Aviator VTOL and Terrain Following

STK Premium (Air) or STK Enterprise
You can obtain the necessary licenses for this tutorial by contacting AGI Support at support@agi.com or 1-800-924-7244.

The results of the tutorial may vary depending on the user settings and data enabled (online operations, terrain server, dynamic Earth data, etc.). It is acceptable to have different results.

Capabilities covered

This lesson covers the following capabilities of the Ansys Systems Tool Kit® (STK®) digital mission engineering software:

  • STK Pro
  • Aviator

Problem statement

Aircrew mission planners need to determine how atmospheric phenomena and terrain will affect the performance of an airborne mission. Furthermore, they need analytical tools to model real-world aircraft performance, such as variations in airframe performance characteristics and mission requirements. You need to create a pre-brief for a checkride for a helicopter pilot who will fly search and rescue (SAR) missions in mountainous terrain. The checkride will consist of taking off from a helipad, navigating to three checkpoints, and returning back to the helipad for a landing. Part of the checkride will demonstrate the pilot's ability to fly above the terrain (terrain following) at 1,000 feet above ground level (AGL). You want to use the pre-brief to familiarize the pilot with the flight route and terrain features prior to the actual check ride.

Solution

Use a local terrain file for analysis and situational awareness together with the STK software's Aviator capability to model the flight path in context to aid in the mission pre-brief. Use the mission window to model the helicopter's performance characteristics and visualize its flight route from takeoff and add the waypoints and to factor in expected wind conditions. Finally, create a custom dynamic report that will display important flight data in the 3D Graphics window.

What you will learn

Upon completion of this tutorial, you will understand how to use the Aviator capability to do the following:

  • Model a VTOL aircraft
  • Configure a mission to use terrain following
  • Use the Reverse Point to Point Procedure Order tool
  • Create and use a Super Procedure
  • Create a dynamic Flight Profile By Time data display

Creating a new scenario

First, you must create a new scenario, then build from there.

  1. Launch the STK application ().
  2. Click Create a Scenario in the Welcome to STK dialog box.
  3. Enter the following in the New Scenario Wizard:
    4. Option Value
    Name Aviator_VTOL
    Location Default
    Start Default / Set the time to 19:00:00.000 UTCG
    Stop + 75 min
  4. Click OK when you finish.
  5. Click Save () when the scenario loads.

    6. The STK software creates a folder with the same name as your scenario for you.

  6. Verify the scenario name and location in the Save As window.
  7. Click Save.

Save () often during this tutorial!

Disabling streaming terrain

By default, the STK application connects to the Ansys Geospatial Data Cloud to distribute Earth terrain data for analysis and visualization. Turn off streaming terrain, as it is not required for your analysis.

  1. Right-click on Aviator_VTOL () in the Object Browser.
  2. Select Properties () in the shortcut menu.
  3. Select the Basic - Terrain page when the Properties Browser opens.
  4. Clear the Use terrain server for analysis check box in the Terrain Server panel.
  5. Click OK to confirm your change and to close the Properties Browser.

Adding analytical and visual terrain

An STK terrain inlay (.pdtt) file can be used both for analysis and for visualization in the 3D Graphics window. Load a preinstalled terrain inlay file for the area into your scenario using the Globe Manager.

  1. Bring the 3D Graphics window to the front.
  2. Click Globe Manager () on the 3D Graphics window's Globe Manager toolbar.
  3. Click Add Terrain/Imagery () on the Globe Manager Hierarchy toolbar when the Globe Manager opens.
  4. Select Add Terrain/Imagery... () in the drop-down menu.
  5. Click the Path ellipsis () when the Globe Manager: Open Terrain and Imagery Data dialog box opens.
  6. Browse to the install directory at C:\Program Files\STK_ODTK 13\Data\Resources\stktraining\imagery when the Browse For Folder dialog box opens.
  7. Click OK to confirm your selection and to close the Browse For Folder dialog box.
  8. Select the PtMugu_ChinaLake.pdtt check box.
  9. Click Add.
  10. Click Yes when prompted to use PtMugu_ChinaLake.pdtt for analysis.

Decluttering labels in the 3D Graphics window

Your analysis will take place in very mountainous terrain, which can obstruct object labels. Enable the Label Declutter option to separate the labels on objects that are in close proximity for better identification in small areas.

  1. Bring the 3D Graphics window to the front.
  2. Click Properties () on the 3D Graphics window's 3D Window Defaults toolbar.
  3. Select the Details page when the Properties Browser opens.
  4. Select the Enable check box in the Label Declutter panel.
  5. Click OK to confirm your selection and to close the Properties Browser.

Adding the flight route's waypoints

The check ride will consist of taking off from a helipad at Ridgecrest Regional Hospital and flying to three waypoints: one at the community of Dunmovin, one at Olancha Peak, and one at Mount Whitney itself, before returning to Ridgecrest by the same route.

Adding Dunmovin as a waypoint

Use Place objects, which model points of interest on the surface of a central body, for the waypoints. Start with Dunmovin, which is located in the Owens Valley between the Sierra Nevada to the west and the Coso Range to the east.

  1. Bring the Insert STK Objects tool () to the front.
  2. Select Place () in the Select An Object To Be Inserted list.
  3. Select Define Properties () in the Select An Object To Be Inserted list.
  4. Click Insert....
  5. Select the Basic - Position page when the Properties Browser opens.
  6. Enter the following in the Position panel:
    7. Option Value
    Latitude 36.0876 deg
    Longitude -117.963 deg
  7. Click OK to confirm your changes and to close the Properties Browser.
  8. Right-click on Place1 () in the Object Browser.
  9. Select Rename in the shortcut menu.
  10. Rename Place1 () Dunmovin.

Adding the second waypoint

Next, add Olancha Peak as the middlemost waypoint. Olancha Peak rises over 8,600 feet from the floor of the Owens Valley.

  1. Bring the Insert STK Objects tool () to the front.
  2. Insert a Place () object using the Define Properties () method.
  3. Select the Basic - Position page when the Properties Browser opens.
  4. Enter the following in the Position panel:
    5. Option Value
    Latitude 36.2665 deg
    Longitude -118.117 deg
  5. Click OK to confirm your changes and to close the Properties Browser.
  6. Rename Place2 () OlanchaPeak.

Adding the third waypoint

Mount Whitney, with an elevation of over 14,500 feet, is the tallest mountain in the contiguous United States. Add Mount Whitney as the last waypoint in the route.

  1. Bring the Insert STK Objects tool () to the front.
  2. Insert a Place () object using the Define Properties () method.
  3. Select the Basic - Position page when the Properties Browser opens.
  4. Enter the following in the Position panel:
    5. Option Value
    Latitude 36.5789 deg
    Longitude -118.291 deg
  5. Click OK to confirm your changes and to close the Properties Browser.
  6. Rename Place3 () MountWhitney.

Inserting an Aircraft object

Insert an Aircraft object which you'll use to model the helicopter and the training mission's flight route.

  1. Bring the Insert STK Objects tool () to the front.
  2. Insert an Aircraft () object using the Insert Default () method.
  3. Rename Aircraft1 () Checkride.

Using the Aviator capability

The STK software's Aviator capability provides an enhanced method for modeling aircraft — more accurate and more flexible than the standard Great Arc propagator. An aircraft using Aviator is defined by the type of aircraft and by the mission it performs. With Aviator, the aircraft's route is modeled by a sequence of curves parametrized by well-known aircraft performance characteristics, including cruise airspeed, climb rate, roll rate, and bank angle. Use Aviator to propagate the aircraft and optimize the STK application for use with the capability.

  1. Open Checkride's () Properties ().
  2. Select the Basic - Route page when the Properties Browser opens.
  3. Open the Propagator drop-down list.
  4. Select Aviator.
  5. Click Apply to confirm your selection and to keep the Properties Browser open.
  6. Read the information in the Flight Path Warning dialog box.

    7. Aviator performs best in the 3D Graphics window when the surface reference of the globe is set to MSL instead of the default reference of WGS84. Likewise, setting the animation mode to X Real Time allows for smoother animation and better data display performance.

  7. Click Optimize STK for Aviator to set the scenario globe reference to Mean Sea Level (MSL) and the Animation mode to X Real Time.
  8. Click OK to acknowledge the changes made to your scenario and to close the Flight Path Warning dialog box.

Selecting the helicopter's model

When you selected Aviator as the propagator, this transformed the Basic - Route page into the mission window. The mission window allows you to define the mission that the aircraft will perform. A mission encompasses the entire route traveled and all actions performed by the aircraft within a scenario; it describes not only where the aircraft goes, but how it goes there and what it does along the way. Defining the aircraft model is the first step in the process of defining a mission. An aircraft model defines the physical characteristics of the aircraft, the aircraft's configuration, and the modes of flight — performance models — that define how the aircraft flies in any given situation. Select a pre-built aircraft model and modify it to use for your helicopter.

  1. Click Select Aircraft () on the Initial Aircraft Setup toolbar.
  2. Right-click on Basic Helicopter () in the User Aircraft Models () tree hierarchy when the Select Aircraft dialog box opens.
  3. Select Duplicate in the shortcut menu.

    4. Basic Helicopter () is read only (). To make any modifications, you must duplicate the model and make changes to the copy.

  4. Right-click on Basic Helicopter Copy ().
  5. Select Rename in the shortcut menu.
  6. Rename Basic Helicopter Copy () Checkride.
  7. Click OK to confirm your selection and to close the Select Aircraft dialog box.
  8. Click Apply to confirm your changes and to keep the Properties Browser open.

Configuring the helicopter's performance models

Performance models are used to define the behavior of the aircraft in flight. By specifying performance models to use with each phase of the mission, you can vary the manner in which the aircraft performs based on the priorities of the mission. How an aircraft flies with Aviator depends on the performance model definitions and the specific procedures used to build a mission. The Aircraft Properties are used to define the settings and performance models of the aircraft.

Updating the Basic Acceleration performance model

Update the helicopter's Basic Acceleration performance model, which defines the basic turning, climb and descent transition, and attitude characteristics of the aircraft, to slightly increase its roll rate.

  1. Click Aircraft Properties () on the Initial Aircraft Setup toolbar.
  2. Select the Acceleration () Built-In Model () in the Performance Models tree when the Aircraft Properties dialog box opens.
  3. Enter 22 deg/sec in the Roll Rate field in the Altitude Transitions panel.
  4. Click Save to confirm your change and to keep the Aircraft Properties dialog box open.

Updating the Basic Climb performance model

Continue building the helicopter to specifications by updating the default Basic Climb performance model, which provides a constant climb rate and airspeed that you can specify.

  1. Select the Climb () Built-In Model () in the Performance Models tree.
  2. Enter 1600 ft/min in the Altitude Rate field.

    3. This is a constant rate at which the aircraft will climb once established in a steady climb.

  3. Click Save to confirm your change and to keep the Aircraft Properties dialog box open.

Updating the Basic Cruise performance model

The Basic Cruise performance model is comprised of a simple set of parameters that define the flight characteristics of the aircraft during level flight.

  1. Select the Cruise () Built-In Model () in the Performance Models tree.
  2. Enter 15000 ft in the Default Cruise Altitude field.
  3. Enter the following values in the Max Performance panel:
    4. Option Value
    Airspeed 131 nm/hr
    Fuel Flow 560 lb/hr

    These are a custom performance airspeed and fuel flow that you can use to model specific flight conditions.

  4. Click Save to confirm your changes and to keep the Aircraft Properties dialog box open.

Updating the VTOL performance model

Update the VTOL performance model for the helicopter.

  1. Select the VTOL () Basic Model () in the Performance Models tree.
  2. Enter 25 nm/hr in the Rate field in the Translation Maneuvers panel.

    3. This defines the rate at which the helicopter can translate while hovering. The Translation Maneuver Rate default is approximately nine (9) nm/hr. Because you will use a Mission Wind Model with a constant wind speed of 20 nm/hr and will be taking off into the wind, you need to compensate for the strong headwind when taking off.

  3. Click Save to confirm your change and to keep the Aircraft Properties dialog box open.

Creating a Terrain Follow performance model

You want to ensure the helicopter follows the terrain during its mission. To do this, you need to create a Terrain Follow performance model.

  1. Right-click in the Performance Models tree.
  2. Select Add New Model Type... in the shortcut menu.
  3. Select TerrainFollow in the Models list when the Add New Model Type dialog box opens.
  4. Click OK to confirm your selection and to close the Add New Model Type dialog box.
  5. Note that AGI TerrainFollow Model () is now available in the Performance Models tree.

Updating the Terrain Follow performance model

The Terrain Follow performance model defines the flight characteristics and maneuvering limits of the aircraft while performing a Terrain Following procedure. It functions similar to the Basic Cruise performance model, but applies only during Terrain Follow procedures. It also adds the MaxPitchAngle and TerrainWindow properties. The MaxPitchAngle limits the flight path angle between the peaks and valleys that are flown as a safety parameter (to avoid nose-low when flying near the ground) and utilizes a smoothing function. The TerrainWindow is a "look ahead" parameter that controls how the terrain is discretized when generating the flight profile; larger values give smoother flight paths.

  1. Select the TerrainFollow () AGI TerrainFollow Model () in the Performance Models tree.
  2. Note that the Airspeed and Fuel Flow values in the Max Performance panel are the same as the changes you made in the Cruise () Built-In Model ().
  3. Click Save to confirm your changes.
  4. Click Close to close the Aircraft Properties dialog box.
  5. Click Apply to confirm your changes and to keep the Properties Browser open.

Configuring the helicopter's general characteristics

You are modeling a high-altitude rescue helicopter. The Configuration is used to define the aircraft's fuel and payload.

Adjusting the helicopter's weight

Start by adjusting the helicopter's weight. The helicopter's empty weight is 3,951 pounds. Add 2,000 pounds to that total to account for crew and equipment.

  1. Click Configuration () on the Initial Aircraft Setup toolbar.
  2. Select the Basic tab when the Aircraft Configuration dialog box opens.

    3. The Basic tab is used to define the empty parameters of the aircraft, and displays the total values, based on the stations and fuel tanks defined for it.

  3. Set the following values for the helicopter's weights:
    4. Option Value
    Empty Weight 5951 lb
    Max Landing Weight 7903 lb

Adjusting the helicopter's fuel capacity

The Stations tab is used to define internal fuel tanks, stations, and external fuel tanks that are attached to the stations.

  1. Select the Stations tab.
  2. Select Internal Fuel () in the list of currently defined stations.
  3. Set the fuel state using the following values:
    4. Option Value
    Capacity 1530 lb
    Initial state 1500 lb

    The Capacity is how much fuel the helicopter can carry when full. This value cannot be less than the Initial state. Initial state is how much fuel is being loaded for the mission. This value cannot exceed the Capacity.

  4. Click Apply.
  5. Click OK to confirm your changes and to close the Aircraft Configuration dialog box.
  6. Click Apply to confirm your changes and to keep the Properties Browser open.

The changes made to the helicopter’s configuration are only saved to the current mission, not to the Aircraft Catalog. To alert you of this, the Configuration button now displays an exclamation mark () alerting you that your configuration is different from the catalog aircraft's default configuration.

Adjusting the Mission Wind Model

Use the Wind and Atmosphere Model tool to simulate wind and atmospheric conditions for the scenario, a mission, a specific procedure, or a group of selected procedures.

Updating the wind speed

For the purposes of this scenario, you will use a Constant Bearing / Speed wind model for your analysis, which creates a constant wind effect using the Wind Bearing and Wind Speed that you define.

  1. Click Mission Wind Model () on the Initial Aircraft Setup toolbar.
  2. Note that the Model Type defaults to Constant Bearing/Speed when the Mission_Acft (UI) wind/atmosphere model dialog box opens.
  3. Enter 20 nm/hr in the Wind Speed field.
  4. Keep the Wind Bearing set to 0 deg.
  5. Click OK to confirm your change and to close the Mission_Acft (UI) wind/atmosphere model dialog box.
  6. Click Apply to confirm your changes and to keep the Properties Browser open.

Plotting the crosswind in the mission profile

The mission profile can display a variety of data describing the mission. The default profile displays the aircraft's altitude relative to its downrange distance, but the graph can be customized to display any Flight Profile data provider. Update the mission profile to include the course crosswind, which is part of the Flight Profile By Down Range data provider. The course crosswind is the component of wind speed perpendicular to the ground track. Negative values imply wind is coming from the left. Flight data sampled using a constant downrange distance between grid points.

  1. Right-click in the Mission Profile.
  2. Select Profile Options/Properties... in the shortcut menu.
  3. Select the Secondary Y Axis check box when the Profile Options/Properties dialog box opens.
  4. Select Course Crosswind in the Secondary Y Axis list.
  5. Click OK to confirm your selection and to close the Profile Options/Properties dialog box.
  6. Note that Course Crosswind (nm/hr) is now labeling the axis on the right-hand side of the mission profile.
  7. Click Apply to confirm your changes and to keep the Properties Browser open.

Designing the Aviator mission with sites and procedures

Phases are the basic logical unit of a mission, and serve as containers for the procedures that define the aircraft's actions. Every mission must have at least one phase and can have as many phases as you desire. You can select a specific set of performance models to use with each phase, allowing you perform one mission with multiple performance characteristics. Your helicopter's mission will have a single phase.

Specifying the Phase performance model

In order to make the Terrain Follow procedure available, you need to link the Terrain Follow performance model from the Aviator catalog in the Phase Properties.

  1. Ensure Phase1 () is selected in mission list.

    2. The mission list in the mission window provides an overview of the mission by listing each of the mission phases and the procedures within them, in the order in which they will be executed.

  2. Click Phase Properties (), an ungrouped button next to the Procedures and Sites toolbar.
  3. Note the Model Type and Model Name columns when the Phase 1 Properties dialog box opens.

    4. The Phase Properties dialog box displays all of the performance model types in a tabular format. The Model Type field displays the performance model type, while the Model Name field displays the name of the specific performance model that is currently selected for the phase.

  4. Right-click on the TerrainFollow Model Type.
  5. Select Link to Catalog... in the shortcut menu.
  6. Select AGI TerrainFollow Model () when the Link to Catalog (TerrainFollow) dialog box opens.
  7. Click OK to confirm your selection and to close the Link to Catalog (TerrainFollow) dialog box.
  8. Note that the Source Field has been updated from n/a to Link to Catalog.

    9. The Source field displays the source of the performance model. Link to Catalog indicates that the performance model is stored in the Aviator Catalog Manager; changes made to the performance model within the catalog will propagate to this phase of the mission.

  9. Click OK to confirm your change and to close the Phase 1 Properties dialog box.
  10. Click Apply to confirm your changes and to keep the Properties Browser open.

Selecting the takeoff helipad site

Each phase is composed of procedures and sites. A site defines the location and the nature of the position at which the procedure takes place. In this case, the pilot will take off from a helipad at the Ridgecrest Regional Hospital in Ridgecrest, California. Model the helipad with a VTOL Point site, which is used for selecting VTOL procedures and has a specified altitude. When you select the VTOL Point site type, specific details of the site location must be defined manually. In this case, the information comes directly from the helipad's Airport Master Record with the Federal Aviation Administration (FAA).

  1. Click Insert Procedure After () on the Procedures and Sites toolbar.
  2. Select VTOL Point () in the Select Site Type list when the Site Properties dialog box opens.
  3. Enter RIDGECREST RGNL HOSPITAL HELIS H1 in the Name field.
  4. Enter the following geographic coordinates for the helipad:
    5. Option Value
    Latitude 35.640383 deg
    Longitude -117.672031 deg

Specifying the site's altitude

Because you are using a local terrain file, you need to specify the altitude of the procedure relative to the terrain.

  1. Open the Altitude drop-down list.
  2. Select AGL.
  3. Ensure the Altitude is specified as 0 ft.

This will set the site of the procedure as being on the surface of the terrain. If you leave MSL (mean seal level) selected for the altitude of the VTOL Point site, it will be located below the surface of the terrain.

Saving the VTOL Point to the Aviator Catalog Manager

The Aviator capability uses a catalog structure for the loading and saving of aircraft, airports, NAVAIDs, runways, VTOL points, and waypoints. Each of these mission elements has an associated catalog in the STK application. The Aviator Catalog Manager is a utility that allows you to view the contents of catalogs, create new items, copy or edit existing items, and search for specific items. Add RIDGECREST RGNL HOSPITAL HELIS H1 to the Aviator Catalog Manager; this will make it easier to use when you set up your landing procedure.

  1. Click Add To Catalog.
  2. Click OK to acknowledge the Add Successful warning.
  3. Click Next >.

In addition to catalog items installed with or created in the STK application, Aviator can read data from DAFIF and ARINC424 catalogs containing navigation information for runways, heliports (VTOL Points), and NAVAIDS. ARINC424 data files are the only valid data sources for navaid and airport sites. You can Download the latest Coded Instrument Flight Procedures (CIFP) dataset containing raw ARINC data from the FAA's website in a zipped file. You can then extract the FAACIFP18 data file contained therein and use it as the master data file for ARINC424 helipads from the Aviator Catalog Manager.

With this updated catalog loaded, you could insert Ridgecrest from the list of ARINC424 helipads with VTOL Point from Catalog site; in this scenario, however, because you are using a local terrain file for analysis and visualization, the VTOL Point would not be where you want it, since the ARINC424 catalog site has a fixed MSL altitude that you cannot change to be relative to AGL.

Selecting a Vertical Takeoff procedure

A Vertical Takeoff procedure launches an aircraft from a VTOL Point site directly up into the air. The procedure contains two control points: the procedure site, which is the point from which the aircraft is taking off, and a Hover Point, which is placed at a specified altitude above the procedure site.

  1. Select Vertical Takeoff () in the Select Procedure Type list.
  2. Enter 30 ft in the Altitude above point field.

    3. The helicopter needs to gain sufficient altitude to clear structures in its path before it transitions to forward flight.

  3. Enter 4 ft in the Altitude offset field.

    4. Because the flight path is calculated from the center point of the helicopter model, the offset above the ground level of the procedure site will account for the additional height provided by the helicopter's skids.

  4. Select the Heading The direction that the aircraft is pointing. into Wind check box in the Heading panel.
  5. Click Finish to confirm your changes and to close the Procedure Properties dialog box.
  6. Click Apply to confirm your changes and to keep the Properties Browser open.

Inserting an End of Previous Procedure site type

The end of the previous procedure can be used as a waypoint to define the site of the next procedure. In this instance, you want to transition to forward flight.

  1. Click Insert Procedure After () on the Procedures and Sites toolbar.
  2. Select End of Previous Procedure () in the Select Site Type list when the Site Properties dialog box opens.
  3. Click Next >.

Selecting a Transition to Forward Flight procedure

A Transition to Forward Flight procedure brings an aircraft from hover mode to forward flight mode. The aircraft will execute a translating maneuver if the final conditions of the previous procedure dictate any altitude, heading or translation rate. If there are any rates in heading, altitude or translation entering the procedure, the aircraft will immediately commence (or continue) the translation at the performance model translation rate while rotating its heading and continuing its altitude rate until established on the translation heading, at which point the aircraft will accelerate to its forward flight airspeed.

  1. Select Transition to Forward Flight () in the Select Procedure Type list.
  2. Select the Transition into Wind option in the Transition Course panel.

    3. This defines the course of the transition maneuver according to the wind direction.

  3. Click Finish to confirm your changes and to close the Procedure Properties dialog box.
  4. Click Apply to confirm your changes and to keep the Properties Browser open.

Proceeding to Dunmovin with an STK Static Object site type

After transitioning to forward flight, the helicopter will proceed to Dunmovin, which you added as a Place object earlier. Use an STK Static Object site, which is used to define a waypoint at the position of another, stationary, object within the scenario over time.

  1. Click Insert Procedure After () on the Procedures and Sites toolbar.
  2. Select STK Static Object () in the Select Site Type list when the Site Properties dialog box opens.
  3. Enter Dunmovin in the Name field.
  4. Select Dunmovin () in the Link To list.
  5. Click Next >.

Selecting a Basic Point to Point procedure

A Basic Point to Point procedure is a basic traverse between two waypoints. That is, it smoothly accelerates/decelerates under a constant climb/descent to arrive at the specified speed, altitude, and heading. Using basic point to point, the aircraft uses the Cruise performance model to determine speed and fuel flow. When altitude and push/pull radii can’t satisfy performance and flight path constraints specified by the user, extra maneuvers are inserted at the beginning of the procedure. The aircraft always achieves the specified speed and altitude, but may require extra maneuvers such as circle climbs to accomplish this.

  1. Select Basic Point to Point () in the Select Procedure Type list.
  2. Enter 5.00 in the Turn Factor field in the Enroute Options panel.

    3. A higher value increases the turn radius to minimize the bank angle required to complete the turn.

  3. Open the Enroute Cruise Airspeed drop-down list.
  4. Select Max Performance Airspeed.
  5. Click Finish to confirm your changes and to close the Procedure Properties dialog box.
  6. Click Apply to confirm your changes and to keep the Properties Browser open.

Proceeding to Olancha Peak with another STK Static Object site type

The helicopter will proceed to the next waypoint at Olancha peak.

  1. Click Insert Procedure After () on the Procedures and Sites toolbar.
  2. Select STK Static Object () in the Select Site Type list when the Site Properties dialog box opens.
  3. Enter OlanchaPeak in the Name field.
  4. Select OlanchaPeak () in the Link To list.
  5. Click Next >.

Selecting a Basic Point to Point procedure

Use another Basic Point to Point procedure for the second waypoint.

  1. Select Basic Point to Point () in the Select Procedure Type list.
  2. Enter 5.00 in the Turn Factor field in the Enroute Options panel.
  3. Open the Enroute Cruise Airspeed drop-down list.
  4. Select Max Performance Airspeed.
  5. Click Finish to confirm your changes and to close the Procedure Properties dialog box.
  6. Click Apply to confirm your changes and to keep the Properties Browser open.

Proceeding to Mount Whitney with another STK Static Object site type

Next, the helicopter will proceed to Mount Whitney, following the terrain to get there.

  1. Click Insert Procedure After () on the Procedures and Sites toolbar.
  2. Select STK Static Object () in the Select Site Type list when the Site Properties dialog box opens.
  3. Enter MountWhitney in the Name field.
  4. Select MountWhitney () in the Link To list.
  5. Click Next >.

Selecting a Terrain Following procedure

A Terrain Following procedure is a point to point procedure that applies terrain data to the aircraft's route, adjusting its altitude or flight path as needed to avoid intersecting with geographic features. Terrain following uses an algorithm guaranteed to avoid terrain impact. Terrain is discretized to a stairstep of maximum terrain height based on the TerrainWindow property (which is the time interval over which terrain points are sampled), then Bezier curve control points are specified so that no control point lies below the surface and the flight path angle limits are not violated. It is not constrained by the aircraft's ceiling. The process of terrain following begins at the end of the previous procedure and ends at the Terrain Following procedure's site. The Terrain Following procedure disregards the Climb and Descent models, using the Terrain Follow performance model's Max Pitch Angle and Speed values to define climbs and descents.

  1. Select Terrain Following () in the Select Procedure Type list.
  2. Enter 1000 ft in the AGL Altitude field.

    3. This sets the minimum AGL altitude that the aircraft will maintain during the Terrain Following procedure. The altitude of the control points is defined by the local terrain height plus this minimum terrain clearance altitude. The aircraft may fly higher if the parameters of the Terrain Follow performance model, the local terrain, and the specified ground path over the terrain require the aircraft to fly higher.

  3. Open the Terrain Following Airspeed drop-down list.
  4. Select Max Performance Airspeed.
  5. Click Finish to confirm your changes and to close the Procedure Properties dialog box.
  6. Click Apply to confirm your changes and to keep the Properties Browser open.

Using the Reverse Point to Point Procedure Order tool

After arriving at Mount Whitney, the pilot will turn and fly back to Ridgecrest to land. To save time and not rebuild the reverse course, you can use the Reverse Point to Point Procedure Order tool, which computes reverse versions of all of the currently selected point to point procedures and copies them to the clipboard. You can use this tool to automatically create a return flight path along the original outbound route and then paste it into your mission.

  1. Right-click on MountWhitney () in the mission list.
  2. Select Tools and Wizards in the shortcut menu.
  3. Select Reverse Point to Point Procedure Order ... in the Tools and Wizards submenu.
  4. Click OK to proceed when the Reverse Point to Point Procedures warning appears.

Returning to Ridgecrest with a Super Procedure

A Super Procedure is a collection of procedures. You can paste a group of procedures that have been saved to the clipboard, or load a Flight Procedure Collection file. The procedures before, after, or within a Super Procedure are not automatically validated by the Aviator capability. You must manually ensure that the sequence of procedures is valid. You can use a Super Procedure with a Super Procedure Site.

  1. Click Insert Procedure After () on the Procedures and Sites toolbar.
  2. Select Super Procedure () in the Select Site Type list when the Site Properties dialog box opens.
  3. Click Next >.
  4. Note Super Procedure () is automatically selected in the Select Procedure Type list.
  5. Click Load Procedures from Clipboard.
  6. Note that both OlanchaPeak () and Dunmovin () are now listed in the collection of procedures.
  7. Click Finish to confirm your changes and to close the Procedure Properties dialog box.
  8. Click Apply to confirm your changes and to keep the Properties Browser open.

Returning to Ridgecrest

After flying back to the waypoints at Olancha Peak and Dunmovin, the helicopter will return to land at Ridgecrest Regional Hospital. Because you saved the helipad to the catalog, this time, you can define helipad using a VTOL Point from Catalog site.

  1. Click Insert Procedure After () on the Procedures and Sites toolbar.
  2. Select VTOL Point from Catalog (). in the Select Site Type list when the Site Properties dialog box opens.
  3. Select RIDGECREST RGNL HOSPITAL HELIS H1 () under User VTOL Points () in the tree hierarchy.
  4. Click Next >.

Selecting a Transition to Hover procedure

Because an aircraft cannot perform a Vertical Landing procedure while in forward flight mode, you must first transition to hovering. A Transition to Hover procedure brings an aircraft from forward flight mode to hover mode.

  1. Select Transition to Hover () in the Select Procedure Type list.
  2. Select the AGL option in the Altitude panel.
  3. Enter 50 ft in the Altitude field.
  4. Select the Transition into Wind check box in the Transition Options panel.

    5. This will define the course of the helicopter according to the wind direction.

  5. Click Finish to confirm your changes and to close the Procedure Properties dialog box.
  6. Click Apply to confirm your changes and to keep the Properties Browser open.

Landing vertically back at Ridgecrest

Use the same VTOL Point to land back on the helipad.

  1. Click Insert Procedure After () on the Procedures and Sites toolbar.
  2. Select VTOL Point from Catalog (). in the Select Site Type list when the Site Properties dialog box opens.
  3. Select RIDGECREST RGNL HOSPITAL HELIS H1 () under User VTOL Points () in the tree hierarchy.
  4. Click Next >.

Selecting a Vertical Landing procedure

A Vertical Landing procedure brings an aircraft down from the air to a VTOL Point.

  1. Select Vertical Landing () in the Select Procedure Type list.
  2. Enter 4 ft in the Altitude offset field.
  3. Open the Mode drop-down list in the Heading panel.
  4. Select Heading into Wind.

    5. This sets the mode and ultimate final direction of the aircraft at the end of the procedure as into the wind.

  5. Click Finish to confirm your changes and to close the Procedure Properties dialog box.
  6. Click Apply to confirm your changes and to keep the Properties Browser open.

Viewing the mission profile

When you have finished building your mission, you can view your procedures and profile in the mission window.

  1. Select Phase1 () in mission list.

    2. This will display the entire flight route as bold lines rather than just the last procedure.

  2. Review the mission profile.

Completed Mission Profile

You can clearly see the period when the helicopter is performing terrain following as it approaches Mount Whitney. From the Course Crosswind data, which, as you recall, is the component of wind speed perpendicular to the ground track, you can view the periods when it changes course.

Determining the amount of fuel consumed

As you recall, you began the mission with 1,500 pounds of fuel on board. You can easily check how much fuel is remaining when you land by viewing the mission Profile Data. The Profile Data dialog box displays mission data at the point in the mission profile at which it is invoked. It displays all of the Flight Profile data providers, but can be sorted or filtered using the drop-down list at the top of the dialog box. You can view the profile data from any valid time in the mission by editing the Time field.

  1. Right-click on Vertical Landing () in the mission list.
  2. Select Profile Data at Final State... in the shortcut menu.
  3. Scroll down through the data providers when the Profile Data dialog box opens.
  4. Locate the Fuel Consumed data provider element and note the amount consumed.
  5. Close () the Profile Data window when finished.
  6. Click OK to confirm your changes and to close the Properties Browser.

Creating a dynamic data display

Add a custom dynamic data display to the 3D Graphics window that shows mission parameters for the flight.

Creating a new report style

Before you can create a dynamic data display for the flight, you must first create a custom report for it to reference. This report will enable you to view changes to selected elements over a period of time.

  1. Right-click on Checkride () in the Object Browser.
  2. Select Report & Graph Manager... () in the shortcut menu.
  3. Select the My Styles () folder, located in the tree in the Styles panel, when the Report & Graph Manager opens.
  4. Click Create new report style () on the Styles toolbar.
  5. Name the new report style () Mission Profile.
  6. Select the Enter key to confirm the report's name and to open its properties.

Selecting the report contents

Use elements of the Flight Profile By Time data provider to use for your dynamic data display.

  1. Select the Content page when the Properties Browser opens.
  2. Expand () the Flight Profile By Time () data provider when the Properties Browser opens.
  3. Insert () the following data provider elements into the Report Contents list in the following order:
    • Time ()
    • Downrange ()
    • Altitude ()
    • Altitude-AGL ()
    • Fuel Consumed ()
  4. Click OK to confirm your selections and to close the Properties Browser.
  5. Click Close to close the Report & Graph Manager.

If required, you can add any data providers of interest. Since you're going to use this report for display in the 3D Graphics window, it's a good idea to only insert a few parameters.

Adding a dynamic data display to the 3D Graphics window

Update the Aircraft object's 3D Graphics - Data Display properties to add your custom report as a dynamic data display.

  1. Open Checkride's () Properties ().
  2. Select the 3D Graphics - Data Display page when the Properties Browse opens.
  3. Click Add....
  4. Select Mission Profile in the Styles list when the Add a Data Display dialog box opens.
  5. Click OK to confirm your selection and to close the Add a Data Display dialog box.
  6. Click OK to confirm your changes and to close the Properties Browser.

Viewing the dynamic data display

Animate your scenario to see the mission profile information from your custom report in the 3D Graphics window.

  1. Right-click on Checkride () in the Object Browser.
  2. Select Zoom To in the shortcut menu.
  3. Use your mouse to get a good view of the helicopter.
  4. Click Start () on the Animation toolbar.
  5. Watch as the helicopter takes off and flies its route over to Mount Whitney, following the terrain as it approaches the peak.

    6. Mission profile dynamic Data Display

    You can increase () the X Real Time Multiplier as needed to speed up the animation.

  6. Click Reset () when finished.

Saving your work

Clean up your workspace and close out your scenario.

  1. Close all open reports, tools, and properties.
  2. Save () your work.
  3. Close the scenario when finished.

Summary

You began the scenario by turning off streaming terrain and loading a local terrain file for visualization and analysis. You then use the Aviator capability to model and configure a basic helicopter and its performance models to enable terrain following as well as configuring the expected wind conditions. Using a combination of VTOL sites and waypoints, you modeled the helicopter's flight route from takeoff at a helipad, which you added to the Aviator Catalog Manager, to a procedure where the helicopter performed terrain following. Using the Reverse Point to Point Procedure Order tool and a Super Procedure, you then modeled the return flight and landed back at the helipad. Finally, you examined the mission profile and created a dynamic data display using a custom report.

On your own

The STK software's Aviator Pro capability allows you to model the performance characteristics of rotorcraft as a distinct type of aircraft from a fixed wing aircraft. With this capability, you can create a rotorcraft model in the User Rotorcraft Models catalog of the Aviator catalog interface or catalog manager. You can learn more in the Quadcopter Design and Performance Analysis Over Terrain tutorial. You can also use Dynamic Control procedures with rotorcraft using a Dynamic Control Helicopter Acceleration model.