xlcrlee
Mar 05, 2009, 10:50 AM
The aeroelastic flexing rotors coupled with the stabilizing system, the complex airflow (with 3-D momentums), and the motors form an interactive self-stabilizing system. I worked on many such (non-computer, but computer-simulated & analyzed) systems both in grad school and doing classified work at General Dynamics .... so when I first spotted this in the TZ-1, I was interested but unsure of my observations. Now I am more sure. This is likely most easy to note with a heli that is physically trimmed to be hover-neutral (not with the Tx trims!), either by the user or a chance lucky purchase. And of course with the fwd training vane removed!
the elements:
1. the rotors flex under load and assume a new twist and front profile, etc, under flt. load, influencing the airflow and the motor function.
2. the motors' speeds (re: heat and current draw) interact w/ each other via total LIPO output, pilot power-input, the IC chip and the rotors.
3. the airflow connects the rotors and the motors.
4. pilot > only for transition phases (entry/exit), plus external macro airflows (room and heli-generated air currents).
observation:
Once the heli is in a stable condition (fwd flt, circling fwd flt, slow rev, slow circling rev, pirhuetting in-place turn or hover) .... the rotors will flex to adapt to that condition, the motors' currents & heat will stabilize (more back EMF = less current draw at higher RPM), and the complex recirculating airflow system (with significant momentum) will stabilize. It is the transitory phase of entering the new condition (requires force-changes) that changes the rotors' twists, like a rotor blade hand-twist, from which position the blades slowly return. Slow sproooooing ... Note: the static, hover and other flt-mode twists are all diff from each other!
So the heli will tend to keep doing what it is doing for some time .... even with the right stick returned to neutral. One can think that it "gets in a groove".
Systemically speaking, it does! This stability (if properly physically trimmed! .... which is not made easier by the interactive nature of the system!) allows abrupt maneuvering (trainer-vane OFF, right?) and is one reason I so love this (these: I now have 4) toy .... Lee :)
the elements:
1. the rotors flex under load and assume a new twist and front profile, etc, under flt. load, influencing the airflow and the motor function.
2. the motors' speeds (re: heat and current draw) interact w/ each other via total LIPO output, pilot power-input, the IC chip and the rotors.
3. the airflow connects the rotors and the motors.
4. pilot > only for transition phases (entry/exit), plus external macro airflows (room and heli-generated air currents).
observation:
Once the heli is in a stable condition (fwd flt, circling fwd flt, slow rev, slow circling rev, pirhuetting in-place turn or hover) .... the rotors will flex to adapt to that condition, the motors' currents & heat will stabilize (more back EMF = less current draw at higher RPM), and the complex recirculating airflow system (with significant momentum) will stabilize. It is the transitory phase of entering the new condition (requires force-changes) that changes the rotors' twists, like a rotor blade hand-twist, from which position the blades slowly return. Slow sproooooing ... Note: the static, hover and other flt-mode twists are all diff from each other!
So the heli will tend to keep doing what it is doing for some time .... even with the right stick returned to neutral. One can think that it "gets in a groove".
Systemically speaking, it does! This stability (if properly physically trimmed! .... which is not made easier by the interactive nature of the system!) allows abrupt maneuvering (trainer-vane OFF, right?) and is one reason I so love this (these: I now have 4) toy .... Lee :)