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<DIV><FONT face=Arial size=2>At the urging of Dave, I have finally switched to
digital servos on the ailerons. After flying analog servos for 25 years,
it was explained to me that digital servos on the ailerons help looping and
radius of maneuvers. Here is my assessment.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The baseline servos were JR 7005.
The digital servos changed to are JR 9411 servos.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Loops and lines. The first thing I noticed
was that, just as Dave mentioned, loops and loop segments are more
locked-in. The 9411 servos made the wings more stable, requiring less
effort on the maneuvers involving loop segments (most all of the
maneuvers). Analysis- why this occurs- the theory is that during loops,
wing panels generate quite a bit more lift. since the digital servos lock,
and hold center much more agressively than analog servos (holding torque) this
provides very little give in the ailerons during the loop. Regardless, its
a noted difference and clear advantage of these servos.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Rolls and rolling segments. This part of the
analysis was quite a bit more complex. Clearly the digital servos have
more speed and resolution than the analog servos. The holding torque and
contol surface power requires that control throw be reduced to attain the same
roll rate. However, the analog servos would "blow back" at high speed, but
stay deflected at lower speeds. Incredibly, the advantage to this is a
more constant roll rate- independent of speed. The ailerons
(roll rate) would feel more the same at low speed (like the top of an immelman,
loop or vertical line).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Snap rolls. This is what I call the "rubber
band" effect. The analog servos would deflect quite a bit during snap
rolls, requiring one to "unload" the snap (start coming out of the ailerons
before the snap is complete). Otherwise, the snap would be
over-rotated. Actually, this was not too hard to get used to, since its a
very consistent effect. With digital servos, however, there is much less
deflection and thus a more "honest" snap roll. It does snap differently,
but the exit is much cleaner (or easier to have a clean exit).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Exponential. Here is another item of
interest. My initial perception was that I would have to add additional
expo to get the same feel for the digital servos. Since control thow was
reduced (moved in one notch on the servo arm) there was still more roll rate at
full stick deflection (since the ailerons are no longer blowing back like the
analog servos), but not as much roll around neutral. I actually had to cut
my expo in half. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>So, the overall analysis is that the digital
servos provide greater stability of flight, more consistent snap exits
and loop segments that are more locked in. Analog provide more
control roll authority at slower speed and more forgiveness with shaky hands
(the rubber band effect does dampen shaky thumbs). Conclusion- overall
benefits outweigh analog servos- favor the use of digitals. Will stay with
the 9411's.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Don</FONT> </DIV></BODY></HTML>