This project started way back in December 2010 when I first got the V120D02 helicopter. It was a great helicopter, and love the instant response of the tail shaf driven rotor. Conventional motor driven tail requires the motor to spin up before the tail response. Since the motor has an inertia, it takes a while for it to spin up before the tail reacts. This is especially noticable when going backward or tail is facing the wind. When the tail go from leeward to windward side, tail goes from being assisted by the wind to suddenly have to fight the wind to keep the helicopter from spinning out. Tail driven helicopter will respond way faster than motor driven tail.
The major weakness of the V120D02 as those darn gears. They strip with just a touch of the tail rotor on the ground. Something had to be done.
This is almost 2 years in the works since completion of first drawing in spring
of 2011. The goal was a modification that is up to high industry standard. This
is certainly not my first project. I designed almost all the mod parts for PN
Racing. Many top drivers in the World Cup use my parts because they perform
better than others on the RCP track.
Still, this clutch is a steep challenge because of the size and lack of space. I wanted full performance envelope without any compromise in reliability or function. The project went thru 2 prototype. Took many months to get the first one. It worked, but it was not refined enough. It was redesigned again, which is finally this one. In the mean time, there has been various modifications on the forum to address this tail gear. I still wanted a top quality clutch that can do the most severe 3D maneuver and not slip even when wet. From testing, it has shown that will not slip even with moisture from landing on grass. For extreme maneuvers, you can adjust the clutch from loose to full lock up. (At high tension, felt like there is enough torque capability to even break the gears. That has to be enough torque for anything! ) Still, the ultimate test is the user. So far there is very positive feedback.
At one point, I was going to shelf the project because of the risk of not breaking even. Then decided to heck with it. I wanted the clutch regardless because this helicopter is way too much fun.
Next project will be the Blade 130X tail gear :)