RCU Review: Sig XA41 Sbach 300

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    Contributed by: Jim Buzzeo | Published: April 2014 | Views: 17909 | email icon Email this Article | PDFpdf icon
    RCUniverse.com Review of the Sig XA41 Sbach 300 ARF
    Jim Buzzeo
    (AMA 74894)

    Email Me

    SIG Mfg. Co., Inc.

    P.O. Box 520
    401-7 South Front Street
    Montezuma, IA 50171-0520
    Phone: (641) 623-0215

    If you've been involved with RC Airplanes for any amount of time, you've probably heard of Sig.

    Started in 1951 by Glenn and Hazel Sigafoose, Sig has been a leader in the RC industry for over 60 years, supplying high quality aircraft wood, kits, building supplies and of course Almost Ready to Fly (ARF) Airplanes.

    Still located in Montezuma Iowa, Sig produces over 2,000 products from their 80,000 Square foot facility.

    Recently I was asked to review one of Sig's latest releases: the electric powered XA41 Sbach 300. Since I have been building Sig kits for as far back as I can remember I jumped at the opportunity to try out this great looking ARF. Let's dig in!

    • Handcrafted All Wood Construction
    • CAD Drawn, Laser Cut, Factory Jig Assembled
    • 2 Piece Wing
    • Aluminum Wing Tube
    • Formed Aluminum Landing Gear
    • Covered in Genuine Ultracote
    • Fiberglass Cowl and Wheel Pants
    • Complete Pushrod & Hardware Package
    • Photo Illustrated Instruction Manual

    • None as Tested

    Skill Level:

    Time Required to Build:

    Frustration Level:

    What do these ratings mean?

    Name:Sig XA41 Sbach 300

    Price: $189.99 (Price at Review Publishing Date)
    Wingspan: 50" (1270mm)
    Wing Area: 500 Sq.in. (32.2 Sq.dm.)
    Weight: 3.25 - 4 lbs. (1274-1812 g)
    Wing Loading: 12.6-21.9 oz./sq.ft (60-67 g/Sq.dm.)
    Length: 44.24" 1124mm)
    Radio Required: 4 Channel (Minimum) with 4 Micro Servos

    Items Needed To Complete:

    • 4 Channel Radio (minimum) and Receiver
    • "32" class Brushless Motor (700-9000 kv)
    • 60-75A Speed Control (ESC)
    • APC 13.x 6.5E Propeller
    • 4 Micro Servos
    • 4S 2500-4000 mAh LiPo Battery and LiPo Charger
    • Thread Locking Compound, CA, and Epoxy

    The Sig Sbach arrived double boxed to minimize any damage that may occur in shipping. Inside, the Sbach was packaged beautifully, with each sub assembly in its own plastic bag. A quick inventory included a nice bag of hardware, wheels, aluminum landing gear, spinner, fiberglass cowl and wheel pants and aluminum wing tube. All major assemblies were individually bagged and secured.
    There was some minor wrinkling in the genuine Ultracote covering (which is always to be expected with a precovered airframe) but everything else looked perfect.


    The manual is very well written in proper English. I was very pleased to see very little left to the imagination. I highly recommend reading it from cover to cover. The 10 minutes invested in reading the manual pays big benefits, and virtually eliminates guesswork.

    Download the manual

    Wing Assembly

    Typical for a pre-covered ARF, there were some wrinkles in the Ultracote as I mentioned. A bit of patience pays off big here! Take your time and begin with a covering iron set at low heat. I carefully heated up the Ultracote with my iron, and within a couple of minutes, the covering looked nearly perfect. Do take care not to heat the Ultracote too quickly, otherwise you may induce bubbling in between the covering layers.
    Next I installed the aileron servos in each wing. Remember to drill pilot holes, and use thin CA to harden the servo mounting holes. Hinging was completed very quickly and easily. It is VERY important to properly install the hinges. I installed the hinges on all flying surfaces at once, EXCEPT for the lowest rudder hinge, as this must not be done before gluing the vertical fin in place.

    Next, the control horns were installed, again making sure to use thin CA to harden the balsa around the holes. Sig supplies pushrods threaded on one end, with an 'L' bend and plastic keeper at the other.

    Mark the pushrod carefully and put a 90 degree bend at the mark. Cut off the extra wire and install the pushrods.

    Landing Gear Assembly

    The Sbach's supplied landing gear, wheels, wheelpants and hardware are fairly high quality. After securing the axle to the landing gear, I test fit the wheel pants. There is a slot cut into the wheel pants that fit almost exactly over the nut securing the axle. You may need to slightly trim the wheel pants to fit, although mine came out perfect right from the box. DO use thread locker on these nuts.

    Once I double checked that everything fit properly, I assembled the landing gear, paying attention to details (remember to attach the wheel pants facing forward!) and using thread locker on all metal to metal joints.
    The landing gear itself is attached with four screws and lock washers.

    Tail Installation

    Next the elevator is hinged using the same procedure as the ailerons. Now it's time to test fit the wings and horizontal stabilizer. Make sure the stab is perfectly aligned with the wing and fuselage. You may need to use masking tape, pins, balsa shims, etc to make sure the stab is as perfect as you can get it. I was not surprised that my Sbach aligned perfectly without anything extra. I used 15 minute epoxy on the stabilizer to allow time for any last minute adjustments. clean up any excess with rubbing alcohol before the epoxy cures.

    Now it was time to attach the vertical fin. Using the same procedure as the horizontal stab, I dry fitted the assembly to the fuselage and checked that is aligned properly. Again, it came out as perfect as the horizontal stab. I mixed up some more 15 minute epoxy, and glued the fin in place. If you follow along with the manual, now you would hinge the rudder in the same manner as all the other flight surfaces.

    The tailwheel was installed next. There are two pinholes pre drilled into the rear bottom fuselage. The height of the tailwheel wire is set using a wheel collar. The manual notes to 'tweak' the angle of the tailwheel steering rod if required. Two screws hold the tailwheel assemble in place, and a nylon bearing is used to attach the steering rod to the bottom of the rudder.

    Motor, ESC and Cowl Installation

    The Sbach comes with a sliding firewall assembly to allow a wide range of motors to be used. The Manual is very clear on how exactly to measure your motor to set the firewall exactly where it should be so the cowl and spinner line up nicely.

    After the measurements were complete, I tack glued the firewall in place, mounted the motor and aligned the spinner and cowling.

    Finishing the cowl and ESC installation was a snap. With the spinner in place and taped in position, and using the predrilled holes in the fiberglass cowl, I drilled four pilot holes and used four wood screws to secure the cowl. After double checking that everything looked right, I removed the cowl, and securely glued the firewall with epoxy and triangular stock.

    The ESC is held in place on the right side of the motor box with hook and loop fastener. Very tidy, efficient and hassle free.

    Receiver, Elevator and Rudder Servos, and Pushrod Installation

    Moving back inside the fuselage, the elevator and rudder servos were installed next. The pre-cut servo holes fit my Hitec HS-85 servos perfectly. Start by drilling pilot holes for servo mounting, using thin CA again to harden the balsa around the mounting holes.

    Using the same procedure as with the aileron pushrods, carefully mark the pushrod, bend a 90 degree angle, cut off the excess and add the plastic keeper. Use the threaded end of the pushrod externally at the control horn for easier adjustments at the field.

    I installed my receiver at the specified location in front of the elevator and rudder servos. Another piece of hook and loop fastener holds the receiver in place. I decided to use a 'Y' cord in lieu of using separate channels for the two aileron servos, either way is very simple to do.

    It's almost ready to fly! Time to triple check all hinges, control horns, servo directions, etc. As always, I first removed the propeller. I chose to set up the radio by attaching a 4 cell NiMH battery pack to the receiver, simply as a safety precaution. Once everything was working to my satisfaction, I removed the NiMH battery, attached a 4 cell lipo to the ESC and made sure everything was still in working order.

    Final Touches

    Attaching the canopy to the battery hatch was also very quick and easy, the fit was perfect right out of the box. The manual mentions using a flexible RC-56 type glue. I used Foam Tac by Beacon adhesives, which worked great for me. I ran a bead around both the canopy and the hatch, and glued in place. Once cured, I fitted the hatch to the airframe and was happy to see that it came out almost perfect.

    Finally, I added the prop, spinner and flight battery and checked the CG. With a 4000Mah four cell Lipo, the Sbach balanced slightly tail heavy. I added one oz of lead to the firewall, which brought the CG back into range. The combined total weight of the battery plus lead was 14.5 oz.

    One final check of the control surfaces (low and high rates) and the Sbach was complete and ready to fly!

    When flight test day arrived I was more than a little excited to see how the Sbach would perform, and Sig came through with flying colors (no pun intended). Temps were in the 40's, nice for Minnesota in March. Winds were light and variable.

    After performing a range test, I taxied the Sbach to the runway centerline, and smoothly advanced the throttle. The Sbach required a little right rudder during the (short) takeoff roll and we were flying! Climbout was spectacular. One quick trim pass and the Sbach began to impress. Roll rate was quicker than I had expected, rudder authority was VERY good, and elevator was as I prefer: not too sensitive (or 'pitchy') but very crisp. I was smiling from ear to ear.

    Next I brought the Sbach to a decent altitude for some slow speed / stall testing. Power off stalls showed no signs of dropping a wing, and leaving some power in did not cause the airplane to display any bad manners. Snaps and spins were very controllable: I could start or stop a snap almost instantaneously. Now I could bring the airplane down low and have some fun.

    Again, the Sbach delivered. Roll rate truly impressed me especially considering that I was still using 'low' rates. Big smooth loops, Cuban 8's, very nice rolls (axial and point rolls) were easy as pie.

    Flying the Sbach was pure fun. Once I had gotten comfortable with it, knife edge flight was great. A little down elevator was required for it to hold a straight line, which can be either "mixed out" with your computer radio, or you can do it "old school" and simply hold in the elevator command.

    Rolls were a thing of beauty. If I slowed the Sbach down, (keeping the nose up) the roll rate would slow down very nicely. It seemed like only three or four minutes passed before the seven minute timer I had set went off and I reluctantly brought the Sbach around for landing.

    I discovered I could either come in higher than normal with the throttle closed, or I could slow it down early and keeping in power I could "drag" it in as slowly as I wanted to. The Sbach didn't seem to care one way or the other. Control authority felt rock solid either way. Flaring slightly over the threshold and the Sbach smoothly rolled to a halt. "What a great airplane!"

    Sig XA41 Sbach 300 ARF

    All in all the Sig Sbach is hard to beat. It can be set up to be well mannered and docile, or to be a crazy 3D powerhouse that will satisfy the needs of any hard core 3D flyer, or most anything in between. Sig really did their homework on this one, which is no big surprise. My hat is off to the folks at Sig!

    SIG Mfg. Co., Inc.
    P.O. Box 520
    401-7 South Front Street
    Montezuma, IA 50171-0520
    Phone: (641) 623-0215

    Comments on RCU Review: Sig XA41 Sbach 300

    Posted by: celso.ferraz on 05/02/2014
    Excellent description. I appreciated it, congrats!
    Posted by: teckbot on 05/27/2014
    Great review and build log. My only one complaint with this plane is the checker board pattern on top of wings. Goes against all common orientation pattern schemes. Oh yeah, looks kind of funny with an empty cockpit.
    Posted by: Jvbtte on 08/24/2015
    Page: 1
    The comments, observations and conclusions made in this review are solely with respect to the particular item the editor reviewed and may not apply generally to similar products by the manufacturer. We cannot be responsible for any manufacturer defects in workmanship or other deficiencies in products like the one featured in the review.

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