Firefighting Skycrane helicopter

[steph77]

Hi everybody

here is my entry for the 29th Techlug contest. We had to buil a skycrane type helicopter with manual functions that can be upgraded with powerfunction M motor only.

Searching on the web for actual use of this old heli, i found the fire fighting version and decided to reproduce one of them

here comes the beast:

so can be defined mu goals for that moc:

- Must be playable

- the two functions had to be independent

in two words simplicity and efficienty.

I choosed to place two reversible gearboxes, one for each function

you will see it working in the vid above

About the design, i observed that the main conception line of the real skycrane was probably 'less is more'

So,

I do that also with my lego...

for the details, we have two powerfull engines on the front. when rotors spins, the engines also rotate.

The drive shaft is exposed as the real model, there is no universal joint, just gears and no vibrations .

I opted for a default four-bladed rotor. Not too keen to order two blades that will not serve me anymore. For the tail rotor, it is a compromise. I wanted the finest possible articulation and 40T gear .... is not that which is finer or discreet. So I settled for a mere three-branch connector on which the blades can be attached simply and aesthetically.

On the container. I opted, according to my model of inspiration for a simple and playable stuff. Basically, there are the characteristic line of the skycrane tanks, triangle, manual door that opens by a link. The device is held by friction pines. The container is further equipped with a suction tube that allows a flight reload in a lake or river.

A simple interlocking device allows the stall once ascended to the structure of the bird.

For refulling, kerosene this time, the chopper is equipped with a refueling boom in flight.

Pictures now:

General overview of the bird with its container

Front face with refueling boom

opening element for battery box insertion. The M motor can be installed without any complementary pieces

lateral view without watertank

Stature which imposes I elongate blades to have a coherent rotor diameter compared to the size of the container, from which also the reduction of the transmission shaft

Container detail with its simple locking system (red pins are inserted in the chassis)

opening system of the watertank.

other general view

lateral view

Cockpit detail with the battery box inside

the modules

cockpit without BB: design is not affected

Elements opening for insertion of BB. The glass door is the actual model (lift operator)

more details:

General view of s propellant module, with the two turbines connected to the rotation of the rotor:

Bottom view or seen in lateral winch mechanism and the center one of the two supply gearboxes

The module of one rotor with its anchor points, it is completely independent of the gearbox module

top and bottom view of the gearbox

splitted:

and in LDD renders version:

Finally: the video:

https://www.youtube....h?v=2GZQWy6kicI

hope you'll enjoy that model

Edited October 10, 2015 by steph77

[P3_Super_Bee]

Very well done. I like it.

[Jeroen Ottens]

Great model Steph (as always)

I like the minimalistic design and the playability of the gearbox. The tailrotor looks a bit high?

[steph77]

Jeroen hello, thank you for your nice comment (as always with you as well). For the tail rotor it is actually a little high but it gives the scale model and a burly stature. It is a compromise between design and realism.