Tantrum Specifications8 Mountain Models Tantrum Assembling the Horizontal Stabilizer Putting the pieces together 1. Remove the pieces shown in black from the balsa sheet. To remove

Tantrum Specifications

Wingspan: 37in. (94cm.) Length: 37in. (94cm.) Wing Area: 370in2 (2388cm2) Weight (without battery): 10oz. (255g.) Wing Loading (depending on battery): 5.0 – 6.0oz/ft2

Mountain Models Tantrum 2

Revision History

Date Revision Notes/Comments

6/1/03 Document initial creation.

8/12/03 Changes to reflect kit changes

10/12/03 Added new canopy

Thank you for purchasing the Tantrum. This plane was designed for the pilot who wants something more than the everyday parkflyer, and that when using proper mixing, is 3D capable.

Please keep in mind that this plane is an aileron/elevator/rudder (full house) setup, intended for the intermediate to advanced pilot. It’s intended to be flown in limited space situations, without sacrificing its outstanding performance capabilities.

Sincerely,

Doug Binder [email protected]

Mountain Models 6975 Blackhawk Place Colorado Springs, CO 80919

www.mountainmodels.com Phone: 719.592.1387 Fax: 719.528.6125 For the most up-to-date information, please refer to our Web site.

Created by Ross Design Group for exclusive use by Mountain Models.


Before You Begin

Before you begin building your Tantrum make sure you read and understand all of the instructions thoroughly.

Additionally, you will need to have the following items. Check to make sure that all of your parts are there and in good shape, and review a couple quick building tips to make this whole process go quicker and easier.

What You Will Need • Smooth and flat work surface

• Wax paper to protect the plans

• Thin and thick Cyanoacrylate (CA) glue

• Hobby knife with #11 blades

• Needle nose pliers

• Wire cutters

• Sanding block with 200 grit sandpaper

• 90° triangle or small square to true the bulkheads and fuselage

• Covering material

• Sealing iron for applying the covering

• Clear packing tape for hinges

• 5 channel computer radio with aileron/flap mixing, or a 4 channel radio with a Y cable for the two aileron servos

• 4 or 5 channel receiver

• GWS EPS300C-D motor with a 12x6 propeller

• 4 micro servos (we recommend either the Hitec HS55s or the GWS Picos)

• Electronic Speed Control (ESC) capable of handling at least 10 amps

• Battery pack (we recommend you use at least the following):

♦ 8 cell 600 mAH NiCd (configured )

♦ 8 cell 950 mAH KAN NiMH (configured )

Parts List

The following tables list all of the pieces that are in your Tantrum kit.

Description of Parts

Wood

Figure A: 1/8" laser cut balsa sheet



Wood

Figure B: 1/8" laser cut balsa sheet

Figure C: 1/16" laser cut balsa sheet

Figure D: 1/8" laser cut balsa sheet

Figure E: 1/16" laser cut balsa sheet

Figure F: 1/16" laser cut balsa sheet

Figure G: 1/16" laser cut balsa sheet

Figure H: 3/32" laser cut balsa sheet



Wood

Figure I: 3/32" laser cut balsa sheet

Figure J: 1/32" laser cut balsa sheet

Figure K: 1/16" laser cut plywood sheet

Figure L: 1/16" laser cut plywood sheet

Figure M: 1/64" plywood sheet

Figure N: 1/4" laser cut balsa for cowl

Figure O: 1/4" square x 18” balsa leading edge (x 2)

Figure P: 1/64" plywood sheet


Number in Kit

Description of Part

Wire

1 1/16" x 14" landing gear wire

1 1/32" x 18" thin music wire for the tailskid and pushrods

Plastic

1 Canopy

Bagged Parts

1 1/8" round x 2.75" hardwood dowel

1 6" x 3/32" heat shrink tubing for the pushrods

2 Internal star washers for wheel retainers

2 3/32" x 3/4" aluminum tube wheel axles

1 6" Velcro strip for mounting the battery and receiver

1 6" double-sided Velcro strip for battery strap

1 1-1/2" clear mushroom head Velcro for canopy closures

2 Wheels

1 Spectra thread (65 pound strength) for pull-pull system

6 Micro pushrod adjusters

4 Cotter pins for the pull-pull cables

2 #2 x 3/8" motor and battery mount retaining screw

2 4-40 wing bolts

4 Washers for the wing assembly

1 Neodymium canopy hold down magnet with tack

2 Nylon insert locking nuts

General Building Tips • Tape your plans to the work table, and then cover them with wax paper to

protect them.

• Balsa is a lightweight and fragile wood, so you do need to be careful with it; however, you will also need to use a little bit of force to make everything fit properly, so don't be too timid.

• Join all of your pieces using thin CA (cyanoacrylate) glue, unless we tell you otherwise. In general, only a small amount of CA is necessary to glue parts together.

• Don't remove any pieces from the balsa sheets until they're ready to be used. That way, parts won't get mixed up or disappear.

• After you remove pieces from the balsa sheets, carefully remove any of the extra material from where the piece was attached.

• Don't force your pieces together. If they aren't going together properly, make sure you have the right pieces and that they are oriented correctly.

• If you want to remove the charred edges caused by the laser cutting process, dampen a cloth with bleach and gently rub the affected areas. Removing the char will not increase the strength but will make it look better.


Assembly Instructions

Okay, so now you are ready to actually build the Tantrum. If you follow these simple instructions, we can have you flying in no time!

The Entire Process Demystified Step 1: Prepare your workspace for assembly.

Step 2: Assemble the stabilizers, rudder, and elevator.

Step 3: Assemble the ailerons.

Step 4: Assemble the wings.

Step 5: Assemble the fuselage.

Step 6: Assemble the landing gear.

Step 7: Sand, attach the canopy mounts, and cover all your pieces.

Step 8: Install the elevator and rudder servos

Step 9: Attach the control horns

Step 10: Attach the elevator, stabilizers, and the rudder.

Step 11: Install the aileron servos.

Step 12: Install the motor.

Step 13: Attach the wings.

Step 14: Attach the electronics.

Step 15: Finish the kit up with the canopy, batteries, throws, center of gravity, and the landing gear.

Final Step: On a calm day, find a field without too many trees or light poles and go fly.

Trees and light poles REALLY like to munch on remote control planes. We say this from experience…trust us.

Step 1: Preparing Your Workspace for Assembly Before you begin assembling the Tantrum, you must prepare your workspace.

! Making space in what is probably the most crowded place in your home

1. Lay out the plans on a flat worktable, and then tape them down.

2. Cover the plans with a sheet of wax paper. This will protect the plans from glue.

Step 2: Assembling the Stabilizers, Rudder, and Elevator The first things that you are going to assemble are the stabilizers, rudder, and elevator. When assembled, these are also known as the tail feathers.

Necessary Pieces

• 1- 1/8" laser cut balsa sheet (Figure A)

• 1- 1/8" round x 2.75" hardwood dowel (Bagged Part)


Assembling the Horizontal Stabilizer

! Putting the pieces together

1. Remove the pieces shown in black from the balsa sheet.

To remove the pieces, gently flex the balsa sheets until the pieces fall out. You may find that you need to carefully remove the extra pieces of wood that originally held the piece to the sheet.

2. Position the pieces as shown below. Using the interlocking tabs and grooves, begin connecting the pieces together to form the horizontal stabilizer.

Assembled Horizontal Stabilizer

Once the pieces are connected together you should be able to fly it around the room making airplane noises...yes, I do mean BEFORE you add the glue!

The pieces are pretty snug when you are trying to fit them together. Use about the same amount of pressure as you would on a jigsaw puzzle, unless of course you don't like jigsaw puzzles and tend to smash the pieces in…in that case, be MUCH more gentle then putting together a puzzle.

3. Using just the tip of your CA applicator, apply a drop of thin CA to each of the joints. The glue will be wicked into the balsa to form a secure bond, so it won't take much glue to do this. Make sure that you are only working on one joint at a time, and that the pieces are firmly connected before moving to the next joint.


Be careful to keep your fingers as far away from the glue as possible; otherwise, you might become a part of the model permanently. If you do get stuck, remove yourself as carefully as possible, trying to avoid taking any of the wood with you. Once separated, remove the CA glue from your fingers using nail polish remover, or acetone, making sure you wash your hands thoroughly when done.

4. Once the parts are dry, carefully remove them from the wax paper.

5. Bevel the trailing edge 45°. This should ONLY be done on one side of the piece, and only for the bottom edge.

Horizontal Stabilizer with Bevel Guide

• To bevel or taper the piece, place it on your worktable with the edge you are working on lining up with the edge of the table. Using one bar sander to hold the piece down, use another bar sander to do the actual sanding.

• While sanding, try to go over the entire edge in a sweeping motion, avoiding any part of the assembly that is to remain non-beveled. This will make sure that your bevel angle is even across the entire way.

• Make sure that you sand lengthwise with the grain and not across it, as this will cause less strain on the wood and less chance of breaking the pieces.

• Using a tack cloth, carefully remove the balsa dust once you are done sanding.

Assembling the Vertical Stabilizer The process for the vertical stabilizer is pretty much the same as for the horizontal stabilizer; therefore, the following section is mostly for reference purposes, so you can refer to the pictures as necessary.




2. Position the pieces and begin connecting them together to form the vertical stabilizer.

Assembled Vertical Stabilizer

3. Glue all of the joints, following the process described for the horizontal stabilizer.


Assembling the Rudder



2. Position the pieces and begin connecting them together to form the rudder, as shown in the following image, and then glue all of the joints.


4. Bevel the entire leading edge 45°. This should ONLY be done on one side of the piece.


Assembled Rudder with Bevel Guide

Assembling the Elevator



2. Position the pieces and begin connecting them together to form the two halves of the elevator.

Assembled Elevator (Right Side)

The two halves of the elevator are identical to each other, one is simply the opposite side of the balsa sheet. In other words, once the elevator halves are together, simply flip one over, so it is the mirror image of the other one.

3. Glue the joints for each of the elevator halves, using thin CA.


4. Join both the halves with the provided dowel, gluing it into place with thick CA.

Completely Assembled Elevator

Step 3: Assembling the Ailerons Once you have finished building the tail feathers, you can begin assembling the ailerons.

Necessary Pieces

• 1- 1/8" laser cut balsa sheet (Figure B)


1. Remove the Aileron 1 pieces shown in black from the balsa sheet.

Aileron 1

2. Position the pieces, and then begin connecting them together to form an aileron.

Aileron Assembly

3. Glue all of the joints, following the process described for the horizontal stabilizer.


5. Remove the Aileron 2 pieces shown in black from the balsa sheet.

Aileron 2

Dowel connecting the two elevator halves together.


6. Glue all of the joints, and once dry remove them from the wax paper.

7. Create a 45°° bevel into the leading edge of both aileron assemblies. This should ONLY be done on one side.

To get a left and a right aileron, make sure you lay out the ailerons so that both leading edges are facing forward, mirroring each other.

Ailerons with Bevel Guide

Step 4: Assembling the Wings Once you've finished building the tail feathers and the ailerons, you can begin assembling the wings. The wings are not interlocking, but do have guides to help you make sure things go together correctly.

The information within this section applies to building one wing at a time and then duplicating the entire process for the other wing. But if you want to, you can build both the wings at the same time. You must be sure to make a right and a left wing. This is a good reason to at least start the two wings at the same time.

Attaching the Wing Root and Tip Ribs to the Vertical Spar For each wing, you will need:

• 1 wing tip rib (Figure B)

• 1 vertical spar (Figure C)


• 1 wing root rib (Figure D)


1. Layout the pieces so you can see how things will line up.

2. Hold the vertical spar so that the slots are facing upwards towards the ceiling.

3. Slide the rib you removed from Figure D, known as the wing root rib, into the slot next to the cutout on the vertical spar.

4. Push the slot, located on the rib you removed from Figure B, known as the wing tip rib, onto the tab at the outside edge of the vertical spar.

This is where you can begin assembling the second wing, making sure that it's a mirror image of the first one. Did I mention that this was important??

Wing tip rib from Figure B

Wing root rib from Figure D Vertical spar from Figure C

Wing root rib

Wing tip rib


Attaching the Rest of the Wing Ribs to the Vertical Spar For each wing, you will need:

• 3 wing ribs (Figure E)

• 1 wing rib (Figure G)

The wing ribs are split across two different balsa sheets. For the second wing you are going to use two ribs from Figure E and one rib from Figure G.


• While you are still holding the vertical spar with the slots towards the ceiling, match up each wing rib slot with the remaining cutouts, and then slide them into place.

Wing ribs from Figure E


Adding the Fuselage Attachment Pieces For each wing, you will need:

• 2 plywood fuselage attachment pieces (Figure K)

These pieces are also used to reinforce the wings to the wings, but for the sake of not having to re-type a REALLY long name over and over, we're just going to call them fuselage attachment pieces for now.


1. On one of the ribs, you will slide the fuselage attachment pieces behind the vertical spar into the provided slots in the wing root rib.

2. Make sure that you line up the holes on the reinforcements.

When you are building the second wing, you will need to slide the fuselage attachment pieces in front of the vertical spar, into the provided slot in the wing root rib. Refer to the picture above for assistance.

Don't glue these joints together yet, you'll glue everything after the spar caps are attached. This is so that the CA doesn't over saturate the wood and cause strength issues down the road.

Attaching the Spar Caps For each wing, you will need:

• 2 spar caps (Figure F)

Fuselage attachment piece,behind the vertical spar



1. Attach the spar caps along the top and bottom of the vertical spar, matching the cutouts on the spar caps with the placement of the wing ribs.

Pay special attention to which end of the spar cap is facing towards the root of the wing, and which end is facing towards the wing tip. The wing tip should be flush along the side edge, with no overhanging wood.

2. Check to make sure that the rear of each rib is lined up with the other ribs and then

glue all of the joints, making sure that the ribs fit fully into both spars, that both spars are touching the vertical spar, and that everything is flush, snug, and square, including the wing reinforcements.

The Tantrum is meant to be a lightweight plane, so make sure you use the CA as sparingly as possible, but you shouldn’t sacrifice strength for weight.

Attaching the Stringers For each wing, you will need:

• 4 stringers (Figure D)


1. Slide each stringer lengthwise into the four slots at the end of each wing rib, making sure that they are flush with the wing tip.

Upper spar cap

Lower spar cap


2. Glue all of the stringers into place, making sure that all of the ribs are straight and

properly lined up within the stringers.

3. Cut the stringers flush with the wing root rib.

Attaching the Trailing Edge For each wing, you will need:

• 1 trailing edge (Figure D)


1. Line up the trailing edge with the slots at the end of the wing ribs, so that all of the slots and tabs fit together.

2. Make sure that everything lines up, push the trailing edge firmly against the ribs, and

then glue the joints.

Attaching the Leading Edge For each wing, you will need:

• 1/4" leading edge balsa stick

Trailing edge

Stringers



1. Use a small bead of thick CA glue on the remaining slot, located on the leading edge of each of the wing ribs.

2. Align the balsa stick with the outside edge of the wing, pushing it gently into place in the slots.

3. Hold the leading edge in place until the glue cures, and cut the leading edge flush with

the inner rib then sand the edge from root to wing tip, in order to match the profile of the wing rib. There will be extra wood overhanging the wing root that will need to be trimmed so that both sides are flush with the outside, as shown below.

Attaching the Aileron Servo Mount For each wing, you will need:

• 1 plywood aileron servo mount (Figure P)

Leading edge

Sanded leading edge, shown on wing tip side


• 2 plywood servo screw reinforcements (Figure L)

• 1 balsa servo mount reinforcement (Figure H)

! To put the pieces together

1. Using one of the plywood servo screw reinforcements from Figure L, line up its hole with one of the holes on the aileron servo mount, and glue it to the mount using thin CA.

Make sure you notice to which side the rectangles are being glued. This is really important, since the servo mount is attached underneath the wing with the rectangular pieces facing inside the wings.

2. Using the other servo screw reinforcement, perform the same process as Step 1, using the other available hole on the servo mount.

3. Mark a line 1/4" on the servo mount, following the guide shown below.

Aileron Servo Mount with Line Guidance

Both servo screw reinforcements attached to the aileron servo mount


4. Using thick CA, run a thin bead along the spar cap and lower wing rib edge, where they will attach to the servo mount once it's installed.

5. Line up the servo mount so that it’s flush with the fuselage-side edge of the wing root rib, and that the line you marked in Step 3 is even with the trailing side of the lower spar cap, and hold until the glue has cured.

6. Using the balsa servo mount reinforcement from Figure H, line it up on the servo

mount at the point where the square side and the angled side meet. Make sure it’s perpendicular and butted up against the inside of the root wing rib, and then glue the joints.

Attaching the Wing Reinforcements For each wing, you will need:

• Wing reinforcements – 3 Long, 1 Short (Figure H)

Attached aileron servo mount – wing root side

Balsa servo mount reinforcement piece

Upper spar cap

Lower spar cap


• Wing reinforcements – 3 Long, 1 Short (Figure I)


1. Underside of the Wing Root Side: Using the short wing reinforcement piece, butt it up against the trailing edge with the length of it facing toward the balsa servo mount reinforcement, and then glue it into place. See image below.

Before you glue any of the wing reinforcements in place, make sure they’re aligned with the trailing edge, and that they aren’t sticking out at any weird angles.

2. Topside of the Wing Root Side: Using one of the long wing reinforcement pieces, butt it up against the trailing edge, making sure that the “fingers” are meshed together with the short wing reinforcement piece you glued in Step 1.

3. Glue the long wing reinforcement into place.

4. Underside of the Wing Tip Side: Using one of the long wing reinforcement pieces, butt it up against the trailing edge and glue it into place.

5. Topside of the Wing Tip Side: Using the last of the long wing reinforcement pieces, butt it up against the trailing edge, making sure that the “fingers” are meshed with together with the wing reinforcement you glued in Step 4.

Short wing reinforcement piece from Step 1

Long reinforcement piece from Step 2

Meshed "Fingers"

Upper spar cap


6. Glue the long wing reinforcement in place.

Repeat all of the wing assembly steps for the other wing, making a mirror image of the one you just completed. Unless of course, you built both at the same time, in which case you get to move on the fuselage.

Step 5: Assembling the Fuselage Once you've finished building the wings, you can begin assembling the fuselage. This involves assembling the fuselage sides and bottom, attaching the bulkheads and tail piece, assembling and attaching the motor mount supports, and finally, attaching the motor mount itself.

Assembling the Fuselage Sides For each fuselage side, you will need:

• Fuselage pieces (Figure I)

• Matching fuselage pieces (Figure H)

Each fuselage side is on a different balsa sheet. The first side uses all of the remaining pieces from Figure I, while the second side uses the

Long reinforcement pieces

Meshed "Fingers"Upper spar cap


matching pieces from Figure H. There should still be pieces on the Figure H balsa sheet.

! Putting together the fuselage sides


2. Position and connect the pieces as shown in the following picture, using the interlocking tabs and grooves to form one of the fuselage sides.

The center pieces, labeled A, B, and C should be used in alphabetical order from front to back on each fuselage side. The lettered portion of the piece should connect to the upper portion of the fuselage side. Additionally, the piece labeled “C” should actually connect at the bottom of the back piece.

3. Using the matching pieces on Figure H, repeat Step 2 to create the other fuselage side.

4. Glue all of the joints on both fuselage sides.

For additional strength, you may want to flow CA into where the wings connect with the fuselage

Assembling the Fuselage Bottom You will need all of the bulkhead pieces shown in the next picture, but these pieces are also shown again in each step, highlighted so you know which pieces are being used at each step.

The following image shows the bulkheads with codes that will be referred to on both the plans and in this section.

Attaching the Fuselage Tail The fuselage tail attaches at the rear of the fuselage bottom.


• Fuselage tail and Fuselage bottom (Figure G)

! Attaching the tail

1. Line up the tail piece with the rear edge of the fuselage bottom, matching the point and the cutout, as shown in the following picture.

2. Glue the fuselage tail in place.

Reinforcing Bulkhead F2 You will need to reinforce the F2 bulkhead, using pieces you remove from these balsa sheets:

• Bulkhead F2 (Figure C)

• Bulkhead Reinforcement (Figure G)


• Bulkhead reinforcement (Figure H)

• Bulkhead reinforcement (Figure F)

• Bulkhead reinforcement (Figure D)

! Reinforcing the bulkhead

1. Position the top bulkhead reinforcement from Figure G onto the front of bulkhead F2, matching the curve and notches, and then glue it into place.

2. Position the F2 bulkhead into the slot on the fuselage bottom, as shown in the

following picture.

Top bulkhead reinforcement - Front


3. Make sure that the bulkhead is perpendicular to the fuselage bottom, and that the reinforcement piece is facing to the front, and then glue it in place.

4. Position the bottom bulkhead reinforcement from Figure G onto the front of bulkhead F2, matching the curve and sides, and then glue it into place.

5. Position the bottom bulkhead reinforcement from Figure H on the back of bulkhead F2,

matching the reinforcement’s legs with the fuselage cutout, and then glue it in place.

6. Position the bottom bulkhead reinforcement from Figure F over the top of the

reinforcement piece you glued on in Step 5, match up the edges, and then glue it into place.

Bottom bulkhead reinforcement - Front

Bottom bulkhead reinforcement - Rear

Bottom bulkhead reinforcement, on top of previous piece


7. Position the bottom bulkhead reinforcement from Figure D at the base of the reinforcement piece you glued on in Step 6, and then glue it into place.

For some reason, the CA glue decided that fingers were yummy during this step, and tried to become “one” with them…if this happens, carefully pull your fingers away from the wood and remove the excess from your fingers with acetone. Wash your hands though…if you touch the CA with acetone on your hands, you run the risk of loosening the bond.

For additional strength you may want to flow CA into the slot under the F2 bulkhead, since this is where the landing gear is going to attach later.

Attaching the Battery Mount Support to Bulkhead F3 The battery mount support attaches to bulkhead F3, and requires only one piece from Figure L.

• Bulkhead F3 (Figure E)

• Plywood Rear Battery Mount Support (Figure L)

Bottom bulkhead reinforcement – Base on rear


! Attaching the battery mount support

1. Position the rear battery mount support from Figure L into the notches at the center of bulkhead F3, and then glue it into place making sure that it matches the following picture.

2. Position the F3 bulkhead into the slot on the fuselage bottom, as shown in the

following picture.

For additional strength, you may want to flow CA into the holes in bulkhead F3, these are going to be used for routing the pull-pull cables later.

Rear battery mount support


3. Make sure that the bulkhead is perpendicular to the fuselage bottom, and then glue it

in place.

Assembling the Fourth, Fifth and Sixth Bulkheads The fourth, fifth, and sixth bulkheads can all be assembled at the same time, using pieces you remove from these balsa sheets:

• Bulkhead F4 (Figure G)



! Assembling the bulkheads

1. Before you begin assembling, you need to flow thin CA around the lightening holes of the F6 bulkhead. This is to strengthen it so that the Pull-Pull cables do not cut into the wood.

2. Position F4, F5, and F6 into the fuselage bottom slots, as shown in the following picture.

F3 bulkhead

F2 bulkhead


Attaching a Fuselage Side You need to attach the fuselage sides you created previously around the fuselage bottom.

! Assembling the fuselage sides

1. Line up each bulkhead with the slots on the fuselage side, push it into place, and glue the joints back to the F6 bulkhead.

Be careful pushing the pieces together, while you do have to use some gentle pressure to get it to fit, if you push too hard you may break something. If something does break, a little CA never hurt. While we don’t recommend using too much, since it adds weight, don’t worry if you have to fix a piece or two while you are building…it happens to the best of us.

Inserting the Servo Mounts and Attaching the Other Fuselage Side You need to insert the servo mounts into the fuselage. This needs to be done while the F3 bulkhead is still able to flex.

Bulkheads F4, F5, and F6 in position


• 2 servo mounts (Figure D)

! Inserting the servo mounts and finishing the fuselage sides

1. Position the two servo mounts into the two slots just in front of the F3 bulkhead on the glued fuselage side.

2. Position the other fuselage side, making sure that everything lines up and that the servo mounts are in the opposing two slots on this side.

3. Glue the joints on the second fuselage side back to the F6 bulkhead.

Reinforcing Bulkhead F3 You will need to reinforce the F3 bulkhead, using one piece from Figure G.

• Bulkhead reinforcement (Figure G)

! Reinforcing the bulkhead

• Position the top bulkhead reinforcement from Figure G on the back of bulkhead F3, matching the curves, and then glue it into place.

Servo mounts installed with both fuselage sides attached


Attaching the Final Bulkhead For the final bulkhead, you will need:

• Bulkhead F7 (Figure F)

! Attaching the bulkhead

1. Position the bulkhead between the fuselage sides, inserting it into the rear most slots.

2. Glue the bulkhead into place, and then finish gluing the rest of the fuselage sides and

rear joints.

Attaching the Bulkhead Stringer The bulkhead stringer goes from the F7 bulkhead back to the rear of the fuselage.

• Stringer (Figure D)

F7 Bulkhead

F3 bulkhead reinforcement


! Attaching the bulkhead stringer

1. Position the stringer so that its notch slides into the slot on the F7 bulkhead.

2. Center the piece on the rear of the fuselage, and then glue it into place.

Attaching the Wing Alignment Brace This piece is used to align the trailing edges of the two wings.

• Wing Alignment Brace (Figure D)

! Attaching the wing alignment brace

You aren't going to glue the wing alignment brace into position until after you cover the fuselage. It is described here for positioning purposes only.

• From the outside of the fuselage sides, slide the wing alignment brace through the fuselage body and into the slots just in front of bulkhead F3.

Bulkhead Stringer

Wing alignment brace in front of the F3 bulkhead

Servo mounts


Attaching the F1 Bulkhead

• F1 Bulkhead (Figure L)

! Attaching the F1 bulkhead

1. Position and connect the F1 bulkhead using the fuselage side's tabs and slots at the very front of the fuselage, and then tack the edges into place.

2. Position and connect the bottom of the fuselage with the F1 bulkhead using the tabs

and slots, and then tack the edges into place.

We recommend tacking the pieces in place, and not gluing anything solidly yet. This will give you some additional flexibility in the balsa while you are lining up the sides and bottom.

3. Using thick CA, place a small bead of glue along the bottom corners where the fuselage bottom, sides, and the F1 bulkhead meet.

We chose to use thick CA at the corners for its added strength. These spots are fairly stressed, so they need a bit more than average strength.

4. Flow thin CA around all of the joints to make sure that everything is glued solidly together.

F1 bulkhead


Inserting the Motor Mount Supports

• 2 motor mount supports

! Inserting the motor mount supports

1. From the outside of the fuselage sides, slide the longer motor mount support through the fuselage body and into the slots closest to bulkhead F2; and then slide the shorter support into the slots closest to bulkhead F1.

2. Make sure that they are centered and flush with the fuselage sides, and then glue into

place.

Assembling and Attaching the Motor Mount

• 4 motor mount pieces (Figure L)

Motor mount supports inside the fuselage


! Assembling and attaching the motor mount

1. Position the motor mount pieces into a 3D rectangle, using the tabs and slots on each piece.

2. Make sure that everything is square, and then glue the joints.

3. Sand the motor mount so that it slides snuggly into the motor mount support holes, without forcing it into place.

4. Slide the motor mount through the square motor mount support cutouts, making sure that the cutouts on the motor mount are facing towards the F2 bulkhead.

5. Make sure that the rear of the motor mount is flush with the back of the larger motor

mount support, and then using thick CA, glue it into place.

Attaching the Fuselage Top Sheeting The sheeting is the balsa sheet that covers the tops of the bulkheads and forms the upper skin of the fuselage.

• Fuselage Top Sheeting (Figure J)

! Attaching the fuselage top sheeting

1. Spray the entire piece with a 50/50 mixture of water and alcohol so that it’s more flexible and less prone to splitting while you are manipulating the piece into place

Motor mount inside the motor mount supports


2. Form the sheeting over the tops of the bulkheads, lining up the smaller end with the F7 bulkhead, and the larger end with the F3 bulkhead.

3. Secure the piece into position using five rubber bands, one at each bulkhead.

4. Let the sheeting dry completely. Glue the underside of the sheeting where it meets each bulkhead, and to the outside edges of the fuselage sides.

5. Once the glue is dry, remove the rubber bands.

Attaching the Cowl Sheeting The cowl sheeting is exactly like the fuselage sheeting, but it only fits over the cowl area.

• Cowl Sheeting (Figure J)

! Attaching the cowl sheeting

1. Form the sheeting over the tops of the F1 and F2 bulkheads, lining up the smaller end with the F1 bulkhead, and the larger end with the F2 bulkhead.

The cowl piece is already attached and sanded here for reference and positioning purposes only, you should not have this attached to yours yet.

2. Secure the piece into position using two rubber bands, one at each bulkhead.

Cowl sheeting


3. Glue the underside of the sheeting where it meets each bulkhead, and to the outside edges of the fuselage sides.

4. Once the glue is dry, remove the rubber bands.

Assembling and Attaching the Cowl

• 3 cowl pieces (Figure N)

! Assembling and attaching the cowl

1. Glue the three 1/4" cowl pieces together.

2. Sand the front of the fuselage (F1 bulkhead), so that the cowl pieces will fit flush when attached.

3. Center the cowl pieces onto the F1 bulkhead, and then glue them into place.

4. Sand the front of the cowl to give it a nice rounded look, shown in the Attaching the Cowl Sheeting picture previously.

Step 6: Assembling the Landing Gear Once you've finished building the fuselage, you can begin assembling and attaching the landing gear.

Necessary Pieces

• 2 plywood landing gear reinforcements (Figure M)

• 1 balsa landing gear mount (Figure E)

• 1/16" x 13.5" landing gear wire (Thicker Wire)

• 2 wheels (Bagged Parts)


• Internal star washers for wheel retainers (Bagged Parts)

• 3/32" x 3/4" aluminum tube wheel axles (Bagged Parts)

! Assembling the landing gear

1. Lay one of the plywood landing gear reinforcements on the table, with the etched marks facing the ceiling.

2. Position the balsa landing gear mount so that the pieces line up with the edges of the plywood reinforcement piece, using the etched lines as a guide, and then glue them in place.

Use the landing gear wire to measure the gap between the balsa and plywood parts to make sure that it fits without being too snug or causing gaps.

3. Locate the center of the landing gear wire and bend it into a 70° angle, and then measure 3/4" from each end of the landing gear wire and bend a 125° angle into each. See the following picture for reference.

4. Insert the landing gear wire into the landing gear mount.

5. Position the other plywood landing gear reinforcement over the top of the balsa and plywood landing gear assembly you have created, making sure all of the edges line up, and then glue them together.

Once done, the balsa pieces and the landing gear wire should be encased within the plywood landing gear reinforcement pieces.

6. Roughen up the bent ends of the landing gear wire, slide one of the aluminum tubes over each end, and then glue into place.

Balsa landing gear mount pieces


7. Slide one wheel onto each end of the landing gear wire, over the top of the aluminum

tubes, attaching them on the outside with one of the internal star washers.

You will be attaching the landing gear assembly later, after you have covered and completed the kit.

Step 7: Sanding, Attaching the Canopy Mounts, and Covering The next step is to sand the pieces that need to be sanded, attach the canopy mounts to the fuselage, and cover everything.

We aren't going to go into how to cover the pieces themselves, you’re going to have to refer to your covering’s instructions for this information. Additionally, we aren't going to cover our kit for instructional purposes, since the covering hides too much.

Sanding the Tantrum What we recommend:

• 200 grit sandpaper for sanding

What to Sand This is a fairly small chore for the Tantrum, apparently the air prefers sharp edges to rounded ones, so we aren't going to round any of the pieces. Mind you, by sharp edges we don't mean pokey bits, you ARE going to have to sand those, we just mean non- rounded bits.

The only things that you need to sand, since you did the bevels previously, are listed in the following table.

What piece What to sand Wings • Sand the wing root and tip ribs to make sure that the stringers and

leading edge are flush with the face of the ribs. • Lightly sand the connection bits from where the pieces were

attached to the balsa sheets. • Lightly sand the spar caps so that they match the profile of the wing

ribs. • Make sure that there are no sharp edges that could tear your

covering while you are shrinking it. This CAN and WILL ruin your day if it happens, ‘cause it never seems to happen until you are almost completely done, and then you have to start over …or maybe that's just Murphy's Law…

Fuselage • Lightly sand the connection bits from where the pieces were attached to the balsa sheets.

• Make sure there are no sharp corners, and lightly sand any sharp edges off of all the pieces. Be really careful not to over-sand, you just want to remove the edges, you don’t really want to remove the

Aluminum tube on wire


material. • Put a gradual bevel into the rear of the fuselage where it will meet

with the rudder, just so that the width of the fuselage matches the width of the stringer on top of the F7 bulkhead.

• While sanding, try to go over the entire edge in a sweeping motion, avoiding any part of the assembly that is to remain non-beveled. This will make sure that your bevel angle is even across the entire way.

• Make sure that you sand lengthwise with the grain and not across it, as this will cause less strain on the wood and less chance of breaking the pieces.

• Using a tack cloth, carefully remove the balsa dust once you are done sanding.

Assembling the Canopy You are going to assemble and attach the canopy base, which once in place will be used to hold the plastic canopy in place.

! To put together the canopy

1. Trim the nubs from the canopy mount pieces, and then position the pieces as shown in the following picture.

2. Make sure that all of the pieces are perpendicular, and then glue the joints.

3. Cut out the front and rear-most sections of the plastic canopy.

4. Position the canopy mount inside the plastic canopy, lining up the rear of the mount with the rear of the canopy.

5. Using a fine point marker, mark the front, sides, and rear of the plastic canopy where it meets the canopy mount. Basically, trace an outline of the canopy mount onto the plastic canopy.

6. Cut out the plastic canopy, using the marks you created above.

7. Wash the canopy in dishwashing liquid. This removes the mold release and allows better adhesion for the glue.

If you plan on painting the canopy, you're going to have to do it before it's all glued in place. Once the canopy is washed, use a Scotch Brite pad to scuff the


plastic so that the paint adheres better. You should use the paint recommended for R/C car bodies (polycarbonate / lexan). This is also the time for you to paint the canopy frame.

8. Sand the canopy mount so it lines up flush with the inside of the canopy at both the front and rear, and then glue it into place using 5 minute epoxy. Do not use CA, it will crack the plastic.

Covering the Tantrum Determine what material you’ll use to cover, we recommend using Solite covering material since it is extremely lightweight and won’t crush the fragile balsa when shrinking.

Following your covering material instructions, cover the pieces in this order:

Do not shrink the covering until both sides of each part are covered. This reduces your chances of twisting the surfaces.

• Tail Feathers:

♦ Bottom and then top of the horizontal stabilizer. You don’t want to cover the center where it will attach to the fuselage.

♦ Bottom and then top of the elevators

♦ Entire Vertical stabilizer, except for the bottom where it attaches to the fuselage.

♦ Entire Rudder

• Fuselage:

♦ Sides of the fuselage

♦ Top of the fuselage

The bottom of the fuselage should not be covered now, it will be done after you route the pull-pull cables, described later.

• Wing:


♦ Bottom and then top of the wing. You don't want to cover where the wings connect to the fuselage; this is going to be inside the fuselage anyway, so there is no reason to make it "pretty". We recommend completely covering one wing and then doing the other, helps keep the rhythm.

• Ailerons

Cutting out the Covering After you've finished covering your pieces, you're going to need to cut out a few portions of the covering material, as follows:

• Cut out the elevator/horizontal stabilizer slot.

• Cut out the wing slots on both sides of the fuselage.

• Cut out the aileron servo access holes, right behind the wing slots.

• Cut out the openings for the rear wing alignment piece. Cut out only the top, bottom, and front. Fold the covering into the opening and tack it down.

• Cut out the vent underneath the servos for the rudder and elevator. This is for cooling purposes.

• Expose the bulkhead stringer where the vertical stabilizer will attach, this creates a stronger bond.

When you cut the covering, try to leave enough material so that you can fold it in to cover the edge of the balsa.

Gluing the Wing Alignment Brace The wing alignment brace was put in place within the fuselage earlier in this process, now it's time to glue it in place.

• Make sure that the alignment brace is centered, and then glue the joints.

We recommend flowing a bit of thin CA into the ends that are sticking out from the fuselage to make them stronger.

Wing alignment brace in front of the F3 bulkhead

Servo mounts


Step 8: Installing the Elevator and Rudder Servos You need to install both the elevator and the rudder servos inside the fuselage. The right servo, from the pilot’s POV is for the elevator, while the left servo is for the rudder.

To add strength, flow some thin CA into where the servos screw into the balsa servo mounts.

You will need:

• 4 Micro pushrod adjusters (Bagged Item)

• 2 Servos (Not provided with kit)

! Installing the servos

When using Hitec HS 55 servos, use the long thin arm with the small holes.

1. Before you install the servos, you should attach the micro pushrod adjusters to the outermost holes. It’s easier to do this before you actually install the servos; since you'll have to remove the control horns.

Install the servos so that one is facing one way while the other is facing the other way. This will ensure that the control horns don’t touch each other.

2. Position the servos onto the servo mounts so that they are straight, and then screw them into place using the screws that came with your servos.

Step 9: Attaching the Control Horns Next, you are going to attach all of the control horns, you will need:

• 1 Elevator control horn

Elevator servo

Rudder servo

Rear of Fuselage


• 1 Rudder control horn

• 2 Aileron control horns

! Attaching the control horns

• Elevator: Using the piece shown above, insert the control horn into the hole, making sure that it is to the right of the fuselage.

• Rudder: Using the piece shown above, insert the control horn through the slot on the rudder, positioning the control horn so that it's coming through the rudder evenly on both sides.

• Ailerons: Using the pieces shown above, insert one of the control horns so that its holes are facing where the wing will attach, into the same side that has the aileron servo mount. Repeat for the other aileron.

Step 10: Attaching the Elevator, Stabilizers, and the Rudder For this step, you are going to attach the elevator, the horizontal stabilizer, the vertical stabilizer and the rudder to the fuselage. When you are done, you will have a finished tail feather section!

Attaching the Elevator and the Horizontal Stabilizer 1. Insert the elevator through the slot at the back of the fuselage. You have to attach the

elevator before the horizontal stabilizer or you will NEVER be able to fit it into position.

2. Slide the horizontal stabilizer into place using the same slot as the elevator, making sure that it is forward of the elevator, and that it is perfectly centered and square to the centerline of the fuselage.

Elevator control horn

Rudder control horn

Aileron control horns


You can check that the horizontal stabilizer is perfectly centered by measuring the distance from the outermost point of the horizontal stabilizer trailing edge to the rear of the fuselage on both sides; the numbers should match.

Attaching the Vertical Stabilizer 1. Sand the front of the bottom of the vertical stabilizer so that it fits on the top sheeting,

and is flush with the bulkhead stringer.

2. Run a bead of thick CA along the top of the bulkhead stringer where the covering was removed, and position the vertical stabilizer, making sure that the rear of the stabilizer lines up with the rear of the fuselage and that it’s perpendicular to the elevator.

Attaching the Rudder

• Using clear packing tape, attach the entire leading edge of the rudder to the trailing edge of the vertical stabilizer. Make sure you attach the tape on the side without the beveled edge.

Elevator

Horizontal stabilizer

Vertical stabilizer Bulkhead stringer


Routing the Pull-Pull cables You will need:

• Spectra thread (65 pound strength) for pull-pull system (Bagged Item)

• 4 Cotter pins for the pull-pull cables (Bagged Parts)

! Routing the cables

The Spectra thread has a coating on it to make it waterproof. You will need to remove this coating where you tie off the thread to set the knot with CA. To do this, run the dull edge of a Xacto blade along the length of each thread.

1. Tie one end of the thread to one of the cotter pins, seal the knot with thin CA, and then remove the extra material.

2. Position a piece of clear scotch tape over the rear of the fuselage, where the cables are going to enter.

You are going to route two of the cables out of the bottom oval cutout on the right side of the fuselage, one cable out of the smaller oval cutout at the top on the right side of the fuselage, and one cable out of the bottom oval cutout on the left side of the fuselage. All sides are referenced from the POV of the pilot.

3. Make a vertical slit in the scotch tape, push the cotter pin through, and then guide it through the fuselage toward the cowl.

4. You will run the two lines that are going to connect to the outside control horns through the two small outside holes in the F3 bulkhead, one on either side.

5. You will run the two lines that are going to connect to the inside control horns through the large rectangular cutout underneath the rear battery mount support of the F3 bulkhead.

6. Route the cotter pins through the holes in the micro connectors for the appropriate control horn, push them through about 1/4", and then tighten the screws down.

7. Run the other end of the thread through the inner hole of the rear control horn. With the control surface straight back, tighten the thread and tie it off. Set the knot with a small drop of CA and remove the extra material.

8. Repeat for the other three cables.

9. Once you are done routing the cables, you can cover the fuselage bottom, just like you did all of the other pieces previously.


Step 11: Installing the Aileron Servos Next, you are going to install the aileron servos. These steps are for one aileron, so you just need to repeat the process for the other aileron.

For each aileron servo, you will need:

• Clear packing tape

• 1 - 1/32" x 18" thin music wire for the tailskid and pushrods

• 1 Micro pushrod adjuster

All of the pictures shown in this section are of the bottom of the left wing.

! Installing the servos

1. Insert the servo through the aileron servo mount, dropping it in from the top of the opening so that it's actually facing upside down when the wing is flipped right side up.

2. Line up the aileron with the outside edge of the wing, making sure that the control horn is facing the wing, that the beveled edge is pointing towards the ceiling, and that the whole mess is butted up against the wing.

3. Tape each aileron to the wing using clear packing tape, along the side without the bevel.

4. Using the thin music wire, z-bend one end and insert it into the correct hole of the control horn.

Correct Control Horn Hole Selection Hole closer to the control surface = more throw

Hole further from the control surface = less throw

5. Attach the micro pushrod adjuster to the servo horn, but don't attach the horn to the servo yet.

6. Run the non-bent side of the pushrod through the micro pushrod adjuster, attach the servo horn to the servo, and then screw the servo down using the screws that came with the servo.


Step 12: Installing the Motor We recommend the GWS EPS300C-D for the motor. Refer to the GWS installation instructions for more information, if necessary.

! Installing the Motor

1. Slide the gearbox through the motor mounts with the spinner facing forward. Make sure that it is FULLY seated.

2. Drill a hole through the underside of the inner cowl, through the gear box and into the motor mount.

The hole in the inner cowl should be at least 3/16" wide, so that the supplied motor retaining screw fit. Once you get through the cowl, stop with that drill bit and use a 1/16” drill bit to complete the hole through the gear box and the motor mounts.

3. Screw in the motor retaining screw.

Step 13: Attaching the Wings Next, you are going to attach the wings to the fuselage.

You will need:

• 2 4-40 wing bolts (Bagged Parts)

• 4 Metal washers (Bagged Parts)

• 2 Nylon insert locking nuts (Bagged Parts)

• 1 Motor and battery mount retaining screw (Bagged Parts)

• Battery Mount and Front Battery Retainer (Figure L)

Hole through the inner cowl

Hole through the gear box

Plane is shown upside down


! Attaching the wings

1. Position the wings so that the servos are on the underside, and then slide the fuselage attachment pieces, through the wing slots on both sides of the fuselage.

2. Make sure that all of the fuselage attachment pieces, including the upper and lower spars, are flush with both fuselage sides, and then repeat for the other wing.

3. Inside the fuselage, line up the fuselage attachment pieces, so that the holes are lined up.

4. Position the front battery retainer to the front of the fuselage attachment pieces, lining up the holes, and the screw the wings together with the following pieces, in order:

Wing Bolt ⇒ Metal Washer ⇒ Front Battery Mount Retainer ⇒ Wing ⇒ Washer ⇒ Nut

5. Slide the battery mount into the rear battery retainer located in the center of the F3

bulkhead, and then slide it back through the front battery retainer so that the tabs line up with the front battery retainer.

6. Insert the motor retaining screw into the hole, located on the battery mount. This is to make it so that the mount cannot move backward or forward from this position.

Front battery retainer

Fuselage attachment pieces properly aligned

Screws

Front Battery Retainer

Battery Mount


Step 14: Attaching the Receiver and Speed Controller We are not going to cover the receiver and speed controller (ESC) specific information, please refer to your manufacturer’s instructions for more information, if necessary.

! Attaching the Receiver

• The receiver is attached within the fuselage, forward of the batteries. Use servo tape and attach it to one of the fuselage walls. Connect the servos and ESC to the receiver, following the guides on the receiver itself.

If you want to use flaperons, you must use a computer radio and plug into two channels on the receiver. If you don't intend to use flaperons, you will need to use a Y harness, plugging in into a single channel of the receiver.

! Attaching the ESC

• The speed controller is attached within the fuselage, forward of the batteries. Use servo tape and attach it to the opposite fuselage wall as the receiver. Connect the battery to and the motor to the ESC, following the guides on the controller itself.

Step 15: Finishing the Kit Well, you're almost there…the end is in sight; just a few more steps and you can go flying, assuming the weather is cooperating.

Attaching the Tailskid This is one of those highly overlooked, but extremely important pieces if you want your backend to remain in one piece. For the Tantrum we are not using a wheel, we are instead using a tailskid.

Motor and battery mount retaining screw

Battery mount

Front battery retainer


You will need:

• Remaining piece of the 1/32" x 18" thin music wire (Wire)

! Attaching the tailskid

1. Take the remaining piece of the 1/32" x 18" music wire and bend it into the shape shown on the plans.

Needle nose pliers work pretty well to shape the wire.

2. Cut a 1/4" slit into the bottom of the fuselage, about 1/8" in from the rear along the centerline.

3. Align the tailskid so that the "V" portion of the bend aligns with the slit, and then press the skid into the fuselage.

4. Flow some thin CA over both the skid and the fuselage once it is pressed completely into place.

Attaching the Battery You need to run the double-sided Velcro strip under the battery pack, around the battery mount, and then secure it to itself snugly. This will hold it firmly to the battery mount. The kit also comes with a double-sided Velcro "seatbelt", which you will wrap around the battery and the mount.

Typically, losing your battery in mid-flight is a bad thing…a very bad thing…

Attaching the Canopy 5. Hinge the entire right side of the canopy assembly to the fuselage with a 3/4" strip of

packing tape.

6. Remove the tack from the balsa stick, and then position the stick on the left side of the fuselage, so that it's just in front of the F3 bulkhead and 5/32" below the top of the fuselage.

7. Glue the balsa stick into position with thin CA.

8. Align the magnet with the center of the balsa stick, and then glue it to the bottom side of the canopy assembly using thin CA.

9. Press the metal tack down 1/4" into the top of the balsa stick so that the magnet is aligned with the tack.

10. Apply a small drop of thin CA to the tack, where it enters the balsa stick taking care to not get any on the top of the tack.

11. Close the canopy and press it down until it's flush with the fuselage. The tack will be pushed to the correct height into the stick. Wait for the CA to set up.


Photo of the Flashback, not the Tantrum, but you get the idea.

Attaching the Landing Gear The landing gear is pressure fitted into the bottom of the fuselage.

! Attaching the landing gear

• Gently push the landing gear reinforcement piece up into the bottom of the F2 bulkhead slot. You may need to rock the gear slightly to get it into place. Once situated, the landing gear will miraculously stay in place without glue or anything else.

The good thing about using the 1/16" wire for the landing gear wire is that it's lightweight. The bad thing about using this wire is that it can just barely hold the airplane up when you use heavier batteries. With that being said, it's a good idea to brace the gear by running some of the leftover pull-pull cable across the gear about 2” up from the wheels.

Bottom of the F2 bulkhead slot

Upside down view of the landing gear

Metal tack

Magnet

Front of the fuselage


Setting the Throws You need to adjust your radio trim so that the elevator, rudder, and ailerons are all level. The throws are all the same for the Tantrum, with the low rates being 30° and the high rates being 45°. If you don't have an exponential- capable computer radio, 45° might be too much in which case you should limit the throws to 30°.

If your radio is capable of mixing, you may want to mix 50% flaps to elevator, so that when the elevator goes up, the flaps go down. This will allow the Tantrum to perform very tight loops.

Setting the Center of Gravity The Center of Gravity (CG) will affect how the airplane recovers from a nose up or nose down condition (pitch stability). With the CG too far forward, the plane will be quite stable, but require a lot of up elevator to fly level. This will result in an increased low end speed. On the other hand, too far back and the plane will be hard to control, requiring constant input to keep the plane flying straight and level. For the Tantrum, the CG should be 1/2" - 3/4" behind the rear of lower spar cap as a starting point. You can slowly move it back as you get more comfortable with the plane.

Flying For your first flight, be patient and wait for a calm day. Choose a large field where you have a smooth surface to use as a runway. Set the plane down, pointing away from you, and if everything goes well, which of course it WILL, when you apply full power, your plane will take off nicely after a slight rollout.

Documents

Tantrum Specifications8 Mountain Models Tantrum Assembling the Horizontal Stabilizer Putting the pieces together 1. Remove the pieces shown in black from the balsa sheet. To remove