfy the desired Target Parameters value.
Historical solutions have relied on a series of fixed trim conditions that can be analysed. If these are to be expanded, the software needs to be modified to “hard code” the new scenario. Within the j2 Universal Tool-Kit, this unique approach to identifying initial conditions and trim solutions means that any scenario/condition can be evaluated. Furthermore, there is no need for models to conform to a fixed structure allowing for a much greater flexibility in building models.
With the pre-defined templates and charts, it is possible to evaluate characteristics against specific industry standards and requirements for the aircraft classification.
The dynamic analysis allows the user to build any manoeuvres to achieve the desired scenario. These can be combinations of model inputs, initial condition variations and gusts. These can be relative to the initial condition or as absolute values. Inputs and gusts can be entered as time histories or expressions. Using expressions enables feedback loops and integrators to be used to represent pilot reactions to specific flight conditions to take place.
Users can start with simple initial disturbances to excite primary modes of motion or develop complete flight test scenarios to enable the complete certification to take place.
KEY BENEFIT STATEMENT
In using j2 Freedom 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.