Saturday, October 29, 2011

Aerial Photography: Maxi Joker 3

Minicopter, makers of the Joker 3

The Joker 3 is the latest model in a long line of field tested Joker helicopters. What began in 2000 with the Joker 1, the first high-end 90 class electric RC helicopter, has evolved over the years to become one of the most popular and universal models ever developed. The strength of the Joker in the beginning was it's enormous flexibility, whether as a beginner model, fitted to a scale fuselage, an aerobatic model, or simply a fun model to fly.

The Joker 3 complete with a basic aerial photo setup

Technology pushed things further, and with the advent of the first lipo batteries in 2004 there was a need to protect the very expensive batteries by creating a chassis that protects the valuable contents in the event of a crash. From this need the Joker 2 was born, primarily in the iteration of the Maxi-Joker. Because of its (smooth flying characteristics) and extremely low vibration it has become, and remains one of the world's most popular photo helicopter. As an aerobatic model, the Joker 2 was the first 12s battery powered helicopters.

The industry has shifted in recent years, the development of Flybarless electronics and falling prices of Lipo batteries coupled with an increase in reliability have brought many changes to the RC heli industry. Scale Heli flyers desired a drive shaft to be able to integrate the mechanics into lighter hulls. Aerobatic pilots wanted more maneuverability and less weight without compromising the chassis strength.

The Joker 3

It is precisely this basic idea of the expensive components of a helicopter in a compact, stable, and protective carbon chassis that has remained a design requirement. This typically yields around 200 grams more weight when compared to extreme lightweights on the market but costs from crashes are significantly reduced. The guiding principles of a joker are: low cost, low wear and long life.

Thus, all components of the joker are lovingly created in small batches with very tight tolerances. The same techniques are also used in the new model, the Joker 3. Concept The basic concept of the Joker 3 is to once again increase the quality. The Joker 3 in contrast to its predecessor gets a freewheel unit on the main rotor shaft and a split drive gear. Additionally the rigid tail rotor drive allows for a perfectly easy running gear, both in flight and autorotation. The freewheel on the Joker 3 is a 15mm(!) strong clamping body that allows for a total weight of up to 20kg. An additional feature is the main and tail rotor are decoupled from each other by a second freewheel, this led to increased smoothness on the 3DD and was carried over to the Joker 3.

The Joker 3 mechanics

"The very good and quiet running primary drive belt has carried over to the Joker 3. Of course the increased use of such a mechanism brought about increased manufacturing costs. A basic requirement of Joker kit must be that it costs less then 1000 euros, a requirement that they have stuck to to date. The solution to this problem was called value analysis. This is a process to optimize cost intensive production processes. A principle of our production was and is a mixture of self-manufacturing and suppliers of manufactured parts from precision oriented shops in Germany. Of course the lion's share has always been produced in house. Manufacturing process have been partially broken down to several companies and, above all, the in house manufacturing processes have been optimized. Thus it became possible to only incrementally increase the cost of the Joker even though commodity prices rose sharply in some instances."

So with the Joker 3 compared to the Joker 2 you get almost the same price for more helicopter. The good news is that the total weight of the Joker 3 is 200 grams lighter then Joker 2.

Features A fully kitted out Joker 3 aerial video unit Extremely stable and rigid chassisIntegrated host of Flybarless electronics in a well protected chassis.Compartments for components above the flight battery as well as optimum antenna position.Integrated battery slot for up to 12s/5000 mAh BatteryEngine mount acts as a cooling plate for the ESC, a small buffer battery can be mounted above the esc.Additional freewheel clutch between main-and tailrotor, an easy to mount and remove torque tube driveEasily removable tail boom for transportation and maintenance purposesPrecision scissor linkage on the tail rotor featuring 9 (!) bearingsPrecision swashplate with double ball raced swash holder and swash drive with 8 bearings.Direct CCPM linkages to the swashplate without the old push-pull linkages.Robust flybarless rotor damping with different hardnesses.Product family As the basic models we offer five alternatives: Joker 3 with belt driven tailrotorJoker 3 with TT driven tailrotorMaxi-Joker 3 with belt driven tailrotorMaxi-Joker 3 with TT driven tailrotorJoker 3 fuselage mechanic without main- and tail rotor and specific trainer attachments.

Particular emphasis was placed on the Joker 3 to give it the most flexibility possible. So in addition to the basic models you can also choose between the following alternatives:

Belt driven tail rotorMFS II main rotor instead of the paddle-less "V" rotor headBeginner Kit with specially tailored parts such as rotor blades, shorter tail boom, belt drive of the tail rotor and full upgradability to full-sized joker (8s-operation).Enlarged sub-chassie for enthusiasts of Li-ion or LiFe cells.Stabilizer or bracket for the rear strutsPlatform for gyro, or flybarless system that will not fit between the upper chassis plates.Technical data: Rotor diameter: up to 1.60 m (Maxi-Joker to 1.80 m)Weight without battery: 3250 gramsFor engines with 6mm or 8mm shaftTail rotor diameter: 290 mm (Maxi-Joker 330 mm)Reduction: Engine to main rotor: - depending on the Motor between 1:9 and 1:13,6 (7 levels)Main rotor to tail: - 4,8:1Recommendations for extreme performance Maximum: Engine: Kontronik Pyro or Köhler actro 32-3Control: Kontronik Jive 80HVLipo: SLS ZX 12s/3700 to 12s/5000 mAhBlades: Radix 690 or 710 mmTail Rotor Blades: Radix 105 mmFlybarlesselektronik: AC-3XServos: powerful digital servosReceiver: 2.4 GHz

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