Sig Mfg. Co., Inc....401-7 South Front Street....Montezuma, Iowa 50171


The SEALANE takes off and lands on water just as easy as the Sig Kadet LT40 does on solid ground. Gentle, graceful, sure footed. However, once the bond has been broken between plane and pond, the SEALANE roars to life with a performance not to be missed. Loops, rolls, inverted flight; all at your fingertips. Water handling characteristics are very positive, even in cross winds. It's the perfect choice for your first seaplane adventure. And although the SEALANE is no landlubber, there is an optional fixed landing gear design for adventures off water down at the local field.

This assembly manual has been specifically sequenced to get your SEALANE assembled and into the air very quickly. We strongly suggest that you read through the manual first to get familiar with the various parts and their assembly sequences. The proper assembly and flying of this aircraft is your responsibility. If you are new to the sport/hobby of radio control, we urge you to seek the assistance of a qualified person to help you assemble this model airplane. If you do not understand a particular assembly step or sequence, do not guess - find qualified help and use it.

Radio Equipment

The SEALANE requires a standard 4-channel radio system and four standard servos. We have used and can highly recommend both the Hitec™ and Airtronics™ systems. Both of these very affordable and reliable radio systems offer all the features you’ll need for this and the many other R/C aircraft in your future. For reference, this assembly manual shows the installation of a Hitec™ radio system with standard servos. The standard 6" aileron servo extension that comes with the radio system will be used but you will not need any additional radio accessories.


Engine Selection

Engine choices for the SEALANE are many. The SEALANE has been designed to produce excellent performance when using the recommended engine sizes. Do not use an engine larger than recommended.

2-stroke engines are a perfect choice to power your SEALANE. Any plain-bearing or bearing equipped .40 to .45 sport engine would be a good choice. For example, a great choice would be the Irvine .40 engine. Like all Irvine engines, the .40 is powerful, reliable, and quiet. Whatever engine you choose, take the time to carefully break it in according to the manufacturer’s instructions. A good running, reliable engine is a minimum requirement for the enjoyment of this or any R/C model aircraft.

The SEALANE can also use a variety of 4-stroke engines. Any 4-stroke engine in the .40 - .50 displacement range should provide plenty of power. An important thing to remember is that typical 4-stroke engines have their throttle arms usually located differently than throttle arms on 2-stroke engines. If you want to power this model with a 4-stroke engine, you will likely have to install a new, relocated throttle cable tube. While this is not difficult, it is something to consider when choosing an engine.

Covering Material And Waterproofing

Your SEALANE has been designed to be completely covered with any of the popular plastic iron on covering materials on the market. These covering materials are waterproof and by carefully overlapping the seams approximately 3/32", your SEALANE will be almost waterproof.

The only place on the model where water can enter the fuselage is at the joint where the wing attaches. Our prototype models were made with relatively tight fitting wings, with no additional sealing, and very little water was able to enter the fuselage.

Required Tools

A selection of glues: A selection of hand tools, such as:
  • Sig Thin CA
  • Sig Medium CA
  • Sig thin CA applicator tips
  • Sig Kwik-Shot Accelerator
  • Sig Epoxy Glue (15 Minute Working Time)
  • Regular size and miniature screwdrivers
  • Regular size and miniature pliers
  • Tweezers or small hemostats
  • Hobby knife with several new #11 blades
  • Sandpaper-assorted grits
  • Sig Modelers “T” pins
  • Drill Motor
  • 1/16” Drill Bit
  • 3/16” Drill Bit
  • 1/4” Drill Bit
  • Covering Iron
  • Wax Paper
  • Fuel Proof Paint
  • Small Paint Brush
  • Razor saw or Hacksaw blade
  • Pencil
  • Small 90° Square
  • Masking tape and Rubber bands

Laser Cut Parts
There are 13 Laser Cut Sheets included in this kit. Use the illustrations on the following pages to identify these parts.
Wooden Parts
QtyAssemblyNameSize & Material QtyAssemblyNameSize & Material
1FuselageFuse Nose Top Stringer1/4”x1/4”x13” Balsa Stick 2FuselageFuse Nose Top Sheet3/32”x3”x13” Balsa Sheet
28FuselageFuse Bottom Sheet3/32”x3”x3” Balsa Sheet 1FuselageWindshield Top Block1”x1”x4-1/2” Balsa Block
1FuselageNose Block4”x2-3/4”x3” Balsa Block 1FuselageWindshield Top Sheet3/32”x1-3/4”x4-1/2” Balsa Sheet
1FuselageFuse Aft Bottom Block1/4”x2-1/2”x6” Balsa Sheet 2FuselageBolt Block & Firewall Reinf1/4”x1/4”x7” Balsa Triangle
2FuselageServo Tray Support1/4”x1/4”x5-1/4” Balsa Stick 1FuselageSwitch Wire Guide1/4”x1/4”x1” Spruce Stick
4WingMain Wing Spars1/4”x1/4”x30” Spruce 2WingTrailing Edges1/4”x1/4”x30” Balsa Stick
4WingTrailing Edge Sheet3/32”x1”x30” Balsa Sheet 2WingLeading Edges3/8”x3/8”x27” Balsa Stick
2WingLeading Edge Sheet3/32”x3”x30” Balsa Sheet 2WingLeading Edge Sheet3/32”x3 1/8”x30” Balsa Sheet
8WingCenter Section Sheet3/32”x3”x12” Balsa Sheet 4WingCap Strip Material3/32”x1/4”x36” Balsa Stick
2WingWing Tip1-1/2”x1-1/2”x11-1/2” Balsa Triangle 4WingTip Float Anchor1/2”x15/16”x1.15” Hardwood


Wooden PartsContinued
QtyAssemblyNameSize & Material QtyAssemblyNameSize & Material
2WingWing Dowel1/4"x1" Birch Dowel 2WingWing Bolt Plate1/32"x3/4"x1-1/4" Birch Ply
2WingAileron440”x1-1/2”x25” Balsa Trailing Edge 2WingTorque Rod Bearing Block440”x1-1/2”x3-29/32” Balsa Trailing Edge
4WingServo Rails1/4”x1/4”x1-1/4” Spruce Stick 18WingShear Webs3/32”x2-7/8”x1-5/32” Balsa Sheet
2Tip FloatTip Float Leading Edge1/4”x1-3/4”x4-3/4” Balsa Sheet 2Tip FloatTip Float Trailing Edge1/4”x1/4”x6” Balsa Stick
12Tip FloatTip Float Sheet1/16”x3”x7” Balsa Sheet 3PylonPylon Sheet3/32”x3”x5” Balsa Sheet
1PylonPylon Tail Block4”x3-1/4”x4-3/4” Balsa Block 3PylonPylon Engine Fairing Sheet1/4”x3”x4-3/4” Balsa Sheet
1Tail SurfacesFin Gussets1/4”x1/4”x12” Balsa Triangle 1Tail SurfacesTail Surface Framework1/4”x1/4”x4” Balsa Stick.
2Tail SurfacesTail Surface Framework1/4”x1/2”x36” Balsa Stick 1Tail SurfacesTail Surface Framework1/4”x3/4”x36” Balsa Stick
1Tail SurfacesTail Surface Framework1/4”x1”x9” Balsa Stick 1Tail SurfacesTail Surface Framework1/4”x1-1/4”x21-3/4” Balsa Stick
QtyAssemblyNameSize & Material QtyAssemblyNameSize & Material
4Tip FloatTip Float Attach8-32 x1-1/2” Pan Head Nylon Screw 4Tip FloatTip Float Attach8-32 Blind Nut
1WingStrip Aileron Horn SetLeft & Right Torque Rods with Connectors 2WingAileron Pushrod2-56 Pushrod 3” Long
5Wing, Fuselage & PodClevisNylon 2-56 R/C Link 4Wing & FuselageClevis2-56 Solder Link
16Wing & Tail SurfacesHingeSig Easy Hinge 2FuselagePushrod Housings24” Nylon Pushrod Housing
2FuselagePushrod24” Nylon Pushrod 2FuselagePushrod End - Elev. & Rud2-56 pushrod 7” long
2FuselagePushrod End - @ Servos2-56 pushrod 1-1/2” long 1Tail SurfacesElevator JoinerBent 3/32” Music Wire
2Tail SurfacesNylon Control HornsSig Medium Control Horns - 1 Left & 1 Right 4Tail SurfacesControl Horns Screws#2 x1/2” Sheet Metal Screw.
2WingWing Attach Bolts1/4-20 x1-1/2” Pan Head Nylon Screw 1FuselageSwitch Pushrod3/64”x5” Music Wire
1PylonPushrod Connector BodyBrass Pushrod Connector Body 1PylonPushrod Connector Screw4-40 x1/8” Socket Head Screw
1PylonPushrod Connector RetainerMolded Nylon Retainer 1PylonThreaded Brass Coupler2-56 Brass Coupler
1PylonThrottle Pushrod HousingPushrod Housing 18” 1PylonThrottle Pushrod CablePushrod Cable 18”
Misc. Parts
QtyAssemblyNameSize & Material QtyAssemblyNameSize & Material
1MiscDecal Sheet1 Color Mylar Decal 1MiscFuselage Plan36”x48” Plan sheet A
1MiscWing Plan36”x48” Plan sheet B 1MiscInstruction ManualInstruction Manual
1MiscWindshield.015”x4”x8-1/2” Clear Plastic
Additional Items (Not included in Kit)
QtyAssemblyNameSize & Material QtyAssemblyNameSize & Material
1PylonMotor MountDave Brown Mount to Fit Engine Used 8PylonMounting Bolts6-32 x3/4” Socket Head Cap Screws
8PylonWashers6-32 Washer 4PylonBlind Nuts6-32 Blind Nut
1PylonFuel TankSullivan 8 oz. Round Fuel Tank 1PylonSpinnerSig 2-1/4” Spinner
1PylonFuel LineSig Medium Fuel Line 2AllCovering2 Rolls Iron On Covering + Trim Color
1PylonPropellerTo Fit Engine Used 1PylonEngine.40 to .46 2-cycle or .40 to .50 4-cycle
1AllRadio4-Channel Radio with 4 Standard Servos 2FuselageRadio Protection3/8”x3”x8” Foam Rubber
Optional Landing Gear Parts (Not included in Kit)
QtyAssemblyNameSize & Material QtyAssemblyNameSize & Material
2Main Landing GearMain Wheels3” Wheels 4Main Landing GearWheel Collars5/32” Wheel Collars


Optional Landing Gear Parts (Not included in Kit)Continued
QtyAssemblyNameSize & Material QtyAssemblyNameSize & Material
4Main Landing GearWheel Collars3/16" Wheel Collars 1Main Landing GearMounting1/8" Lite Plywood
1Main Landing GearCopper Wire.016 Soft Copper Wire 4Main Landing GearMain Landing Gear Legs3/16"x12" Music wire
2Main Landing GearMounting Tubes3/16” K&S Brass Tube #129 3TailwheelMounting2-56 x1/2” screws
3TailwheelMounting2-56 washers 3TailwheelMounting2-56 nuts
1TailwheelMounting1/32” Birch Plywood 1TailwheelMounting1/16” Birch Plywood
1TailwheelTail Wheel1” Wheel 1TailwheelWheel Collars1/16” Wheel Collar
1TailwheelAxle1/16”x6” Music Wire



General Building Notes

  1. The SEALANE is recommended for the modeler who has previous building experience. Although the SEALANE is an easy model to build and fly, the instructions were written assuming that the builder has previous experience. As such, procedures such as how to make a proper wood joint or detailed covering instructions are not covered.
  2. The first thing that you need to do is mark part numbers on the laser cut parts using the drawings for reference.
  3. The laser cut parts have small tabs that keep them attached to the main sheet. You should use your hobby knife to remove the parts from the sheets. If a part is not completely cut through you can use your hobby knife to free it from the sheet.
  4. The slight discoloration of the edges of the laser cut parts may be removed by lightly sanding them with 320 grit sandpaper.
  5. The wings and the tail surfaces are built directly over the plan. You should cover the plan with wax paper to protect it and to prevent the parts from sticking.



Cover the stabilizer and rudder plan with wax paper. Pin stabilizer parts S-1 and both S-2’s into position on the plan. Using the wood sizes on the plan, cut and glue in place the remainder of the stabilizer parts. Remove the stabilizer from the plan.


Pin and glue elevator parts S-3, S-4, and S-5 into position on the plan. Using the wood sizes on the plan, cut and glue in place the remainder of the elevator parts. Remove the elevator from the plan.


Pin fin parts R-1 and R-2 into position on the plan. Using the wood sizes on the plan, cut and glue in place the remainder of the fin parts. Remove the fin from the plan.


Pin rudder parts R-4 into position on the plan. Using the wood sizes on the plan, cut and glue in place the remainder of the rudder parts. Remove the rudder from the plan.


Sand the outside edges of the fin and rudder round. Bevel the leading edge of the rudder. Mark the hinge locations, cut the slots, and temporarily install the hinges (without glue). Set the fin and rudder assembly aside until needed later in construction.


Sand the outside edges of the stabilizer and elevators round. Bevel the leading edge of the elevators. Mark and drill the holes in the elevators for the 3/32" joiner wire. Cut a small channel in the leading edge just inboard of the holes for the joiner to fit into, allowing it to be flush with the leading edge. Mark the hinge locations, cut the slots, and temporarily install the hinges (without glue).

Set the stabilizer and elevator assembly aside until needed later in construction.


NOTE: The fuselage is built mostly from laser cut lite plywood parts. You will use the plan as a guide but the fuselage is not built over the plan.


7. Glue the fuselage doublers (F-2) to the inside of the fuselage sides (F-1). Be sure that you make a left and a right side.


Glue formers F-3 and F-5 into position on the right fuselage side. Use a small square to make sure that the formers are 90° to the fuselage side.


Place the left fuselage side into position on the formers and glue in place.


Glue formers F-4A and F-4B together as shown on the plan. Now slide the formers into position in the fuselage and glue in place. Gently squeeze the fuselage together at the front and place formers F-6 and F-7 into position. Carefully check to see that the front of the fuselage is not twisted and glue the formers into position.


Glue formers F-15A and F-15B together as shown on the plan. Now slide F-15 into position in the fuselage and glue in place. Place F-8 into position on the fuselage. Do this by sliding the tab in the front of F-8 into the notch in F-7 and then pivoting the back end down into position and glue in place.


Squeeze the back end of the fuselage together and hold with clothespins or small clamps. Tack glue formers F-9 and F-10 into position.


The rearmost end of the fuselage should be 90° to the fuselage top. Loosen the clamps and adjust if required. Now apply glue to bond the rear of the fuselage together.


Glue the keel (F-14) into the slots in the bottom of the fuselage formers. Align the step in the keel with formers F-4A and F-4B. The keel may extend slightly past F-7 and F-10. When the glue is dry, trim the ends of the keel flush with the formers F-7 and F-10.


Glue formers F-16, F-17, and F-19 into position. F-16 and F-17 should be centered left and right and 90° to F-8. F-19 should be 90° to F-3. Glue the 1/4” sq. balsa strip between formers F-7 and F-17. When the glue is dry, trim the balsa strip off flush with the front of F-7 and the rear of F-17.


16. Position the wing bolt blocks (F-18) in the fuselage assembly. The top edge should be 1/4" below the top edge of the fuselage side to make room for the 1/4” balsa triangle reinforcements. Glue the bolt blocks in place with epoxy. Cut the 1/4" balsa triangle reinforcements and glue into position.


Sand the front edge of F-11 so that it is flush with the front of F-12. Sand the proper angle on the bottom of F-20 and glue it into position on the front of F-12. When the glue is dry, trim the top edge of F-20 flush with the top of F-11.


Take one of the 3/32" top front balsa sheets and place into position on the fuselage as shown. The lower edge should touch the fuselage side and the other edge should stick up at an angle. When the sheet is positioned properly you can glue it to the fuselage.

When the glue is dry, thoroughly wet the outside of the sheet with an ammonia based cleaner such as Sig’s Pure Magic Airplane Cleaner. Allow it to soak in for about 10 minutes.


Using the palms of both hands, carefully bend and roll the sheet around the formers. Hold the sheet in position and mark and trim the inboard edge to the centerline of the 1/4" sq. balsa strip. Now glue the sheet into place.

NOTE: Depending on the grain and hardness of the sheet, you might find that several small splits open up in the lower edge as you are rolling the sheet into place. This is not a problem. After the sheet is installed, apply a small amount of thin C/A to the cracks and then fill them in with balsa filler such as Hobbico Hobbylite™ Filler and sand smooth.


Now fit, trim, and glue the opposite side top sheeting into place. When the glue is dry, trim and sand the front and rear edges flush with F-7 and F-17.


Using a gentle fore and aft motion, carefully sand the fuselage bottom so that the sides and keel match the angle of the formers.


Working from F-4 forward, glue the bottom sheet pieces into position. The inboard edge should be centered on the keel (F-14) and the outboard edge should extend past the fuselage side. The first four pieces should fit into position with out trimming the inboard edge. Because of the curvature of the nose of the model, the inboard edge will need to be trimmed to the center of the keel.


23. Working rearward from F-4 toward F-10, glue the bottom sheet pieces into position. The inboard edge should be centered on the keel (F-14) and the outboard edge should extend past the fuselage side. Glue the 1/4"x2-1/2"x6" balsa sheet to the bottom of the fuselage behind F-10. When the glue is dry, trim, and sand the bottom sheet flush with the fuselage sides.

Continue the "V" shape of the bottom all the way back to the aft end of the model by sanding the bottom of the rear 1/4" sheet.


Glue the nose block into position on the front of the fuselage. When the glue is dry, carve and sand the nose block to shape using the following steps. The first thing to do to shape the nose block is to draw the side profile onto the block as shown. Now trim the block to this outline. The outline should be slightly oversized.


Now draw the top profile onto the block as shown. Now trim the block to this outline. The outline should be slightly over size.


Sand the bottom of the block with a fore and aft motion to match the angle of the "V" on the bottom of the fuselage. You can draw a centerline on the block to assist you.

Finally, sand the top corners round and smooth the block all over.

Now sand the fuselage smooth all over.