Hughes500Pilot
Key Veteran
Location: Anaheim, CA
My Posts This: Topic Forum | The clutch does not engage while the engine is in low RPM, such as when it is at idle. But as you increas throttle, the RPS'd increase and the clutch grabs and starts to spin the main blades.
Now that we have the clutch engaged and the blades spinning, whe need to lift the heli. To do this, you increase the pitch of the blades. The blades "bite" into the air and lift the helicopter. The more pitch, the more bite, or load on the blades and the engine.
If you were to have very high pitch on the blades and low RPM, you would burn up the motor. Kind of like driving a car SLOWLY up a hill in 4th gear. If you had very little or no pitch on the blades and the engine were at high RPS, the engine would over-rev and blow up. Kind of like driving your car at highway speeds in 1st gear.
So, what you need to do, in theory, is have a fixed blade speed and engine speed. If you want to increase power, you increase the throttle. HOWEVER, at the same time, you increase the blade pitch. Therefore, the RPM does not increase - only the power output of the engine does.
If you lower the blade pitch, you also lower the engine throttle at the same time. The RPS's do not decrease, because you lowered the blade pitch.
If you have the throttle and collective pitch set correctly, you engine RPM stays the same all the time. When you increase the blade pitch, you add power to the engine - but just enough to match the increase in blade pitch. Therefore, you RPS stays the same. And when you lower the blade pitch, you need less power from the engine so the throttle lowers and the power is reduced. But again, you only lower the power of the engine just enough to equal the lowered blade pitch. Again, lower pitch, less engine power needed - And the engine RPM stays the same.
Hope this helps. -Steve |
