Radio Control Soaring-2004/12

88 MODEL AVIATION
Mike Garton, 2733 NE 95th Ave., Ankeny IA 50021; E-mail: [email protected]
RADIO CONTROL SOARING
WHAT GLIDER WOULD be good as a
first airplane? This month I’ll give my
recommendations. All of the gliders I’ll list
have excellent instructions. I will examine
trade-offs between durability and
performance.
Trainer gliders need instructions that are
complete enough to allow an
inexperienced builder to complete the
model successfully in isolation. Really
good beginner-oriented instructions
assume that you know nothing about
building or flying. The Aspire has 36
pages of photo illustrations and text.
Of course, a new pilot’s chances are
much better if he or she locates some local
fliers to help the first few times out. But
how many new people contact the local
club for help before buying a kit and
trying to build it? Did you ever wonder
how many kits are purchased by new
pilots and not finished? How many more
are test-flown without help and crashed?
What would be a good first glider? Mark (L) and Kevin Jankowski
of Ames IA retrieve a Spirit and the hi-start parachute.
One school of thought is to learn control
with a nearly indestructible EPP-foam
airplane, such as these DAW TG-3s.
The DJ Aerotech Chrysalis has received a kit upgrade; changes are detailed in the text.
The long fuselage makes it handle better than the typical trainer.
A Chrysalis Two-Meter about to release from a hi-start. It’s worth
the trouble of mail-ordering; few hobby shops stock it.
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Many new people build in isolation, fail,
and subsequently quit this sport. The
number of “isolation failures” is probably
more than 50%. This is why instructions are
especially critical in the first glider kit.
When the glider is complete, it is critical
that the new person find an experienced RC
pilot. The hobby shop, Internet searches,
and contacting AMA are possible ways to
find such a person in your proximity.
The experienced pilot can verify that the
new glider is really ready for flight. Most
crashes can be avoided with a thorough
preflight inspection. Do the surfaces move
the right direction in response to transmitter
inputs? Does the glider balance in the right
spot? The experienced pilot should test-fly
the model and assist with flight training.
A first glider does not need to be high
performance; it just needs to be strong
enough (and repairable enough) to make it
through what I call “leftsie-rightsie
training.” When an airplane flies toward the
pilot, controls are reversed compared to
visual cues. If the first glider lasts long
enough for the pilot to get past controlreversal
mistakes, it has served its purpose.
With the help of a more experienced pilot, a
new pilot is likely to progress on to
thermaling.
A high glide ratio and responsive
handling do not make the “highperformance”
gliders hard to fly. Greater
speed, lack of spiral stability, higher cost,
and more complex linkages make the
advanced gliders unsuitable for training.
Trainer gliders can have reasonable
performance. The only performance
penalties that should be built into a trainer
glider are a slightly heavier structure for
crash resistance and a forward CG for
additional stability.
My first glider was a Sig Riser. These
seemed to be in every hobby shop during
the 1980s and still are. The instructions are
excellent. The strength-to-weight ratio,
Ed Berg’s durable trainer glider will
feature an EPP-foam nose and wings with
high-performance Drela airfoils.
handling, and airfoil performance do not
compare favorably with other gliders. My
Riser served its purpose. I repaired it again
and again until I got past the left-right
mistakes. Persistence was key in my
success.
Carl Goldberg Models introduced the
Gentle Lady (GL) in the early 1980s. It
also has instructions that are detailed
enough for it to be built in isolation. The
late Carl Goldberg was a genius designer.
The GL has a well-designed structure and
great handling characteristics for a
polyhedral glider. Many people find their
first thermals with this model.
The GL’s spar is a solid rectangle of
basswood to simplify construction.
Although it is extremely light—23 ounces
ready to fly—the rubber-band-on wing
prevents serious damage in most frontal
ground impacts. However, collisions with
posts or trees are likely to warrant serious
wing repair. If you like to build and only
want to spend $50 on an initial kit, I
recommend the GL.
The DJ Aerotech Chrysalis Two-Meter
is a much more recent design. Don
Stackhouse spent a great deal of time
engineering the kit to ensure the first-time
builder’s success. Although it’s more
expensive than a GL at $85, there is much
more in the box. After buying MonoKote,
glue, and a two-channel radio, the
difference in kit prices is less significant.
The Chrysalis parts are mostly laser-cut
for accuracy. A dowel makes a simple and
durable wing LE. This model is more
durable, more fun to build, and has higher
performance than the GL. The sink rate is
similar to a GL’s, but the glide ratio and
speed range are better.
The Chrysalis has always come with the
materials needed for the builder’s choice of
a V-tail or a conventional tail. The
conventional tail has the option of a
normal-sized horizontal tail or an oversize
tail for beginners who would like extra
pitch stability.
The Two-Meter Chrysalis was designed
from the outset with the intent of offering
wing kits and fuselage plus tail kits
separately as an option. That’s why the
wing plans and instructions are totally
separate from the fuselage plus tail
instructions. This helps in repair situations
and allows people to build one wing and
two fuselages so they can have the electric
and sailplane versions available for a
minimum investment in time and money.
As of September 2004, Don Stackhouse
just completed an overhaul of the Chrysalis
kit. Changes are:
1) An optional kit for a three-piece
wing.
2) Miscellaneous clarifications and
updates in the plans and instructions.
3) Some diagonal stiffeners to give the
wing more torsional rigidity.
4) Spoilers are now shown driven by
two servos—one at each spoiler.
5) More detailed instructions for how to
(optionally) add carbon fiber to the inboard
spar caps and across the center-section joint
for winch launching.
6) New electric options, for which a
direct-drive Speed 600 and brushless
outrunner motor are shown.
The Great Planes Spirit may be the bestselling
trainer glider because of its
availability. It has online instructions for
those who want to see a well-written
manual. The Aspire and GL instructions
are even better. One downside to the Spirit
is its (higher) weight. Do not expect it to
float or thermal as well as the Chrysalis and
GL designs.
The Defiant from Northeast Sailplane
Products (NSP) was the only EPP-foam
thermal glider on the market when I wrote
this column. EPP foam is the springy kind
that flexes and bounces back without
breaking. This has an obvious advantage
for beginners who don’t have access to
buddy-box training.
Dave’s Aircraft Works (DAW) stopped
producing EPP gliders. The DAW designs
are now owned by SkyKing RC Products.
Check http://skykingrcproducts.com for
more details.
Another place to look for new, durable
trainer sailplanes that come with good
instructions is http://upslopesailplanes.com.
Ed Berg has been working on an EPP
thermal trainer. A prototype is shown in the
pictures. By the time you read this, he
should have one on the market. Ed uses
Drela airfoils for good performance.
There are several options in the ARF
category of beginner gliders. The Great
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Planes Spirit ARF, the Hangar 9 Aspire
ARF, and the Goldberg GL ARF are good
choices. The Aspire is slightly lighter than
a Spirit but otherwise similar. The GL is
much lighter than both.
These ARF sailplanes can be purchased
for less than $100, already built and
covered. The buyer typically needs to join
the wings, glue on the tail, install the
radio, and hook up the pushrods. These
tasks take approximately two evenings.
Each model comes in electric (self launch
and then the propeller folds) versions as
well.
The accompanying table shows my
opinionated ratings of the available
beginner-oriented gliders in the order that
I recommend them. Each category is rated
on a scale of one to 10.
The “Mfr Support” column indicates
how actively the manufacturer supports the
product. Does it have much beginningsoaring-
oriented information on its Web
site? Does it list a telephone number? Do
the people who designed the product
answer the phone? Are the phone-support
people expert glider fliers? Are you likely
to see the designers at major glider events?
I contacted many more manufacturers than
I listed here. Most of them had no gliders
with instructions that were complete enough
to meet my definition of a good first model.
There are many polyhedral glider designs on
the market with more-complex structures
and/or less-detailed instructions. Because of
the more difficult build, those designs would
make fine second gliders. MA
Sources:
Chrysalis:
www.djaerotech.com/
Gentle Lady:
www.carlgoldbergproducts.com/
Defiant:
www.nesail.com/
Aspire, Aspire EP:
www.horizonhobby.com/
Spirit:
www.greatplanes.com/
Riser:
www.sigmfg.com/