I’d like to write a monthly column that
addresses the more technical side of our
hobby. I am probably more addicted than
most, but I really enjoy the how’s and why’s of
our toys and would like to share as much as I
can with you. I take great pleasure in tweaking
whatever project I am working on to get the
most performance out of it whether it be radio
setup, or getting an engine to run perfect or
dialing in C.G and control throws. What I
would really like is for people to submit a
question or topic that they may be interested
in, and I could write about it here. Some
columns may go hand in hand with a live
demonstration at our monthly meeting,
perhaps something like an introduction to
composite part making or other relevant
topics.
To get the ball rolling I thought I would touch
on some radio basics that there still seems to
be some confusion about, and some
reluctance to use. There really is no excuse
for not using whatever features your radio has
to offer. Even the most basic aircraft can
benefit from some of the advanced features
that even the mid level radios seem to be
equipped with nowadays. My goal here is to
hopefully explain some of those features a bit
better and inspire some to give it a shot.
Most people don’t realize that the ergonomics
of your transmitter can be changed quite a bit
to suit your flying style fairly easily. For
instance, the control stick length can be
adjusted to a more comfortable position. As a
“pinch” type pilot I prefer my sticks very short.
If you are a “thumber, you might like them a bit
longer. If you tend to be a jumpier flyer, longer
sticks can smooth you out and conversely, 3D
pilots generally like them shorter. The point is
you might not realize what you are missing, so
tweak them and find out. Another stick related
item is tension. Many radios allow you to
tighten or loosen stick tension to suit your
style as well. Jumpy/precision guys like
tighter, 3D looser. I prefer them on the tighter
side. Your switches can also be rotated
slightly in the case to be less cumbersome to
flip depending on whether you pinch or thumb.
The best switch flipping path may not always
be straight up and down.
Another area to look at is exponential, or expo
for short. I know, I know seems mundane but
in reality it seems to be a bit misunderstood
underutilized. Just recently I helped a fellow
member adjust expo values with favorable
results and that got me to thinking it’s not as
widely used as I had assumed. What expo
does is essentially “soften up” the movement
of the control surface in relation to the
movement of the stick around the neutral point
of the controls. This is needed because of the
way our servos act our flight surfaces. The
servo takes rotary motion (the twisting of the
servo arm) and transfers it to linear motion
(back and forth of a pushrod). This inherently
causes some loss of throw as you reach the
ends of the travel as the pushrod moves less
back and forth and more in towards the center
of the servo. In fact if you do not use any
expo, a standard set up will actually have
negative expo and be more jumpy around
neutral! A good rule of thumb is that it takes
20-25% expo to get back to a linear motion. I
never use an expo value of less than 35% on
low rate and as high as 60-70% on some
models. My racer runs about 45% on all
surfaces. Give it a try; you might be in for a
treat. (Ed. Futaba uses the opposite
numbering for this feature, negative values
result in a softening of the controls. If in
doubt, ask someone for help)
I’d love to hear from you. If you guys find any
of this stuff helpful drop me a line. I take
requests.
Email Red at
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with your comments and suggestions.
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