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“Phoenix new High RPM” mode to set RPM’s directly. I have found on my motor these settings are within 20-30
RPM tached.
Then there is the ESC MODE: “Phoenix Set RPM” this is a very popular option used by many of the East Coast
fliers, although I have very limited experience with this mode. In the “Throttle” section above I have provided a
link to the CC page that explains the procedure. The FM-9 timer, in the ESC MODE: Phoenix Set RPM allows you
to select one of three RPM that you can program into the ESC.
One other function is the ESC MODE: “Throttle Mode” you can program the RPM as a function of the percentage
of power. This % of power closely correlates to the pulse-width information shown in Figure 3 under “Vehicle
Setup Information”. Looking at the second example the “Desired Head SP” = 9562 RPM the ESC calculates that
you need a throttle setting of 1.430ms (milliseconds) the .430 portion of the number very closely equals to a
power setting 43%. In practical application on my Controller/ESC I noticed that the power percentage is about a
1% high in the throttle setting; so I would start a percent low and measure my RPM. Example – My desired RPM
is 9562 the ESC needs a pulse-width input of 1.430ms. So, using my Will Hubin Timer Controller I select ESC
MODE: “Throttle Mode” set my controller to 42% power and check my RPM. The RPM should be within 75 RPM
of desired, if not bump it up or down 0.5% and recheck. Once you get a feel for your combination this is a
matter of routine and you will quickly get to the required RPM.
One other new development for the FM-9 series of timers is the “Retract version”. I recently received one for
testing and it works very well. I plan to use this version even if I don’t use Retracts. If you do use Retracts – this
timer gives you the ability to pull up the gear from 4-59 seconds after spool-up. I would think for dramatic effect
you would want to pull the gear up after takeoff and two level laps. The Retracts then come down at the 5 sec
warning that you get near the end of flight. One nice thing about this timer it allows you to set additional time,
from 0 – 59 seconds, to maintain power after the 5 seconds warning; thus giving the Retracts ample time to fully
extend. Of course this last function can also be used without the retracts so if a 5 seconds warning is too short
for your taste then you can dial in a few additional seconds.
NOTE: Always hold down the “Start” button when turning on the Controller for programming the timer. Will
states this in his instructions in bold.
Let’s talk about Lipo Batteries with 7 Basic questions:
Define the common Lipo terms. 2S, 3S, 4S etc. 20C, 30C etc.
2S, 3S refers to how many cells are wired in series. “S” refers to series - so 2S means 2 cells are
wired in series 3S means 3 cells in series. The result is the voltage is an “S” multiple of cell
voltage (nominal 3.7 vDC Lipo batteries cell voltage times “S” or 7.4 volts for 2S and 3S equals
11.1 volts). 20C, 30C is a rating that the manufactures place on their batteries to reflect the
discharge capability of their batteries. So, on a 20C rated battery you could discharge an 1800
mah capacity battery at 36 amperes. On a 30C 1800 mah rated battery, the maximum discharge
rate could be 54 amperes. Note: On some low end batteries this rating is unreliable and caution
should be used in discharging at the full rates.
Fully charged what is the voltage of a Lipo cell Standard Lipo batteries are charged to 4.2 vDC
per cell. So if you run a 5S pack, meaning 5 cells in series, the fully charged pack is 21 vDC,
although the nominal rating is 18.5 vDC. 5 X 3.7 equaling 18.5 vDC and a fully charged pack is 5
X 4.2 equaling 21 vDC.
Can Lipo cells be run in series and parallel Yes, they are run in series most of the time but the
Pattern Fliers run parallel pack often to gain capacity. Note that the packs are run in parallel but
disconnected and charged individually. If you have two 4S packs with 1800 mah capacity and you
want to maintain the 14.8 vDC nominal voltage, but increase duration, you could construct a