Fairey Swordfish Construction Notes

Designed by: Robert J Caso

Overview Wingspan 37” Wing Chord: 6.5” Wing Area: 360 sq in Aspect ratio: 5.7 Airfoil: Clark Y Length: 28” Category: Stand-off scale Scale: 1/15 Flying weight: 24 oz Engine: HiMaxx outrunner brushless 2812-1080 Prop: APC 9x4.5 slow flyer propeller ESC: Castle Creations 18 amp ESC Battery: FMA 3s 11.1v 1000 mAh Wing loading: 9.6-oz/sq ft Channels: 5; Aileron, Elevator, , Throttle, drop

History: The Swordfish is probably one of the famous aircraft of WWII. Although nearly obsolete when WWII began, it generated an impressive combat record and was employed by the and in nearly every theater of WWII. While it served with distinction in everyday roles of coastal patrol and anti- submarine duties, it is most famous for its attack and destruction of Italian capital ships at in 1940 and for its disablement of Germany’s Bismark in 1941 with a well-placed torpedo. In each of these actions Swordfish squadrons suffered few losses. It was reported that the Bismark’s anti-aircraft batteries could not slow their rate of traverse enough to take down the Ark Royal’s slow moving Swordfish!

The Swordfish was employed in many variants, including float and unarmed trainer versions and was armed with a multiplicity of weapons including a torpedo, bombs, and depth charges, as well as offensive and defensive machine guns, thus making it a modeler’s dream. A few Swordfish survive today, mostly in England, and some of the survivors are flown today at popular air shows.

The Model: The model was designed using 3-views contained in Warpaint Series # 12 by Hall Park Books Ltd (ISSN # 1361-0369). This publication details a more complete history of the Swordfish and contains many detail photos of Swordfish variants along with many colorful drawings showing the various paint schemes employed during the Swordfish’s operational history. Tamiya plastic model company offers a very nice 1/48 scale plastic model of the Swordfish, including a float version. The prototype was painted with latex paint mixed to the appropriate colors to represent an aircraft that flew from the Ark Royal during the ’s encounter with the Bismark.

The kit employs interlocking precision laser cut components to ensure speed and accuracy of construction as well as a rigid but light airframe. The framed, sheeted and uncovered airframe weighs less than 8 ounces. Medium CA is to be used throughout construction. All parts are engraved with their respective part numbers called out in the plans and in these instructions. The kit is somewhat intricate and contains many parts that are not easily recognizable, some of which requiring special orientation to adhere to the building design. Carefully study the plans and the construction notes prior to starting the build.

Purists will note certain deviations from scale, which were incorporated to make the model simpler to build. These are as follows: simplified cabane strut arrangement, elimination of the center wing section curvature, simplified cockpit, elimination of bracing wires and “V” wing struts, elimination of ailerons and elimination of the secondary struts.

Wing: The wing is to be built flat on a building board; use a piece of standard ½” wallboard on a flat table covered with wax paper as the construction surface to facilitate pinning the structure to the board.

The wings are made up of five panels: an upper center section, two upper outer panels and two lower panels. The leading edges, trailing edges and spars are designed to interlock with the ribs. Note that the outer upper wing panels have a sweep and a slight amount of dihedral, so take care in locating the root ribs. The dihedral rib (4C) is located on each outer panel of the upper wing and is positioned by an angle cut in the main spar; all other ribs should be affixed at 90 degrees to the building surface. Approximately ½” to ¾” of dihedral in each upper wing panel is fine.

The upper center section is constructed by first preparing a piece of medium 1/16” balsa sheet using the outlines noted in the plans that will serve as the bottom skin. Trailing edge parts #UCA and #UCB are laminated together and are applied to the top of the lower sheeting in the center section. The ribs are inserted in slots cut in the leading and trailing edges, as well as in the main spar. All five wing panels are similarly constructed, with the exception of the employment of 1/16” and 1/32” sheeting where noted on the plans. Pay special attention to these notes. All spars require the lamination of a strip of 1/16” x 1/8” spruce on their forward faces and flush with their lower surfaces. Each rib is appropriately relieved to accommodate the spruce strip. A strip of soft 3/16” square to provide airfoil supplements the leading edges. Use a sharp razor plane held at an angle to provide initial shape to the leading edges and finish by block sanding with 100 grit paper. The undersides of the leading edges should also be relieved. Trailing edges should also be feathered in to match the contour of the ribs.

The upper and lower outer wing panels employ laser cut wing tips which are attached to the leading and trailing edges when construction starts; spars and ribs are then added to the wing. Soft 1/16” balsa should be applied to the tips on the upper wing panel and sanded to provide a gentle curvature to the wing tip. Thin CA may be applied to the tops of the spars to provide additional strength to the framework. Hard 1/8” square should be used for the secondary wing spars. For a clean building job, make sure that all ribs are properly seated and come in contact with the building surface when they are installed in the wings. The inboard section of lower wing panels require the lamination of a #L1 and (2) #L2 pieces which are later sanded in to accommodate the 1/32” sheeting on their upper surfaces. Ribs #4C and the first #5 on the upper wing panels should be sanded slightly to accommodate 1/32” sheeting. The upper wing panels should be joined to the center section with epoxy noting the dihedral specifications above. A small strip of ¾ ounce fiberglass should be applied with thin CA to the underside of the joint and carefully feathered in and filled.

Each of the outer wing panels employ small 1/8” laser cut “boxes” that provide a slot to receive the wing struts. These should be backed with 1/32” balsa scrap to set the depth of each strut. The appropriate ribs (4A and 4C) in the center panel are relieved to receive struts, as are ribs #2 in the lower wing panel; each of these slots should be backed with 1/16” balsa scrap to provide a 1/8” wide cavity for the struts. Note also parts RU, FU and RL, FL serve as mounting points for the struts and also employ the small 1/8” laser cut “boxes” that are constructed as above. Special wing ribs are cut to accommodate these parts – see the plans.

The lower wing panels simply plug in to the corresponding holes and slots in the fuselage doublers using 1/8” dowels and should affixed with slow set epoxy. A very slight amount of dihedral may be incorporated in the lower wing panels to avoid the illusion of a droop in these panels.

Ailerons: Although the original model was successfully flown using only rudder, the lack of sufficient dihedral affected its handling. The wing was later upgraded to incorporate the (4) scale ailerons and corresponding changes were made to the laser cut parts. The installation of the ailerons is shown on an addendum to the plans and certain modifications must be made to the wings as a result. The primary modification is to the TE of the aileron bay which must incorporate a full depth sub-spar to pick up the upper covering on the wings. This is achieved by building the wing as per the primary plan and then adding scrap filler pieces to the aileron bay. A micro servo buried in each lower wing panel is connected to each lower aileron along with an actuating strut running from the lower to the upper ailerons so that all (4) ailerons work together. Alternatively, a single servo could be installed under the fuselage hatch, but this installation may affect access to the battery.

Fuselage: The fuselage is built upside down on a “crutch” with the bulkheads placed in their respective slots. A careful study of the plans will note that some bulkheads are comprised of two 1/16” pieces that must be laminated together to form a cross grain 1/8” part. Take careful note of how these pieces are oriented when affixing them to the fuselage frame. Some 1/16” bulkheads require the application of a scrap piece of 1/32” balsa to improve their strength – see the plans. Once the stringers and sheeting are added, the fuselage becomes a quite rigid structure but care should exercised while handling the structure before these items are added. Incidentally, the builder should fabricate his own strip stock from medium grade balsa for the 1/8” stringers and from hard balsa for the 1/16” x 3/16” stringers. This will allow the builder to precisely cut these parts to match the tolerances in the laser cut parts.

Layout the bulkheads at the appropriate stations (again noting orientation) and glue them to the pinned crutch while holding them vertical with a square. Attach the wing saddle doublers and affix soft 3/16” square stock to the corners of the lower frames from the wing doublers to the tail post. A triangular part is provided to brace the “V” formed by the intersection of the lower stringers at the tail and to provide a sufficient tail wheel mounting point. ½” medium triangular stock is to be added between bulkheads #2 and 3 and these should be sanded in to match the curvature of bulkhead #2. Add the lower 1/8” x ¼” stringer to the underside of the fuselage and the 1/8” plate forward of the wing doublers.Turn the fuselage over and add the top bulkheads and the 1/8” square stringers that span the length of the fuselage, along with the top 1/8” x ¼” stringer forward of the cockpit. It shouldn’t have taken much more than 1 hour to frame the fuselage to this point.

Tack glue bulkheads #1A and affix formers # F1 and F2 to set its position which should be perpendicular to the fuselage frame. At this point, select a good piece of contest 1/16” sheet for the fuselage sides and cut it to match the outlines shown on the plans, which replicates the skinning on the real aircraft. To keep things simple, affix sheeting first from the bottom of the fuselage to the upper 1/8” stringer and then up from the 1/8” stringer to the center stringer. Bulkhead #3A should be added when half of the upper sheeting is completed and strut slots should be cut in at this point. As on the wings, 1/16” backing should used to box in the strut slots on the bulkheads.

Drill holes for 3/32” ID aluminum tube that is to be used to support the plug in landing gear struts and test fit these but do not install yet. These should be installed with epoxy once the forward fuselage blocks have been installed and the fuselage rounded in with a razor plane and 100-grit sandpaper. Sections of soft ½” balsa are to be used to lay up the forward fuselage. When laying in the forward fuselage blocks, avoid getting CA out towards their edges – this will allow a smooth finish when sanding things in.

Once the nose is rounded, add the balance of the 1/8” square and 1/16” x 3/16” stringers to the sides and rear of the fuselage. Consider installing servos and pushrods before the stringers are added to allow access for the affixation of pushrod support tabs glued to the bulkheads. Do not omit the supporting pushrod tabs. Sheeting around the cockpit area may now be added after first roughing out the cockpit openings. Finish the openings once the sheeting is installed. An opening for equipment access is provided between the lower wing panels – this opening should be covered with a removable 1/64” plywood hatch.

The motor tube is comprised of rectangular sections of 1/16” balsa affixed to two nonagonal (9-sided) bulkheads (#1), one in 1/8” light plywood and the other in 1/8” balsa. The ply section provides a hard point for the motor mount, so this should be oriented at very front of the model. Affix this assembly to bulkhead #1A, noting the orientation engraved on #1A and taking care to ensure that the face of the mount is perpendicular to the thrust line. The mount facilitates the installation of nine dummy engine cylinders. Test fit the motor, relieving the internal bulkheads as appropriate with a drum sander mounted to a Dremel tool.

Construct the tail fillet with the help of a 1/8” sheet spacer that temporarily occupies the space taken up by the empennage. This is tack glued to the fuselage on center and then two soft blocks are glued to the turtle deck, resting on each side of the spacer. Then sand to blend in to the fuselage’s contours. Pop out the spacer out and slide in the stabilizer and rudder empennage to test fit. Use the spacer again later when covering.

Empennage: There is nothing unorthodox regarding the empennage construction. Laser cut parts are provided for the outlines and use 1/8” square hard balsa for the required strip stock. Edge sand the empennage to a smooth contour. A 1/8” square spruce strip is used to connect the elevator halves. Remove any covering from where the empennage is to be attached to the fuselage. Affix a “½ A” control horn to the elevator and attach the elevator to the stabilizer. Hinge the surfaces using flat “CA” hinges.

Equipment Installation: The motor is mounted to a round 1/16” plywood plate, which in turn is screwed to the motor tube on the model. The battery and servos should be placed initially as far forward in the fuselage as possible due to the long tail moment of the aircraft. Place foam blocks in the fuselage to prevent the battery from shifting in flight. The internal fuselage cross member at bulkhead #2 may be cut away to allow additional space for the battery. The servos are mounted inverted to the sides of the fuselage and in such a way as to allow access through the belly hatch. Balance the model with all equipment installed using the CG location shown on the plans as a reference and shift equipment accordingly. The landing gear legs are to be bent in a “V” shape with additional bends at the top so that they slide into the aluminum fuselage tubes previously installed – use epoxy to install the landing gear. A small piece of 3/32” wire is then bent in an “L” shape and wired and soldered to the landing gear to provide an axle and to provide a mounting point for the dummy strut running from the axle to the lower wing. The main landing gear legs should be faired in with 1/16” balsa. Install the tail wheel.

Covering and Finishing: Cover the airframe with a suitable iron on covering and before the flying surfaces have been attached to the fuselage. The open areas on the prototype were covered with white Litespan using Balsaloc adhesive. Follow the directions carefully when applying Litespan. To eliminate wrinkles in the Litespan, apply thinned butyrate dope to the covered airframe and lightly apply a heat gun to both dry the dope and shrink the covering. Avoid overheating. The butyrate will lock the covering’s tension in place. If the model is to be painted, do it while disassembled.

The skinned portion of the airframe was finished using 2-3 coats of thinned nitrate dope on the bare wood, sanding each with 400 backed with foam. Then I mixed some spackling compound with water and brushed that on, sanded and then more dope, this time heavily thinned. Sand again. Then I primed with Duplicolor auto body gray primer and sanded most of that off. Primed again and sanded it off again. I then applied the adhesive to the open structure and covered.

Folding Wings: The model was later designed with folding wings which necessitated now having seven separate wing panels: a central upper, two outer upper, two lower stub and two lower outer panels. Start by building the lower stub wings. The stub wing locating dowels should be run through the fuselage to connect each opposing panel and at least two bays into each panel for alignment and sturdiness during construction. The dowels will foul access to the internals of the fuselage, so they may be later cut away to provide access. Do this only after the stubs and their functional inverted “V” struts have been permanently installed, however wait until the last possible moment to permanently affix the stub wings to the fuselage to aid in running the servo wires and for fitting the outer panels. Note that for the prototype, I built, sheeted and pre-finished the stub wings and then opened the skinning to install the wing latch mechanism, replacing the cut away sheeting once this installation was complete. Just be careful with the glue. Once the latch is in and working, prepare the stubs for final finishing.

Build the center section of the upper wing, opening the holes for the cabanes and installing the 1/8x1/8” diameter magnets per the plans. Back the magnets with balsa and install balsa fill for the upper hinges. At this point the upper center section may be sheeted and finished. Note that the cabane strut layout shown is not scale.

Once the fuselage is finished and ready for paint, the cabanes may be installed on the fuselage, along with both the upper center section and lower stub wings. I recommend installing the upper center section first, jigging this into positon by using the lower stub wing dowels as the lower jigging point.

Once the outer wing panels have been built, covered, pre-finished and with the aileron servos installed and their servo leads run, these should be test fit to the inner panels for hinging and alignment. The hinges should have been already permanently installed on the inner panels at this point and their rotation checked to make sure that they rotate in parallel to each other. Additionally, at the base of each interplane strut pocket (four points on each panel, 16 in total), sections of roughened 1/16” aluminum tube that have been flattened and drilled in one end should be installed as rigging points.

The model at this point must be secured in a jig so that the proper wing alignment and dihedral can be completed and the struts and rigging installed on the outer panels. The rigging is functional and the length of the outer interplanes will establish the upper wing dihedral. Straight, sturdy balsa sticks may be banded to the underside of the upper center section to help establish the upper wing dihedral. Recommended dihedral is 3/16” for the lower panels (measured from underneath the wing at the interplanes) and 1/2” for the upper panels. These measurements are not critical – get it so it looks right and is consistent from side to side.

K&S ¼” streamlined tube is used for the both the inner and outer interplane struts and it is a test fit game to determine their length with model jigged but, since the upper wing is resting only on its dihedral spacer, it is able to move freely during this process. Once the strut lengths have been determined, modify the inners as per the plans and install these with epoxy on the outer panels and with the wings in their “in flight” configuration on the model. Prevent gluing the panels to their respective stub wings by slipping wax paper between the inner and outer panels. The outer interplanes, once their length has been determined, are easy to install and this may be done at the time the inners are installed.

Once the outer wing panels have been strutted, the next step is to rig them with .013” music wire (or close), which is easy to work. After the rigging is completed, the model may be removed from the jig and the outer wing panels may be permanently installed by gluing them to the hinges on the inners, once again posing them in their “in flight” configuration while the glue dries. Note that I finished and painted the wings on the prototype before installing the struts and rigging.

Bill of Materials: (1) Swordfish short kit (2) 36” x 1/8” x 6” balsa sheet (cowling) (1) HiMaxx outrunner brushless 2812- (1) 36” x 5/8 ” x 1” soft balsa sheet 1080 (1) 3s 11.1v 1300 mAh battery (2) ½ A control horn (1) APC 9x4.5 slow flyer propeller (1) Robart pin hinges (1) MP Jet propeller nut # 8032 (1) Pkg Dubro Micro EZ connectors (1) MP Jet propeller adapter # 8030 (2) 12” x 3/32” music wire (1) Castle Creations 18 amp ESC (1) 12” x 3/32” ID aluminum tubing (4) Hitec HS35 HD micro servos (1) Pkg Dubro #847 Micro pushrods (1) 5 channel radio (2) 2” Light wheels (2) 1/16” x 1/4” x 36” hard balsa strip (2) Rolls Litespan (72” x20”) (1) 1/16” x 3” square spruce strip (1) Small tail wheel (1) 36” x 1/8” x 1/4” balsa strip (1) Dummy torpedo kit (5) 1/8”x 24” square balsa strip (1) Dummy engine cylinders kit (1) 4” x 36" 1/16 contest sheet (4) 1/8x1/8 dia barrel magnets (1) 3”x 12" 1/32 contest sheet (1) Park Flyer Plastics 4.5” 9 cyl dummy radial (3) 36” x 3/16 square soft balsa strip (2) 1/8" x 3” dowel (1) 2” x 2” 1/16” birch plywood