140 MODEL AVIATION
SUMMER IS BACK and jet flying is in
full force here in the Midwest. I got a new
turbine this winter—an ArtesJet Eagle—
and with the good flying weather, I have
been flying it hard. My turbines get used.
The ArtesJet Eagle is one of the newest
turbines on the market, and it is an
international effort. The turbine design is
from Spain, it is manufactured in Mexico
City, Mexico, and it is tuned and
accessorized in California. Check out
www.artesjet.com for complete
information.
The Eagle is available in two versions:
a stock 27-pound-thrust turbine and a
Super Eagle that is rated at 30 pounds of
thrust. Both engines are the same basic
size and contain the same compressor as
similarly rated turbines. They perform
similarly in terms of throttle response and
idle thrust. My Eagle is rated at 27 pounds
of thrust, and at 600 feet above sea level, it
produces slightly more than 27 pounds of
thrust on the test stand.
The ArtesJet turbine comes equipped
with a small, lightweight controller called
the Intelligent Control System (I.C.S.).
The I.C.S. is similar to an intelligent speed
controller that converts the throttle signal
to control the fuel pump within preset
limits and monitors the turbine for any
parameters operating outside preset limits.
In addition, it is a computer system that
controls the start-up and shut-down
processes. A Hand Data Terminal, or
HDT, is supplied to monitor the engine’s
performance and to program the turbine to
match your radio.
The start-up and shut-down processes
are similar to those of most turbines on the
market today. The starting process is
initiated by cycling the throttle stick to full
throttle and back to idle. A small onboard
starting gas tank is used to light off on a
glow plug. The fuel pump then pumps the
kerosene into the turbine to accelerate it to
idle rpm. When the turbine has stabilized
at idle, the I.C.S. returns control of the
throttle to the radio system.
Unlike a JetCat’s starting process, the
ArtesJet turbine does not run up to 50,000
rpm and then throttle back to idle. You
have to listen carefully or watch the HDT
to determine when the turbine is at idle
and you have throttle control.
Shut-down of the ArtesJet turbines is
immediate with reduction of the idle trim.
A cooling period using the onboard starter
motor takes place. The nice thing about
this controller is that you can turn off the
transmitter at this time, and the I.C.S. will
continue cooling the turbine. (You did
program your fail-safe, didn’t you?)
I like the supplied shutoff valves for the
turbine starting gas and the kerosene. They
are the robust and reliable brass units that
have become so popular. The connection
to the I.C.S. uses servo-type connectors, so
regular servo extensions can be used if
required. The fuel pump is a nice-looking
unit, and so far it has been trouble free.
The ArtesJet turbines only use 2.5% oil
mixture in the fuel—roughly half of what
my other turbines use. I have to keep my
fuels separate so I don’t mix them up, but I
shouldn’t complain. The most expensive
part of my fuel bill is the cost of turbine
Jim Hiller, 6090 Downs Rd., Champion OH 44481
RADIO CONTROL JETS
Welcome William Jackson into the turbine crowd. This is his Bandit powered by a RAM
750. Carlos Villarreal provided ground school training.
Twin AMT turbines power Roger Shipley’s huge A-10. Paint will be added with the next
weight reduction. This model weighs less than the 55-pound limit.
10sig5.QXD 7/23/04 9:27 am Page 140
October 2004 141
oil, so I just cut my fuel bill in half. Good
deal!
Overall, I am quite happy with this new
turbine, and I have been flying it hard and
heavy. I have not had a flameout to date. It
runs like a turbine should, starts reliably,
throttles well, and stays within its operating
parameters so the I.C.S. does not shut it
down.
I’ve observed that there is a variety of
suppliers building quality turbines. Last
weekend I looked at our small group of sport
turbine modelers and it really hit home. The
ArtesJet, a JetCat, a PST, and a SimJet
turbine were performing flawlessly. The
turbines have come of age, and these
companies are not the only quality turbine
manufacturers out there. There is a great
selection available.
I heard a comment the other day about a jet
model I was flying. It did not have flaps, and
a gentleman questioned whether it was okay
to fly a turbine model without them. The
ensuing conversation showed a
misunderstanding about flaps.
AMA does not require flaps on a turbine
model because they are really unnecessary.
So why do we have them? Because they
make landing your model easier. Flaps do
two basic things for us. They allow the wing
to create greater lift and therefore lower the
landing speed, and they increase the drag,
allowing steeper landing approaches.
The first few degrees of flap travel—up
to approximately 10°—add significant lift
and not too much drag. This is useful when
you want additional lift, such as during
takeoff. I use this partial flap travel when
things go wrong, such as in a dead-stick
landing and I’m a little slow coming around
the corner. That extra lift can go a long way
toward safely turning final instead of
snapping out of the turn and into the ground.
The remaining flap travel greatly
increases the drag and continues to increase
lift. It’s the extra drag that helps when
landing. The additional drag can be used to
improve your spot-landing precision. Often,
the additional drag from extended landing
gear combined with flaps allows the pilot to
carry some throttle on final approach. This
provides the pilot the opportunity to use the
WWW.PSPEC.COM
Complete engine and muffler packages are available.
VISIT US AT WWW.PSPEC.COM.
DEALER INQUIRIES WELCOME!
TWISTER 4-STROKE MUFFLERS & ELBOWS
PISTON/CYLINDER ASSEMBLIES
ULTRATHRUST MUFFLERS
PERFORMANCE SPECIALTIES
PO Box 3146 • Gardnerville, NV 89410
Phone: 775-265-7523 • Fax: 775-265-7522
10sig5.QXD 7/23/04 9:28 am Page 141
142 MODEL AVIATION
throttle to control the angle of approach and
consequently select his or her touchdown
point more accurately.
Many of our jet models have clean
designs, so the idle thrust of the turbine
makes for a flat approach. The additional
drag through the use of flaps is a great aide in
landing.
But not all things have only a good side;
flaps have their quirks. The first problem is
one of pitch-trim changes. The flaps create
lift behind the CG, pushing the nose down,
but they also pull the air down behind them.
This causes the air to strike the top side of the
stabilizer, which tends to push the tail of the
aircraft down. Conflicting pitch-trim
effects—it is the balance between these two
that affect the pitch-trim change on any
particular airframe.
When flaps are extended at hard angles, it
creates turbulence. This can have some
strange effects on our airplanes. My
experience with twin vertical-fin aircraft and
flaps has been interesting.
The F-15 Eagle—particularly with
loaded-up hardpoints—can start some
unwanted wing waggling. The same model
with the hardpoints loaded up but without the
flaps extended lands straight and smooth.
On a swept-wing aircraft such as the old
Starfire, the F-86, the F-100, or the MiG-15, -
17, or -19, flaps actually help stabilize the
model during the landing approach. These
aircraft tend to be easier to set up for landing
when you extend the flaps. Since these are
clean aircraft, the additional drag of flaps
really comes into play by allowing the pilot to
carry some throttle on approach, aiding in
precision pointing to the touchdown spot.
Not all aircraft wings are the same. Deltawing
aircraft such as the F-16 Falcon or the
venerable old A-4 Skyhawk have low aspect
ratios, and flaps don’t really have much
effect. The F-16 actually uses flaperons, and
they are located near the stabilizer.
At travels up to approximately 15° they
work well, but beyond that I don’t like them;
they affect the pitch response. Low-aspectratio
wings such as these allow the pilot to
use angle of attack to adequately and easily
control the rate of descent. The drag of a lowaspect-
ratio wing increases rapidly with angle
6x3 . . . . $
6.5x4 . . . .
7x4 . . . . . .
7.5x5 . . . .
8x4 . . . . . .
8x5 . . . . . .
8.5x5 . . . .
9x6 . . . . . .
10x7 . . . . .
10x8 . . . . .
11x7 . . . . .
12x8 . . . . .
13x8.5 . . .
1.50
1.50
1.50
1.50
2.25
2.25
2.25
2.45
2.95
2.95
3.25
3.45
3.95
•Ultra lightweight
•Thin, flexible design
•Undercambered blades
•Superior performance
•Made of glass-filled nylon
Windsor Propeller Co. Inc.
www.masterairscrew.com
voice 916-631-8385
ELECTRIC ONLY SERIES
SIZES MASTER AIRSCREW
of attack. By flying the approach at reduced
speeds, you can create enough drag to allow
carrying some power on final.
I have begun to take the next step and use
a crow setup to aide in flying out of a local
field with trees on the approach end of the
runway. A steeper-than-normal approach is
required. Crow is a setup in which the flaps
are lowered as normal, but you also raise the
ailerons, thereby creating more drag. This
technique has been used successfully by the
sailplane fraternity.
It works by effectively increasing the drag
so I get a much steeper approach. My model
does not require any pitch-trim correction
when flying with regular flaps, but when I add
the aileron-up of crow, I get a huge upelevator
pitch effect.
I have a program mix of 18% downelevator
with crow application. There is a
good, straight-pitch transition with flap/crow
application, and a nice, steep approach,
allowing me to fly from this—by jet
standards—tight field.
I hope some of this can help you with your
model flying. I look forward to seeing you at
the next jet meet. MA
Did You Know …
That any donation you make to
AMA is tax-deductible?
AMA is a 501(c)(3), not-forprofit
association. This means
that any funds you donate beyond
your regular membership dues
can be deducted from your taxes.
Please consider donating to
AMA. Your gift will help us
continue our efforts to improve
your organization.
10sig5.QXD 7/23/04 9:28 am Page 142
Edition: Model Aviation - 2004/10
Page Numbers: 140,141,142
Edition: Model Aviation - 2004/10
Page Numbers: 140,141,142
140 MODEL AVIATION
SUMMER IS BACK and jet flying is in
full force here in the Midwest. I got a new
turbine this winter—an ArtesJet Eagle—
and with the good flying weather, I have
been flying it hard. My turbines get used.
The ArtesJet Eagle is one of the newest
turbines on the market, and it is an
international effort. The turbine design is
from Spain, it is manufactured in Mexico
City, Mexico, and it is tuned and
accessorized in California. Check out
www.artesjet.com for complete
information.
The Eagle is available in two versions:
a stock 27-pound-thrust turbine and a
Super Eagle that is rated at 30 pounds of
thrust. Both engines are the same basic
size and contain the same compressor as
similarly rated turbines. They perform
similarly in terms of throttle response and
idle thrust. My Eagle is rated at 27 pounds
of thrust, and at 600 feet above sea level, it
produces slightly more than 27 pounds of
thrust on the test stand.
The ArtesJet turbine comes equipped
with a small, lightweight controller called
the Intelligent Control System (I.C.S.).
The I.C.S. is similar to an intelligent speed
controller that converts the throttle signal
to control the fuel pump within preset
limits and monitors the turbine for any
parameters operating outside preset limits.
In addition, it is a computer system that
controls the start-up and shut-down
processes. A Hand Data Terminal, or
HDT, is supplied to monitor the engine’s
performance and to program the turbine to
match your radio.
The start-up and shut-down processes
are similar to those of most turbines on the
market today. The starting process is
initiated by cycling the throttle stick to full
throttle and back to idle. A small onboard
starting gas tank is used to light off on a
glow plug. The fuel pump then pumps the
kerosene into the turbine to accelerate it to
idle rpm. When the turbine has stabilized
at idle, the I.C.S. returns control of the
throttle to the radio system.
Unlike a JetCat’s starting process, the
ArtesJet turbine does not run up to 50,000
rpm and then throttle back to idle. You
have to listen carefully or watch the HDT
to determine when the turbine is at idle
and you have throttle control.
Shut-down of the ArtesJet turbines is
immediate with reduction of the idle trim.
A cooling period using the onboard starter
motor takes place. The nice thing about
this controller is that you can turn off the
transmitter at this time, and the I.C.S. will
continue cooling the turbine. (You did
program your fail-safe, didn’t you?)
I like the supplied shutoff valves for the
turbine starting gas and the kerosene. They
are the robust and reliable brass units that
have become so popular. The connection
to the I.C.S. uses servo-type connectors, so
regular servo extensions can be used if
required. The fuel pump is a nice-looking
unit, and so far it has been trouble free.
The ArtesJet turbines only use 2.5% oil
mixture in the fuel—roughly half of what
my other turbines use. I have to keep my
fuels separate so I don’t mix them up, but I
shouldn’t complain. The most expensive
part of my fuel bill is the cost of turbine
Jim Hiller, 6090 Downs Rd., Champion OH 44481
RADIO CONTROL JETS
Welcome William Jackson into the turbine crowd. This is his Bandit powered by a RAM
750. Carlos Villarreal provided ground school training.
Twin AMT turbines power Roger Shipley’s huge A-10. Paint will be added with the next
weight reduction. This model weighs less than the 55-pound limit.
10sig5.QXD 7/23/04 9:27 am Page 140
October 2004 141
oil, so I just cut my fuel bill in half. Good
deal!
Overall, I am quite happy with this new
turbine, and I have been flying it hard and
heavy. I have not had a flameout to date. It
runs like a turbine should, starts reliably,
throttles well, and stays within its operating
parameters so the I.C.S. does not shut it
down.
I’ve observed that there is a variety of
suppliers building quality turbines. Last
weekend I looked at our small group of sport
turbine modelers and it really hit home. The
ArtesJet, a JetCat, a PST, and a SimJet
turbine were performing flawlessly. The
turbines have come of age, and these
companies are not the only quality turbine
manufacturers out there. There is a great
selection available.
I heard a comment the other day about a jet
model I was flying. It did not have flaps, and
a gentleman questioned whether it was okay
to fly a turbine model without them. The
ensuing conversation showed a
misunderstanding about flaps.
AMA does not require flaps on a turbine
model because they are really unnecessary.
So why do we have them? Because they
make landing your model easier. Flaps do
two basic things for us. They allow the wing
to create greater lift and therefore lower the
landing speed, and they increase the drag,
allowing steeper landing approaches.
The first few degrees of flap travel—up
to approximately 10°—add significant lift
and not too much drag. This is useful when
you want additional lift, such as during
takeoff. I use this partial flap travel when
things go wrong, such as in a dead-stick
landing and I’m a little slow coming around
the corner. That extra lift can go a long way
toward safely turning final instead of
snapping out of the turn and into the ground.
The remaining flap travel greatly
increases the drag and continues to increase
lift. It’s the extra drag that helps when
landing. The additional drag can be used to
improve your spot-landing precision. Often,
the additional drag from extended landing
gear combined with flaps allows the pilot to
carry some throttle on final approach. This
provides the pilot the opportunity to use the
WWW.PSPEC.COM
Complete engine and muffler packages are available.
VISIT US AT WWW.PSPEC.COM.
DEALER INQUIRIES WELCOME!
TWISTER 4-STROKE MUFFLERS & ELBOWS
PISTON/CYLINDER ASSEMBLIES
ULTRATHRUST MUFFLERS
PERFORMANCE SPECIALTIES
PO Box 3146 • Gardnerville, NV 89410
Phone: 775-265-7523 • Fax: 775-265-7522
10sig5.QXD 7/23/04 9:28 am Page 141
142 MODEL AVIATION
throttle to control the angle of approach and
consequently select his or her touchdown
point more accurately.
Many of our jet models have clean
designs, so the idle thrust of the turbine
makes for a flat approach. The additional
drag through the use of flaps is a great aide in
landing.
But not all things have only a good side;
flaps have their quirks. The first problem is
one of pitch-trim changes. The flaps create
lift behind the CG, pushing the nose down,
but they also pull the air down behind them.
This causes the air to strike the top side of the
stabilizer, which tends to push the tail of the
aircraft down. Conflicting pitch-trim
effects—it is the balance between these two
that affect the pitch-trim change on any
particular airframe.
When flaps are extended at hard angles, it
creates turbulence. This can have some
strange effects on our airplanes. My
experience with twin vertical-fin aircraft and
flaps has been interesting.
The F-15 Eagle—particularly with
loaded-up hardpoints—can start some
unwanted wing waggling. The same model
with the hardpoints loaded up but without the
flaps extended lands straight and smooth.
On a swept-wing aircraft such as the old
Starfire, the F-86, the F-100, or the MiG-15, -
17, or -19, flaps actually help stabilize the
model during the landing approach. These
aircraft tend to be easier to set up for landing
when you extend the flaps. Since these are
clean aircraft, the additional drag of flaps
really comes into play by allowing the pilot to
carry some throttle on approach, aiding in
precision pointing to the touchdown spot.
Not all aircraft wings are the same. Deltawing
aircraft such as the F-16 Falcon or the
venerable old A-4 Skyhawk have low aspect
ratios, and flaps don’t really have much
effect. The F-16 actually uses flaperons, and
they are located near the stabilizer.
At travels up to approximately 15° they
work well, but beyond that I don’t like them;
they affect the pitch response. Low-aspectratio
wings such as these allow the pilot to
use angle of attack to adequately and easily
control the rate of descent. The drag of a lowaspect-
ratio wing increases rapidly with angle
6x3 . . . . $
6.5x4 . . . .
7x4 . . . . . .
7.5x5 . . . .
8x4 . . . . . .
8x5 . . . . . .
8.5x5 . . . .
9x6 . . . . . .
10x7 . . . . .
10x8 . . . . .
11x7 . . . . .
12x8 . . . . .
13x8.5 . . .
1.50
1.50
1.50
1.50
2.25
2.25
2.25
2.45
2.95
2.95
3.25
3.45
3.95
•Ultra lightweight
•Thin, flexible design
•Undercambered blades
•Superior performance
•Made of glass-filled nylon
Windsor Propeller Co. Inc.
www.masterairscrew.com
voice 916-631-8385
ELECTRIC ONLY SERIES
SIZES MASTER AIRSCREW
of attack. By flying the approach at reduced
speeds, you can create enough drag to allow
carrying some power on final.
I have begun to take the next step and use
a crow setup to aide in flying out of a local
field with trees on the approach end of the
runway. A steeper-than-normal approach is
required. Crow is a setup in which the flaps
are lowered as normal, but you also raise the
ailerons, thereby creating more drag. This
technique has been used successfully by the
sailplane fraternity.
It works by effectively increasing the drag
so I get a much steeper approach. My model
does not require any pitch-trim correction
when flying with regular flaps, but when I add
the aileron-up of crow, I get a huge upelevator
pitch effect.
I have a program mix of 18% downelevator
with crow application. There is a
good, straight-pitch transition with flap/crow
application, and a nice, steep approach,
allowing me to fly from this—by jet
standards—tight field.
I hope some of this can help you with your
model flying. I look forward to seeing you at
the next jet meet. MA
Did You Know …
That any donation you make to
AMA is tax-deductible?
AMA is a 501(c)(3), not-forprofit
association. This means
that any funds you donate beyond
your regular membership dues
can be deducted from your taxes.
Please consider donating to
AMA. Your gift will help us
continue our efforts to improve
your organization.
10sig5.QXD 7/23/04 9:28 am Page 142
Edition: Model Aviation - 2004/10
Page Numbers: 140,141,142
140 MODEL AVIATION
SUMMER IS BACK and jet flying is in
full force here in the Midwest. I got a new
turbine this winter—an ArtesJet Eagle—
and with the good flying weather, I have
been flying it hard. My turbines get used.
The ArtesJet Eagle is one of the newest
turbines on the market, and it is an
international effort. The turbine design is
from Spain, it is manufactured in Mexico
City, Mexico, and it is tuned and
accessorized in California. Check out
www.artesjet.com for complete
information.
The Eagle is available in two versions:
a stock 27-pound-thrust turbine and a
Super Eagle that is rated at 30 pounds of
thrust. Both engines are the same basic
size and contain the same compressor as
similarly rated turbines. They perform
similarly in terms of throttle response and
idle thrust. My Eagle is rated at 27 pounds
of thrust, and at 600 feet above sea level, it
produces slightly more than 27 pounds of
thrust on the test stand.
The ArtesJet turbine comes equipped
with a small, lightweight controller called
the Intelligent Control System (I.C.S.).
The I.C.S. is similar to an intelligent speed
controller that converts the throttle signal
to control the fuel pump within preset
limits and monitors the turbine for any
parameters operating outside preset limits.
In addition, it is a computer system that
controls the start-up and shut-down
processes. A Hand Data Terminal, or
HDT, is supplied to monitor the engine’s
performance and to program the turbine to
match your radio.
The start-up and shut-down processes
are similar to those of most turbines on the
market today. The starting process is
initiated by cycling the throttle stick to full
throttle and back to idle. A small onboard
starting gas tank is used to light off on a
glow plug. The fuel pump then pumps the
kerosene into the turbine to accelerate it to
idle rpm. When the turbine has stabilized
at idle, the I.C.S. returns control of the
throttle to the radio system.
Unlike a JetCat’s starting process, the
ArtesJet turbine does not run up to 50,000
rpm and then throttle back to idle. You
have to listen carefully or watch the HDT
to determine when the turbine is at idle
and you have throttle control.
Shut-down of the ArtesJet turbines is
immediate with reduction of the idle trim.
A cooling period using the onboard starter
motor takes place. The nice thing about
this controller is that you can turn off the
transmitter at this time, and the I.C.S. will
continue cooling the turbine. (You did
program your fail-safe, didn’t you?)
I like the supplied shutoff valves for the
turbine starting gas and the kerosene. They
are the robust and reliable brass units that
have become so popular. The connection
to the I.C.S. uses servo-type connectors, so
regular servo extensions can be used if
required. The fuel pump is a nice-looking
unit, and so far it has been trouble free.
The ArtesJet turbines only use 2.5% oil
mixture in the fuel—roughly half of what
my other turbines use. I have to keep my
fuels separate so I don’t mix them up, but I
shouldn’t complain. The most expensive
part of my fuel bill is the cost of turbine
Jim Hiller, 6090 Downs Rd., Champion OH 44481
RADIO CONTROL JETS
Welcome William Jackson into the turbine crowd. This is his Bandit powered by a RAM
750. Carlos Villarreal provided ground school training.
Twin AMT turbines power Roger Shipley’s huge A-10. Paint will be added with the next
weight reduction. This model weighs less than the 55-pound limit.
10sig5.QXD 7/23/04 9:27 am Page 140
October 2004 141
oil, so I just cut my fuel bill in half. Good
deal!
Overall, I am quite happy with this new
turbine, and I have been flying it hard and
heavy. I have not had a flameout to date. It
runs like a turbine should, starts reliably,
throttles well, and stays within its operating
parameters so the I.C.S. does not shut it
down.
I’ve observed that there is a variety of
suppliers building quality turbines. Last
weekend I looked at our small group of sport
turbine modelers and it really hit home. The
ArtesJet, a JetCat, a PST, and a SimJet
turbine were performing flawlessly. The
turbines have come of age, and these
companies are not the only quality turbine
manufacturers out there. There is a great
selection available.
I heard a comment the other day about a jet
model I was flying. It did not have flaps, and
a gentleman questioned whether it was okay
to fly a turbine model without them. The
ensuing conversation showed a
misunderstanding about flaps.
AMA does not require flaps on a turbine
model because they are really unnecessary.
So why do we have them? Because they
make landing your model easier. Flaps do
two basic things for us. They allow the wing
to create greater lift and therefore lower the
landing speed, and they increase the drag,
allowing steeper landing approaches.
The first few degrees of flap travel—up
to approximately 10°—add significant lift
and not too much drag. This is useful when
you want additional lift, such as during
takeoff. I use this partial flap travel when
things go wrong, such as in a dead-stick
landing and I’m a little slow coming around
the corner. That extra lift can go a long way
toward safely turning final instead of
snapping out of the turn and into the ground.
The remaining flap travel greatly
increases the drag and continues to increase
lift. It’s the extra drag that helps when
landing. The additional drag can be used to
improve your spot-landing precision. Often,
the additional drag from extended landing
gear combined with flaps allows the pilot to
carry some throttle on final approach. This
provides the pilot the opportunity to use the
WWW.PSPEC.COM
Complete engine and muffler packages are available.
VISIT US AT WWW.PSPEC.COM.
DEALER INQUIRIES WELCOME!
TWISTER 4-STROKE MUFFLERS & ELBOWS
PISTON/CYLINDER ASSEMBLIES
ULTRATHRUST MUFFLERS
PERFORMANCE SPECIALTIES
PO Box 3146 • Gardnerville, NV 89410
Phone: 775-265-7523 • Fax: 775-265-7522
10sig5.QXD 7/23/04 9:28 am Page 141
142 MODEL AVIATION
throttle to control the angle of approach and
consequently select his or her touchdown
point more accurately.
Many of our jet models have clean
designs, so the idle thrust of the turbine
makes for a flat approach. The additional
drag through the use of flaps is a great aide in
landing.
But not all things have only a good side;
flaps have their quirks. The first problem is
one of pitch-trim changes. The flaps create
lift behind the CG, pushing the nose down,
but they also pull the air down behind them.
This causes the air to strike the top side of the
stabilizer, which tends to push the tail of the
aircraft down. Conflicting pitch-trim
effects—it is the balance between these two
that affect the pitch-trim change on any
particular airframe.
When flaps are extended at hard angles, it
creates turbulence. This can have some
strange effects on our airplanes. My
experience with twin vertical-fin aircraft and
flaps has been interesting.
The F-15 Eagle—particularly with
loaded-up hardpoints—can start some
unwanted wing waggling. The same model
with the hardpoints loaded up but without the
flaps extended lands straight and smooth.
On a swept-wing aircraft such as the old
Starfire, the F-86, the F-100, or the MiG-15, -
17, or -19, flaps actually help stabilize the
model during the landing approach. These
aircraft tend to be easier to set up for landing
when you extend the flaps. Since these are
clean aircraft, the additional drag of flaps
really comes into play by allowing the pilot to
carry some throttle on approach, aiding in
precision pointing to the touchdown spot.
Not all aircraft wings are the same. Deltawing
aircraft such as the F-16 Falcon or the
venerable old A-4 Skyhawk have low aspect
ratios, and flaps don’t really have much
effect. The F-16 actually uses flaperons, and
they are located near the stabilizer.
At travels up to approximately 15° they
work well, but beyond that I don’t like them;
they affect the pitch response. Low-aspectratio
wings such as these allow the pilot to
use angle of attack to adequately and easily
control the rate of descent. The drag of a lowaspect-
ratio wing increases rapidly with angle
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of attack. By flying the approach at reduced
speeds, you can create enough drag to allow
carrying some power on final.
I have begun to take the next step and use
a crow setup to aide in flying out of a local
field with trees on the approach end of the
runway. A steeper-than-normal approach is
required. Crow is a setup in which the flaps
are lowered as normal, but you also raise the
ailerons, thereby creating more drag. This
technique has been used successfully by the
sailplane fraternity.
It works by effectively increasing the drag
so I get a much steeper approach. My model
does not require any pitch-trim correction
when flying with regular flaps, but when I add
the aileron-up of crow, I get a huge upelevator
pitch effect.
I have a program mix of 18% downelevator
with crow application. There is a
good, straight-pitch transition with flap/crow
application, and a nice, steep approach,
allowing me to fly from this—by jet
standards—tight field.
I hope some of this can help you with your
model flying. I look forward to seeing you at
the next jet meet. MA
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