The Wasp has a two piece foam wing that can be built flat with ailerons or with dihedral for 3 channel operation. It has an 8mm square CF tube for a fuselage. The tail feathers are made from a foamboard type material. It comes with a good quality red tape for covering the wing and tail surfaces. You can use the fuselage and tail pieces to build the Sea Wasp or trace and cut out the tail pieces from a piece of foamboard. Then use a 3/8” sq basswood stick instead of the CF tube. That’s what I did so I would have still have the Wasp to fly in its conventional configuration.
Hull
The Sea Wasp uses the same hull and floats that have proved to be very successful with my Slow Stick Flying Boat and Seaplane. I do sell the cut foam cores(send PM for details) but I designed the hull so it can be cut by anyone using a scroll or band saw. The cutting doesn’t need to be anywhere near perfect to work very well. The foam used 2’ x 8' x 2” thick EPS foam sheet. This is the white foam sheet insulation found in most home supply stores.
Cutting the Foam
The plans in PDF format are attached. Print out the hull plan and make a template out of poster board. The hull plan is a little longer than 2’ but I still lay them out crosswise letting a little of the tail hang over my 2” wide foam sheet. Cut out 3 of these sections using a scroll or band saw. You could also make templates and cut them with a hot wire. On one of these pieces cut out the battery and radio compartments and the slot for the rear wing saddle as shown on the other plan. Drill 3/16 holes for the float spars on the other two pieces. To taper the sides trace the bottom patterns on the bottom of the hull pieces. Make sure to flip over the pattern so you end up with a left and right side. If you have a tiltable table on your saw, tilt it 10deg and cut the side starting from the rear. Make sure you got it tilted so the top is coming out narrower. My 50yr old scroll saw doesn’t have a tiltable table so I just made a tilted platform with piece of 1/16” ply and ½” thick balsa stick. If you want to cut it with a hot wire there is also a template for the top. Save the halves that you cut off to use as cradles when you are gluing the sections together. Cut out two floats and the tail pieces the same way you cut out the hull parts. Drill 3/16” holes in the floats as shown on the plans. I like to drill these just short of going all the way though.
Before gluing the hull together you should make about a ½” hole between the battery and radio compartment. A piece of ½” copper tubing works well for this. Mark the top of the center section where you will cut for the hatch and where to cut to remove the center portion for the radio compartment. Mark the sides in this area and don’t put glue there when gluing on the sides. Note: Do not remove these prior to gluing the sides on. Glue the sides on using a thin layer of either epoxy or polyurethane glue (Probond Ultimate or Gorilla glue). Put the pieces together and then put them top side down on a flat surface. Adjust the pieces so the back of the step is aligned. Using the cutoff pieces as crutches, lay the hull on its side and add a lot of weight until the glue cures. Make sure to wipe of any excess glue. Sand the top of the hull so it is flat and sand the rear of the hull to square it up. With the top side down, glue on the first tail piece. When the glue cures, sand the sides and bottom of the tail piece to conform to the rest of the hull. Repeat this with the second tail piece. Cut out the hatch and center section. Save the piece you cut out from the hatch. Epoxy in the 1/16” ply end pieces for the wing saddle. Double check the spacing to make sure the wing fits between them. Epoxy on the ½” x ¼” balsa side pieces. On the outside of each end epoxy on a 4” x 3/16” wing hold down dowel. Epoxy in ½” x1/4” balsa wing supports inside each end. (The ¼” thickness is in the up and down direction) Glue on a 14.5” long piece of 3/8” sq basswood centered on the rear of the hull starting from the rear wing mount. You may need to notch it to get it under the dowel. If you are using the Wasp CF tube trim the stabilizer mount to remove the part that holds the servos then glue it on to the end of a 14.5” piece of the CF tube. Now epoxy the CF tube on to the hull making sure the stabilizer mount is level with the wing saddle.
Use 3/8” slices of foam to fill out the width of the hull on both sides of the basswood or CF tube. (GWS glue works well) If you use the CF tube glue a 1/16” balsa strip along the top of the tube. Do the same using ½” slices of foam along side the wing saddle. Sand the back of the step to square it up and epoxy on a 1/32” ply strip across the back of it. Take a ¾ x 1.25” x 3” piece of foam and sand it to whatever shape you like for the windshield. Glue it in place just ahead of the wing saddle. Now use a sanding block to smooth out mismatches and irregularities in the hull. Also you may want to do some shaping of the bow end. You can round the top edges of the hull but leave the bottom edges sharp. Don’t be too aggressive with the sanding as the foam is soft and it doesn’t need to be perfect like an airfoil. To repair any holes, digs or mismatches lightweight spackling works well.
Tail
Cover and hinge the elevator and horizontal stabilizer generally as shown in the instruction. The instructions have you leave the edges square and uncovered. I would round the edges and cover them. It looks better and if the paper covering on the foam gets wet it could lift. You could of course use an iron on covering instead of tape. Once the elevator is on, cut a small notch in it at the center at the hinge line. This is to provide clearance for a 1/16 wire joiner on the rudder. Epoxy on the horizontal stabilizer making sure it’s level to the wing saddle and perpendicular to the fuselage. If you are using the basswood stick add 3/8” triangle balsa stock to the bottom rear. Make sure to remove any covering where you will be gluing. Before covering the rudder, make a groove and drill a hole in the rudder so you can epoxy in the 1/16” wire joiner. This joiner will attach to a ply plate underneath for the rudder horn and a place to attach the water rudder. Cover the fin and rudder. Cut the slots for the hinges but don’t glue them in yet. Glue the fin on and add the 3/8” balsa triangles. Now hinge the rudder to the fin. To provide support for the rudder drill a 1/16” hole in a 3/8” wide piece of 1/16” ply, slip it over the wire joiner and glue it to the basswood or CF tube. The ply tab is made with a piece of 1/16” ply sandwiched between 2 pieces of 1/32”. Mount the horn on this and drill a hole for the screw that will hold on a water rudder.
Hatch Lightly sand the edges of the foam piece you cut out for the hatch so it will easily fit back into the opening. Cut a piece of 1/32” ply so it hangs over by about ¼” on all sides. Center and glue this to the foam piece. The rear is held down with a 1/8” dowel epoxied into the hatch foam with a matching hole in a piece of 1/16” ply glued onto the hull. The front is held on with a washer glued to the hatch and a magnet glued into the hull.
Pylon
The pylon is made from a piece of 1/8” ply that is 1 1/4” x 6.5”. This is longer than it needs to be but you will trim it once you are satisfied with the motor position. At one end sandwich it between pieces of ¾” x 1 3/8” ply and ¾” balsa triangle. Cut a notch in the wing support and epoxy in the pylon. The motor stick is made from 10mm wide strips of 1/8” ply. A ¾” long piece is glued between two 2.25” long pieces. To get a tight fit a 1/64” ply shim can be used. The motor stick will be bolted to the pylon at about an 8 degree angle( the motor stick about 3/16 higher at the front of the pylon than at the back..
Covering
The hull and floats should be covered at this point. You can use tape or iron on coverings. Since the surfaces are basically flat the hull and floats are very easy to cover. For more durability I decided to first cover the bottom front of the hull with 3/4oz fiberglass applied using Minwax Polycrylic. This is strictly optional. I’ve made many planes using this hull and this is the first one that I decided to try the fiberglass.
Mounting the Floats
For spars you can use 4mm CF tubes or 3/16” wooden dowels that are about 14” long. On a flat surface assemble the floats, spars and hull. Place a 5/8” high block under the back of the floats. It is likely that the pre-drilled holes aren’t going to lineup exactly so you may have to enlarge the holes to get everything aligned. When you’re satisfied things are aligned, level and equally spaced, epoxy the spars to the center section. After the epoxy cures, glue on the floats.
Wing
Build the wing just as described in the directions. The only change is to notch the front center so the wing will fit over the pylon and wires from the ESC.
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