84 M ODEL AVIATION
As A yOung man, I played a gentle English sport called rugby. As
that same young man, I tried to build a jet turbine (and failed
disastrously). Undeterred, I built Jetex gliders once my father had
forgiven me for almost burning down his workshop.
Within budget constraints, I then dallied in diesel engines and
really got into glow engines. These engines took me from Free Flight
to Control Line (CL) Combat, and eventually into the wonderful
world of Radio Control (RC) flying.
As a much older man with seven children, I had hoped that one or
two of them would follow in my footsteps. “Be careful what you wish
for,” as the old Chinese saying goes.
My eldest daughter is playing rugby for her college in
Massachusetts. How the times have changed! I’m very proud of
her efforts, but I can’t bring myself to share my old rugby
“shanties” with her!
My eldest son will graduate this year from engineering college
in upstate New York. He almost got into airplanes, but had more
fun with RC cars.
Enter my youngest son, who is 15. He came to live with us
soon after I remarried. We were empty-nesters for approximately
a week, then he “arrived”!
After four weeks of stick time on my wife’s O.S. 40 FSR-powered
trainer and the personal-computer simulator, he was up there flying
solo. This is almost the best an RC dad could have it—or is it?
He had not been soloing for more than a week when he began
surveying my Pattern airplanes. “Hey dad! You don’t seem to use
these planes much; how about I fly one of those next?”
My Hydeout and Sequel were in his sights.
Panic set in as I searched for a way to deal with what I had wished
for. I spluttered a few weak explanations, such as, “it’s too cold here
Eric Henderson, 303 Shady Ln., Marlton NJ 08053; E-mail: [email protected]
RADIO CONTROL AEROBATICS
Linda Carnes and her Tai Ji 60 with YS 91 engine.
Linda Carnes looking very happy and proud at her first Pattern
contest with the new Tai Ji Almost Ready-to-Fly model.
“Number 2 son” Robert Henderson, partially “constructed” Tai Ji 40.
86 M ODEL AVIATION
to fly them in the winter,” “you need to practice much more before
you ever … ,” etc.
Here I was, with an enthusiastic son who wanted to fly
Aerobatics just like his dad (hopefully better), and my Pattern fleet
was in imminent peril.
Then I remembered the column I was writing about Linda Carnes
and her Tai Ji Almost Ready to Fly (ARF) adventures (which I will
get to in a few sentences). She began flying Precision Aerobatics
since she is no longer as active in full-scale flying.
Linda wrote to me with details about her experiences with an
ARF, which linked well to some suggestions in previous columns. As
a direct result of her letters, number-two son is roughly halfway
through completing a 40-size Tai Ji.
The ARF itself was not too expensive compared to my mainline
Precision Aerobatics airplanes. However, after buying a few servos, a
receiver, a flight box, etc., I may be invited to the Creek Hobbies’
owner’s family Christmas dinner!
What caught me by surprise was the time I would have to put into
teaching my son all the things I do habitually when I build a model.
It is amazing how anal-retentive a person can become when he
or she specializes in something. It was extremely hard not to insist
on perceived perfection. I caught myself taking over my son’s
project, and I had to apply the emergency “coach’s” brake to let
him build it on his own.
Even ARFs can attract the attentions of a bona fide Pattern fanatic.
Thanks to Linda Carnes, because her successes with the Tai Ji
gave me the concept. We opted for the smaller version for my
son, because of a spare engine I had (an O.S. .32) and the size of
“his” workbench.
Now I am in the position to test what has been promoted in this
column; it is my turn to take my own medicine. I will keep you
informed about how it goes with my “rookie” son.
Linda wrote to me several times, and I have assembled a
compendium of her information. Her’s is not the only way to go, but
she does support the approach of getting a good-flying almost-
The very bright graphics on the 40-size Tai Ji’s wing should help
with the Sportsman pilot’s orientation in the air.
This sign should hang in all fliers’ workshops.
88 M ODEL AVIATION
ready-to-go airplane that is purposedesigned
for Precision Aerobatics.
Let’s look at all the costs. This ARF is
fairly competitive, and should be balanced
against what it takes to put a 60- to 90-size
aircraft in the air.
Following is a breakdown of the
investment Linda has in her Tai Ji 60:
World Models Tai Ji 60 ARF kit,
$400; six Futaba 9101 servos, $300;
Futaba eight-channel PCM receiver,
$180; Falcon Hobbies tuned pipe and
mount, $200; carbon rods, 5/32 piano
wire, Great Planes axles, fuel lines, fuel
fittings, strapping tape, Sullivan Head
Lock, and servo extension leads, $100;
Hayes fuel tank, $4.99; Tru-Turn 23⁄4-
inch spinner, $25; APC 14 x 10
propeller, $10; YS 91FZ engine, $270;
custom graphics for her name and AMA
number, $40.
This gave Linda a grand total of $1,525.
It’s surprisingly comparable to a good sport
airplane, engine, radio, etc.
You probably noticed a few items on
the list that the kit would normally have
provided. I noticed an early trend toward
wanting to have the “better” accessories
and parts—a common trait in Precision
Aerobatics pilots.
You could easily fly this airplane on a
$200 five-channel radio and knock the
investment down to approximately $950.
Not that Linda should have gone that way,
but you can perform well without all the
super goodies.
I would have used a Hayes tank; I am
familiar with them, and they hold the five
to nine pounds of pressure of a YS fuel
system very well.
I would have used the carbon rods and
roughly another $100 of ball-race
connectors and a carbon-fiber pipe.
Purchasing a $50 muffler from AAP
would also get you into the air at a
respectable noise level.
Linda went on to report that she
relocated the fuel tank to one inch behind
the center of gravity. A 1,400 mAh battery
and receiver are in front of the tank.
She used green and red cable ties on
two of three servo extension leads, to
make sure she got the left and right
aileron and the gear connected properly
each time she put on the wing. It could
be nasty if you retracted the gear and did
a slow roll on takeoff.
(Most computer radios allow you to use
a channel for each of the aileron servos. If
you get them crossed, you could reverse
your ailerons or flap action.)
Linda used two check valves inside
the engine cowl, to prevent pressure
from backfilling the engine at idle—a
common problem she had with YS 91s
mounted inverted.
Also inside the cowling is one fuel dot
on the vent side and one fueling valve on
the fuel side, to prevent flooding the
engine during fueling.
Linda also wanted me to see that she
used blue lines for vent and pink for fuel.
Using a Sullivan Head Lock for the remote
glow-driver allows her to connect into the
side of the airplane, and keep her hands
clear of danger. She also thinks it is much
easier and better than cutting a hole in the
cowl for a glow-driver.
The throttle linkage is Sullivan cable
with 2-56 ends soldered to it, and 2-56 ball
swivel links. It’s a pain, but well worth the
effort—especially on a YS in which
precision throttle position at idle is needed.
The throttle servo is a Futaba 9101.
Linda used small pieces of fuel line to
make the high-end needle valve resistant
to vibration, then she then drilled out the
end of the needle valve and inserted a 2-
56 hex-head screw.
Linda uses a hex wrench for needlesetting
adjustment; this leaves nothing
sticking out of the airplane that will cause
drag or get bumped accidentally.
The air intake was increased from
roughly one square inch to almost three
square inches, to improve the cooling of
the YS 91FZ.
Linda replaced the gear, because the
original was too soft a grade of wire.
New legs were made from piano wire and
Great Planes axles. She replaced the thin
wire pushrods with carbon-fiber rods on
the ailerons, because the original 1.8mm
rods bent during flight.
Linda informed me that she had sent in
her National Society of Radio Controlled
90 M ODEL AVIATION
Dupe color plate
for true red
Film/Matchprint
provided
Envelope 90
Aerobatics (NSRCA) membership
application the week before. Articles in the
NSRCA’s K-Factor publication tend to be
much more technical, and should help her in
her future successes as a competitive RC
Precision Aerobatics pilot.
Linda is a member of the very exclusive
1% club; according to her, only that
percentage of the AMA membership is
women. Or was it NSRCA? Either way, I
hope that reporting on her endeavors will
encourage more women to give it a try—or
at least encourage all the men to sponsor a
woman and encourage her to give it a try.
Thanks again to Linda for taking the
time and making the effort to let us all know
about her and her Tai Ji.
takeoff: Perhaps this should have been the first
maneuver, but it seemed more appropriate to put
it in later since it is not really an in-flight
activity. It is not easy to get perfect, but the
rewards of meeting this challenge are visible.
This maneuver has more written about it in
the rule book—second only to the landing—
than any other. It is scored for precision in
AMA Precision Aerobatics classes 401 to 404.
The takeoff is often considered the mark
of a Pattern flier—how well he or she can
make the airplane execute this maneuver.
Read the AMA Competition Regulations
to learn the current rules for all the
maneuvers covered in this column. The
takeoff has many criteria.
If you do not have a manual, contact
AMA and ask for a copy. You can also
find this information on the AMA Web
site: www.modelaircraft.org. Select
“Competitions/Technical Department,”
then select “Competition Regulations.”
The big deal about a precision takeoff is
that you control the airplane leaving the
ground in the manner you want it to, as
opposed to how it wants to. The model will
have a “natural” way of wanting to leave
terra firma. We want to harness this, and
make the aircraft perform within a set of
measurable parameters.
Precision Aerobatics pilots often draw
great approval from the “peanut gallery”
when they get an airplane to leave the
runway in an exact and smooth manner.
The first thing you notice is that the
airplane is guided from a downwind
position parallel to the line of the runway
and the pilot. If there is a centerline on the
runway, the pilot will follow it.
Many sport pilots gained their wings by
standing behind the airplane and “gunning”
the throttle. This habit has persisted
throughout their flying careers.
A precision takeoff is a challenge; not
only is the airplane coming toward you,
across your center, then away from you, but
the wheels are doing their best to grab at
each blade of grass. The engine’s torque
will make most models veer off to the left,
and will require rudder correction.
The ideal takeoff is a smooth
acceleration in a straight line parallel to
the flightline. The airplane should leave
the ground at roughly stage center, and
climb out in a shallow, straight line. The
wings should be level, and the model
should not abruptly point its nose into the
air at a steep angle.
Advancing the throttle and
accelerating smoothly are actually not the
same actions. You may need to apply a
great deal of throttle to get the airplane
moving. You should not just slam the
stick forward and hang on.
Steering the airplane with the rudder is
an art in its own right. The problem for most
airplanes/pilots with ground-steering is that
the normal in-flight rudder throws are often
too great for smooth ground handling. The
trick is to use dual rates that considerably
reduce the steering effect during takeoff.
A 50% reduction of throws is often what
is needed to prevent your rudder inputs from
causing the airplane to do an impersonation
of a squirrel crossing the road indecisively!
Many computer radios allow you to have
an auto dual rudder rate that is linked to the
throttle. At medium or above, the rudder
low rate is turned on. The thinking is that
you will only need full rudder throw in Stall
Turns, Spins, etc., where the throttle would
be pulled all the way back.
Another way is to use a significant
amount of exponential on your rudder. You
would set it up so the stick was “soft” near
center. This would make the rudder less
sensitive to your inputs while you were
performing a Takeoff, but fully available to
you in the case of a Snap Roll, Spin, Stall
Turn, or knife-edge.
The exponential method also prevents
that “Oh! I forgot I was on low-rates”
moment, when you try a rudder-related
maneuver. The most certain way to forget a
setting switch is to have it there to forget in
the first place. Competition pressure will
erase all memory without warning.
To add more pressure when you try a
competition Takeoff, you have to
announce to the world that you intend to
attempt it with something such as,
“Takeoff beginning now.”
Then you perform it with everyone
watching and last you announce, “Takeoff
complete!” Not announcing can cost you
two points of 10.
Please take time to try doing this
maneuver right. Get that “friend” to
evaluate your takeoffs. It is so hard to see
how you are doing because of the relativity
of the ground, and how it rushes by.
Now that you know what you are
trying to achieve, you will soon get a
sense of success. Before long, you will be
the one “they” watch!
“Takeoff complete.”
P.s.: Please don’t forget to sponsor your US
team. It will take off for Ireland in 2001.
The US is the defending world FAI
Aerobatics team champion. Your donations
will help us do well again. MA
