<br><font size=2 face="sans-serif">Hi All,</font>
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<br><font size=2 face="sans-serif">I'm going to branch off a little from the OS160 setup thread because it brings up some good points. Here are some of my thoughts on prop selection. With the total power available with the 2-cycles, you do not necessarily need to use the prop that gives the most-ridiculous-ultmate-power. In fact too easily, the horizontal & vertical speeds can just look ridiculous fast. Unlimited power is easily achievable given a variety of setups. </font>
<br><font size=2 face="sans-serif">1. The power "setup" or "delivery" is what we should really be after here as the main goal. </font>
<br><font size=2 face="sans-serif">2. The overall speed envelope is critical to achieve a consistent looking pattern flight to flight, day-to-day. </font>
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<br><font size=2 face="sans-serif">Setup: Throttle servo: start with the throttle servo in the 1/2 stick position with a medium or long servo arm. On the carb, I use the longest position available on the arm. Adjust the pushrod to ensure the throttle barrel is 1/2 or a little less open when the throttle servo is at 1/2 throttle. I use ball-links to ensure positive control of the throttle arm/servo connection. Use the throttle ATV to adjust the high and low points. You may have low ATV numbers, but I don't think this is necessarily bad. The longer servo arm will make for more linear movement of the throttle pushrod. (this will affect the Throttle curve later). </font>
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<br><font size=2 face="sans-serif">Throttle curve: This is speed-maneagements best friend! Lean to use this function. You do not want a power setup where the engine is producing 75% of the power when the throttle stick is at 1/2 position. Once the engine is adjusted to run well in the midrange and top end, use the throttle curve to adjust the engine rpm in the range you normally fly. This is the easiest way to slow the plane down for horizontal lines, if you are uncomfortable flying maneuvers with the throttle stick in the 1/4 stick range. I find that I need a steeper line in the beginning to have prop wash over the rudder for stall turns, then a flatter section for a while, then a steeper section so that the power comes on and off during the last 3-4 throttle stick positions. I find I'm more comfortable flying at around 5/8" to 3/4" throttle stick position, so I use the curve to adjust the power available at that setting. Y
ou can do this with any engine (even the YS need a throttle curve). What we are talking about here is tailoring the speed of the plane to the position you are comfortable flying throttle stick in.<br>
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<br><font size=2 face="sans-serif">Prop: Of course, the prop has a huge impact on overall speed. The prop and throttle curve go hand-in-hand to control the speed of the plane. I do not want a large speed envelope "gap" between low throttle speed, horizontal maneuver speed, and full throttle speed. Nor do I want a prop that exaggerates the velocity of the plane or any on-off-pipe issues. Generally, I think more diameter and less pitch is the way to go (but that's just me). Nor do I want to run a prop that 'overloads' the engine just to make it slow down. I want to run a prop that is easy on the engine, has good breaking, and has good acceleration after the upline snap. Use the throttle curve to adjust where the power comes on/off to suit your flying style. </font>
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<br><font size=2 face="sans-serif">In 25 words or less: 1. use the throttle curve, 2. don't run a prop which allows the plane to really accelerate away from you or has a large velocity gap. IMHO.</font>
<br><font size=2 face="sans-serif">Thanks,</font>
<br><font size=2 face="sans-serif">Jim W.</font>
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