104 MODEL AVIATION
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Radio Control Aerobatics Eric Henderson
Also included in this column:
• Thoughts about the 2.4
GHz revolution
If you are new to RC Aerobatics, you might need a stepping-stone model
Top and Left: Eric’s 40-size Hangar 9
Ultra Stick. The 60 size would also be a
good “stepping-stone.” The color scheme
is striking, and the asymmetry could be an
asset for orientation after snaps and spins.
MANY RC PILOTS’ mission is to improve
their aerobatic flying skills. A common
belief is that you have to fly an Aerobatics
(Pattern) airplane to learn and perform
aerobatics.
I often review models apart from this
column that are not specifically designated
as “Pattern” airplanes. I also build a large
number of sport aircraft for myself and
members of local clubs.
Those models keep me in touch with
what pilots at a typical “local field” are
buying. Flying all those different designs
also often reminds me of the differences
between Pattern and sport airplanes.
On the surface the current sport ARFs
tend not to show their potential as really
good Pattern models. It is not obvious by
just looking at them what is underneath the
surface. More times than not there is little
difference between the aerobatic capabilities
of a sport airplane and a Pattern airplane.
It is common logic that you need a
purpose-built and/or -designed Pattern
airplane to fly precision aerobatic schedules
and maneuvers. This logic misses a huge
step in pilot development.
There has to be a time when you learn to
fly. It logically follows that there has to be a
phase during which you learn to fly
aerobatics. Another stage is when the rudder
has more function than just steering on the
ground. Then there is a phase in which you
take command of your airplane and put it
exactly where you want it at all times!
Logic is a good process, but it is not law;
we can easily challenge the concept of using
a Pattern model to learn aerobatics. How
about inserting the need for a stepping-stone
airplane? It would be relatively inexpensive,
easy to fly, and capable of aerobatics. It
would not have to qualify for precision
Aerobatics competition. In this logical
progression you are not there yet.
A huge number of sport and Scale
Aerobatics airplanes can be used as this
stepping-stone. You can use these to
develop your aerobatic skills long before
you are ready compete or spend your hardearned
cash on a competition aircraft.
The stepping-stone logic allows you to
consider a whole series of readily available
ARFs. You may already own one that can
more than satisfy your pre-Pattern desires
and needs. You can also choose an airplane
because you like the way it looks or how it
fits your budget.
A popular sport model is the Hangar 9
Ultra Stick. It comes in several sizes to meet
different budgets. I recently put together the
40-size versions for an AMA Sport Aviator
online review.
This model is inexpensive, and an
Evolution .46 engine will pull it straight up
and out of sight. It flew well with lowercost
“standard” servos. They provided all
the accuracy and guidance required.
The Ultra Stick comes with several
aileron/flap options but could be built as a
fully aerobatic four-channel model. Not
only did it go straight up, but it tracked
straight in the loops and did great Slow
Rolls and Four Point Rolls.
You have a unique opportunity to see
this airplane fly on the Internet. You can
look up the Ultra Stick review at www.ma
sportaviator.com. This AMA-sponsored
Web site is free to all-comers. The reviews
there often contain downloadable video
clips of test flights.
One of the clips shows the Ultra Stick
doing extremely slow Rolls with no
problems at all. It has great performance for
a sport model. It means you can learn to do
Slow Rolls with an airplane that will be on
your side! You could easily use this model
to hone your precision aerobatic skills.
When asked to do a Spin, the Ultra Stick
was easy to get to enter and exit on
command. It is also a friendly airplane to
take off with and land precisely. Snaps were
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July 2007 105
Bill Brennan’s Great Planes Pitts Special. The full-scale version
is a world-famous aerobatic airplane.
There would be no problems seeing the Pitts Special while it
performed an Aerobatics maneuver or schedule.
The Hangar 9 ShowTime looks like a Pattern airplane without
its side force generators. If it quacks like a duck ...
Bill Brennan with his new Great Planes Ultimate. It’s a capable
Aerobatics model. Is it a good Pattern trainer?
pretty and acceptable. The price is right, and
the best part is that you do not have to do
anything special to get one to fly right!
It is probably fair to say that all Pattern
models are designed to make aerobatics easier
in one way or another. The key to choosing
the right stepping-stone airplane is to find one
that does not need you to develop
considerable unnecessary “extra” piloting
skills to make it perform well.
There are no real restrictions in this Pre-
Pattern logic. You could consider several of
the scale biplanes out there. Some Pattern
biplanes are currently competing at the World
Championships level.
If you like a larger biplane, the Great
Planes Ultimate is excellent with super
handling. The model I finished and tested
sports an O.S. BGX engine turning a Mejzlik
20 x 8 propeller. This potent combination
easily allows you to do all maneuvers up to
and including those for FAI international
competition.
The Ultimate is a pre-Pattern airplane
because it is too big and too heavy to meet the
Aerobatics rules. But this is not a problem
because we are working on our aerobatic
skills, so we can fly the pants off of it with
impunity.
Are there sport airplanes that are the right
size and weight for aerobatics competition?
The Hangar 9 ShowTime meets all Patterncompetition
size and weight specifications.
I built a ShowTime this year and grafted
an O.S. 1.08 onto the front. This combination
has tons of power but was perhaps a bit on the
loud side for competition.
However, that need not be a big concern,
even if you intend to try a Pattern contest with
this combination. Pattern event CDs really
want you to come to their events. It is
common practice for them to waive the
Pattern-contest noise requirement in the
Sportsman (AMA event 401) entry-level
class. They want you to try competition and
hopefully get serious later.
As long as you meet the host club’s
standards, the event directors usually invite
you to fly your “sport airplane.” It can’t hurt
to pick up the phone and ask. Once you attend
a contest, you will learn more than I could
ever write here.
If you want a model that looks and sounds
a bit more like a Pattern airplane, the
ShowTime would be perfect with something
such as a YS 1.10 engine or electric motor for
power. The four-strokes tend to be quieter
with a standard or aftermarket replacements.
The ShowTime I built and tested flew
great once I moved the CG forward
approximately 1/4 inch from the
recommended 3-D position. The supplied side
force generators were not fitted. The model
weighed more than 8 pounds.
It went straight up with no help from the
transmitter. It needed only a teeny bit of
down-elevator-trim mix at the low-throttle
setting to correct a down-line pull to the
canopy.
Axial Roll performance was easy to
extract from the ShowTime. Only small
amounts of rudder input were required to
keep the nose up on a Slow Roll. Knife-edge
flight was excellent, so the first and third
points of a Four Point Roll could be held with
comfort.
I must accept that the “comfort” is backed
up by the accumulated opinion of a set of
07sig4.QXD 5/23/07 9:38 AM Page 105
“experienced” hands. If we get back to the
goal of learning how to do great aerobatics,
we can predict that “new” hands would learn
much more quickly if there was an immediate
positive result from rudder input.
The ShowTime did many things well. It
entered Spins with authority and would do
them with rudder and elevator inputs only.
The best part was that the spin would stop as
soon as the controls were returned to neutral.
This would let a pilot quickly learn how to
stop a spin with the wings exactly where they
should be.
This airplane is simple to assemble
because it has plug-on wings and stabilizers.
You just set the control throws at the
recommended low rates. These work well for
Pattern flying. Then if you feel the need to
bust loose a little bit, you can go to high rates
and let her rip!
My most recent build was a Great Planes
Pitts Special. The full-scale version is famous
around the world for its winning performance
at all levels of aerobatic competition. The
Great Planes aircraft is intended to be a really
good scale-version sport model with similar
capabilities as its full-scale counterpart.
The Pitts Special is marvelous to fly and
looks fantastic as it roars through the air. I
would not call it an easy airplane to fly. Yes,
you can do all the maneuvers in the
Aerobatics book, but you need to work at
them much more than with, say, the
ShowTime or the Ultra Stick.
The Pitts is a bit tricky to take off with and
land if there is any crosswind. It also tends to
“wind up” into a snap. This makes it hard to
time the precise moment when you want to
stop with wings level.
A good way to find out if you have an
airplane with pre-Pattern potential is to ask a
Pattern pilot. However, it is not that hard for
you to figure this out for yourself. Basically, if
the airplane makes maneuvers feel
comfortable or easy, you have what you need!
Spektrum and Futaba 2.4 GHz radios are
available now. Spektrum 2.4 GHz upgrade
modules are available for Futaba and JR
computer radios, and Futaba has just
announced its own module upgrades.
Aerobatics pilots, by the nature of their
sport, are picky about their equipment. But
they are almost magnetically attracted to any
new technology that is either “cool” or may
give them a technical advantage.
Early reports from the Pattern world
indicate that the new equipment is working
well for electric and glow models. The
reported immunity to radio interference is a
big plus for all of us. Some different receiver
antenna installation is required, but the
modern Pattern-model fuselages have plenty
of room inside.
Frequency control at a contest may be
slightly different. And I am not sure how the
rest of the world is handling this technology. I
don’t know yet how it will work if you go to a
World Championships or travel with your RC
equipment to other countries. Meanwhile, we
are all beneficiaries of a great technological
development. MA
