Phantom Chopper and Simulation Platform

[CP5670]

(click for more pictures)

A search helicopter on a control platform with four degrees of freedom, inspired by the official Lego sets 8485 and 9396. Each position control on the remote activates only one motor. The pitch motor moves the rear actuator only, the roll motor moves the two side actuators in opposite directions and the elevation motor (the XL) moves all three actuators in the same direction. An adder-subtractor system based on three differential gears ensures that the motors' geartrains do not interfere with each other, and that the actuators all move at the same speed. The fourth motor turns an 8t gear inside the turntable's inner ring to allow the chopper to yaw.

The main rotor is built on a swashplate giving it full cyclic and collective pitch control. The rotor blades' pitch levers are connected by flex cables to the platform's base, so the blades automatically adjust to the chopper's position relative to the platform and do what they would do in real life for the chopper to take on that position. At the same time, they are also connected to the flight sticks in the cockpit, which follow the changes in the rotor blades as the helicopter moves on the platform. The helicopter can also be removed from the platform, with the flight sticks used to control the blade pitch directly.

A fifth motor inside the helicopter is used to power the rotors and to raise or lower the landing wheels, with a transmission ring switching between the two functions. The rotor geartrain uses a unidirectional ratchet similar to 9396, which ensures that the rotor blade angles always correspond to the right positions. The tail rotor spins at a 25:9 ratio with the main rotor.

Some other facts:

• The collective movement of the swashplate is based on the fact that the white 5.5L axles have weaker clutch power than most other axles, so the grooved ball can slide over it with little friction.
  
• The remote has a 4-way stick for the pitch and roll controls, built on top of a steering arm with a ball joint receptacle.
  
• The model uses mostly classic Technic parts but several modern 16t gears. Using only the old ABS 16t gears wears down the teeth and a fine powder appears on them after a while, while alternating between the modern and old ones (or using modern ones only) in a geartrain prevents this.
  
• Yes, the minifig is supposed to be controlling it.
  

And here is a video:

Edited September 29, 2013 by CP5670

[Junpei]

It's beautiful! One of the best MOC's I've ever seen, the complexity is just astounding!

[piterx]

that rocks man!

i'll be here waiting for a video :D

i really like the blue too :)

[JunkstyleGio]

Exellent! Can't wait for the video!

[Rishab N]

Nice! I really want to see the video

[jorgeopesi]

Yes I want the video too, good work .

[Doc_Brown]

Absolutely brilliant! Please make a video!

your IR controls are just genius!!!! :thumbup:

Excellent job!

[legomuppet9]

Amazing MOC. It's so complex and still looks great too

[Jim]

Awesome creation!

This MOC screams Video and Building Instructions

[Milan]

8485 reborn!

[Bricksonwheels]

Superb!

[Junpei]

Awesome creation!

This MOC screams Video and Building Instructions

I don't think so. Seriously, do you need building instructions for everything? Looking forward to the video though, it's a brilliant MOC.

[Jim]

I don't think so. Seriously, do you need building instructions for everything? Looking forward to the video though, it's a brilliant MOC.

I would like to see how the base has been created. On the other hand; there are some detailed pictures on Flickr, so maybe you're right

[Lakop]

It will be nice to see it in motion.

H

[Junpei]

I would like to see how the base has been created. On the other hand; there are some detailed pictures on Flickr, so maybe you're right

OK, I understand that. I don't think I could build that adder/subtractor system just from the pics on Brickshelf, it's very complex.

[Jim]

OK, I understand that. I don't think I could build that adder/subtractor system just from the pics on Brickshelf, it's very complex.

I have been looking at some of these platforms, to display the 9396 Helicopter or the 9394 Jet Plane, so it was the first thing that popped in mind

Was even thinking about an NXT or EV3 universal display platform, something like this but a bit bigger for cars, planes, etc.

[Junpei]

That would be pretty awesome, if someone could build the base, they could build anything on top of it!

[CP5670]

Thanks for the comments everyone! I just put up the video in the first post. (slightly choppy since Youtube converts it down to 30fps, but it's not too bad)

Absolutely brilliant! Please make a video!

your IR controls are just genius!!!! :thumbup:

Excellent job!

Thanks. It's surprisingly hard to find Lego pieces with the female ball joint connector, which is the key to making that work. That steering arm was the smallest piece I could think of.

8485 reborn!

That was one of my main inspirations here. I love that set but always thought it was lacking at least one degree of freedom.

Awesome creation!

This MOC screams Video and Building Instructions

I probably won't have time to make full instructions, but I'm certainly happy to provide more pictures if anyone wants to recreate the model or any of its subsections.

That would be pretty awesome, if someone could build the base, they could build anything on top of it!

Yes, the platform can support a variety of other things. The flex cables can be easily removed to make room for them. I tried out some space models like the Galactic Enforcer on it.