E-flite Diamante 5e ARF Assembly Manual
Sequencing
Many of the trimming articles I have seen over the years
incorporate some kind of chart or graph saying do this and this
happens and so on. My concept of sequencing your trimming
is simple. If you get your trimming out of sequence you will end
up chasing your tail. As with most things in this universe, for
every cause there is an effect, and the same applies to trimming
a model aircraft. So many times I see people test flying there
now aerobatic creation, flip the thing on its side and see what
kind of knife-edge mixing it may need. Thrust, Center of Gravity,
wing balancing and basic flight control trim can all affect knife
tracking.
I can’t make this point more loud and clear—it is very important
to trim your model in the correct sequence to make sure each
adjustment has no effect on the previous adjustment.
You will see I have broken each element down, and there is
an intentional order in which I recommend to trim a model.
Model balance, Center of Gravity is number 1, differential,
knife edge flight, down line tracking will all be affected by the
Center of Gravity. Next is dynamic balancing, known as “wing
tip weight.” Then comes thrust angles, aileron differential, and
finally programmable mixing, knife-edge tracking, roll coupling,
down line track. Finally if you change your propeller, your
whole trim setup will change.
Balance
OK, how do I know what is the correct CG for my model. If
in doubt, read the instructions. Yep, chances are somebody
from the TOC or similar has designed your aircraft and has
determined over many flights, where the Center of Gravity
should be. For precision flying forward is better, but… too
far forward can be a problem. I cannot put in writing what is
the best feel for each pilot, other than it is a feel thing. I can,
however, give you some symptoms of too far back and too far
forward, plus some simple tests I do to check.
One of my favorite ways to determine the correct Center of
Gravity is spin entries. For precision flying I would expect you to
be running between 12–15 degrees of elevator throw. If you feel
you need more than this, check your exponential—it may be too
high. Just as a starting point, 35% expo is what I call a linear
feel. What I like to have with my expo is when at half stick, I get
about 50% of the reaction of full stick, around 35–40% expo
gives you this with modest control deflections. Ok, if that didn’t
make sense: If I have my stick at full travel, my aircraft will roll
around 360–400 degrees per second, about right for precision.
Now when I only move my stick halfway, I should be looking for
180–200 degrees per second. Make sense?
If when entering a spin, your model mushes, kind of slides into
the spin with no real stall visible, you may be too far forward.
Another sign of forward is excessive down elevator needed
for inverted flight. This is not always the reason but is a sign.
Rear Center of Gravity is probably easier to see for most pilots.
Model is sensitive in pitch, unpredictable around the stall, climbs
when on an inverted 45 degree line are some I have noticed.
Center of Gravity is mainly about feel, each person will have
their preferences, each aircraft will have its preferences. Be
patient, spend some time on this one, it’s important you are
happy with your Center of Gravity. I would recommend at least
10–15 flights before making the commitment to where it needs
to be if it’s a new model.
