[MOC] Mini 42145 - Airbus H175 Rescue Helicopter

[Ngoc Nguyen]

The next installment in the mini replica colletion: mini Airbus H175 Rescue Helicopter.

 

DEVELOPMENT

Even though it is based on the original 42145, I don't like the original color scheme, because neon yellow is a dreadful color in real life, and white ages horribly. Thanks to the release of the 42154, I can build this color scheme instead.

 

 

The original 42145 has a body of 11M width, and I want the mini model to be motorized as well, so I made the mini fuselage 9M wide. That means it wraps around the battery box completely. and that is the root of the main challenge of the design process. To ensure structural integrity, I have to essentially build a skeleton that wraps around the connection points of the battery box. I even have to use the switch axle hole to connect the vertical support. I also added the diagonal support for the tail to prevent it from bending down, a phenomenon that happens to the tail of the original 42145.

 

 

The placement of the motor is also problematic. It has an effective height of 4 studs, but because of the 0.5 stud bumps on both sides. the axle hole is offset by 0.5 stud. And the only place to put it is right above the battery box. The bright side is that thanks to the 0.5 offset, I was able to get a 8/16 gear ratio right off the motor. There is space for only two motorized functions, so I decided to motorize the rotor blades and the landing gear, while the winch will be manual. Since the blades only spin in 1 direction, and I'm not really a fan of the 2-speed gearbox, I gave made the switch for the blade work only in one direction. On the other hand, I want the switch for the landing gears to be bidirectional, so I put a direction reversal in the middle.

 

The transmission for the rotor blades is as follows. The axle from the switch will go through a 20/12 gear ratio to the tail rotors to make it spin faster, while it goes through a ratio of 12/28 to the small turntable that drives the main blades, so there's a noticeable difference between rotation speed.

 

The landing gear function is achieved through a linear actuator that pushes the linkages of the front wheels. The linkages of the front wheels are connector to those of the rear wheels through a 13L beam running in the middle, above the battery box. Both front and back wheels use past-the-midline lock mechanisms.

 

This is the whole thing in one photo. As you can see, even though this model has a fairly generous body width (unlike the mini Osprey), things squeeze pretty tightly together. Every cubic stud is premium, and no space goes to waste.

 

In terms of appearance, I think the original 42145 just looks odd. It doesnt look like or even looks closely like the real H175. Therefore improving the look is also a goal of the design process, and Im very happy that I can pull it off.

 

 

FUNCTIONS

Most functions and details of the original model are replicated:

- Motorized landing gears
- Motorized rotor blades
- Manual side winch
- Diagonal front doors
- Sliding side doors
- Side rescue light
- Pitot tubes

 

 

Demonstration:

 

 

INSTRUCTION:

https://rebrickable.com/mocs/MOC-192494/nguyengiangoc/mini-42145-airbus-h175-rescue-helicopter

 

[arijitdas]

Another fantastic miniature build of the original set. I have become a great fan of your Mini series builds. Awesome job @Ngoc Nguyen !!!!

[Paul B Technic]

Wow, this has come together really well. Another great build from you.

[grum64]

Another excellent mini build and a great presentation 👍

[Ngoc Nguyen]

On 8/13/2024 at 12:18 PM, arijitdas said:

Another fantastic miniature build of the original set. I have become a great fan of your Mini series builds. Awesome job @Ngoc Nguyen !!!!

Sorry for the late reply, thanks a lot!

 

On 8/13/2024 at 1:54 PM, Paul B Technic said:

Wow, this has come together really well. Another great build from you.

Thanks for the compliment!

 

On 8/13/2024 at 9:48 PM, grum64 said:

Another excellent mini build and a great presentation 👍

Thanks for the support!