Building Instructions

Congratulations for getting the Tomahawk II flying wing. We made several improvements to Tomahawk I, resulting in better handling, improved recovery after a collision in combat and more resistance to tip stall. We hope that this high performace combat wing will bring you plenty of fun.

This kit contains:

EPP wing halves                      2 ea.

Coroplast stabilizers                 2 ea.

Balsa elevons                           2 ea.

Control horn sets + clevises       2 ea.

Elevon pushrods                        2 ea.

This instruction manual               1 ea.

Other things you will need:

50 mm packing tape (see text) in your favorite colors

1 roll filament (strapping) tape

1 small 3M77 spray adhesive can

1 small set of 5-15 min epoxy or medium to thick CA

R/C system, capable of mixing (DELTA nebo ELEVON); 2 standard servos

usual tools, i.e. x-acto knife, sanding block, drill, straight edge 50 cm

1. wing assembly

Lightly sand the wing halves, join them using epoxy or CA

Most CA glues should not damage the EPP surface; to be sure, apply a little drop of CA first and see what happens

2. radio installation

During the lifetime of your Tomahawk, the radio gear will be an integral part of the model (you can make the receiver removable though). The R/C parts are located in the wing according to the Fig. 1. You may use 270 to 600 mAh battery pack. 600 mAh is better as you may fly longer and the extra weight of the battery will help you balance the wing. Standard servos are used; you are likely to damage micro servos in slope combat. The transmitter must be equipped with the necessary mixing (DELTA or ELEVON), or you can use some onboard electronic mixer.

Mark an outline of the R/C components for a tight fit. Cut down on the line with hobby knife in the appropriate depth. Use a flat screwdriver to dig out the foam for a good fit. Servos are situated in the wing according to the Fig. 2; you may cover them by a scrap of EPP or styrofoam and sand it flush with the wing surface. Servo horns have to move freely, without mechanical constraints. They should not exceed the wing surface by more than few millimetres as they (or the servo gear) might be damaged in combat. The servos and the battery are fixed in the cavities by few drops of CA or some hot glue or epoxy. Cut shallow grooves for all the wires. Don´t use any switch, just connect the wires (the battery wire to a short extension wire connected to the receiver) to switch on the system.

3. covering the wing

Lightly sand and vacuum both sides of the wing.

Use masking tape for temporary cover of the R/C gear components. Apply light spray of 3M77 on the leading edges of the wing. Set it aside for 10 - 15 minutes.

Apply some 70 mm long pieces of strapping tape on the leading edge of the wing (see Fig. 3). You should pull the tape in the process, to compress the EPP material of the leading edge. This way, the LE recovers better after an impact.

Apply another spray of 3M77 on the wing and set aside for 10 - 15 min more.

Lay 10 - 15 mm wide strips of strapping tape (see Fig. 4). Pull the tape to "compress" the wing a bit, make sure that you don´t twist or warp the wing though. You may check the geometry of the wing by placing it inverted on your workbench: the trailing edges should equally follow the surface of the desk. In this stage you may correct the geometry by removing and re-applying the strips.

Lay another strip of 25 mm wide fiber reinforced tape over the leading edge, see Fig. 5.

Apply another light coat of 3M 77 and let it tack up for for 10 minutes. Cover the wing in packing tape in your favourite, eye-pleasing color scheme. We prefer the tape  that has the least transparent sticky layer - you are likely to get more uniform color on the wing this way. Keep checking the wing for warp and/or twist when laying the packing tape.

Sand a bevel to the front edge of the elevon for free movement, see Fig. 6.

Lay 25 mm strapping tape over both sides of each elevon, spanwise. Cover elevons in packing tape or Oracover. Mount control horns with clevis holes over hinge line. Attach the elevon to the wing using 18 pcs of "combat hinges". Combat hinges are made each from two strips of strapping tape, 0,5 cm wide and some 2 cm in length. These strips are attached sticking sticky sides together, overlapping some 5 mm. See Fig. 7. The elevon is not flush with the wing tip, leaving some 2 mm clearance.

Cover the upper hinge line with clear tape while the elevons are 30° down (otherwise you would limit the the elevon movement).

4. finishing

Cut 2 slots into each winglet, attach the winglets to the tip of the wing using strips of filament tape (see Fig. 8). The winglets should not get in contact with the moving elevons.

Control rods are attached to the elevon control horns using the clevises included in the kit. To the servo horn, the rods are attached using a "Z-bend".

In the neutral position, the elevons are approx. flush with the bottom surface of the airfoil and/or up to some 3 mm up from this position.

The wing is balanced some 20 cm from the nose (leading edge). You should use this setting for the first flight, later you can experiment with the CG location (but 20 cm is the location we prefer and you shouldn´t get too far from this). For temporary balancing, we use flat pieces of lead with sticker layer (used to balance car wheels).

Contol throws: for the test flight, set 20 degrees movement for both elevator and aileron function. Eventually you should use some 120% rate for ailerons and 80 % for up elevator. Down movement for elevator should be some 20 - 30 %  more than up, as you sometimes have to quickly recover the plane into an inverted flight after a combat collision. If you don´t have these advanced radio features, try to increase the test flight setting throws as long as the plane doesn´t spin out after a full pull up on the elevator (in fast flight).

More tips, pictures of building and flying Tomahawk II and other models you can see on www.rcmania.cz.

Be friendly on the ground and aggressive in the air!

building tips with photos

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