ICARE: DG-800S

Model Airplane News, Jul 2004 by Iasilli, Sal

Cutting-edge scale glider

The full-size DG-800S sailplane is manufactured in Germany by Glaser-Dirks (now DG Flugzeugbau), and its wing design is state of the art for a racing glider. It can be flown in either the 15-meter or the 18-meter class by adding wing-panel extensions, or "winglets." Its highly successful competition record, especially in Europe, speaks for itself.

The DG-800S model is a composite replica of the full-scale racing sailplane. It comes with two wing lengths just like its full-size counterpart: a 138-inch wing with large fiberglass, plug-in winglets represents the 15-meter class, and a 165-inch wing with plug-in extension wing panels and mini fiberglass winglets represents the 18-meter class. This new breed of model sailplane is classified as "super scale," which means that it incorporates many scale features not ordinarily found in almost-ready-to fly (ARF) models, such as a fabric-padded cockpit tray, a molded-fiberglass mushroom instrument console, side levers, a communication microphone, a front-hinged canopy with locking mechanism, sliding side-vent window, a fitted and painted canopy frame, a tailwheel, retractable landing gear and fully applied graphics.

* Basic construction. The fiberglass fuselage is finished in gleaming white gelcoat and has the elevator and rudder control tubes with inner wires already epoxied into place. The wings are made of white foam with full-length carbon-fiber-reinforced spruce spars; they are sheeted with fiberglass cloth, sandwiched with balsa and covered with white film. Steel wing blades come installed in each wing panel, so the wings are easily mounted on the fuselage. Nylon bolts are used to mount the stab on the fin. The ailerons and flaps are also hinged in the covering process. The rudder, elevator and stab are also made of foam and covered with balsa and film. The double-deck spoilers are factory installed. Cutouts for the ailerons, flaps and spoiler servos are provided.

* Radio installation. The scale cockpit tray that holds a full-length pilot figure takes up most of the forward cockpit area. This makes it necessary to mount the rudder, elevator and retract servos at the rear of the tray. The receiver is mounted just below and forward of the servos, and a 1500mAh battery pack sits just in front of the receiver. I soldered threaded brass couplers to the provided music wire going to the servos and control surfaces along with Du-Bro Kwik-Links. Hitec's HS-81MG metal gear servos mounted on the outer wing panels activate the ailerons and also the spoilers, and HS-225MGS were used for the flaps. The rudder and elevator servos are Airtronics 141s. The retract servo is Airtronics' standard, heavy-duty servo that also activates the aero-tow release mechanism.

* Scale finishing touches. The DG canopy/cockpit is so large that it requires a full-body pilot figure. 1 used the ¼-scale glider pilot from Icare; it is very light and looks realistic. The scale instruments are from Hobby Lobby. all the DG graphics are factory applied, with the exception of those for the lower wing; apply those after you have installed the servos.

PREFLIGHT SETUP

It took approximately 4 ounces of lead in the nose to balance the model at the recommended CG. A red arrow on each fuselage side indicates the proper location. I programmed my radio for 25 degrees up and 12 degrees down ailerons, 35 degrees right and left rudder, 15 degrees up- and down-elevator, 45 degrees down flaps with 10 degrees elevator compensation mixed in, 3 to 4 degrees down wing camber (flaps and ailerons) for thermalling, and 1 to 2 degrees up wing reflex (flaps and ailerons) for high-speed flight. For winch launching, I mounted one towhook on each side of the fuselage, 1 inch below each wing and 3/8 inch forward of the CG. This arrangement requires a bridle harness with steel rings that attach to each towhook. The bridle is then attached to the winch line with a swivel fishing clip. This is the safest way to winch-launch large-scale sailplanes without the worry of stalling on takeoff.

For aero-tow launching, I installed a simple tow release using the leftover control-wire tubing from the rudder. I soldered one end of the inner control wire with an adjustable clevis quick link and attached it to the retract servo arm. 1 fitted the control-wire tubing under the cockpit tray and the battery pack. I then epoxy-glassed the end of the tubing to the forward cockpit floor just in front of the canopy tray. I cut a 116-inch slot through the tubing and a 3/8-inch slot through the fiber-glass fuselage floor. The tow-line loop is then simply inserted through the floor cutout, and when the retract servo is in the down position, this activates the control wire and captures the tow loop in the wire tubing setup. When the landing gear is in the up position, the retract servo will pull the wire back and release the tow loop that is attached to the tow line. This is a simple and very reliable tow-release setup.

CONCLUSION

The DG-800S is everything you would want in a large-scale sailplane-beauty, high performance, versatility, affordability and, best of all, it's fun to fly. I highly recommend it to anyone who is looking to venture into the purity of silent flight.