The SIG SOMETHIN EXTRA was conceived as an all out fun fly design that does not necessarily look like one. Sure, it has the large, thick symmetrical wings along with generous area and large flight control surfaces, normally associated with fun fly type models but when the whole thing is put together, it s really a great looking airplane! We also wanted this model to be as much fun to build as it was to fly, so we decided early on in the project to produce all of the parts with our laser cutting system, to assure absolute accuracy throughout the building process. The result is that the SOMETHIN EXTRA builds so fast and so accurately, it is almost in a class by itself. The design is totally unique for this type of model in that the wing panels are separate and removable, using an aluminum tube joiner directly through the fuselage. This set-up has a lot of benefits, such as being able to locate the wing panels directly on the thrust line and having virtually the entire fuselage, forward of the trailing edge, available for radio installation and access. Of course, transportation and storage of the finished model also becomes easy and convenient.

The flight characteristics of the SOMETHIN EXTRA are nothing short of incredible. It is fully capable of ultra short field take-offs and landings and almost anything in between. An astounding roll rate, knife edge flight to the next county, instant spin entry and exit, tight inside and outside loops and superb low speed handling are just the beginning! This design has outstanding ground handling characteristics and can be flown in considerable wind conditions. We can t think of a better club contest airplane than the SOMETHIN EXTRA! While this design can certainly be flown with a normal 4-channel radio and five servos, it really gets fun when you use one of today's simple programmable computer radio systems. These radios allow you to mix surfaces, employ flaperons and fine tune and maximize the performance of this model to create an airplane that is nothing short of spectacular in the air. We would also advise you that this is definitely an airplane that benefits from the use of a radio system with dual rates on both the ailerons and elevators. When the model is set-up as suggested in these instructions, you will have an airplane that simply does it all! If you have been looking for a design that is fully up to your flying skills, then the SIG SOMETHIN EXTRA was designed and engineered just for you.

The SOMETHIN EXTRA kit has been very carefully engineered to provide you with an enjoyable building experience. The plans were developed using our powerful CAD (Computer Aided Design) system. To insure absolute accuracy, the individual parts themselves were then generated using these same plans through a path directly to our computerized laser cutting system. This methodology produces incredible accuracy, minimizing and/or eliminating the need to prepare parts prior to assembly. When the above system is used in concert with SIG s legendary quality balsa and plywood, the result is a kit that has only been dreamed of until now.

Your SOMETHIN EXTRA kit is very complete. We have included almost all of the hardware that is required along with a very high quality custom made landing gear and wheel pants to match. However, there are still a few items that you will need to complete this kit. Some of these are:
  • 4-Channel Radio System w/ 5 Servos
  • Spinner: 2-1/4 Dia.
  • 6 Aileron Servo Lead Extension - 2 required
  • Wheels: Two 2-3/4 Dia. Mains, One 1 Dia. Tailwheel
  • Engine: .40 - .46 2-Stroke or .56 - .65 4-Stroke
  • Glue: Thick or Medium and Thin CA and 5-Minute Epoxy
  • Paint: Engine Compartment and Wheelpants
  • Propeller
  • Covering Material: 2 - 3 Rolls (See Covering Section)
  • Fuel Tank: 8 Ounce

Engines, Propellers And Mufflers

We have flown our prototypes using two-stroke .40 size engines with excellent results. Our engines were bearing equipped, not the plain bearing type. Plain bearing (or bushed ) engines will likely fly the model adequately but will probably not have the top end power for extreme vertical maneuvers. Understand that the SOMETHIN EXTRA was not designed to be a fast airplane but rather a highly aerobatic model. It therefore flies best when equipped with a strong .40 to .46 (even .50 class) engine with bearings. Throttle management through various maneuvers is of course suggested and will result in smoother flight and a lot more fun.

Four-stroke engines will also fly this design. However, by the nature of their construction, they are always heavier for any given displacement. Since it is essential that the airplane balances at the point shown on the plans, using a four-stroke engine may require additional weight and balance considerations to achieve the correct center of balance (or CG).

When using two-stroke engines, avoid heavily pitched props. Ideally, you want your engine pulling as well vertically as it does in horizontal flight. To do this it needs to run at or about its best rpm level to take advantage of its power curve.

Always use an effective muffler! A loud engine could cost you (and possibly your club) the use of your flying site if it offends nearby non-modeling neighbors. Use the muffler that came with your engine or an after-market muffler made especially to quiet two-stroke engines.



IMPORTANT: The laser cut parts contained in this kit are extremely accurate in outline and fit. They are meant to be used directly out of their sheets, without any trimming or sanding unless specifically called for in the instructions. The laser cutting process produces a brownish edge to the parts and, in some cases, a blackout edge may result when cutting harder plywood parts. CA adhesives work perfectly on these parts and they do not need to be sanded to remove the discolored edges. In fact, sanding the edges of laser cut parts can change their shape and/or dimensions, resulting in a poor fit. DO NOT edge sand the laser cut parts in this kit.

Our prototype SOMETHIN EXTRA models were built almost exclusively with SIG Thick CA (cyanoacrylate) glue, SIGCA021 and our Kwik-Shot accelerator, SIGCA030. We use and recommend this glue for several good reasons. The thicker CA formulation provides you with a little more time to properly position the parts. Thick CA does not tend to run and also fills small gaps between parts. Using the Kwik-Shot accelerator along with the thick CA allows you to set the adhesive as required for different types of gluing operations. Some builders may wish to work with the SIG Medium CA glue, SIGCA012, along with the Kwik-Shot accelerator. This glue also works well but with somewhat less working time than the thick variety. SIG Thin CA, SIGCA002, is used to install the Easy Hinges and to adhere reinforcing fiberglass tape in specific locations. We also suggest that you have a bottle of SIG CA Debonder (SIGCA040) available during the construction of this model.

One of the fuselage construction steps will call for the use of aliphatic resin glue, such as our SIG-Bond product SIGSB001. The only epoxy glue that you will need to build this design is SIG Kwik-Set 5-minute Epoxy Glue, SIGKS001.

CAUTION: Some people have experienced allergic reactions when exposed to cyanoacrylate and epoxy glues. This is very rare. However, it is always important to use such glues, as well as paints, thinners, solvents, etc., with adequate ventilation to minimize and/or eliminate fumes.

Sanding Blocks And Straight Edges

It has been correctly said that the difference between a good model and a great one is sandpaper and the knowledge of how to use it. In these instructions you will note that we often mention sanding blocks , T-bar sanders , etc. You will definitely need several sanding blocks to build this model. If you don t already have one, do yourself a favor and purchase a T-Bar sander for this project and your shop. We also suggest that you make some sanding blocks of your own in various sizes. Use 3M 77" Spray Cement to attach the sandpaper to the sanding blocks and T-bar sanders. When the sandpaper gets tired use a heat gun to remove the old sandpaper and attach new. We suggest using 80 grit sandpaper during general construction, switching to 220 or maybe 360 for final sanding, before covering.

In addition to sanding blocks you will need several good straight edges to build this model. One of these should be at least 24" long, preferably 36" .

Laser Cut Sheets ( See Diagram )
1Sheet No.1; 1/4"x4"x6" Plywood F-1 Firewall & Landing Gear Mount 1Sheet No.2; 1/8"x4"x18" Plywood Servo Tray, F-2, Pant Mounts & Forward Hatch Mount 1Sheet No.3; 1/8"x4"x36" Balsa F-4, F-5, F-6, FB-1, FB-2 & FTR 1Sheet No.4; 1/8"x6"x36" Lite Ply Tank Floor, F-7, Hatch Base, APG, Fuse Hardpoint Doubler, Canopy Hatch Former, W-1 Rib (2), Canopy Hatch Guage, F-4 Cap
2Sheet No.5; 1/8"x4"x48" Balsa Fuselage Side 2Sheet No.6; 3/32"x4"x24" Balsa Fuselage Doubler 1Sheet No.7; 1/8"x4"x36" Balsa FB-3 & FSM Stab Mount 1Sheet No.8; 3/32"x4"x24" Balsa F-4T, F-5T, F-6T, F-3, F-2T, Canopy Hatch Sheet & Top Tank Sheet
1Sheet No.9; 1/4"x4"x18" Balsa S-2, S-3 1Sheet No.10; 1/4"x4"x30" Balsa S-1, VF-1, VF-2, VF-3, R-1, R-2, R-3 & R-4 1Sheet No.11; 1/4"x4"x24" Balsa E-1, E-2, E-3, E-4 & E-5 2Sheet No.12; 1/4"x4"x24" Balsa A-1, A-2, A-3, A-4 & Fin & Stab Fillers
1Sheet No.13; 1/8"x4"x24" Plywood W-1A Ribs (2) 1Sheet No.14; 1/8"x4"x24" Plywood W-2 Ribs (2) 1Sheet No.15; 3/32"x3"x24" Balsa W-3 Ribs (2) 1Sheet No.16; 3/32"x3"x24" Balsa W-4 Ribs (2)
1Sheet No.17; 3/32"x3"x24" Balsa W-5 Ribs (2) 1Sheet No.18; 3/32"x3"x24" Balsa W-6 Ribs (2) 1Sheet No.19; 3/32"x3"x24" Balsa W-7 Ribs (2) 1Sheet No.20; 3/32"x4"x18" Balsa WT Ribs (2)
Sheet Balsa
61/16"x4"x24" Wing Leading Edge & Center Section Sheeting 41/16"x1-1/2"x24" Wing Trailing Edge Sheeting


Stick Balsa
71/4" Sq. x24" Wing Spars & Turtle Deck Spine 41/4" Sq. x11" Wing Spar Doublers 41/16"x1/4"x36" Cap Strip Stock 21/8"x1/4"x36" Fuselage Stringer Stock
11/4"x1/2"x12" Vertical Fin Tailpost 13/16" Sq. x24" Hatch Locating Rails 13/16"x1/4"x24" Hatch Sides
Special Cut Balsa
23/8"x3/8"x24" Quarter Round Leading Edge 11/2"x12" Triangle Stock - Landing Gear & Firewall Support 23/4"x6" Fuselage/Fin Filler Blocks - Diagonal Cut 103/32"x4"x1-3/4" Vertical Grain Wing Shear Web Stock
25/16" Dia. x1" Dowel Center Drilled Hardpoint Stock, 1/8" I.D. 11/8" Dia. x1" Dowel Rear Hatch Attachment 13/16" Dia. x6" Dowel Rear Wing Root Locator
Wire Parts
11/8" Dia. Steel Wire Pre-Formed Elevator Joiner 11/16" Dia. Steel Wire Pre-Formed Tailwheel Wire 102-56 x10" Steel Wire Threaded One End Control Rods 1 .065 Dia. x18" Cable Braided Throttle Cable
Molded Parts
1Set of Plastic Wheel Pants (2 rights, 2 lefts) SIGSH378 1Nylon Throttle Cable Tube - 1/8"O.D. x18" 3Nylon Antenna, Rudder & Elevator Pushrod Tubes - 1/8"O.D. x30" 2Nylon Rudder & Elevator Pushrod Housing Tubes - 19/64"O.D. x30"
2Nylon Control Horn - Rudder & Elevator - Medium, Right 1Nylon Control Horn - Aileron - Small, Right 1Nylon Control Horn - Aileron - Small, Left 14-40 x1" Nylon Bolt - Forward Hatch Hold-Down
1Set of .40 Motor Mounts - SIGEM001 5Nylon 2-56 RC Links - Rudder & Elevator (2), Ailerons (2) & Throttle (1) 1.040 Clear Plastic Canopy
92-56 Solder Links - Tail Supports (4), Ailerons (2), Rudder & Elevator (2), Throttle (1) 42-56 Threaded Metal Clevises - Tail Supports 12-56 x3/4" Threaded Brass Coupler - Throttle Linkage 42-56 x3/8" Round Head Bolt - Tail Support Attach
42-56 Hex Nut - Tail Support Attach 12-56 Blind Mounting Nut - Tail Support Attach 44-40 x3/8" Round Head Bolts - Wheel Pant Attach 54-40 Blind Mounting Nuts - Wheel Pant & Forward Hatch Attach
2J-Hooks, Threaded - Wing Attach 36-32 x1/2" Round Head Bolts - Landing Gear Attach 46-32 x3/4" Round Head Bolts - Motor Mount Attach 26-32 x1-1/2" Round Head Bolt - Wheel Axles
46-32 Lock Nuts - Wheel Axle Assembly 26-32 Hex Nuts - Wheel Axle Assembly 76-32 Blind Mounting Nuts - Landing Gear & Motor Mount Attach 8#2 x1/2" Pan Head Screws - Control Horn Attach
6#6 Metal Washers - Wheel Axle Assembly 1Piece of 1"x8" Fiberglass Tape 18SIG Easy Hinges - Ailerons (8), Elevators (6), Rudder (4)
Miscellaneous Parts
17/8 O.D. x15-1/4" Aluminum Tube - Wing Joiner 1.880 I.D. x16" Phenolic Impregnated Tube - Female Wing Tube Receptacle 1.092 Formed Aluminum Landing Gear 28-1/2 x9-3/4" Plain White Paper - Aileron Servo Lead Tube Material
1Decal Sheet 1Set of 38"x50" Plan Set - Sheet 1 of 2 & Sheet 2 of 2 1Instruction Manual

About The Building Sequence

The construction sequence provided in this manual has been designed to provide the finished components (wing panels, tail group, etc.) in the order that they will be needed to progress to the following steps. We understand that the quickest and most efficient method of putting a kit together is to usually work on several pieces at the same time. However, we have found that by using CA glue and accelerator and following these instructions, the builder can literally continue building for as long as he or she wants, without having to wait for anything! These instructions assume that the builder is following the sequence provided. It is therefore recommended that you follow the order of construction presented here to avoid later confusion. We suggest that you take the time to read through these instructions, with the plans in front of you, to familiarize yourself with the general layout of the model itself, it's individual parts and the way in which the model is assembled.

Before Beginning Construction

Any references to right or left refer to your right or left, as if you were facing forward in the cockpit.

To build this or any good flying model, you must have a truly flat building board with adequate size for this model. Models that are not built true simply will not perform as intended. Your building board can be a table, an old cored door, a workbench, etc. Whatever you choose for a work surface, it must be flat and true.


Cover the top surface of your building board with a large piece of "Celotex" or even foam insulation board, which will easily accept pins. Be sure to use plenty of pins or weights when building in order to hold assemblies firmly in place.

When building over full-size plans, always protect them with wax paper to prevent glue damage and parts sticking to the plans themselves.

When asked to mark on the parts themselves, do not use a ball point pen directly on the wood. Ink will invariably leach through your film covering material and could ruin the finish. Use a well sharpened #2 pencil for best results. Use a small piece of masking tape and a pen to identify each of the various laser cut parts. To do this, refer to the Key To Laser Cut Parts drawings. Note that the outlines of the actual laser cut parts themselves have been purposely interrupted at various points. This must be done to keep the parts in their appropriate sheets. Use a hobby knife and a sharp #11 blade to remove the parts from their sheets as they are required for each step. All parts included in this kit can be easily identified in the COMPLETE KIT PARTS LIST.




Note: The full size plan depicts both right and left wing panels from the TOP view. These wing panels are initially built directly over the plans and are not removed for the bottom sheeting until Step 12. These instructions assume you are building both wing panels at the same time.


In this step, you need to prepare several parts for the construction of both wing panels. Begin by locating four (4) 1/4" sq. x24" balsa sticks and four (4) 1/4" sq. x11" balsa sticks from the kit contents. These will become the top and bottom wing spars. Trim the four 11" sticks to a length of 10-5/8" each. Glue one the 10-5/8" pieces onto one end of one of the 24" spars to create a laminated spar. Repeat this procedure with the remaining three spars. Note that the laminated ends of each spar, now measuring 1/4"x1/2" cross-section, will be the inboard ends.
Next, locate the two (2) ply W-1 root ribs and remove the round fillers in each. Set the two larger, 15/16" dia. fillers from each rib aside, as these will be used to cap the female wing tubes.

Remove the 7/8" dia. x15-1/4" aluminum wing joiner tube from the 16 length of phenolic impregnated female tube. Use a fine-tooth razor saw or power jig-saw to carefully cut two 6 lengths of female tubing, setting aside the remaining 4 piece for later use in the fuselage. Carefully glue one of the 15/16" dia. ply fillers (just removed from the W-1 ribs) onto one end of each of the two 6 female wing tubes. Lightly sand the outer edges of these caps to match the outside diameter (O.D.) of the female wing tubes. Set these tubes aside for use in the following steps.


Pin the bottom laminated spar carefully in place over the plan, with the laminated end at the inboard location, flush with the outer face of the W-1A rib location. Pin the spar in place from the top to allow the pins to be removed after the top sheeting is in place. The 1/4 sq. laminated length should be sitting on top of the 1/4 sq. full span spar at this point. Use a straight edge to ensure the spar is positioned exactly straight over the plan for the full span of the panel.

BUILDERS TIP: When pinning ribs to your work surface, pin them in place through each side of the removable alignment/standoff tabs on the bottom rear.


From the laser-cut parts in your kit, locate wing ribs W-1A through W-7 and the two plywood aileron servo trays that fit between ribs W-3 and W-4. Check each rib to make sure that each of the laser cut holes are cleared out - vent holes, etc. Now is also a good time to make sure your aileron servos fit into the standard servo cut-outs provided in each of the ply servo trays. If required, trim these trays as needed to allow your servos to fit nicely. This is also a good opportunity to drill the aileron servo mounting screw holes into the trays. We suggest using a power drill for this operation and backing up the trays with scrap ply to avoid splintering. Once this is done, set the trays aside for later installation.

Glue the W-7 tip rib in place onto the spar. Use a 90 deg. triangle to make sure the rib is exactly upright and that it is in place exactly over the plan - pin in place. Glue W-6 and W-5 in place in the same manner - making sure they are exactly upright and over the plan. Pin these ribs in place as well. Glue rib W-4 in place onto the 1/4" sq. spar and against the outer face of the 1/4" sq. spar doubler. Glue W-3 in place. Apply glue to the two tabbed outer edges of the aileron servo tray, spread the W-4 and W-3 ribs a little and fit the servo tray in place into the slots provided in each of these two ribs. Close the ribs to capture the servo tray and pin the ribs in place to your work surface.


Glue ply rib W-2 in place, again using a triangle to ensure that it is exactly upright at 90 deg. and exactly over the plan. Ply rib W-1A is now glued in place over the spar.
IMPORTANT: Take your time and be careful installing this rib. To provide the correct relationship to the fuselage, W-1A must be positioned at 90 deg. upright and exactly lined up over the plan.


Temporarily install the top spar in place into each rib - do not glue. Lay a piece of balsa wing sheeting over the top spar and ribs and place weights (magazines, metal bars, etc.) on top of the sheeting to make sure the panel is flat to the building surface. Glue the 1/4" sq. x24" balsa trailing edge stock in place to the end of each wing rib. Pin or fixture in place, making sure it is correctly in position and straight. With the wing panel still weighted in place, glue the shaped 3/8"x24" leading edge in place into the notches at the front of each rib, rounded edge facing forward - pin or fixture in place.


6. Remove the weights, wing sheeting and top spar from the wing structure. Slip the previously made female wing tube receptacle in place through W-1A and W-2, leaving 1/8" exposed at the outer face of W-1A - do not glue in place yet. From the contents of your kit, locate the ten (10) pieces of 3/32"x1-3/4"x4" shear web stock. Note that the distance between the rib stations W-7/W-6 and W-6/W-5 are both greater than 4 . This requires that you glue two of the 4" shear webs together to create a single 8" length. This 8" length is then trimmed to fit between ribs W-7/W-6. The left over trimmed shear web piece is then glued to another 4" length and trimmed to fit between ribs W-6/W-5. The remaining shear web requirements are each less than 4" and no further grafting is required.

Beginning at the W-7/W-6 location, cut and fit a vertical grain shear web to fit exactly between the top and bottom spars and between each rib. Note that the shear webs are aligned with the front edges of the spars. Once satisfied with the fit, glue the shear web in place to the bottom spar and the ribs, aligned with the top spar location. Move to the W-6/W-5 location and fit and glue the next shear web in place. Repeat this procedure - including the aileron servo bay area between the W-4 and W-3 ribs - up to and in contact with the ply cap on the end of the female wing tube. When all shear webs are in place, remove the female wing tube for later installation.


Glue the top laminated spar in place into each rib and onto the top edges of the vertical grain shear webs. Use a straight edge and weights to make sure the spar is in place straight and flat.


Use a long straightedge to true the edges of a piece of the 1/16"x4"x24" balsa sheet, provided in your kit. With the edges straight, cut and fit the leading edge sheeting in place. Note that the rear edge of this sheet is trimmed to fit halfway across the 1/4" top spar, leaving the rear exposed by 1/8". This exposed spar provides gluing surface for the center sheeting and the cap strips. We have found the easiest way to glue the leading edge sheeting in place is to do it in two steps;
  1. Start with the leading edge glue joint, where it mates to the top rear face of the 3/8 leading edge. Apply a bead of glue along the entire length of the sheeting, on its front edge only. Fit the sheeting in place to the top rear face of the 3/8 leading edge stock while holding it up at about a 45 deg. angle. Spray this glue joint with accelerator.
  2. Now apply a bead of glue to each rib, from their leading edges back to the spar location. Then apply another bead of glue along the entire front half edge of the top spar. Uniformly press the sheeting down across the ribs and onto the spar (a long metal straightedge is perfect here). Use a straightedge and weight to hold the sheeting flat to the spar and spray the whole thing with accelerator.

BUILDERS TIP: Whenever applying glue to a long length of wood which must rest on top of another piece of wood - such as wing sheeting on top of a spar - it is important to minimize or eliminate glue oozing from the joint. Keep several pieces of scrap balsa wood handy to scrape along the glue joint, thereby removing most or all of the excess glue.


With the wing panel(s) still firmly in place on your building surface, the 1/4" sq. balsa trailing edge now needs to be beveled slightly to conform to the top rear curvature of the ribs. This is most easily handled with a long T-bar sander and 80 grit sandpaper.


Locate the 1/16"x1-1/2"x24" trailing edge sheet stock from your kit box. Use a long straightedge to slice both 24 edges perfectly straight. Lay the sheet in place on the wing panel with its rear edge lined up with the rear edge of the 1/4" sq. trailing edge. Hold it in place and mark its forward edge location onto the top of each rib with a pencil. Remove the sheet and apply a bead of glue to each rib from the mark just made back to the trailing edge. Add a bead of glue along the entire top surface of the trailing edge. Carefully position the trailing edge sheet back in place and secure with pins or weights.


11. The two (2) pieces of 1/16"x4"x24" balsa sheet stock provided in your kit are now used to make the center section sheeting for both the top and bottom of both wing panels. Begin by using a straightedge to slice the edges of these sheets exactly straight. Then measure and cut the sheets into four (4) 6" lengths. Now carefully glue two of these 4"x6" sheets together along their 6" edges to create a single 6"x8" piece of sheeting. Repeat this process with the remaining pieces of sheeting. When finished, you should have four (4) pieces of 6 x 8 center section sheeting.

Fit one of the center section sheets in place against the rear edge of the forward wing sheet, with its adjacent edge lined up with the outer face of W-1A. If necessary, use a pencil to mark any trim that may be needed to align this edge with W-1A. Remove the sheet and use a straight edge to trim it. Reposition the sheet in place to check your work. Once satisfied, use a pencil to mark the sheet where it needs to be trimmed to mate to the front edge of the trailing edge sheeting. Do this very carefully to create the best possible fit. Trim the sheet to the marks just made and reposition the sheet in place. The front and rear should be almost seamless and the W-1A edge perfectly aligned.

Remove the center section sheet and use a straightedge and pencil to lightly mark the location of the outboard edge of W-2 onto the back edge of the forward wing sheet and the front edge of the rear wing sheet. Place the center section sheeting back in place and align it carefully. Now transfer the marks just made at W-2 onto the center section sheeting and again remove it. Use a straight edge and pencil to connect the two marks just made. Now use a circle guide or the plans to draw the corner fillets onto the sheeting. Use a straight edge and a sharp #11 blade to now trim the center section sheet to the shape shown on the plans, including the front and rear fillets. Lightly sand as needed to blend everything in and test fit the sheet in place. Once satisfied, glue the sheet in place to the forward and rear wing sheet edges, W-1A, W-2, and the exposed back half of the spar. Carefully position this sheet to minimize high spots, gaps, etc. Use weight or pins to secure in place and spray with accelerator.

BUILDERS TIP: When edge gluing two pieces of sheeting off the structure, it is always best to sand the resulting joint smooth on both sides with a sanding block before gluing the sheet in place. This practice minimizes high and low spots, bumps, etc.


Locate two of the four pieces of 1/16"x1/4"x36" balsa cap strip stock provided in your kit. Use this material to now add the rib cap strips to W-6, W-5, W-4, and W-3. These should be carefully centered on each rib and glued in place to avoid high spots, bumps, etc. As shown on the plans, the cap strip over the W-7 tip rib is glued in place with its outer edge flush with the outer face of W-7. Both wing panels can now be removed from your work surface.


With the wing panels now free from the work surface, carefully inspect your work thus far. Use a long T-bar sander and 80 grit sandpaper to carefully smooth the entire top surface of each wing panel. Do not use a small sanding block as this can cause dips and flats on the wing surface. The goal is to only smooth any rough areas, not to do the final sanding. Also lightly sand the face of W-1A to smooth any of the top sheeting that may be hanging over its top edge. Turn the panels over and use your hobby knife to carefully remove each of the stand off tabs on each rib. Place the panels back on your building surface with the unsheeted bottom sides up. Insert the female wing tube receptacle through W-1A, W-2 and up against the vertical grain shear web. Apply glue around each tube/rib joint on the inside of the wing only. Also apply glue to the area where the tube s ply cap contacts the shear web.

Locate the two (2) pieces of plain white paper, measuring 8-1/2"x9-3/4", from your kit. As shown on the plans, one of these sheets is rolled to form a tube 9-3/4" long. This tube is then inserted into the hole in W-1A, located just behind the female wing receptacle tube. Slip it through W-2 and just into W-3. This paper tube will be the aileron servo lead housing. Properly in place, the inboard end of the paper tube should be 1/8 proud of W-1A, like the female tube joiner receptacle. Apply glue to each tube/rib joint on the inside of the wing only.


14. IMPORTANT: Note that with the bottom sheeting not in place, the wing panels are not yet rigid and may be easily twisted. Once the bottom sheeting is in place, the panels are essentially locked in shape. Therefore, it is very important to properly support the wing panels during this step. We suggest using a length of wood at least 24" long and 1" wide to slip under the trailing edge of the panel, raising the trailing edge about 1" off your work surface. Using this fixture, the wing panel should be laying flat over the top spar location, supported at the trailing edge. Be sure that the 1" wide piece of wood is in full contact with the full span of the wing panel. This will avoid sheeting induced warping. Once the wing is in the correct position, use pins or weights to hold it firmly in place to the work surface and the 1" stand-off.

Using the 1/16"x4"x24" balsa in your kit, the bottom leading edge sheeting is now cut to fit and glued in place exactly as the top leading edge sheeting was in Step 8. Using the 1/16"x1-1/2"x24" balsa in your kit, the trailing edge sheet is now cut to fit and glued in place as it was in Step 10. Last, the center section sheeting, using the two remaining pieces of 1/16"x6"x8" balsa sheet, made earlier in Step 11, are cut to fit and glued in place in each wing panel.


Unlike the cap strips over the W-3 and W-4 ribs on the top of the wings, the bottoms must take into account the aileron servo bays and access to them. As shown on the plans, we simply used two (2) 1-5/16" lengths of the 1/16"x1/4"x36" balsa stock provided, to create a forward and rear servo bay opening on the bottoms of these two ribs. Once these two pieces are glued in place, simply cut, fit and glue the remaining cap strip material to cover the W-3 and W-4 rib bottoms, including the spaces between the servo bay cross pieces. The remaining exposed ribs are now covered with cap strips, exactly like the top of the wing panels.


Remove the wing panels from your work surface and use a sanding block to smooth the outer surfaces of the W-7 ribs. Glue the WT tip cover rib in place to W-7, aligning its edges carefully to the contours of the wing. Sand the face of W-1A smooth, avoiding contact with the two exposed tube ends. Trial fit the ply W-1 rib in place to W-1A. NOTE: When the W-1 rib is in place, with the female wing receptacle tube inserted into its corresponding hole, the rear 3/16" dia. wing locating dowel holes (in both W-1 and W-1A) will line up exactly. Use the 3/16 dia. dowel in your parts bag as a temporary fixture to maintain this relationship while gluing W-1 in place to W-1A and remove it when W-1 is attached. Glue W-1 in place, making sure it is flat against W-1A and firmly in place. Wipe off any excess glue.


As in Step 13, sand the bottom surfaces of the wing panels smooth, using a long T-bar sander and 80 grit sandpaper. Use compressed air and/or a tack rag to remove all dust particles from the wing panels and closely inspect them. Use a good quality, lightweight wood filler - such as "Model Magic" - to fill any nicks, dings or small voids. Finally, use your long T-bar sander and 220 grit sandpaper to lightly sand the wing panels smooth.


Locate the two threaded metal J-Hooks from the hardware in your kit. As shown on the plans, one of these hooks is screwed into each wing panel, at the root, just forward of the wing tube joiner location - the W-1 ribs each have a laser cut guide hole for these hooks. When the model is finished, the wing panels will be held in place to the fuselage by a single #64 rubber band, stretched between these two hooks. It is therefore important that the hooks be free of any burrs which might nick or cut the rubber band. Use a "Dremel" Tool and a carbide cut-off wheel to smooth the hook ends of each J-hook, eliminating any burrs. Thread the J-hooks into the W-1 root ribs, leaving about 9/16" exposed, with the open end of the hook facing forward. Leave the hooks in the wing panels for now but do not glue or permanently attach them yet.


The following instructions assume that both the left and right ailerons are built at the same time.


From the laser cut parts in your kit, locate aileron parts A-1, A-2, A-3, and A-4 - two each of all four parts are required. Cover the plans with wax paper and lay aileron leading edge part A-2 in place - pin or weight securely. Glue aileron trailing edge part A-1 in place to A-2. Glue aileron root cap A-3 in place, followed by aileron tip A-4.


20. Remove the completed ailerons from your work surface. Both ailerons should now be sanded smooth. Use a long T-bar sanding tool and 80 grit sandpaper to smooth both sides and the leading and trailing edges of each aileron (80 grit cuts quickly, so don t over do it). Now carefully inspect each aileron for nicks, dings, etc. Use a light filler, such as "Model Magic", to patch any problem areas. Once the filler has set, again use the long T-bar sander, with 220 grit sandpaper, to sand each aileron completely smooth.


As shown on the plans, the leading edges of the ailerons are chamfered 45 deg. to allow the extreme aileron and flaperon travel typically used on this design. The quickest and easiest way to do this is to use a pencil to draw a center line on the face of the leading edge of the aileron. Next, mark a point at one end of the aileron, 1/8" behind the leading edge. Make another mark at the other end of the aileron, again at 1/8" behind the leading edge. Use a straightedge and pencil to connect the two marks, giving you a pencil line 1/8" behind the leading edge and parallel with it. Do the same thing to the other side of the aileron. Use a long T-bar sanding tool and 80 grit sandpaper to uniformly sand the corners off the ailerons leading edge at a 45 deg. angle. As you sand, adjust the angle of the T-bar to eventually meet the centerline and the line behind the leading edge. When satisfied, turn the aileron over and repeat the process. When complete you should have a uniformly angled leading edge on each aileron.


As shown on the plans, each aileron is hinged to its wing panel with four (4) Easy Hinges. Using the plans, mark the location of each hinge onto both the ailerons and the wing panels. With a hobby knife and a #11 blade, cut each required hinge slot into the ailerons and wing panels. The slots need to be at least 1/2" deep and wide enough to accept the Easy Hinges. Trial fit a hinge into each slot to assure a good fit. Trial fit each aileron in place to its appropriate wing panel. When satisfied, remove the ailerons and set the hinges aside for later use after the wing panels are covered.


From the parts bag in your kit, locate the 1"x8" length of fiberglass tape. As shown on the plans, cut four (4) pieces of fiberglass tape measuring 1/2"x3/4". These will be placed over the laser cut aileron control horn holes, top and bottom, to reinforce these areas. Lay the cut piece of fiberglass in place over the holes and flood the tape with thin CA glue until the weave is full. Allow to set and repeat the process with the other side of the aileron. Repeat the process on the remaining aileron. Use sandpaper to lightly sand the glass smooth.

BUILDERS TIP: After cutting the fiberglass to the right dimensions, hold the piece with a pair of tweezers or hemostats and lightly spray one side with 3M 77" spray cement. The glass will then stay in position on the wood, ready for CA.

Stabilizer, Fin, Elevators And Rudder


Beginning with the stabilizer, locate part numbers S-1, S-2, and S-3 (2 each). Pin or weight S-1 securely in place over the plan, carefully lining up its rear edge with the drawing. Apply glue to the rear edge of S-2 and position it in place to S-1 - weight or pin in place and wipe off any excess glue. Glue an S-3 tip to each side of the stab assembly and pin or weight in place.


With the stabilizer still in place on your work surface, the elevator halves can now be built. Locate laser cut part numbers E-1, E-2, and E-3 (2 each) and also E-4 and E-5. Protect the stab from glue with a strip of wax paper along its rear edge. Position part E-2 in place against the back edge of the stab, directly over the plan - pin or weight in place. Apply glue to the front edge of E-1 and glue it in place to the back edge of E-2 - weight or pin in place and wipe off any excess glue. Glue elevator tips E-3 in place to the ends of the E-1/E-2 assembly. As shown on the plans, glue E-4 in place to the left elevator half at the inboard edge of the E-1/E-2 assembly. Glue E-5 (with the laser cut elevator horn holes) to the right elevator half, on the inboard side of the right E-1/E-2 assembly.


Remove the elevator halves from your work surface. From the parts bag provided in your kit, locate the pre-bent 1/8" dia. wire elevator joiner. As shown on the plans, this joiner fits into each elevator half. Use a pencil to mark the location of the required 1/8" dia. holes that must be drilled into the leading edge of each elevator half to accept the wire joiner. To best control the centering of these holes, we suggest using a non-powered twist drill. Make each hole 1" deep and at 90 deg. to the leading edge of the elevator halves. The leading edges of the elevator halves, from the just drilled holes, inboard through the E-4 and E-5 parts, must now be grooved to accept the 1/8" dia. wire joiner.


This is easy to do using a hobby knife and a #11 blade. A Dremel Tool and a carbide cut-off wheel may also be useful in this step. Once the elevator halves are grooved, trial fit them together with the wire joiner. Adjust the grooves and holes as required to achieve a good fit. Mix a small amount of 5-minute epoxy and apply glue into each hole and channel in both elevator halves. Clean the joiner with acetone and Install it in place into each elevator half, wiping off any excess epoxy. Lay this assembly onto your wax paper protected plans, with the leading edges firmly against a straight edge and pin or weight in place. Allow the glue to cure before removing the elevators from your work surface.


The vertical fin and rudder are built in much the same manner as the stab and elevators. From your laser cut parts, locate the VF-1, VF-2, and VF-3 parts for the fin and the R-1, R-2, R-3, and R-4 rudder parts. Also locate the 1/4"x1/2"x12" balsa tailpost, used for the trailing edge of the fin. Cover the plan with wax paper. Cut the 1/4"x1/2" tailpost to the length shown on the plans (save the left over piece for use as a spacer during fuselage construction) and pin it in place, directly over its location on the plan - note that the tailpost extends down through the rear of the fuselage, to the top surface of the ply hardpoint doubler. Glue VF-1 in place to the forward edge of the tailpost.


Protect the rear edge of the tail post with wax paper and use weights or pins to hold R-1 in place against it. Glue R-2 in place to the rear edge of R-1. Glue R-3 in place to the top of the R-1/R-2 assembly and glue R-4 in place to the bottom.


From your parts bag, locate the two 1 lengths of 5/16" dia. center drilled wood dowels. These will be used to make the hardpoints in the stab (2 each) and the fin (1 each), the rest will be used in the fuselage. Insert one of these dowels into the laser cut hole in the fin so that it bottoms out on the other side. Mark the dowel with a pencil, remove it from the fin and use a razor saw to cut off the piece just marked. Glue the dowel piece into the hole in the fin. Repeat this procedure with the two holes on each side of the stab. Save the excess drilled dowel material as it will be used during fuselage construction.


The tail group is now basically assembled. We suggest that now is a good time to sand these assemblies. In order to sand the fin/rudder and stabilizer/elevators assemblies uniformly, use masking tape on one side only to temporarily attach the rudder to the fin and the elevators to the stab and then sand the opposite, untaped sides. Once the sides are smooth, add tape to the now sanded sides, turn the parts over, remove the tape and sand those sides smooth. To begin, use a large sanding block with 80-grit sandpaper. This very quickly smooths these flat surfaces, so don t over do it. Once the surfaces are smooth on both sides and their edges, switch to 220 grit paper to achieve a very smooth surface.


Like the ailerons, the leading edges of the rudder and elevators are now be sanded to shape. As shown on the plans, these leading edges are beveled to create a 45 deg. angle, top and bottom from the center line. This angle allows for the extreme surface travel used on this design. Follow the directions in the Aileron section, Step 21, to achieve these required hinging angles.


The leading, trailing and tip edges of the fin/rudder and stab/elevators can now be sanded to shape as shown on the plans. Note that we did not overly shape or airfoil these edges but rather simply rounded them. To ensure uniformity, sand these parts with the rudder taped to the fin and the elevators taped to the stab.


From the parts bag in your kit, locate the pre-bent tailwheel wire. As shown on the plans, the tailwheel wire is embedded in the forward bottom edge of the rudder. Using the plans as a guide, drill a 1/16" dia. hole in the bottom of the rudder to accept the tailwheel wire arm - about 1/2" deep. Again, we would suggest using a simple twist drill to do this. Once the hole has been made, use your hobby knife and a #11 blade to cut a 1/16" wide channel in front of this hole, allowing the tailwheel wire to nest in place. Trial fit the wire and adjust the channel and hole as required to achieve a good fit. Clean the wire part with acetone. Mix a small amount of 5-minute epoxy and glue the tailwheel wire in place into the bottom of the rudder. Wipe off any excess glue and allow to cure.


34. Using the fiberglass tape provide in your kit, cut four 1/2"x3/4" pieces. These are glued in place over the rudder and elevator control horn holes with thin CA glue. Next, cut two pieces of fiberglass tape to fold over each of the elevator/joiner wire joints, as shown on the plans, again using thin CA glue. Last, cut a piece of fiberglass tape to fit over the tailwheel wire/rudder location, as shown on the plans. Affix in place with thin CA glue.


As shown on the plans, the fin and rudder will be hinged with four (4) hinges and the stab and elevators will be hinged with a total of six (6) hinges - three per side. Using the plans, mark the hinge locations onto each part with a pencil. Use a #11 blade and your hobby knife to cut hinge slots into each hinge location. These must be at least 1/2" deep and wide enough to accept the Easy Hinges provided in your kit. Each time you complete a hinge slot, trial fit a hinge in place to assure a good fit. When all slots are cut, trial fit the fin and rudder together. Do the same with the stab and elevators. Set the hinges aside for use after the parts are covered.

With the exception of notching the fin tailpost for clearance of the elevator joiner - done during fuselage construction - the tail group should now be complete, sanded and ready for assembly during the construction of the fuselage.


Before starting fuselage construction, there are several subassemblies that should be built and set aside until needed. This is done to avoid interrupting the sequential flow of the fuselage construction. These preliminary subassemblies involve the 1/4" plywood F-1 Firewall, the 1/4" ply Landing Gear Mount and the 1/8 ' ply Forward Hatch Mount. In addition you will also need the following hardware provided in your kit; seven (7) 6-32 blind mounting nuts, four (4) 6-32 x3/4" round head slotted bolts, one (1) 4-40 blind mounting nut and two (2) glass-filled engine mounts. You will also need the engine you plan to use available to you for the following steps:


  1. Use the laser cut vertical and horizontal centerline reference marks at the edges of the F-1 firewall to draw a vertical centerline and horizontal thrust line onto the fire wall.
  2. Determine the required spacing between the two engine mounts to fit your particular engine. Use a pencil to mark that spacing onto the face of the firewall. (Example: If the width of your engine s case is 1-3/8", then divide that figure in half (11/16" ) and mark the face of the firewall with the 11/16" measurement on each side of the vertical centerline. Use a triangle to draw two parallel lines, one at each 11/16" point, thus giving you the centered location for each motor mount arm.
  3. To temporarily hold it in place, apply a drop or two of CA glue to the back of one of the motor mounts and place it onto the firewall, lining up its inside edge to the line drawn in b. above and the laser cut top and bottom bolt holes. Insert the bolts into the holes in the front of the mount arm and through the firewall. Thread the blind nuts partially onto the ends of the bolts at the back of the firewall. Carefully apply thick CA to the outer surface of the blind nuts and use a screwdriver to tighten the bolts, thus drawing the nuts firmly into the back surface of the firewall. Repeat this process for the remaining motor mount arm.


Place your engine onto the two motor mount arms, still bolted to the firewall. Hold this assembly over the plans to determine the mounting position of your engine, allowing the prop/spinner to clear the fuselage sides at the nose. Mark this position on the motor mount arms. Holding your engine in place on the mounts, use a pencil to mark the locations of the four required engine mounting holes onto the mount arms. Remove your engine. Use a power drill with a 9/64" dia. drill bit to now drill the four bolt holes through the motor mounts at 90 deg. Your engine can now be mounted in place when the time comes. Remove the bolts and motor mounts from the firewall.


Apply thick CA glue to the outer surface of one of the 6-32 blind mounting nuts and position it in place into one of the holes in the 1/4" ply landing gear mount. Use a hammer to lightly tap the blind nut in place into the wood. Repeat this step for the remaining two blind nuts. Set the mount aside for later assembly.


Apply thick CA glue to the outer surface of the 4-40 blind mounting nut and position it in place into the hole in the center of the 1/8" ply forward hatch mount. Use a hammer to lightly tap the nut into the wood. Set the mount aside for later assembly. This completes the fuselage subassemblies.