Many factors affect flight planning and aircraft operation, including aircraft weight, weather, and runway surface. The recommended flight parameters listed below are intended to give approximations for flights at maximum takeoff or landing weight on a day with International Standard Atmosphere (ISA) conditions.
Important: These instructions are intended for use with Flight Simulator only and are no substitute for using the actual aircraft manual for real-world flight.
Note: As with all of the Flight Simulator aircraft, the V-speeds and checklists are located on the Kneeboard. To access the Kneeboard while flying, press SHIFT+F10, or on the Aircraft menu, click Kneeboard.
Note: All speeds provided in the Flight Notes are indicated airspeeds. If you're using these speeds as reference, be sure that you select Display Indicated Airspeed in the Realism Settings dialog box. Speeds listed in the specifications table are shown as true airspeeds.
Required Runway Length
Note: The length required for both takeoff and landing is a result of a number of factors, including aircraft weight, altitude, headwind, use of flaps, and ambient temperature. The figures here are conservative and assume:
Weight: Maximum gross weight
Altitude: Sea level
Wind: No headwind
Runway: Hard surface
The DG–808S is a sailplane and has no engine, so it descends unless you fly into an area of rising air. By finding air that is rising as fast as (or faster than) the sailplane is descending, you can maintain (or gain) altitude. Finding rising air is challenging, and the duration of your flight depends on your skill.
You can find thermals by flying in hot, dry areas. Read the Soaring article to learn more about using thermals and ridge lift.
Flaps and water ballast
On the DG–808S, available flap settings are from -9 to +18 degrees. See the Kneeboard for flap operating speeds.
The DG–808S has water ballast tanks in the wings, tail fin, and fuselage.
Run through the Before Takeoff checklist on the Kneeboard. Use the tow plane or the Slew feature to raise the aircraft to altitude.
To get towed aloft by the tow plane
To Slew to altitude
When being towed aloft by the tow plane, set the wing flaps to +13 degrees and hold the joystick or yoke forward. At 80 km/h (43 knots), gently ease back on the joystick. Normal towing speed is 120-130 km/h (65-70 knots), but for a cross-country tow, 190 km/h (103 knots) is safe. At the higher tow speed, the flaps should be at a negative setting.
When you reach 3,000 to 4,000 feet, deactivate slewing or release from the tow plane. Use the very effective Schempp-Hirth airbrakes (press the SLASH [ / ] key, or drag the airbrake lever) to control speed while recovering to soaring flight. Lower the airbrakes once you level off (press the SLASH [ / ] key, or drag the spoiler lever).
Alternatively, you can set your altitude and airspeed in the Map. On the World menu, click Map, and then enter the altitude and airspeed in the appropriate boxes. Because you entered an airspeed, the aircraft won't pitch down when you turn off Slew mode and you won't need to use the airbrakes
The initial climb in the DG–808S is determined by the tow plane speed. Cruise climb requires that you fly in an area of rising air. You must fly the sailplane in an area where the ground surface, heated by the sun, creates thermals. Learning how to take advantage of rising air to remain aloft or to climb can be one of the most enjoyable aspects of flying the sailplane. Pay attention to your variometer and altimeter when searching for areas of rising air.
Using the variometer
An instrument called the variometer helps you know when you're in rising air and how strong the lift is. Unlike a vertical speed indicator in a powered aircraft, which indicates the vertical speed of the aircraft, a compensated variometer indicates the vertical speed of the air through which a glider is moving.
To use the variometer, fly into a thermal or into ridge lift until the variometer's audio signal begins a series of beeps that rise in pitch. This indicates you're flying in rising air. Watch the variometer rate gauge to see the rate at which the air is rising or falling.
When the audio tone lowers in pitch and stops beeping, you know you're losing lift and should seek another area of rising air if you want to stay aloft or gain altitude. Flight Simulator has a feature to make thermals visible to aid in learning to fly the glider.
To turn the variometer audio on/off
When soaring in rising air, if you're trying to go for distance, fly at maximum L/D, which is approximately 57 knots (105 km/h) indicated airspeed (IAS). If you're trying to stay in the lift and just increase altitude, fly at minimum sink, which is approximately 46 knots (85 km/h).
If you lose lift, you'll want to increase your speed by lowering the nose and finding rising air again. The amount of increase in airspeed should be about half of your headwind component. If you have a 10-knot headwind, for example, increase your speed by 6 mph.
One of the most challenging sources of lift for the sailplane pilot is a "thermal"—a rising current of warm air that is created in an area where the sun's rays generate more heat than in surrounding areas. For example, desert areas or brown fields generate more heat than forests and green fields. These heated areas release heat into the atmosphere and create columns of rising air.
Cruise altitude is normally be determined by winds, weather, and other factors. Long distance flight in a glider is dependent on the ability to gain altitude in thermals and then maintain the best speed for gliding distances. Without an engine, rising air is the only thing that will keep you from heading earthward.
When you can't find rising air, you have to manage the glide speed of the aircraft. The numbers to remember for the DG–808S are 45 to 1. For every one mile (1,609 meters) of altitude, the sailplane can travel 45 miles (72.42 kilometers).
That's if you have ideal conditions.
You must include a safety margin for unfavorable winds and other factors; real-world soaring pilots use a safety margin of one-half or two-thirds of the aircraft's actual performance capability.
You only get one opportunity at landing in a sailplane (except in Flight Simulator, where you can use the Slew feature to gain altitude). Therefore, you must plan your descent so that you arrive over the airport at pattern altitude. It will take some experimentation to learn how far from the airport you can fly and still make a safe landing.
Here's a test: use the Slew feature to gain one mile in altitude, and then slew 20 miles away from the airport (use the Global Positioning System—GPS—to be precise). See how well you do at getting back to the airport without having to slew again. You want to arrive in the airport pattern at around 1,000 feet (304.8 meters) above the airport elevation.
If you arrive in the airport vicinity with excess altitude, you can use the airbrakes to increase your rate of descent (press the SLASH [ / ] key, or drag the airbrake handle). Fly a normal pattern at around 52 knots (96 km/h). Abeam the landing point, extend the landing gear and set the flaps to +13 degrees (press G to extend the landing gear and F7 to extend flaps incrementally). You should dump the water ballast before landing.
Remember that if you carry excess speed on final approach, the sailplane will keep flying longer than you want it to. If necessary, deploy the airbrakes on final to allow you to slow the aircraft and increase your rate of descent.
As you cross the runway threshold, raise the nose slightly for landing. If you haven't already deployed the airbrakes, do so just before touchdown. This will spoil any lift that threatens to keep the sailplane off the ground. Hold a level attitude close to the ground, and let the sailplane settle to a smooth, level touchdown. Do not flare or the tailwheel will strike the ground, resulting in a rough landing.
Once on the ground, use the rudder for directional control as you roll out (twist the joystick, press the right or left rudder pedal, or press 0 [left] or ENTER [right] on the numeric keypad).