cad2cnc Tango 3.15 User manual

Tango 3.15
Dear Model Making Friend,
Congratulations on your purchase of the Tango. This model been developed with state-of-the-art computer
aided design, and manufactured using C C milled and laser cut parts to create a kit that builds into a strong and
accurate structure. Even a less experienced modeler can successfully assemble this great model in a reasonably
short time.
The assembly mainly uses thin cyano but some parts ie the Wing plug, motor mount etc should be glued with
epoxy resin.
The Tango is an extremely good-natured glider with very good flying performance and, with its large spoiler,
can be landed very slowly and precisely.
Contents of the kit
The kit includes all parts for the structure of the aircraft.
Other items required are:
• RC system with at least 6 channels (some users recommend a higher channel count so that the two flaps can be
set up individually.
• Complete electric drive: motor, ESC, folding air screw with 40mm spinner.
• Covering (e.g. Oracover)
• Cyano, Epoxy resin, White glue
Recommended drive train:
The motor should not exceed 30 mm diameter, it must have a front mount and should weigh between 1200 and
1700g.
Some possible examples are:
• Hacker A20 EVO with 3S LiPo
• Staufenbiel X-Max X28L outrunner.
• Staufenbiel DYMO D MASTER HQ 2838 or 2832.
• Poly Tec 400 F5J Motor 2-3S LiPo
Controllers and air screw according to Manufacturer's recommendations.
Recommendation Servos:
4 off KST DS135MG wing, 4 off servo mount frame.
2 off KST DS145MG elevator and rudder.
Recommended control throws (measured at the end of the control surface)
Elevator: +/- 12 mm / Landing mode - 1-3 mm, must be added
Rudder: +/- 30 mm
Aileron: + 15 / - 10 mm
Aileron offsets: Landing +8mm/Speed +2mm/Thermal position -1mm
Flaps airbrakes: Landing -90° /Speed Position + 2 mm /Thermal position -1.5 mm
Technical data
Wingspan: 3150 mm
Length: 1265mm
Weight: 1550g
Wing loading 24.5 g/dm2
Aerofoil: HQ 30/11-10
Have fun building!

Tango 3.15
Tips and tricks
A few tips for building the model. Please read carefully.
During construction, it is recommended to look back at these tips from time to time.
Due to the plug-in system, it is difficult to make
mistakes in assembly. We also recommend that the
joints be made initially with only 1-2 drops of thin
liquid cyano. Then check everything is correctly
aligned and only after that should the component be
securely glued. Since the thin cyano soaks through
the joint it can penetrate to the work surface and glue
everything down, It is helpful to work on a surface
that resists glue penetration and can be detached
from the components. A layer of greaseproof paper
or florist’s film is helpful here. You could also use
cling film, this does stick to cyano but can be carefully
stripped off afterward.
Apply clear tape to the outside of the joints then glue
from the inside. The tape may then be quickly
removed leaving a secure joint.
The interlocking structural design produces an
extremely stable cell, which provides the fuselage
with excellent rigidity. As a result, the fuselage can
be built up without distortion.
The wing fixing is by dowels passing into the fuselage
former anc nylon bolts.
Note: The fuselage longerons are only inserted
when the side walls are assembled, being inserted
from the rear. Therefore, when gluing the fuselage
sides be careful not to allow glue to block the
longeron notches.
In order to strengthen the wing root, a 0.4mm
plywood reinforcement is used. To clear the wing
mounting plate in the fuselage the wing surface must
be sanded back in the area of the mounting screws
otherwise a snug fitting of the wing to fuselage will
not result.

Tango 3.15
Attention: The fuselage sides are different lengths.
This is to allow for the side thrust. You must assemble
the fuselage with the shorter side on the right.
The center of gravity is 80mm from the wing leading
edge. The holes in the fuselage side serve as a
balancing aid.
With the center of gravity balance included in the kit
it can be easily checked and adjusted.
The model should sit in a slightly nose down attitude
when supported by the balance rod passed through
the balance and the holes in the fuselage.
The last picture shows the dihedral support for the
outer wing panel.
To allow the thin liquid cyano bottle to dispence
precise quantities of glue insert a hypodermic needle
into the nozzle and secure with tape. Needles should
be availible at your local pharmacy. Should the
needle become clogged you can carefully burn out
the blockage using a cigarette lighter.
Caution: Please refer to the manufacturer's
safety instructions.
We recommend ORACOVER for the covering
of the flying surfaces. For details of the best
methods for applying this covering please refer
to the Oracover website.
(http: www.oracover.de )
Here you can check out the range of colours.

Tango 3.15
Control hinges may be made using adhesive
tape (normal scotch Tape) by applying Inside
and outside you get a good hinge. It is also
possible to use the covering film to create the
hinge. Check the internet for the techniques
for doing this.
Another alternative is to cross the tape.
Use 2 narrow strips of tape with 3mm
overlapped and the adhesive areas Stuck
together. Then use pairs of the tape strips
crossed over and under as shown. Use
several pairs on each control surface evenly
spaced over the span. This is a little more
elaborate but gives a Longer life.
Warranty and Liability
Should a part have been damaged during delivery we will of course replace it.
All parts can also be reordered. Describe the required part briefly or take a photo to make an order.
Unfortunately we cannot give a guarantee on the aircraft since manufacturers and sellers have no
influence on the proper construction and operation of the models, any liability is excluded.

Tango 3.15
Standard tail
It takes only about 15 -20 minutes to assemble the tail
surfaces.
Dry assemble the wooden parts on your building
board and then glue with cyano. As cyano can
penetrate through the whole joint you need to
ensure that the component does not stick to your
building board – see note above.
The rudder has a Reinforcement of 0.4 mm plywood
glued to its lower area.
Note: Position the plywood over the rudder and fix
with a small drop of cyano in the center cutout.
Then lift the plywood at the edges Insert glue and
press it back into position.
Before fitting the edges of the plywood may be
beveled on the outside surface to produce a feather
edge as this will blend in better with the surface of the
rudder when covered.
For better aerodynamics, the leading edge of the fin is
rounded. The trailing edges of the rudder and elevator
are tapered evenly on both sides leaving about 1mm
thickness at the TE which is then rounded off.
The elevator and rudder hinge lines are sanded
to 35 ° to allow clearance for the surfaces to move.
The surfaces of the parts are finished with a fine
Abrasive paper (220 grit or finer) with the help of
a sanding block to give s smooth surface.
The drawing shows the section required with the
leading edge rounded and the trailing edge tapered.
The blue areas need to be sanded away.
The drawing also shows the 35 ° angle at the hinge
line. The hinge tape should be applied after covering
and assembly to the fuselage boom.

Tango 3.15
Installation of the tail surfaces onto the carbon tube:
First, glue the two plywood strips on fin with a
drop of cyano.
Note: The pictures show Extensions to the
plywood reinforcing piece that extend into the
carbon tube. The kit is supplied with the
reinforcing pieces cut without these sections,
so it may be necessary to add these pieces
separately.
When assembling the tail surfaces.
Pack up the fin by 4mm whilst gluing
to the fuselage boom.
(Use the fuselage hatch cover)
Now you are introducing the tail plane. it
Should not be too tight in the slot. If it is,
then ease the fin slot a little. The tail plane
must be glued in at right angles to the fin
and the fuselage boom.
Important: Before joining the fin and
tail plane to the carbon tube, carefully
remove the film from the joining areas
with a soldering iron or knife.

Tango 3.15
Fuselage structure
Glue the formers 2 and 3 and the servo
mount at 90 ° with small drops of cyano.
Don't put on the base!
The kit provides a plywood angle gauge,
with the angles needed for construction.
Note: The fuselage side is labelled
on the inside.
Tack glue the laser cut battery
support and former 1 to the assembly
but do not glue the battery tray to the
fuselage side.
Press the spine nuts into the
underside wing support plate and fix
onto the fuselage side. Ensure the nuts
face downwards, see picture.
For added security the nuts
should be glued in place with
Epoxy Resin.
Add the second fuselage side.

Tango 3.15
Carefully clamp the fuselage sides to the internal
structure and securely glue. For a firm joint
Leave to dry for longer than usual (2-3 min).
(Instead of clamps a large rubber band may do.)
Glue the 3-piece fuselage bottom together on
a flat board.
The motor mount is fitted in the locating holes
in the sides. Assemble and clamp together.
Should one side be stiffer than the other
resulting in an unequal curvature, then brush
the straighter side with warm water on its
outside in order to achieve an equal degree of
bend. Glue with Cyano and leave for 2-3 min
to dry. You may use the fuselage floor to
correctly align the engine mount but do not fix
it at this stage. Note that the motor mount is
not at right angles to the fuselage but is angled
to the right in order to give the correct
right-thrust to the motor.
NOTE: The additional notches in the motor mount
(shown in red on the picture) must be positioned
on the lower part off the fuselage mounting tabs.
These will later take the 3x2 mm fuselage longerons.
The 4x4 mm balsa strips are now inserted
into the notches in the bottom edges of the
fuselage, and when properly inserted the joints
are soaked with thin cyano. They may then be
sanded flush with the fuselage sides.
Similarly, fit stringers to the fuselage top.

Tango 3.15
When inserting the 2x5 mm pine strips,
it easy to break the formers due to the
square ends of the strips. It is therefore a
good idea to slightly taper the ends with
sandpaper before inserting them. They
should then be inserted from former 4
through the whole length of the fuselage
until they pass through the motor mount
and then be glued in position. Due to the
curve of the sides it may be useful to use
a few clamps to hold them in place while
gluing.
Note: The edges must not protrude above
the sides in the area of the wing seats.
Zuspitzen
Add the fuselage bottom, using Cyano.
Reinforce the joints between the motor mount and
the sides and bottom with 5min epoxy. Do not get
Epoxy on the rear face of the motor mount where
the motor will fit as this needs to be perfectly smooth
to allow the motor to align properly.
Fit the fuselage top. (use epoxy for the motor
mount joint).
Taper the end of the fuselage top to a
thickness of about 1mm and blend in with the
fuselage sides. Also trim the balsa stringers to match
the sides.
<<
Add the reinforcing former 2a being careful to
accurately align the 4 mm holes.
Now while the interior of the fuselage is still
accessible reinforce all the joints with thin cyano.

Tango 3.15
Now break out the sanding block
and sand down the triangular sections at the
nose end to meet the edges of the motor mount.
Do not remove any material from the mount
Itself.
The 6mm balsa pieces can now be glued in
place. Before adding the last piece reinforce all
the motor mount joints with epoxy. Be careful not
to get epoxy on the inside surface of the mount
where the motor will fit.
Once the glue is firmly set then sand down the
overhanging pieces of the sides and blocks flush
with the front of the motor mount and epoxy the
nose ring in position and sand the outside of the
nose to a pleasing contour.
Sand the rear end flush with former 4.
To attach the rear block. First thread the carbon
tube through the block. Next apply white glue to
the rear former. Fit the block in position using
the carbon tube through the hole in the rear
former to achieve a perfect fit. Before the white
glue sets, tack the block in position with a few
drops of cyano applied to the outside edge and
then remove the carbon tube and clean its
outside of any white glue residues. The
fuselage should now be put aside to allow the
white glue to firmly set.
ATTENTION: Do not glue the tube in yet as this
must be done later!

Tango 3.15
Add the doublers to the fuselage hatch, the positions
are engraved on the hatch inside.
The plastic tube is supplied full length and should be
cut after assembly. Slide the wire catch into the tube
and epoxy the tube in position taking care that the
bent portion of the wire protrudes through the slot in
the hatch.
ATTENTION: Ensure that no glue comes into
contact with the wire!
Once the glue is set cut off the tube flush with
the end of the hatch, save the cut piece and fit into
the fuselage in line with the hatch pin.
The cut off piece of the lid is glued inside the
fuselage in line with the position of the metal pin once
the hatch is in position.
The whole fuselage is now sandpapered to a
nice, rounded shape.
It may help to temporarily mount the motor in
order to blend in the fuselage curvature and make a
nice shape. Be careful not to damage the spinner
whilst working on the fuselage.
Shape the rear block to a smooth shape.

Tango 3.15
Glue the two control cable outers into the
small circular spacers They should be
only lightly glued to avoid problems when
installing the control system into the tail
boom. Note the positions of the spacers
shown on the photo.
The cables are fed into the tail boom
from the front. In order to ensure that
the controls exit on both sides of the
fin the wires are fed in from the tail
end and then inserted into the outer
tubes as they are glued and fed into
the tail boom from the front (Use epoxy).
The outers should not appear outside
the boom at the rear end and should
show about 1cm sticking out from
the front end.
Insert the tail boom into the fuselage so that it
passes through former #3 by about 1-3mm.
Place a straightedge across the wing seat and check
by eye that the tail plane is exactly parallel to it.
Once everything is lined up, tack the boom in place
with a little cyano at former #3. Once secure hold the
fuselage nose down and drizzle cyano around former
3 to secure.
When the glue sets add glue from the other side, and
also around the tail block.
Note: The fuselage may now be covered with iron-on
film in a colour of your choice
Mounting the tail boom

Tango 3.15
It is important that the elevator is hinged
in place first as it would be impossible to fit it
after the rudder is hinged.
Note: Refer to the earlier notes on
hinging methods.
Note: that the photos show the control
attached to the control horns using the screw
connectors.

Tango 3.15
Wing
The photos show the construction of the right wing.
The left wing is built up as a mirror image. The Plan is
transparent and may be used for both panels by
turning it over and using the other side.
IMPORTANT: The supporting blocks on the ribs
are only provided on the end ribs, when the
wing construction is completely finished they
may be removed before covering.
The perforated servo mount must be Inserted between
the ribs before they are glued into position.
IMPORTANT: The dimensions of the plan can vary
depending on humidity etc. As a result, small
differences to the rib spacing may result. This is not
critical to the wing construction. The only important
thing is that the left and right wings are built exactly the
same. Comb type rib placing jigs are provided in the kit
and you may choose to build to the jigs or the plan
whichever you prefer. We recommend using the jigs.
NOTE: The carbon tube spars are
provided cut to length with only 1mm extra.
Therefore, the spars should be positioned
precisely over their positions on the plan
needing only a very light tidying up after
construction. Sand the surface of the spars
in the areas to be glued.
The ribs are threaded onto the spars in their
correct positions according to their numbers
supported from the building board on their jig
tabs and positioned vertically (this may be
done using the rib position jigs provided).
The structure should be weighted down
(eg. With a steel straightedge) to keep it true
whilst gluing.
NOTE: The ribs are only permanently
fixed to the spar tubes (using 2 hour epoxy
resin diluted with methanol) after the trailing
edge is fitted.
ATTENTION: The first and last rib may not
be aligned using the (comb) jig they must
be set using the provided angle templates
to take account of the dihedral. (The plan
indicates which angle to use on each end
rib.)

Tango 3.15
NOTE: Don't forget to include the Servo
mount and the plate for the fuselage
locating dowels whilst assembling
the ribs
Add the two 4x2mm strips at the trailing
edge for the support of the triangular flap
support strip.
The triangular flap support strip is
fitted against the 4 x 2mm strips
flush with the bottom of the ribs and
with the pointed side uppermost
(See diagram).
Glue in place
the 3 mm carbon leading edge tube.
Turn the plan over and repeat the procedure
for the other inner wing section.
Mid Span Section
1. Fit all ribs on the 8 mm carbon spar
2. adjust the ribs over the plan using the
(comb) jigs.
3. Carefully slide in the 12mm carbon spar.
4. Add the servo mount.
5. Continue as per the inner wing panel.
Note: Angle the first and last rib with the
angle jig as before.
Add the leading edge (3 mm tube) and glue.

Tango 3.15
The 4x2mm pine strips are a glued in place
followed by the triangular aileron spar.
contrary to the inner wing, this is fixed with
the acute angle downward and the top edge
flush with the ribs (see picture).
The aileron will be hinged to the top corner
of this spar.
Turn the plan and repeat as before for the
second mid-span panel.
Tip section.
Use the shorter 6mm carbon tube.
Again, angle the first rib using the dihedral
jig.
Add the remaining ribs including the last
with the (comb) jig. Also add the
reinforcement between the last two ribs
and glue.
Add the leading edge (3 mm tube) and
glue.
Sand the spars and leading edge flush with
the end then add The tip block, this is
made from the triangular block and is
shaped to match the tip rib. Use sticky
tape to protect the ribs whilst performing
the shaping operations.
The wing joining tubes are threaded into
the root ribs and fixed with a generous
fillet of epoxy. Be sure to epoxy them to the
spars as well as the ribs.
NOTE: At this point the German
instructions mention the use of a brass tube.
I can’t find any other reference to this, but I
believe it may be used if a plug-in tip is used
instead of the permanently attached version
shown.
Fit the triangular trailing edge piece and
glue.

Tango 3.15
At this point don’t forget to reinforce all the balsa- to-
carbon joints with diluted epoxy if you haven’t already
done so.
Take the glass fiber spar connector for the 12 mm
spar and fit the plywood part as per plan. The
plywood serves as a centering for the connector.
Adjust the two connectors carefully to ensure that
they fit perfectly into the spars or ribs.
It should be enough to round the corners slightly.
Check the fit of outer wing and that the ribs line up
perfectly at the joint.
First fit the spar connectors in the mid wing panel and
leave to set. Then put the outer wing in place and
glue. Use epoxy for all these joints.
The mid wing panel uses s similar technique to the
outer section. The mid wing panel is already
attached to the smaller outer wing.
Glue together the fiberglass joiners and the
plywood parts.
The smaller part on the right sits at an angle to
allow for the angle of the spar in the mid wing
panel.
Insert and glue the connectors into the spars in
the inner section.
Let it dry before continuing otherwise, the
connector will be pushed into the tube.

Tango 3.15
Fit the lower sheeting for the inner wing
panel (with the cutout for the multiplex plug)
as in the photo. At this point there is also a
3mm balsa Reinforcement to the thin
plywood. Reinforce the joint with the leading
edge with epoxy and chopped strand fibre filler.
Round one end of the 4 mm carbon wing
locating pin (for easier insertion into the fuselage
when assembling the model)
Glue in with epoxy, flush with the mounting plate.
Decide whether to install the servo wiring now or
later.
Glue on the upper sheeting and sand the
edges to smoothly blend in with the Leading edge.
Sand the face of the wing root smooth and flush
with the end rib.
Trim off and sand smooth the small overlaps
where the triangular trailing edge is glued to the
4 x 2 pine strips at the flap and aileron positions.

Tango 3.15
Final wing assembly:
The drill template is printed on
transparent paper. Attach it to the fuselage
with masking tape so that the hole positions
match the spine nuts in the wing mount.
The dashed line and reference to the fuselage
side should help.
The important thing is that the holes
match up, so it is a good idea to open up the
holes on the template and temporarily screw
the wing mounting bolts through it to ensure
perfect alignment.
Remove the wing bolts and place the
wing on the fuselage ensuring that it is
accurately lined up by measuring from
the tail to the wing tips and checking
that both measurements are the same
(See drawing). Once the wing is lined
up, drill two 4mm holes through the
wing in the positions shown by the
template.
Now, check that the wing fits snugly onto the
seat in the fuselage. It may be necessary to
sand away some of the underside sheeting to
clear the captive-nut plate. See picture.
The wing may now be bolted onto the
fuselage to double check that the alignment
is perfect.
Finishing
Before covering the wings, insert the wing servos and the harness, the green 6 pin Multiplex plug
fits flush with the lower planking. The ailerons and flaps are fitted after covering, then the fiberglass
control horns with their reinforcing plates are fitted.
The model may be covered according to your individual tastes and creative ideas.
Some examples may be seen on our homepage www.cad2cnc.ch

Tango 3.15
Centre of Gravity
Adjust the center of gravity by moving the battery or, if necessary, by adding ballast.
The model should balance, as shown in the drawing, in a slightly nose down attitude.
The balance cradle and steel wire are included in the kit, with the holes precut in the fuselage sides.
We are happy to show photos of your built-up
Tango on our homepage.
If you ould care to include short comment, that ould be great.
Thank you very much!
We ish you a lot of fun when flying your Tango!
THE cad2cnc TEAM