Many items not required for local soaring are needed for cross-country flights. Pilot comfort and physiology is even more important on cross-country flights since these flights often last longer than local flights. An adequate supply of drinking water is essential to avoid dehydration. Many pilots use the backpack drinking system with readily accessible hose and bite valve that is often used by bicyclists. This system is easily stowed beside the pilot, allowing frequent sips of water. A relief system also may be needed on longer flights. Cross-country flights can last up to 8 hours or more, so food of some kind is also a good idea.
Several items should be carried in case there is an off-field landing. (For more details, see Chapter 8, Abnormal and Emergency Procedures.) First, a system for securing the glider is necessary, as is a land-out kit for the pilot. The kit varies depending on the population density and climate of the soaring area. For instance, in the Great Basin in the United States, a safe landing site may be many miles from the nearest road or ranch house. Since weather is often hot and dry during the soaring season, extra water and food should be added items. Taking good walking shoes is a good idea as well. A cell phone may prove useful for landouts in areas with some telephone coverage. Some pilots elect to carry an Emergency Position Indicating Radio Beacon (EPIRB) in remote areas in case of mishap during an off-field landing.
Cross-country soaring requires some means of measuring distances to calculate glides to the next source of lift or the next suitable landing area. Distances can be measured using a sectional chart and navigational plotter with the appropriate scale, or by use of Global Positioning System (GPS). If GPS is used, a sectional and plotter should be carried as a backup. A plotter may be made of clear plastic with a straight edge on the bottom marked with nautical or statute miles for a sectional scale on one side and World Aeronautical Chart (WAC) scale on the other. On the top of the plotter is a protractor or semicircle with degrees marked for measuring course angles. A small reference index hole is located in the center of the semicircle. [Figure 11-2] Prior to taking off, it may be handy to prepare a plotter for the specific glider’s performance by applying some transparent tape over the plotter marked with altitudes versus range rings in still air. After a little use, the glider pilot should gain a perception of the glide angle most often evident in the conditions of the day.
Glide calculations must take into account any headwind or tailwind, as well as speeds to fly through varying sink rates as discussed in chapter 5. Tools range widely in their level of sophistication, but all are based on the performance polar for the particular glider. Most high-performance gliders usually have glide/navigation computers that automatically computer the glide ratio (L/D). The simplest glide aid is a table showing altitudes required for distance versus wind, which can be derived from the polar. To avoid a table with too many numbers, which could be confusing, some interpolation is often needed. Another option is a circular glide calculator as shown in Figure 11-3. This tool allows the pilot to read the altitude needed for any distance and can be set for various estimated headwinds and tailwinds. Circular glide calculators also make it easy to determine whether a pilot is actually achieving the desired glide, since heavy sink or a stronger-than- estimated headwind can cause a loss of more height with distance than was indicated by the calculator. For instance, the settings in Figure 11-3 indicate that for the estimated 10 knot headwind, 3,600 feet is required to glide 18 miles. After gliding 5 miles, there is still 2,600 feet. Note that this only gives the altitude required to make the glide.
The pilot can also use simple formulas to mentally compute an estimated L/D. One hundred feet per minute (fpm) is approximately 1 knot. To compute your glide ratio, take groundspeed divided by vertical speed as indicated on a vertical speed indicator (VSI) or variometer, then divide by 100 (just drop the zeros). If groundspeed is not available, use indicated airspeed, which will not yield as accurate a result as groundspeed. In this case, groundspeed or indicated airspeed is 60 knots. VSI shows 300 fpm down. Calculate the glide ratio.
Another method is to basically recompute a new L/D by utilizing this standard formula. Glide ratio, with respect to the air (GRA) or L/D, remains constant at a given airspeed. For example, your glider’s glide ratio, lift over drag (L/D) is 30 to 1 expressed as 30:1 at a speed of 50 knots. At 50 knots with an L/D of 30:1, a 10-knot tailwind results in an effective L/D of 36:1. [Figure 11-4]
In addition to a glide calculator, a MacCready ring on the variometer allows the pilot to easily read the speed to fly for different sink rates. MacCready rings are specific to the type of glider and are based on the glider performance polar. (See Chapter 4, Flight Instruments, for a description of the MacCready ring.) Accurately flying the correct speed in sinking air can extend the achieved glide considerably.
Many models of electronic glide calculators now exist. Often coupled with an electronic variometer, they display the altitude necessary for distance and wind as input by the pilot. In addition, many electronic glide calculators feature speed-to-fly functions that indicate whether the pilot should fly faster or slower. Most electronic speed-to-fly directors include audio indications, so the pilot can remain visually focused outside the cockpit. The pilot should have manual backups for electronic glide calculators and speed-to-fly directors in case of a low battery or other electronic system failure.
Other equipment may be needed to verify soaring performance to receive a Federation Aeronautique Internationale (FAI) badge or record flights. These include turn-point cameras, barographs, and GPS flight recorders. For complete descriptions of these items, as well as badge or record rules, check the Soaring Society of America website (www.ssa.org) for details.
Finally, a notepad or small leg-attached clipboard on which to make notes before and during the flight is often handy. Notes prior to flight could include weather information such as winds aloft forecasts or distance between turn points. In flight, noting takeoff and start time, as well as time around any turn points, is useful to gauge average speed around the course.