I am confused as to where the signal comes from to operate the speed controller. Typically a radio does that and with a control line, there is no radio. Also, what is governor mode.
Thanks,
John
John,
I'd suggest asking electric questions in the electric forum---basically not because we won't answer here, but sometimes we don't see the question.
But John is right. The throttle setting comes from a tiny little chip known as a "timer/throttle", mainly because it provides both functions. It's output is the same electronic signal that a RC-receiver would give to a servo or an Electronic Speed Control (ESC). Here is a link to one I use, the JMP-2, but there are a lot of comparable versions out there that work well too.
http://www.bsdmicrorc.com/index.php?productID=642Regarding the governor--that is built into the ESC unit. Basically a given throttle setting is mapped into a fixed rpm value. So during the flight, if you want 9000rpm, then the governor will hold 9000 rpm under all load and battery conditions. Of course the rpm setting must be compatible with the load and battery voltage over the range one will see during a flight (the battery voltage drops as the flight progresses).
If your ESC doesn't have a governor mode (most don't), then some timers have a throttle increase function. As the flight progresses, the throttle is slowly ramped up from its start value to a finish value. More or less this tries to compensate the falling battery voltage, so the cruise rpm stays about the same during a flight. Of course when the load increases (like when you pull the nose up and the plane begins to slow down), the rpm will drop a little.
Most of us use governor mode for our "big" PA stunters, but often for the 1/2a stuff just go for a non-governor ESC (they are cheaper) and use the throttle compensation in the timer.
Hope that helps.