Opitec Windflyer II User manual

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Windflyer II
102.056
Technical data:
Wingspan 735 mm
Length 625 mm
Wing area 9,19 dm2
Tail area 1,75 dm2
Total area 10,94 dm2
Weight 120 g
Wing loading 6,9 g/dm2
Building time as a group project, approximately 10 hours
Recommended for pupils 10 years old plus
© by B. Elsner
Please Note
The OPITEC range of projects is not intended as play
toys for young children.They are teaching aids for young
people learning the skills of Craft, Design and Technolo-
gy.These projects should only be undertaken and tested
with the guidance of a fully qualified adult.
The finished projects are not suitable to give to children
under 3 years old. Some parts can be swallowed. Dan-
ger of suffocation!

1. Product information
Article: Flying model in construction kit form
Conditions: For flying in still or very light winds
Use: With pupils aged 10 plus
2. Material information
2.1. Material: Balsa wood (Technically a tropical hardwood, soft and light)
Beech wood (Hardwood)
Pine wood (Soft wood)
Plywood (Multi layered, glued crosswise)
Working: Wood can planed, sawn or sanded
Joining: Glueing
Finish: Wood varnish (Base coat plus finish- also in spray form)
Staining (Water based - finish with clear varnish)
2.2. Material: Depron, thermoplastic
Polystyrol hard foam (PS) white
Working: Cutting with a modelling knife
Joining: DO NOT use any any glue containing solvent
Finish: No special finish is necessary
3. Tools:
Saws: Use a PuK saw from our catalogue for sawing small strips of wood and dowel
Note! Hold the work in a clamp
Cutting:: Use a modelling knife
Note! Be careful with your fingers the blade will be sharp!
Sanding: Use a block and glasspaper for all flat areas and edges
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4. Material list
Part Material Quantity Size Part no.
Body Plywood 1 8 x 80 x 300 mm 1
(Fuselage) Pine strip 1 6 x 8 x 495 mm 3
Nose sides Balsa 1 2 x 50 x 250 mm 2
Pre-cut Balsa 1 2 x 100 x 500 mm 4/12/13
Wings Abachi strips 2 8 x 10 x 374 mm 10
Balsa strips 2 5 x 15 x 374 mm 11
Pine strips 2 3 x 7 x 374 mm 9
Tissue paper 1 255 x 760 17
Fixing Rubber bands 2 60 mm dia 18
Beech dowel 2 3 dia x 150 mm 5/6
Joiners Card 1 160g/m2 14/15/16
Tail Foam 1 3 x 114 x 410 mm 7/8
Trim lead lead shot 1 34 g 20
5. Parts list for ready made components
Part No pces Material size in mm
1 Nose 1 Plywood 8 x 55 x 255
2 Nose sides 2 Balsa 2 x 48 x 95
3 Fuselage boom 1 Pine strip 6 x 8 x 495
4 Wing support 1 Balsa 2 x 20 x 125
5 Wing dowels 2 Beech dowel 3mm dia x 125
6 Fixing dowels 2 Beech dowel ca. ø 3 x 25
7 Tailplane 1 Foam 3 x 80 x 250
8 Tail fin 1 Foam 3 x 80 x 90
9 Main spar 2 Pine 3 x 7 x 374
10 Nose strip 2 Abachi 8 x 10 x 374
11 End strips 2 Balsa strip 5 x 15 x 374
12 Wing ribs 14 Balsa, pre-cut 2 x 13 x 102
13 End ribs 6 Balsa, pre-cut 2 x 13 x 102
13a Supports 4 Balsa 2 x 12 x 18
14 Joiner, upper 1 Card 45 x 125
15 Joiner,lower 1 Card 45 x 125
16 Middle, strengthener,upper 1 Card 15 x 125
17 Covering paper 1 Tissue 255 x 760
18 Rubber bands 2 Rubber 60 dia
20 Trim lead 1 Lead shot 34g
Also needed to complete this model is:
Shrinking dope 50gm
Thinner 15gm
Wood glue (Ponal express) 20 gm
Paste

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6. The layout of the balsa pre-cut ribs, sheet and Depron
62,5
4
13a 12
2
2
7
8
12
13
Pre-cut balsa ribs etc
Balsa sheet tailplane
Depron sheet
Note: Do not alter the layout due to the cutting direction!

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7. Instructions
General notes:
Keep to the drying time for the glue, otherwise you may have difficulties. Other parts can be made whilst the glue
is drying.
Use white glue, check that any glue you use does not melt the styropor / Depron foam.
Use a block and glasspaper for sanding all flat surfaces (sanding block is not included) Use an all purpose glue
to fix the sandpaper to a block.
Tick off the steps as you go along
The shortened form 'Sk' means sketch. A number in brackets (4) means part eg.4
Use mapping pins, most normal pins will bend or break under pressure!
Planning overview
7.1 Fuselage (body)
7.2 Tail plane and fin
7.3 Wings
7.4 Cover wings, spray with water and then dope
7.5 Colouring
7.6 Balancing
7.7 Flying
7.1 Fuselage
7.1.1 Assemble the building plan (Pages 15/17/19/3 pages) by cutting the plans along the broken lines and sello-
tape them together.
Note: Note the markings
7.1.2 Cut out the pattern for the nose (see plan) and using dabs of glue fix it to the 8mm plywood. Drill the 3mm
hole for the front dowel (6)
7.1.3 Carefully saw out the shape of the nose. Do not forget the 20mm and 25mm lead chambers (The openings
for the chambers will be drilled later)
7.1.4 Cut out the pattern for the nose cladding (2/plans) and trace it twice on to the balsa wood sheet, cut out the
shapes with a modelling knife.
7.1.5 Start by firstly gluing on one side of the cladding (2) and then the other
Apply the white glue in a circular motion to the nose (1). Make sure the edges that the edges are particulary
well covered. Rub the cladding on to the nose until the glue starts to 'pull' then press it into the final position
once more!
Cutting lines
Esq 1
Bead of glue

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7.1.6 Fit the boom spar (3)into the nose and glue it into position.
7.1.7 Drill the 5mm dia holes into the lead weight chambers (These holes will be covered with sellotape at a later
stage)
7.1.8 Cut two 25mm lengths from the dowel 3 dia x 150mm. Use a modelling knife (roll the dowel under the
blade) Using the plan as reference glue one dowel at the front end of the nose and the other at the end
(see plan)
Note: Do not cut both of these pieces from the same length of dowel!
7.1.9 Sand the nose and then chamfer the cladding edge at 45 degrees (See sketch)
7.1.10 Mark and cut out the wing carrier (4) as shown on page 5 and glue it in position (see diagram)
Note: Note the direction of the grain
7.1.11 Glue the side dowels (5) 3 dia x 125mm ( remainder from step 6.1.8) in position as shown in the diagram
45°
20
62,5
125
3
4
4
4
4
Esq 2

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7.2 Tailplane and Fin
7.2.1 Cut out te pattern for the tailplane (7) (Plan 8). Apply spots of glue to the rear of the pattern and lay it out on
the foam sheet 3 x 114 x 410 (See page 4). Firstly cut out the 3mm slot in the Tailplane using a steel ruler
and sharp modelling knife (7) and then the remaining contours.
7.2.2 Cut out the Fin (8) and remember the lower fixing tab.
Note: The directional (long) flap is cut after the plane has been flown
7.2.3 Sand the curves of the Fin and Tailplane to shape with a block and glasspaper.
Note: The underneath of the Fin (8) must not be sanded!
7.2.4 Ensure the Fin fits in the slot in the Tailplane.
7.2.5 Glue the Fin into the slot in the Tailplane and leave to dry
Note: The Fin must be at right angles to the Tailplane
7.2.6 Mount and glue the Fin and Taiplane on the Fuselage (3) and leave to dry!
Note: Make sure that it is mounted squarely with the Fuselage otherwise the flight pattern will be
affected!
Do NOT sand the
underneath of the
Fin (8)
This long cut for the
flap is cut after the first
flight
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8

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7.3 Wings
7.3.1 Cut out the patterns (Pages 21) and glue them together
Note: Make sure that the joins are accurate
7.3.2 Place a strip of sellotape (broken lines) over each of the ribs so that the glue from the wing does not stick to
the plans
7.3.3 Press out the ribs ( 12 /13) from the pre-stamped balsa sheet, clean them up as necessary
7.3.4 Place all the ribs( 12/13) together on the main spar (9) and sand them from front to back with a block and
glasspaper. Any irregularities can be removed on the top or bottom of the ribs can be smoothed in this way.
7.3.5 Cut out the patterns for the angled wing supports (13a) from the plan. Use the patterns on the balsa sheet
and cut them out.( See page 4)
7.3.6 Make up two sets of 3 ribs (13 / rib packet) and glue them together
Note: Use a spar to make sure that they are in line
These ribs must NOT be glued to the spar!
After these have dried for a few minutes remove them from the spar.
7.3.7 Shape the middle spar/ leading and trailing wing edges ( 9 + 10 + 11) where the meet in the centre of the
wing ( appox 11 degrees)
Note: This angle must be accurate !
45°
70
25
105
Cutting lines
Esq 3
Esq 4
9
9
13
13
13a 9

9
7.3.8 Selloptape the plans to a building board.
Note: The minimum size of building board should be approximately 10 x 150 x 400mm (Large enough
for one wing half)
7.3.9 Pin the main spar to the board
7.3.10 Lay out and glue the ribs in position along the main spar.
Press the ribs down so that they are flush with the board. ( Fix with pins) The middle ribs (A) must not be
glued.
7.3.11 Glue the angle supports (13a) against the second rib and leave to dry thoroughly.
7.3.12 Place the middle rib (A) on the end of the main wing spar and lean it against the wing angle support.
Note: This will give the V angle between the wings at a later stage
7.3.13 Glue the leading edge strip (10) in position against the ribs
7.3.14 Glue the trailing edge strip ( 11) to the ribs
Note: Leave the wings to dry overnight
7.3.15 Lightly sand the top of the ribs with a block and glasspaper
10
9
11
13a
Middle rib (A)

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7.3.16 Carefully remove the wings from the board, sand the edges ( see wing diagram)
7.3.17 Sand the angled middle wing ribs
7.3.18 Trace the patterns for the wing joiners (14/15/16) on to the 160 gm white card and cut them out using a mo-
delling knife and a steel ruler. Cut the side slot on the joiner (15)
Note: The printed shapes on the card are not accurate, cut the joiners to the plan!
7.3.19 Glue both halves of the wing to the middle joiner (14) only apply glue to the ribs and spar. The middle line
on the joiner must be just visible. Rub the joiner on the glued area and leave to dry for approximately 1/2
hour
7.3.20 Weight one half of the wings down on a building board and apply glue to the V gap in the middle
7.3.21 Raise the other wing half from the board so that the tip is 140mm high (see diagram on page 11)
Note: Leave to dry overnight
7.3.22 Glue the top wing joiner (15) in position, apply the glue to the ribs and spar, leave to dry for approx 3 hours
7.3.23 Glue the middle joiner/strengthener (16) in position
76.3.24 Clean up any excess card
15 20 20 20 20 20 10
125
454515
15
14
16
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7.4 Covering the wings, water shrinking and doping
7.4.1 Cut the tissue paper through the middle with a razor blade (approx 255 x 380mm)
7.4 2 Coat the leading/ trailing edges/ ribs on the underside of the wing with wallpaper paste or Glutofix
7.4.3 Line up the paper with the wing edge and gently stretch it over the wing smoothing out any wrinkles as you
go.
7.4.4 Coat the top of the wing,leading edge etc with paste
7.4.5 Hold the wing in the air, turn it slowly so that the covering paper lays over the top of the wing.
Note: Try this stage before aplying the glue !
Press the covering down with your fingers (If there are points where the paste is dry, more paste can be
added with a brush, it will soak through the surface of the tissue)
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114,3
15
17
16
140

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7.3.6 Using the same technique cover the second wing half (Steps 6,3.2 to 6.3.5) any excess paper can be cut off
once the wings are dry, approx 1 hour
7.3.7 Spray the wings with a light mist of water (use a plant spray) from a distance of 500mm. The paper will sag
slightly and then dry taut. Lay the wing on its trailing edge so that an even coating of water can be achie-
ved, this will stop the wings from warping.
7.3.8 Once dry,the wing can be coated with a thinned 1:1 mixture of shrinking dope and thinners and placed on
the trailing edge to dry
7.3.9 Coat the wings once more with UNTHINNED dope. All the wood parts can be given two coats of unthinned
dope. Sand all the doped surfaces between coats..
Note!!!
Do not coat any Depron parts with dope as this can cause it to melt!
7.5 Decorating
7.5.1 The decorative 'Opitec' strips can be stuck on the wings and fin
7.5.2 Fill in the label (see plan) and glue it to the right hand side of fuslage with an all purpose glue
Name labels

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7.6 Balancing
7.6.1 Side balance
Lay the wings on a table top and try to balance them. They should always fall to different sides. If this does
not happen add a little weight to the lighter wing tip. Glue small pieces of lead to the wing tip.
7.6.2 Fix the wings to the fuselage with a diagonally stretched rubber band.
7.6.3 Finding the centre of gravity
Hold the the plane with two fingers placed under the wing by the main spar or place it on the handles of an
open pair of pliers set in a vice
Add lead shot to the weight chamber (starting at the front chamber) until the model lies flat with its nose
slightly downward.
Your model is now ready to fly
7.7 Flying
7.7.1 The Wind Flyer 2 is designed for flying only in light or no wind conditions only. For your first flight choose an
absolutely still day and a lightly sloping flying field
7.7.2 If you fly in any wind always launch the model into the wind.
Hold the model between two fingers just behind the tow hook and launch it forward into the wind. This will
need some practice!
Note: Of course you must have checked the balance first
7.7.3 If the model 'pumps up and down' in flight add a 15 x 25mm card strip under the trailing edge of the wing.(
The angle of attack is mad e smaller)
Keep repeating this stage until a smooth flight path is achieved
7.7.4 If the model dives add card strips under the leading edge of the wing ( the angle of attack is made larger)
Repeat this step until a smooth flight path is achieved
7.7.5 If the model flies in a curve a flap needs to be to cut in the wing on the side that the flight curves
- Make an 8mm deep cut in the trailing edge of the wing, 25mm and 105mm from the wing tip. Then cut a
2mm deep line between them. (See wing diagram)
Note: do not cut the lengthways line all the way through!
- Now bend this flap carefully down until the model flies straight
- Once the flight pattern is correct this flap can be fixed in position with a few spots of glue.
7.7.6 If the model flies into a curve without banking then a rudder flap needs to be cut on the tail fin
- When the fin was made, there was a place for an upper and lower cut to make the rudder
Now make a 1mm connecting cut between these cuts on the fin and bend the flap in the required direction
until the flight path straightens.
Note: Only score this connecting line do not cut all the way through the fin.
- Once you are satisfied the rudder can be fixed with a few spots of glue.
7.7.7 For a towline start you need 25-50 metres of line.
If you have never launched a model with a towline it is better if you find someone with experience who will,
glad to help you.
We wish you lots of fun with your Wind Flyer 2

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Plan / patterns Scale 1:1
1
2
3
11
9
12
5
4
10
6
6
6

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Plan / patterns
Scale 1 : 1
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Pattern for the nose (1)
Wind Flyer 2
Wind Flyer 2
Hochstarthaken

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Plan / pattern
Scale 1 : 1
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Pattern, tailplane
Pattern, nose, side clad- ding
Pattern, tail fin
Pattern wing rood angle, joiner
8
7

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