REFLECTOR: Pitch trim malfunction

[aminetech at bluefrog.com]

Scott,

That's a VERY good question.  It reminds me of a pitch up due to an area of convective rise.  Generally in these cases I can force the nose back down.  Today I pushed hard and the nose didn't come down until 3-4 seconds of down trim.  But maybe that was just a larger than normal convective rise.  Does this describe your experience?  On the other hand, I've only experienced this in recent months and not in the 7 1/2 years of flying previously.

John

--- scottb33333 at gmail.com wrote:

From: "Scott Baker" <scottb33333 at gmail.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Subject: Re: REFLECTOR: Pitch trim malfunction
Date: Thu, 5 May 2011 19:39:29 -0400

John,
When flying Velocity aircraft I have often experienced a pitch up upon 
entering clouds or precip - and of course when entering an area of 
convective rise activity - to the point where pitch 'down' trim is needed. 
Soon thereafter the flight situation will call for pitch Up trim.  Might 
these describe what is happening to you?  Or do you feel the pitch trim is 
actually running away?
Scott B.


----- Original Message ----- 
From: <aminetech at bluefrog.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Thursday, May 05, 2011 6:39 PM
Subject: REFLECTOR: Pitch trim malfunction


> Several times a few months ago and another time today, it seemed like my 
> pitch trim trimmed up uncommanded.  I had to apply forward stick pressure. 
> After a few seconds of pressing the down trim button, the stick pressure 
> went away.  I have the MAC G7 stick.  I have solid state relays.  In the 
> past the up trim relay failed and I had to land with the trim stuck in the 
> full down position.
>
> My questions are:
>
> 1) What can the cause be?  A stuck button on the stick?  A malfunctioning 
> relay?  The trim motor?
>
> 2)  Would one of the above failure modes result in shorting out the trim 
> circuit when I press the trim down button?  If so, then that failure mode 
> can be eliminated since a short does not happen.
>
> 3)  Is anyone using this stick without relays?  Maybe I could eliminate 
> the relays and make it simplier.
>
> Thanks,
>
> John
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