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Old 10-31-2016, 04:55 PM   #24 (permalink)
Max olivier
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Join Date: Oct 2016
Default k120 frame+servo+main gear modification

Here is my modified k120. Goal is to improve crash resistance, increase agility and reduce weight.
I used some CFRP plates glued to parts of the ABS original frame.
This gives more space for Arrow D03018MG. Thei are fast and metal gear so... no easy stripping and the weight is not much more than original XK servos.
I also glued together with epoxy two main gears so now there should be no more risk of teeths stripping also.
Battery is now on top, so COG is more near to rotor and hopefully heli will be more responsive and with less cross coupling on maneuvres... maybe...
Receiver and ESC are suspended on two ear plugs fitted in a hole in the CFP frame. No more screws to fix the PCB so vibrations should be damped more.
Weight is still similar to the original overall.
After some test flight tests on the next days I will move to next steps:
-lightweighting of the CFRP parts that are now kept "solid"
-think of a way to make the skids lighter and shorter
-Manufacture a new canopy since the original one do not fit any more of course...
-Reduce the tail weight by simplified tail motor mount and maybe reduce the tail boom size... the 5mm CFRP rod seems oversized for this heli...
-Try a CFRP rotor mast in place of the steel one... I bent already 3 of them...

Still open point whre advise is wellcome are:
1-what to do with the feathering shaft... it benbds too easily.
2-Is there any more powerful motor to replace the stock without changing ESC?
3-Any advise on rotor blades replacement? I still have 5 pair of originals but would like to know if more performing blades are available.
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