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The proven MFS
(moving flybar system) rotor head is transferred from the Rocket
to the Three Dee NT with only two minor changes, the paddles are
lighter and the flybar is longer to achieve greater manoeuvrability.
3D pilots will find it easier to fly this helicopter, because
of the reduced cyclic inertia and the light weight of only 4.3kg
all up.
The proven MFS
(moving flybar system) rotor head is transferred from the Rocket
to the Three Dee NT with only two minor changes, the paddles are
lighter and the flybar is longer to achieve greater manoeuvrability.
3D pilots will find it easier to fly this helicopter, because
of the reduced cyclic inertia and the light weight of only 4.3kg
all up.
On the MFS (moving
fly bar system) rotor head system the complete pitch compensator
is no longer used. To obtain collective pitch movement, a sliding
fly bar system is used. This construction has got the following
advantages. The required lift, that the swash plate needs to produce
the collective Pitch range, is halved compared to traditional
systems.The bell-hiller levers, which are fixed on the pitch arms
remain horizontal throughout the pitch range. This feature has
the advantage that asymmetric blade pitch doesn't occur during
cylic inputs, because with MFS, the mixing levers are only making
small movements. It is clear, that the pitch loads are greater,
therefore there are advantages to using a three servos CCPM system
compared with mechanical pitch control, which only uses one servo.
The advantage of MFS is to obtain a large pitch range, without
excessively long servo arms, as found with normal CCPM. The halved
swash plate stroke makes it possible to use less servo movement
found at extreme stick positions. To make this possible it is
important to use high quality servos with high power and little
slop. With CCPM you can reduce the percentage of pitch movement
in TX set up, but for the elevator and aileron the full percentage
is maintained. This will avoid the large ineffective servo movements
found at high pitch angles with large cyclic deflections. To fully
use this advantage the Three-Dee NT is equipped with a Push-Pull
bell crank cyclic system.
 The
80mm diameter precision machined Aluminium cooling fan with the
same blade geometry as the Rocket, is fully capable of cooling
the higher temperatures generated by 15 cc engines. The model
is designed to run zero Nitro fuel with no problems, even on hot
summer days. The hardened rotor shaft is only 131mm long making
this the shortest and strongest in its class. The canopy is very
similar to the Rocket canopy with the addition of small bulges
to clear the large drive pulley. This fully aerodynamic design
completely encloses the mechanics allowing for a low coefficient
of drag during high speed flight.
During the design process I followed my
philosophy of creating everything to the highest quality standards
while keeping the design simple using as few parts as possible
to maintain the highest accessibility, ease of maintenance and
reliability. The in-depth handbook and clear instructions should
make assembly easy. Through the practical combination of design
and experience with the Three-Dee and the Rocket, a new strong
and durable all rounder has been created that is very flexible
and will cope with all the demands of different Pilots. From hovering
to extreme 3D flying and high speed flight, this helicopter does
it all.
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• The Henseleit
Three-Dee NT Helicopter combines extreme manoeuvrability
and speed together with rapid climb rate within a wide range
of rpm and low noise levels.
• The Three-Dee NT can fly between 1200 and 2000 rpm
with no loss of performance and extremely low noise levels.
• The Three-Dee NT is designed around the OS 91 and
at only 4.3 kg all up the performance is stunning on straight
fuel.
• Light and strong CFK / Aluminium construction of
highest quality.
• Designed with maintenance friendly construction with
no unnecessary components.
• Skid plates with fast fixing system, designed to
release in most crash situations reducing air frame damage.
• Aluminium high performance cooling fan / flywheel
as a standard.
• Patented MFS (moving fly bar system) rotor head with
sliding flybar does not need pitch compensator, which in
turn gives an extremely short distance between upper main
bearing and centre hub, MFS halves the pitch movement required
without changing the bell-hiller levers (ideal for a 120°
CCPM setup).
• Easily accessible engine, that can be removed and
replaced in minutes.
• RC-system protected within the side frames.
• The Three-Dee NT has an extremely low centre of gravity
due to its compact design this greatly improves cyclic performance
and control response over the full flight envelope.
• Proven high performance belt drive system for main
reduction and tail drive gives simple yet robust set up
and high relability with low maintenance.
• Full aerodynamic canopy encloses the complete mechanics
allowing for a low coefficient of drag during high speed
flight.
• Engine: OS 91 FX - HGL
• Main rotor reduction: 9 : 1 / 8,3 : 1 / 7,7 : 1 (standard
for the OS 91) / 7,2 : 1
• Tail rotor reduction: 1 : 4,92
• Recommended rotor rpm.: 1200 - 2000 rpm
• Recommended fuel: straight fuel with 12% oil
• System: cw and ccw is possible with different crankshaft
for the OS and mirror image cooling fan / flywheel
• Tank: 500 cc (14 - 20 min)
• Rotor diameter: Main rotor: 1540-1600 mm, Tail rotor:
270 mm
• Trunk length / height: 1430 mm / 360 mm
• All - up weight without fuel: 4300 g !!!
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 I
have the advantage of flying and testing my own helicopter designs
and therefore can give good advice and tips for equipping and
tuning the Three-Dee NT. This has proved to be very useful in
the last few years. Time and again pilots have confirmed that
following my advice and recommendations has lead straight to success.
Though pilots have their own specialised techniques for the helicopter
set up, small changes can make all the difference to the flight
characteristics of the model, however you will save yourself a
lot of time, and can enjoy flying right from the beginning if
you follow my recommendations. I will be, of course, grateful
to hear of your experiences and suggestions for improvements at
any time.
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Engine: OS MAX 91FX-HGL
R.C.Models Part-No. 3D 91R
OS MAX 91FX-HGL
R.C.Models Part-No. 3D 91L
Tuned pipe: Hatori 700
NT - manifold: set for OS Engine
Henseleit Part-No. NT-0980
Glowplug: ENYA 4
Lötterle carb: (definitely necessary)
RSV 10/2000 Henseleit Part-No. NT-0362/RSV
Starter adaptor: Henseleit Part-No. NT-0399R, Henseleit
Part-No. NT-0399L
RC - installation: For swash plate control you will need
powerful, robust and precise servos. I strongly recommend
the following!
Swash Plate Servos: Futaba S 9206 (times 3) No other servo
is recommended. This servo puts out 9,5 kg/cm only with
4,8 Volts. It is not digital and therefore require less
current. Digital servos are not recommended, as the power
consumption is considerably higher.
Throttle servo: Any high quality standard servo
Tail servo: Futaba S 9253 or a servo recommended for Gyro
used.
Gyro: CSM SL 560 / Futaba GY 401 or equivalent high quality
gyro.
Receiver: PCM- Receiver
Receiver nicad: Sanyo 1700 mAh Ripmax No 4K1700 AUSF. No
JR equivalent. Approx size. 67 x51 x17 (135 g) bigger nicads
are not necessary and take up too much space.
Main Rotor Blades: NHP Razor Pro Blades 710mm / 185g
Tail Rotor Blades: K&S 95mm / 5g Henseleit Part-No NT-0309
Fuel: about 12% oil / no nitro!
Attention: Do not use paddles weighing more then
40g on the Three-Dee NT!
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