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New Sets for 1986
New Parts for 1986

1986 - Arctic Action

arctic action

There were eight Technic sets released in 1986, the most ever up to that point.  Two of these are universal sets, two are standard Technic sets, and four are something completely different.  These last four are the Arctic Action sets, which are so unique that they are covered separately on their own category page.  They represent a play theme and are all part of the same connected system.  One of the two new universal sets is motorized, and both feature a wide selection of fairly unorthodox models, which is a good thing.  The go cart features steering and a one cylinder engine.  The new tractor features a pendular front axle and a worm driven implement lift.

Interestingly enough, though this was the first year after the pneumatic system was introduced, there were no new pneumatic sets other than the Arctic Action base.  There were, however, some very important new parts including the worm gear and 2 and 3 blade rotor parts.  Most unexpectedly of all, new Technic figures were introduced which are much larger and more articulated than the standard LEGO® minifigs.  These figures would be used in many sets for many years, especially those which featured the "Tech Play" label.  There are 6 figures in the new Arctic Action sets alone.  Arctic Action is also the first place that white beams could be collected in large number.


8035 Universal Building Set

8055 Motorized Universal Building Set

8842 Go Cart
8849 Tractor
8620 Snow Scooter
8640 Polar Copter
8660 Arctic Rescue Unit
8680 Mountain Rescue Base


Worm Gear
The new worm gear made it possible to achieve very high gear reductions in a very small space.  The worm gear is single threaded, which means that it moves one tooth for each revolution.  Since each of the spur gears can mate with this screw, gear reduction of either 8, 16, 24, or 40 times can be achieved in a single stage.

The other advantage of the worm gear is that it cannot be backdriven.  To understand why, we need to use a little Statics.  When a spur gear tooth pushes on the worm gear, it produces a force in the axial direction, along the direction of the axle.  But the worm teeth are not perpendicular to this force because of the pitch angle of the screw, so the screw works like an inclined plane.  The force can be broken into two components.  The tangential component tends to try to rotate the screw.  The normal component tends to try to slide the screw along the axle, but it also produces a frictional resistance in the same direction as the tangential force.  If the friction is bigger than the tangential force, the screw cannot turn.  Since the tangent force and the friction both increase proportionally to the applied gear force, the gear can never turn no matter how hard you backdrive it.  If the pitch angle is big enough, or the friction coefficient low enough, some worm gears can be backdriven.  An example is a recirculating ballscrew such as are sometimes used for automobile steering or commercial aircraft horizontal stabilizer trim.

This worm gear has only ever been made in one size and, until recently, was only available in black.

A pair of parts were introduced which are commonly used as rotors, with 2 and 3 blades respectively.  They both have a cruciform slot in the center to allow them to rotate with an axle.  They then have a stud which can be used to attach plates or other parts, and finally a hole on the tip.  These parts would end up getting used in lots of applications other than just helicopter or airplane blades.

Technic Figures and Accessories
Technic figures were introduced this year.  These are not only much bigger than the standard LEGO® minifig, they are vastly more posable:
  • Neck:  3 degrees of freedom (ball)
  • Shoulders:  2 degrees of freedom (front-back, up-down)
  • Elbows:  2 degrees of freedom (front-back, in-out)
  • Wrists:  1 degree of freedom (rotation)
  • Hips:  2 degrees of freedom (front-back, side-side)
  • Knees:  1 degree of freedom (front-back)
  • Ankles:  3 degrees of freedom (ball)
A number of accessories were also introduced for the figure.  A special seat (pictured) was specially made to fit the figures, although many sets later used it even without the figures.  There are helmets with transparent visors.  The Arctic Action sets also have skis and ski poles.



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