RADIO CONTROL JETS - 2005/03

112 MODEL AVIATION
I use Coleman Powermax as my starting
gas, and the cold temperatures affect it
greatly. The cold reduces the gas pressure—
in many cases to the point where I cannot
get enough starting gas into the turbine to
get the heat and rpm necessary to complete
the start sequence. To combat this issue, I
have resorted to keeping my starting-gas
bottle warm either by storing it under my
coat or in a heated car.
If you’re having trouble starting your
turbine in cold weather, check your groundsupport
unit to see that you are getting
enough heat and rpm during the start
sequence to advance to the fuel-pump start
sequence. Winter flying with turbines can be
fun; there is no cold
chill from the
propeller blast. Just
hit the start switch
and go fly.
Last year was
another huge
expansion period for
the turbine market. It
wasn’t because of
new manufacturers
coming into the
business as much as
growth in the variety
and the increase in
the size and power of
turbines.
We now have 7-
pound-thrust
through 35-plus-
Jim Hiller, 6090 Downs Rd., Champion OH 44481
RADIO CONTROL JETS
Shawn Cassidy’s Crusader II is a good-flying model for 12-pound-thrust turbines.
The 12-pound-thrust FunSonic turbine, distributed by Robart
Manufacturing, comes with all of the accessories shown.
AWHILE BACK I discussed the effect that
the 2006 turbine-waiver-renewal
requirements would have on us. Wouldn’t
you know it? I have to make a correction
already, but this is a good one.
After a thorough review of the rules as
passed by the Executive Committee,
existing turbine-waiver holders do not have
to perform a demonstration flight in 2005
for the 2006 renewal. Thank you to Ilona
Maine for her great effort and help in
researching and clearing up this issue. Ilona
has sent this update out to all turbine-waiver
holders with their AMA renewals.
While I am on the issue of our new
requirements, the turbine shutdown within
two seconds of fail-safe activation is a
requirement. I bring this up again to remind
all turbine pilots that the turbine shutdown
on fail-safe works only if you program your
radio’s fail-safe to shut down the turbine.
Ilona sent out information pertaining to
the best way to test this. Try simulating a
fail-safe event on the ground. Secure the
airplane, and with the turbine running, shut
off your transmitter, then count to two.
By then, the fuel pump should be shut
down, which instantly puts out the
combustion flame on a kerosene-burning
turbine. The engine will still be winding
down, but this is expected and not part of
the two-second shutdown requirement.
Be careful, and properly restrain your
model when performing this test.
Back to the fun of this hobby. It is getting
colder here in Ohio, and winter flying is the
only flying we get, short of traveling to
Florida.
pound-thrust turbines, available from
multiple sources. The new, smaller
turbines—those in the 7- to 14-pound-thrust
range—allow us to fly smaller, more
affordable models, many of which started
life as ducted-fan models.
The Wren MW-44 turbine and its SimJet
equivalent—the SimJet 700—are in
customers’ hands and flying well. They
push the old 45-size ducted-fan models
around with authority. Jet Hangar Hobbies
supplies the MW-44, which provides ideal
power for the company’s line of ducted-fan
models, now converted to turbine power.
The 11- to 14-pound-thrust turbines have
seen some incredible popularity growth.
These smaller power plants have brought
new life to many of our old 91-size ductedfan
models. They provide much more power
with a minimal weight gain. Because these
turbines are smaller than the ducted-fan
setups they replace, they allow room for the
additional fuel that a turbine requires.
Robart Manufacturing has been
distributing the FunSonic for slightly more
than a year, and it is finding a great place in
the market. This is the smallest and lightest
of the 12-pound-thrust turbines. It comes
with accessories including the electronic
control unit (ECU), battery, fuel pump, and
related items. Onboard starting is
accomplished with the now-familiar method
of an electric motor engaging the
compressor wheel nut to spin up the turbine.
As do nearly all of today’s smaller
turbines, the FunSonic has a low thrust at
idle. This is important when converting a
ducted-fan model to turbine power. Few of
these older sport aircraft have draginducing
flaps to aid in setting up for
landing, so a good low-idle thrust is as
important to the enjoyment of flying a
model as full-power thrust is.
An issue I always consider when
purchasing a turbine is service. To whom
and where do I need to send the engine if it
needs servicing? In the case of the
FunSonic which is manufactured overseas,
Robart makes it easier for us by servicing
the minor issues in its shop. If major
repairs are required, the company will ship
the engine to the original factory for
repairs.
Stepping up in size, the Wren MW-54—
available from Jet Hangar Hobbies—is
available in a 12-pound-thrust version or
the Mk.III in a 14-pound-thrust version.
You can get it as a kit or prebuilt. The kit is
a great way to go if you want to learn about
a turbine’s construction and maintenance.
A nice option is the full onboard
autostart. If you want to reduce weight, you
can omit the onboard starter motor and opt
for a removable electric starter. With this
option, the operator presses the starter
motor up against the compressor wheel nut
the same way you would use a starter
motor on a piston engine, although in this
case it is a smaller and higher-rpm starter
motor.
The SimJet 1200 has been around for
quite awhile, and it has proven to be
popular. This is a 12- or 14-pound-thrust
turbine distributed by Great Northern
Models in the North American market. It
also comes with an onboard autostart. I
have flown it a couple times, and it is a
nice-handling package.
One option from SimJet is an IR
ground-support terminal. You don’t plug
the ground-support unit into your model;
you stand next to your airplane, point it at
the model, and read your running turbine’s
performance numbers.
Service to the SimJet turbines is done on
a limited—though developing—basis by
Great Northern Models in Canada. The
company does ship major repairs to the
overseas factory when required.
The 12-pound-thrust PST turbine has
also been around for a while. It features
onboard autostart. Distributed by HeliJet
International, PST turbines utilize a similar
policy for repairs.
The Artes Bee and Super Bee turbines
are manufactured in Mexico City and
distributed by Artes Jet USA of Los
Angeles, California. As with the other
turbines, onboard autostart is standard,
although my Artes came with an optional
air-start line plumbed in. I have flown many
models with this engine, and it has proven
to be a reliable setup.
The Artes turbines come with a fully
automated digital electronic control
(FADEC) ECU. It is a good controller with
many operator features and is a lightweight
design. I have flown this unit in many
installations, and it is a quiet ECU in terms
of radio-interference noise. I have not had a
single shutdown from my programmed failsafe,
and this includes twin-turbine
installations.
That is particularly good performance
when you consider that the shutdown
sequence does not have a noticeable delay;
it is almost immediate with the fail-safe
shutdown. Not all of my turbines have been
this trouble-free when it comes to noise
generated by the ECU and fuel pump.
Paul Pigneri of Artes Jet USA arranges
service for Artes turbines. For major repairs,
he will overnight you a completed UPS
shipper with the proper information for
international shipments filled out. You
114 MODEL AVIATION
package your engine and call UPS, which
will deliver it to the Mexico City factory for
repairs. I used this service to update my
turbine and was satisfied with the ease of it.
The Artes name has meaning to many of
us who have been flying turbines for the
past 10 years. Jesus Artes was part of the
team including Kurt Schreckling that
brought the KJ-66 to production as a kit and
supplied the components for many of the
turbine manufacturers. The KJ-66 is the
basis for most of the class of 17-poundthrust
turbines that developed up to the 28-
pound-thrust turbines we fly today.
I have been fortunate enough to have
flown almost all of the turbines I have
mentioned, and I have been impressed.
These smaller power plants are some of the
nicest handling of all the turbines. All of
them are among the fastest-accelerating
turbines from idle to full throttle. Most are
as fast as the AMT Mercury, which is the
benchmark for throttle-up time.
The fuel usage allows you to fly all of
the 12- to 14-pound-thrust turbines with 50-
64 ounces of onboard fuel and have good
five- to seven-minute flight times. These
smaller, lighter airframes and landing-gear
systems cost significantly less than those of
the larger turbine models. This has
motivated a growing group of modelers to
try turbine power. MA
Sources:
Artes Bee and Super Bee:
Artes Jet USA
www.artesjetusa.com
FunSonic:
Robart Manufacturing
www.robart.com
PST turbine:
HeliJet R/C International
www.helijet.ca
SimJet 1200 and 1200PLUS:
Great Northern Models
www.greatnorthernmodels.com
Wren MW-44 and Wren MW-54:
Jet Hangar Hobbies
www.jethangar.com