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Hey Jim,
<br>It would take me 6 months to learn to do all that!
<p>Jim_Woodward@beaerospace.com wrote:
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<br><font face="sans-serif"><font size=-1>Hi Emory,</font></font>
<p><font face="sans-serif"><font size=-1>Going to Apopka? Good question.
Pump pressure and mixture go hand-n-hand. If the engine is rich in
the midrange on the ground, but exhibits symptoms such as: popping
sounds or puffs of smoke when adding power, moments of silence then catch
at full rpm, or does not sustain power on uplines - you need more pump
pressure, then readjust the carb for good ground running. Reducing
pump pressure may yield a good ground running, but it might not yield sustained
power on uplines. I run as much pump pressure as possible, while
maintaining control over the fuel metering in the carburetor. "Shamless
plug" - thats the beauty of the MC carb. You can run a lot of pump
pressure, and just bias the control arm adjustment a little on the on the
carb, then use your transmitter to tune the rest of the throttle-mixture
curve. This way, you always have enough pump pressure. The
real test of the MC carb is in-flight performance. If there are any
dead spots, just note about where the throttle stick was, go into the program,
and richen or lean in just that area. For instance, you can leave
the idle fairly rich, so the engine slows down right away when you reduce
throttle to idle, but if you lean a couple points just above it you get
instant "zippy" throttle response, then make the top point a little rich
to control the top rpm figure. Once you get the right mixture everywhere
you want it, use the transmitters actual "throttle-curve" to set the amount
of power you want for a given stick position. Use this feature get
the right velocity for the throttle stick position you usually fly.
I think I fly mostly around the 5/8-3/4" throttle stick position.
My throtte curve is steep at first to give some prop blast over the rudder
for stall turns, then flattens out quite a bit - barely rising. The
last two & three points of the curve rise very steeply - like a very
smooooooooth switch! Thus, I get 'full' power only at the last two
& three positions of stick movement. The best part is that as
soon as you get back off those top 2 or 3 throttle stick points, the engines
rpm has really dropped - instant speed mangement while keeping the throttle
stick in the position I like to maneuver in! Finaly, mix the throttle
curve to a knob near the throttle stick, you can adjust the rpm while in
flight (although the knob affects the entire curve). There is a learning
curve, but the overall action is superior.</font></font>
<br><font face="sans-serif"><font size=-1>Jim w.</font></font>
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