Composite-ARF SuperXtra 330L User manual
Composite-ARF SuperXtra 330L (3.1m span)
Instruction Manual
Composite-ARF SuperXtra 330L, 3.1m
TAVS Technology version 2.0
Instructions for Extra 330L IMAC-Airplane
Thank you very much for purchasing our Composite-ARF Extra 330L all composite aircraft, made
with the revolutionary Total Area Vacuum Sandwich (TAVS) technology
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]
Telephone: Phone your C-ARF Rep!!! He will be there for you.
Website: http://www.composite-arf.com
This instruction manual aims to do 3 things:
1) Show you how to build your aircraft accurately and properly.
2) To explain about your fully-composite aircraft, and how to handle and maintain it.
3) How to set up and trim your finished IMAC type aircraft perfectly to give you the most enjoy-
ment from it.
Below are a few of the TOC pilots who helped to design and modify our 3m Extra 330S to the
championship-winning standard it is now at. And your 2.6m span Extra 330L is based on the
design of that plane and the experience of these experts.
2
Jason Shulman
Sebastiano Silvestri
Ivan Kristensen
Mike McConville
Composite-ARF
would like to thank all of
these 4 very experienced
pilots for their co-operation and
help, which has made this 330 Extra
aeroplane as good as it is today.
Of course all four of them are also Rep’s for
C-ARF, and if you want to ask them any questions
you can email them (see our website for links) directly,
or email your questions to us at ‘feedback@composite-
arf.com’ and we will forward your comments to them.
We are sure that they will answer you right away.
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.
Supplementary Safety Notes
Pre-flight checking:
Before every session check that all the model’s working 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. He
should be capable of detecting potential weak points and errors.
Be certain to keep to the recommended CG position and control surface travels. If adjustments
are required, carry them out before operating the model.
Be aware of any instructions and warnings of other manufacturers, whose product(s) you use to
fly this particular aircraft, especially engines and radio equipment.
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.
3
4
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 the
model 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 the accessories supplied in the kit.
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, before you start moving the CG back to a more critical
position for 3D-maneouvres. If you find that you need to relocate your batteries or even add
weight in the aircraft to move the CG to the recommended position, please do so and don’t try
to save weight or hassle. A tail heavy plane, in a first flight, can be an enormous danger for you
and all spectators. Fix any weights, and heavy items like batteries, very securely to the plane.
Make sure that the plane is secured properly
when you start up the engine. Have at least 2
helpers 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 first flight. It is
absolutely 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 you feel that the range with engine running is less then
with the engine off, please contact the radio supplier and the 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, so that any excess vibrations can affect
the servos and linkages.
Make sure that your main spars are not damaged. Check that the front and rear anti-rotation pins
for the wings and horizontal stabiliser are located correctly in their holes, and are not loose.
Check that the 4 plastic wing retaining nuts are tight, that the M3 bolts retaining the horizontal
stablisers on to the aluminium tube are installed and tight, and that the hinge wires for the rud-
der and elevators cannot come out.
If you carefully checked all the points above and followed our advice exactly, you will have a safe
and successful first flight - and many hours of pleasure with your Composite-ARF Extra 330L.
NO !!!
Secure the plane
before starting the engine.
DANGER ZONES
NO NO
General information about
fully-composite aircraft structure and design
All the parts are produced in negative molds, manufactured
using vacuum-bagged sandwich construction technology.
All parts are painted in the moulds, either single colour or
designer colour schemes. A new 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 as well. These
facts need to be explained in advance for your better under-
standing.
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 form a hard
and durable outer skin. Because of this TAVS technology
no additional structural parts are needed except for main
spars, which are the fully-floating, carbon reinforced type.
The ailerons are hinged already for you. They are laminat-
ed in the wing mould and are attached to the main wing
with a special nylon hinge-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 sur-
face, and there is a very narrow slot in the bottom surface,
where the aileron slides under the main wing skin during
down throw. This hinge setup is the cleanest you can ever
obtain, but you have to take some care during assembly for
proper installation and servo set up.
First, the hinge line is on the top surface of the wing, not in the centre. This is NOT a disadvan-
tage, if you set in about 10% NEGATIVE aileron differential in your transmitter program. 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 it travels, and the aileron gets a little "bigger" in surface area when moving up,
and "smaller" when moving down. This is why you have to set the negative differential in your
transmitter to compensate for the size changing. 10% is a good starting point, and you will find
out the exact setting during the first flights, doing fast vertical rolls and watching the fuselage
rolling in a perfect line. You can set it perfectly, this is guaranteed.
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
5
Centreline of hinge axis
Phenolic control horn
3.1m SuperXtra wing moulding,
showing full-carbon composite
spar and anti-rotation dowels.
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, as long as 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 wings are already set-up for 2 servos per aileron, and designed specifically around a pair of
JR/Graupner 8511/8611 servos which fit into a CNC-milled phenolic plate. For normal pattern
style flying, a pair of JR8411, or equivalent, servos should
be sufficient, but we highly recommend that you use the
suggested 8511/8611servos.
The wings are attached to the fuselage with the 4 threaded
aluminium dowel anti-rotation pins, with 4 plastic nuts
inside the fuselage. If the aluminium dowels come loose in
the wing, the wing will slide outwards, away from the fuse-
lage, and the main spars will definitely break. So take great
care to inspect the glue joints of these anti-rotation dowels
in the wing REGULARLY. Excessive vibrations or hard
shocks can cause the glue joints to weaken or break.
Monitor these joints whenever you set up your plane. Never
forget to tighten the nuts inside the fuselage. Your flight will
end after 100 ft and you will have to fix a hole in your club’s
runway. Please DO NOT modify these attachment dowels in
any way, their perfect function is proven for many years.
The Fuselage:
The fuselage is also made in negative moulds, and
(except for the bottom surface) it is also all constructed
using TAVS technology, with the diagon-technique carbon
strengthening for improved torsional stability. All the load-
bearing internal parts are glued in during manufacture, to
ensure accurate location and reduce the assembly time
for you. The pockets in the wings to receive the other ends
of the fully-floating blade spars, the stab spar tubes, and
the holes and reinforcement plates for the anti-rotation
dowels, are already installed. Although it is possible to
adjust the incidences of both the wings and the stabilisers
very easily using the C-ARF adjuster system, we have
already set these to the nominal zero position at the fac-
tory, which will be fine for 1st flights. See Wing and Stabiliser
sections for details, and the 2 photos here.
The landing gear mount is strong and doesn’t need any
extra reinforcement. You have an extremely light weight
fuselage, and the gear loads need to be led into the struc-
ture gently. No glue joint needs to be stronger than the
materials that it is attached to, as it would just result in
increased weight for no advantage. The landing gear is a
fairly flexible design, which works very much like shock
absorbers. This plane is not made for crashing, but the
landing gear will take some hard landings without prob-
lems. Do not change or modify it, as the results would only
be negative. We had plenty of time and experience to
engineer the strength needed in this area - and we did !
6
(above) The moulded incidence
adjusters are already set correctly
in the factory for your 1st flights.
(below) The stabiliser incidence is
also adjustable, but has also been
pre-set for neutral at the factory.
The whole fuselage is manufac-
tured using the ‘Diagon-techique’
with carbon tows to give excep-
tional torsional stiffness combined
with extremely low weight.
The motordome and firewall are pre-installed, and provide
plenty of strength for any engines up to 150cc on the mar-
ket today. See the Engine Installation section for details of
engine and setting thrust angles.
The engine cowling should be attached using the method
shown. It is only a little work and this mounting has been
tested and proven for many years.
The Stabilisers:
The stab parts are also vacuum bagged sandwiched. The
rudder and elevator control surfaces are hinged with 4mm Ø
tubes, fitted through phenolic hinge bearing plates which are
installed during manufacture for perfect alignment.
All the structural parts are pre-installed. The horizontal
stabs are mounted with one 20mm tube and one alumini-
um anti-rotation pin each. The rudder and elevator design
allows for at least 50 degrees throw. For the SuperXtra it
is necessary to keep the tail area as lightweight as possi-
ble, but it is still mandatory that each stab is fitted with two
powerful digital servos (JR8411 or 8511/8611) installed in
each half. Please remember during assembly of the plane
that every gram of weight should be saved in the tail area,
without omitting our recomendations about mass-balanc-
ing of the elevators.
Take Care:
Composite sandwich parts are extremely strong, but frag-
ile at the same time. Always keep in mind that these con-
test airplanes are designed for minimum weight and max-
imum 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.
7
(below) The SuperXtra is 99% pre-
fabricated, with all the bulkheads,
Rx and Powerbox plates, tank
base, rudder servo plates, etc.,
installed at the factory.
Some views inside the new factory,
showing a small part of the ‘Finishing’ and
the ‘Quality Control/Assembly’ areas.
The ‘Paint Job’
Occasionally customers notice certain problem areas with composite parts.
But the question is: Are these real problems, or are they just a misunderstood sign of high-tech
construction, proving the high-end composite technology?
Seams:
ALL composite parts have seams.
They are there today, and they will
be there forever. You will have to get
used to them ... or you’ll have to
touch up the paint yourself !
But what is a seam? A seam on the
fuselage, especially already painted
in the mould, proves that this is a
vacuum-bagged high-tech part,
made in negative moulds. Our
seams are fine and straight, no neg-
ative impression at all ... but they are
there. When possible we include
5mm wide strips of self-adhesive
vinyl, painted in exactly the same
colour as the plane for you to cover
the seams if you want.
Paint flaws:
If the aircraft is painted in the
moulds, you can save a lot of
weight. At least 2 lbs ... and that is
definitely worth saving !
A negative paint job is very compli-
cated to make. The painter never
sees the result of his job. He cannot
see the design growing and devel-
oping - he is painting ‘blind’. He
even cannot see little mistakes and
flaws, and even if he COULD, he
could not correct them. The maxi-
mum time to apply a designer paint
scheme in the mould is no more
than 20 minutes. It is a big rush
against time, because even if it is
just few minutes too slow then the
masking cannot be removed without
pulling off the paint itself ! This is a
BIG challenge, but the result is
extraordinarily impressive. Even
with slight flaws the general appear-
ance of these one-of-a-kind paint
jobs is unique.
8
(above) The 3.1m SuperXtra, 2.6m Extra 330L and the
2.3m Extra, are also available in the ‘JR scheme’.
(below) One of our customers with the original
3m Extra 330S practising his tail-in hovering !
In a ‘positive’ paint job some effects can
never be done. Just think about the
shadows, peel backs, highlights, and
3D effects - and all with a perfectly flat
and uniform surface for optimum airflow
and aerodynamics.
Truly hard to do, but still possible, are
the paint jobs which seem to be so sim-
ple at first glance: Schemes with
straight lines and stripes. Quite easy
with positive painting, but it’s very hard
masking the lines in the negative
moulds, because we cannot assemble
the parts before masking. To get the
stripes lining up exactly at the rudder,
wing and cowling joints is therefore
almost impossible. This is why we sug-
gest using thin vinyl trim to make sure
that these stripes line up perfectly.
Sometimes it is necessary to do that,
and it is definitely not a quality problem
or a "flaw". It comes back to what is
possible, and what is impossible.
If you want to have a really
perfect paint job, then you
might decide to have a sin-
gle colour version and have
it painted by yourself or
your friend.
But don’t forget: Consider
the additional cost, consid-
er the additional weight,
consider that even if it is
painted ‘positive’ there will
be areas you won’t be
happy with.
Of course you won’t com-
plain, because you created
these flaws yourself… !
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(above) The complex paintwork is completed in the
moulds by our skilled staff, to produce such stunning
schemes as this, all with a perfectly flat surface.
(below) This is the FiberClassics (now ‘Composite-
ARF’) force at the TOC 2000, with all models painted
in the moulds.
Tools and Adhesives
Tools etc:
This is a very quick and easy plane to build, not requiring difficult techniques or special equip-
ment, 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, 4mm & 5mm.
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. Small spirit level, or incidence meter.
10. Dremel tool (or Proxxon, or similar) with cutting discs, sanding tools and mills.
11. Sandpaper (various grits), or Permagrit sanding tools (high quality).
12. Carpet, bubble wrap or soft cloth to cover your work bench (most important !)
13. Car wax polish (clear)
14. Paper masking tape
15. Denaturised alcohol, or similar (for cleaning joints before gluing)
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. ZAP-O or PlastiZAP, odourless (for gluing in the clear canopy)
3. 5 minute-epoxy (highest quality seems to be Z-Poxy)
4. 30 minute epoxy (stressed joints must be glued with 30 min and NOT 5 min epoxy).
5. Epoxy laminating resin (12 - 24 hr cure) with hardener.
6. Milled glass fibre, for adding to slow epoxy for strong joints.
7. Microballoons, for adding to slow epoxy for lightweight filling.
At Composite-ARF we try our best to offer you a high quality kit, combined with outstanding
value-for-money, and as complete as possible. However, if you feel that some additional or dif-
ferent hardware should be included, please feel free to let us know.
10
Accessories
Here is a list of the things you may need to get your Composite-ARF Extra 330L in 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. 12 required). We recommend JR8511/8611’s for the ailerons, and
either JR/Graupner 8411 or 8511/8611 for the elevators and rudder.
2. Throttle servo (1) Any standard servo will do (eg: JR/Graupner 4041)
3. Aluminium Spinner 125 mm dia (5”), eg: Tru-Turn.
4. Main wheels 120 - 125 mm (4.5 - 5"). Kavan Light or Dubro wheels are recommended.
5. Engine DA-150. This is the recommended engine for your Extra 330L. The instructions
refer to that engine several times, but you could use any other 50cc engine.
6. Mini-Pipe Muffler Set. (Consists of 2 cannisters, 2 aluminium headers, 2 Teflon couplers,
4 spring clamps, and mounting hardware).
7. Standard exhaust muffler. (optional, if noise is not a problem at your field)
8. High quality heavy-duty servo extension cables, with gold connectors. High quality
receiver and ignition switches, ‘Y’ leads, ceramic/ferrite chokes etc.
9. Receiver battery. 2 x 2400 - 2800 mAH 5-cell packs recommended.
10. Ignition switch and battery for motor. 4 cell 1400 - 1800 mAH recommended.
11. Powerbox 40/24 and dual powerswitches for Rx batteries.
12. Fuel tank (1500 ml) with gasoline stopper. We used a Dubro S-50 in this model .
13. Cable ties in various lengths.
14. Propeller. Carbon 32 x 10 or 32 x 12 Meijzlik or Menz.
About the 3.1m SuperXtra
Building on the experience gained with our legendary 3m 330S Extra, we have designed the
‘Super’ to be the best flying plane in the skies. It has a fully-floating carbon blade spar, 20% larg-
er ailerons, bigger wing-span (3.1m/124”), stretched fuselage to allow 2 wing positions, reduced
rudder counter-balance to make the high-speed flight rock-stable, and the canopy is now the
larger ‘L’ version for improved knife-edge performance.
The level of prefabrication is carried to the limit. Canopy frame mounts, control horns, servo
mounts, fuel tank tray, muffler mounts, gear mounts, mounting plates for the receiver and power-
box, battery trays ... etc., etc, are all pre-assembled, aligned and checked at the factory before
shipping to you, ready for your hardware installation.
Did you read the warnings above, and understand the instructions completely?
Then, and only then, let’s start assembling your Composite-ARF Extra 330L.
If not, please read again before you start the assembly
11
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 wings and stabs can be
done at almost any point, and only need servos installing anyway, as we have already installed
all the control-surface horns for you at the factory.
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 of the fuselage 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 decals or markings. If you prefer you can cover the major-
ity of the fuselage with the bubble-plastic used to pack your model for shipping, fixed with paper
masking tape, which also protects it very well.
When sanding any areas of the inside of the fuselage to prepare the surface for gluing some-
thing onto it, do NOT sand right through the layer of glasscloth on the inside foam sandwich !
It is only necessary to rough up the surface, with 60/80 grit or equivalent, and wipe off any dust
with alcohol (or similar) before gluing to make a perfect joint.
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.
Note: 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.
Landing Gear Finished in 2 hours
The 1st job is to fit the landing gear legs and you can leave
these in place, as they will protect the bottom of the fuse-
lage during assembly. Wheel pants assembly can be done
later, but is shown here.
Composite-ARF developed a new carbon fibre landing gear
for the Extra. It consists of 45 deg laminated carbon fibre
cloth and a huge number of carbon tows inside, all made
under vacuum and heat-cured. However it is still light
weight, and retains enough flexibility to take the shock out
of any landings that are less-than-perfect!
To make it easy to replace or maintain the landing gear, the
undercarriage fixing bolts are installed from the outside,
bottom, of the fuselage, as shown in the photo here.
Mark the centreline on each landing gear, and drill 3 holes
with a sharp 6.5mm Ø drill as shown in the photo. The cen-
tres of the holes are measured from the bend in the leg that
will be flush with the outside of the fuselage.
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(above) The main legs are bolted
in place through the bottom of
the fuselage with 6 x M6 bolts.
The outer 2 holes are 33mm(1 5/16”) from the bend, and
the inner hole is 127mm (2 5/16”) from the bend. Note that
they are not equally position either side of the centreline.
The dimensions of 28mm and 8mm are measured from the
front of the carbon landing gear leg.
Fix the legs into the plane with the M6 x 20 bolts and 13mm
Ø washers into the blind nuts that are installed during man-
ufacture. Both main legs are identical, before you have
drilled the mounting holes, and can be used either side.
Fit the wheelpants to the legs as follows: Set the fuselage
on a level surface with the tailwheel in place. Pack the bot-
tom of the landing gear legs up by about half the diameter
of the wheels used (approx. 50mm/ 2”). Rough sand the
bottom of the carbon legs where the milled plywood parts
will be glued, to ensure a good bond. Fit the 2 plywood
pieces to the legs, using an M6 bolt and nut to hold loose-
ly in place. Hold the wheelpants against the milled plywood
pieces and adjust the angle of the plywood parts so that
they fit into the recesses in the moulded wheelpants, and
the bottom of the wheelpants are parallel to the ground and
each other. Tack glue the milled plywood parts to the bot-
tom of the legs with a drop of CA. Then glue the plywood
parts to the legs properly with slow epoxy and milled fibre.
To keep the wheelpants at exactly the correct angle and
flush against the milled plywood part that is glued to the
carbon leg, glue a small square (approx. 15mm x 15mm) of
scrap 3mm plywood inside the wheel pant 25mm above the
axle hole and glue an M3 blind nut to it. Then secure the
mainleg to the wheel pant by using an M3 bolt through the
leg. Do not use a bolt larger than M3, as the larger diame-
ter hole in the leg can weaken it.
The wheel axles are M6 x 70mm hardened steel bolts, fit-
ted through 6mm holes that you need to drill in the bottom
of the landing legs. Use the small dimple moulded into the
legs for the exact location. 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,
6mm wheel collar, M6 nut, washer, carbon landing gear leg,
and finally another washer and the locking nut.
You may need to adjust the thickness of the wheel collar, or
add a couple of extra washers to get the wheel exactly cen-
tred in the wheel pant. A drop of loctite on the M6 lock-nut
is good insurance.
It is just possible to assemble all the spacing washers on
the axle and wheel and squeeze it all into the wheelpant
carefully, but it is far easier to drill an 9mm (approx.3/8”) Ø
hole in the outside of the wheelpant (directly opposite the
13
(above) Shows scrap 3mm ply-
wood plate and M3 blindnut fitted
inside wheelpant.
(below) View of leg showing M3
bolt and M6 axle bolt with locknut.
(above) Milled plywood part glued
to carbon landing gear leg.
hole for the axle on the inner face) and
insert the axle bolt through this hole.
The order of fitting the wheelcollar, wash-
ers and wheel onto the axle, to centre
the wheel in the wheelpant, is shown in
the diagram here - but of course may
vary slightly depending on the size and
type of wheel used.
You can use any 4.5” - 5" main wheels.
Kavan wheels are very lightweight, but
not very durable on asphalt runways, and
Dubro wheels are a little heavier but
much more solid.
Any standard tailwheel assembly from a
good hobby store is suitable for your
Extra. The tail wheel setup shown in these photos is an
optional part available from C-ARF, and is mounted with 4
sheet metal screws and 2 plastic ‘U’ brackets under the
fuselage, screwed into the plywood reinforcement installed
in the fuselage at the factory.
You do not need to make the tailwheel steerable, a simple
castoring action is fine. However, for asphalt runways you
may prefer to connect it to the rudder horn with 2 springs as
shown. It’s easy to make these by winding some 0.8mm or
1.0mm Ø piano wire around a 5mm drill bit, turned slowly in
a battery-drill, with a small hook in each end to connect to
the tailwheel steering arms and the rudder horn.
Remember - keep it lightweight at the tail end!
14
(above/below) Optional tailwheel
assembly from Composite-ARF.
Carbonfibre landing
gear leg 120-125mm
Ø wheel
wheelpant
M6 bolthead
washer
6mm wheel
collar
washer
washer
M6 locknut
M6 nut
milled plywood
WHEELPANT X-Section
Cowling Finished in 2 hours
Attaching the 2 piece cowling is quite easy, as it is already
cut and trimmed at the factory, and should need almost no
adjustment for a perfect fit.
Sand the inside surface of both side (horizontal) flanges to
ensure a good gluing surface, and glue the 8 small pieces
(size 10 x 20mm) of 3mm milled plywood onto the flanges
of the bottom part of the cowling (4 each side), spaced
equally from the back to the front (see photos). The front
edge of the front piece should be 35mm (1.5”) from the
front of the cowl to clear the end of the mounting flange.
You can tack them in place with thick CA, and then rein-
force with 30 minute epoxy and microballoons mix.
Then take the bottom half and drill 3mm holes through the
dimple in either side, which match up with the dimple on the
fuselage, which also need to be drilled 3mm Ø. Do the
same by drilling the 2 holes in the back edges of the top half
of the cowling also, in the marks/dimples that are moulded
in. Temporarily bolt the bottom and top halves in place on
the fuselage with two M3 bolts and blind nuts on the inside
(inverted), and check for good fit. Tape the rest of the bot-
tom and top halves firmly in place, ensuring a flush fit with
the fuselage, and no gaps. If necessary you can sand the
inside back edges of both halves of the cowling to have a
perfect flush fit with the fuselage.
Now check the fit of the overlaps of the 2 halves of the
cowling, and sand the inside edges a little if needed for a
flush fit. When happy, tape together firmly and drill through
the joining flanges into the 8 plywood pieces, and secure
with 2.2mm ø x 10mm sheetmetal screws provided. The
holes for these small screws should be exactly 5mm from
the bottom edge of the top half of the cowling. The rearmost
2 screws will need to be shortened after fitting, otherwise
they will touch the motor dome. Just cut them off flush with
the inside of the plywood pieces.
The cowling is retained on the fuselage with 9 bolts M3 x
12mm and blind nuts. Drill one 3mm diameter hole at the
top/centreline of the cowl, approx. 10mm from the back
edge of the cowling, and insert an M3 x 12mm bolt and then
glue an M3 blind nut inside the fuselage with one drop of
thick CA glue. Don’t forget to rough up the area inside the
fuselage with coarse sandpaper first to ensure a good glue
bond. Note that the blind nuts are fitted reversed, with the
spikes pointing inwards! Check alignment again, and then
drill and fit the other 6 bolts in the same way, securing the
blind nuts to the inside of the fuselage with a single drop of
thick CA. Don’t forget to wax, or oil, the M3 bolts first, to
15
(above and below) Drill the
moulded-in marks in the fuselage
and both cowling halves and retain
with M3 bolts to ensure perfect
alignment.
make sure that you don’t accidentally glue any of the bolts
to the cowling or into the blind nuts! Space the bolts about
125mm (5”) apart, so that the lowest 2 bolts will be about
35mm from the edges off the square cutout in the bottom of
the cowling, which retains it properly.
Finally remove all the bolts and cowling, and glue the 9
blind nuts in place properly using a thick mixture of 30
minute epoxy and micro-balloons, as shown here.
Cockpit Canopy Finished in 1 hour
The canopy frame has already been fitted to the fuselage and the mounting has been done at
the factory for you. It is held in place with 4 bolts (m3 x 12mm) and all you may need to do is
‘counterbore’ the holes in the outside of the fuselage so that the heads of the fixing bolts are flush
with the outside surface (see photo).
Counterboring means making a larger hole for the bolthead
to go in, so it sits flush with the outside surface of the fuse-
lage, and the head sits against a flat surface inside the hole
- not an angled surface like that made with a normal coun-
tersink. The easiest way to do this is with a Dremel and a
small mill. Make the counterbored bored holes 6mm Ø and
about 5mm deep, so that the bolt head sits against the ply-
wood squares in the fuselage. Even better is to glue metal
washers into the holes for the bolts to sit flat against.
Note: This ‘counterboring’ technique also needs to be used
in the bottom surface of both horizontal stabs for the M3
bolts that hold them onto the 20mm aluminium tube.
Fitting the clear canopy into the frame is a little bit tricky, but
this is a step by step guide of how to do it successfully:
Sand the inside edges of the canopy frame carefully with
rough sandpaper, to ensure a perfect fit of the canopy
inside. Lay the canopy on top of the frame, and mark the
rough shape with a felt pen or wax crayon. Cut the outer
border of the clear canopy with sharp scissors, about
12mm (1/2”) too big all around. Unless you are in a very
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! When the canopy fits inside
16
(above) Counterbore the 4 holes
for the canopy frame bolts so that
the heads sit against the plywood
plates in the fuselage.
(above) The canopy frame is held
onto the fuselage with 4 plywood
tongues and M3 bolts/blind nuts.
Notice canopy finally glued in with
epoxy and microballoons mixture.
(above) M3 blind nuts, fitted
reversed, and fixed with thick
epoxy and micro-balloons mixture
inside the motor dome.
the frame roughly, mark the final cut line on it. Then cut it to
exact shape with a 6 - 8 mm overlap all around.
Make several hand-holds with wide paper masking tape
(see photo) to make holding and positioning the canopy
easy. Push the canopy up tightly inside the back of the
frame and fix the bottom 2 back corners with one drop of
slow CA each (ZAP-O or Plasti-ZAP recommended).
Note: Do NOT use any CA accelerator/kicker - you will
immediately ‘fog’ the clear canopy!
Tape the front of the canopy to the frame temporarily. Mount
the canopy frame to the fuselage (use all 4 bolts), and tape
the back of the canopy frame tightly to the fuselage. Using
the masking tape handles to pull the canopy outwards firmly against the frame, working from the
back towards the front, glue the edges of the canopy in place in 2 more places each side, with
just a single small drop of CA at each position, all the time checking that the edge of the canopy
is tight up against the frame at the front.
Then make visual check from the front and back to make sure sure that the canopy is straight.
Now that the canopy is fixed in position and cannot twist or warp anymore, you can carefully glue
the rest of the canopy firmly in place. You can either complete the gluing from the outside, allow-
ing the CA glue to wick into the joint between the frame and the clear plastic or, if you prefer, you
can carefully remove the canopy frame from the fuselage, and use a 30 minute or 24hr epoxy
and micro-balloon mixture for gluing all the edges to the frame on the inside surface. Even if you
use the CA glue method, we recommend that you also glue the inside edges with the the epoxy
mixture to be sure that the canopy cannot come off in flight.
If you wish you can tint the inside of the canopy using one of the aerosol spray paints used for
painting the inside of polycarbonate car bodies (eg: the Tamiya or Lexanit ranges). Use many
very light coats to get even coverage.
Horizontal Stabs Finished in 2 - 3 hours
The stabs are 99% finished at the factory, and only need the 4 servos, outer elevator horns and
linkages installing. We have already installed the inner control surface horns for you, but it is
mandatory to fit 2 servos in each stab, to prevent any chance of flutter, and so you need to install
the outer control surface horns for the outer servos in each elevator half. Follow the instructions
below for fitting the outer horns into the elevators.
First insert the 20mm aluminium tube spar in the fuselage sleeve, and install both stabs to check
the fit between the root ribs and the fuselage. You might
have to sand the root of the stabs slightly to make a perfect
joint, and if the tube is too long can to shorten it a little.
You have a choice of servos for the elevators, either a pair
of the hi-power digital JR8511/8611’s in each stab, or a pair
of JR8411’s, which is also sufficient for each elevator.
Important Note: C-ARF also strongly advise that you
partly static-balance the elevators by gluing 25 -30 grams
17
(above) The canopy is glued in
place with CA, using masking-tape
handles to pull it into place.
(3/4 - 1 ounce) of lead in the leading edge of the outer
mass-balance area in each elevator half, which helps to
prevent any chance of flutter that could destroy your Xtra.
(see photo on page 19)
Although the JR8511/8611 servos are about 1 mm longer
and wider than the 8411 type, you will find that both sizes
will fit in the milled servo cutouts in the rib without problems.
The elevators are hinged to each stab using the 4mm Ø
aluminium tubes provided. Make sure there is no burr on
the end of the tube, and you can chamfer the end slightly
with fine sandpaper to make it easier to get them through the
holes in the phenolic hinge plates. Be careful inserting them,
and if they are a bit stiff, then use a little grease on the tubes.
Don’t use too much force, otherwise some of the phenolic
plates inside might break loose. Leave the tubes a bit too
long during construction, and cut them to exact length when
the model is finished. During final assembly, retain both
ends of the tubes with a small piece of clear tape on the
root and tip ends of the elevators.
NB: To fit the dual servos in each stab you must fit the outer
(tip) servo first, using a long (30cms/12”) screwdriver,
inserted through the inner servo hole in the root rib to tight-
en the bolt that holds the servo arm onto the servo shaft.
To fit the outer servo, proceed as follows: Mill out a slot in
the fibreglass tip of the stab., as shown, to allow the servo
to fit in the milled hole in the rib that is already built in dur-
ing manufacture. Note that the servo is fitted inverted, with
the servo shaft nearest to the leading edge of the stab. You
will need to drill a hole of about 6mm (1/4”) in front to get
the screwdriver though to tighten the front servo screws.
Use the 2.9mm Ø x 13mm screws provided in the kit, not
the standard screws provided with the servos. You can
cover these holes in the tip of the stabiliser moulding with
pieces of self-adhesive film afterwards if you wish. You may
need to grind 1mm or so off the inner end of the phenolic
hinge plate that projects inside the false trailing edge of the
stab for enough clearance to install the servo.
Mark and mill out the slot in the bottom of the stab for the
servo arm. The slot should be approx. 4mm wide and 55mm
long, and the back of the slot should be about 50mm from
the trailing edge of the stab. If using JR8411 servos and C-
ARF servo arms, then the centre of the slot should be
exactly 16mm inside the servo rib, which can be seen in the
false trailing edge. In any case, start the slot a bit smaller
than this, and enlarge until correct.
At this point you should fit the elevator to the stab, and
make the control surface horn alignment template from a
18
(above) The outer servo is fitted
into the stab inverted, against the
factory-fitted rib. Note the hole in
the tip leading edge for access to
the servo securing screws.
(above) Cut the slot for the C-ARF
servo output arm.
(below) Horn template for outer
horns is made using the inner ele-
vator horns for identical throws.
(above) Completed stabiliser and
linkages showing the mandatory 2
servo set-up, also showing the
20mm Ø stab spar tube and anti-
rotation pin.
piece of thin scrap plywood as shown here. Make the tem-
plate to fit the inner horns, which are already installed at the
factory, and drill a 3mm hole in the plywood that exactly
lines up with the 3mm holes in the double horns. Check that
it’s correct by putting an M3 bolt through the horns and the
template. Notice the small ‘hook’ at the back of the template
to set the position from the trailing edge of the stab.
The elevator is 3mm thinner at the position of the outer
servo than the inner servo and (as it is centre-hinged) so
the horns must project out of the elevator 1.5mm more for
the outer servo than for the inner/root servo. This important
to get the same throws from each servo, and prevent them
working against each other, and possibly stalling, causing a
big current drain on your batteries. Therefore, glue a small
scrap of 1.5mm thick ply or balsa to the bottom of the tem-
plate and use it to set the position of the outer horns while
you glue them in place.
Now mark the position of the slots on the elevator for the
outer control surface horns. Mill the slots with a dremel until
the horns fit properly and can be temporarily joined with
one of the ball-links provided and an M3 bolt though the
horn alignment template as shown. Put a layer of masking,
or clear, tape over the area of the milled slot, wax it careful-
ly, and then cut through the tape with a very sharp knife to
allow the horns to be glued into the slots. This stops the
glue getting on the surface of the elevator. Scuff up both
sides of the phenolic horns with coarse (60 grit) sandpaper
or a Permagrit tool to ensure a good glue bond, and glue
them in with slow epoxy (minimum 1hr cure) mixed with
milled fibreglass, or a filled thixotropic epoxy (eg:
Loctite/Hysol 9462 or BVM Aeropoxy). Check that horn is at
90° to the surface of the elevator, and wipe excess glue off
before it cures.
Important Note: The C-ARF phenolic servo arms supplied
with the kit have to be attached to the servo output discs,
but if using the 8511/8611 servos it is mandatory to use
metal (aluminium) servo output discs for this - and not the
standard plastic output discs supplied with the servos, as
the extreme torque of these digital servos can strip the
plastic splines from the inside of the disc - which will result
in immediate flutter and destruction of your SuperXtra.
We also highly recommend that you also use aluminium
output discs when using the JR8411 servos, or other simi-
lar hi-torque digital servos. Several reputable after-market
accessory companies make suitable aluminium discs, but
you must check that the CNC machined splines fit the servo
output shaft tightly, with a minimum of play. Fit the discs to
the servos and use a little Loctite on the retaining bolt in the
centres. Centre all 4 elevator servos using your R/C and
19
(above) Slots cut in elevator for
outer dual control surface horns.
(below) Add 1.5mm scrap ply to
the bottom of the horn alignment
template for correct positioning of
outer elevator horns.
(above) We strongly recommend
that you partly mass-balance the
elevators with 25-30grams lead in
each as shown here.
(below) You must use aluminium
discs on the servos, especially if
using the 8511/9611 servos, fixed
to the C-ARF phenolic sservo arms
with at least 2 bolts each.
attach the phenolic servo arms to the outside of the metal
discs temporarily with a couple of drops of CA, making sure
that the servo arms are at exactly 90° to the bottom surface
of the stabs using a set square. Then remove the arms and
discs, drill through both, and secure with at least 2 small
bolts, washers and locknuts (M2 or equivalent size).
Make up the linkages from the hardware supplied, using
M3 threaded rods (90mm for inner servos, 65mm for outer
servos), with a quick-link and M3 nut at the servo-end, and
a ball-link in between the double horns secured with an M3
bolt and locknut. Add short pieces of Tygon fuel tube, or
similar, to make sure the quick-links cannot open in flight !
The last job is to fit the M3 stab retaining bolts and blind
nuts. Look inside the stabs and you will see the small ply-
wood reinforcement plates between the spar sleeve and
the bottom surface of the stab. Mark the bottom of both
stabs in the centre of this plywood. Install the aluminium
tube into 1 stab, and drill a 2.4mm hole right through the
stab surface, the plywood plate, sleeve and into the 20mm
aluminium tube. The centre of the hole should be about
34mm from the trailing edge of the stab. Thread the hole
with an M3 tap and secure it with an M3 x 16 bolt. To be
really secure, you can glue an M3 blind nut inside the stab
spar tube, as shown here, with some 30 minute epoxy and
micro-balloons. Wax or oil the bolt first!
Fit both stabs to the fuselage, check that they fit tightly to the fuselage at the roots, and then drill
the hole in the other stab and spar tube, thread as before, and secure with another bolt.
Counterbore the holes in the bottom surface of the stabs for the boltheads so that they fit flush
(see canopy frame section).
As mentioned earlier, the stabiliser incidence is adjustable, using a ball-wrench though the holes
in the bottom of the fuselage, but it has been pre-set at ‘neutral’ at the factory and should not
need adjusting.
Note: Try to always leave the stab tube fixed in one stab, and never remove that one bolt, as it
is very difficult to find the right position for the stab tube again if it is removed from both stabs!
Rudder Finished in 2 hours
Fit the rudder to the vertical stabiliser with the 4mm Ø brass
tube supplied, in the same way as the elevators. Check for
smooth movement. The dual phenolic rudder horns are
already glued in place at the factory during manufacture.
The rudder is a huge surface on the Extra 330L and the
choice of servo is up to you. For pattern flying 4 hi-torque
servos (eg: JR4421) would probably be sufficient, but if you
plan to fly 3D or radical freestyle we highly recommend
20
(above) The completed inner ele-
vator linkage. You can also see the
head of the M3 retaining bolt, with
the bolt head counterbored flush
into the surface of the stab.
(below) M3 blind nut glued inside
the stab spar tube with 30 minute
epoxy and micro-balloons mix.
(above) Pass rudder cable thru’
crimping tubes 2 times for safety.
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