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Saturday, 2 May 2020

Slope TRACER Build

Slope Tracer Build Documentation 


This article has instructions both for the Slope Tracer and the Foam-board Spitfire.

Slope Tracer Build

The Slope Tracer is a great fun aerobatic slope plane. It can fly is a large range of wind conditions and with its EPP fuselage, it can take the rough and tumble.

Wingspan: 1300mm
Weight: 700-900 grams
Wing Loading: 11-14 oz/sqft  32-41 sq/dm
Airfoil: SD6060 mod tip
3 channel two ailerons and one Elevator (no rudder)
EPP Fuselage
Foam core balsa skin wings
Slope Soarer for Intermediate/Advanced  RC Pilots 
Suitable for light to strong winds (10knt-30knts)
Ballast can be adjusted
CoG 64mm from leading-edge

Supplied Tracer Parts

EPP CNC Fuselage
One Set White Foam Wing Cores
One set of Core Flute Tail and Fin


*1.5mm Balsa Sheeting for wing 2x (1220x150x1.5)
* Balsa Aileron Stock 
* Balsa Leading Edge stock
* 3mmx1mmx750mm carbon strip for fuselage
* Titebond   Original   *3m Super 77 Spray Adhesive
* 5 min Epoxy  
* Controls horns + Linkages 
* Masking tape   
*1600 Mah Nimh 4-5 cell battery (4.8/6v)
*Iron-on covering for both wings and fuselage
* 3 Mini Servo’s 2.6kg  *Servo Extension wires
* 3mm bamboo stick from tailplane, 1.3mm piano wire for canopy

Tools Required:

Sharp Knife, Sandpaper, Covering Iron

Step One: Prepare Fuselage

Cut out access bays for Nose Weight, Battery, Cockpit, Servo Wires, Stiffening Strips and Rear Servo Bay

Use a sharp box cutter, a Dremel with a burr or a hot soldering iron to cut out access for the 90-gram nose weight (8mm each side), battery compartment (8mm each side), and cockpit(15mm each side). These are cut equal amounts on both the left and right-hand EPP fuselage sides. You can just use one side to cut access for wires and the rear elevator servo. (Wires holes about 4mm deep)
Note: You will need to find about 90 grams of lead to fit in the front cavity to ensure the CoG is in the ballpark.  We use a ladle and a blowtorch to melt lead into a useful shape, or you can just cut-up the lead sheet to suit. (25mmx 20mm x17mm thick).  Cut the slot in the fuselage for the bottom and top stiffening 3mm x 1mm carbon strip. The carbon strip can be glued in with CA. Make sure the flat side of the fuselage is flat on the bench while gluing to avoid a twist in the fuselage.

Step Two: Prepare wing

You need to make access cavities for the wing servo wires. This is best done using a heated brass tube. Refer to the wing diagram below for placement. The wires will exit about the middle of the topside of the wing. The servo holes are approx. 55mm from the Leading Edge and 100mm depth on each side.

Prepare 1.5mm balsa skins, best to cut balsa proud with about 5mm overlap over the leading and trailing edges of the foam cores.

1220 mm x 150 mm balsa sheets are ideal as the length is about right with 30mm tip blocks

Join the left and right-hand foam cores and bottom jackets together with 3m Super 77 or 5-minute epoxy.

Use bottom foam jackets to reference cores… the wing should be flat on top.
Use your favourite method to attach skins  Make sure the glues are white foam friendly) ( ie Epoxy/ 3m77/ Carpet Contact/ Titebond etc. 

It's a  good idea to put the cores back in the jackets and apply some weights to the top. This should help keep the wings straight and true.

Step Three: Attaching leading and false trailing edges.

Glue the leading edge strip and a 1.5mm balsa cap on the trailing edge, use masking tape to hold in position until dry. ( Titebond or epoxy)

Step Four: Shaping Leading Edge and sanding trailing edge.

The leading edge needs to planed or sanded to shape, as a guideline the Leading Edge tapers from about 10mm and the root to 6mm at the tip. The profile gauges supplied should be used to check the correct shape.  Sand false trailing edge to the balsa skins. Glue tip blocks in place to give a wingspan of 1300mm. Shape tips.

Step Five: Shape Ailerons

The ailerons should be about 50mm at the root(220mm) and 28mm at the tip(120mm)
You can use 50mm aileron stock or use a suitable balsa block to shape. The Ailerons start 60mm out from the wing center. You can lightly tack or tape the stock to the false trailing edge to help with the shaping. Permanently glue the 120mm centerpiece.

Step Six: Fitting the wing servo's (mini servos such as EMAX ES09MD, TRGY9018mg, many of the slim wing servos are also a good choice for the wings)

Start by cutting out the servo bays, these are 45mm squares at 90 deg to the aileron hinge line. They are positioned 92mm out from the center line and 58mm from the false trailing edge. Fit the servo frame about 2mm below the balsa to ensure the cover is flush with the top. Pick out the foam within the servo frame, you should be able to see the servo wire conduit cut earlier.
Make a penetration on top of the wings to exit servo wires.

Step Seven: Covering the Wing

This is where you need to decide on colours and what film. We find dark colours stand out and it's a good idea to have a contrast between the top and bottom.  The covering can also act as a hinge on the top and bottom.

Step Eight: Attach Wing, Fin and Tailplane

Score a line on the bottom of the coreflute tailplane 30mm back for the elevator. Use the top of the coreflute as a hinge.
Use epoxy to glue both the tailplane first then the fin, it's important to ensure the tailplane is to parallel with the wing and the fin is 90 deg. You should also check the distance from the wingtip to the tailplane tip to ensure both sides are the same. It's a good idea to insert a carbon rod (3mm) or bamboo stick through the tailplane about midpoint to help with stiffness.

You are now ready to glue the wing in position, you can use 5 min epoxy to give yourself some working time to ensure the wing is correctly positioned before the glue sets.  First, apply epoxy to the midsection only, position, and let set. The second step is to create a fillet where the wing meets the fuselage. This can be epoxy or silicon, use an icy-pole stick to create the fillet top and bottom.

Step Nine: Fitting the canopy

Trim the canopy to suit, we like painting the bottom of the canopy to match the fuselage profile, we mark the profile then using masking tape to cover the top of the canopy to profile line and paint the bottom.  We use a wire through the front of the fuselage to hold the canopy.

The finished Slope Tracer ready for balancing. (64mm from Leading Edge)

Step Ten: Control throws and flying

We recommend dual rates on all control surfaces. The Ailerons need some differential to give the best turning and roll performance, as guideline aileron, 7mm up and5mm down. The Elevator needs 5mm up and down. These are good starting points, please tune as required.

Check the CoG 64mm back from the leading-edge, check the lateral balance across the plane, charge the battery and go flying....


Andy and Richard

Sunday, 24 March 2019

Foamboard Spitfire Build

AREA17 Foam-board Spitfire (Night Flyer Addition)
Based on The FliteTest Spitfire
Find us on Facebook   AREA17

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

Hardware Required to Finish
* Motor Brushless 2826 1400kv 8x6 prop (looking for 180-200 watts)
* 1500-2200 mah 3s lipo
* 25-30 amp ESC
* 3 Mini servos or 4 with an optional rudder
* CoG on Wing Spar line (65mm from leading edge)
* 4 Extension leads
* TX and min 4 Ch RX
* Control linkages and horns
** Optional carbon blade spar reinforcement (10mm x 0.5mm)

Parts Supplied
* Three  Laser-Cut Foam Board Sheets
* Canopy
* Ply Motor and Battery Box

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

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

*Next is the fuselage former's
 *Use a piece of scrap to separate fuselage sides

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

*Next Tailplane and Rudder
 45deg chamfer on tailplane side
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 both 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 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.

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 hole(s) for the rear bamboo stick. This is done with a long drill or by marking and drilling from each side. The location for the rear bamboo stick should about 150mm from the front of the ply box or about 170mm from the front of the fuselage. The stick should penetrate near the top of the box to ensure the battery is not fouled.
The Battery can be placed inside the pod, or for quick changing can be Velcro-ed on the underside.