Foamboard Spitfire Build

AREA17 Foam-board Spitfire (Night Flyer Addition)

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General notes:

• Steamers are typically attached to the fin with sticky tape.
• The 4th channel rudder is optional and not required, just bank and yank.
• The optional carbon wing spar blade is not needed with the standard 3s setup.
• The ME109 version uses the same construction method.
• Before painting scrub the surfaces with scotch brite to help key the paint.
• 3d printed exhausts and pilots STL files can be found on Thingiverse.com
• You can use velcro on the underside of the motor pod to secure the 3s battery

CoG on Wing Spar (65mm from leading edge)

Tools Required
* Sharp Blade                * Clear tape
* Ball Point Pen             * Optional 10mm x 0.5mm carbon blade
* Hot Glue Gun             * Icy pole sticks

* Z Bender's for linkages * Set Square

Hardware Required to Finish
* Motor Brushless 4mm shaft 2836 around 1400/1500kv 8x6 CCW prop (looking for 180-230 watts)

* 4 x3mmx12mm screws and nuts for mounting the motor.

* 4mm bamboo skewers to hold motor pod
* 1800-2200 mah 3s lipo min 40c Not suitable for 4s without the carbon wing blade.....
* 40 amp 3s ESC with BEC
* 3 Mini servos 1.6kg to about 2.6kg or 4 with an optional rudder eg MG90s/HXT900/EMAX ES08A/ 

* 3x300mm Extension leads or 4 with the rudder option.
* TX and min 4 Ch RX

* Velcro for battery
* Paper ribbon attached to fin for combat

* Optional carbon blade wing spar reinforcement if on 4s over 250 watts (10mm x 0.5mm)

* 3 Control linkages 1.6mm piano wire, horns and pushrod stoppers, 4 if rudder is used.

 What you get for $45 plus delivery

* Three 5mm  Laser-Cut Foam Board Sheets

* Clear Canopy

* 3mm Ply Motor and Battery Box

Please note the brown paper backing is no longer available. 

Type of operations
* Crease Line
   o Use a ballpoint pen to create a groove allowing a bend, Typically used for turtle decks
* Cut Lines
  o Use Blade if necessary to out exterior shapes
* Fold Lines
  o Use a blade to cut through the foam only not the paper backing
* Chamfer Lines 45 deg
  o Leading edge 45 deg both sides to allow the leading edge to fold back
  o Ailerons, Rudder, Elevator 45 deg on one side

Getting Started

Fuselage
Note in some cases we have removed the backing on one side as this will be a night flyer, a standard flyer you leave the paper on.....

Start with the back Turtle deck:
* run a ballpoint pen down the crease lines to allow for folding. Note: by controlling the angle of the pen you can increase/decrease the groove width. You need a wide "V" shape to enable a smooth folded curve.

* peel the foam off the outside edges, this should just leave the paper. This paper strip acts as a glue tab when gluing the turtle deck to the fuselage. 

Now the front Turtle Deck
*as above run a ballpoint pen down the crease lines to allow for an even fold.

* peel the foam off the outside edges, this should just leave a paper tab.

On to the Fuselage
*pick out the foam to create the fold lines and tabs. We find by removing the backing paper first makes the removal of the foam strip easier. We made a handy machine to remove the strip but it is easy remove the strip by bending and prizing out with your fingers or a tapered icy pole stick.

Note leave the wing section cutouts in place, they get removed later

Now we use the power pod as a guide to hot glue the fuselage sides, Note do not glue the power pod in... note the latest pod has a doubler on the firewall.

*Next is the fuselage former's

 *Use a piece of scrap to separate fuselage sides

Glue the turtle deck formers in place, note number 1 goes on the front (without tab)

Note the led lights on this model mounted inside...

*Next Tailplane and Rudder

 45deg chamfer on tailplane side, this can be done with a sharp knife or flat sanding board

Use clear tape as a live hinge
The Rudder control surface is optional, if you elect to use the rudder use the same method to create a control surface.

*Its time for the wings
First up, chamfer the leading edge about 60 deg on the inside edges, keep testing making sure it will fold back on its self without pressure. Use clear tape on the outward side to keep the parts together. * Note you do need to remove a lot of foam to get it to fold back with pinching.

Use a pen to create the two crease lines, followed by a 45deg chamfer on the ailerons, the Ailerons need to operate up and down without pressure, use clear tape as a live hinge on the top.

Prepare the two wing spars,  you can simply fold and hot glue. (Optional if you intend 4s hot dogging a flat carbon blade (10mm x0.5mm) sandwiched between will ensure high G maneuvers are safe.) Note the standard foam-board spar is fine for general aerobatics on 3s.

Glue the spars into the wings making sure they align when the wings are mated.

The false trailing edge piece is then hot glued in place, using a pen squash the trailing edge down creating a "V" shape to give the right angle when the wing is folded back.

**Special note: When you are happy the wing folds back on itself without a lot of pressure, we can firstly put hot glue on the top of the spar and fold back aligning the trailing edges. Let the hot glue cool and then run a bead along the trailing edge. Fold over and hold in place until set.

The wing servos can now be mounted with hot glue, mouse the servo leads down the wing exiting just in front of the spar, cut a small relief to exit the wings on the top.

Special note: glue the two sides together allowing for 60-70mm dihedral in total, ie 30-35mm each side. This picture shows the assembled with one wing flat on the bench and the other showing the total dihedral on 70mm

 Use hot glue and clear tape on the outside to join the two wings halves.

The next step is to glue the Wing and Tailplane/Fin in place, turtle decks happen when all flying surfaces are aligned and glued. Note: take your time and make sure all the flying surfaces are aligned before gluing. You can put blocks under the wing to help align the tailplane, use a set square to get the fin and tailplane at 90 deg.

Next up is the rear Turtle deck
Start by putting a dob of glue on the peak of the rear formers, we glue the middle first and let dry, then glue the sides.

Now the front Turtle deck
Glue one side of the back section, let dry then glue the other backside. Repeat for the front section

Fitting the canopy

Trim the back turtle deck flush with the former

Trim the front turtle deck at a slight angle

Make a canopy base out of scrap, glue in place

Add pilot if required

Hot Glue canopy onto the base, back former, and front turtle deck

The motor pod is held in via a 3mm ply plate/tongue at the front and a removable bamboo stick at the rear. You then need the hold the motor/battery box in place with the tongue engaged and drill a 4mm hole(s) for the rear bamboo stick.  The location is a laser hole about 150mm back from the front of the Pod. The stick should penetrate near the top of the box to ensure the battery is not fouled. The round ply washes found on the tongue of the motor pod are glued to the sides where the  bamboo skewers go through for reinforcement.

The Battery can be placed inside the pod, or for quick changing can be Velcro-ed on the underside.

Tips:

Under-hand launches holding the top of the fuselage are the safest method. This way the model is released in and upward direction.... about 2/3 power is about right.

The CoG is on the front of the wing spar. 63-65mm from leading edge.

Some aileron differential is required, suggested starting percentage is around 30%.

Control surface throws should be on about 5/6mm.