RCU Review: Great Planes Slinger - Kontronik Brushless 400 Set

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    Contributed by: Greg Covey | Published: November 2004 | Views: 142998 | email icon Email this Article | PDFpdf icon
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    A Great Planes Slinger is an inexpensive 47.4" ARF wing that comes with a Speed 400 motor and two props for astonishing stunts at a wide range of speeds. The only things required to make the Slinger ARF flight-ready are 6-minute epoxy and about an hour of easy assembly. All-foam parts make it a snap to assemble and tough to damage.
    Stock Number: GPMA1180
    Wingspan: 47.4 in (1205mm)
    Wing Area: 459 sq in (29.6dm2)
    Weight: 23 oz (650g)
    Wing Loading: 7.2 oz/sq ft
    Includes: Speed 400 motor & prop
    Requires: 3-channel radio with 2 mini or micro servos; 15 amp electronic speed control; electronic mixer; 8-cell, 1100 mAh battery & charger
    Formed plastic parts, factory-applied heat-shrink film and all necessary hardware are supplied along with a Speed 400 motor and two props

    The wing comes almost complete with several custom plastic parts like an integrated battery bay, canopy, and metal connecting bars. The model assembles in about an hour and flies very well using the stock power system.

    What makes it a "Super" Slinger?

    A Super Slinger uses the new Kontronik Brushless 400 Set instead of the stock Speed 400 motor.

    Although similar in size, the Kontronik Brushless 400 motor provides significantly more power!

    The direct drive 400-size brushless motor comes with a 30-amp Kontronik Smile ESC. Although the two motor sizes are similar, the Kontronik FUN400-23 motor provides significantly more power!

    The Kontronik Brushless Sets combine matched components to eliminate the guesswork

    The Kontronik Brushless Set 400 includes a Fun 400-23 brushless motor and a matched Smile 30-6-12 ESC. The power set is meant for direct drive applications up to 12 cells NiCd or 3 cells Lithium. Both the motor and controller can handle currents up to 30amps which make it significantly more powerful than the stock Speed 400 motor. It is also a perfect plug-n-play replacement fit for fast and easy assembly!

    The new 15C Kokam 2AH packs can provide almost 3 times the current of the 1500mAh pack

    To power my "Super" Slinger wing, I'm using the new Kokam (15C) 2AH 3-cell Lithium pack. Not only is the 30amp continuous current delivery a perfect match for my Kontronik Brushless 400 set but the 6oz. pack size fits perfectly into the stock Slinger battery bay.

    Connectors are provided for both motor and controller

    Before installing the motor, you need to solder the connectors onto the motor and ESC wires. The Kontronik Brushless 400 Set includes plugs, connectors, and pre-cut shrink tubing. I soldered the male plugs onto the motor wires.

    The antenna position shown above did not work well due to ESC interference

    I'm using an M-72-6 antenna from E Cubed R/C that I tucked under the center plastic tray. It will keep from having a long antenna flopping around during high-speed maneuvers. Note that during the flight testing, I had significant radio interference, due to the orientation of the antenna to the ESC, so my placement of the M-72-6 antenna was not optimal.

    Normally, the servo is held in place by tape and some balsa wedges, if needed. I decided it best to epoxy my HS-81 servo in place to provide a more solid hold for the higher-powered Super Slinger.

    Although a weaker servo can be used when running the stock Speed 400 motor, it is best to choose a stronger servo like the Futaba S3101 or Hitec HS-81 when using a brushless power system.

    Two metal bars slide into tubes to connect the wing halves

    The wings are attached by two metal bars that slide into pre-installed tubes. Again, for added strength, I glued the wing halves together using thick, white craft glue. At this time, you can add the new plywood skid, if desired, for easier launching. Note that the wing centers and tips have plywood plates for easy gluing.

    Strapping tape and white shipping tape are used to strengthen the assembly

    I used three different tapes to strengthen my Super Slinger. The clear cellophane tape is included in the kit but makes for a rather weak joint on large areas. I used the nylon-reinforced strapping tape as a first layer to hold my battery tray onto the wing. I then covered it in some areas with the white shipping tape for a better finished look. Be certain to tape every surface of the plastic tray where it meets the wing using long pieces of strapping tape from top to bottom.

    The elevons are reinforced with clear cellophane tape on both sides at each end

    The 3-cell Kokam (15C) 2AH Lithium pack fit perfectly in the battery tray

    The Kontronik 400 brushless motor mounted perfectly in the stock position although I used a heavier tywrap than provided in the kit for the Speed 400 motor. I used a Graupner 5.5x4.5 CAM Speed prop and Graupner 6053.31 prop adapter for 3.2mm shafts. Both parts were obtained at Hobby Lobby. Note that the prop front faces forward and will spin clockwise when viewed from behind the wing. If the motor spins the wrong way, reverse any two of the three motor wires going to the ESC.

    Great Planes supplied a Product Improvement Sheet and additional parts in the kit

    Great Planes supplied a Product Improvement Sheet with the Slinger as an addendum to the manual. Also included were some new parts for providing alternate methods to launch the plane and attach the wingtips.

    The new wingtip mounting allows for them to be screwed in place and eliminates the need to remove the inside section of the decal. This makes the wingtips removable for travel or storage. I still choose to glue my wingtips in place since the wing ends now have a nice light plywood mounting plate instead of foam. I removed the section of decal after tracing the wing end onto the tip and then roughed up the exposed area of plastic with sandpaper.

    A thick plywood center keel is now supplied that makes launching the Slinger much easier. The plastic center section has also been re-designed to minimize any additional weight needed for balancing. Since I am an "old school" wing enthusiast, I optioned to leave the keel off and launch it in the traditional manner.

    The plastic wingtip was epoxied to the plywood end plate after removing a section of the decal

    The bottom view reveals the slight cutout in the foam needed for prop clearance

    My Slinger balanced perfectly at the recommended 8" distance from the tip using the Great Planes CG Machine

    My Super Slinger was Ready-To-Fly at 27.1oz using the 6oz. Kokam 3-cell (15C) 2AH Lithium pack.

    My Super Slinger was Ready-To-Fly at 27.1oz using the 6oz. Kokam 3-cell (15C) 2AH Lithium pack. The power system drew 21amps using the Graupner 5.5x4.5 CAM Speed prop.

    The static power test revealed incredible pushing power! The rather loud characteristic wing noise was also present due to the close proximity of the prop to the body. I was anxious to test fly it on the upcoming weekend.

    Test Flying:

    My first opportunity to test fly the Slinger was in very windy conditions. The wind was gusting from 15-20mph and this is something that I would never recommend to anyone regardless of their experience. We call this scenario, "do as I say, not as I do!" It was interesting to see the plane perform in these conditions because it clearly demonstrated the upgrade in power level from the stock Speed 400 motor to the Kontronik Brushless 400 Set. Although the flights were a bit intense, they were very successful and I walked away without any damage.

    The "Super" Slinger had plenty of power, even at half-throttle! My CG seemed a bit too aft as the elevator was over-sensitive. After the flight, I realized that I had experienced many glitches in the control surfaces and throttle setting so I replaced the M-72-6 Micro antenna with a normal wire antenna that I taped along the bottom of the wing. Since I had sealed the micro antenna under the plastic tray, I cut the wire near the receiver and soldered the original antenna wire back in place. The wire is held in place using white shipping tape. The next flight worked perfectly without a glitch! Additionally, I filled the nose under the plastic tray with some modeling clay since the Lithium battery pack was as far forward as possible. The additional clay weighed about half an ounce.

    The new antenna wire was routed around to the wing bottom and taped in place

    Our next flights during the week were in much calmer conditions. The dynamic range of flight on the "Super" Slinger now encompasses thermaling to perhaps 80-90mph! I saw no structural problems and flew most of the flight at 1/4 to 1/2 throttle. When the flight was over, the Slinger gracefully glided without any power to a slow, soft landing in the grass. Notice the Met Life blimp in the background for the LPGA tournament that week in Rochester, NY.

    The introduction of the new Kontronik Brushless 400 Set to the Great Planes Slinger wing increased the dynamic range of flight on an already great design to nothing short of spectacular! Without detracting from the slow gliding and thermalling characteristics on the original lightweight design, the substantial increase in power level allows a new top end performance that can be used in almost any weather conditions.

    A perfect power supply for the Kontronik 400 motor is the new 6oz, 3-cell Kokam (15C) 2AH pack. It can provide a continuous 30 amp current delivery to match the needs of the Kontronik Brushless 400 Set. Even at full-throttle on my "Super" Slinger setup, the Kontronik Brushless 400 motor, Smile 30-amp ESC, and Kokam (15C) 2AH Lithium pack are only using 2/3 capacity so nothing is getting stressed in the power system when delivering spectacular performance! The built-in air scoop of the Slinger keeps everything operating at a cool temperature.

    This wing flies awesome! The flights are about 15 minutes with mixed hard and easy flying. Unlike the Speed 400 motors, the Kontronik Brushless 400 power system will never wear out.

    If you have already mastered your Speed 400 wing and are looking for a performance upgrade, the new Kontronik Brushless 400 Set can turn your Great Planes Slinger into a real "Super" Slinger!

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