 |
|
|
The Soarus motor glider from Kyosho is a durable, handsome, right-flying model. It is identical to the popular Kyosho Stratus Sport sailplane with the exception of the wing. The Soarus wing, with low dihedral, ailerons, and swept wingtips, offers increased speed and maneuverability over the Stratus. Beginners might easily start with the Stratus, and then purchase the Soarus wing kit when ready for an aileron-equipped model. More advanced pilots might start with the Soarus, then later buy the Stratus wing for a family member beginning to fly R/C. The included ferrite Mabuchi 550 motor is basic, but performs well. With the supplied folding prop and a seven-cell battery, these gliders will perform at the top of their price class. The polyethylene plastic fuselage is stronger than it looks and takes poor landings quite well. Scratches are easily hidden with a little cleaning. The plastic-skinned-foam flying surfaces are quite durable and can be repaired with tape and epoxy glue. The Soarus requires a four-channel radio. If this is a first model, the Hitec Flash 5X-G radio system is recommended. The Flash 5 features computer programming with useful mixing options, for about thirty-five dollars more than entry-level analog systems. The “G” version includes 3 micro servos and smaller receiver, ideal for the Soarus. Also required are a 30-35 amp electronic speed control (ESC) which includes Rx battery eliminator circuitry (BEC), six or seven-cell 2000 Mah battery, and charger. Not included in the kit but required for best durability are white glue, 60-minute epoxy, three small Robart "Hinge Points", 6 ounce fiberglass cloth, and one 3/16" ID flat washer. Builders should plan on spending fifteen to twenty-five hours building the model. Nothing is very difficult, but there is a lot of screwing, gluing, and cutting to be done. The wing sections should be checked to ensure that they are straight before construction begins. Some modelers have reported warped wings on the Soarus as a result of improper packing. The parts in the package should be checked against the component list. The builder should read through and become familiar with the manual, particularly the sections on servo mounting. The Soarus requires micro servos on rudder and elevator in order to clear the aileron linkage, which hangs down from the underside of the wing. Before construction is started, there are a couple areas that should be reinforced with epoxy and fiberglass cloth. For example, the horizontal stabilizer starts drooping after a few less-than-perfect landings because it is very thin and affords little purchase for the screws that hold it to the fuselage. A strip of cloth 1 inch wide, widely available as fiberglass tape, should be epoxied from the back of the horizontal stabilizer around the front and under to the back again. The stabilizer surface must be prepared by lightly sanding with 220 grit sandpaper and wiping it very clean before the fiberglass cloth is applied. It is a good idea to apply masking tape on either side of the fiberglass to reduce spillover glue but it must removed before the glue gets too sticky. A very thin coat of epoxy is applied, just enough to stick the cloth down. An old credit card works well as a scraper. As the epoxy starts to dry, a wrinkle may appear at the front of the stabilizer. Cut through the wrinkle with a sharp hobby knife while the epoxy is still tacky and then fold the flaps one over the other. After the epoxy has hardened, sand with 220-grit paper, clean with alcohol, mask, and paint with white primer. The wing joiner should be inserted into each wing half and sanded as necessary to ensure a proper fit. Fast cure epoxy should not be used to join the wing halves. Sixty-minute epoxy is stronger and allows time to align the wings to each other. Use packing tape across the joint to hold the wings tightly together until the epoxy has fully cured. The tail feathers attach to the fuselage with two long bolts coming down from the vertical stabilizer. The plastic cap nuts that are supplied work well, but on some fuselages the rear attachment point is very thin. Check your fuselage for weakness around the tailskid. For those that are weak, one hard landing can result in the skid striking the ground first, which will crack the fuselage around the rear nut. To reduce the chance of this happening, the area on both sides of the nut can be covered with a single piece of 1" fiberglass tape wrapped around the back. This area should be roughened with 80-grit sandpaper. The cloth is stretched over the area and covered with epoxy. When the epoxy is starting to set, build up some extra epoxy around the nut contact point. Press a flat washer of the correct inner diameter into the epoxy until it contacts the fuselage. This will build up a boss to spread the compression forces. Any excess epoxy that remains inside the hole of the washer can be removed with a hobby knife after the epoxy has hardened. The tape supplied by Kyosho for rudder hinging is inadequate. Robart small "Hinge Points" are recommended as a replacement. Installation should begin with hand drilling 1/16" pilot holes, then carefully opening the holes to the appropriate size. The hinges should be disassembled before gluing. Next, the inside of each hole with glue and the female hinge points are pushed into holes in the vertical stabilizer with the flats all facing up. Before the glue sets, a piece of music wire is passed through all the hinge points to ensure proper alignment. This process is repeated with the male points in the rudder. Finally, the hinges are assembled by pushing the male points into the female and adjusting the fin/rudder gap to a hairline. This makes for a strong, removable rudder. This must be done after the horizontal stabilizer has been mounted to the fuselage. Do not use standard CA glue for any foam/plastic on the model. It will melt the parts quickly. Plastic tape should be wrapped around the rudder pushrod where it crosses the elevator pushrod in the fuselage. This will eliminate the metal-on-metal contact and reduces radio interference. The supplied plastic tube is used to route the receiver antenna to the rear and the excess wire hangs out the back of the model. Glue squares of 1/4" plywood under the attachment points for the battery tray, drill pilot holes, and coat with CA glue. The motor battery should be as close to the servos as possible. The model will almost certainly be nose heavy as compared to the recommended CG, so the battery tray rear flange should be cut to fit around the servos. This moves the battery back about 1/4". Control response with Kyosho's suggested control throws is very good. Electrical tape is used to hold down the canopy as the manual suggests. If the canopy is screwed on, it will crack in a hard landing. The Soarus is an excellent flyer. Control response is crisp and precise. As mentioned above, it is fast and it penetrates well. The Soarus can be flown more like a power plane than glider - climb to 250 feet, dive down for a 90 MPH low pass, pull up, snap roll, wing over at 200 feet, and back for another pass. It can be flown leisurely with a little lift, but it flies best with some speed. A six-cell battery is adequate in light wind with moderate lift. When it gets windy though, or if the lift goes away, the seven-cell pack really shines. On a calm day with little thermal activity 4 to 10 minutes of flight can be expected with either battery, depending on throttle settings. The manual points out that the motor has no downward deflection in the mount meaning that airplane will climb when power is applied. In fact, if the plane is trimmed for a nice slow glide and power is applied, it will try to climb at 40 degrees. When it reaches the point that it does not have enough speed to maintain the climb, it will stall. This must be kept in mind and the pilot should be prepared to give down elevator as needed to maintain airspeed under full throttle. The slippery shape that makes this airplane so fast and fun also makes it challenging to land in the beginning. The forward CG and efficient wing combine to make very flat landing approaches. Overshooting the landing area on light-wind days can be hard to avoid. This sounds like a liability, and it sometimes is, but it can be a lot of fun managing a long, flying landing. A moderate headwind to slow descent helps. The Soarus offers excellent performance for the price. It looks great and flies the way it looks. |
|