RADIO CONTROL JETS - 2004/08

August 2004 129
THEY’RE FINISHED, they’ve been approved, and by the time
you read this, we will have been living with them for some time. I’m
referring to our latest turbine rules. Let’s discuss them so none of us
is caught off guard.
Where do you get a copy? That’s easy; go to the AMA Web site
and work your way through to the documents section. You are
looking for document 513: “Safety Regulations for Fixed/Rotary
Wing Model Aircraft Gas Turbines.” While you’re there, download
documents 538 and 576: “Turbine Applicant Flight Demonstration”
and “Pilot Turbine Waiver Renewal Affidavit.”
Highlights: Now we can power our models using turbines with up
to 45 pounds of thrust, but twin turbines are restricted to a maximum
of 50 pounds of thrust.
The perspective has changed on twin-turbine power limits. The
new maximum limit is based on restricting the power of the model
when both turbines are running. The previous 70-pound-thrust limit
was based on providing a reasonable power-to-weight ratio after a
flameout of one of the turbines. If your turbine engine goes out on
that twin, you now have to do a little more “pilot stuff” to bring the
aircraft home safely. There is less power and less reserve for when
things go wrong.
The next matter is the controversial 200 mph speed limit.
Experienced jet modelers have their own opinions based on their
flying styles, newcomers tend to look forward to all the speed of a
jet, and the uninitiated have opinions varying to both extremes. One
thing all agree on is that a 200 mph flight is fast.
The rule states that we are not to exceed 200 mph velocity.
Notice that the power-to-weight-ratio limit has been eliminated.
Experience proved that it really wasn’t the greatest limiter to speed;
airframe drag was more important. We can now enjoy the benefits
of awesome power-to-weight ratios, but it is up to us to use our skill
and discretion to obey this speed limit.
Heck, even with 45 pounds of thrust, you probably still can’t get
one of those Eurosports to go 200 mph, but it sure will be fun to
have all that power to accelerate out of slow, high-alpha flight. Use
it wisely.
Another change is the wording around “brakes or no brakes.” It
now reads, “The model shall be able to come to a controlled stop on
command with the engine at idle on a level hard surface.”
I believe in brakes. In the early days, I flew 20 turbine flights
without brakes to demonstrate that I could, including 10 flights at
our AMA National Flying Site, and I can tell you that brakes sure
make flying much easier. I did not overrun any runway during those
20 flights; all landings came to a complete stop on the runway. I did
this with soft tires and a slight drag setup on the nose-gear tire. It
worked, but I never want to go back to that setup. Brakes are great.
Item eight continues to eliminate loose plasma tanks. It also
covers fuel shutoff requirements. Two methods are to be in place:
one by manual means and the other by remote control. As in the
past, we must keep two methods of shutting down the turbine in
place.
Item nine’s requirement is a good practice. It states that all
turbine models must be equipped with a radio and/or an enginecontrol
unit (ECU) that will bring the turbine to idle or preferably
shut off the turbine within two seconds of fail-safe activation.
We have until January 1, 2005, to comply. Anyone with a
modern pulse code modulation (PCM) radio equipped with a failsafe
function should program the fail-safe to shut off the turbine.
The two-year phase-in is to allow ECU manufacturers time to
modify their systems to comply with this rule, although many of our
Jim Hiller, 6090 Downs Rd., Champion OH 44481
RADIO CONTROL JETS
People from AirPac Models brought the new turbine-powered
Skymaster Gripen ARF to Florida Jets 2004.
Sung Su Kim brought his new Yellow Aircraft F-15 to Florida
Jets. The 27-pound model is powered by two Artes Bees.
Only Francis Prischner and Vern and Larry Kramer could turn
this AMT 400-powered KingCat ARF into a masterpiece.
08sig5.QXD 5/21/04 11:20 am Page 129
current ECUs already have this feature.
The chance of a postcrash fire is
greatly reduced if the fire in the turbine is
extinguished prior to a crash so it won’t
be the source of ignition. Program your
fail-safe to shut down the turbine; it
makes a difference.
Flightline requirements now include a
special emphasis on the need to have a
fire extinguisher and water-based firesuppression
equipment available on the
flightline, and to have preparations for
emergency response in place. This is good
practice for any modeling activity—not
only turbines.
As for the pilot requirements, let’s
start with existing turbine-waiver holders.
We now have to submit AMA document
576 every year, starting with our 2006
AMA renewal, and it is to be notarized.
The document requires your signature and
that of another experienced turbinewaiver
holder.
Document 576 is the “Pilot Turbine
Waiver Renewal Affidavit.” We are
required to affirm that we are maintaining
our skills as turbine modelers by verifying
that we have made at least 20 flights on
turbine-powered model aircraft in the
preceding 24 months. You must maintain
a pilot log as proof that you are an
“experienced turbine pilot.”
I have maintained a log on each
turbine model, so now I am switching to a
pilot log to comply with this rule. I keep
my log on my PDA in a spreadsheet form,
but a hand-written log is more than
adequate.
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This document is not required with our
2005 renewal. This is to allow everyone
ample opportunity to make 20 flights during
the two-year period between initiation and
implementation of the rule.
The new process for attaining your
turbine waiver (section 22) is based on
much discussion and effort to make it more
realistic. Last year’s temporary procedure
that allowed the use of a training cord and
an experienced turbine-waiver pilot on the
other transmitter on a turbine-powered
model proved to be successful, and the rules
reflect this experience.
Let’s consider “prior experience.”
Document 513 specifies “50 flights on a
high-performance model capable of
sustained speeds of 100 mph or higher.”
This lowers the speed from 150 mph and is
a more realistic view of the actual speeds of
which our high-performance models are
capable.
This same model may be used for your
turbine-waiver qualification flight, but you
can use your turbine-powered model for
your qualification flight based on the
second alternative.
An experienced turbine-waiver holder
can assist an applicant pilot with the use of
the buddy-box system. The turbine model
can be flown with the slaved transmitter in
the hands of the applicant and the master
transmitter under the control of the
experienced turbine-waiver holder.
The experienced waiver holder can assist
the new applicant in this manner until—in
his or her judgment—the applicant is ready
to perform his or her qualification flight.
The applicant will then perform the turbine
qualification flight according to AMA
document 538: “Turbine Applicant Flight
Demonstration.”
This flight consists of two parts. The
first part covers a verbal understanding of
the AMA turbine rules and some general
discussion about the differences in the
operation of a turbine engine. It involves
verbal discussion and actions during the
starting and shut-down procedures.
The second part is the flight itself: a
demonstration of the applicant’s flight
skills. The applicant is expected to prove his
or her skills, with particular attention to
control during takeoff and landing. The
model must remain within 10 feet of either
side of the runway centerline during the
takeoff roll.
A go-around is to be performed as a
demonstration of how to deal with the
slower throttle response of a turbine. This is
to be in the opposite direction of the
landing, provided field conditions allow it.
If the sky is crowded with other aircraft,
a strong wind is blowing, or there is any
other situation that may not allow this
maneuver to be performed in the reverse
direction, it is acceptable and prudent to
perform the maneuver in the same direction
as the upcoming landing.
Another unusual maneuver—a
Horizontal Eight—is based on the same
maneuver performed in Scale competition.
(Please read the Scale competition rules to
understand the maneuver.) This is intended
to allow the applicant to prove his or her
control of the model in a left-hand and a
right-hand traffic pattern; the Horizontal
Eight maneuver has elements of both.
The applicant must demonstrate two
aerobatic maneuvers; both must have
looping and rolling elements. A simple
Cuban Eight, Humpty Bump, Split “S,” or
even a loop with a roll immediately
following will suffice. The applicant will be
judged on control rather than precision.
I hope this helps existing turbine-waiver
holders and future turbine modelers to
understand our new rules. Let’s go out and
make them work for us. We have roughly
800 turbine-waiver holders, and based on
turbine sales, more have yet to attain their
waivers. Those of us with waivers can
help the new pilots get into turbine
flying—using their own models—so they
too can obtain their waivers.
I thank the leadership of AMA and of
our Special Interest Group, the Jet Pilot’s
Organization (JPO), for stepping forward
and participating in this cycle of rules
revisions. The leadership of JPO provided
input from the jet-modeling community
during the development and presentation
of the proposed rules changes to the AMA
Safety Committee and Executive Council.
Check out the JPO Web site at
www.jetpilots.org to find out who we are
and how you can join. MA
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