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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Ditto on the hanging weight deflection
meters….I have them in my field box for emergencies at the field. A
good laser pointer (Budd) setup will easily show 0.1 degree at the control surface,
and I suspect the digital deflection meters will as well. I think having
better than 0.1 degree of resolution matters (and this is easier to do with
2048 as shown in examples previously given), assuming the rest of the control
system (servos, linkages, hinges) are that good – and if they aren’t,
then my opinion is fix the servos, linkages, etc.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>My recollection is that the best possible
human reaction time in a simple situation is something like 100 ms, with the
average reaction time being about 200 ms. This is actual reaction time,
not anticipation (you can’t anticipate a wind gust that rocks the wings,
but you can anticipate the end of a rolling maneuver or snap maneuver). Reaction
time in a complex situation is a different animal because time is required to
see, process, and then react to the situation – ie, a driver may not
actually hit the brakes for a panic stop until 1 – 1.5 seconds after the
need arises (the additional time beyond 200 ms is the processing/analyzing).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Without starting a brand war……there
was (is) a very popular radio that is a little slow in terms of latency (and
that could have been adjusted to), but the latency deviation (minimum compared
to average, maximum compared to average) was pretty severe…..and that
made the radio unflyable (for me). I much preferred a slower radio (or a
faster radio) with a narrower range of max/min latency. Predictability
and consistency in the control system is very important – even if it is
slow, if it is consistent, it can be adapted too. With all the changes in
radios the past 20 years in terms of resolution and processing speed (FM to
PCM, 512 to 1024, 1024 to 2048, early 2.4 systems, 2.4 add-ons, newest 2.4
systems), I’ve noticed faster response and better resolution.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I think the best radios today are all
under the previously quoted (Tony) 40-50ms. It would be interesting to
note if that study included an analysis of max/min latency. For me
personally, when the latency min/max range exceeds about 20ms, that is the point
at which I can notice the inconsistency (ie, 20-40ms ok, 30-50ms ok, 20-50ms
annoying).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Regards,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Dave Lockhart<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Team JR <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Anthony Frackowiak<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, August 25, 2009
10:13 AM<br>
<b><span style='font-weight:bold'>To:</span></b> jpavlick@idseng.com; <st1:PersonName
w:st="on">General pattern discussion</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [NSRCA-discussion]
SD-10</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Some good points, but I must correct a misconception. There is system
"latency" and then there is servo speed. These are two different
things. Reduced latency does not make the servo faster. It only very slightly
reduces the time between stick movement and when the servo begins to move. It
doesn't make full travel servo speed any faster. This is a subtle point but an
important one in this discussion.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Also, when I want my control throws measured properly I never use the
hanging weight devices. They are not accurate enough. I use a 7"
protractor and pointers on the surfaces. This is much better and lets me detect
even a single digit of travel adjust.<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I still feel that improved resolution is better for pattern flying then
a slight decrease in system latency. But that is just my opinion!<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Tony<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>On Aug 25, 2009, at 6:40 AM, John Pavlick wrote:<o:p></o:p></span></font></p>
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<br>
<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Good point Jay. Remember, no matter WHAT people say
(or would like to have us believe), we live in an analog world. Trying to
digitize an "analog" motion is best accomplished with the largest
number of bits that bandwidth (and memory) allows. But there's more to our
control systems than meets the eye.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'> <o:p></o:p></span></font></p>
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<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>One thing to keep in mind is that Pattern setups are
almost totally opposite from "3D" setups. Pattern strives for
maximum control precision with the least amount of surface travel
whereas "3D" does the opposite. What this means is that our
linkages are configured to give the servo maximum mechanical advantage. This
is like putting a transmission in low gear. You have lots of torque but not a
lot of speed. It also means that the "resolution" of the control system
(meaning servos and encoding process) does not play as large a part in the
total positioning accuracy as it does with a "3D" setup. Not that
high-resolution numbers are "bad" - they're certainly not, but in a
Pattern setup they're not as important as you might think. If the servo has a
3:1 mechanical advantage over the control surface (as opposed to a
"3D" setup which may be close to 1:1) then a 1 degree
"error" at the servo only gives us .3 degrees at the control
surface. Can you even measure that with one of the "standard"
weighted-pendulum deflection gages? On the other hand a "slow"
servo will become very noticeable in this case. When the servo must
rotate to it's extremes while only moving the control surface a slight amount,
it will take a noticeably long time if the servo is slow. When you look at
the mechanics in detail it becomes apparent that a good Pattern control
system could actually compromise on "resolution" and
instead look to improve the "speed" + "response".
So maybe the Airtronics Engineers hit the nail on the head. I'm sure if you
told them to build the BEST control system possible they would throw in 2048
resolution if they could, but in this case they had to make a decision and it
looks to me like they made the right one. As long as you're a Pattern pilot
anyway. :)<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'> <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>John Pavlick<o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><br>
<br>
--- On <b><span style='font-weight:bold'>Mon, 8/24/09, Jay Marshall <i><span
style='font-style:italic'><<a href="mailto:lightfoot@sc.rr.com">lightfoot@sc.rr.com</a>></span></i></span></b>
wrote:<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><br>
From: Jay Marshall <<a href="mailto:lightfoot@sc.rr.com">lightfoot@sc.rr.com</a>><br>
Subject: Re: [NSRCA-discussion] SD-10<br>
To: "'<st1:PersonName w:st="on">General pattern discussion</st1:PersonName>'"
<<a href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</a>><br>
Date: Monday, August 24, 2009, 7:58 PM<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>A liner, non-digital system such as PPM, has
infinite resolution and<br>
therefore the ultimate "smoothness". I agree, however, that you
probably<br>
can't "feel" a 1/2048 digital step. I suspect that the major
improvements<br>
have been in less latency.<br>
<br>
Jay Marshall<br>
<br>
-----Original Message-----<br>
From: <a
href="http://us.mc805.mail.yahoo.com/mc/compose?to=nsrca-discussion-bounces@lists.nsrca.org"
ymailto="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a><br>
[mailto:<a
href="http://us.mc805.mail.yahoo.com/mc/compose?to=nsrca-discussion-bounces@lists.nsrca.org"
ymailto="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a>]
On Behalf Of Atwood, Mark<br>
Sent: Monday, August 24, 2009 4:19 PM<br>
To: '<a
href="http://us.mc805.mail.yahoo.com/mc/compose?to=nsrca-discussion@lists.nsrca.org"
ymailto="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</a>'<br>
Subject: Re: [NSRCA-discussion] SD-10<br>
<br>
I'll take a stab, and I'm blind copying Mike Greensheilds (don't feel<br>
comfortable putting his email out on the list) who is the product manager<br>
for ATX here in the states. He may chime in with additional background.
<br>
<br>
My understanding is that when Sanwa was evaluating speed vs resolution,<br>
speed was deemed a much more critical factor. 1024 resolution is
already to<br>
the limits of our ability to "feel" any difference where as the<br>
speed/latency was much more noticable. Cost does come into
the equation<br>
such that for a $500 radio, they couldn't do both. <br>
<br>
1024 resolution provides better than 1/10deg at 90 deg of rotation.
That's<br>
less than 1/1000" on a 1" servo wheel. <br>
<br>
The speed on the other hand is just now approaching our limits of "feel".<br>
The faster systems clearly feel more connected and are noticable when flying<br>
Snaps and other rapid input maneuvers and especially flying 3D with the<br>
helis. <br>
<br>
So the choice was to invest in a fast response system with 1024 resolution.<br>
<br>
<br>
Does anyone know the tolerances of our servo accuracy? I'd be curious
to<br>
know how high a resolution they can accurately replicate. <br>
<br>
Mike? Any input from the source?<br>
<br>
-Mark<br>
--------------------------<br>
Sent from my BlackBerry Wireless Handheld<br>
<br>
<br>
----- Original Message -----<br>
From: <a
href="http://us.mc805.mail.yahoo.com/mc/compose?to=nsrca-discussion-bounces@lists.nsrca.org"
ymailto="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a><br>
<<a
href="http://us.mc805.mail.yahoo.com/mc/compose?to=nsrca-discussion-bounces@lists.nsrca.org"
ymailto="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a>><br>
To: '<st1:PersonName w:st="on">General pattern discussion</st1:PersonName>' <<a
href="http://us.mc805.mail.yahoo.com/mc/compose?to=nsrca-discussion@lists.nsrca.org"
ymailto="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</a>><br>
Sent: Mon Aug 24 15:30:03 2009<br>
Subject: [NSRCA-discussion] SD-10<br>
<br>
Hi Anthony, Jim, Mark , and Others who Responded,<br>
<br>
<br>
<br>
Thanks for your valuable input. I've read that this radio's resolution is or<br>
is among the very fastest; so much so that even digital servos can't
keep<br>
up with it. I understand that the system is 1024 , but can't help but<br>
wonder why it isn't 2048. I'm sure I'll get past my hangup, but would<br>
appreciate everyone's insight's on that one.<br>
<br>
<br>
<br>
Thanks,<br>
<br>
Frank Imbriaco<br>
<br>
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