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Original Year
1995
# of pieces
1063
Categories
Aircraft: Helicopters
Other: Universal Sets
Other: Other
Dimensions
various
Models
(Control Center)
Helicopter
Dinosaur
Boat

8485 Control Center II

8485 revolve
revolve

Though not technically labeled as a Universal Set, the 1995 set 8485 easily holds the title of the best one (with the possible exception of 8479 which is also not technically a Universal Set).  It is based around a Control Center programmable electronic battery box nearly identical to that first found in 8094 with a very notable exception.  Although typically called "Control Center II" by fans due to its obvious succession of 8094, it is actually not labeled as such.  Like its predecessor, this is one of my favorite of all Technic sets, and should be the near the top of any collector's acquisition list, but be prepared to pay dearly for it.

This massive set is annoyingly difficult to acquire in the United States.  It is a massive set with over 1,000 parts and was among the very biggest Technic sets ever until the new millennium repeatedly broke that mark.  The set also includes 3 of the high speed 9V motors, a pile of nice long (and rare) flex system parts, 6 electric cables, an AC/DC transformer (for powering from household electricity), 14 silicone belts, and 18 beams of 16L length!  This set marks the first time that a significant number of parts have been used for the "stand" to support and control a model as opposed to simply creating the model itself.

Each and every model is a work of art, with the first two in particular breaking new ground that has scarcely, if ever, been matched.  The helicopter serves as a flight simulator with elevation, pitch, roll, and rotating rotors all under the pilot's control.  The dinosaur features incredibly life-like (I guess I can't actually prove this) motion including arms, tail, neck, jaw, and legs which move.  The final model, and air boat, while not as large or impressive as the others, is an excellent model in its own right.  It drives, steers, and spins the fan.

After first acquiring this set, I agonized for years over which model to display, the dinosaur or the helicopter.  After reaching a state of acceptance that a choice would never be made, I solved the problem by getting a second copy and displaying both models.

Control Center
Control Center
The Control Center is the heart of this set.  It was the first programmable power system for LEGO® motors.  There is a battery compartment on the bottom which holds 6 C sized batteries (LR14) in series, producing a total of 9 volts DC.  This particular unit is nearly identical to that found in 8094 except that the buttons are a different color and it has an input for a transformer!  This allows it to be powered from a wall plug instead of using up dozens of batteries.

The Control Center has 3 color coded power outputs, each capable of driving a 9V motor.  The red output is labeled "A-B" and is controlled by the two red buttons on the left with the same labels.  One buttons drives one direction, and the other reverses polarity and drives the motor the other way.  The yellow outputs are labeled "N-S" and "E-W".  They are controlled by a 4 way control pad on the right.  Movement of the control pad in a diagonal direction effectively controls 2 channels at once.

The gray buttons in the center control programming.  There are two memory sections which the Control Center can toggle between.  Once a memory is selected, you can push Program and the system will record your inputs, including duration, and including pauses.  When you are done recording the program, you push Stop and it is stored to memory, even if the unit is switched off.  You can then play it back (Go) at any time, or you can control the system manually.

There is obviously some limit to the amount of memory on the system so it can only record a certain number of inputs, however, I have never found the limit.
control center
1st Model:  Helicopter
This marvelous helicopter is nearly the best ever produced in the Technic line with the possible exception of 8856.  Its list of functions is large (and so is the model), but what really makes it stand apart is the way that it can actually be "flown" like a flight simulator.

The 3 motors are integrated such that they can hardly be noticed, and even the wiring tucks away and is bundled with a rare set of silicone helical loops (seen in some of the photos in white).
1    render
Click to download the LDraw file of this model.
Model by Benjamin Wendl

Click for an animation of the helicopter in motion.
Elevation
The mechanism for controlling elevation of this helicopted is ingenious.  The Control Center is actually used as a counterweight which acts against the helicopter via a pair of 4-bar linkages.  Depression of the Control Center raises the helicopter.  The weight and lever arm are accurate enough a counterbalance (with the addition of internal friction) that the helicopter stays up.  When the Control Center is lifted, the helicopter descends into a gentle landing on the attached landing pad.  The landing pad is static and remains at the same level.  Note that batteries must be installed in the Control Center (even if you are not using them) to get the balance right.

The mechanism to control the elevation is rather complex and is pictured at right.  In consists of a pair of nested 4-bar linkages which are linked via a central connection.

The outer linkage is made from mostly black beams and supports the Control Center.  The computer image shows the horizontal links in black and the vertical links in red.  Items of the same color remain parallel throughout motion which keeps the Control Center parallel to the ground.

The inner linkage is made mostly from gray beams and support the helicopter.  The computer image shows the horizontal links in gray and the vertical links in green.  Items of the same color remain parallel throughout motion which keeps the helicopter mount perpendicular to the ground.

Both linkages are attached to ground at the structural tower shown in blue and are each pinned there on two axes.  The yellow link is the key to the whole thing.  It couples the motion of the inner and outer linkages, connecting to them at the pins shown in yellow.

The final image shows the raised and lower positions superimposed for comparison.  Note the fact that the helicopter linkage moves a greater vertical distance than the Control Center linkage.  This is due to the fact that the yellow coupling attaches to the inner linkage one stud further from the rotation axis than it does to the outer linkage.

Elevation change is the only non-motorized function of the model.
side    side

elevation

elevation    elevation
Image by Benjamin Wendl
Click for an animation of the elevation in motion.
Pitch
The pitch of the helicopter is motorized and controllable via the side to side motion of the control pad. The motor which drives this motion is housed in the vertical portion of the stand which raises and lowers with the entire model.

The helicopter is mounted to the stand with a box structure called a gimbal.  It can rotate on two axes independently or together: pitch and roll.  A worm gearbox in the stand allows the pitch rotation nose up and down about 40 degrees.

As can be seen in the computer image, the high speed motor drives through 2 different silicone belts (red and blue).  The use of belts rather than gears allows the pulleys to slip rather than stall the motor when the helicopter hits the stops.  Each stage of drive belt results in a reduction of about 3:1.  A set of bevel gears then drives torque into a third belt (white) which drives a new worm gearbox (hidden).  The gearbox both drives and supports a 24 tooth spur gear.  The axle at the center of this spur gear (shown in yellow) is coupled to the gimbal (shown in green) with a pair of liftarms such that rotation of the axle directly produces rotation of the gimbal.  Because a worm gear is used, the model maintains the attitude at which it was last positioned.

The movement is quite slow thanks to the total gear reduction of (3:1 x 3:1 x 12:12 x 3:1 x 24:1) = 216:1.

The final image shows the nose up and down positions superimposed for comparison.

Note in the photographs that a number of wires have to be carefully routed through this area without interfering with the motion of the parts.
pitch    pitch

pitch    pitch
Image by Benjamin Wendl
Click for an animation of the helicopter pitching.
Roll
The roll of the helicopter is motorized and controllable via the up and down motion of the control pad. The motor which drives this motion is housed in cockpit of the helicopter model.

The helicopter is mounted to the stand with a box structure called a gimbal.  It can rotate on two axes independently or together: pitch and roll.  A worm gearbox in the body allows roll port and starboard about 20 degrees.  I wouldn't want to roll much further than this in a helicopter.

As can be seen in the computer image, the high speed motor drives through 2 different silicone belts (red and blue).  The use of belts rather than gears allows the pulleys to slip rather than stall the motor when the helicopter hits the stops.  Each stage of drive belt results in a reduction of about 3:1.  A set of bevel gears then drives torque into a set of 8 and 24 tooth spur gears on the right side of the body.  Finally, a worm gearbox (hidden) drives and supports the green axle of the gimbal with a pair of rotors such that rotation of the axle directly produces rotation of the gimbal.  Because a worm gear is used, the model maintains the attitude at which it was last positioned.

The movement is quite slow thanks to the total gear reduction of (3:1 x 3:1 x 12:12 x 24:8 x 24:1) = 216:1.

The final image shows the roll positions superimposed for comparison.
roll   

roll    roll
Image by Benjamin Wendl
Click for an animation of the helicopter rolling.
Rotors
Like virtually all Technic helicopters, the main and tail rotors rotate.  In this case, they are motorized to turn at the same rate via a motor located in the body at the approximate position a turbine would be located in a real helicopter.  The large A and B buttons on the Control Center command the rotor motion clockwise or counter-clockwise.

As can be seen in the computer image (best seen by zooming in) the high speed motor drives through 2 different silicone belts (both red).  The use of belts rather than gears allows the pulleys to slip rather than stall the motor when the rotor is started or stopped.  Each stage of drive belt results in a reduction of about 3:1.  A set of bevel gears drives both the main and tail rotors.

The 24 tooth gear at the front of the assembly does not actually do anything, it is merely meant to represent the spinning compressor fan of a turbine.

It is not immediately obvious from simply playing with the Control Center, but the manual tells you how to lock the rotors on so the buttons don't have to be held.  If the A and B buttons are pressed together and then only one is released, the function will stay on until another red button is pressed.
rotors    rotors
rotors

Click for an animation of the rotors in motion.
2nd Model:  Dinosaur
This dinosaur (presumably a Tyrannosaur) is one of my favorite models ever.  Firstly, it is a Technic model which is not a piece of machinery which makes it a rare breed indeed.  It is the only biologic form ever produced in Technic, and the motion produced by the three motors is nothing short of magnificent.  Each control in and of itself is lovely to watch, but the beauty of the Control Center is that all three can be operated concurrently.

This dinosaur is supported by and integral with a gray stand which contains the Control Center.

This model uses the Flex System more significantly than any other model, and probably to the best effect.  The organic movements would be much more difficult to replicate with gear systems.
2   2
Click to download the LDraw file of this model.
Model by Benjamin Wendl
Click for an animation of the dinosaur in motion.
Bending
The dinosaur can bend down and lower its head almost to the Control Center using a motor mounted in the support stand.  As can be seen in the computer image, the high speed motor drives through 2 different silicone belts (red and white).  The use of belts rather than gears allows the pulleys to slip rather than stall the motor when the dinosaur bends fully.  Each stage of drive belt results in a reduction of about 3:1.  A set of 24 and 8 tooth spur gears then drives a worm gearbox. The output axle (shown in green) turns a pair of liftarms which use push rods to rotate the dinosaur at its pivot axle on the stand.  Because a worm gear is used, the model maintains the attitude at which it was last positioned.

The movement is quite slow thanks to the total gear reduction of (3:1 x 3:1 x 24:8 x 24:1) = 216:1.

The lower set of pictures shows the complex geometry of the legs which mimics the (estimated) musculature of a real creature.  A comparison of the images at the two extreme positions shows the change in muscle and tendon geometry.  This can be further appreciated in the animation.
tilt   tip

leg    leg

Click for an animation of the dinosaur tipping.
Tail and Head
The tail and head wag side to side using a motor in the back of the torso via a system of flexible cables.  The head and tail are linked together so that they move in unison.  This is a reasonable assumption since a creature with such a massive head would need to use the tail for counter balance.

As can be seen in the computer image, the high speed motor drives through 2 different silicone belts (red).  The use of belts rather than gears allows the pulleys to slip rather than stall the motor if the resistance becomes too high.  Each stage of drive belt results in a reduction of about 3:1.  The second pulley drives a worm gearbox. The output pulleys (shown in yellow) are used as cranks.  The left and right side are 180 degrees out of phase and each holds a pair of flex cable ends.  Both the head and the tail form a pull-pull loop.  Movement of the forward cables tips the head side to side, and movement of the rear cables swings the tail side to side.  Because a worm gear is used, the model maintains the attitude at which it was last positioned.

The total gear reduction is (3:1 x 3:1 x 24:1) = 72:1.

The tail is hinged in three places horizontally, allowing it to forma gentle curve.  It does not bend vertically, and the extra flex cable on the top helps to support  the weight.
wag    tail

wag    front

Arms and Jaw
The arms swing up and down and the jaw opens and closes using a motor in the front of the torso.  The arms and jaw are linked together so that they move in unison.

As can be seen in the computer image, the high speed motor drives through 2 different silicone belts (red and blue).  The use of belts rather than gears allows the pulleys to slip rather than stall the motor if the resistance becomes too high.  Each stage of drive belt results in a reduction of about 3:1.  The second pulley drives a worm gearbox (hidden). The output pulleys (shown in green) are used as cranks.  The left and right side are 180 degrees out of phase.  The cranks oscillate the blue arms up and down.  Because a worm gear is used, the model maintains the attitude at which it was last positioned.

The total gear reduction is (3:1 x 3:1 x 24:1) = 72:1.

In addition to the green pulley cranks, on the same axle are a pair of cams shown in green and also used as cranks.  A flex axle connects here (shown in yellow) and attaches to the movable upper jaw.  Oddly, the lower jaw does not really move but rather is fixed at a 90 degree and to the neck which does move.  The upper jaw pivots on the purple axle when the entire head is lifted by the yellow cable around the pink axle.  The red flex cable supports the weight of the head and remains fixed in position while the yellow cable performs the movements.
arms    head

roar    front

Click for an animation of the arms and jaw in motion.
3rd Model:  Boat
The third model, and airboat, is not nearly as inspired as the other two but is still an excellent model.  It uses two of the three available motors and about half of the parts.   It is tethered to the Control Center via wires which are not really long enough to allow you to stand up and follow the model along while it drives along the floor.
3    3
Click to download the LDraw file of this model.
Model by Benjamin Wendl
Fan and Drive System
The model is supported on three hidden tires behind the skirt, two in the front and one in the rear.  One of the front wheels is used for actual propulsion while a large fan in the rear is used to simulate the propulsion method of a real air boat.

As can be seen in the computer image, the high speed motor drives through 3 different silicone belts (red).  The use of belts rather than gears allows the pulleys to slip rather than stall the motor if the resistance becomes too high.  Each stage of drive belt results in a reduction of about 3:1.  The first stage is actually two belts in parallel which drive an 8 tooth pinion gear.  At this point the gear system splits into two parallel paths.

The lower path drives into a 24 tooth spur and then a pair of 12 tooth bevel gears.  The final axle drives the wheel.  The total gear reduction is only (3:1 x 24:8 x 12:12) = 9:1.  The use of a drive wheel on only one side effectively acts as a differential allowing the front wheels to turn at different speeds.

The upper path also drives a 24 tooth spur which is then followed by another set of pulleys with a red belt.  A final reverse gear ratio using spur gears actually speeds the propeller back up.  The total gear reduction is (3:1 x 24:8 x 3:1 x 8:24) = 9:1.

fan    drive

drive

Click for an animation of the fan in motion.
Click for an animation of the drive system in motion.
Steering
The hidden rear wheel can be steering using a second motor in the body.

As can be seen in the computer image, the high speed motor drives through a silicone belt (blue).  The use of belts rather than gears allows the pulleys to slip rather than stall the motor if the resistance becomes too high.  Each stage of drive belt results in a reduction of about 3:1.  A pinion gear on the motor drives a 24 tooth crown which then drives the belt system. A worm gearbox (hidden) is then used to drive a 24 tooth gear into the steering axle.  The total gear reduction is (24:8 x 3:1 x 24:1) = 216:1.

Because of the significant steering angle and the fact that the steering is located in the rear, the model can turn on a very tight radius.
steering    steering

steering

Click for an animation of the steering in motion.
 
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