Use the Time / Fuel Ruler tool, which is a plugin for STK's Aviator capability, to estimate the time and fuel required for an Aviator aircraft to traverse a distance that you measure in the 3D graphics window.
Aircraft
Select the aircraft object that you want to use as the subject of your measurements. The aircraft must be using the Aviator propagator and must have at least one procedure defined in its mission. Select Start measuring from current position to use the final state of the selected aircraft as the first point that you will begin measuring from; otherwise, the first point that you click in the 3D window will be used as the measuring starting point.
Altitude
Select the altitude setting that you want to use for the calculations - Current Altitude or Default Cruise Altitude. The actual altitude of the setting that you have chosen is displayed beneath the drop-down menu. The selected altitude will be applied constantly.
Airspeed
Select the airspeed setting that you want to use for the calculations - Current Airspeed, Max Range Airspeed, or Max Performance Airspeed. The actual airspeed of the setting that you have selected is displayed beneath the drop-down menu. You can select an airspeed reference (Mach The ratio of the aircraft's speed and the speed of sound at the aircraft's altitude, with local atmospheric conditions., EAS Equivalent Airspeed: the airspeed at sea level (International Standard Atmosphere) at which the dynamic pressure is equal to the dynamic pressure at the aircraft's current true airspeed and altitude., CAS Calibrated Airspeed: the speed reported by the airspeed indicator, corrected for position and instrument error., TAS True Airspeed: the speed that the aircraft is moving relative to the airmass that it is flying in.) from the drop-down menu. The selected airspeed will be applied constantly.
Measuring in the 3D Graphics Window
To begin measuring distances, click Start Measuring and then click on the first point that you want to measure in the 3D graphics window. The Time Required, Distance, Fuel Required, and Fuel State fields in the Time / Fuel Ruler window will update to display the measurements that the tool has calculated for the aircraft to reach that point. You can continue to click in the 3D graphics window to add waypoints and extend the measured route; the data fields in the Time / Fuel Ruler will update at each point that you select. If the aircraft does not have enough fuel to reach a point that you have just clicked, that leg of the route will be displayed in red. If you want to stop measuring, right-click anywhere or left-click outside of the 3D graphics window.
Range Ring Report
In addition to measuring routes in the 3D graphics window, you can run the Flight Range Ring By Time report to generate a list of points that the aircraft can reach from a specified position. A pre-data panel for the report allows you to specify the time (which will be used to determine the aircraft's position), the amount of remaining fuel that you want to define as maximum range, and the distance along the ring between maximum range points.