Aerobeez 89″ Sbach 300 Step By Step Build Guide

Posted by aerobeez On December - 3 - 2014

89″ Aerobeez Sbach300 Build Log

Sbach 300 50cc


Good day pilots, and welcome to our 89″ Sbach 300 Step By Step Build Guide! Like any other build log, we would like to start off by preparing a clean and open build area.  If you are building on a kitchen table (as many of us do), go to your local hardware store and pick up a plastic tarp to lay over the table.  This will keep dust, glue and debris from damaging your table.  There is a misconception on the difficulty in a large scale build and set up.  You will see here, it is straight forward and not difficult!  If you have any questions, please post on our Facebook page!  Now let’s get started!

 Step 1

Have your fuselage ready for some glue wicking. This is a precautionary step for all ARF’s that Pete builds.  Using thin viscosity CA and some areas, you may choose to use medium viscosity CA.  Apply the adhesive in all the areas of higher stress like the inside, outside of the motor box, and the rudder servo tray area.  The thin CA will absorb into the wood giving the wood a stronger sub frame.  It is best to “wick” the CA until you can see a slight shine overtone on the wood.  Too little CA will not be as effective.  Let the areas you just wicked set aside and dry.





Step 2

Locate your main carbon landing gear and parts.  Install the wheel axles to the carbon fiber landing gear.

Pete’s Tip:  You will want the hexagon shape of the wheel axle to have 2 vertical sides as shown here.  This will give the fiber glass wheel pants a perfect angle for installation without having to adjust the wheel axle position.



Step 3

Using blue thread lock on the wheel collars, install 2 collars and 1 wheel per axle.

Pete’s Tip: Have the set screw location facing the bottom side of the landing gear.  You do not need to tighten the wheel collars too much at this time.  The wheel location will need to be adjusted to spin freely in the wheel pants.



Step 4

Please note the angle on the carbon fiber landing gear before you install the wheel pants or install to the fuselage.  The leading edge of the carbon gear will be vertical and the trailing edge will have a slight angle.


Step 5

Using blue thread lock on the wheel pant screws and install the fiberglass wheel pants to the carbon landing gear.  Note:  The “blind” nuts are preinstalled in the fiberglass wheel pants.

IMG_0013 (2)



IMG_0015 (2)

Step 6

Adjust the wheel collars to center your wheel in each wheel pant and tighten the collars.


Step 7

Install the completed main landing gear to the fuselage with the provided screws, washers and nylon locking nuts.


IMG_0018 (3)

Step 8

Sbach 300 on main landing gear.

IMG_0018 (4)

Step 9

Before we install the tail gear assembly, we will install the rudder to the vertical stabilizer.  Use a drop of household oil in each of the pivot hinges before applying glue.  Please use Epoxy for the hinges.  Once you insert the hinges to the rudder, always check the pivot direction to insure a hinge or hinges are not off axis to the deflection angle for the rudder.



Step 10

Cut the covering away from the slots for the rudder pull/pull surface horns on both sides of the rudder.


Step 11

The rudder horns may need to be cut shorter.  This however is a personal preference. If you choose to not cut the horns, there will be more space for the rudder to deflect before the horn comes in contact with the fuselage.  This will be determined by your flying style.  Scuff the fiberglass horns on both sides before gluing in.  Epoxy is preferred.


Step 12

Rudder pull/pull horns installed.


Step 13

Test fit the rudder to the vertical stabilizer.  Once you are satisfied with the rudder gap and fitment, glue the rudder hinges to the vertical stabilizer.


Step 14

Assemble the tail wheel assembly. (The tail wheel assembly may be in a few separate parts bags)  Note the small blue piece you see in the tail assembly, Pete used a small section of the common fuel line to reduce the tail wheel from too much vertical movement.  This is not needed and is a personal preference.




Step 15

Use the carbon tail gear as a template and with a pen, mark the 3 mounting hole locations.

Pete’s Tip:  Use a 1/16 drill bit and drill 1 pilot hole.  With the self tapping screws, install one screw to hold the tail wheel assembly to the fuselage.  When you have completed that step, drill the remaining 2 pilot holes and install the remaining screws.  This will yield in the best screw alignment and keep the wood structure strong.



Step 16

Install the tail wheel to rudder guide and rod.


Step 17

Team pilot Santiago Perez showed us a great tip when cutting the covering for the servo bays.  You can see, Pete will press down on the center of the servo bay.  The reveals the 4 corners.  Mark each corner with a marker.  Using a hobby knife, slit the bay in a X pattern.  This technique prevents the use of a covering iron and keep the covering from pealing.  The covering will not need to be removed.  When the servo is placed in the bay, the covering folds to the inside.



Step 18

Using a rotor tool or sandpaper, scuff the control surface horns for the elevator.  You can also scuff the horns for the ailerons or you may have already performed these steps when during the rudder install.


Step 19

Glue the control surface horns to the pre-hinged elevators.



Step 20

Install your rudder servo into the bay.  Pilot holes are optional and personal preference.


Step 21

Use a piece of masking tape to hold the rudder in position to the vertical stabilizer.  This will make the rudder pull/pull cables easier to install and adjust.


Step 22

Have your radio gear ready. Center your pull/pull arm of choice.


Step 23

Install the 4 ball ends to the pull/pull cable rod ends.  The elevator pushrod works great as a tool to tighten the ball ends to the rod ends.  Be careful not to over tighten the ball ends.  You will need space to adjust the pull/pull cable tension.



Step 24

There are several techniques in installing a pull/pull rudder system.  Pete uses a ling carbon rod with one end of the cable taped to the tip.  The carbon rod or wood rod can bend inside the fuselage as the cable is run to rear of the fuselage exit slot. Once the cable exits the rear slot, pull the rod while holding the cable on the outside of the fuselage.  Remove the rod tape.


Step 25

Run the cable through the completed pull/pull rod end.  2 crimps are used per end.


Step 26

Loop and press down the crimps with pliers or vise grips. A drop or 2 or thin ca on the crimps works as a bit of reassurance in you choose.  Install the rod end to the rudder. Continue the same steps to the servo arm and repeat on the remaining pull/pull side.


Step 27

Pull/Pull cable installed.  Adjust the tension to your personal preference.

Note:  Pete mounts the cable ball end one on the top and one to the bottom side of the servo arm.  This will keep the cable from contact with each other.  This again is personal preference.




Step 28

Center and install the elevator servos.


Step 29

Insert the carbon fiber horizontal stabilizer spar.


Step 30

Install the ball ends to the elevator pushrods.

Note:  One side of the pushrod end is REVERSE threads.  This is to provide easy rod length adjustments once installed.


Step 31

Install the horizontal stabilizers to the fuselage and install the elevator pushrod.  You can choose to adjust the geometry and trim settings at this time or at a later time before flight.


Step 32

Sbach 300 tail section complete.


Step 33

From the website and or manual for the engine of your choice, you should be able to download a true to scale mounting template for the firewall.


Step 34

Tape the template to your firewall for standoff drilling.


Step 35

Pete will always drill 2 small pilot holes before the actual larger diameter bolt hole.  He also will only start with 1 larger top hole.  Before you drill the remaining stand-off holes, test mount the engine with one bolt.  Test fit your cowling to the fuselage.  When you are happy with the motor position, remove the cowl, mark the area for your fuel line, and throttle pushrod according to your engine.  Remove the engine and drill the remaining holes.



Step 36

The throttle servo bay is called a included “loose” bay.  The different engines on the market all have a different carburetor throttle arm position.  Locate the best area for your pushrod and servo and glue the throttle bay into position using epoxy.


Step 37

Engine installed.  The motor box is ample large enough for the mounting of your engine ignition system.

Pete’s Tip: Use a isolating piece of foam between the ignition and the motor box.  This will keep the electronic ignition from excessive vibration.


Step 38

Install your pre-plumbed fuel tank and run your fuel lines.


Step 39

If you have not installed the aileron control surface horns, install at this time.


Step 40

Using the same technique as the elevator bays, X slot the aileron bay.

Pete’s Tip:  Wick some thin CA into the aileron servo mounting areas.  Allow to dry and use 1/16 pilot holes for your servos before installing the self tapping screws included with your servos of choice.  This will increase in the servo structure area.  However, these steps are a personal preference and not required.


Step 41

Install the ball ends to the aileron pushrods.

Note:  One side of the aileron pushrod is REVERSE threads.  This is for the purpose of easy on the plane fine adjustments by turning the pushrod while attached to the control surface and servo arm.


Step 42

Install and adjust your aileron for geometry and trim.


Step 43

Main wings ready for fuselage.



Step 44

Test fit the cowling and mark the area for the engine exhaust.  Cut the cowling as needed and install the cowling.


Step 45

Set your control surface throws to your flying preference.  Range test your radio system and test CG. For CG on this ARF measure the CG from the leading edge of wing root rib.  Adjust the battery pack location. For CG proper position should be at 27% MAC. This recommendation balance point is for your first flights. The CG can be moved around later to fit your personal taste. If you are not comfortable with the calculus involved you can use this online CG Calculator. Just plug in the simple measurements and the app does the calculus.

Note: Use Diagram below as a reference for manual calculation. 


Congratulations!  The Aerobeez Sbach 300 89″ is ready for programming and maiden flight!




Always be sure to run a pre-flight check and check your onboard batteries for sufficient voltage!  Be careful and Happy Flying!

Team Aerobeez

Leave a Reply

Web Site:
Phone: 877-813-5337

Follow Me on Pinterest