REFLECTOR:Pitch Trim Spring

[Dave Nelson]

I've actually had quite a bit of fun getting a satisfactory pitch trim
system up and running on my velocity STD-RG.  The situation is as follows...

First, I started out with the standard "per plans" installation of the
fiberglass spring mounted with the loop at the top.  After a few years of
financial recovery from building the airplane, and because I'd earned my IFR
in my Velocity, I treated myself to an upgraded panel (the Apollo
stack -very nice!).  There were clearance problems with the per-plans pitch
system, so I wound up reversing the fiberglass spring by putting the loop at
the bottom.  This created enough clearance for the radios but had inadequate
pitch trim authority in one direction.  I tried beefing up the fiberglass
spring with more bid and even carbon fiber, but in the end the trim
authority was (a) inadequate for pitch up trimming, and (b) non-linear in
response.  So, last winter, I went to the effort of replacing it with a
whole new system.

Working with Alex Strong, we came up with a modification of his pitch trim
system design, which is pretty much standard in Cozys and Long-ez nowadays.
The new system mounts in my center section counsul (remember, STD-rg), and
attaches to the bottom of the stick from aft of the stick. After about 35
hours, I can report it works very well.

I plan to write this up for Velocity Views (and the newsgroup) if anyone is
interested.  If you can't wait for details, just drop me a line.

Dave
----- Original Message ----- 
From: "Alex Balic" <alex157@direcway.com>
To: <reflector@tvbf.org>
Sent: Sunday, May 16, 2004 10:54 PM
Subject: RE: REFLECTOR:Pitch Trim Spring


> The pitch spring needs to be stiff like that because during flight it is
> constantly holding the "elevator"/flap down, and during flight you really
do
> not need much deflection at all to change pitch, more is required during
> landing, but you can overcome the spring with some more pressure, and trim
> position.   I would recommend that you do not trim it at all, and wait
until
> you have finished flight testing to make any adjustments of that kind..
You
> can't look at it like it is an elevator on a conventional airplane,
because
> it is not.
>
> -----Original Message-----
> From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
> Behalf Of NMFlyer1@aol.com
> Sent: Sunday, May 16, 2004 10:21 AM
> To: reflector@tvbf.org
> Subject: REFLECTOR:Pitch Trim Spring
>
>
> I recently rigged my elevators and attached my pitch trim. The pitch trim
> force seems quite high. I know that the trim spring can be trimmed to get
> the force that you want. What I don't know is what force would be
> comfortable in the air, and how much more stiff the system feels with an
> airload.
>
> Any words of advice from those flying?
> I have the 173 FGE.
>
> Kurt Winker
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