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<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></BODY></HTML>