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

[krishlan fitzsimmons]

Gray, 

I also fly Stylus's and I haven't seen this problem. But, I also keep my radio's in good health with checkups at Airtronics. I recently sent one in before the nats and they found lots of little things that needed repair. It is of great importance with any radio and receiver that they are checked out no more than every 3 years or so (imo) to make sure the module and receiver are tuned and also to look everything else over. 
BTW, your radio should get a new 3 volt battery every two years. 
 
The problem you are describing could be a bad crystal, or possibly a low battery. I had one ship go in a few years ago that I decided to fly 8 1/2 (was shooting for 9, lol) flights on. The Tp 730 pack didn't last into that last flight. The voltage would get a little to low, and I would have no control for a second, then I would let off the controls, and the voltage would go up a little, and then I would have a small amount of control for a second. Did this several times. Sounds kinda like what you may have gone through. Needless to say, I lost my plane also. 
My battery checked out ok though, but not under load. It was under by far then. 
 
Chris


Chris 
 
 
 

--- On Tue, 9/2/08, Gray E Fowler <gfowler at raytheon.com> wrote:

From: Gray E Fowler <gfowler at raytheon.com>
Subject: Re: [NSRCA-discussion] Ideas on radio beserkness-cause of crash??
To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>
Date: Tuesday, September 2, 2008, 7:01 AM



Tx battery totally fine 10.3 volts at crash...new pack was cycled and tested. I do not understand a low battery failure...From what I have seen with batteries either you got it or you do not. 




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






vicenterc at comcast.net 
Sent by: nsrca-discussion-bounces at lists.nsrca.org 
09/02/2008 08:44 AM 




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Gray, 
  
Sorry about your lost.  It think the biggest chance of failure were those parts that were new.  I think there is a good chance that you have infant battery failure.  I know that the chances are low but it could happen.  I assume tha you checked the TX battery and it is OK.   
  
--
Vicente "Vince" Bortone 
  
-------------- Original message -------------- 
From: Gray E Fowler <gfowler at raytheon.com> 

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 mo re con trol. 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 i dle (P CM 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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