KIT NO. FK-OOl SIG 46" FLOATS - GENERAL DESCRIPTION These floats are designed to work on any large radio-controlled model airplane weighing from 12 to 25 pounds. They could be used on models heavier than 25 pounds if the model isn't physically too large in size. The floats will support the heavier weight on the water quite easily. However, models over 25 pounds will usually be physically too large to handle well on this size of floats. As a general rule, the length of the floats should be about 2/3 to 3/4 length of the model's fuselage, give or take a few inches. These floats will work best on a model with a 62 to 70 inch long fuselage, having a 6 to 9 foot wingspan, weighing 12 to 25 pounds. The finished floats, including all the brace wires, mounting hardware, and water rudder, normally weigh about 3-1/2 pounds when all done. If your model's regular wheel landing gear weighs 1-1/2 pounds (as the Sig 1/4-scale Cub does) then the actual weight difference between the water and land configurations of your plane will be about 2 pounds. Models to be flown on floats must be amply powered to handle the extra weight and also extra drag. As a general rule, if your airplane can presently be safely flown in land configuration at 3/4 throttle or less, it will have enough power to fly with floats. The addition of these floats on a model should not change its balance point very much. The floats by themselves balance near their "step" (at former F5) when finished. If they are properly mounted on the model with the step located at the model's balance point, then the model shouldn't become either nose heavy or tail heavy because of the addition of the floats. PERFECT FIT ON A SIG CUB The pre-formed brace·wires and all of the mounting hardware in this kit are designed for mounting the floats on a Sig 1/4-scale Piper J-3 Cub or Sig Clipped Wing Cub. Those are the airplanes that the floats were originally designed for and tested on at our factory. Note that the fullsize plan shows the floats mounted on a Sig 1/4-scale Cub. Also, this instruction book describes every step involved in making the Sig Cub/float installation. If you intend to mount your floats on a Sig 1/4-scale Cub, everything you'll need is included in this kit. The only modification required to the model is the installation of another grooved I.g. block farther back in the fuselage to mount the rear brace wire in. It's a simple process to install the block even if your Cub is already covered and finished (see page 9). MOUNTING ON OTHER MODELS If you intend to mount your floats on other than a Sig Cub you'll probably have to modify, or possibly make all new brace wires to fit your particular airplane. Every airplane will be a little different, depending on the exact configuration of the bottom of the fuselage. Some models may need a taller front brace wire. Some models may need a taller rear brace wire. Some may need the spacing between the tops of the brace wires changed. Although the actual mounting won't come until after the floats are built and finished, it's a good idea to start planning for the installation now. Unfortunately, we cannot provide instructions or complete parts to cover every possible installation. You'll have to use your own ideas and ingenuity when mounting these floats on models other than a Sig Cub. See page 12 for more information. 2 GLUES We recommend that the floats be assembled with either epoxy glue (such as Sig Kwik-Set or regular Epoxy), or with cyanoacrylate "super" glue (such as Zap, Jet, or Hot Stuff). Do not use other glues unless you are sure that they will be waterproof when dry. CAUTION: Some people have experienced allergic reactions when exposed to epoxy or cyanoacrylate glues. This is very rare. However, it is always important that such glues, and also paints, thinners, and solvents, be used with adequate ventilation to carry fumes away. NOTES BEFORE BEGINNING CONSTRUCTION Any references to right or left refers to your right or left as if you were seated in the cockpit of the airplane. To build these floats you will need a good straight building board at least 45 inches long. The building board can be a table, a workbench, a reject "door core" from the lumber yard, or whatever - as long as it is perfectly flat and untwisted. Cover the top surface of the building board with a piece of celotex-type wall board or foam board, into which pins can be easily pushed. Don't hesitate to use plenty of pins during assembly to hold drying parts in correct position. When pinning and gluing parts directly over the full-size plans, cover the plan with wax paper or plastic kitchen wrap to prevent gluing the parts to the plans. Don't use a ball point pen for making marks on the model during construction. If not sanded off, these ink marks will show through the model's final finish. Use a pencil instead of a pen. Leave all the die-cut parts in the sheets until needed in construction. Remove pieces from the sheets carefully. If difficulty is encountered, do not force the part from the sheet. Use a modeling knife to cut it free. All of the other kit parts can be identified by the "COMPLETE KIT PARTS LIST" on page 14. Sort the different sizes of sticks and sheets into in- dividual piles to avoid confusion during building. Cut all long pieces of balsa first, followed by medium lengths, before cutting up any full length strips into short pieces. Any model parts mentioned in this book, but not furnished in the kit, are marked by an asterisk (*). SANDING BLOCKS An assortment of different size sanding blocks are indispensable tools for model construction. A good general purpose block can be made by wrapping a full 9" x 11" sheet of sandpaper around a piece of hardwood or plywood. Use three screws along one edge to hold the overlapped ends of the sandpaper. Put 80 grit paper on the block during general construction. Switch to 220 grit paper for final finish sanding just before covering. SANDING BLOCK 3/4" x 3" x 11" HARDWOOD BLOCK Another handy block can be made by gluing sandpaper onto a 24" or 36" long piece of aluminum channel stock. Most hardware stores carry a rack of aluminum in various sizes and shapes. This long block is very useful for sanding leading and trailing edges accurately. Finally, glue sandpaper onto different sizes of scrap plywood sticks and round hardwood dowels. These are handy for working in tight places and for careful shaping where a big block is too hard to control. 3 ................... .............................. ....................................... rr:f FRONT PLYWOOD DOUBLER "KEY TO DIE-CUT PLYWOOD PARTS" mtUZl l:illi:li:1 REAR PLYWOOD DOUBLER 111':'11::1 MARK PARTS IN KIT ACCORDING TO THESE DIAGRAMS FRONT PLYWOOD DOUBLER iYl~ 3/32" PLYWOOD 118" LITE-PLY 1 REQUIRED 2 REQUIRED 118" LITE-PLY 2 REQUIRED 118" LITE-PLY 118" LITE-PLY 1 REQUIRED 2 REQUIRED 118" LITE-PLY 2 REQUIRED (e.) Glue all the formers Fl through F9 onto the Lite-Ply Top Sheet. Use the alignment marks provided along the edges of the Top Sheet Pattern to aid in getting the formers properly located. Also, use a small triangle or other 90° object to make sure the formers are perpendicular. Let dry. (1.) BASIC FLOAT ASSEMBLY The following instruction sequence describes building one float at a time. When finished through step (lp.) on page 7, repeat the sequence to build a second float. (a.) Since the float has a perfectly flat top, the best way to assemble it is upside down on the building board. Cut the "LITE-PLY TOP SHEET PATTERN SHOWING FORMER LOCATIONS" loose from the full-size plan and pin it down flat on the building board. Cover it with wax paper or plastic wrap for protection. (b.) Pin the 1/8" x 3" x 44-112" Lite-Ply Top Sheet in place on the pattern. NOTICE: Look at both sides of your Lite-Ply Top Sheet before pinning it down. One side will be perfectly good while the other side may have a few small knots or other imperfections. The knots are harmless strengthwise, but for appearance sake make sure the best side of the Top Sheet will be on the outside of the finished float. HELPFUL HINT: You will find that it's a lot easier to push pins through the plywood parts with a pliers than with your fingers! (f.) Refer to the "Key To Plywood Parts" on page 3 and find the diecut plywood sheet containing the Front and Rear Plywood Doublers. Mark each doubler according to the diagram. Be sure to notice in the diagram the proper locations of the four little holes that are already prepunched into each doubler. These holes mark the locations for the Nylon Mounting Brackets that will be added later. Identify the holes now to insure that you know which way the doublers should be put in the floats. When you are positive of their correct location, glue the doublers in place. (c.) Glue and pin the Special Shaped Balsa Top Corner Stringers in place along both edges of the Lite-Ply Top Sheet. Align each stringer very carefully so that it is right on the edge of the plywood. rn~ SPECIAL SHAPED BALSA STBINCEBS FRONT VIEW \..'--- LITE-PLY TOP SHEET ~:,:,." ALIGN EDGES (d.) Refer to the "Key To Plywood Parts" on page 3 and identify all of the die-cut lite-ply formers F1 through F9. Mark each former with the correct number and then remove them all from the sheets. Glue formers F5A and F5B together, aligning the edges carefully. LlTE-' f5B TOPS'"" -.\ \ F7 -'" 5 (g.) Drill through all the pre-punched holes in the Front and Rear Plywood Doublers with a 9/64" or No. 28 drill bit. Drill completely through the doubler and the lite-ply top sheet. (i.) Cut to length the 1/4" sq. Balsa Center Keeland the 1/4" sq. Balsa Front Corner Stringers that go in the notches of formers F1 through F5A. Glue and pin these pieces securely into the notches. It works best to start at former F5A and work forward one former at-a time, bending the sticks down to fit in the notches. Use plenty of pins to hold the sticks tightly in place until dry. Install 4-40 blind nuts in the holes. Tap the blind nuts in with a hammer until the prongs are completely imbedded into the wood. Spread epoxy glue over the blind nuts to keep them firmly in place. Be careful not to get any glue in the threads of the blind nuts. (j.) When completely dry, unpin the float from the building board. Carefully block sand both sides of the framework until the lite-ply top sheet and the balsa corner stringers are flush with the formers. For best results, use a fresh sheet of 80 grit garnet sandpaper on a sanding block. Don't press too hard against the balsa stringers while sanding or they may give. Use long, light strokes along the length of the float. (h.) Cut the 1/4" sq. Balsa Center Keel and the Special Shaped Balsa Rear Corner Stringers to fit in the notches of formers F5B through F9. Glue and pin in place. Note: Both of the Rear Corner Stringers can be cut from one piece of 48" long special shaped balsa stock. (k.) Glue one sheet of 3/32" x 5" x 48" Balsa Side Sheeting on each side of the framework. When dry, trim the edges of the balsa sheets flush with the framework. 6 (I.) Carefully block sand the bottom of the framework to get the center keel, corner stringers, and side sheeting all flush with the bottoms of the formers. Be careful at the front of the float to bevel the 1/4" sq. balsa center keel equally on both its right and left sides. There should be a slight peak down the center of the keel when done. (n.) The Lite-Ply Bottom Front Sheeting is provided die-cut. Refer to the "Key To Plywood Parts" on page 3 and mark the pieces in the diecut sheets according to the diagrams on that page. Be sure to write on each piece which edge is the center seam. Then remove the pieces from the die-cut sheet and trial fit them on the float without glue. You may have to touch up the center seam edge of each piece slightly with a sanding block to get a good tight fitting joint. When satisfied with the fit, glue the Bottom Front Sheeting pieces in place. Use plenty of pins to hold the pieces securely in place until dry. (m.) A piece of 1/8" x 6" x 24" Lite-Ply is furnished for the Bottom Rear Sheeting that goes from former F5B to former F9. It's best to trim the lite-ply to a fairly close fit before gluing it on the float. First trace the outline of the float on the lite-ply, cut it out about 1/16" or so oversize, and then glue it in place. When dry, trim and sand the excess off flush with the balsa side sheeting. Avoid cutting or sanding into the balsa sides. When dry, trim and sand the excess lite-ply off flush with the sides of the floats. Avoid cutting or sanding into the balsa sides. (0.) Glue the 1-112" x 2" x 4-112" Balsa Nose Block onto the front of the float. When dry, carve and sand to a pleasing shape thatflows into the basic contours of the rest of the float. 7 Sand the side-view of the Nose Block to the shape shown on the sideview of the full-size plan. Sand the top-view of the Nose Block to a semicircular shape as shown here. If carving isn't one of your strong suits, try this simple procedure. First use a razor saw to lopp off the biggest unwanted corners of the Nose Block. The Nose Block is now basically done. Finish it up with a little fine sandpaper to smooth out any rough spots and round the corners slightly. Sand the Nose Block even with the float sides, top, and bottom. Make the Nose Block a continuation of the float shape. (p.) Finish sanding the entire float smooth with 220 grit sandpaper to prepare it for finishing. Round the corners as shown in the cross-section drawings. NOW GO BACK TO STEP (la.) ON PAGE 4, AND REPEAT THE PROCESS UP TO THIS POINT TO BUILD ANOTHER IDENTICAL FLOAT. 8 (2.) MAKING THE SPREADER BARS (a.) Two pieces of 1/4" x 1-1/8" x 19" plywood are provided for making the Spreader Bars which link the floats together. Draw the lines shown in the photo below on each end of both Spreader Bars. Measure carefully and draw the lines with a sharp pencil. (e.) Bolt the Spreader Bars, along with the Nylon Mounting Brackets, in place on one of the floats. Use the 4-40 x 3/4" Mounting Bolts provided. As you're tightening down the bolts, use a 90· triangle as shown below to insure that each Spreader Bar is square to the float when viewed from above. Line one side of the triangle up with the edge of the float's lite-ply top sheet and the other side to the spreader bar. (b.) Hold (or tack glue with "super glue") one of the Nylon Mounting Brackets in position between the drawn lines and carefully mark the four mounting hole locations. (f.) Now bolt the other float to the other ends of the Spreader Bars. Use the 90· triangle again to insure that the float is bolted on square. (c.) Drill the mounting holes through the Spreader Bars with a 1/8" or No. 31 drill bit. (3.) WATER RUDDER CONSTRUCTION (a.) A 1-1/2" long piece of triangular shaped basswood is provided for making the Rudder Mount. Use a sanding block to round off the 90· corner of the mount as shown here. BASSWOOD RUDDER MOUNT / A "'"~ROUND CORNER FULL-SIZE PATTERN ~ (b.) Use the 1/8" o.d. x 1-1/2" long brass tube supplied as a bearing for the hole in the rudder mount. Push the brass tube carefully into the hole until it is flush with the wood on both sides. (d.) Sand the Spreader Bars to final shape. Simply round the edges and smooth out any rough spots. SAND TYPICAL CROSS-SECTION OF SPREADER BARS " R BASSWOOD RUDDER MOUNT ~ CORNERS ~-~-~~-j/~-j0--ROUND BBASS TUBE BEABINC~ 9 (c.) Glue the basswood rudder mount onto the rear end of the LEFT float. Make sure it is centered and straight. Let dry. (g.) Assemble all the water rudder parts as shown and check to see that it turns freely. (d.) Sand the basswood rudder mount, with brass tube installed, flush with the top and bottom surfaces of the float. (4.) MOUNTING THE FLOATS TO A SIG 1I4-SCALE PIPER J-3 CUB OR CLIPPED WING CUB The finished floats can be mounted on a Sig 1/4-scale Cub using the brace wires and mounting hardware supplied in this kit. Nothing additional should be needed. The float's front brace wire mounts in the same L.G. Block that normally holds the front wire of the Cub's standard wheel landing gear. The L.G. Block in the Cub that normally holds the rear wire of the wheel landing gear will not be used for the float installation. Instead, a new Rear L.G. Block must be installed further back in the fuselage to accomodate the float's rear brace wire. The exact location for this new Rear L.G. Block is shown on the float plan. Getting the location correct in the model is very important! If you install the block too far off, the brace wires furnished may not fit properly. Measure carefully in these next steps! (e.) Remove the lite-ply water rudder from its die-cut sheet and sand the outer edges round. (f.) Trial fit the 3/32" diameter wire horn into the slot in the lite-ply water rudder. Alter the slot a little if necessary for a good fit. Then lay the water rudder down on a piece of wax paper or plastic wrap and glue the horn into the slot permanently. Reinforce the horn installation byapplying a small patch of lightweight fiberglass cloth(*) and epoxy glue over it, on both sides of the rudder. (a.) Measure from the CENTER OF THE GROOVE in the Front L.G. Block back exactly 6-3/8" along the bottom of the fuselage near one edge. Make a mark there with a sharp pencil or fineline felt tip pen. Repeat the measurement and make a similar mark along the opposite edge of the fuse bottom. 63/8" NOTE: These instructions assume that you are retrofitting these floats to a finished Sig Cub. If your Cub is uncovered, you can skip step (4a.) and simply make the 5-9/16" measurement called for in step (4b.) from the back corner of the Cub's standard rear I.g. block (see side-view float plan). 10 (b.) Now measure back from the two 6-3/8" marks an additional 5-9/16" along each edge. Draw a line between the two 5-9/16" marks, completely across the bottom of the fuselage. Extend the line a little ways around the corner onto the fuse side. This line is where the CENTER OF THE GROOVE in the new Rear L.G. Block will go. (c.) Using a sharp new razor blade or modeling knife, cut through the model covering on the 5-9/16" line. Also, cut through the covering for a little ways along the edge of each fuselage side so that the covering can be pulled back, exposing the model framework. Use some masking tape to hold the loose covering back out of the way for the next step. (d.) Notch the inside, balsa portion of the Cub fuselage side to receive the new Rear L.G. Block. Do not notch into the outer lite-ply portion of the fuse side. The notches should be 1" wide and 1/2" deep, same as the block. Make sure that the CENTER OF THE GROOVE in the L.G. Block will be located exactly at the 5-9/16" line. Epoxy the L.G. Block securely into the notches, flush with the bottom of the fuselage. Let dry. cyanoacrylate "super" glue. Double glue the seams to make sure they are down securely. After the glue is dry, reshrink the Koverall with a hot air gun. Lightly sand the seams with fine sandpaper and then repaint the patched area. When dry it should look as good as new! (f.) Solder 5/32" 1.0. Flat Metal Washers onto the axles of both the Front and Rear Brace Wires. Note that the washers should end up being 15-7/8" apart, as shown in the front-view on the plan. That's the same as the distance between the Nylon Mounting Brackets on the floats. SOLDERING HINT: Slip a short piece of Sig Heat-Proof Silicone Fuel Tubing(*) onto the axle of the brace wire, and push the tubing right up against the washer to hold it in correct location for soldering. The tubing will also keep excess solder from getting on the wrong side of the washer. After the solder cools, cut the fuel tubing off of the wire. (g.) Insert the Front and Rear Brace Wires into their Mounting Brackets. You'll have to take the Mounting side loose from the float long enough to slip the wires 5/32" 1.0. Wheel Collars supplied to lock the wires in (e.) Glue the loose covering material back down to the model framework and to the new L.G. Block. Pull the covering as tightly as possible back into its original position. Choice of glue for this will depend upon what type of covering material is on your model. Our Cub in the photos is covered with heat-shrinkable Sig Koverall fabric, painted with dope. The Koverall can be glued back down with either Sig-Ment glue or respective Nylon Brackets on one in place. Use the the brackets. (h.) Next install the Diagonal Brace Wires. This assembly is critical because the Diagonal Brace Wires link the Front and Rear Brace Wires rigidly together and establish the final geometry of the floats in relation to the model. Ideally, we want the flat tops of the floats to end up parallel to the 0° datum line of the Cub's fuselage. This is the procedure for in- Ii ystalling the Diagonal Brace Wires that we have used with good results: First you need to secure the Rear Brace Wire perpendicular to the top of the floats. Use a 90° triangle and a piece of 1/4" thick scrap plywood to align the wire. Draw two lines, 5/32" apart, exactly in the middle of the Spreader Bar to locate the 90° corner of the triangle. Tack glue the triangle and plywood in place to hold the wire solid. Next link the Front Brace Wire to the stationary Rear Brace Wire by tack gluing a couple scrap balsa sticks between them. The tops of the Brace) Wires should be exactly 11-7/8" apart. Measure from the center of one wire to the center of the other. 11 Solder the bindings with a heavy-duty soldering iron, rosin core solder, and plenty of soldering paste. The secret of soldering a good strong joint is to get the wires and binding hot enough to melt the solder by themselves. Don't melt the solder with the iron and then try to get it to stick to the cool binding. Solder won't flow into the binding and stick to the wires if they aren't hot enough. First hold the soldering iron on the binding and let the heat build up in the wires. Touch the solder to the binding occasionally'until it starts to melt. Add soldering paste and keep melting solder into the joint until the binding is completely full. Reheat the joint as needed to keep it up to temperature while soldering. Be careful when soldering the lower bindings not to melt the Nylon Mounting Bracket (you can take the bracket off while soldering if you make sure the wires don't shift). Cover the floats during soldering with a cloth so that dripping solder and paste will not fall on the bare wood. After all the joints are cool, clean them with a little dope thinner or other solvent on a rag. Break away the tack glued 90° triangle and the balsa and plywood jig supports. (L) Set the completed floats in place on the fuselage. The Brace Wires are to be held in the grooved blocks in the fuselage with four Molded Nylon Landing Gear Straps. Notice in the photo below that the Landing Gear Straps should be installed as near to the edge of the fuselage as possible, right up against the Brace Wire where it starts to come out of the groove. This is done to insure that the floats cannot shift sideways in the groove once all four straps are screwed in place. The Front and Rear Brace Wires are now rigidly linked together in correct alignment. Bind the Diagonal Brace Wires in place using the soft copper wire provided. Use approximately 2 ft. of wire for each binding. (j.) To install the Nylon Landing Gear Straps, first make sure that the floats are properly centered in the grooves. Hold the Straps in place and mark the hole locations on the grooved blocks. Then use a 1/16" drill bit to drill pilot holes in the blocks for the screws. Next screw the Straps in place using the #4 x 1/2" Sheet Metal Screws provided. 12 SIDE- VIEW ALIGNMENT SIG 1/4-SCALE CUB 0° 0° When top of floats are level, model should also be level or slightly nose up. 0° 0° ••• BALANCE POINT (k.) Double check the final alignment of the floats to the Cub fuselage. Set the Cub, with floats mounted, on a smooth flat surface and slide scrap wood blocks or books underneath the front and rear ends of the floats to keep the model from tipping fore or aft. Now set a small carpenter's bubble level on top of one float and shift the blocks in or out until the level indicates that the float top is perfectly level. Now step back 10 to 20 feet and eyeball the alignment of the Cub fuselage. Does it appear to be level with the floats, slightly nose up, or nose down? If you've assembled the pre-formed brace wires accurately, it should sit very close to level. If you can't tell for sure by eyeball, move the bubble level to the bottom edge of the Cub's side windows and/or on top of the stabilizer. Both of these places are 00_00with the Sig Cub's fuselage 00 line. Slight adjustments to the final alignment can be made by cutting small shims from 1/64", 1/32", 1/16", or even 1/8" thick scrap plywood(*) to fit between the Nylon Mounting Brackets and the Spreader Bars. If you want to raise the nose slightly, put shims under the front mounting brackets of both floats. To lower the nose, put the shims under the rear mounting brackets. Use the shims as necessary to get the Cub fuselage level with the top of the floats. being off a 1/4" or so won't make any difference at all in performance. Notice on the float plan that the Cub ended up with the step slightly behind the model's normal balance point, and this location has performed very well. In fact, we've shifted the Cub's balance point around a little with the installation of different engines, hot plug battery, etc., and none of the changes altered the model's float performance to any degree. Aim for getting the step as close as possible to your model's projected balance point. Secondly, the floats must be accurately aligned with the model in the top, front, and side-views. From the top and front views, they should be perfectly straight and square in relation to the airplane. Looking from the side-view, when the tops of the floats are level, the airplane should also sit level or with its nose slightly up. In the Cub installation, the floats and fuselage datum line are exactly parallel (00_00) to each other. With the Cub's large flat-bottomed wing and positive wing incidence relative to the fuse, this alignment performs well, lifting off the water effortlessly once flying speed is reached. If you're planning to put the floats on a model having a fully symmetrical wing and 00-00 wing alignment, you may want to have the entire airplane sit slightly nose up on the floats. If necessary small changes can be made to the final alignment after test flying by using thin plywood shims under the nylon mounting brackets, as described for the Cub installation. Plan out your installation by first drawing or taping a side-view of your model's fuselage on the float plan. Don't forget to consider both the step location and the incidence angle of the floats in relation to the fuse, as just discussed. Next decide where you want to locate the grooved L.G. Blocks in relation to the model's structure. You may be able to locate the blocks so that the pre-formed Front and Rear Brace Wire supplied for the Sig Cub can be used in your installation. If that doesn't prove possible and new brace wires will have to be bent, locate the grooved blocks wherever it is most practical. Keep in mind that the location of the spreader bars and nylon mounting brackets on top of the floats should be left unchanged. Also try to keep the front and rear grooved blocks about 12 to 15 inches apart in the model, to achieve best geometric strength in the layout of the brace wires. Once you've decided on the best locations for the grooved I.g. blocks, install them permanently in the model. (5.) MOUNTING THE FLOATS ON OTHER MODELS The Cub/float installation just shown can provide useful guidance for mounting these floats on other models. The Cub mounting hardware should also be useable in most cases. When planning your installation, just remember two important points concerning the final alignment of the floats to the model; First, the "step" of the floats should be located right under, or just slightly behind the model's balance point. The exact step location is not super critical, just as long as you're fairly close. On models of this size, Bending a set of new brace wires to fit your particular model is basically a matter of trial and error. Set the assembled floats on a large flat surface and use scrap wood blocks or books underneath the front and rear ends to hold the floats in perfectly level position. Put a small carpenter's bubble level on top of one float, and then shift the blocks in or out until the bubble level indicates that the floats are perfectly level. Next use more wood blocks, books, paint cans, or whatever to jig up your airplane in proper position over the floats. It may take a little time to get the model securely blocked up in correct alignment, but make sure you get it right. Then take a wire coat hangar, or other soft bendable wire, and trial bend it to fit as one of the brace wires. Unbend and rebend the coat 13 hangar until you get the shape just right to fit in the grooved I.g. block and the nylon mounting brackets. Once you're satisfied with the fit, draw the shape of the coat hangar on paper and bend your actual new brace wire out of 5/32" music wire to match the drawing. Repeat the process to develop patterns for the other brace wires. When they are all done, bind and solder the new wires in permanent position. Be sure to read the instructions in this book about mounting the floats on a Sig Cub. You may find them helpful in making your installation. (d.) One 4 inch length of nylon tubing is provided for making the cable guides that go on the rear brace wire (see plan). Cut the 4" piece into two 2" long pieces using a razor blade or sharp modeling knife. Heat the middle of one of the pieces with a hot air gun or hair dryer until it softens enough to be bent 90° without buckling. Hold in shape until it cools. Do the same for the other piece of tubing. Trim the excess length off both ends of the guides so they match the ones on the plan. (6.) COVERING AND PAINTING THE WOOD PARTS The two floats, the two spreader bars, and the water rudder must be covered and painted to make them waterproof. Completely disassemble these parts from the brace wires and from each other so they can be finished separately. We have tried two different finishing methods on our prototype floats. Both provide a durable, flexible, long-lasting, waterproof finish. METHOD I: Cover your floats with light-weight fiberglass cloth (3/4 oz. per sq. ft.), adhered with either slow drying epoxy glue or thin cyanoacrylate adhesive. Then paint the covered floats with epoxy primer and epoxy color paint (like K&B or Hobbypoxy). If you use slow drying epoxy glue to adhere the glass cloth, apply it sparingly to avoid adding too much weight. Use a plastic epoxy spreader (Sig SH-678) or an ordinary playing card to scrape off all the excess epoxy once the cloth is saturated. Remember, the strength will come from the fiberglass cloth, not from the glue. Extra glue adds weight, not strength. METHOD II: Cover your floats with Sig Koverall polyester fabric adhered with Sig Nitrate Dope or Sig Stix-It adhesive. Then paint the covered floats with Sig Supercoat clear and color dope. Both of these methods are commonly used by many modelers for covering and painting their entire airplanes. We assume since this float kit is an accessory for a completed model, that you may already be familiar with one or both of these finishing methods. Which finishing method to , use is really a matter of personal preference. The finished weight of the floats comes out about the same either way. If you haven't ever painted a model before, we suggest that you consult your local hObby dealer or local model fliers for their recommendations. The brace wires and nylon mounting brackets can also be painted with epoxy paint if desired for appearance sake. They don't need it for waterproofing. Enamel paint of any kind is not recommended for the floats. Most all enamels get brittle with age and could develop hairline cracks that would let water seep in. Iron-on plastic or cloth coverings are not recommended. No matter how well they are put on, inevitably a seam in the covering will loosen enough to let water seep in. (7.) FINAL ASSEMBLY AND WATER RUDDER HOOKUP (a.) Once the wooden parts are completely covered and painted, reassemble the floats for the final time. Squirt a little silicone rubber sealer(*) in the bolt holes when screwing down the nylon mounting brackets for waterproofing. (b.) Mount the floats back on the model. If the Front and Rear Brace Wires fit a little loose in the grooves on the landing gear blocks, squirt a bead of silicone seal(*) in the grooves just before putting the wires in. Wipe off any excess silicone, and then let dry before flying. Also, on a Sig 1/4-scale Cub, it's a good idea to cover the open bolt holes left in the bottom of the fuselage from the wheel landing gear installation with small pieces of plastic tape so water can't get inside. (c.) To hookup the water rudder steering cables, your model must have a control horn on each side of its rudder. The Sig 1/4-scale Cubs already have this. If your model doesn't have dual rudder horns, you'll have to install them or come up with an alternate method of actuating the water rudder. The horns should be as low as possible on the rudder for easiest cable hookup. (e.) Bind the nylon tubing cable guides onto the left leg of the rear brace wire with regular household sewing thread(*). Locate the bottom guide as low as possible on the leg. Locate the top guide about 4 inches up the leg above the bottom guide. You can't put the top guide all the way to the top for most airplanes because the steering cables must be able to exit the guide and connect to the rudder horns without rubbing on the fuselage. Coat the thread bindings with epoxy glue to make them waterproof. Let dry. (f.) A 1/16" o.d. x 1-1/2" aluminum tube is provided for making crimpers to secure the ends of the steering cables. Cut the aluminum tube into 4 pieces 3/8" long each. A single-edge razor blade works real well for this. Just hold the blade against the tube with medium pressure. Roll the blade and tube forward and backward a few times while pushing down. If the blade is sharp it should cut through the soft aluminum tube clean and easy without collapsing it. 14 (g.) A 12 foot length of braided steel wire is provided for making the steering cables. Cut it into two 6 foot long pieces. Slide one of the aluminum tube cable crimpers over the end of one of the cables. Next loop the same cable end through the water rudder steering arm and then back through the cable crimper. Cinch up the loop in the cable to make it smaller, but not so tight that it binds on the arm. Smash the cable crimper flat with a pliers. Repeat the process to fasten the other steering cable to the other side of the steering arm. (h.) Pass the loose ends of both steering cables together through the cable guides on the rear brace wire and then back towards the dual rudder horns. Determine which cable goes on the right side of the rudder and which goes on the left for proper steering direction. Lock the model's air rudder and the float's water rudder in neutral position. Then crimp the ends of the steering cables to the rudder horns in the same manner you did the water rudder ends. Be sure to pull the cables tight, taking out all the slack, before smashing the aluminum cable crimpers. NOTE: If you want the steering cables to be removable, we suggest that you incorporate #7 size fishing swivels(*) into the ends of the cables where they hook to the air rudder .. COMPLETE KIT PARTS LIST BALSA 4 - 3/32" x 5" x 48" Side Sheeting 2 - 1-112" x 2" x 4-114" Nose Blocks 4 - 114" x 114" x 48" Sticks for Center Keel and Front Corner Stringers 6 - Special Shaped x 48" Sticks for Top Stringers and Rear Corner Stringers DIE-CUT PLYWOOD - See "Key to Die-Cut Plywood Parts" on Page 3 SAWN PLYWOOD 2 - 118" x 3" x 44-112" Lite-Ply Top Sheet 2 - 118" x 6" x 24" Lite-Ply Bottom Rear Sheeting 2 - 114" x 1-118" x 19" Spreader Bars HARDWOOD 2 - 112" x 1" x 6" Grooved L.G. Blocks 1 - 1" Triangular x 1-112" Basswood Rudder Mount , MUSIC WIRE 1 - 5/32" Dia. 1 - 5/32" Dia. 2 - 5/32" Dia. 1 - 3/32" Dia. Formed Formed Formed Formed Front Brace Wire Rear Brace Wire Diagonal Brace Wires Rudder Horn HARDWARE 4 - Molded Nylon Mounting Brackets 16 - 4-40 x 3/4" Mounting Bolts, for above brackets 16 - 4-40 Blind Nuts, for above bolts 4 - 5/32" I.D. Wheel Collars 4 - Socket Head Set Screws, for above collars 1 - Hex Key Wrench, for above screws 4 - 5/32" I.D. Flat Metal Washers 4 - Molded Nylon Landing Gear Straps 8 - #4 x 112" Sheet Metal Screws, for above straps 1 - 118" a.D. x 1-112" Brass Tube Bearing, for water rudder 2 - Nylon Washers, for water rudder 1 - Molded Nylon Steering Arm;·Jor water rudder 1 - 3/32" I.D. Wheel Collar, for above steering arm 1 - 4-40 x 3116" Round Head Set Screw, for above collar 1 - 1116" a.D. x 1-112" Aluminum Tube, for cable end crimpers 1 - .012" x 12 Ft. Roll Braided Steel Cable, for steering cables 1 - 4" Long Nylon Tube, for cable guides 1 - 10 Ft. Roll Copper Wire, for binding brace wires MISCELLANEOUS 1 - Full-Size Plan 1 - 16 Page Instruction Book 15 (8.) PRE-FLIGHT With the floats installed, ready to fly, recheck the balance point of your model. As mentioned in the introduction, the addition of the floats shouldn't change the balance of the model very much. It's just a good ,idea to double check before attempting to fly. Don't hesitate to shift your ,.1"lceiver battery or add nose weight if necessary to keep the balance point where it belongs. Don't try to fly an out-of-balance airplane! fast enough for the air rudder to become effective, you can steer a little better. You'll also find that most float planes will turn much better to the left than they do to the right due to engine torque. Sometimes, if you're having trouble turning the model to the right to point it in the direction you want to go, try making a wide left turn all the way around the other way. Waterproof your model and radio as much as possible. You'll find that it is almost impossible to keep all moisture out of your airplane. Water has a tendency to get inside the smallest openings. However, if you take a few simple precautions you can usually avoid any serious problems. First, seCiIany openings in the model as you can, especially on the bottom half of the fuselage where there will be a lot of water spray. Don't try to seal the pushrod exits, you shouldn't put any bind on them and they are most likely high enough above the water to avoid being a problem. Put your receiver and battery pack in plastic bags and seal the bags shut with rubber bands. These two important pieces of equipment often sit on the bottom of the fuselage where any water that does get in will naturally collect. Mount all radio or battery switches inside the fuselage and actuate them with push/pull wires to the outside. Keep the charging jack inside the fuselage also. Do not mount your servos against the floor of the model. Following these few guidelines should provide adequate waterproofing in most cases. In spite of all precautions, a wet interior is inevitable at some time. Make interior checks between flights and at the first sign of any moisture, dry everything out completely before flying again! If your servos or receiver get wet, open up the cases, blow them out, and allow to dry thoroughly before reassembly. (9.) FLYING Float flying is fun! It's no more difficult 'than flying off land, just a little different. If you can successfully fly a model with wheels, you can be just as successful flying off the water. Some aspects of float flying are a little .9asier. For instance, most water flying sites are much bigger and flatter than any model runway. On the other hand, if your engine stops at any time while you plane is away from shore, it's a lot harder to retrieve the model, unless you have a boat. For that reason, your engine's idle reliability is very important! For added security, we recommend that you install a permanent onboard glow battery(*) in your floatplane to keep the glow plug lit at idle. Battery systems for this purpose are available from Ace R/C and other companies. The best time to fly off water is when the wind is below 10 mph. In higher winds, taxiing into position for takeoff and back to shore after the flight, can become very difficult. Simply stated, the "grip" of the floats on the water is nothing like the grip of wheels to land. Your model will want to slide or drift across the water with the wind. It will also tend to weathervane into the wind. The floats just won't hold the model from turning as wheels would do on the ground. Likewise, the water rudder is too small to hold all of the rest of the model which is above water from turning when the wind is too high. Sometimes, if you can get your model going We aren't trying to make it sound like float flying is difficult. Just trying to explain some of the main differences from land flying. Except while taxiing, the wind is no more of a factor in float flying than it is in land flying. Experience will quickly teach you how much wind is too much. Below 5-10 mph, the water rudder is effective and you can steer the model at slow speeds quite effectively. Until you gain some experience, wait for a relatively calm day tryout your new float plane: For maximum enjoyment, the less wibcjthe better! Always try to takeoff directly into the wind. Hold full up elevator and smoothly advance the throttle. Steer straight with the rudder. As the model accelerates, relax the up elevator and the plane will lift up and start riding on the step of the floats. The back end of the floats will be out of the water and the airplane will accelerate even faster. You should be holding very little, if any, up elevator at this point. When flying speed is reached pull up slowly on the elevator until the plane lifts off. Keep your c1imbout and turns gentle until you model will probably not fly too much different its wheel landing gear. Just a little bit heavier. goes on glassy smooth water is pure joy. Good get to safe altitude. Your on floats than it did with Doing endless touch and luck and happy landings! )" -; PRINTED IN U.S.A. ©SIG MFG. CO., INC. 1985
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