[NSRCA-discussion] Ideas on radio beserkness-cause of crash??

[Jay Marshall]

A little advertised problem is interference from cheap walky-talkies such as
those used by hunters. This may or not be a problem in your area - I have
lost two planes directly over a deer stand. We have established that this is
a problem by placing a model in the middle of our field and keying the
walky-talky on and off. There was no doubt that it caused a problem. This is
why I scraped all of my 72 MHz gear and went to 2.4 GHz.

 

Jay Marshall 

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Gray E Fowler
Sent: Tuesday, September 02, 2008 9:30 AM
To: NSRCA-discussion at lists.nsrca.org
Subject: [NSRCA-discussion] Ideas on radio beserkness-cause of crash??

 


Guys 

Yesterday on my 4th flight of the day my PCM Stylus went nuts. PCM program
was set for idle throttle and about 5-6 clicks(trim wise) of up elevator-all
other surfaces neutral, and this was tested as such by turning off the
transmitter.  As I passed by center I noticed that I could not gain altitude
and the the throttle started going from idle to high...then ailerons started
oscillating small left-right deflections. I cut the throttle to the kill
position but the engine persisted up-down bursts. I was able to do a 180
degree turn with aileron coming back to center...never losing altitude, but
unable to change the altitude,elevator seemed unresponsive. As I passed by
center again I was losing more and more control. The plane flew over the
wooded area south of the field at about 200 feet high, I could not turn and
the ailerons rolled the plane upside down and it went straight down into the
trees. This whole episode last about 45 seconds. Cannot find the plane, and
remnants of Gustav are headed my way. 


Plane was new had about 10 flights on it. 

New battery..NiMH 5 cell pack -no regulator (ran 5 cell packs for years, no
regulator) 
Reciever-1999 Stylus PCM-never crashed, wrapped in foam 
New switch 
Transmitter-1999 Stylus, never been serviced, never had problems 

What would cause a PCM receiver to do such a thing? If I had and
intermittent signal, once the receiver did get a signal the only two
throttle signals should have been idle (PCM hold) and off (transmitter).  I
am going to send the transmitter in just to get checked. 

Thanks guys....


Gray Fowler
Senior Principal Chemical Engineer
Radomes and Specialty Apertures
Technical Staff Composites Engineering
Raytheon

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