EPP Version Building Notes Updated 12-10-2013 The Zulu covers a wide range of flying conditions: slope soaring in light to strong lift, thermalling, aerobatics, discus launches, and combat; for skill levels from beginner to expert. What would you do, with a Zulu? The Zulu can be built with or without control surfaces along the leading edge, dubbed here as drooperons. The drooperons can be actuated by the same servo as the elevons, making setup fairly simple. With drooperons installed, the Zulu can reach a much, ~80%, higher lift coefficient before stalling, both right-side-up and inverted. This allows for tighter turns, loops, and a lower sink-rate. The drooperons are also effective at increasing roll-rate, especially at low speeds. With drooperons, the Zulu is also more stable during the deep-stall maneuver, making landings and altitude control easier. The disadvantages of the drooperons include higher drag from the extra control surface gap, increased build-time, and higher likelihood of breaking a servo during impact (although this is rare with metal-geared servos). Specifications: Wingspan: 48 in (1.2 meters) Wing area: 472 in 2 (30.5 sq.dm) Typical Fling Weight: 11.5 oz (325 gm) Wing Loading: 3.5 oz/sq.ft (10.7 gm/sq.dm) Wind Range: 0-25+ mph Kit building time: ~12 hours Recommended radio gear equipment: 1. 2+ channel receiver and 2 servos 2. Radio with flying wing / delta wing mixing capability, Expo/Dual-rate preferred 3. Battery and servo starting points on the following page Kit contents: 1. EPP wing cores 2. Two.02 x.118 x 48 (.5mm x 3mm) Carbon ribbons 3. One.02 x.118 x 24 (.5 mm x 3mm) Carbon ribbon
Recommended building materials: 1. Welder glue or Beacon's Foam Tac. 2. Thin, foam-safe CA glue 3. Razor blade, x-acto or box cutting knife 4. Drywall sanding sheet 5. 3 Mil Laminating film (New Stuff) or other covering material 6. G10 / FR4 fiberglass or plywood for making control horns 7..047 (1.2mm) wire for pushrods 8. Four Dubro mini E/Z connectors 9. Small lead weights for balancing 10. 10mm epp sheet for pod and 5mm epp sheet for fin Pod options: Fiberglass pod available near the end of December Make your own epp pod. (building instructions in this document)
a. 2-Cell 7.4V Lipo + BEC http://www.hobbyking.com/hobbyking/store/ 92 76 Turnigy_800mAh_2S_20C_Lipo_Pack.html http://www.hobbyking.com/hobbyking/store/ 92 76 Turnigy_800mAh_2S_20C_Lipo_Pack.html http://www.hobbyking.com/hobbyking/store/ 92 76 Turnigy_800mAh_2S_20C_Lipo_Pack.html http://www.hobbyking.com/hobbyking/store/ 21 331 ZIPPY_Compact_850mAh_2S_25C_Lipo_ Pack.html http://www.hobbyking.co m/hobbyking/store/ 17 158 6V_3A_UBEC_2_ 5S_Lipoly_6_23v_.html b. 2-Cell 6.6 V Lipo http://www.hobbyking.com/hobbyking/store/ 14075 ZIPPY_Flightmax_700 mah_6_6v_5c_lifepo4_reciever_pack.html c. NiMh http://www.alofthobbies.com/radio-gear/batteries-nimh.html Servo Options: Metal gear servos recommended. Some low-cost options: http://www.hobbyking.com/hobbyking/store/ 9392 Turnigy_MG90S_Metal_ Gear_Servo_1_8kg_13_4g_0_10sec.html http://www.hobbyking.com/hobbyking/store/ 27569 Turnigy_TGY_50090M _Metal_Gear_9g_Analog_Servo.html http://www.hobbyking.com/hobbyking/store/ 25454 Turnigy_XGD_10HM_ Digital_Micro_Servo_2_2kg_10g_0_12.html http://www.hobbypartz.com/33p-solarservo-a107.html http://www.hobbypartz.com/33p-solarservo-d654.html
Steps: 1) If there are any epp strings on the foam core, remove them. A spare chunk of epp can be used as a sanding tool. 2) Mark the control surfaces, spar locations and wing-tip rounding with a fine-tip marker or pen. (dimensions on following page) 3) Cut and sand the rounded wing tip. 3M Drywall sanding sheet can be used for rounding the wing-tip:
Wing Bottom 124mm 100mm depends on pod width 45mm 220mm 150mm 82mm 32mm 80-115mm 140mm 90mm
4) Cut out and bevel the control surfaces. 35 35. Optional: Glue hinge the control surfaces with Welders glue. If you skip this step, the control surfaces can be joined with the covering material. Welders Glue hinge videos 5) Glue the two halves together. Welder glue works well for this. 6) Install the carbon flat pieces to form the spar pin carbon ribbon 35 35 carbon ribbon The carbon strips are used on both the top and bottom surfaces. By marking the cut location with pins that go all the way through the foam, you can make the slits are directly in line with each other. Mark the cut location with a fine pen then cut, or cut along a straightedge as shown to the right. The cut should be just slightly deeper than then width of the carbon ribbon, 3mm.
7) Push the carbon pieces into the slits using the rounded end of a screw driver handle. Applying a little bit of pressure will sink the carbon to just below the surface of the foam. After all the carbon is installed; but before gluing; make sure the wing is straight and flat. It is easy to tweak it at this point to get the wing perfect. Once you are happy that the wing is straight, wick thin CA into the slits. This will lock the carbon in place and will also "heal" the slit you cut in the foam. Do the top first, make sure the CA has cured and then flip the wing over and do the bottom. 8) Sand the entire wing with 3M Drywall sanding sheet. This will make a nicer final finish and improve the bonding. 9) Cover the wing. 3 mil New Stuff laminating film works well. It can be purchased by the foot here: http://www.alofthobbies.com/new-stuff-laminating-films.html This is a good video on covering with laminating film. Fast-forward to around 3:28: http://www.rcgroups.com/forums/showpost.php?p=26572343&postcount=23 a. Iron the laminating film around the drooperons: b. Do the same for the elevons, but seal the ends together, past the trailing edge. Trim off the excess covering material with scissors. Leave about 3mm past the trailing edge. This adds a considerable amount of stiffness with 3mil laminating film. ~3mm c. Cover the rest of the wing d. Make hinges with the covering material. e. Now fold up the control surfaces up and add a second layer to finish the hinge.
10. Install the control horns and radio gear Make control surfaces out of 1/32 (0.8 1.0mm) G10 / FR4 fiberglass or plywood. Check that the drawing below prints to scale if you are using this as a template. G10 / FR4 can be found here: http://www.mcmaster.com/#8667k51/=ppobas http://www.alofthobbies.com/g10-fiberglass-plate-2mm-x-350mm-x-150mm-078-x-13-77-x-5-9.html Z - bend Dubro Mini E/Z Connector The control horns were designed to approximate the most efficient combination of elevon and drooperon deflections. However, the ideal relationship depends on CG location and flying style. The charts on the following page can be used as a guide to change the mechanical advantage if needed.
a. Mark the control horn locations and cut slits for them. b. Place the servos near the inboard edge of the elevon and cut out the servo wells. You can cut all the way through, and then replace the foam on the top surface, or use the scratch and peck method to create the servo wells from the bottom side. The wing is thick enough that you don't have to go all the way through. A guide for this method can be seen here: https://www.youtube.com/watch?v=_wf0jb2ek2m c. Use Welder or epoxy to hold the servos in place. d. Cut a slit for the servo lead and press the wires into the foam. Tape over to cover the slit.
11) Fin. Actual size template on the following page. This fin can be made from dollar tree foam or 5-10mm thick epp. Use a carbon ribbon for added stiffness, especially if you plan on doing any discus launches. Covere your fin with laminating film or packaging tape. Several ways of attaching the fin to the wing are shown. The first epp pod option includes a fin holder. Then second epp pod and the fiberglass pod do not, but the fin can be attached fairly easily as shown on the following two pages.
Fin Template, To Scale. Continued on following page 167mm 3mm x.5mm carbon ribbon Continued on next page
previous page glue 1.2mm (1/32 ) thick G10 /FR4 fiberglass tape fin back together after installing tape to wing here Finished
EPP Pod construction, Option 1 1) Glue side fuse pieces to bottom fuse piece (Welders or hot glue). Align the front of the pieces. The side pieces butt up to the bottom piece. 2) After the glue has set, trim the front end of the bottom piece so that it is flush with the side pieces. 3) Add front bulkhead, trim flush with top of side fuse pieces. 4) Glue on top fuse piece 5) Sand shape into fuse using a drywall screen 6) Glue pod to wing, recommended to strip some film from the wing and glue "epp to epp". Make sure the width of the gap in the pod is the same as the fin to be installed. You can use a small piece of fin material as a temporary gap fixture. 7) Tape the pod with 3M extreme tape. A covering iron will help get the tape on nicely and smooth away wrinkles. 8) Cut hatch to allow access to Rx and to install battery 9) Add small strip of foam to help secure installed battery in place. Be sure to bevel cut the hatch so that it cannot fall through the hatch opening. 10) Us a small piece of 3M extreme tape to make the hatch closer. Fold on end of the tape over about 1/4" to form a tab for easy opening of the tape/hatch. 11) A nylon bolt can be used to fasten the fin in place. This makes the (potentially weak) fin easy to replace at the slope.
EPP Pod, Option 1 7.0 1 1/8 2 ¼
To scale, front half of epp pod Top Side Bottom wing
To scale, aft half of epp pod Side Bottom wing
EPP Pod, Option 2. This pod is shorter, and does not have a fin holder to scale: Receiver Top Side Bottom