REFLECTOR: Pitch trim ( was Fixed vs RG)

[Dave Philipsen]

Just wanted to follow up on this previous conversation: 

I basically followed Pat's first suggestion of moving the attach point 
of the trim motor to the canard forward a bit.  Actually,  I just 
drilled new holes in the pitch trim spring and moved the bracket 
forward.  I only had to move it about 3/8 of an inch or so.  Now I have 
enough trim in either direction and at any speed.  I just made a fairly 
long x-country trip from IL to south Texas and on a couple of my 
descents I was able to easily trim for a 1000 fpm descent without 
holding any pressure on the stick.

I also reduced my takeoff pitch trim settings from 1-2 inches to 1-2 
"finger widths" and that seems to work just about right too.

Thanks for the help, Pat.



Pat Shea wrote:
> Dave,
>
> Once installed, here are some options for adjusting
> the pitch trim for more 'down' trim:
>
> - Move the bracket that mounts the pitch trim motor to
> the canard forward. To do this you will either need to
> slot or re-drill the mounting holes in the bracket.
>
> - Drill out the rivets that connect your trim spring
> bracket to the elevator torque tube, and then re-drill
> and re-rivet with the elevator trailing edge set up a
> little higher (more 'down' trim). You will probably
> need to remove your canard to do this. Also, I would
> consider overdoing this a little since it's
> real easy to add a spacer between the trim motor
> attach bracket and the trim spring if you go too far
> and need more up trim later.
>
> -Install a spacer between the trim spring and the V
> shaped mounting bracket on the elevator torque tube to
> get more down trim. A wedge shaped spacer may work
> best for this.
>
> Make sure you test for any interference issues after
> making any adjustments, specifically with the pitch
> trim spring. You will want to artificially load the
> elevator with your hands while doing this since the
> fiberglass springs moves quite a bit when loaded...  
>
> In terms of the TO pitch trim setting, try setting the
> elevator one finger's width below the trailing edge
> with one person up front and two fingers width with
> two people up front.
>
> Pat 
>
>
> --- Dave Philipsen <velocity at davebiz.com> wrote:
>
>   
>> Well, I adjusted it once already.  The guy who built
>> it had two 
>> different sets of holes where the pitch trim motor
>> assembly could be 
>> mounted.  I took delivery of the plane with it
>> installed in the lower 
>> set of holes.  I quickly realized I needed more
>> 'down' trim so I moved 
>> it to the upper set of holes.  This improved things
>> quite a bit but 
>> still left a little to be desired.  I definitely
>> have more than enough 
>> 'up' trim.  I asked the guy after I bought it if
>> he'd ever noticed the 
>> lack of 'down' trim and he said 'no'.  But he did
>> replace the battery 
>> right before he sold it to me and I wonder if the
>> new battery weighs 
>> substantially less than the old one. 
>>
>> Most people have told me to set the elevator about
>> one inch below the 
>> canard trailing edge for takeoff pitch trim with one
>> person in front.  I 
>> always do this but immediately after liftoff I have
>> to push the stick 
>> forward and start trimming down to keep the canard
>> below the horizon.

-- 
Dave Philipsen
STDFG
N171SP