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<DIV><FONT size=2>#1) If you know you have glitch problems... don't
fly. "glitches" don't fix themselves, they just get worse.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I chased glitches in one model for almost 3 months. (I
didn't fly it... its still in one piece.) The glitches first appeared
(that I noticed) about the time I had a servo fail due to stripped gears I
replaced the servo and the plane didn't pass range checks again. I
eventually replaced EVERY servo in the plane with a different brand AND replaced
the servo extensions. (after trying several servos of the original
brand)</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>It is possible, that you had a servo that was starting to
fail, and that servo (especially if on a long extension) would have created a
feedback interference issue.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>There are many other possibilities... Once the model has
had a major impact, its pretty well anybody's guess if the radio issues found
were existant prior to the crash or caused by the crash.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>FHH</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=geobet@gis.net href="mailto:geobet@gis.net">george w. kennie</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, November 07, 2006 1:29
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [NSRCA-discussion] RF
Interference</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Hey Guys,</FONT></DIV>
<DIV><FONT face=Arial size=2>Looking for some input here regarding RF
interference. </FONT></DIV>
<DIV><FONT face=Arial size=2>I lost Javelin number 3 this morning which I had
been having glitching problems with for over a month. </FONT></DIV>
<DIV><FONT face=Arial size=2>Originally I had been flying the plane with an
OS-70 surpass II , but when the motor lost performance I decided to go for a
little more oomph and installed a Saito 91 which was actually 2 oz. lighter.
The Saito drove me nuts 'til I finally figured out the Low speed needle
and then I became very satisfied with the extra performance. The next
performance improvement I decided on was to replace the wing mounted gear
which was prone to bending even on greasy landings, so I picked up a set of
carbon-fiber gear (one piece) and bolted the unit to the bottom of the fuse
just ahead of the wing which solved all the ground handling problems and also
gave extra prop clearance. Now these two mods were executed about the same
time and subsequently I started to experience glitching problems. When it
first manifested itself it was in the nature of the throttle servo pulsing
intermettently on the ground during warm-up and then it would smooth out and I
would take off and fly and it would seem O.K. Feeling uncomfortable
with this condition I decided that I must have some metal to metal contact
somewhere. Due to the fact that the 91 shaft was longer than the 70 I was
forced to push the engine back all the way in the engine mount and I thought
the carb might be contacting one of the bolt heads holding the mount to the
firewall. Well, I corrected that problem only to find at my next outing that I
still had Intermittent throttle pulsing. Back to the drawing board, I next
decided that the receiver was suspect as it had been through a previous
incident, so I installed a different receiver. Next time out the plane
flew like a charm and I had about 4 outings with no glitches and then on
my 5th outing I got a resumption of the throttle pulsing ( actually, all
servos were jittering, but the throttle audibly let you know it). I actually
flew some flights like this and would experience serious glitches on the same
maneuver in the same position within the maneuver repeatedly. It also seemed
to be vibration related as I found that when I shut off the motor
in flight the glitching would cease. Then I decided that the wiper on the
throttle servo might be bouncing on the surface of the resistive
element and giving me spurious signals within the system, so I decided to
change out the throttle servo. In the process of disconnecting the throttle
servo from the receiver I had inadvertently left the receiver ON and
when I lifted the receiver things started jittering,.......aha, pulling on the
antenna wire was giving me spastics ! O.K., got ya, ya buggar!
Spun out to the LHS and picked up a new antenna and figure VOILA home free (
with a little knawing feeling of wonder about why did the first receiver do
the same thing? Do I have two receivers with broken antennas, after all I
have strain reliefs on these things hmmmmm ???) </FONT></DIV>
<DIV><FONT face=Arial size=2>Well I show up at the field today with the new
throttle servo and new antenna and start the engine which purrs like a kitten
with no pulsing. GOTCHA ! Taxi out to the center of the runway, switch
to low rates and feed it the oysters. Beautiful long low gradual climb out to
5 ft wherupon the right wing goes to KE position (L to R take-off), I slam in
full left aileron and left rudder and it didn't budge as the nose came down
and the right wing made contact with terra firma Pogoing the thing to
oblivion.</FONT></DIV>
<DIV><FONT face=Arial size=2>I had to go get petrol, and as I'm driving I'm
doing the Sherlock thing, thinking, the only thing I changed is the motor and
then It hit me! Holy Smoke, I put carbon fiber gear on that buggar.Could I be
getting some kind of reflections from that thing to the antenna?? After all,
The symptoms are identical to the symptoms that occurred when the antenna
was broken.</FONT></DIV>
<DIV><FONT face=Arial size=2>So you can see what my question is here. Has
anyone experienced any kind of interference caused by using carbon fiber gear?
I remember some of the guys with carbon reinforced fuses talked about how they
had to run the antenna outside of the fuse. Also the Javelin has that chrome
monokote under the transparent blue and I've heard about that causing
potential interference, but I have had two previous Javelins with the antenna
run the same way ( on the outside of the bottom of the fuse) With no
interference problems and many many flights.</FONT></DIV>
<DIV><FONT face=Arial size=2>What ch'all think? Ed Alt? Any of you
electronic gurus?</FONT></DIV>
<DIV><FONT face=Arial size=2>Georgie</FONT> </DIV>
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