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Mar 08, 2018, 10:08 AM
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RX120-2S - Printed size 120 helicopter with power from 2S battery - final version.

I want to thank Mike Jennings (MikeHRC) for the translation!!!

Russian version

After a long break, we finally managed to assemble the final version of the RX120-2S, a printed 120-size helicopter powered by a 2S battery.

The assembly of this version of the helicopter stretched into 3 stages, therefore, those who do not know it, I recommend that you get acquainted with the previous two parts of this story.

I'll start with a general view, the helicopter outwardly almost did not change, only slightly elongated the caudal fin .

However, under the canopy the changes are more noticeable. The most important changes have touched the frame.
Frame - I reworked using the flight controller Align 150GRS. To simplify the assembly, the elevator servo has swapped places with the main motor. This was done in order for the servo to work in the right direction, and it would not have to be reversed.

In addition, I changed the front part of the frame into which the flight controller and speed controls were directly mounted. The stack of the flight controller and speed controllers installed in the special recess of the frame will be more protected, and the appearance of the assembled helicopter becomes more concise. Also, the upper part of the frame - the servo holder - was reworked. I slightly changed its design, but its functionality remained the same.

All components from the previous assembly, I installed on a new frame. I started with the tail assembly. Installed the tail engine, drive shaft, propeller and gears.

The tail was assembled easily and not forcedly, as the print quality of the last two batches of frames was on top. It did not take long to calibrate the landing holes for the tail boom and align the drive shaft alignment.

After assembling the tail, also without any special adventure installed all the other components of the helicopter on the frame. The only thing had to be a little tricky with the extension of the wires of the main engine, and the laying of the wires from the tail engine.

In addition, I slightly modified the stack of the flight controller and speed controllers, making it slightly lower in height.
For this, from the regulator board, I dropped a large ceramic capacitor, and transferred it to the power connector. This allowed to lower the flight controller board closer to the controller board and reduce the height of the entire stack. This procedure is not required at all, but since after the previous assembly, I had to solder together the flight controller and speed controllers in one stack, I decided to do this operation to reduce the stack height.

All the rest of the mechanics remained unchanged and was installed in its place.

The weight of the helicopter without the battery was 53.2g, the flight weight with the battery at 330mAh came out 71.9g.

For clarity, I took a photo of all the details of which the helicopter consists in disassembled form. I did not disassemble my head, but I think that it turned out to be interesting.

Well, as usual, in the end, a group photo of all my models, RX100, RX80, RX120-2s, RX120.

Last edited by remlen; Dec 10, 2018 at 02:23 AM.
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