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{\Large Pattern Trimming chart by Mike Walpole}

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This chart was set up for trimming a pattern plane.  However, there
are quite a few sport aerobatic planes that would fly better if they
were set up like pattern planes.  It's a lot easier to fly a plane
that's properly set up than a plane with all kinds of perverse mixing.
I also must give credit where credit is due, this chart comes from the
NSRCA (National Society of Radio Controlled Aerobatics) newsletter and
was submitted by Mike Chipchase of Australia.  Some of this
information is repeted from the last article on trimming for
aerobatics.

First let's talk about basic airplane setup.  The latest pattern
designs are set up with 2.5 degrees of right thrust, 0 degrees down
thrust, .5 degrees positive incidence on the wing (root and tip, no
washout), and 0 incedence on the stab.  Or, .$5 \sim 1$ degree downthrust
and 0 incedence on the wing.  Use an incedence meter to check this, or
block the plane up on a big flat table and use a scale accurate to
1/32nd of an inch. If the plans show this information use that as a
starting point. 

Control throws should be set up as shown on the plans.  It's very
important each aileron to have the same throw.  This should be setup
mechanically.  The aileron throws should be set up the same up and
down.  If the plane has split elevators make sure that each elevator
half has the same throw as the other half.  I usually set the plane up
with more down elevator than up elevator.  That way I'll have the same
control authority for up or down elevator.  Set up the rudder with
about $30 \sim 35$ degrees of throw.  Of course the ailerons and the
elevator need to be gap sealed.

To start out, the CG should be placed as shown on the plans, or about
30\% of the average chord.  The CG can be adjusted later.  Use the
placement of the radio to place or move the CG if possible.  This is
better than adding unnecessary weight because light airplanes fly
better than heavy ones.  Since the battery pack is the heaviest part
of the radio, its placement will have the biggest affect on the CG.
Also, laterally balance the plane.  Pick it up underneath the center
of the spinner and underneath the center of the tail.  Place weight on
the light wing tip until the plane balances.  Embed the weight in the
wing tip. 

With all that in mind heres the chart.

{}\hspace*{-1.25cm}\begin{tabular}{|p{18em}|p{18em}|} \hline
\multicolumn{1}{|c|}{To test for} & \multicolumn{1}{c|}{Test procedure}
\\ \hline 
\multicolumn{1}{|c|}{Observations} & \multicolumn{1}{c|}{Adjustments} \\
\hline \hline  
Control Neutrals                & Fly model straight and level\\
\hline \hline 
Trim for straight and level     & Adjust clevices to center transmitter
                                 trims.\\ \hline \hline
Control throws                  & Fly model and apply full deflection
                                 of each control in turn.\\ \hline \hline
Check the response of each control     & Aileron Hi-rate 3 rolls in 4 sec.
                                Lo-rate 3 rolls -n 6 sec.  Elevator
                                 Hi-rate to give a smooth square
                                 corner.  Lo-rate for a loop of 130 ft.
                                 diameter.  Rudder Hi-rate for stall
                                 Lo-rate to maintain Knife edge
                                 flight.\\ \hline \hline
Decalage (incidence)            & Power off vertical dive, cross wind
                                 any.  Release controls when model
                                 vertical.\\ \hline
A. Does model continue straight down & A. No adjustments\\
B. Does model start to pull out (nose up) & B. Reduce incidence\\
C. Does model tuck in (nose down)  & C. Increase incedence\\ \hline \hline
Center of gravity               & Roll model inverted \\ \hline
A. Lots of down elevator required to maintain level flight. & A. Add
weight to tail.\\
B. No down elevator required to maintain level flight or model
climbs. & B. Add weight to nose. \\ \hline \hline
Tip weight, course adjustment   & Fly model straight and level upright
                                 Check aileron trim maintains wing
                                 level. Roll model inverted, wings
                                 level.  Release aileron stick.\\ \hline
A. Model does not drop a wing   & A. No adjustment needed.\\
B. Left wing drops              & B. Add weight to right tip.\\
C. Right wing drops             & C. Add weight to left tip.\\ \hline \hline
Side thrust                     & Fly model away from you into any wind
                                 Pull into a vertical climb (watch as
                                 the plane slows down.)\\ \hline
A. Model continues straight up  & A. No adjustment needed.\\
B. Model veers left             & B. Add right thrust.\\
C. Model veers right            & C. Reduce right thrust.\\ \hline \hline
Up/Down Thrust                  & Fly model on normal path into any
                                 wind. When model is straight out from
                                 you about 100 meters away, pull into
                                 a vertical climb and release the
                                 elevator.\\ \hline
A. Model continues straight up  & A. No adjustment needed.\\
B. Model pulls to canopy (up)   & B. Add down thrust.\\
C. Model pulls to belly (down)  & C. Reduce down thrust.\\ \hline
\end{tabular}

{}\hspace*{-5mm}\begin{tabular}{|p{16em}|p{18em}|}  \hline
Tip weight, fine adjustment     & Fly the model away from you into any
                                 wind and pull into a small diameter
                                 loop.\\ \hline
A. Model comes out wings level  & A. No adjustment needed.\\
B. Right wing low               & B. Add weight to left tip.\\
C. Left wing low                & C. Add weight to right tip of remove
                                    from left tip.\\ \hline \hline
Aileron differential            & Fly model on a normal pass and do 3
                                 or more rolls.\\ \hline
A. Roll axis on model centerline & A. Differential OK\\
B. Roll axis off to the same side of model as roll command. & B. 
Increase Differential  \\
C. Roll axis off to opposite side of model as roll cmd. & C. Decrease
Differential \\ \hline \hline
Dihedral                        & Fly model on normal pass and roll
                                 into knife edge flight. Maintain
                                 with top rudder (do this test to the
                                 right and left sides)\\ \hline
A. Model does not roll out of knife edge.   & A. Dihedral OK.\\
B. Model rolls in direction of applied rudder.  & B. Reduce Dihedral\\
C. Model rolls opposite the rudder in both tests. & C. Increase
Dihedral\\ \hline \hline
Elevator Alignment.             & Fly model straight away into any
                                 wind.  Pull into an inside loop.
                                 Roll inverted and push into an
                                 outside loop.\\ \hline
A. No rolling when elevator applied. & A. Elevators correctly aligned.\\
B. Model rolls in same direction in both tests. & B. Elevator half
misaligned. Raise half or lower the other.\\
C. Model rolls in opposite directions in both tests & C. One elevator
half has more throw then the other. (Model rolls to the side with the
most throw.) Reduce the throw on one side or increase it on the other
side. \\ \hline \hline
Pitching in knife edge flight   & Same as dihedral test. \\ \hline
A. No pitch up or down          & A. No adjustment needed.\\
B. Model pitches up (to canopy) & B. Alternate cures.\\
                                & 1. Move the CG aft.\\
                                & 2. Increase the wing incidence.\\
                                & 3. Drop the ailerons.\\
C. Model pitches down (to belly)& C. Reverse the above\\ \hline
\end{tabular}

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Notes:  Trimming must be down in calm conditions.  Make mutiple tests
before makeing any adjustments.  If any changes are made go back over
the previous steps and readjust as necessary.

Well, there it is.  For the purists out there you might note that none
of these adjustments require the use of a computer radio.  A well
designed, well built aerobatic plane can be set up very close to
perfect without any mixing.  In fact that is one measure of a well
designed pattern plane.

I hope this helps any one out there that is interested learning
advanced aerobatics.

{\small
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_________________________________________________________________
 Mike Walpole     |      This space       |      msw@meaddata.com
 Mead Data Central|     accidentally      |...!uunet!meaddata!msw
 Miamisburg, OH   |      left blank!      |
(513)865-1086     |      AMA 273066       |
\end{verbatim}}

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