FlightMechanic is an application for the Apple iPhone 3GSM family that replaces many components of the popular Pratt & Whitney aerospace handbook, including a standard atmosphere model, airspeed calculations, and Rankine-Hugoniot relationships (Mach tables).

One of three screens available is the atmosphere table screen. The user can select and enter a value into any of the outlined fields, and the app will attempt to match that condition anywhere in the standard atmosphere table. The app responds by showing atmospheric properties at this altitude for the U.S. Standard Atmosphere, 1976, in English Units.

When the user enters a value for which there is no unique solution, such as a temperature or speed of sound (at certain values for these parameters, there are several possible altitudes that have the same temperature or speed of sound), the closest solution is located and a warning message, “Unique solution not found,” appears.

The second screen available in the app is the Airspeed Screen. This screen attempts to match two properties by varying the other parameters. Values for altitude and Mach number can be entered, and the resulting dynamic pressure, true airspeed, equivalent airspeed, calibrated airspeed, and Reynolds number are shown.

The final screen is the shock properties screen that implements the Rankine-Hugoniot relationships for a given Mach number. The user provides a Mach number, and the app shows the resulting temperature and pressure ratios behind the shock, as well as the shock wave angle (Mach angle).

This application is useful during technical meetings at which various flight operations may be discussed. Flight conditions at a particular test point can be quickly determined, for example, to find an altitude with a desired specific Reynolds number and dynamic pressure.

This work was done by Bruce Jackson of Langley Research Center. LAR-17924-1

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