FliP is a tool for skydiving, specifically for planning the landing pattern.
You can use it here: https://flip.mustelinae.net/
This is just a tool and comes with NO GUARANTEES. If you use it, you MUST CRITICALLY evaluate the information it provides. Please use common sense and DO NOT trust it blindly. Please read the rest of the document and make sure you understand how it works and what the limitations are.
FliP models a landing pattern and optionally a manoeuvre (i.e. turn to final), including the effects of wind. It is meant to be a versatile tool for planning and exploration, so there are many adjustable parameters.
The manouvre can be described by the offset, altitude, and time (as can be extracted by gSwoop for example), or a GPS grack recorded with FlySight directly.
We usually plan our pattern manually based on 2 or 3 points in the pattern, approximate glide ratio, and a rough estimation of the winds. The problems with this approach are:
- It's a laborious process if you do it in detail.
- It uses only 2-3 points, and doesn't take into account how we fly e.g. the turn to base or the manoeuvre itself.
- It's hard to account for wind at different altitudes.
FliP solves these problems, but there are limitations and disadvantages:
- The wind adjustments are only as good as the wind forecast.
- It requires a sample FlySight file, ideally recorded in very light wind conditions.
FliP is designed to be used in conjunction with FlySight/FlySight Viewer, gSwoop, WindsAloft, etc and not to replace any of them.
Adjust the paraters of your landing pattern under the Pattern tab in the navigation menu on the left. The pattern is shown on the map as a green line.
Adjust the manoeuvre settings under the Manoeuvre tab in the navigation menu on the left. The manoeuvre is shown on the map as a red line.
You can enter the offset, altitude and time manually, use one of the built-in sample GPS tracks, or import your own GPS track.
To use FliP the most effectively for your planning you'll need to load your own FlySight track. Make sure it contains only your manoeuvre by selecting the portion that you want in FlySight Viewer and using the "Export Track" feature. It's best to trim the file so it stops at the time of plane out, and does not include the level flight over the ground. You can re-position to account for conditions manually. Once a track has been loaded, and optionally adjusted for wind, it can be saved locally under Manoeuvre -> My Tracks.
The location and precice position can be selected under the Target tab in the navigation menu on the left.
The "Set Target" and "Set Target And Heading" buttons can be used to select a location by clicking on the map. When setting both the target and direction, the first click will set the taget, and the second click will set the direction. Note that the direction is reversed, think of it as building your pattern from the ground up.
To quickly change to a different location on the map, you can either select one of the built-in dropzones from the list, of search from the Search tab. Once a target and direction have been selected, you can save them for easy access under My Locations.
You can adjust the wind settings under the Wind tab in the navigation menu on the left. You can just add wind at altitude 0, which will apply for all altitudes, or add more rows to specify different winds at different altitudes.
You can use the Fetch Forecast button to fetch the current forecast for the current location. When winds are loaded this way changing is disabled to
prevent accidental change; use the Unlock button if you need to make adjustments. The source of the forecast (either WindsAloft or OpenMeteo) can be selected
under the Settings tab.
When wind is added, the resulting path is shown as a solid line. The original track, prior the wind adjustment, is shown as a dashed line. The original track can be hidden with a setting under the Settings tab.
All operations that FliP applies to a track are centered around the final point. Because of that correct trimming of the file is essential to get meaningful results.
Repositioning is straightforward, but there are some subtleties when adding wind.
FliP ignores the absolute value of the elevation contained in the FlySight file. It assumes that the final point is at altitude 0, and all other points are relative to it.
The altitude specified for the wind is in feet AGL.
Wind is applied starting from the final point (which is kept in place). Each subsequent point is offset from the previous point based on:
- Its relative position to the previous point.
- The wind at the given altitude (the altitude of the first of the two points).
- The time difference between the two points.
This means we assume the wind affects us instantaneously (we have zero inertia). This is not realistic, but we make that assumption while planning anyway. Presumably if the wind shear is strong enough to make a practical difference we shouldn't be flying canopies :)
FliP DOES NOT correct for the elevation of the landing zone or density altitude in any way.
If your track was captured in known, light wind conditions, you can use FliP to cancel out the wind and get a cleaner sample. To do this load your track, then apply wind as necessary, then export the track.
No. My primary motivation for creating FliP is to use it myself for canopy piloting training, but I'm also using it with my students to plan straight-in landings.
It's my years long setup for a joke. When I have the time to build a Flocking Planner you'll be able to FliP/FloP between the two.
FliP is open-source, licensed under the Apache 2.0 license. It was created by Boris Grozev.
See the BUILD.md file for how to develop or build the application.