GPS Map 76S
I use the Garmin 76S together and a Flytec 4030 Race variometer, both mounted in a Flytec racing pod.
These two instruments are capable of working together to provide info for cross country racing. For instance, they can tell you when you to go on final glide to goal and how far over goal you'll be when you arrive. I think they do this using wind direction and speed, average climb rate, polars for your glider, altitude, groundspeed, and distance to goal. However, I have not leearned how to use this function yet.
The 76S is a bit larger than a handheld calculator. The lower half is occupied by a black & white screen, while the upper half has the contol buttons. You can toggle through various screens:
Each screen can be customized to show the data you desire: time, groundspeed, and tons of other data.
There are two basic ways to use the GPS: 1. free flight cross country, and 2. cross country to a predetermined point or series of points that make a route.
For free flight cross country, I would use the map screen. The map screen shows roads, bodies of water, airports, etc. This helps you decide the path you would like to follow and helps identify objects the you may not be able to identify by sight. It also allows you to communicate your position to your driver if you have a radio.
Also, you can "mark" your startng point before you launch. This way, the GPS cna tell you how far you are from your starting point. If you also enter your starting point as the "goto" point, then you can use the compass to guide you back to the starting point. This is helpful in flatland flying where all the terrain looks the same and you've been turning circles and have gotten disoriented, you can quickly see which direction the LZ is.
For cross country to a predetermined point or series of points that make a "route", you have "waypoints" entered into your GPS. Before you launch, you select the point or create the route that you desire, or that has been assigned by the task committee in a competition.
When you activate the route, you use the compass to guide you to the first waypoint in your route. The other info I like in my compass screen is: distance remaining, groundspeed, and time.
You may also wish to toggle to the map screen to see if you are tracking on course. If there's a crosswind, you may notice that while your glider is pointed at the waypoint, you are being blown of course, thereby converting your actual path from a straight line to an arc. This will add distance and time to your flight, which can put you behind the other pilots in a competition.
After you land, you can toggle to the screen that shows your GPS coordiates so you can tell your driver, who can then program the retrieve vehicle GPS to go to where you are.
I just started using a GPS and flying cross country earlier this year (2008), so my knowledge is just enought to allow me to get by. Some pilots have mastered the use of their instuments, allowing them to make better decisions and fly farther and faster. This is a whole different interesting area of hang gliding for pilots to explore and learn.
I hope my brief and simple summary has helped anyone who may be interested to understand how a GPS is used for cross country hang gliding.