AT A GLANCE Type:
Construction: Wing span: Wing area: Airfoil: Length: Weight:
Wing loading:
R/C electric aerobat balsa
50 inches 500 sq. in. symmetrical 44.25 inches 3.5 pounds
16.3 oz./sq.ft.
Motor: 32-class brushless 700–900Kv ESC:
Battery: Radio:
Servos: Manufacturer: 50–60-amp 4S 2500–4000 mAh Li-Po
4-channel transmitter with Futaba R617FS
(4) Hitec HS-82MG
SIG Mfg. Co., Inc. 401-7 South Front Street Montezuma, IA 50171-0520 641-623-5154
www.sigmfg.com
have been experiencing in the Northeast this winter. Before starting assembly, I used my heat gun to tighten up the covering on all of the Sbach, with my iron being necessary in a few stubborn areas. Care must be taken with heat application because of the many different trim pieces on the airframe. Yes, every black checker is an individual piece. After a few minutes of gingerly applying heat, my Sbach was looking perfect, and as- sembly could commence.
The Sbach first starts to come together with the assembly of both wing halves and instal- lation of the aileron servos. The Sbach uses a total of four micro servos, and torquey metal gears are highly recommended. Each aileron gets its own servo, which in my case were Hitec’s HS-82MGs. The servo openings are pre-cut, so it should be a simple matter of dropping them in and screwing them in place. However, mine required just a tad of trim- ming to make the slot just a bit longer. Next, I hinged the large ailerons using thin CA. T-pins can be used to help center the
SIG’s Sbach comes out of the box with a very low parts count. The paint work on the cowl and wheel pants is first class, and the trim scheme is striking.
hinges, but I prefer to center them by hand to reduce the chance of weakening them. Aileron control horns come next. Each horn is held in place with three wood screws. Since these horns do not use backing plates and just bite into the aileron wood, harden- ing the screw holes with thin CA is a good idea. The pushrods are then assembled and installed, which requires bending and cut- ting the pushrod wire ends to align with your servo arm. I quickly found that the plastic arms included with my HS-82MGs were go- ing to be too short to achieve 3D-level throw while retaining proper geometry. Instead I installed Hitec’s longer adjustable arms. The Sbach has two-piece main gear and you need to join axles to each individual leg. An inside and outside collar contain the wheel. Unlike some ARFs whose parts re- quire cutting, SIG has provided axles the proper length and ready to hide inside the wheel pants. The pants are held to the gear legs with two machine screws each. Each gear leg can then be slid into the bottom of the fuselage and are held in place with more screws. Everything lined up perfectly
and there was no need for any trimming or finagling here.
The tail feathers are addressed next. The elevator halves and the joiner wire are al- ready glued together for you. The elevator as- sembly just needs to be glued to the stab via CA hinges. After screwing on the elevator control horn, temporarily install each wing half on the the aluminum wing spar for align- ment. Now fit the horizontal stab. Mine lined up perfectly with no sanding necessary. The covering on the center of the stab is pre-re- moved for you, so all you need to do is mix up a batch of epoxy, make sure the stab is square to the wing and fuselage and glue it in place. Next, you will glue the vertical stabilizer to the fuselage. Again, all of the covering in the gluing area is removed for you and no sanding was required. A control horn screws to the large rudder, which can then be hinged to the rear of the fuselage, again with CA hinges. Lastly, the tailwheel as- sembly and bearing get screwed and glued in place on the underside of the fuselage. My tailwheel required very slight bending for proper alignment.
One assembled gear leg for the Sbach (above left). No trimming of axles required here, everything just simply bolts together painlessly for a quick
FLYING MODELS
assembly. Each gear leg slides cleanly into the bottom of the fuselage (above right) for a clean, finished look.
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