Twisted Hobbys CRACK PITTS User manual

Rev: 2015.09.18.v01a page 1
USA Distributor
Twisted Hobbys
www.twistedhobbys.com
MOTOR: 1x 24-26g/1450kv Outrunner
ESC: 1x 10-12 amp
SERVOS: 2x 5g - 1x 9g
PROP: 1x 9x4.7sf - 2s / 8x4.3sf - 3s
BATTERY: 2s or 3s / 450mAh
RADIO: 4 channel
WINGSPAN: 30”
LENGTH: 32”
AUW: 180 to 200 grams
CRACK PITTS
CRACK PITTS *SHOWN WITH OPTIONAL LANDING GEAR

Rev: 2015.09.18.v01a page 2
SAFETY NOTES
 Before assembling and flying this model, read carefully any instructions and warnings of other
manufacturers for all the products you installed or used on your model, especially radio
equipment and power source.
 Check thoroughly before every flight that the airplanes’ components are in good shape and
functioning properly. If you find a fault do not fly the model until you have corrected the
problem.
 Radio interference caused by unknown sources can occur at any time without notice. In such a
case, your model will be uncontrollable and completely unpredictable. Make sure to perform a
range check before every flight. If you detect a control problem or interference during a flight,
immediately land the model to prevent a potential accident.
 Youngsters should only be allowed to assemble and fly these models under the instruction and
supervision of an experienced adult.
 Do not operate this model in a confined area.
 Do not stand in line with, or in front of a spinning propeller and never touch it with any object.
IMPORTANT: PRIOR TO ANY ASSEMBLY
Please Note: after removing kit from shipping box, lay each piece flat on a
hard surface, this will allow the airframe to straighten out if lightly bent
from shipping. Do not worry since EPP is very pliable and can be bent back
if out of shape.

Rev: 2015.09.18.v01a page 3
TWISTED HOBBYS
Website: www.twistedhobbys.com – email: [e-mail]
Thank you for your purchasing a Twisted Hobbys‘ model. Please read through the entire manual before beginning to
build this model. If you have any questions please contact us at the above indicated email address.
WARNING INFORMATION
This R/C Aircraft is not a toy! Read and understand the entire manual before assembly. If misused, it can cause serious bodily harm and
property damage. Fly only in open areas, and AMA (Academy of Model Aeronautics) approved flying sites. Do not over look the warnings
and instructions enclosed or those provided by other manufactures’ products. If you are not an experienced pilot and airplane modeler you
must use the help of an experienced pilot or an authorized flight instructor for the building and flying of this model aircraft.
These instructions are suggestions only on how to assemble this model. There are other ways and methods to do so. Twisted Hobbys has
no control over the final assembly, the materials and accessories used when assembling this kit, or the manner in which the assembled
model, installed radio gear and electronic parts are used and maintained. Thus, no liability is assumed or accepted for any damage
resulting from the use of the assembled model aircraft or from this instruction manual including but not limited to direct, indirect,
incidental, special, and consequential damages. By the act of using this user-assembled product, the user accepts all resulting liability. In
no event shall Twisted Hobbys’ liability exceed the original purchase price of the kit.
SHIPPING DAMAGE
Twisted Hobbys checks each plane before shipping to ensure that each kit is in fine condition. We have no bearing on the condition of any
component parts damaged by use, modification, or assembly of the model. Inspect the components of this kit upon receipt. If you find any
parts damaged or missing, contact Twisted Hobbys immediately. We will not accept the return or replacement of parts on which assembly
work has already begun. Twisted Hobbys reserves the right to change this warranty at anytime without notice.
OUR MISSION
To provide the best products and service to our customers at the lowest prices possible. We take great pride in
our company, our commitment to customer service and in the products we sell. Our online store is designed
to provide you with a safe and secure environment to browse our product catalog.
Thank you for shopping with Twisted Hobbys!

Rev: 2015.09.18.v01a page 4
kit contents
Fuselage Parts
Wing Parts
Double check that you have all the above pictured items. Note -
Some kits might have slight deviations from the above pictured items.

Rev: 2015.09.18.v01a page 5
kit contents (cont.)
Hardware Kit Detail
Tail Surfaces & Hardware Kit
Double check that you have all the above pictured items. Note -
Some kits might have slight deviations from the above pictured items.

Rev: 2015.09.18.v01a page 6
TOOL AND ADHESIVES NEEDED
Tools shown and listed are suggestions only.
Depending on your building technique you may not
need everything indicated – and/or – you may find that
other tools available to yourself may be of benefit to
your Build.
It is also recommended that you have a flat building
surface, one that will accept stick pins and push pins.
An Acrostic Ceiling panel from your local hardware
store fits this bill nicely, and will lay flat on your work
table. Over size / long push pins are available at your
local craft store. These two items are by no means
required, but will aid in the building process, and can
be used for future projects
Lighter
Small Drill Bits
Tape Measure and Ruler
Black Sewing Thread
Welders Glue
Hobby Knife w/new Blade
Needle Nose Pliers
Wire Cutters
Low Temp Hot Glue Gun
Course Sand Paper
Scissors
Small Phillips Screw Driver
Thin and Medium CA
CA Applicator Tips
Activator

Rev: 2015.09.18.v01a page 7
the build
CONSTRUCTION METHODS:
Building surface should be at least 2ft x 4ft and at. Weights or some small heavy objects will be handy for holding things in place
during the time glue is setting.
Welders glue is used for FOAM TO FOAM joints. Thin and Medium CA are used on the PLASTIC TO FOAM and CARBON TO FOAM
joints. When using the Welders glue for a butt joint, apply a thin lm to each surface, allow to sit for approx ve minutes and
then assemble. Note that this method will create a nearly instant bond, so locate carefully when bringing the two pieces together. If
alignment is necessary or a slip joint, do not allow the glue to tack up, simple apply and join immediately, you will have several
minutes to locate the two parts before the glue sets up. In most cases the parts being glued can be handled with care in 30 minutes,
full cure is approx 24 hours.
The above picture items will be needed to nish the model.
A power combo (Twisted Hobbys’ Combo pictured above), a
battery and a fresh tube of Welders. Note - the Battery,
Receiver and Welders are NOT part of the power combo,
everything else shown is.
Start the build by locating the two wings, the elevator and
the rudder. Fold back as shown and weigh them down for
about an hour to loosen up the hinge area. Now is also a
great time to setup your radio and to test that all your
electronics are functioning properly.

Rev: 2015.09.18.v01a page 8
Find the horizontal fuselage piece and
the elevator. Join them together using
the Tack Up Method.
Notice that the two parts are “keyed” to
insure proper orientation.
Once the glue has tacked up, bring the
two pieces together, press rmly to get
a good bond.
Press the servo into the cut out. It will
stick up a little on the near side. Servo
arms will be install later. They would
just get in the way at this time.
Install the servo as shown, from the
underside/bottom of the horizontal
fuselage piece. Note - no glue at this
time, gluing the servos in will be done
towards the end of the build.
Flip the assembly over and locate your
elevator servo. If using the power
combo servos, the cut out will match
perfectly, if using other servos, some
trimming may be necessary.

Rev: 2015.09.18.v01a page 9
Locate the vertical fuselage section, and
put a fresh blade in your hobby knife.
Split the vertical fuselage section down
the center of the tabs. Note, the tabs
have small “V”s cut in them to help
locate the exact center.
Once all the tabs are split, you should
have something like pictured above.
Once you are satised with the test t,
separate the two pieces and re-
assembly using the Wet Method. Make
sure and apply glue to all the mating
surfaces and tabs.
Test t the lower vertical fuselage to the
horizontal assembly as shown. All tabs
should fully engage, and the two pieces
should be square to each other.
Split/Separate the small tab for the slot
shown above so that it is free as
pictured.

Rev: 2015.09.18.v01a page 10
Make sure all the tabs are fully seated
as was done with the test t, wipe away
any extra glue and weigh down so that
everything will dry at.
While the glue is still wet, check for
squareness and tweak a little as
needed.
Locate the beveled foam trusses as
shown above.
Make sure there is a good bond. Use a
gentle touch when pressing the truss to
the fuselage. Pressing too hard will
cause the fuselage member to be out of
square.
Align the square end up with the edge
of the hinge relief as pictured above,
and attach the truss at 45 degrees to
the two fuselage members.
Stating with the side shown, apply a
medium bead of Welders the entire
length of the beveled area.

Rev: 2015.09.18.v01a page 11
Next is the far side, apply a medium
bead of Welders as with the other side,
but leave approx 4in free of glue on the
pointed end.
Attach the truss like was done on the
other side and note that there is approx
4in free of glue. This will allow access to
all the wires and will be secured to the
fuselage in a later step.
Make sure the two fuselage pieces are
still square to each other, allow the glue
to dry before moving on to the next
step.
Locate the top vertical half of the
fuselage. Test t, make sure that all the
tabs and slots are able to fully engage.
Make sure the wire does not get
bunched up under the servo in the hole
and that the servo is fully installed and
sitting rmly on it’s anges as pictured
above. Do Not Glue at this time.
Locate the rudder servo. If using the
Twisted Hobbys power combo servos,
no trimming will be need. Fish the wire
thru on the same side as the elevator
wire, and press the servo into it’s slot.

Rev: 2015.09.18.v01a page 12
Once happy with the t up, remove it
and apply a medium bead of Welders to
the mating surfaces. Avoid the servos
and areas around were the slits are in
the vertical fuselage pieces.
Starting from the front... align the nose
surfaces and work towards the tail
engaging the slots along the way. Press
and wiggle to make sure the tabs are
full seated into their respective slots.
The nose surfaces should all be ush
as pictured above. In a later step, this
is where the motor mount will attach
to, and it is important that they are
even to create a at surface.
Locate the two wood fuselage stiffeners
as pictured above. They should be
approx 2x9x90 and 2x9x150
millimeters.
Once happy with the squareness. Set
the assembly aside to dry. Stand the
assembly up as shown, this will avoid
any awkward stress to the airframe
while the glue is drying.
While the Welders is still wet, check for
squareness along the length of the
fuselage. Tweak as needed for a nice
and true assembly.

Rev: 2015.09.18.v01a page 13
Stick the longer of the two pieces of
wood thru the reward slot in a diagonal
fashion, right at the intersection of the
two fuselage pieces.
Position so that the length of wood
matches the approx length of the slot in
the foam.
Apply a thin coat of Welders to both
sides of the exposed wood stiffener.
Also squeeze some Welders into the
slots.
Apply a thin coat of Welders to both
sides of the shorter fuselage stiffener.
Make sure the stiffener is centered in
the foam and wipe away any extra glue
that is left on the surface of the
fuselage pieces. Use a paper towel and
only make one pass.
Press the wood stiffener into position as
shown, adjusting it’s position up or
down as needed to match the exact
length of the slot in the foam.

Rev: 2015.09.18.v01a page 14
Also squeeze some Welder into the slot
in the fuselage.
Install the stiffener into the fuselage
from the same side that you applied the
glue from.
Wipe away any extra glue with a paper
towel, and again, only one pass.
Multiple passes will ruin the printed
graphics.
With your hobby knife remove the tabs
and scrap material from the slot
cutouts of each of the wing.
Locate the two wings, wing struts and
wood spars as shown. Wing spars are
approx 23.6 inches long and the spars
for the struts are approx 5.9 inches
long.
Check for squareness in the area of the
stiffeners and adjust if necessary. Set
the assembly aside some where safe to
dry... stand it on it’s nose like what was
done previously.

Rev: 2015.09.18.v01a page 15
Once all the tabs and scrap material is
removed, you should be able to spread
the wing as shown above.
Apply a medium bead of Welders to
each side of the wing spar.
Spread the wing, and while keeping the
wing slot spread, lower the spar into
position, and then allow the foam to
relax.
Repeat with the other wing and then set
aside with weights and/or stick pins
and allow them to dry completely before
handling.
Wipe away any glue the squishes out.
Make sure and only do a single pass,
multiple passes will wreck the printed
graphics.
Make sure the spar is ush with the
surface of the wing. Press together
along the length of the wing to ensure
that there is a good bond between the
wing and the spar.

Rev: 2015.09.18.v01a page 16
As with the wing spars, apply a bead of
Welders to both sides of the strut spar.
Spread the strut as shown and insert
the spar.
Push it in all the way, making sure that
it is ush with both sides and wipe
away any extra glue.
While all that is drying, locate the horn
kits from your servos, the plastic horn
set that came with the kit, and the
adjustable links as shown above.
Repeat the process with the other side.
Note there is a left and right, but they
are symmetrical so it does not matter
how you build them.
Set aside with weights and/or stick
pins and allow to dry.

Rev: 2015.09.18.v01a page 17
If using the power combo servos you
should have stock horns like pictured
above, if using other servos, nd the
horns that came with them that are
similar.
From the under side of the stock horn,
apply some Welders to each of the
arms.
Install the differential horn as shown, if
the center hole is a little big, just center
it in the opening, if is not super critical,
just get it as close as you can.
Repeat the previous two steps with the
other tail servo horn and set all the
items aside to dry.
Above picture shows the extension
attached to the horn from the under
side and butted all the way up against
the center part of the stock horn.
Same basic process for the tail servo
horns... apply some Welders to the
under side of the stock horn and attach
the extension.

Rev: 2015.09.18.v01a page 18
Locate the two aileron control surface
horns and adjustable link pieces as
shown above. Note that the aileron
horns are the ones like pictured above
with the lightening holes.
Install the main adjustable link part
into the hole as shown. Note - it is
important to make a LEFT and RIGHT
version.
Press on the keeper clips with the
cupped side installed as pictured above,
repeat this for both horns, again
remembering that there is a left and
right.
Squeeze some Welders into the slit.With a sharp hobby knife, nish cutting
the slot all the way thru.
Next the gang horns will be installed on
the trailing edges of both wings. There
are pre-cut slots on the sides pictured
above, but they need to be nish cut all
the way thru.

Rev: 2015.09.18.v01a page 19
Put a medium skim coat on to both
sides of the gang horn.
Slide the gang horn into the slot. Make
sure that it is ush with both the upper
and lower surface of the wing.
Position the gang horn far enough in so
that it is ush with the trailing edge of
the wing as pictured above.
Aileron control horns are to be installed
next. These install into the top surface
of the bottom wing. there are pre-cut
slots, just cut all the way through like
was done on the gang horns.
Repeat with the remain three positions.
Note that the precut slots are on the
top of the bottom wing, and the bottom
of the top wing, as pictured above.
Wipe away any extra glue.

Rev: 2015.09.18.v01a page 20
Squeeze some Welders into the slot. Put a medium skim coat on both sides
of the horn in the area that gets buried
into the wing.
Install the horn into the wing. Note that
the main part of the adjustable link
should be facing outward
Repeat with the other side. Again notice
the orientation of the adjustable links.
Wipe away any extra glue.
Flip the wing over and check to see that
the prole of the horn matches the
prole of the hinge cut out. This
indicates that the horn is in the proper
position.