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Sig Mfg. Co., Inc...401-7 South Front Street....Montezuma, Iowa 50171
The King Kobra was designed to fill requests for a .60 sized airplane like our popular .40 - .50 size Kougar. Following the Kougar
philosophy, it is a compact model. Because of this efficient size, the King Kobra is capable of excellent aerobatic performance
without necessarily needing a tuned pipe and/or retracts. We know there will be some builders who will want to use these high
performance extras so a section is included in these instructions to guide them. The kit, however, is intended to produce the
fixed gear version as it will be built by the majority of buyers. Any extra parts or materials needed for retracts or tuned pipe
installation are not supplied.
It should be obvious that this is not a model for novice fliers. You can't go straight from a high wing trainer like the Sig Kadet to
the King Kobra without a lot of assistance from an instructor. But if you travel the full 3-step "Learn To Fly RC The Sig Way"
program or its equivalent first, the transition to the King Kobra's high speed and responsive performance will be easy.
Since most builders of this kit will probably have had some experience we were tempted to short cut the instructions. This was
not done. Some skilled fliers may not have had much prior building experience and beginners at both building and flying will
probably be constructing the model for future use. Other readers with considerable expertise may feel they can skip the
instruction book. Our advice is the same as to the amateur. Read it all before beginning. There are some essential facts mixed in
with the more elementary, don't get bored and miss these.
ABOUT THE BUILDING SEQUENCE
The quickest and most efficient way to complete a model is to work on several pieces at the same time. While the glue is drying
on one section you can start on or proceed with another part. Work can even go forward on several sections of the same
assembly at the same time, such as the front and rear of the fuselage. We occasionally get suggestions that our instruction
books should be in exact step-by-step building sequence. But this would result in many sentences starting, "While the glue is
drying on the fuselage, move to the wing etc." and a lot of jumping back and forth between assemblies with no consistant pictoral
progression. Also, our pre-selected building sequence might not suit your workshop space or time allotments.

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Summary of Contents for SIG King Kobra

  • Page 1 It should be obvious that this is not a model for novice fliers. You can't go straight from a high wing trainer like the Sig Kadet to the King Kobra without a lot of assistance from an instructor. But if you travel the full 3-step "Learn To Fly RC The Sig Way"...
  • Page 2: Wing Construction

    Tape 6 sheets tightly together with strips of masking tape. Turn over and open up the joints, with the masking tape serving as a hinge. Put a bead of Sig Bond in each of the seams and close the joint.
  • Page 3 CAUTION: Use only Sig Core Bond, Sig Kwik-Set, Sig Epoxy Glue or Sig-Bond Glue on the foam wing cores. Model cement such as Sig-Ment, dope and fiberglass resin will attack and destroy foam. If you use any product other than those listed, test them on a scrap of foam.
  • Page 4 Sig Core Bond doesn't cause this type of damage so it is ideal for the wing will be bowed or twisted. And beginners at foam wing sheeting in addition to being a superior adhesive.
  • Page 5 15. Roll the core down onto the sheet with a rocking motion. 16. Continue rolling the core onto the sheet until the leading edge is attached. 17. Turn the core over and firmly rub down the wing skin sheeting with the flat of your hands to insure that the balsa skin is firmly attached to the core.
  • Page 6 Sand the wing ends (Photo 29) as required to make the center joint fit correctly together. Glue the halves together with Sig Epoxy Glue or Sig Kwik-Set Glue. Use plenty of glue where the balsa sheeting meets so that the joint between the two halves is completely filled.
  • Page 7 34. Epoxy the PW tabs in place, using a ruler to line them up with the wing top surface. 35. Drill holes in PW for aileron horn. 36. Epoxy the brass tubes to the wing trailing edge, using pins to hold the horn wires in alignment. I find that gluing the tubes directly to the wing puts the horn a little too close.
  • Page 8 46. Carve the blocks roughly to shape so that the contour of the fuselage is carried on to the wing. a. Glue the blocks to the wing and fine sand the shape as shown. b. Fill any small remaining gaps with Sig Epoxolite or a mixture of Sig Kwik-Set glue and micro-balloons or talcum powder.
  • Page 9 Cut strips of 2" fiberglass tape for both sides of the wing center joint. 49. We use regular Sig Epoxy Glue (not Kwik-Set Glue) for applying the fiberglass tape, since it is thinner and easier to spread out smoothly. It will be even easier to spread if you warm the mixing container by setting it in hot water for a few minutes to raise the temperature of the glue.
  • Page 10 Hook the servo to the aileron horns with the rods and RC links. c. A servo connector can be used at the other end instead of a "Z" bend, if desired. The Sig SIGSHl84 connector is shown here but is not furnished in the kit.
  • Page 11 Since the firewall is 3 laminations thick, this was Sand the gloss off and roughen the plastic in the areas where the Sig no big deal, there was still plenty of Epoxolite putty will be applied. (The putty will almost become an integral wood left to do the job.
  • Page 12 - that we recommend the Goldberg for the King Kobra. b. Position the motor on the mounts so the spinner backplate will be 4-7/32"...
  • Page 13 65. Be sure and epoxy the blind nuts to the back of the firewall so they will not come out later when it may be necessary to take off the mounts. Work some under the nuts but don't get epoxy into the threads of the bolts. Pull the blind nut points tight into the wood with the bolts before the glue sets up.
  • Page 14 CAUTION: Epoxy or gap-filling cyanoacrylate glue is recommended for FD. Water base glues such as Sig Bond, Tite Bond, Elmer's, etc. may cause curling because of the large are a being glued. Spread a thin film of epoxy with a paddle.
  • Page 15 82. Continue forward gluing F-4. 83. Add F-3. 84. Prepare F-2 in advance, using the pattern, with dowel holes drilled and doubler installed. For fixed gear airplanes, cut out an access hole to the nose for inserting the battery if balancing requires this. 85.
  • Page 16 93. Bend the tubes of the tank so they point directly forward. Drill holes in the firewall to pass them. If you have trouble bending tubing try K&S 1/8" Soft Brass Fuel Tubing. 94. Put a scrap wood block on each side of the nose to hold the tank in place. 95.
  • Page 17 When everything is fitted, FT can be glued in permanently. Sig-Ment may be used to fasten on the fuselage top. Don't put on large blobs - they may melt the plastic. Work quickly or the Sig-Ment will get too dry and not stick properly. "Super" cyanoacrylate glues are handy for attaching the top. Put it in place and run the glue under the seam between the plastic and the gluing rail.
  • Page 18 Optional Wing Fillet On the original prototypes, a small wing fillet of Sig Epoxolite was installed. The main purpose of this was to make a good seal at the wingfuselage joint. It was put on after the model was covered with Koverall and clear doped. On models with plastic film covering, fillet first.
  • Page 19: Tail Surfaces

    TAIL SURFACES NOTE: The design of the stabilizer-fuselage joint includes a simple method of insuring proper incidence alignment of the tail. Make sure you understand it before proceeding. Study the pictures and drawings. The 1/4" sq. main frame of the stabilizer in the center at front and back is left exposed in order that it can be mounted directly on the fuselage.
  • Page 20 118. Remove the assembly from the plan. Turn it over. Glue the 1/8"x318" spar in place on each half. 119. Remove the temporary cross pieces and complete the spars. 120. Cut 1/8" scrap pieces. Glue in place. (Provides gluing area for sheeting around the keying gap.) 121.
  • Page 21 129. Shape the elevator stock in the same manner as previously shown for the aileron stock. We are asked why so many parts are used for the sheet tail when it would 130. Cut out the tail parts. Fit them together using the sanding block. Glue and pin be easier to make it with a single grain them down on wax paper.
  • Page 22 RETRACTS Because the King Kobra is a compact aircraft there is not a lot of wasted space in which to loose a retract unit. But that's better than having room to spare and the extra drag that goes with it. We designed the model first and found a way of fitting the gear into it, which seems to be a better approach than designing an airplane around a retract gear, particularly since the majority of King Kobras will be built by sport fliers.
  • Page 23 Full size drawings on the plan show the amount of space available for the nose units. Make certain that both the mounting and nose gear steering methods of the units you select will adapt to the King Kobra before buying them. There should be no space problem in the wing for most any kind of retract units.
  • Page 24 146. a. Brace the mounting plate to the NOTE: sides with triangular stock There is not much room for the Spring Air steering arm in the nose. In the through the mounting plate and installation shown in the following pictures the situation was carried to the tank floor.
  • Page 25 163. Soak the sheet wood in water until it is pliable and bend it into place. 164. This shows the air tank and control valve installation in one King Kobra. The servo for the valve was put on the wall of the...
  • Page 26: Nose Gear Installation

    Below: screws. This installation has easy The radio installation in the King Kobra. The receiver and battery have been access to the screws, but the pipe is at a wrapped in Sig Foam Rubber.
  • Page 27 Brush a coat of clear dope (Sig Supercoat, Sig Lite Coat or Sig Nitrate, depending on the final finish to be applied) on all parts of the structure that will touch the covering. When the dope is dry, sand lightly to remove any raised fuzz or grain.
  • Page 28: Color Schemes

    Plastic may also be painted with Sig Skybrite, Sig Plastinamel, K & B Superpoxy, a number of coats. (The rest of the Hobbypoxy or Du Pont Dulux Enamel. Don't use other paints without testing first fuselage will not show this effect to on scrap plastic.
  • Page 29 NO.2 shows the red-winged F-16 style No. 3 is a more complicated version straight lines. The red top wing tip and King Kobra. A variation would be to with curves. The span-wise stripes are stabilizer tip stripes are brought around leave the wing center section white blue, the fuselage spear is red.
  • Page 30: Control Movements

    Balancing The King Kobra design, like the Kougar, requires a farther forward balance point WHY MODELS MUST BE than commonly used on some other pattern style designs. Do not decide on the...
  • Page 31 LIMIT OF LIABILITY: In use of our products, Sig Mfg. Co.'s only obligation shall be to replace such quantity of the product proven to be defective. User shall determine the suitability of the product for his or her intended use and shall assume all risk and liability in connection...