GRAUPNER DISCUS 2CT User manual

GRAUPNER GmbH & Co. KG D-73230 KIRCHHEIM/TECK GERMANY
Modifications reserved. No liability for printing errors. Id. No. 0062611 9/2011
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Order No. 4217.HOTT
OPERATING INSTRUCTIONS
DISCUS 2CT
Ready-to-fly RC model fitted with motor pylon,
three 850 mAh LiPo cells and HoTT receiving system
This model requires a HoTT COMPUTER SYSTEM

GRAUPNER GmbH & Co. KG D-73230 KIRCHHEIM/TECK GERMANY
Modifications reserved. No liability for printing errors. Id. No. 0062611 9/2011
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Please be sure to read through the safety notes in the Appendix to these operating instruc-
tions. If you ever dispose of the model, it is important to pass on the complete operating in-
structions to the new owner.
Introduction
The DISCUS 2CT is a semi-scale RC model aircraft which is capable of an
outstanding performance. The model can be converted in seconds from a pure
glider to a powered glider; all you need to do is fit or remove the motor pylon.
Please start by reading right through these operating instructions - before you
attempt to operate the model - and make yourself familiar with the method of
operating your HoTT transmitter. Keep the manual for your HoTT COMPUTER
SYSTEM to hand when preparing the model.
Pack contents
1. Fuselage, with factory-fitted motor pylon base and DES 231 rudder and elevator
servos, Graupner GR-12S HoTT receiver, PICO 8 speed controller, canopy with
snap-fit latch.
2. Wing with CFRP spar, decals applied
3. Tailplane and elevator horn, supplied loose
4. Factory-assembled motor pylon, complete with CAM PUSHPROP propeller
5. 3/850 LiPo battery, 11.1 V / 0.85 Ah, Order No. 7621.3BEC, with safety notes
6. 4217.HOTT operating instructions in German, English and French
7. Operating instructions for PICO 8 speed controller, various promotional brochures
Essential accessories (not included)
GRAUPNER HoTT COMPUTER SYSTEM transmitter min. MX 12 to MC 32
Transmitter battery charge lead Order No. 3022
Charge lead with BEC connector Order No. 3037
ULTRA TRIO PLUS 14 battery charger Order No. 6466
Essential adhesives (not included)
Cyano-acrylate glue (“cyano”), Order No. 5821, cyano activator, Order No. 953.150
Assembling the model
The model can very quickly be prepared for the air, but it is important to read and ob-
serve the following notes, as this will avoid problems, especially on the first flight.
Glue the tailplane to the fin, then connect the elevator horn to the pushrod and glue
the horn in the recess, as shown in the photo. Use cyano for these joints. This

GRAUPNER GmbH & Co. KG D-73230 KIRCHHEIM/TECK GERMANY
Modifications reserved. No liability for printing errors. Id. No. 0062611 9/2011
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procedure cannot be carried out at the factory for packaging reasons. Push the wing
into place and install the LiPo battery to complete the assembly stage.
The motor pylon
The motor pylon is a high-quality item which is supplied in the set ready to use. The
associated speed controller is set up as standard to suit the DISCUS 2CT; this
eliminates the need for any programming. Please note that the operating instructions
for the PICO 8 speed controller are supplied separately in the pack.
Binding the GR-12 receiver in the model to your HoTT transmitter
The “BINDING” procedure varies according to the HoTT COMPUTER SYSTEM you
are using; please observe the following notes, and the section entitled “Binding the
receiver” in the manual supplied with your radio control system.
1. Give the LiPo flight battery and the transmitter battery a full charge.
2. Locate the right-hand stick on your transmitter, and move it back towards you to
the “motor stop” position.
3. Now connect the BEC plug and socket between the speed controller and the LiPo
battery.
4. Initiate the “BINDING” procedure, and then carry out a full check of the working
systems. The servo leads should be connected to the receiver in the following
sequence: socket 1: speed controller; socket 2: rudder servo; socket 3: elevator
servo. This means that the throttle (motor control) and direction (rudder control)
are both assigned to the right-hand stick on the transmitter, and the elevator to
the left-hand stick. Pulling the elevator stick back towards you causes the elevator
to deflect up; moving it away from you causes it to deflect down.
5. If necessary, use your transmitter’s “Servo settings” menu to correct the direction
of rotation of the servos, and set the control surfaces exactly to centre (neutral
position). This is very important, otherwise the model will not fly straight, and will
constantly tend to climb or dive.
6. Now it is time to check the motor function by cautiously moving the right-hand
stick forward (away from you). It is always better to test the motor outdoors, and it
is very useful to have a friend to hold the model securely while you operate the
transmitter.

GRAUPNER GmbH & Co. KG D-73230 KIRCHHEIM/TECK GERMANY
Modifications reserved. No liability for printing errors. Id. No. 0062611 9/2011
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This photo shows the HoTT GR-12S receiver and the completed BEC connection
between the speed controller and the LiPo battery. The receiving system is switched
on and off by connecting and disconnecting the BEC plug and socket.
Control surface travels
We recommend the following maximum travels, in each case measured at the trailing
edge of the control surface: rudder 18 mm to either side of neutral, elevator 6 mm up
and down. The correct travels can be set at the transmitter; please refer to your HoTT
COMPUTER SYSTEM manual for information on this process.
Balancing
Assemble the model completely, ready to fly. The Centre of Gravity range is 62 to 72
mm aft of the wing root leading edge. Support the model at the stated CG position
with two fingers under the wing roots, and allow it to hang freely: the fuselage will
remain level when the model is balanced correctly.
Flying
If you are a beginner to this type of model flying, we recommend that you enlist an
experienced model pilot to help you check and test-fly the model.
Wait for a day with little or no breeze for the initial test-flight. The ideal flying site is a
flat grassy field with a gentle slope facing into wind. Never launch the model between
buildings or trees, as the air will be turbulent, making the aeroplane difficult to control.
The first flight should be a hand-glide, carried out with the motor pylon removed.
Simply “push” the model forward into the wind - don’t throw it. Trotting forward for a
few steps gains the necessary momentum. For hand-gliding the nose should be ang-
led down slightly (about 5°).
You will undoubtedly need to trim the model, especially after the first launch; fine-
tuning can be carried out by adjusting the trim buttons situated below and adjacent to
the transmitter sticks. When the model is gliding well, fit the motor pylon for a
powered flight. Again “push” the model into wind after trotting forward. However, the
fuselage nose should now be inclined up slightly (approximately 10°) for launching.
Always land the model directly into wind, with the motor switched off. Just before
touch-down, apply slight up-elevator to flare out and slow the machine down further.
Always land directly into wind.
All of us at GRAUPNER Modellbau wish you many fine flights with your new
DISCUS 2CT

GRAUPNER GmbH & Co. KG D-73230 KIRCHHEIM/TECK GERMANY
Modifications reserved. No liability for printing errors. Id. No. 0062611 9/2011
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Specification DISCUS 2CT
Wingspan approx. 1200 mm
Overall length approx. 750 mm
Wing section HQ 3.0/12
Tailplane section NACA 009
Wing area approx. 13.5 dm²
Tailplane area approx. 2.5 dm²
Total surface area approx. 16.0 dm²
Total area loading approx. 22 g/dm²
All-up weight approx. 340 to 410g
Environmental protection notes
The presence of this symbol on a product, in the user instructions or the packaging, means
that you must not dispose of that item in the ordinary domestic waste when the product
comes to the end of its useful life. The correct method of disposal is to take it to your local
collection point for recycling electrical and electronic equipment.
Individual markings indicate which materials can be recycled and re-used. You can make
an important contribution to the protection of our shared environment by re-using the
product, recycling the basic materials or re-processing redundant equipment in other ways.
Dry cells and rechargeable batteries must be removed from the device and taken separately to a
suitable battery disposal centre.
If you don’t know the location of your nearest disposal centre, please enquire at your local council
office.
Safety notes
Before you fly the model for the first time it is essential (and a legal requirement) to take out an
insurance policy designed to cover modelling risks.
Be sure to read right through the instructions covering assembly and operation of your model
before you attempt to operate it for the first time. You alone are responsible for the safe
operation of your radio-controlled model aeroplane. Young people should only be permitted to
build and fly this model under the instruction and supervision of an adult who is aware of the
hazards involved in flying an RC model aircraft.
In legal terms our models are classed as aircraft, and as such are subject to statutory
regulations and restrictions which must be observed. Our brochure “Modellflugrecht,
Paragrafen und mehr” (Model Aviation Law, Legal Requirements and more) is available under
Order No. 8034.02, and contains a summary of all these rules; your local model shop should
have a copy which you can read.
It is important to use only those parts included in the kit, together with other genuine Graupner
accessories and replacement parts as recommended expressly by us. Even if you change a
single component, you can no longer be sure that the whole system will work reliably, and
such changes also invalidate your guarantee.
Avoid short circuits and reverse polarity at all times.
The high energy density of rechargeable batteries involves a permanent risk of fire and even
explosion.
A radio-controlled model aircraft can only work properly and fulfil your expectations if it is built
very carefully, and in accordance with the building instructions. Nobody would climb into a
full-size sailplane and try to fly it without first completing a course of training. Model flying is
just such a skill, and has to be learned in exactly the same way.
However, as manufacturers we have no means of influencing the way you build and operate
your RC model aircraft, and for this reason we can do no more than point out the hazards
expressly. We accept no further liability.

GRAUPNER GmbH & Co. KG D-73230 KIRCHHEIM/TECK GERMANY
Modifications reserved. No liability for printing errors. Id. No. 0062611 9/2011
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If you need help, please enlist the aid of an experienced modeller, join a model club or enrol at
a model flying training school. Model shops and the specialist model press are also good
sources of information. The best course is always to join a club and fly at the approved model
flying site.
The operator of the model must be in full possession of his or her bodily and mental faculties.
As with car driving, flying a model aircraft under the influence of alcohol or drugs is highly
dangerous and not permissible under any circumstances.
Make sure that all passers-by and onlookers are aware of the hazards involved in the operation
of your model. Remind spectators to keep a safe distance from the model.
Always maintain a safe distance between your model and other people or objects. Never fly low
over people or directly towards them.
Radio-controlled models should only be flown in a temperature range of -5° to +35°C. More
extreme temperatures can lead to changes in battery capacity, material characteristics, the
strength of glued joints and other unwanted effects.
All model flyers should behave in a way which minimises the danger to people and property.
Never act in any manner which will disturb other pilots, or have an adverse effect on safe,
orderly flying at the site.
Don’t operate your model in the vicinity of high-tension overhead cables, industrial sites,
residential areas, public roads, school playgrounds, public parks or sports fields etc.
Pre-flight checks
Check that the radio control system works correctly before every flight: switch on the
transmitter and the receiving system, and check that all the control surfaces are at neutral,
work smoothly and immediately, and deflect in the correct “sense” in relation to the stick
movements.
If you are a beginner to this type of model flying, we recommend that you enlist an experienced
model pilot to help you check and test-fly the model.
Don’t ignore our warnings They refer to hazardous materials and processes which, if ignored,
can result in fatal injury or serious damage to property.
Propellers powered by a motor constitute a permanent hazard and represent a real risk of
injury. Don’t touch them with any part of your body. For example, a propeller spinning at high
speed can easily cut your finger badly.
Keep well clear of the rotational plane of the propeller. You never know when some part may
come loose and fly off at high speed, hitting you or anybody else in the vicinity. In un-
favourable circumstances this could result in serious injury. Ensure that the revolving pro-
peller never comes into contact with any object.
Make sure that it is impossible for any object to stall or block the propeller.
Every time you intend to operate your model, check carefully that it and everything attached to
it (e.g. propeller, tailplane etc.) is in good condition and undamaged. If you find a fault, do not
fly the model until you have corrected it.
Radio interference caused by unknown sources can occur at any time without warning. If this
should happen, your model will be uncontrollable and completely unpredictable. Never leave
your radio control system unguarded, as other people might pick it up and try to use it.
Do not switch the electric motor on unless you have checked that there is nothing in the
rotational plane of the propeller. Never attempt to stop the propeller when it is spinning.
Electric motors with propellers fitted must only be run when firmly mounted.
If you are to fly your model safely and avoid problems, it is essential that you are aware of its
position and attitude throughout each flight - so don’t let it fly too far away. If you detect a con-
trol problem or interference during a flight, immediately land the model to prevent a potential

GRAUPNER GmbH & Co. KG D-73230 KIRCHHEIM/TECK GERMANY
Modifications reserved. No liability for printing errors. Id. No. 0062611 9/2011
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accident. Model aeroplanes must always give way to full-size aircraft. Take-off and landing
strips should be kept free of people and other obstacles.
Your HoTT COMPUTER SYSTEM can only work reliably if the batteries are kept fully charged.
Never use hot, faulty or damaged batteries. Observe the instructions provided by the battery
manufacturer at all times.
Please don’t misunderstand the purpose of these notes. We only want to make you aware of
the many dangers and hazards which can arise if you lack knowledge and experience, or work
carelessly or irresponsibly. Provided that you take reasonable care, model flying is a highly
creative, instructive, enjoyable and relaxing pastime.
Manufacturer’s declaration:
If material defects or manufacturing faults should arise in a product distributed by us in the
Federal Republic of Germany and purchased by a consumer (§ 13 BGB), we, Graupner GmbH &
Co. KG, D-73230 Kirchheim/Teck, Germany, acknowledge the obligation to correct those
defects within the limitations described below.
The consumer is not entitled to exploit this manufacturer’s declaration if the failure in the
usability of the product is due to natural wear, use under competition conditions, incompetent
or improper use (including incorrect installation) or external influences.
This manufacturer’s declaration does not affect the consumer’s legal or contractual rights
regarding defects arising from the purchase contract between the consumer and the vendor
(dealer).
Extent of the guarantee
If a claim is made under guarantee, we undertake at our discretion to repair or replace the
defective goods. We will not consider supplementary claims, especially for reimbursement of
costs relating to the defect (e.g. installation / removal costs) and compensation for consequent
damages unless they are allowed by statute. This does not affect claims based on legal
regulations, especially according to product liability law.
Guarantee requirements
The purchaser is required to make the guarantee claim in writing, and must enclose original
proof of purchase (e.g. invoice, receipt, delivery note) and this guarantee card. The purchaser
must send the defective goods to us at his own cost, using the address stated above.
The purchaser should state the material defect or manufacturing fault, or the symptoms of the
fault, in as accurate a manner as possible, so that we can check if our guarantee obligation is
applicable.
The goods are transported from the consumer to us and from us to the consumer at the risk of
the consumer.
Duration of validity
This declaration only applies to claims made to us during the claim period as stated in this
declaration. The claim period is 24 months from the date of purchase of the product by the
consumer from a dealer in the Federal Republic of Germany (purchase date). If a defect arises
after the end of the claim period, or if the evidence or documents required according to this
declaration in order to make the claim valid are not presented until after this period, then the
consumer forfeits any rights or claims from this declaration.
Limitation by lapse of time
If we do not acknowledge the validity of a claim based on this declaration within the claim
period, all claims based on this declaration are barred by the statute of limitations after six
months from the time of implementation; however, this cannot occur before the end of the
claim period.
Applicable law
This declaration, and the claims, rights and obligations arising from it, are based exclusively
on the pertinent German Law, excluding the norms of international private law, and excluding
UN retail law.