Dan, Bruno and others,
The standing rule in aviation is all flight controls should be made to
be absolutely free from binding or potential binding. The trim T bar
for which the slot is made has a rather long moment arm, and any drag in
this area will bind/restrict/degrade stabilator control. Chapter 19
step 9 indicates the rigging de-rigging aid of two pieces of ply with a
3/4 inch gap doesn't seem elegant, but it is functional, easy to remove
for access in the event of damage or a new antenna idea. Dan and Steve
have just gilded the lily on what the book says. By adding another
access hole in the side of the aircraft you can still get access. If I
recall, Steve's allows removal of the trim T bar if necessary.
>From the building side, keep in mind the 40 hour projects to dress up a
virtually hidden slot could be spent on finishing the aircraft sooner.
>From the flying standpoint, one should not mess with the gap with any
means which would restrict trim tab control movement. I once flew a
Europa with slightly binding bushings and I couldn't figure out why it
didn't trim quite right and in the flare, when I eased back pressure the
plane would not correct back and needed slight forward pressure. Too
much if I recall was added. Thank God for tough landing gear. It was
drag in the system. Drag on the trim T bar from rubber gap sealing
strips would be even more interesting. Your pitch dampening will be
affected at a minimum as the stab will be slightly fixed from drag, and
the tiny amount of slop in the T bar system will change the tab induced
correction.
As Roger Bull from Europa once said:
"Under no circumstances should any attempt be made to close or otherwise
restrict the trim tab slot. Possible snags include icing, physical
fouling, and changes to the aerodynamics.
This latter is important since all the test flying to optimize handling
was carried out with the slot open. The airflow in this area was subject
to considerable experimentation, as it was shown to be necessary to fit
the flettner strip to achieve satisfactory elevator control, and any
change to this setup has not been shown to be safe."
So be conservative. Make nice even slots and fill the foam edges, sand
smooth and fill, fill, fill until nice.
Just my thoughts,
Bud
----- Original Message -----
From: UVTReith<mailto:uvtreith@t-online.de>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Monday, January 26, 2009 8:58 AM
Subject: AW: Europa-List: Elevator Trim Tab slot.
Woh, Dan
That's looks complicated and it seems to me that there will be still a
lot of drag.
Why not just using the brush side (inner part) of a door seal or
similar? Just cut it in lengths and clue it on both inner sides of the
fuselage to seal the T-bar rod ends.
This is cheap, clean and the weight is nearly nothing.
Have a nice day,
Bruno
-----Urspr=FCngliche Nachricht-----
Von: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] Im Auftrag von danbish
Gesendet: Montag, 26. Januar 2009 14:04
An: europa-list@matronics.com
Betreff: Re: Europa-List: Elevator Trim Tab slot.
Actually, I got busy this morning and put the photos up already. Let
me know if you have any questions.
Click (or cut and paste) here:
http://www.europaowners.org/modules.php?set_albumName=T-Bar-Slot-Mod&op
=modload&name=gallery&file=index&include=view_album.php
Dan
Visit - www.EuropaOwners.org
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avigator?Europa-List>
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