<br><font size=2 face="sans-serif">Hi Emory,</font>
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<br><font size=2 face="sans-serif">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>
<br><font size=2 face="sans-serif">Jim w.</font>
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