<div>Dean,</div> <div> </div> <div>Thanks for that information. I'll have to chew on that for a while.</div> <div> </div> <div>FWIW, I have always taken a simplistic approach to right thrust and rudder trim. With the plane properly balanced (laterally) and with the rudder at neutral, I pull the plane to vertical and see which way, if any, the plane deviates. This determines the need for thrust change. After the thrust is adjusted, I fly the plane from horizon-to-horizon with the wings level, and see that the plane tracks a straight line. Trim the rudder accordingly.</div> <div> </div> <div>I repeat the above exercise several times, preferably with no wind, and with the plane in different orientations (left-right, right-left) in case there is wind.</div> <div> </div> <div>My viewpoint is that the right/left thrust is most critical when the prop is heavily loaded, ie: vertical climb. In level flight, the right thrust alignment has little to do with yaw
trim, except for the slipstream effect which seems to always be taken care of by the vertical climb test.</div> <div> </div> <div>The slipstream effect applies whether the plane is upright or inverted. IMHO, slipstream is best taken care of by engine thrust, NOT rudder trim, since it will always change with airspeed.</div> <div> </div> <div>Any other rudder inputs needed are usually (maybe always?) a result of gyroscopic precession, which is a dynamic situation that can't be trimmed out by a static control mix. This is why you might need left rudder input on an inside corner at the top of a square loop. I had a plane that required lots of right rudder on the outside corners, and slight left rudder on inside corners. No trim could take care of that, I just had to learn the right stick inputs (muscle memory).</div> <div> </div> <div>As for the bias on spin entries, inverted vs upright, this could be affected much more by tiny differences in the left/right wing
panels, incidences, etc. Basing a rudder trim setting on this could be risky.</div> <div> </div> <div>The programmable mix that you incorporated, above 2/3 throttle, is interesting. It does require learning proper throttle management, as you suggest. But, again, the airspeed will dictate how much mix you will need. So, don't give throttle above 2/3 until you have pulled the nose vertical and are at the vertical terminal velocity, THEN give full throttle. :-)</div> <div> </div> <div>I'm not in any way disputing your results. I have a tendency sometimes to play the devil's advocate.</div> <div> </div> <div>Bob R.</div> <div> </div> <div><BR><BR><B><I>Dean Pappas <d.pappas@kodeos.com></I></B> wrote:</div> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid"> <META content="MSHTML 6.00.2900.2802" name=GENERATOR> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>Hello
Vicente,</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>The trimming adjustment procedure for right rudder with throttle couple I will describe was developed with the Excelleron that I reviewed for Model Aviation. I synthesized this method, based on the several different methods I heard described. As Jason said, some of them did not fly right. The Excelleron is a very good flier, and with a dependable muffled 120 two-stroke I would use it a low-hassle practice ship. Like most airplanes, it required about 2-3/4" of right thrust and a small amount of right rudder to make the plane trim normally. The predictable unwanted effects in spin entries and loops (especially the outsides) were present but not unusually bad.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>So
what I did was </FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>1) Set the rudder dead straight and not touch the rudder trim lever again.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>Confirm that this is really the middle with repeated upright and inverted stalls/spin entries, to make suer the plane does not have a bias to either side.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>2) reduce the right thrust to a "guess" setting that is enough for whatever throttle setting and speed you fly your normal level lines.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>You test this with shallow climbs at 2/3 throttle, and small loops at that same throttle. I ended up with about 1-3/4 degrees. </FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>3) Set up a throttle into rudder curve mix and keep the percentages at zero from idle up to 2/3 throttle. Then add a slop from there to full throttle,</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>and adjust those upper coupling ratios to get a straight vertical line.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=932202016-21022006></SPAN> </DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>Limitations: </FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>Never fly above 2/3 throttle in level flight.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>Never push the throttle up too soon before pulling or pushing to a vertical.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff
size=2>Avoid sudden throttle changes</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>In other words, this is not appropriate if you have not mastered purposeful throttle management.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2></FONT></SPAN> </DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>Hope this helps,</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006><FONT face=Arial color=#0000ff size=2>Dean P.</FONT></SPAN></DIV> <DIV><SPAN class=932202016-21022006></SPAN> </DIV> <DIV> </DIV> <div><FONT face="Times New Roman">Dean Pappas</FONT> <BR><FONT face="Times New Roman">Sr. Design Engineer</FONT> <BR><FONT face="Times New Roman">Kodeos Communications</FONT> <BR><FONT face="Times New Roman">111 Corporate Blvd.</FONT> <BR><FONT
face="Times New Roman">South Plainfield, N.J. 07080</FONT> <BR><FONT face="Times New Roman">(908) 222-7817 phone</FONT> <BR><FONT face="Times New Roman">(908) 222-2392 fax</FONT> <BR><FONT face="Times New Roman">d.pappas@kodeos.com</FONT> </div> <BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px"> </BLOCKQUOTE></BLOCKQUOTE>