Radio Control Pylon Racing - 2011/04

120 MODEL AVIATION
WE ARE DEEP in the heart of winter here
in the great state of South Dakota, not unlike
most parts of the Pylon Racing universe.
Spring is not too far off, though; soon races
will be filling up our calendars and
adrenaline will fill our veins.
This month’s column is intended to spur
some thought about how you will get around
the pins faster and more consistently in
2011. I hope that these topics will also help
increase your fun-per-race ratio this
upcoming season.
Flying the Course—Fast: Now is the time
to be thinking about how to make
improvements on the course this season.
One area that can pay dividends in the form
of lower times is learning about the physics
of Pylon models.
Before you skip to the next section, let
me try to reel you back in. I promise not to
go all engineer on you and get
ultratechnical. Basic knowledge of
aerodynamics will help by offering a few
more speed knobs to think about and
perhaps dial in.
Martin Hepperle’s Aerodynamics of
Model Aircraft Web site contains some
excellent information related to the physics
of racing model aircraft. He takes a deep
technical dive on airfoils, engines,
propellers, and a number of other interesting
topics. I highly encourage you to check it
out and absorb as much information as you
can.
Go to Martin’s site and double-click on
the “Index” tab near the upper left corner of
the home page. Select section “E.” Under
“engines” and “models,” choose “pylon
racing (F3D).”
Click on “A Comparison of Pylon
Racing Airfoils.” Near the bottom of the
Look—race season is on the horizon
[[email protected]]
Radio Control Pylon Racing Aaron “AJ” Seaholm
Above: Near to far, Dub Jett, Randy
Bridge, Matias Salar, and Richard Verano
demonstrate launch styles at the 2008
NMPRA Championship race.
Below: Dan Kane designed and built this
beautiful Shoestring for the emerging
Electric Formula 1 class.
Left: Travis Flynn at ful l extension,
launching the late Fred Burgdorf’s Proud
Bird in Phoenix, Arizona. The launch is
critical to a team’s success in RC Pylon
Racing.
04sig4z_00MSTRPG.QXD 2/22/11 11:51 AM Page 120
page is a section titled “Pylon Racing
Simulation.”
This study seeks to determine the ideal
Pylon Racing course shape, think overhead
view, from a mathematical physics model
standpoint. The mathematics take into
account lift and drag profiles, turning radii,
and a host of other variables. The study
concludes that a course with equal-radii turns
between unarcing straightaways provided the
lowest times for a given lift coefficient.
After observing hundreds of heats flown
by the fastest pilots in the country, I will add
a slight variation. I do not have the cool math
to back it up, so you will have to trust me.
A slightly arced line from Pylon One to
Pylon Two can also help trim off some time.
This is primarily because of the decreased
angle through the turns where induced drag
is very high.
Think about it like this. If a model enters
Pylon Two at a 90° angle to the line between
pylons two and three, it will turn for 180°
before exiting back toward Pylon One.
During that time, the induced drag, a
byproduct of the lift required to make the
tight turn, is decelerating the airplane.
Therefore, if you can slightly round off
the straights, you can decrease the angle at
which the model enters the turn and decrease
the angle required to get it pointed back
toward Pylon One. This minimizes the
distance in which the model is slowing.
If you do not consistently fly the arc from
Pylon Three to Pylon One every lap, you put
your caller at a huge disadvantage because
the model travels a different distance each
lap. Adjusting for slight changes in distance
flown can make the tough job of calling
nearly impossible. Therefore, I attempt to
fly as straight as possible from Pylon Three
to Pylon One, to give my caller the same
distance traveled each lap.
In practice you have to be careful with
this concept. It has been my experience that
newer racers tend to make the arc too wide
down the straights.
That comes from the pilot’s location in
the center of the course and the extremely
uneasy feeling generated from the model
flying back at him or her from Pylon One.
This leads to the pilot’s releasing the turn
early at Pylon One and naturally creating
the slightly egg-shaped line between Pylon
One and Pylon Two.
If you try to teach the slightly arcedshaped
course, the less experienced pilots
will let off of the elevator even earlier at
Pylon One. The extra distance traveled in
the straights then overshadows the benefit
of the reduced drag angle through the turn.
The method I have used with success is
to have the new pilot envision Martin
Hepperle’s ideal course with the two 180°
turns with unarcing straights. This typically
leads to a course that is closer to ideal than
coaching the student to gently arc the
straights.
Keep in mind that the time-saving
techniques I described earlier can be blown
away by missing your Pylon One turn. To
drop your times to fast guy and fast gal
territory, Pylon One will pay the largest
returns for time reduction.
Why, you ask? Simply because the
distance by which you miss Pylon One is
multiplied by a factor of 2. If you fly 100
feet past Pylon One, you also have to fly
100 feet back; you just added 200 feet
traveled for that lap.
Again, this is where the pilot/caller
relationship is so important. Find a good
teammate, occasionally buy him or her
dinner, and treat that person as a valued
piece of your Pylon Racing endeavor.
Art of Calling—Launching: The launch in
an RC Pylon Racing heat can really make or
break the standings on lap 10.
If you, as the caller, are late or do not
provide a straight, forceful launch, the rest
of the heat can be an uphill battle. Being
late on the push will place your pilot
squarely behind other racers, who will
provide many of those giant holes in the air
to dodge.
Scott Causey and I have adopted the
sprinter’s-position launch technique. Travis
Flynn, Gary Schmidt, Randy Bridge, and
others have used this technique with great
success. Watching this launch style from
the sidelines usually makes its benefit
apparent, as their pilots’ models come
catapulting into the lead.
It takes awhile to get the hang of the
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position. But once it’s mastered, this style
will provide a great deal of consistency and
velocity out of the hole during launch.
The other benefit of this approach is that
it tends to keep the push parallel to the
ground for a longer stroke of the arm.
Rather than a swinging motion of the arm,
you get an extension motion.
That keeps the tail from coming up and
buzzing the propeller—another mistake
mode that can often lead to a 3- to 4- point
meltdown heat. Been there; done that.
Find a launch position that is
comfortable, and focus on becoming
consistently quick with your stroke. Your
pilot will thank you.
Staying the Course—To Move or Not to
Move: In the February 2011 column I
introduced the Conservatively Aggressive
Game Plan concept. Another element to this
concept is “Staying the Course—To Move
or Not to Move.”
If you talk to most experienced Pylon
racers, they will tell you to hold your line; if
you move, that is when a midair will
happen. My approach to “holding your line”
has a slightly different and more
conservative spin, to help protect that
substantial racer investment.
Having blasted many Combat models out
of the sky before my re-entry into Pylon
Racing, I began to recognize midairs
coming. I will not claim that I was able to
avoid them, but when two models go in for a
kill on an intersecting flight path, boom! Big
wreck.
It is the same in RC Pylon Racing. If you
try to fly the same line as your competitor,
you will eventually try to occupy the same
space. Pylon racers occupying the same
airspace rarely ends well.
With this little pearl of wisdom, why
would you hold a line that might be the same
line as your competitor? There is plenty of
vertical airspace on the course. Why not take
advantage of it and reduce your racing
expense?
Choose a line above or below your
competitor’s flight path. Then hold your line
by controlling your vertical spacing, and
duke it out for 10 laps of clean side-by-side
racing.
An integral part of picking a line is the
knowledge of your competition’s flying
style. I prefer 10-15 feet above the top of the
pylons as the lead line. If you can get the
lead, you will get to pick the line, and those
following will need to slide up or down to
avoid bad air.
Your competitor’s line will change with
time and experience. Newer racers will not
hold lines as consistently, which usually
provides you with openings to get around them.
Ideally I prefer to pass at Pylon One,
because my field of vision is much greater.
For me, between pylons two and three is the
most challenging; as you turn your head
through this turn, your field of vision is
limited. This makes it easy to misjudge
where your model is and fly directly into a
competitor while trying to squeeze past.
All of this sounds good in theory, but it
will not provide much benefit until you can
hold your line and fly consistently. So log
those simulator laps and get in as much race
stick time as you can. Race stick time adds
the adrenaline factor that you cannot
replicate any other way.
EF1 Update: The Electric Formula 1 (EF1)
crew has been hard at work.
Dan Kane sent in the picture of his new EF1
Shoestring, taken at the 2010 NMPRA
Championship Quarter 40 race held last fall in
Phoenix, Arizona. That is one fine-looking
model.
Have fun and race hard! MA