Kraga Kodo User manual

Kodo build guide 1.4.1
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Development of a new plane and support of the old ones is very time consuming. Only with your
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KRAGA KODO
ITEM NO. PART NUMBER
PRINTED AS
QTY.
1 boom_10x9_520
-
1
2 fuse_bottom_spar_2x1_425
-
1
3 aileron_spar_2x1_270
-
2
4 fuse_left_spar_2x1_407
-
1
5 fuse_right_spar_2x1_407
-
1
6 hinge
-
10
7 main_wing_spar_4x3_375
-
2
8 main_wing_spar_6x4_375
-
2
9 servo_common
-
2
10 spar_joiner_3_220_b
-
1
11 spar_joiner_4_250_f
-
1
12 tail_main_spar_2x1_b_145
-
2
13 tail_main_spar_2x1_f_132
-
2
14 tail_mov_spar_2x1_105
-
2
15 tip_wing_spar_4x3_b_400
-
2
16 tip_wing_spar_4x3_f_397
-
2
17 boom_lines_holder
SOLID
3
18 fuse_0
SOLID
1
19 fuse_1
SOLID
1
20 fuse_2
SOLID
1
21 fuse_3
SOLID
1
22 fuse_4_sk3_2836
SOLID
1
23 canopy_front
SOLID
1
24 canopy_rear
SOLID
1
25 tail_boom_mount
SOLID
1
26 tail_main_L_0
SHELL
1
27 tail_main_L_1
SHELL
1
28 tail_main_R_0
SHELL
1
29 tail_main_R_1
SHELL
1
30 tail_mov_L_0
SHELL
1
31 tail_mov_L_1
SHELL
1
32 tail_mov_R_0
SHELL
1
33 tail_mov_R_1
SHELL
1
34 center_wing_L_0
SHELL
1
35 center_wing_L_1
SHELL
1
36 center_wing_L_2
SHELL
1
37 center_wing_L_3
SHELL
1
38 center_wing_R_0 SHELL
1
39 center_wing_R_1 SHELL
1
40 center_wing_R_2 SHELL
1
41 center_wing_R_3 SHELL
1
42 tip_wing_L_0
SHELL
1
43 tip_wing_L_1
SHELL
1
44 tip_wing_L_2
SHELL
1
45 tip_wing_L_3
SHELL
1
46 tip_wing_L_4
SHELL
1
47
tip_wing_R_0
SHELL
1
48 tip_wing_R_1
SHELL
1
49 tip_wing_R_2
SHELL
1
50 tip_wing_R_3
SHELL
1
51 tip_wing_R_4
SHELL
1
52 aileron_L_0
SHELL
1
53 aileron_L_1
SHELL
1
54 aileron_L_2
SHELL
1
55 aileron_L_3
SHELL
1
56 aileron_R_0
SHELL
1
57 aileron_R_1
SHELL
1
58 aileron_R_2
SHELL
1
59 aileron_R_3
SHELL
1
60 servo_common_mount_wing_front_L
SOLID
1
61 servo_common_mount_wing_rear_L
SOLID
1
62 servo_common_mount_wing_front_R
SOLID
1
63 servo_common_mount_wing_rear_R
SOLID
1
64 servo_mount_fuse SOLID 1
65 wing_horn_L
SOLID
1
66 wing_horn_R
SOLID
1
67 tail_horn_L
SOLID
1
68 tail_horn_R
SOLID
1
69 end_cap_L SOLID 1
70 end_cap_R SOLID 1

Printing
You need to use two printing methods to print all parts:
1. Solid parts (fuse and accessories - all blue parts). Use dense infill.
This is common way of printing objects and these parts should be
printable on every printer.
2. Shell parts (wings - all orange parts). Use 0% infill and
no horizontal surfaces (thickness of the shell is one
layer). Only this way you can achieve required weight of
the plane.
You can check what method to use on what part in bill of materials table.
Nozzle size: 0.4mm
Layer thickness: 0.19mm
Rafts: yes
You can use any material you like, only limitation is high temperature from ironing when covering
assembled parts. Heat from the iron can deform the parts. Although I was not able to damage any
part and I tried to cover many materials (ABS, PLA ...), please test film covering on your testing
part.
One of the goals when designing KRAGA models was to use minimal or no support during printing.
Removing support after printing is big pain and you can easily destroy your part. That is the reason
why you should use default orientation of all parts during printing. There are only two parts from
whole plane which require support, these are from plane fuselage and are printed as solid. The rest
of the plane should be support-free.
I strongly recommend to mark every printed part with it's name (I'm using masking tape for that).
There are many parts in this plane and from each part there is also mirror side which can easily
cause confusion during assembly.
I also recommend to print parts in bulks, especially smaller parts like ailerons or moving parts on
the plane tail. Otherwise there is not enough time for material cooling in each layer and you might
end up with rough layers, ugly edges or print fail.
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Parts choices
For some parts there are more options and it is up to you what you will choose depending on what
motor and servos are you going to use.
Choices based on used motor:
•no motor (pure sailplane variant): print fuse_4_no_motor and fuse_5
•Turnigy Aerodrive SK3 - 2836 brushless outrunner motor: print fuse_4_sk3_2836 (fuse_5
not needed)
•other motor: print fuse_4_uni, for this option you need to drill motor screw holes manually
(fuse_5 not needed)
Choices based on used servo in the wing:
•servo_hxt_900_mount: will fit HXT900 servo A = 2.4 mm, B = 23
mm, C = 32 mm, D = 12 mm, E = 16 mm
•servo_common_mount: will fit A = 2 mm, B = 23 mm,
C = 32 mm, D = 12 mm, E = 19 mm
•servo_custom_mount: you can cut out slots yourself
based on your needs
Most important dimension is A, if that one fits you but the other ones not try to print the mounts anyway and test-fit your servo.
Choices based on used servo in the fuselage:
•servo_mount_fuse: will fit servos with B = 23 mm, D = 12 mm
•servo_mount_fuse_common: you can cut out whatever hole you need
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Preparation for assembly
KRAGA Kodo plane consists of parts that are printed and parts that you need to buy separately
(they are not included in sold product) – carbon tubes, rods and pinned hinges.
List of required parts:
dimensions count
carbon tube ⌀ 2x1 mm ↔ 1 m 3
carbon tube ⌀ 4x3 mm ↔ 1 m 3
carbon tube ⌀ 6x4 mm ↔ 1m 1
carbon tube ⌀ 10x9 mm ↔ 520 mm 1
carbon rod ⌀ 3 mm ↔ 220 mm 1
carbon rod ⌀ 4 mm ↔ 250 mm 1
covering film ↔ 2 m 1
push rod * ↔ 80 cm 2
pinned hinge ↕ ↔ 16x28 mm or smaller 10
folding propeller up to ↔ 10 inch 1
spinner ⌀ 40 mm 1
⌀ 2x1 mm – means tube with outer diameter of 2mm and inner diameter of 1mm
⌀ 3 mm - means rod with diameter of 3mm
* you can use other linkage system than flexible push rod (push rod made from carbon tube ...)
And of course you need all the common accessories like clevises, push rods for ailerons, (horns are
printed so you don't need those) and electronics (motor, esc, 4 micro servos).
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Next step is to cut carbon tubes and rods into smaller pieces, which will be used as spars, joiners or
boom of the plane. Don't forget to mark every piece to avoid confusion during the assembly.
part dimensions count
aileron carbon spar ⌀ 2x1 mm ↔ 270 mm 2
fuse bottom carbon spar ⌀ 2x1 mm ↔ 425 mm (*438 mm) 1
fuse side carbon spar ⌀ 2x1 mm ↔ 407 mm (*420 mm) 2
tail main carbon spar front ⌀ 2x1 mm ↔ 132 mm 2
tail main carbon spar back ⌀ 2x1 mm ↔ 145 mm 2
tail mov carbon spar ⌀ 2x1 mm ↔ 105 mm 2
tip wing carbon spar front ⌀ 4x3 mm ↔ 397mm 2
tip wing carbon spar back ⌀ 4x3 mm ↔ 400 mm 2
center wing carbon spar back ⌀ 4x3 mm ↔ 375 mm 2
center wing carbon spar front ⌀ 6x4 mm ↔ 375 mm 2
carbon boom ⌀ 10x9 mm ↔ 520 mm 1
wing joiner carbon rod back ⌀ 3 mm ↔ 220 mm 1
wing joiner carbon rod front ⌀ 4 mm ↔ 250 mm 1
* dimensions for pure sailplane variant
TIP: How to cut carbon spars. Wrap masking tape
around carbon spar and mark cut position. Use rotary
tool to cut the spar. Work outside or in room with
good ventilation. Use breathing mask to avoid
inhaling carbon dust! After cutting wipe out carbon
dust from the spars using wet tissue.
Remove support legs from all parts. Also sand all sharp edges
and printing imperfections to avoid covering foil damage.
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Assembly
This assembly will describe always left side of the plane when it comes to symmetric parts. It is
recommended to use medium viscosity CA glue. You can use CA glue accelerator for faster curing
time. Dry fit all the parts before gluing them together.
Center wing
Assembly left center wing as sketched above. Carbon spars should be aligned flush with base of
center_wing_L_0 part. When all the parts are on their position, put glue on contact points where
carbon spars are touching printed parts.
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Tip wing
Assembly left tip wing as sketched above. You have an option here to use common servo mounts or
servo mounts for HXT900. Don't forget to insert servo mounts into tip_wing_L_0 part when
leading spars through. Carbon spars protrude from base of tip_wing_L_0 so that they can be
inserted into empty leading spar holes on the center wing. Do not forget to center your servos before
gluing them in. Check also that your clevises fit servo arm holes, drilling them when servo is in
place could damage the wing.
You can choose to use end cap for the wing tip. It is not mandatory, but it makes film covering a
little bit easier.
When all the parts are on their position, put glue on contact points where carbon spars are touching
printed parts.
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Aileron
Assembly left aileron as sketched above. Don't forget to insert wing_horn_L part into aileron_L_0
when leading spar through. Carbon spars should be aligned flush with base of aileron_L_0 part.
When all the parts are on their position, put glue on contact points where carbon spars are touching
printed parts.
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Wing
To complete wing assembly first glue together center wing and tip wing. Only then continue with
gluing hinges and aileron.
Some hinge slots are not deep enough to fit whole hinge length. Shorten all
hinges as shown on the picture. It has no benefit in terms of added stiffness
of rigidity to use whole hinge arm length as only small hinge area is in
contact with the wing.
Be careful when using glue near pinned part of the hinge. First insert the hinge into hinge hole and
then apply the glue from inner side of the wing. Do the same when gluing aileron to hinge. First
insert all hinges into hinge holes on aileron and then apply glue from inner side of aileron. Make
sure that aileron has enough space for moving from every side.
When the wing is assembled lead servo cable through the wing. The cable should come out of the
wing near servo cable hole in fuselage.
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