stevem
Senior Heliman
Location: Oklahoma
| Can those of you who have this problem with the tail rotor not being able to keep up try this: Get in a stable hover (outside on a calm day) and then apply full throttle quickly and smoothly while inputting right rudder to compensate. If you can hold the nose straight or even rotate the nose right, then it is not a power issue, it is the tail lagging for some reason.
I have ran both the hummingboard and seperates. With the Hummingboard, I ran a 280BB on the stock 10 tooth pinion and as you advanced the throttle to ascend, the tail would slowly loose track and begin to spin. Another person mentioned the mix issue which makes sence to me so I swapped in an 8 tooth and the problem was gone. The mixer will add a certain amount of tail rotor when it sees a certain throttle position. If you are spinning the blades faster (higher speed motor) at that point, then of course the tail will begin to drift. As you advance the throttle more the problem becomes even more pronounced.
I now use seperates with a HH gyro. On an 8 tooth main pinion, and the gyro set properly, the tail would wobble a bit to the right (nose left) if I stabbed the throttle but would quickly recover. You could also hear the tail rotor screaming to keep up. I used a 10 tooth pinion on this setup and I could break the tail loose when I gave a quick stab of throttle - you could hear the tail rotor screaming but it simply was not quick enough to cope. It would quickly recover when I lessened the throttle. If I input right rudder with the throttle input, I could keep the tail steady. This indicates that the tail has enough power to compensate but is a bit slow to respond.
Now I use a Razor brushless. At first, I used an 8 tooth pinion and had similar results to the 10 tooth above. I managed to strip that pinion and switched to the stock 10 tooth. Now I really have to be on top of the tail rotor if I plan to ascend quickly. Managing the rudder, I can keep the tail straight on a full throttle ascent, but have no extra for rotating the nose to the left if I need it. But I can torque spion it at about any time I need.
I am not saying that there are not times when the tail power drops - near an end of a discharge (around 20 minutes) No matter what I do, I could not keep the tail straight in a full throttle blast. But the drop in power is obvious as the heli does not climb like when the battery was fresh.
This is just my experience. Regardless if it is a loss of power to the tail, an improper pinion/mix issue or simply the tail not being able to keep up the end result is pretty much the same as is the fix. A smaller main pinion seems to help in all of the instances I have listed above. To find out the answer, someone will need to measure the voltage on the tail motor under various conditions and verify what the drop actually is enough to cause the tail to drop out.
Good luck guys. Have fun and remember this is a hobby and supposed to be fun!
Steve |
