Carf-Models Composite-ARF Extra 300L User manual

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Composite-ARF Extra 300L (2.12m/84”)
Instruction Manual
Composite-ARF Extra 300L, 2.12m (84”)
TAVS Technology version 1.0

Instructions for Extra 300L IMAC-Airplane
Thank you very much for purchasing our Composite-ARF Extra 300L 2.12m (84” span) all com-
posite aircraft, made with the revolutionary Total Area Vacuum Sandwich (TAVS) technology
Please note that some photos in these instructions show our 2 x 2 Extra, which has almost iden-
tical assembly in many areas (especially wings and stabs), but of course the colour scheme is
different - so don’t get confused by this !
If you want a full-color version of this manual, you can download it free of charge from our web-
site, as an Adobe Acrobat .pdf file and print it. Just go to the Extra 2.12 page on our website, and
click on the link named ‘Download Instruction Manual’ link above the top photo of the product.
NB: Please read all of the important information on pages 3 - 7 of this Instruction Manual
carefully before starting the assembly of your Extra 300, especially if this is one of your
first fully-composite ARF type aircraft.
Before you get started building and setting-up your aircraft, please make sure you have read this
Instruction Manual several times, and understood it. If you have any questions, please don’t
hesitate to contact us. Below are the contact details:
Email: [email protected]
or [email protected]
Telephone: Phone your C-ARF Rep!!! He will be there for you.
Website: http://www.composite-arf.com
Liability Exclusion and Damages
You have acquired a kit, which can be assembled into a fully working R/C model when fitted out
with suitable accessories, as described in the instruction manual with the kit.
However, as manufacturers, we at Composite-ARF are not in a position to influence the way you
build and operate your model, and we have no control over the methods you use to install,
operate and maintain the radio control system components. For this reason we are obliged to
deny all liability for loss, damage or costs which are incurred due to the incompetent or incorrect
application and operation of our products, or which are connected with such operation in any
way. Unless otherwise prescribed by binding law, the obligation of the Composite-ARF compa-
ny to pay compensation is excluded, regardless of the legal argument employed.
This applies to personal injury, death, damage to buildings, loss of turnover and business,
interruption of business or other direct and indirect consequent damages. In all circumstances
our total liability is limited to the amount which you actually paid for this model.
BY OPERATING THIS MODEL YOU ASSUME FULL RESPONSIBILITY FOR YOUR ACTIONS.
It is important to understand that Composite-ARF Co., Ltd, is unable to monitor whether you
follow the instructions contained in this instruction manual regarding the construction, operation
and maintenance of the aircraft, nor whether you install and use the radio control system
correctly. For this reason we at Composite-ARF are unable to guarantee, or provide, a
contractual agreement with any individual or company that the model you have made will
function correctly and safely. You, as operator of the model, must rely upon your own expertise
and judgement in acquiring and operating this model.
Composite-ARF Extra 300L (2.12m/84”) [email protected]
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Important Supplementary Notes
Pre-Assembly Checks:
At Composite-ARF we take every possible precaution to make sure that all our products are
carefully checked before they leave the factory - but of course it is always possible that human
error creeps in occasionally with high-volume production, and that an important part has been
incorrectly installed or glued into position.
Therefore we strongly recommend that you double-check the following critical structural com-
ponents before starting the assembly of your aircraft - and also regularly before every flying ses-
sion as a hard landing, shock loads during transport, or vibrations from unbalanced propellers,
etc., could all damage the glue joints to these critical components that ensure the structural
integrity of your plane, and the safety of people nearby.
1) Check that the plastic wing bolts, and the front and back fibreglass rod anti-rotation dow
els, are securely glued into the wing root ribs. Check that the fibreglass rod anti-rotation
pins are securely glued into the front of the stabiliser root ribs.
2) Check that the fibreglass sleeves for the wing and stab spar tubes are securely glued into
the fuselage.
3) Check that the alloy wing tube and carbon stab tubes are the correct lengths, as shown in
the hardware list at the end of these instructions, not bent or damaged at all, and that they
fit into the sleeves in the fuselage and wings/stabs without too much ‘slop’.
4) Check that the plywood landing gear support plates are securely glued into the bottom of
the fuselage, and reinforced with a layer of fibreglass cloth and epoxy resin.
If you see any of these important joints that don’t seem to have enough glue on them, then light-
ly sand the area with 120 grit sandpaper, clean the area carefully with Acetone (or denatured
alcohol or similar) on a paper towel, and apply some 30 minute or laminating epoxy and micro-
balloons mixture when you are mixing it for use in another part of the normal assembly.
Pre-Flight Checks:
Before every session check that all the model’s systems function correctly, and be sure to carry
out a range check. The first time you fly any new model aircraft we strongly recommend that you
enlist the help of an experienced modeller to help you check the model and offer advice while
you are flying. Be certain to use the recommended CG position and control surface travels. If
adjustments are required, carry them out before operating the model. Be aware of any instruc-
tions and warnings of other manufacturers, whose product(s) you use to fly this aircraft.
Make sure that your wing and stab spar tubes are not damaged. Check that the anti-rotation pins
for the wings and stabiliser are not loose. Check that the plastic wing retaining nuts are tight, that
the M3 bolts retaining the horizontal stabilisers onto the carbon tube are tight, and that the rud-
der hinge wire cannot come out with a piece of clear tape.
Please don’t ignore our warnings, or those provided by other manufacturers. They refer to things
and processes which, if ignored, could result in permanent damage or fatal injury
Attention !
This IMAC-Aircraft is a high-end product and can create an enormous risk for both pilot and
spectators, if not handled with care, and used according to the instructions. Make sure that you
operate your Extra according to the AMA rules, or those laws and regulations governing model
Composite-ARF Extra 300L (2.12m/84”) [email protected]
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Composite-ARF Extra 300L (2.12m/84”) [email protected]
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flying in the country of use.
The engine, servos and control surfaces have to
be attached properly. Please use only the
recommended engines, servos, propellers, and
accessories. Make sure that the ‘Centre of
Gravity’ is located in the recommended place.
Use the nose heavy end of the CG range for your
first flights. A tail heavy plane, especially in the
first flight, can be an enormous danger for you
and all spectators. Fix any weights, and heavy
items like batteries, very securely into the plane.
Make sure that the plane is secured properly
when you start up the engine. Have a helper hold your plane from the tail end or from behind the
wing tips before you start the engine. Make sure that all spectators are behind, or far in front, of
the aircraft when running up the engine.
Make sure that you range check your R/C system thoroughly before the 1st flight. It is absolute-
ly necessary to range check your complete R/C installation first WITHOUT the engine running.
Leave the transmitter antenna retracted, and check the distance you can walk before ‘fail-safe’
occurs. Then start up the engine, run it at about half throttle and repeat this range check with the
engine running. Make sure that there is no range reduction before ‘fail-safe’ occurs. Only then
make the 1st flight. If the range with engine running is less then with the engine off, please con-
tact the radio supplier/engine manufacturer and DON’T FLY at that time.
Check for vibrations through the whole throttle range. The engine should run smoothly with no
unusual vibration. If you think that there are any excessive vibrations at any engine rpm’s, DON’T
FLY at this time and check your engine, spinner and propeller for proper balancing. The light-
weight sandwich composite parts don’t like too much vibration and they can suffer damage. The
low mass of all the parts results in a low physical inertia, and any excess vibrations can affect
the servos and linkages.
Fully-composite aircraft structure
All the parts are produced in negative molds, manufactured using vacuum-bagged sandwich
construction technology. All parts are painted in the molds, either single color or designer
schemes. A production method called TAVS (Total Area Vacuum Sandwich), enables us to pres-
ent this aircraft with incredible built-in strength, while still being lightweight, and for a price that
nobody could even consider some years ago. This production process has huge advantages, but
a few disadvantages also. These facts need to be explained in advance for your understanding.
Description of Parts
The Wings:
Both wing halves are made in negative moulds, and fully
vacuum bagged, using only 2 layers of 2 oz. cloth in com-
bination with a very hard 2 mm foam sandwich to form a
hard and durable outer skin.
The ailerons are hinged already for you - laminated in the
mould and attached to the wing with a special nylon hinge-
NO !!!
Secure the plane
before starting
the engine.
DANGER ZONES
NO NO

cloth, sandwiched between the outer skin and the foam.
This nylon hinge is 100% safe and durable. You will never
have to worry about breaking it, or wearing it out. There is
no gap at all on the top wing surface, and there is a very
narrow slot in the bottom surface, where the aileron slides
under the main wing skin during down throw. This means
that the hinge axis line is on the top surface of the wing, not
in the centre. This is NOT a disadvantage, if you program
in about 10% NEGATIVE aileron differential in your trans-
mitter. This means that the ‘down’ throw needs to be about 10% more than the up throw. Why?
Because the axis of the hinge is not at the centreline of the aileron, so it moves slightly in and
out when operated, and the aileron gets a little "bigger" in surface area when moving up, and
"smaller" when moving down.
The bottom slot needs some explanation, too. The cut line is exactly in the correct position so
that the aileron slides under the wing skin smoothly. If the cut was a few mm forward or back, it
would not work properly. So, make sure that the lip is not damaged, and that the aileron slides
under this lip perfectly. It will NOT lock at any time, if the lip is not damaged. If damage occurs
to the lip, you can cut off 2-3 mm, but you should NEVER need to cut off more than this.
The Fuselage:
The fuselage is also made in negative moulds, constructed using TAVS technology. The main
internal parts for the landing gear, composite engine firewall and exhaust tunnel, wing and stab
spar supports are glued in during manufacture, to ensure accurate location and reduce the
assembly time for you. There is no need to even check the incidences - you can be assured that
these are already set in the molds so that no adjustment is necessary.
The all-composite combined firewall and exhaust tunnel is
factory-installed and aligned for your convenience, and
contributes greatly to the strength of the airframe.
The pre-installed landing gear mount is strong and does-
n’t need any extra reinforcement. You have an extremely
light weight fuselage, and the gear loads need to be led
into the structure gently. The new landing gear is a flexible
design, which works very much like shock absorbers. Do
not change or modify it, as the results would only be neg-
ative.
The Stabilisers:
The stab parts are also vacuum bagged sandwiched. The
rudder is hinged with a Ø 2mm steel wire, and the eleva-
tor control surfaces are factory-hinged with proprietary
hinge-points, 4 on each stab.
The rudder and elevator design allows for at least 45
degrees throw. The horizontal stabs are mounted with one
Ø 14mm carbon tube and one 6mm anti-rotation pin each.
Servo Screws:
Fix the all the servos into the milled plywood servo mounts
using the 2.9 Ø x13mm sheet metal screws provided in
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Centreline of hinge axis
Phenolic control horn

the kit, not the standard screws normally supplied with ser-
vos by the servo manufacturer. This is because all the
holes in our milled servo mounts are 2mm diameter, due to
our CNC manufacturing process, and this is too big for the
normal screws.
Take Care:
Composite sandwich parts are extremely strong, but fragile
at the same time. Always keep in mind that these contest
airplanes are designed for minimum weight and maximum
strength in flight. Please take care of it, especially when it
is being transported, to make sure that none of the critical
parts and linkages are damaged. Always handle your air-
plane with great care, especially on the ground and during
transport, so you will have many hours of pleasure with it.
Tools and Adhesives
Tools etc:
This is a very quick and easy plane to build, not requiring special techniques or equipment, but
even the building of Composite-ARF aircraft requires some suitable tools. You will probably have
all these tools in your workshop anyway, but if not, they are available in all good hobby shops,
or hardware stores like "Home Depot" or similar.
1. Sharp knife (X-Acto or similar)
2. Allen key set (metric) 2.5mm, 3mm and 4mm.
3. Sharp scissors
4. Pliers (various types)
5. Wrenches (metric)
6. Slotted and Phillips screwdrivers (various sizes)
7. M3 tapping tool (metric)
8. Drills of various sizes
9. Dremel tool (or Proxxon, or similar) with cutting discs, sanding tools and mills.
10. Sandpaper (various grits), or Permagrit sanding tools (high quality).
11. Carpet, bubble wrap or soft cloth to cover your work bench (most important !)
12. Clear Car wax polish (for protecting painted areas close to glue joints).
13. Denaturised alcohol, or similar (for cleaning joints before gluing)
14. An Incidence meter is helpful for engine thrustline alignment.
Adhesives:
Not all types of glues are suited to working with composite parts. Here is a selection of what we
normally use, and what we can truly recommend. Please don’t use inferior quality glues - you will
end up with an inferior quality plane, that is not so strong or safe.
1. CA-Glue ‘Thin’ and ‘Thick’ types. We recommend ZAP, as this is a very high quality.
2. 5 minute-epoxy (highest quality seems to be Z-Poxy)
3. 30 minute epoxy (stressed joints must be glued with 30 min and NOT 5 min epoxy).
4. Epoxy laminating resin (12 - 24 hr cure) with hardener.
5. Milled glass fibre, for adding to slow epoxy for strong joints.
6. Microballoons, for adding to slow epoxy for lightweight filling.
Composite-ARF Extra 300L (2.12m/84”) [email protected]
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We take great care during production and Quality Control at the factory to ensure that all joints
are properly glued, but strongly recommend that you double-check these yourself and re-glue
any that might just have been missed. See ‘Pre-assembly’ notes on page 3.
When sanding areas on the inside of the composite sandwich parts to prepare the surface for
gluing something onto it, do NOT sand through the layer of lightweight glasscloth on the inside
foam sandwich. It is only necessary to rough up the surface, with 80/120 grit, and wipe off any
dust with acetone or de-natured alcohol (or similar) before gluing to make a perfect joint. Of
course, you should always prepare both parts to be joined before gluing for the highest quality
joints. Don’t use Acetone or paint ‘thinners’ for cleaning
external, painted, surfaces as you will damage the paint.
Tip: For cleaning small (uncured) glue spots or marks off
the painted surfaces you can use old-fashioned liquid cig-
arette-lighter fuel, (eg: ‘Ronsonol’ or equivalent). This
does not damage the paint, as Acetone and many other
solvents will, and this is what we use at the factory.
At Composite-ARF we try our best to offer you a high qual-
ity kit, with outstanding value-for-money, and as complete
as possible. However, if you feel that some additional or
different hardware should be included, please feel free to let
us know. We know that even good things can be made bet-
ter !
Email us: [email protected].
Accessories
This is a list of the things you may need to get your Composite-ARF Extra 2.12m (84”) into the
air. Some of them are mandatory, some of them can be chosen by you. What we list here are
highly recommended parts, and have been thoroughly tested.
1. Power servos (min. 5 ). We recommend JR 8511/8611’s or Futaba S9351’s for the ailerons,
elevators & rudder.
2. 5 metal servo output discs, 1” or 25mm diameter. We strongly recommend that you
use metal discs instead of the standard plastic discs when using hi-torque digital servos.
3. Throttle servo for gas/methanol motor. Any standard servo will do.
4. Aluminium Spinner 82 - 88 mm dia (3.25 - 3.5”), eg: Tru-Turn.
5. Main wheels 65 - 70mm (2.5 - 3"). Kavan Light or Dubro wheels are recommended.
6. Engine DA-50, or equivalent. The instructions show this engine, but you could use any
other 35 - 50cc gas engine, eg: Zenoah 38 or ZDZ 40 - or a big 4 stroke (eg: OS140/160,
YS140/160).
7. Exhaust system, muffler or minipipe if using gas or methanol engine. C-ARF can supply
headers and mini-pipes for the DA-50 as an option (see our website).
8. High quality servo extension cables, with gold connectors. High quality
receiver and ignition switches, ‘Y’ leads, ferrite chokes etc.
9. Receiver battery. Either one or two 1200 -1400 mAH NiMH (or Li-Ion/Duralite) packs.
10. Fuel tank (500 - 700 ml) with gasoline stopper. Dubro #424 fits perfectly.
11. Propeller, to suit motor choice. Carbon 23 x 8 is suitable for the DA-50
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Lighter fluid is excellent for clean-
ing small marks, clear wax, uncured
glue, or similar off the painted sur-
face of the plane.

About the Extra 2.12m (84”)
The Composite-ARF Extra 2.12m is far more pre-fabricated than our original 2 x 2 Extra.
The fin post, rudder hinging, composite firewall and exhaust tunnel, wing and stab anti-rotation
pins, wing fixing bolts, landing gear support..... all these are now factory completed for you. In
addition a clear cockpit canopy is now included, for those of you that prefer this to the fibre-
glass canopy. The elevators are now factory-hinged for you, using 4 Robart pin-hinges per
side - to allow additional throw for those wild 3D manoeuvres that this plane loves to do!
A very complete hardware pack is included, with almost everything needed to complete the
servo/motor and landing gear installation in the plane. Of course, all the small wood parts, phe-
nolic servo arm extensions and control horns, milled plywood firewall and servo mounts are
also included in the kit.
The flying characteristics of the 2.12m Extra are quite similar to the original 2 x 2m Extra. The
5% larger wing allows a bit more overall weight without increasing the wing loading, and gas
engines of between 40 and 50 cc power the new 2.12m Extra ballistically!
Great performance, very similar to the full blown Extra 300s of Composite-ARF, very neutral,
light-winged and extremely precise. The 2.12m Extra is an ideal ‘Everyday Workhorse’, allow-
ing you to keep the more sophisticated larger planes for those "special days".
......And all this at a never before achieved value-for-money price !
Did you read the hints and warnings above and the instructions carefully?
Did you understand everything in this manual completely?
Then, and only then, let’s start assembling your Composite-ARF Extra ...
Composite-ARF Extra 300L (2.12m/84”) [email protected]
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A view of the complete Extra 2.12m (84”) kit contents - Product #721000

Building Instructions
General Tips:
We recommend that you follow the order of construction shown in this manual for the fuselage,
as it makes access to everything easier and saves time in the end.
The first thing to do is protect the finished paint on the outside of the model from scratches and
dents during building - so cover your work table with a piece of soft carpet, cloth or bubble-plas-
tic. The best way to stop small spots of glue getting stuck to the outside painted surfaces is to
give the whole model 2 good coats of clear car wax first, but of course you must be sure to
remove this 100% properly before adding any additional paint, decals or trim. Alternatively you
can cover the majority of the fuselage with the bubble-plastic used to pack your model for ship-
ping, fixed with paper masking tape, which also protects it very well.
When sanding areas inside of the fuselage to prepare the surface for gluing something onto it,
do NOT sand right through the layer of glasscloth on the inside foam sandwich! It is only neces-
sary to rough up the surface, with 60/80 grit, and wipe off any dust with alcohol (or similar) before
gluing to make a perfect joint. It is very important to prepare the inside of the fuselage properly,
by roughing up and cleaning the surface, before gluing any parts to it.
Before starting construction it is a good idea to check inside the fuselage for any loose glass
fibres that could cut your hands, and a quick scuff over any of these with a coarse Scotchbrite
pad will remove them.
Landing Gear
The 1st job is to fit the landing gear legs and you
should leave these in place to protect the bottom
of the fuselage during the rest of the assembly.
The landing gear legs consist of 45° laminated
fiberglass and carbon cloth with a huge number of
carbon tows inside, all made in negative molds
and heat-cured. However it is still light weight, and
is flexible enough to take the shock of any land-
ings that are less-than-perfect!
The plywood support for the landing gear is already
factory-installed. Please double-check now that this
is properly glued in, and that the glasscloth rein-
forcement is well laminated to the area around it.
Both main legs are identical. Fit the landing gear in
place on the fuselage in the molded recess for it as
shown, and drill through 4 holes Ø 4mm for the M4
bolts and washers. Centres between each pair of
bolts should be approx 40mm (1.5”), and the outer
bolt position is already marked for you with a small
dimple in the leg.
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Remove the carbon legs and open up the holes in
the fuselage and ply supports to Ø 5.5mm. Refit the
legs with the washers and M4 bolts, and install the
T-nuts inside the fuselage. Secure the T-nuts to the
ply mount with a little 30 min epoxy.
Drill 4mm Ø thru’ the molded dimple in the bottom
of the carbon legs, and the mark in the inside face
of the wheelpant for the M4 x 45mm axle bolt. Drill
6mm Ø on the outside of the wheelpants, directly
opposite the axle hole, to insert the bolt. Don’t for-
get to make a ‘left’ and ‘right’ wheelpant !
Glue the small milled plywood part (20mm x 10mm)
inside the inner surface of each wheel pant, about
6mm above the 4mm Ø hole for the axle bolt. (see
drawing). This part is for the small sheetmetal
screw that holds the wheelpant at the correct angle
to the carbon leg. (see photo right)
Insert the wheels of your choice (65 - 75mm Ø) in
the wheelpant. The head of the bolt goes on the
outside of the wheel, inside the wheel pant. The
order of the items on the bolt is: Bolthead, washer,
wheel hub, washer, washers or wheel collars to
centre the wheel in the wheelpant, M4 nut, washer,
fibreglass wheelpant, carbon landing gear leg, and
finally another washer and the M4 locking nut. A
drop of Loctite before tightening the locknut is good
insurance.
To set the correct angle of the wheelpants in rela-
tion to the ground, set the fuselage on a level sur-
face and pack up the tail of the plane until the wing
is at about 0 degrees incidence to the ground. Eye
through both wheelpants so that they are
parallel and level, and secure with a Ø
2.9 x 13mm sheetmetal screw in each, as
shown, through the carbon leg into the
small plywood plate inside the wheel
pant.
C-ARF do not supply an optional tail-
wheel assembly for this Extra, but any
25mm/1” Ø lightweight wheel assembly
from a hobby store will do. You do not
need to make the tailwheel steerable
unless you fly from a hard runway - on
grass a simple fixed, or castoring action,
is fine. A 3mm plywood plate (15mm x
60mm) is already factory-installed in the
bottom of the fuselage in front of the fin
post to secure the tailwheel assembly to.
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Carbonfibre landing
gear leg 65 -70mm
Ø wheel
wheelpant
M4 bolthead
washer
washers/wheel collars
washer
washer
M4 locknut
M4 nut
milled ply
20 x 10mm
WHEELPANT X-Section

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Cockpit Canopy
A painted moulded fibreglass canopy frame and clear
cockpit canopy are provided in the kit. Fitting is quite
simple, as the canopy is quite small and rigid.
Complete all the canopy frame fixings before gluing in
the clear canopy.
There are several methods of securing the canopy
frame to the fuselage, and these depend on the type
and size of motor you will fit, and your own favourite
method. However, if installing a large single-cylinder
motor (eg: DA-50), then we highly recommend that
you fit the 2 plywood tongues at the back of the frame
- secured with two M3 bolts and T-nuts, as this is a
very rigid and rattle-free solution - instead of the single
hatch catch as this could vibrate ‘open’ in flight !
If fitting a glow engine, or electric motor, without too
much vibration then it should be OK to use the hatch
catch to secure the back of the canopy frame. Both
methods are shown below, and the hardware for both
methods is included in the kit.
For both methods the front of the canopy frame is
secured to the fuselage by a phenolic hook, installed
in a small milled plywood plate, and 2 or 4 small phe-
nolic tabs in the side rails to align the frame with the
fuselage exactly.
Lightly sand (or scrape with the edge of a sharp knife)
the joint seams on both the fuselage and the canopy
frame that could prevent it sitting perfectly flush, and
check the fit to the fuselage.
Sand under the front lip of the fuselage where the ply-
wood plate for the hook will be, and also inside the
front of the canopy frame. Using 30 minute epoxy, glue
the plywood plate into the fuselage, under the front lip,
with the slot aligned with the joint seam of the fuse-
lage, and the front of the slot 1 - 2mm back from the
edge of the fibreglass as shown in the photo.
Firmly tape the canopy frame into the exactly correct
position on the fuselage. Rough up the top of the phe-
nolic hook, and press it into the milled slot in the other
milled plywood part, and trial fit into the front of the
canopy frame to make sure that the hook engages
properly with the slot in the fuselage ply part. Adjust
height of the hook to achieve this, and then secure the
hook to the ply with a single drop of thin CA. Now glue
the complete plate into the front of the canopy frame
11

with a little thick CA. Finally glue the phenolic ‘U-
shaped’ plate under the slot in the fuselage ply plate
and use this to adjust the final canopy fit at the front.
Filing the slot at a slight angle to match the phenolic
hook gives the final fine adjustment to make sure the
front of the frame cannot lift up from the fuselage.
If fitting the 2 plywood tongues, instead of the hatch
catch, proceed as follows:
Fit the canopy frame to the fuselage, tape into position
accurately, and cut 2 slots thru’ the frame and fuse-
lage, 3.5mm wide x 20mm long, and with the outside
edge of the slots about 4mm from the outside of the
fuselage. The slots should be about 50 - 70mm from
the back of the cockpit.
Glue 2 of the milled ply squares (20 x 20mm) inside
the fuselage, exactly under the 2 slots, at 90 degrees
to the flanges around the cockpit opening, using a
thick mixture of 30 min. epoxy and micro-balloons, as
shown in the photo. You can taper these squares a bit
for a good fit against the angled fuselage sides.
Transfer the position of the holes in the milled plywood
tongues to the squares in the fuselage, and drill
through the fuselage sides and the ply squares Ø
3mm for the bolts.
Extend the length of the slots in the fuselage flanges
only, backwards, by 6 - 8 mm to allow the canopy to
slide backwards and disengage the front hook.
Carefully wax the area around the slots on both the
canopy frame and fuselage in case some epoxy gets
on there in the next steps.
Fit the M3 T-nuts into the holes in the milled plywood
tongues, and bolt them in position with M3 x 16mm
bolts, with the tabs projecting up through the slots in
the fuselage flanges.
Fit the canopy frame again, and tape firmly in position.
Glue the tongues into the canopy frame using a thick
mixture of 30 min. epoxy & microballoons. Cut off any
excess length above the canopy frame afterwards.
If you chose to fit the hatch-catch, then proceed as fol-
lows: Use one of the milled ply squares (20 x 20mm)
and file a half-round slot in the top of it for the catch.
Apply a little light oil to the mechanism of the hatch
catch to prevent it being glued together. Tack the catch
place on the plywood with CA, and then secure with a
good fillet of epoxy on both sides, as shown. Taper the
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Composite-ARF Extra 300L (2.12m/84”) [email protected]
edges of the plate if necessary for a good fit in the
fusleage.
Mill and file the slot on the fuselage centerline, behind
the canopy frame, for the handle of hatch catch. The
slot should be 2.5mm wide x 15mm long, and the front
of the slot about 20 - 22mm behind the front edge of
the fuselage moulding. Sand inside the fuselage in the
area where the catch will be glued later.
Without removing the canopy frame from the fuselage,
drill a Ø 3mm hole through the centre of the back of
the canopy frame and the fuselage for the hatch catch.
The centre of the hole should be 8 - 9mm down from
the top/outside surface of the fuselage.
Glue the hatch catch in position with 30 min. epoxy
and microballoons, with the 3mm pin projecting right
thru’ both holes into the canopy frame. Tape into posi-
tion until fully cured (with the fuselage upside down).
Add a short length of the fibreglass tape (supplied)
over the ply plate afterwards, using slow epoxy to fix it
to the fuselage. Fine adjustment of the align-
ment in the canopy frame can be achieved by
drilling a 3mm hole thru’ a small scrap of the
phenolic plate, and gluing it over the pin where it
projects inside the canopy frame afterwards.
(see photo above.)
Remove the frame, check the fit, and reinforce
all the joints properly with some 30 minute epoxy
and micro-balloon mixture.
To make sure that the sides of the canopy match
perfectly with the fuselage shape we recom-
mend that add 2 (or 4 if you fitted the hatch-catch) small phenolic tongues, as shown, and file
matching slots in the fuselage lip. We have included a some strips of phenolic plate (15mm x
50mm) for this purpose. With the canopy frame fixed in place with the hook and catch, and taped
in position at the sides, use a very small cutting wheel in a Dremel tool (or similar) to start to cut
the slots thru’ the canopy frame and fuselage together, which sets the alignment perfectly. Then
remove the frame and finish the slots with a small fine flat file. Glue the tabs into the fuselage,
not into the canopy frame, using 30 min. epoxy and microballoons. They should only project out
of the fuselage about 3 - 4mm, and the corners should be rounded to make it easy to fit and
remove the canopy frame.
Now glue in the clear canopy. Sand the inside edges of the canopy frame carefully with 80 - 120
grit sandpaper, especially the fibreglass joining tapes, to ensure a perfect fit of the canopy. Fit
the canopy frame on the fuselage and secure it. Lay the canopy on top of the frame, view from
the front to check that it is centred and symettrically positioned, and then mark the approx. shape
with a felt pen or wax crayon. Trim the canopy approximately to size so that it is about 6 mm big-
ger than the edges of the frame. When the canopy fits inside the frame, tape it into position tem-
porarily, check that it is aligned properly, and accurately mark the edge of the frame on the
canopy with a wax crayon. Remove the canopy and trim exactly to shape, leaving about 6mm
13

overlap outside the line all around. Unless you are in a warm room, we recommend that the
canopy is slightly warmed up with a hair dryer to prevent cracking - but be careful not to melt or
deform it!
With the canopy frame fitted to the fuselage, tack the canopy into position with a couple of very
small drops of ‘odourless’ CA, at the back lower corners and at the front centre also. You can
make some ‘handles’ from strong tape (see photo) to allow you to ‘pull’ the canopy in position
while you do this. When the canopy is tacked into the frame, and it cannot twist any more, you
can carefully remove the compete canopy frame and secure the inside edge of the clear canopy
with a small bead of 30 minute epoxy and microballoons. Alternatively you can use a specialist
canopy glue that dries clear and bonds well the the clear plastic. We have used the ZAP ‘Formula
560’ canopy glue with good success, and any drips of drops can be cleaned up with water before
it cures. Whichever method you chose, make sure to secure the canopy frame in it’s final posi-
tion on the fuselage while the glue dries to ensure that nothing can deform.
Cowling
Attaching the 1 piece cowling is easy, as it is
already cut and trimmed at the factory. We sug-
gest that you fit this now, and make any cutouts,
cooling and access slots after you fit the motor.
The cowl is secured to the fuselage with six M3
x 12mm bolts, and six T-nuts that are glued to
the inside of the horizontal flange on the fuse-
lage. Additionally you should add 2 small pheno-
lic tongues at the back lower corners of the fuse-
lage lip to maintain alignment, and prevent any
rubbing or damage due to vibration (see photo).
Fit these in the same way as for the canopy
frame.
Sand or scrape any seams on the fuselage and
cowling that might prevent it sitting perfectly
flush. File a notch in the back flange of the cowl-
ing to allow it to fit over the flange on the fuse-
lage. Sand the inside surface of the flanges on
the fuselage. Now carefully wax all around the
mating surfaces of the fuselage and cowling in
case you should get some glue on there during
the next steps.
Tape the cowling firmly into position on the fuse-
lage. Drill 6 holes of Ø 3mm through the cowling
and flanges of the fuselage as shown. Space the
holes about 65mm (2.5”) apart, and 6mm (1/4”)
from the edge of the cowling.
Apply some wax or thin oil to the M3 bolts and
push them into the 3mm holes. Reach thru’ the
front of the cowling and screw the T-nuts into
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Composite-ARF Extra 300L (2.12m/84”) [email protected]
position against the flange, with the flat side
against the flange. Apply one drop of thick CA to
each T-nut to hold in position, then remove the
cowl carefully and secure properly with some 30
min. epoxy and micro-balloons mixture. You can
grind or cut off the lower edges of the T-nuts that
project below the fuselage flange after the glue
has cured.
using epoxy, glue the 2 small phenolic tabs, as
mentioned above, at the lower back corners of
the fuselage and file matching slots in the cowl
to ensure correct alignment.
Note: If you have a flexible drive, or 90 degree
attachment for your Dremel then you can cut the
slots thru’ both the cowl and fuselage via the
cooling opening in the bottom of the cowl -
which ensures perfect alignment.
Horizontal Stabs
The stabs are 95% finished and the hinging is
already completed for you, using 4 large Robert
hinge-points in each elevator - so you only need
to install servos, horns and linkages.
The fibreglass tube inside the fuselage that
accepts the carbon stab spar, and the holes for
the anti-rotation pins are also jig-installed at the
factory, so the alignment and incidences are
already perfectly set. Double-check that the
6mm fiberglass anti-rotation pins are securely
glued into the root ribs.
Insert the 14mm Ø carbon spar in the fuselage
sleeve, and slide on both stabs. Check the fit
between the root ribs and fuselage, and if nec-
essary you can sand the roots of the stabs
slightly for a perfect fit. The carbon tube may
need to be shortened a little to 275mm long.
Servos: The elevators can travel more than 45
degrees, and if you are going to use the maxi-
mum throw for 3D manoeuvres, we strongly rec-
ommend hi-torque digital servos like
JR8511/8611 or Futaba S9351. It is not just that
15
5 - 6mm
152mm from
back of Fuse.

the torque of a standard servo is not enough - it
is the play in the gears which could cause prob-
lems centering, and might result in high speed
flutter.
IMPORTANT - Servo Output Discs:
We strongly recommend that you fit metal output
discs to all hi-power servos that will have the
phenolic servo arm extensions fitted to them,
and not the standard plastic discs - as shown
here. This is because the extreme torque of the
current digital hi-torque servos can, in some
cases, strip the splines from the plastic discs -
causing instant flutter ... and probable destruc-
tion of your plane.
The phenolic arms are tack glued to the metal
discs in the same way as described for the plas-
tic type, and then secured with a couple of small
(M2) bolts and nuts. Suitable metal output discs
are available from many companies, for exam-
ple the ‘Hanger 9’ type, part numbers:
#HAN3526 or 3520. (photo right)
This applies to the elevator, rudder and aileron
servos in this plane.
The elevator servos are installed in the fuselage,
due to the thin stab profile. Put some masking
tape on the fuselage and carefully mark and cut
out the 2 holes to the size for your servos. If
using a standard sized servo, like the
JR/Graupner 8511/8611, then the back of the
servo cutout holes should be 152mm (6”) from
the back of the fuselage, and the bottom edge 5-
6mm above the lower chine (angled corner) of
the fuselage. This position gives clearance for
the rudder pull-pull cables, which pass just
above the servo case.
Use the 3mm milled plywood reinforcing plates
to mark the holes accurately and file to shape
with a Permagrit file or similar. Rough up the
inside of the fuselage carefully, and glue the ply
plates in place inside with 30 min epoxy and
micro-balloons mixture (see photo above).
NB: Screw the servos into place with the Ø 2.9
x 13mm screws provided in the kit - not the standard screws that come with the servos.
The slots are already partly milled in the elevators for the horns, but you will need mill them deep-
er - to about 13mm (1/2”) depth so that the phenolic horn fits into the balsa block in the eleva-
tors right up to the small shoulders on the horn (see photo on page 21). It is important that both
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horns are in identical positions in rela-
tion to the hinge axis to give equal ele-
vator movements.
Put a layer of plastic parcel tape over
the area of one of the the milled slots,
wax it, and then cut through the tape
with a sharp knife to allow the horn to
be glued into the slots. This stops
excess glue getting on the surface of
the elevator. Adjust the slot in one ele-
vator so that the holes in the horn for
the clevise are exactly perpendicular
the elevator hinge axis, rough up the
gluing surface of the horn, and glue it
into the slot with 30min. epoxy and
microballoons.
When the glue has fully cured on the first horn, remove the tape, and make a horn alignment
template from thin plywood (see photo in wing section) and a 1.6mm drill or piece of wire, and
use it to install the horn in the other elevator. This ensures identical elevator throws.
Make up the extension leads for the 2 elevator servos, and centre both servos with your R/C.
Rough up the outer surface of two Ø 25mm metal servo output discs, and do the same on the
inner surface of two of the phenolic C-ARF servo arm extensions supplied. Glue the phenolic
arms to the discs with 30 minute epoxy and milled-fibre mixture, making sure that they are both
exactly at 90° to the bottom surface of the stabs. Remove the servos, and secure the phenolic
arms to the servo discs with 2 small bolts and nuts (M2 or equivalent) for each servo.
Make up the elevator linkages from the 60mm
long M3 threaded rods, with 2 clevises and 2 x
M3 nuts for each stab, as shown in the photos.
The clevise should be on the inner hole of the
servo extension arm, and on the elevator horn it
should be on the 3rd or 4th hole out from the ele-
vator surface - to maximise the mechanical
advantage and reduce any chance of flutter.
With your transmitter throws set at maximum
(125%) this will still allow even the hi-rate/3D
throws mentioned at the end of the manual.
‘Loctite’ the quick-link and loc-nut on one end of
each linkage. Add a couple of short lengths of
silicone tube over all clevises to prevent them
opening accidentally in flight. Do NOT use ball-
links on the servo arms or the control-surface
horns, because they will twist the servo
arm/horn and cause flutter. This is a solid expe-
rience and you should consider it a FACT.
The stabs are secured to the carbon tube using
two M3 bolts, screwed thru’ the bottom surface
of the stabs, into T-nuts that you must glue
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100mm
(above) Completed stab servo & linkage, also showing
the position of the M3 stab securing bolt, recessed
into the bottom of the stab. Note positions of clevises
on the horns for the maximum mechanical advantage.

inside the carbon tube. There is a small plywood reinforcing plate inside the stab that the bolts
will pass thru’, and the centre of this is 100mm from the root. Apply some masking tape to the
bottom of the stabs and mark the centre line of the stab tube on it. Fit the carbon tube into one
stab, and drill a Ø 2.4mm hole 100mm out from the root of the stab, thru’ the bottom surface, the
ply reinforcement, the fibreglass sleeve and the bottom of the carbon tube. Tap the hole M3.
Remove the carbon tube and glue in the M3 T-nut, using a thick mixture of 5 minute epoxy and
micro-balloons, with the M3 bolt temporarily in place to ensure alignment. Wax or oil the bolt first
!
Fit both stabs tightly to the fuselage, and then drill the hole in the other stab and spar tube, thread
and glue in the T-nut as before. Counterbore the holes in the bottom surface of the stabs for the
boltheads so that they fit almost flush with the bottom surface of the stabs, and put a piece of
clear tape over the bolt-heads for flight.
Note: Try to always leave the stab tube fixed in one stab, and never remove that one bolt, as it
is difficult to find the right position for the stab tube again if it is removed from both stabs!
Rudder
The rudder is hinged to the fin with a Ø 2mm
wire which passes thru’ the 3 phenolic hinge
posts that are factory-installed and aligned. File
a point on one end of the wire, and a short 90°
bend on the other end and push it through the
rudder from the top, capturing the 3 phenolic
hinges on the way. Don’t forget to secure the
bent end of the wire with clear tape for flight.
Trial fit the double-sided phenolic rudder horn in
the slot that is already milled in the base of the
rudder, and mark the part that will be glued in.
Remove it, mask the exposed parts and scuff
the centre part on both sides with coarse sand-
paper. Glue in place with slow (not 5 minute!)
epoxy and microballoons mix, making sure that
it is centred in the rudder. The front edge of the
phenolic horn should be flush against the back
of the balsa false leading-edge.
Servo: The rudder is a huge surface on the
Extra which definitely needs a hi-torque power
servo, and we recommend the digital
JR/Graupner 8511/8611, or Futaba S9351, for
this very important control surface.
The servo is mounted in a CNC milled compos-
ite balsa plate, with a milled 3mm plywood rein-
forcement glued underneath it, and 2
balsa/glass stiffening rails, in the fuselage under
the canopy area. The exact position you chose
is up to you, but position the mounting plate at
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least 86mm above the bottom of the fuselage to
make sure that the pull-pull cables will clear the
top of the stab servos.
NB: We recommend that this servo mount is
finally glued into the fuselage after completing
the motor and fuel tank base installation, form
easier access.
Glue the ply plate to the bottom of the balsa with
CA and mount the servo with the Ø 2.9 x 13mm
screws provided, not the standard ones that
come with the servo. The composite balsa rails
are glued into the milled slots under the front
and back of the plate with thin CA. Rough up the
fuselage sides before gluing the complete
assembly into place with 30 min. epoxy, and
then reinforce these important joints with the
glassfibre tape provided in the kit, and 24hr lam-
inating epoxy (see photo).
The milled balsa parts for the rudder mount are
a bit long, so you can chose the position to suit
your motor and sand them to length, and help to
set the correct Centre of Gravity. If you are using a lightweight set-up, like a glow engine, then
you should move the rudder servo mount as far forward as possible, so that the front of the plate
is against the back of the fuel tank mount. If you are using a larger motor, like the DA-50, you
can install it at the back of the cockpit area (as shown in the photo here) without CG problems.
Note: Fit the wings to the fuselage before gluing in the rudder servo mounting plate - so that you
cannot accidentally deform the fuselage.
With servo mounted under the cockpit as shown, the slots (30mm x 3mm) for the cable exits
need to be approx. 360mm (14.5”) from the back of the fin. If you prefer to ‘cross’ your pull-pull
cables inside the fuselage, then the exit slot positions will be above the stab servos and just
behind the leading edge of the stabs.
Rough sand the top surface of a 25mm (1”) Ø metal output disc, and the bottom of the phenolic
rudder servo arm. Centre the servo using your R/C and glue the phenolic horn in place perpen-
dicular to the servo, using 30 minute epoxy. Then remove the assembly and secure the pheno-
lic arm to the disc with the 3 small M2 bolts and nuts included, in a similar manner as for the stab
servo arm extensions.
Make up the pull-pull wires for the rudder from the hardware supplied, with a loop at the front
that goes over the hooks on the output arms, and a quick-link with turnbuckle and locknut at the
rudder end. For security pass the closed loop cable through the supplied ‘crimping tubes’ 2 times
before squashing flat with large pliers. Make sure that the wires are tight, and check and adjust
after the first few flights as the cables straighten out. Even a small amount of slop will prevent
your Extra from perfect tracking.
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Wings
The wings are 95% finished at the factory, and
have already been installed on your fuselage to
check alignment. They fit on a 30mm Ø alumini-
um alloy spar tube, with 6mm Ø fibreglass rod
anti-rotation pins at the front and back, which
are all completed for you. Each wing is secured
to the fuselage with a large M6 plastic nut, that
screws onto the bolt that is factory-installed in
the wing root. All you need to do is mount the
servos, glue in the aileron horns and make up
the linkages using the included hardware.
Please double-check now that the front and rear
anti-rotation pins, and the M6 plastic wing bolt,
are securely glued into the root ribs of the wings.
You can also check the inside structure of the
wings easily at this point, thru’ the cutouts in the
root ribs - to make sure that all critical compo-
nents are properly glued in position.
Glue the phenolic aileron horns into the milled
slots in the same way as the elevator horns,
making sure that the clevise holes are perpendi-
cular to the hinge axis. As before, we advise you
to fit just one horn first, then make a template
(see photo right) to ensure that the other horn is
positioned the same.
Servo choice: We highly recommend using a
hi-torque digital servo (eg: JR/Graupner
8511/8611 or Futaba S9351) for each aileron as
the surfaces are very large. We also strongly
recommend that you secure the phenolic servo
arm extensions to metal output discs on the ser-
vos, and not plastic discs. See page 16.
The servo hatches are pre-cut in the wing, and
supplied with matching servo covers and CNC
milled plywood servo mounts. Sand the inside
surface of the servo hatch covers and the milled
plywood parts that make up the servo mounts to
make sure you have a good gluing surface.
Assemble the servo mounts from the milled ply-
wood parts for each servo, using thin CA and a
90° square. Fix the servos into the mounts with
the Ø 2.9 x 13mm screws, and place them on
the hatch covers to check that the servo arms
are in the centre of the slots milled in the hatch
covers, and aligned with the aileron horns. Don’t
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