Mini Chinook, Alternate from parts of 9396 Helicopter
About this creation
I'm proud to present my newest MOC: in anticipation of the twin-rotor helicopter rumoured to come in 2014 here is my rendition of a small Chinook like helicopter.
Plus it's an alternate of the 9396 Helicopter. Although making a small alternate of such a big set hasn't got quite the challenge of limited possibilities. Also it's unlikely that someone will dismantle his 9396 to build this alternate. But since this model uses nearly only standard Technic parts everyone with a good collection of parts should be able to build it. Only exception are the new rotor blades which would need to be replaced by an own rotor assembly, maybe like this:
Of course this helicopter has two counter-rotating rotors:
But there's also a lever on its side indicating more functionality.
Of course it's the winch. But still it's not like you might expect. Let me explain. Just like with the main model of 9396 we are used to switch between functions with these levers. But this doesn't make sense on a helicopter. On 9396 you have to decouple the rotor from the motor to lower the landing gear. Your helicopter would crash before the landing gear is ready.
At least 9396 allows to operate the winch while keeping the rotor running. But only in one direction, since rotor blades don't work in both directions of rotation. And during a flight you can't halt your rotors and reverse the rotation. Correctly 9396 only allows the rotor to be powered in one direction.
So with this model I did something different. With the lever you can switch between lowering and raising the hook or decouple the winch completely. The rotors meanwhile keep rotating in the same direction with only one "motor" needed for both functions (it's a hand of God knob on the back which you will have to turn yourself).
Here is the gearing which allows to select the rotation for the winch:
The gears for reversing the rotation are mounted on a triangle construction and are visible on the other side of the helicopter:
In an official LEGO set the transmission to a winch always involves a part with friction. This prevents the winch from unwinding through the weight of the hooked items. Still I'm not sure whether I like this. So my MOC comes without this feature, but here is how to add it: move the black axle 10 one stud to the back and replace the bush with a "Pin Long with Friction Ridges Lengthwise and Stop Bush". The removed bush goes to the back on the overhanging axle: