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Original Year
 1999
# of pieces
 309
Categories
 Aircraft:  Helicopters
Dimensions
 47(L)x18(W)x17(H)
without rotor
Features
 Rotating main and tail rotor,
working single axis cyclic
Other Views

8444 Air Enforcer
iso revolve
Click the image to download the LDraw file of this model.
Model by TotalyWicked
This rather skeletal helicopter was released in 1999.  It uses the previous rotor head system to simulate cyclic pitch, but adds many newly available aesthetic details using flexible axles, ribbed hoses, and the new curved panels.  The blue color is unusual and some of these parts exist nowhere else.

Functionally this helicopter does not break any new ground.  Although the cockpit is nicely faceted similar to an RAH-66 Comanche, the rest of the styling is not consistent with that.  The AH-64 Apache, on the other hand, has a similar landing gear arrangement, a somewhat similar canopy, and weapons pylons which look somewhat like the panels in this model.  The name "Air Enforcer" also suggests some sort of military chopper, but I suspect that LEGO® chose the blue color and ambiguous styling to make it more like a police helicopter.

Features
Rotors
The rotors' rotation is driven by an input ball gear on the left side.  This crank drives a set of 12 tooth bevel gears giving the main rotor a ratio of 1:1.  The main rotor axle also drives another set of bevel gears which rotate the tail rotor.  There is a 20:12 tooth bevel gear pair at the tail, so the tail rotor rotates 1.67 times faster.
main    rotor
Click for an animation of the rotors in motion.
Cyclic Pitch
This helicopter uses a cyclic pitch system very similar to 8856.  Real helicopter cyclic works by changing the pitch of individual blades as they rotate using a swashplate.  For example, the leading and trailing blades may be at 10 degrees of pitch, while the port and starboard blades are at 5 and 15 degrees respectively.  This model pivots the entire rotor head instead.  If a real helicopter did this it would risk striking the rotor against the frame.

The rotor axle drives a spherical ball gear.  A  part with 4 ball joints which is similar to a swashplate (but originally used as a steering hub) connects to a flex cable to allow the head to pivot on fore and aft.  A torque link keeps the swashplate from rotating.  Inside the swashplate is a four blade rotor part.  The rotor has tabs on the inside which mate with the ball  gear to transmit torque.  Because of the shape of the gear, the rotor can pivot while still rotating.

The control of the cyclic is from a stick at the pilot's  and co-pilot's position.  A flex cable connects the two together as well as connecting to the rotor head.  Fore-aft motion of the stick  pushes and pulls the cable.  The flex cable runs up to a link which lifts the swashplate.
cyclic    cyclic

rotor
Click for an animation of the cyclic in motion.
Landing Gear
The solid rubber wheels are attached to a triangular gear strut which is made to look like it has sprung suspension but is actually solid.  There is a solid axle inside the ribbed hose.
skids
 

Other Views
Side View
side view
 Top View
top view
Front View
front view
Back View
back view
Computer Render
Render

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