114 MODEL AVIATION
GOING AROUND in Circles: FF
models, Indoor and Outdoor types, fly in
circles. For Indoor models, a circular
flight path is necessary to avoid hitting the
walls. For Outdoor models, circling helps
to keep the airplane on the field longer
and allows it to better take advantage of
thermals.
Setting up a FF model for circular
flight is also easier than trying to adjust an
aircraft to fly in a straight line. The only
FF models that are designed for a straight
flight path are speed airplanes and F1E
Slope Soaring Gliders.
For the former, speed is measured
between two lines, so a straight path
minimizes the distance flown. Trimming a
rubber-powered speed model for straight
flight requires accurate construction and
careful balancing of torque from the
rubber motor.
For F1E, a magnet steering device is
used to hold the flight on a predetermined
compass heading to position the model
relative to the slope current. Then a timer
disengages the magnet-controlled rudder,
and the glider circles for the remainder of
the flight.
For the rest of Outdoor FF, models
must be designed to circle. It is this very
nature of circular flight that allows FF
aircraft to fly without control input.
Basically it involves using a variety of
speed-sensitive adjustments to achieve the
desired circular flight path—one that’s not
too tight or too open.
This works because some adjustments,
such as rudder offset, decalage (incidence
deferential), and wing washin or washout
are more effective the faster the model’s
speed. Other adjustments, such as CG
location, thrust offsets, and stabilizer tilt,
are more effective the slower the model
goes.
A typical example of balancing
circular flight using speed-sensitive
adjustments is a Rubber model with right
thrust and left rudder offset. As the model
speeds up—as it might in the first few
seconds after launch when the rubber
motor is at maximum power—the left
rudder will be more effective than the
right thrust offset, and the model will fly
in a straighter, though not necessarily
straight, flight path.
As the model slows—as it would near
the end of the motor run—the right thrust
offset will be more effective than the right
rudder offset, and the model will turn
more tightly to the right.
Another common way to balance a FF
Louis Joyner, 6 Saturday Rd., Mt. Pleasant SC 29464
FREE FLIGHT DURATION
This Swedish Towline Glider from Frank Zaic’s 1959-61 Model Aeronautic Year Book
uses an asymmetrical wing planform, with a slightly longer right panel.
Right main panel on Bob Piserchio’s 1979 Wakefield is 1⁄2 inch longer than left main. It
was flown right-right. Plans are from 1979 NFFS International Planbook.
116 MODEL AVIATION
model’s circular flight is with crossed
controls. Right rudder might be used with
washin on the right wing to create a left
roll. Both of these are adjustments that
increase in effectiveness with increased
speed. If the model begins to turn too
tightly to the right, the left roll caused by
the washin on the right wing will balance
out the right rudder, preventing a spiral
dive to the right.
With any type of adjustment for an
Outdoor FF model, the amount of these onthe-
ground control inputs is slight. Rudder
and stabilizer adjustments are usually
made with 1⁄64 plywood shims or with
screw adjustments. Sometimes a quarter
turn of an 0-80 screw will make a
significant difference in performance.
Asymmetry: Since Outdoor FF models fly
in circles, do they need to be symmetrical?
Are there any advantages?
As with most things, the best answer is
that it depends. Perhaps the biggest factor
is the desired glide-circle diameter. The
tighter the glide turn, the more asymmetry
might help.
Measuring the diameter of a FF model’s
glide circle is difficult. For that reason, the
glide turn is more often measured by the
time it takes to complete one circle. This is
easy to check with a stopwatch simply by
starting the watch when you see the model
directly from the side and then stopping
the watch when you see the same side
again. From that time and an estimate of
the model’s airspeed, you can calculate the
glide circle’s circumference and diameter.
For a Towline Glider with an airspeed
of four meters per second (roughly 13 feet
per second), a 30-second glide circle
would cover 120 meters, giving a glidecircle
diameter of approximately 38.0
meters (roughly 125 feet). Opening up the
turn to give a 60-second glide circle
doubles the distance covered to 240.0
meters and increases the diameter to
approximately 76.0 meters (roughly 250
feet.)
Since the model is flying in a circle, the
Paul Masterman’s Nostalgia Gas model has asymmetrical stabilizer that is one bay
longer on right side. Design is George Fuller’s Stomper. Model flies right-right.
The F1B Wakefield team going to Argentina consists of Roger
Morrell, Alexander Andriukov, and Bob Tymchek.
Members of the United States F1A Glider team for 2005 Free Flight World
Championships are (L-R) Jim Parker, Mike McKeever, and Martyn Cowley.
The F1C Power team is composed of Ken Happersett, John
Warren, and Randy Archer. Team photos by Janna Van Nest.
outer wing has to go farther than the
inboard wing. That means the airspeed
measured on the outboard tip will be
slightly higher than on the inboard tip.
The tighter the glide circle is, the bigger
the difference between the outboard and
inboard tip speed.
The airplane’s span will also affect the
difference in tip speeds. The longer the
span, the more difference there is between
the inboard and outboard tips. For a large
model, the difference can be significant.
A span of 2.5 meters (approximately
98 inches) is fairly typical for modern
F1A Towline Gliders. For a 30-second
glide circle covering 120.0 meters at the
fuselage center, the outer tip will have to
go roughly 7.2 meters farther than the
fuselage. The inner tip will go roughly
8.5 meters less distance than the fuselage.
That means the outer tip has to cover 15.7
meters (approximately 51 feet) more than
the inner tip.
The outboard tip is flying at 4.24
meters per second, the fuselage is at 4.0
meters per second, and the inner tip is at
3.72 meters per second. That’s a
difference in airspeed between the tips of
approximately 0.5 meters per second—a
significant difference.
A more open glide turn will result in
less difference in outboard and inboard
tip airspeeds. A 60-second glide circle,
with the fuselage covering 240.0 meters,
will require the outer tip to cover 246.6
meters and the inner tip to cover 230.9
meters.
The difference between the distance
that the outboard and the inboard tips
have to cover is the same (15.7 meters) as
in the first example, but it takes twice as
long (60 seconds versus 30 seconds) to do
it.
The outer tip is flying at an airspeed of
4.11 meters per second, the fuselage at
4.0 meters per second, and the inner tip is
at 3.85 meters per second. The difference
in airspeed between the tips is 0.26
meters per second (0.85 feet per second),
which is roughly half the difference in the
first example.
With the wingtips flying at different
speeds, their Reynolds numbers will be
different. Assuming a tip chord of 100mm
(approximately 4 inches), the difference
in tip Reynolds numbers for the model in
the tighter glide turn will be roughly 13%.
For the model with the more open glide
turn, the difference is roughly 6.5%.
(Reynolds number is a nondimensional
parameter used to compare fluid flows. A
quick way to calculate the Reynolds
number for an airplane is to multiply the
chord in millimeters by the velocity in
meters per second by a constant of 70.)
The reason to concern ourselves with
Reynolds numbers is that airfoils—
especially the undercambered, high-lift,
low-speed variety we often use in FF—
behave differently at different Reynolds
numbers.
For a model with a long wing that will
be flown in a tight glide circle, there
might be a benefit in using slightly
different tip airfoils on the inboard and
outboard tips. Or there might be a small
advantage in using different turbulator
sizes or positions on the different tips. In
other words, the airfoil for each portion of
the wing could be optimized.
Obviously, if you launch the model in
a big thermal, that’s not going to matter.
But if you are fighting for every second in
an early-morning flyoff, it could mean the
difference between first or second place.
Another way to use asymmetry is to
make the inboard side of a wing or
stabilizer larger than the other to
counterbalance torque under power or the
turning effect of the rudder. The idea is
that the extra lift of the inner wing would
keep it up in a turn, preventing a spiral
dive, and that it would be somewhat less
sensitive to speed than the more common
method of washing in the inner tip.
A formula for determining how much
longer the inner wing should be is the
span squared divided by six times the
radius of the glide turn. A look through
some old Zaic Year Books turns up a
few instances of this one-wing-longerthan-
the-other approach, especially for
Hand Launched Gliders.
Even though the wingspans are small
(typically 18-20 inches), the models are
flown in extremely tight glide circles.
But the easier and more common
approach is to skew the wing slightly
(approximately 1⁄64 inch on a 4-inch
chord).
In the early 1960s my brother Bud
and I experimented with asymmetrical
dihedral on Hand Launched Gliders.
The models were typical except that the
left wing was V-dihedral and the right
side was polyhedral. It looked funny but
it worked. The models were flown rightright,
and the polyhedral side was more
effective at keeping the inboard wing up
in a thermal.
The great thing about Hand
Launched and Catapult Gliders is that
the models are inexpensive and quick to
build. That makes experimentation
easier.
2005 United States Free Flight Team:
After three intense days of flying in
October, the US team for the Free
Flight World Championships is set.
In F1A Towline Glider, seven of the
30 fliers maxed out after 14 rounds.
Five made the five- and seven-minute
flyoffs. The top three were Mike
McKeever, Randy Weiler, and Martyn
Cowley.
Randy decided to step down from the
team since he and his wife are expecting
their second child at roughly the same time
the World Champs will be held in
Argentina. That moved Jim Parker onto the
team and made Ken Bauer the alternate.
In F1B Wakefield, nine of the 30
finalists maxed out. Alexander Andriukov
topped the single flyoff with a flight of just
more than seven minutes. Although this is
Alex’s first US-team slot, he is no stranger
to international competition. Flying for his
native Ukraine, he is a three-time World
Champion, three-time World Cup winner,
and four-time European Champion.
Roger Morrell, who edits the popular
SCAT Electronic News Web site
(www.aeromodel.com) was second at just
eight seconds behind Alexander. Rounding
out the team is Bob Tymchek, with Bob
Piserchio as the alternate.
Exactly half of the 24 finalists in F1C
Power maxed out, with seven making the
five-minute round. Going for 10 minutes in
an early-morning flyoff, only two-time
World Champ Randy Archer made the
max, despite the engine blowing at the end
of the run.
Ken Happersett was second at just two
seconds shy of 600 seconds on the flight.
John Warren got the third team spot, and
Dave Shirley is the alternate. MA
Edition: Model Aviation - 2005/02
Page Numbers: 114,116,118,122, 124
Edition: Model Aviation - 2005/02
Page Numbers: 114,116,118,122, 124
114 MODEL AVIATION
GOING AROUND in Circles: FF
models, Indoor and Outdoor types, fly in
circles. For Indoor models, a circular
flight path is necessary to avoid hitting the
walls. For Outdoor models, circling helps
to keep the airplane on the field longer
and allows it to better take advantage of
thermals.
Setting up a FF model for circular
flight is also easier than trying to adjust an
aircraft to fly in a straight line. The only
FF models that are designed for a straight
flight path are speed airplanes and F1E
Slope Soaring Gliders.
For the former, speed is measured
between two lines, so a straight path
minimizes the distance flown. Trimming a
rubber-powered speed model for straight
flight requires accurate construction and
careful balancing of torque from the
rubber motor.
For F1E, a magnet steering device is
used to hold the flight on a predetermined
compass heading to position the model
relative to the slope current. Then a timer
disengages the magnet-controlled rudder,
and the glider circles for the remainder of
the flight.
For the rest of Outdoor FF, models
must be designed to circle. It is this very
nature of circular flight that allows FF
aircraft to fly without control input.
Basically it involves using a variety of
speed-sensitive adjustments to achieve the
desired circular flight path—one that’s not
too tight or too open.
This works because some adjustments,
such as rudder offset, decalage (incidence
deferential), and wing washin or washout
are more effective the faster the model’s
speed. Other adjustments, such as CG
location, thrust offsets, and stabilizer tilt,
are more effective the slower the model
goes.
A typical example of balancing
circular flight using speed-sensitive
adjustments is a Rubber model with right
thrust and left rudder offset. As the model
speeds up—as it might in the first few
seconds after launch when the rubber
motor is at maximum power—the left
rudder will be more effective than the
right thrust offset, and the model will fly
in a straighter, though not necessarily
straight, flight path.
As the model slows—as it would near
the end of the motor run—the right thrust
offset will be more effective than the right
rudder offset, and the model will turn
more tightly to the right.
Another common way to balance a FF
Louis Joyner, 6 Saturday Rd., Mt. Pleasant SC 29464
FREE FLIGHT DURATION
This Swedish Towline Glider from Frank Zaic’s 1959-61 Model Aeronautic Year Book
uses an asymmetrical wing planform, with a slightly longer right panel.
Right main panel on Bob Piserchio’s 1979 Wakefield is 1⁄2 inch longer than left main. It
was flown right-right. Plans are from 1979 NFFS International Planbook.
116 MODEL AVIATION
model’s circular flight is with crossed
controls. Right rudder might be used with
washin on the right wing to create a left
roll. Both of these are adjustments that
increase in effectiveness with increased
speed. If the model begins to turn too
tightly to the right, the left roll caused by
the washin on the right wing will balance
out the right rudder, preventing a spiral
dive to the right.
With any type of adjustment for an
Outdoor FF model, the amount of these onthe-
ground control inputs is slight. Rudder
and stabilizer adjustments are usually
made with 1⁄64 plywood shims or with
screw adjustments. Sometimes a quarter
turn of an 0-80 screw will make a
significant difference in performance.
Asymmetry: Since Outdoor FF models fly
in circles, do they need to be symmetrical?
Are there any advantages?
As with most things, the best answer is
that it depends. Perhaps the biggest factor
is the desired glide-circle diameter. The
tighter the glide turn, the more asymmetry
might help.
Measuring the diameter of a FF model’s
glide circle is difficult. For that reason, the
glide turn is more often measured by the
time it takes to complete one circle. This is
easy to check with a stopwatch simply by
starting the watch when you see the model
directly from the side and then stopping
the watch when you see the same side
again. From that time and an estimate of
the model’s airspeed, you can calculate the
glide circle’s circumference and diameter.
For a Towline Glider with an airspeed
of four meters per second (roughly 13 feet
per second), a 30-second glide circle
would cover 120 meters, giving a glidecircle
diameter of approximately 38.0
meters (roughly 125 feet). Opening up the
turn to give a 60-second glide circle
doubles the distance covered to 240.0
meters and increases the diameter to
approximately 76.0 meters (roughly 250
feet.)
Since the model is flying in a circle, the
Paul Masterman’s Nostalgia Gas model has asymmetrical stabilizer that is one bay
longer on right side. Design is George Fuller’s Stomper. Model flies right-right.
The F1B Wakefield team going to Argentina consists of Roger
Morrell, Alexander Andriukov, and Bob Tymchek.
Members of the United States F1A Glider team for 2005 Free Flight World
Championships are (L-R) Jim Parker, Mike McKeever, and Martyn Cowley.
The F1C Power team is composed of Ken Happersett, John
Warren, and Randy Archer. Team photos by Janna Van Nest.
outer wing has to go farther than the
inboard wing. That means the airspeed
measured on the outboard tip will be
slightly higher than on the inboard tip.
The tighter the glide circle is, the bigger
the difference between the outboard and
inboard tip speed.
The airplane’s span will also affect the
difference in tip speeds. The longer the
span, the more difference there is between
the inboard and outboard tips. For a large
model, the difference can be significant.
A span of 2.5 meters (approximately
98 inches) is fairly typical for modern
F1A Towline Gliders. For a 30-second
glide circle covering 120.0 meters at the
fuselage center, the outer tip will have to
go roughly 7.2 meters farther than the
fuselage. The inner tip will go roughly
8.5 meters less distance than the fuselage.
That means the outer tip has to cover 15.7
meters (approximately 51 feet) more than
the inner tip.
The outboard tip is flying at 4.24
meters per second, the fuselage is at 4.0
meters per second, and the inner tip is at
3.72 meters per second. That’s a
difference in airspeed between the tips of
approximately 0.5 meters per second—a
significant difference.
A more open glide turn will result in
less difference in outboard and inboard
tip airspeeds. A 60-second glide circle,
with the fuselage covering 240.0 meters,
will require the outer tip to cover 246.6
meters and the inner tip to cover 230.9
meters.
The difference between the distance
that the outboard and the inboard tips
have to cover is the same (15.7 meters) as
in the first example, but it takes twice as
long (60 seconds versus 30 seconds) to do
it.
The outer tip is flying at an airspeed of
4.11 meters per second, the fuselage at
4.0 meters per second, and the inner tip is
at 3.85 meters per second. The difference
in airspeed between the tips is 0.26
meters per second (0.85 feet per second),
which is roughly half the difference in the
first example.
With the wingtips flying at different
speeds, their Reynolds numbers will be
different. Assuming a tip chord of 100mm
(approximately 4 inches), the difference
in tip Reynolds numbers for the model in
the tighter glide turn will be roughly 13%.
For the model with the more open glide
turn, the difference is roughly 6.5%.
(Reynolds number is a nondimensional
parameter used to compare fluid flows. A
quick way to calculate the Reynolds
number for an airplane is to multiply the
chord in millimeters by the velocity in
meters per second by a constant of 70.)
The reason to concern ourselves with
Reynolds numbers is that airfoils—
especially the undercambered, high-lift,
low-speed variety we often use in FF—
behave differently at different Reynolds
numbers.
For a model with a long wing that will
be flown in a tight glide circle, there
might be a benefit in using slightly
different tip airfoils on the inboard and
outboard tips. Or there might be a small
advantage in using different turbulator
sizes or positions on the different tips. In
other words, the airfoil for each portion of
the wing could be optimized.
Obviously, if you launch the model in
a big thermal, that’s not going to matter.
But if you are fighting for every second in
an early-morning flyoff, it could mean the
difference between first or second place.
Another way to use asymmetry is to
make the inboard side of a wing or
stabilizer larger than the other to
counterbalance torque under power or the
turning effect of the rudder. The idea is
that the extra lift of the inner wing would
keep it up in a turn, preventing a spiral
dive, and that it would be somewhat less
sensitive to speed than the more common
method of washing in the inner tip.
A formula for determining how much
longer the inner wing should be is the
span squared divided by six times the
radius of the glide turn. A look through
some old Zaic Year Books turns up a
few instances of this one-wing-longerthan-
the-other approach, especially for
Hand Launched Gliders.
Even though the wingspans are small
(typically 18-20 inches), the models are
flown in extremely tight glide circles.
But the easier and more common
approach is to skew the wing slightly
(approximately 1⁄64 inch on a 4-inch
chord).
In the early 1960s my brother Bud
and I experimented with asymmetrical
dihedral on Hand Launched Gliders.
The models were typical except that the
left wing was V-dihedral and the right
side was polyhedral. It looked funny but
it worked. The models were flown rightright,
and the polyhedral side was more
effective at keeping the inboard wing up
in a thermal.
The great thing about Hand
Launched and Catapult Gliders is that
the models are inexpensive and quick to
build. That makes experimentation
easier.
2005 United States Free Flight Team:
After three intense days of flying in
October, the US team for the Free
Flight World Championships is set.
In F1A Towline Glider, seven of the
30 fliers maxed out after 14 rounds.
Five made the five- and seven-minute
flyoffs. The top three were Mike
McKeever, Randy Weiler, and Martyn
Cowley.
Randy decided to step down from the
team since he and his wife are expecting
their second child at roughly the same time
the World Champs will be held in
Argentina. That moved Jim Parker onto the
team and made Ken Bauer the alternate.
In F1B Wakefield, nine of the 30
finalists maxed out. Alexander Andriukov
topped the single flyoff with a flight of just
more than seven minutes. Although this is
Alex’s first US-team slot, he is no stranger
to international competition. Flying for his
native Ukraine, he is a three-time World
Champion, three-time World Cup winner,
and four-time European Champion.
Roger Morrell, who edits the popular
SCAT Electronic News Web site
(www.aeromodel.com) was second at just
eight seconds behind Alexander. Rounding
out the team is Bob Tymchek, with Bob
Piserchio as the alternate.
Exactly half of the 24 finalists in F1C
Power maxed out, with seven making the
five-minute round. Going for 10 minutes in
an early-morning flyoff, only two-time
World Champ Randy Archer made the
max, despite the engine blowing at the end
of the run.
Ken Happersett was second at just two
seconds shy of 600 seconds on the flight.
John Warren got the third team spot, and
Dave Shirley is the alternate. MA
Edition: Model Aviation - 2005/02
Page Numbers: 114,116,118,122, 124
114 MODEL AVIATION
GOING AROUND in Circles: FF
models, Indoor and Outdoor types, fly in
circles. For Indoor models, a circular
flight path is necessary to avoid hitting the
walls. For Outdoor models, circling helps
to keep the airplane on the field longer
and allows it to better take advantage of
thermals.
Setting up a FF model for circular
flight is also easier than trying to adjust an
aircraft to fly in a straight line. The only
FF models that are designed for a straight
flight path are speed airplanes and F1E
Slope Soaring Gliders.
For the former, speed is measured
between two lines, so a straight path
minimizes the distance flown. Trimming a
rubber-powered speed model for straight
flight requires accurate construction and
careful balancing of torque from the
rubber motor.
For F1E, a magnet steering device is
used to hold the flight on a predetermined
compass heading to position the model
relative to the slope current. Then a timer
disengages the magnet-controlled rudder,
and the glider circles for the remainder of
the flight.
For the rest of Outdoor FF, models
must be designed to circle. It is this very
nature of circular flight that allows FF
aircraft to fly without control input.
Basically it involves using a variety of
speed-sensitive adjustments to achieve the
desired circular flight path—one that’s not
too tight or too open.
This works because some adjustments,
such as rudder offset, decalage (incidence
deferential), and wing washin or washout
are more effective the faster the model’s
speed. Other adjustments, such as CG
location, thrust offsets, and stabilizer tilt,
are more effective the slower the model
goes.
A typical example of balancing
circular flight using speed-sensitive
adjustments is a Rubber model with right
thrust and left rudder offset. As the model
speeds up—as it might in the first few
seconds after launch when the rubber
motor is at maximum power—the left
rudder will be more effective than the
right thrust offset, and the model will fly
in a straighter, though not necessarily
straight, flight path.
As the model slows—as it would near
the end of the motor run—the right thrust
offset will be more effective than the right
rudder offset, and the model will turn
more tightly to the right.
Another common way to balance a FF
Louis Joyner, 6 Saturday Rd., Mt. Pleasant SC 29464
FREE FLIGHT DURATION
This Swedish Towline Glider from Frank Zaic’s 1959-61 Model Aeronautic Year Book
uses an asymmetrical wing planform, with a slightly longer right panel.
Right main panel on Bob Piserchio’s 1979 Wakefield is 1⁄2 inch longer than left main. It
was flown right-right. Plans are from 1979 NFFS International Planbook.
116 MODEL AVIATION
model’s circular flight is with crossed
controls. Right rudder might be used with
washin on the right wing to create a left
roll. Both of these are adjustments that
increase in effectiveness with increased
speed. If the model begins to turn too
tightly to the right, the left roll caused by
the washin on the right wing will balance
out the right rudder, preventing a spiral
dive to the right.
With any type of adjustment for an
Outdoor FF model, the amount of these onthe-
ground control inputs is slight. Rudder
and stabilizer adjustments are usually
made with 1⁄64 plywood shims or with
screw adjustments. Sometimes a quarter
turn of an 0-80 screw will make a
significant difference in performance.
Asymmetry: Since Outdoor FF models fly
in circles, do they need to be symmetrical?
Are there any advantages?
As with most things, the best answer is
that it depends. Perhaps the biggest factor
is the desired glide-circle diameter. The
tighter the glide turn, the more asymmetry
might help.
Measuring the diameter of a FF model’s
glide circle is difficult. For that reason, the
glide turn is more often measured by the
time it takes to complete one circle. This is
easy to check with a stopwatch simply by
starting the watch when you see the model
directly from the side and then stopping
the watch when you see the same side
again. From that time and an estimate of
the model’s airspeed, you can calculate the
glide circle’s circumference and diameter.
For a Towline Glider with an airspeed
of four meters per second (roughly 13 feet
per second), a 30-second glide circle
would cover 120 meters, giving a glidecircle
diameter of approximately 38.0
meters (roughly 125 feet). Opening up the
turn to give a 60-second glide circle
doubles the distance covered to 240.0
meters and increases the diameter to
approximately 76.0 meters (roughly 250
feet.)
Since the model is flying in a circle, the
Paul Masterman’s Nostalgia Gas model has asymmetrical stabilizer that is one bay
longer on right side. Design is George Fuller’s Stomper. Model flies right-right.
The F1B Wakefield team going to Argentina consists of Roger
Morrell, Alexander Andriukov, and Bob Tymchek.
Members of the United States F1A Glider team for 2005 Free Flight World
Championships are (L-R) Jim Parker, Mike McKeever, and Martyn Cowley.
The F1C Power team is composed of Ken Happersett, John
Warren, and Randy Archer. Team photos by Janna Van Nest.
outer wing has to go farther than the
inboard wing. That means the airspeed
measured on the outboard tip will be
slightly higher than on the inboard tip.
The tighter the glide circle is, the bigger
the difference between the outboard and
inboard tip speed.
The airplane’s span will also affect the
difference in tip speeds. The longer the
span, the more difference there is between
the inboard and outboard tips. For a large
model, the difference can be significant.
A span of 2.5 meters (approximately
98 inches) is fairly typical for modern
F1A Towline Gliders. For a 30-second
glide circle covering 120.0 meters at the
fuselage center, the outer tip will have to
go roughly 7.2 meters farther than the
fuselage. The inner tip will go roughly
8.5 meters less distance than the fuselage.
That means the outer tip has to cover 15.7
meters (approximately 51 feet) more than
the inner tip.
The outboard tip is flying at 4.24
meters per second, the fuselage is at 4.0
meters per second, and the inner tip is at
3.72 meters per second. That’s a
difference in airspeed between the tips of
approximately 0.5 meters per second—a
significant difference.
A more open glide turn will result in
less difference in outboard and inboard
tip airspeeds. A 60-second glide circle,
with the fuselage covering 240.0 meters,
will require the outer tip to cover 246.6
meters and the inner tip to cover 230.9
meters.
The difference between the distance
that the outboard and the inboard tips
have to cover is the same (15.7 meters) as
in the first example, but it takes twice as
long (60 seconds versus 30 seconds) to do
it.
The outer tip is flying at an airspeed of
4.11 meters per second, the fuselage at
4.0 meters per second, and the inner tip is
at 3.85 meters per second. The difference
in airspeed between the tips is 0.26
meters per second (0.85 feet per second),
which is roughly half the difference in the
first example.
With the wingtips flying at different
speeds, their Reynolds numbers will be
different. Assuming a tip chord of 100mm
(approximately 4 inches), the difference
in tip Reynolds numbers for the model in
the tighter glide turn will be roughly 13%.
For the model with the more open glide
turn, the difference is roughly 6.5%.
(Reynolds number is a nondimensional
parameter used to compare fluid flows. A
quick way to calculate the Reynolds
number for an airplane is to multiply the
chord in millimeters by the velocity in
meters per second by a constant of 70.)
The reason to concern ourselves with
Reynolds numbers is that airfoils—
especially the undercambered, high-lift,
low-speed variety we often use in FF—
behave differently at different Reynolds
numbers.
For a model with a long wing that will
be flown in a tight glide circle, there
might be a benefit in using slightly
different tip airfoils on the inboard and
outboard tips. Or there might be a small
advantage in using different turbulator
sizes or positions on the different tips. In
other words, the airfoil for each portion of
the wing could be optimized.
Obviously, if you launch the model in
a big thermal, that’s not going to matter.
But if you are fighting for every second in
an early-morning flyoff, it could mean the
difference between first or second place.
Another way to use asymmetry is to
make the inboard side of a wing or
stabilizer larger than the other to
counterbalance torque under power or the
turning effect of the rudder. The idea is
that the extra lift of the inner wing would
keep it up in a turn, preventing a spiral
dive, and that it would be somewhat less
sensitive to speed than the more common
method of washing in the inner tip.
A formula for determining how much
longer the inner wing should be is the
span squared divided by six times the
radius of the glide turn. A look through
some old Zaic Year Books turns up a
few instances of this one-wing-longerthan-
the-other approach, especially for
Hand Launched Gliders.
Even though the wingspans are small
(typically 18-20 inches), the models are
flown in extremely tight glide circles.
But the easier and more common
approach is to skew the wing slightly
(approximately 1⁄64 inch on a 4-inch
chord).
In the early 1960s my brother Bud
and I experimented with asymmetrical
dihedral on Hand Launched Gliders.
The models were typical except that the
left wing was V-dihedral and the right
side was polyhedral. It looked funny but
it worked. The models were flown rightright,
and the polyhedral side was more
effective at keeping the inboard wing up
in a thermal.
The great thing about Hand
Launched and Catapult Gliders is that
the models are inexpensive and quick to
build. That makes experimentation
easier.
2005 United States Free Flight Team:
After three intense days of flying in
October, the US team for the Free
Flight World Championships is set.
In F1A Towline Glider, seven of the
30 fliers maxed out after 14 rounds.
Five made the five- and seven-minute
flyoffs. The top three were Mike
McKeever, Randy Weiler, and Martyn
Cowley.
Randy decided to step down from the
team since he and his wife are expecting
their second child at roughly the same time
the World Champs will be held in
Argentina. That moved Jim Parker onto the
team and made Ken Bauer the alternate.
In F1B Wakefield, nine of the 30
finalists maxed out. Alexander Andriukov
topped the single flyoff with a flight of just
more than seven minutes. Although this is
Alex’s first US-team slot, he is no stranger
to international competition. Flying for his
native Ukraine, he is a three-time World
Champion, three-time World Cup winner,
and four-time European Champion.
Roger Morrell, who edits the popular
SCAT Electronic News Web site
(www.aeromodel.com) was second at just
eight seconds behind Alexander. Rounding
out the team is Bob Tymchek, with Bob
Piserchio as the alternate.
Exactly half of the 24 finalists in F1C
Power maxed out, with seven making the
five-minute round. Going for 10 minutes in
an early-morning flyoff, only two-time
World Champ Randy Archer made the
max, despite the engine blowing at the end
of the run.
Ken Happersett was second at just two
seconds shy of 600 seconds on the flight.
John Warren got the third team spot, and
Dave Shirley is the alternate. MA
Edition: Model Aviation - 2005/02
Page Numbers: 114,116,118,122, 124
114 MODEL AVIATION
GOING AROUND in Circles: FF
models, Indoor and Outdoor types, fly in
circles. For Indoor models, a circular
flight path is necessary to avoid hitting the
walls. For Outdoor models, circling helps
to keep the airplane on the field longer
and allows it to better take advantage of
thermals.
Setting up a FF model for circular
flight is also easier than trying to adjust an
aircraft to fly in a straight line. The only
FF models that are designed for a straight
flight path are speed airplanes and F1E
Slope Soaring Gliders.
For the former, speed is measured
between two lines, so a straight path
minimizes the distance flown. Trimming a
rubber-powered speed model for straight
flight requires accurate construction and
careful balancing of torque from the
rubber motor.
For F1E, a magnet steering device is
used to hold the flight on a predetermined
compass heading to position the model
relative to the slope current. Then a timer
disengages the magnet-controlled rudder,
and the glider circles for the remainder of
the flight.
For the rest of Outdoor FF, models
must be designed to circle. It is this very
nature of circular flight that allows FF
aircraft to fly without control input.
Basically it involves using a variety of
speed-sensitive adjustments to achieve the
desired circular flight path—one that’s not
too tight or too open.
This works because some adjustments,
such as rudder offset, decalage (incidence
deferential), and wing washin or washout
are more effective the faster the model’s
speed. Other adjustments, such as CG
location, thrust offsets, and stabilizer tilt,
are more effective the slower the model
goes.
A typical example of balancing
circular flight using speed-sensitive
adjustments is a Rubber model with right
thrust and left rudder offset. As the model
speeds up—as it might in the first few
seconds after launch when the rubber
motor is at maximum power—the left
rudder will be more effective than the
right thrust offset, and the model will fly
in a straighter, though not necessarily
straight, flight path.
As the model slows—as it would near
the end of the motor run—the right thrust
offset will be more effective than the right
rudder offset, and the model will turn
more tightly to the right.
Another common way to balance a FF
Louis Joyner, 6 Saturday Rd., Mt. Pleasant SC 29464
FREE FLIGHT DURATION
This Swedish Towline Glider from Frank Zaic’s 1959-61 Model Aeronautic Year Book
uses an asymmetrical wing planform, with a slightly longer right panel.
Right main panel on Bob Piserchio’s 1979 Wakefield is 1⁄2 inch longer than left main. It
was flown right-right. Plans are from 1979 NFFS International Planbook.
116 MODEL AVIATION
model’s circular flight is with crossed
controls. Right rudder might be used with
washin on the right wing to create a left
roll. Both of these are adjustments that
increase in effectiveness with increased
speed. If the model begins to turn too
tightly to the right, the left roll caused by
the washin on the right wing will balance
out the right rudder, preventing a spiral
dive to the right.
With any type of adjustment for an
Outdoor FF model, the amount of these onthe-
ground control inputs is slight. Rudder
and stabilizer adjustments are usually
made with 1⁄64 plywood shims or with
screw adjustments. Sometimes a quarter
turn of an 0-80 screw will make a
significant difference in performance.
Asymmetry: Since Outdoor FF models fly
in circles, do they need to be symmetrical?
Are there any advantages?
As with most things, the best answer is
that it depends. Perhaps the biggest factor
is the desired glide-circle diameter. The
tighter the glide turn, the more asymmetry
might help.
Measuring the diameter of a FF model’s
glide circle is difficult. For that reason, the
glide turn is more often measured by the
time it takes to complete one circle. This is
easy to check with a stopwatch simply by
starting the watch when you see the model
directly from the side and then stopping
the watch when you see the same side
again. From that time and an estimate of
the model’s airspeed, you can calculate the
glide circle’s circumference and diameter.
For a Towline Glider with an airspeed
of four meters per second (roughly 13 feet
per second), a 30-second glide circle
would cover 120 meters, giving a glidecircle
diameter of approximately 38.0
meters (roughly 125 feet). Opening up the
turn to give a 60-second glide circle
doubles the distance covered to 240.0
meters and increases the diameter to
approximately 76.0 meters (roughly 250
feet.)
Since the model is flying in a circle, the
Paul Masterman’s Nostalgia Gas model has asymmetrical stabilizer that is one bay
longer on right side. Design is George Fuller’s Stomper. Model flies right-right.
The F1B Wakefield team going to Argentina consists of Roger
Morrell, Alexander Andriukov, and Bob Tymchek.
Members of the United States F1A Glider team for 2005 Free Flight World
Championships are (L-R) Jim Parker, Mike McKeever, and Martyn Cowley.
The F1C Power team is composed of Ken Happersett, John
Warren, and Randy Archer. Team photos by Janna Van Nest.
outer wing has to go farther than the
inboard wing. That means the airspeed
measured on the outboard tip will be
slightly higher than on the inboard tip.
The tighter the glide circle is, the bigger
the difference between the outboard and
inboard tip speed.
The airplane’s span will also affect the
difference in tip speeds. The longer the
span, the more difference there is between
the inboard and outboard tips. For a large
model, the difference can be significant.
A span of 2.5 meters (approximately
98 inches) is fairly typical for modern
F1A Towline Gliders. For a 30-second
glide circle covering 120.0 meters at the
fuselage center, the outer tip will have to
go roughly 7.2 meters farther than the
fuselage. The inner tip will go roughly
8.5 meters less distance than the fuselage.
That means the outer tip has to cover 15.7
meters (approximately 51 feet) more than
the inner tip.
The outboard tip is flying at 4.24
meters per second, the fuselage is at 4.0
meters per second, and the inner tip is at
3.72 meters per second. That’s a
difference in airspeed between the tips of
approximately 0.5 meters per second—a
significant difference.
A more open glide turn will result in
less difference in outboard and inboard
tip airspeeds. A 60-second glide circle,
with the fuselage covering 240.0 meters,
will require the outer tip to cover 246.6
meters and the inner tip to cover 230.9
meters.
The difference between the distance
that the outboard and the inboard tips
have to cover is the same (15.7 meters) as
in the first example, but it takes twice as
long (60 seconds versus 30 seconds) to do
it.
The outer tip is flying at an airspeed of
4.11 meters per second, the fuselage at
4.0 meters per second, and the inner tip is
at 3.85 meters per second. The difference
in airspeed between the tips is 0.26
meters per second (0.85 feet per second),
which is roughly half the difference in the
first example.
With the wingtips flying at different
speeds, their Reynolds numbers will be
different. Assuming a tip chord of 100mm
(approximately 4 inches), the difference
in tip Reynolds numbers for the model in
the tighter glide turn will be roughly 13%.
For the model with the more open glide
turn, the difference is roughly 6.5%.
(Reynolds number is a nondimensional
parameter used to compare fluid flows. A
quick way to calculate the Reynolds
number for an airplane is to multiply the
chord in millimeters by the velocity in
meters per second by a constant of 70.)
The reason to concern ourselves with
Reynolds numbers is that airfoils—
especially the undercambered, high-lift,
low-speed variety we often use in FF—
behave differently at different Reynolds
numbers.
For a model with a long wing that will
be flown in a tight glide circle, there
might be a benefit in using slightly
different tip airfoils on the inboard and
outboard tips. Or there might be a small
advantage in using different turbulator
sizes or positions on the different tips. In
other words, the airfoil for each portion of
the wing could be optimized.
Obviously, if you launch the model in
a big thermal, that’s not going to matter.
But if you are fighting for every second in
an early-morning flyoff, it could mean the
difference between first or second place.
Another way to use asymmetry is to
make the inboard side of a wing or
stabilizer larger than the other to
counterbalance torque under power or the
turning effect of the rudder. The idea is
that the extra lift of the inner wing would
keep it up in a turn, preventing a spiral
dive, and that it would be somewhat less
sensitive to speed than the more common
method of washing in the inner tip.
A formula for determining how much
longer the inner wing should be is the
span squared divided by six times the
radius of the glide turn. A look through
some old Zaic Year Books turns up a
few instances of this one-wing-longerthan-
the-other approach, especially for
Hand Launched Gliders.
Even though the wingspans are small
(typically 18-20 inches), the models are
flown in extremely tight glide circles.
But the easier and more common
approach is to skew the wing slightly
(approximately 1⁄64 inch on a 4-inch
chord).
In the early 1960s my brother Bud
and I experimented with asymmetrical
dihedral on Hand Launched Gliders.
The models were typical except that the
left wing was V-dihedral and the right
side was polyhedral. It looked funny but
it worked. The models were flown rightright,
and the polyhedral side was more
effective at keeping the inboard wing up
in a thermal.
The great thing about Hand
Launched and Catapult Gliders is that
the models are inexpensive and quick to
build. That makes experimentation
easier.
2005 United States Free Flight Team:
After three intense days of flying in
October, the US team for the Free
Flight World Championships is set.
In F1A Towline Glider, seven of the
30 fliers maxed out after 14 rounds.
Five made the five- and seven-minute
flyoffs. The top three were Mike
McKeever, Randy Weiler, and Martyn
Cowley.
Randy decided to step down from the
team since he and his wife are expecting
their second child at roughly the same time
the World Champs will be held in
Argentina. That moved Jim Parker onto the
team and made Ken Bauer the alternate.
In F1B Wakefield, nine of the 30
finalists maxed out. Alexander Andriukov
topped the single flyoff with a flight of just
more than seven minutes. Although this is
Alex’s first US-team slot, he is no stranger
to international competition. Flying for his
native Ukraine, he is a three-time World
Champion, three-time World Cup winner,
and four-time European Champion.
Roger Morrell, who edits the popular
SCAT Electronic News Web site
(www.aeromodel.com) was second at just
eight seconds behind Alexander. Rounding
out the team is Bob Tymchek, with Bob
Piserchio as the alternate.
Exactly half of the 24 finalists in F1C
Power maxed out, with seven making the
five-minute round. Going for 10 minutes in
an early-morning flyoff, only two-time
World Champ Randy Archer made the
max, despite the engine blowing at the end
of the run.
Ken Happersett was second at just two
seconds shy of 600 seconds on the flight.
John Warren got the third team spot, and
Dave Shirley is the alternate. MA
Edition: Model Aviation - 2005/02
Page Numbers: 114,116,118,122, 124
114 MODEL AVIATION
GOING AROUND in Circles: FF
models, Indoor and Outdoor types, fly in
circles. For Indoor models, a circular
flight path is necessary to avoid hitting the
walls. For Outdoor models, circling helps
to keep the airplane on the field longer
and allows it to better take advantage of
thermals.
Setting up a FF model for circular
flight is also easier than trying to adjust an
aircraft to fly in a straight line. The only
FF models that are designed for a straight
flight path are speed airplanes and F1E
Slope Soaring Gliders.
For the former, speed is measured
between two lines, so a straight path
minimizes the distance flown. Trimming a
rubber-powered speed model for straight
flight requires accurate construction and
careful balancing of torque from the
rubber motor.
For F1E, a magnet steering device is
used to hold the flight on a predetermined
compass heading to position the model
relative to the slope current. Then a timer
disengages the magnet-controlled rudder,
and the glider circles for the remainder of
the flight.
For the rest of Outdoor FF, models
must be designed to circle. It is this very
nature of circular flight that allows FF
aircraft to fly without control input.
Basically it involves using a variety of
speed-sensitive adjustments to achieve the
desired circular flight path—one that’s not
too tight or too open.
This works because some adjustments,
such as rudder offset, decalage (incidence
deferential), and wing washin or washout
are more effective the faster the model’s
speed. Other adjustments, such as CG
location, thrust offsets, and stabilizer tilt,
are more effective the slower the model
goes.
A typical example of balancing
circular flight using speed-sensitive
adjustments is a Rubber model with right
thrust and left rudder offset. As the model
speeds up—as it might in the first few
seconds after launch when the rubber
motor is at maximum power—the left
rudder will be more effective than the
right thrust offset, and the model will fly
in a straighter, though not necessarily
straight, flight path.
As the model slows—as it would near
the end of the motor run—the right thrust
offset will be more effective than the right
rudder offset, and the model will turn
more tightly to the right.
Another common way to balance a FF
Louis Joyner, 6 Saturday Rd., Mt. Pleasant SC 29464
FREE FLIGHT DURATION
This Swedish Towline Glider from Frank Zaic’s 1959-61 Model Aeronautic Year Book
uses an asymmetrical wing planform, with a slightly longer right panel.
Right main panel on Bob Piserchio’s 1979 Wakefield is 1⁄2 inch longer than left main. It
was flown right-right. Plans are from 1979 NFFS International Planbook.
116 MODEL AVIATION
model’s circular flight is with crossed
controls. Right rudder might be used with
washin on the right wing to create a left
roll. Both of these are adjustments that
increase in effectiveness with increased
speed. If the model begins to turn too
tightly to the right, the left roll caused by
the washin on the right wing will balance
out the right rudder, preventing a spiral
dive to the right.
With any type of adjustment for an
Outdoor FF model, the amount of these onthe-
ground control inputs is slight. Rudder
and stabilizer adjustments are usually
made with 1⁄64 plywood shims or with
screw adjustments. Sometimes a quarter
turn of an 0-80 screw will make a
significant difference in performance.
Asymmetry: Since Outdoor FF models fly
in circles, do they need to be symmetrical?
Are there any advantages?
As with most things, the best answer is
that it depends. Perhaps the biggest factor
is the desired glide-circle diameter. The
tighter the glide turn, the more asymmetry
might help.
Measuring the diameter of a FF model’s
glide circle is difficult. For that reason, the
glide turn is more often measured by the
time it takes to complete one circle. This is
easy to check with a stopwatch simply by
starting the watch when you see the model
directly from the side and then stopping
the watch when you see the same side
again. From that time and an estimate of
the model’s airspeed, you can calculate the
glide circle’s circumference and diameter.
For a Towline Glider with an airspeed
of four meters per second (roughly 13 feet
per second), a 30-second glide circle
would cover 120 meters, giving a glidecircle
diameter of approximately 38.0
meters (roughly 125 feet). Opening up the
turn to give a 60-second glide circle
doubles the distance covered to 240.0
meters and increases the diameter to
approximately 76.0 meters (roughly 250
feet.)
Since the model is flying in a circle, the
Paul Masterman’s Nostalgia Gas model has asymmetrical stabilizer that is one bay
longer on right side. Design is George Fuller’s Stomper. Model flies right-right.
The F1B Wakefield team going to Argentina consists of Roger
Morrell, Alexander Andriukov, and Bob Tymchek.
Members of the United States F1A Glider team for 2005 Free Flight World
Championships are (L-R) Jim Parker, Mike McKeever, and Martyn Cowley.
The F1C Power team is composed of Ken Happersett, John
Warren, and Randy Archer. Team photos by Janna Van Nest.
outer wing has to go farther than the
inboard wing. That means the airspeed
measured on the outboard tip will be
slightly higher than on the inboard tip.
The tighter the glide circle is, the bigger
the difference between the outboard and
inboard tip speed.
The airplane’s span will also affect the
difference in tip speeds. The longer the
span, the more difference there is between
the inboard and outboard tips. For a large
model, the difference can be significant.
A span of 2.5 meters (approximately
98 inches) is fairly typical for modern
F1A Towline Gliders. For a 30-second
glide circle covering 120.0 meters at the
fuselage center, the outer tip will have to
go roughly 7.2 meters farther than the
fuselage. The inner tip will go roughly
8.5 meters less distance than the fuselage.
That means the outer tip has to cover 15.7
meters (approximately 51 feet) more than
the inner tip.
The outboard tip is flying at 4.24
meters per second, the fuselage is at 4.0
meters per second, and the inner tip is at
3.72 meters per second. That’s a
difference in airspeed between the tips of
approximately 0.5 meters per second—a
significant difference.
A more open glide turn will result in
less difference in outboard and inboard
tip airspeeds. A 60-second glide circle,
with the fuselage covering 240.0 meters,
will require the outer tip to cover 246.6
meters and the inner tip to cover 230.9
meters.
The difference between the distance
that the outboard and the inboard tips
have to cover is the same (15.7 meters) as
in the first example, but it takes twice as
long (60 seconds versus 30 seconds) to do
it.
The outer tip is flying at an airspeed of
4.11 meters per second, the fuselage at
4.0 meters per second, and the inner tip is
at 3.85 meters per second. The difference
in airspeed between the tips is 0.26
meters per second (0.85 feet per second),
which is roughly half the difference in the
first example.
With the wingtips flying at different
speeds, their Reynolds numbers will be
different. Assuming a tip chord of 100mm
(approximately 4 inches), the difference
in tip Reynolds numbers for the model in
the tighter glide turn will be roughly 13%.
For the model with the more open glide
turn, the difference is roughly 6.5%.
(Reynolds number is a nondimensional
parameter used to compare fluid flows. A
quick way to calculate the Reynolds
number for an airplane is to multiply the
chord in millimeters by the velocity in
meters per second by a constant of 70.)
The reason to concern ourselves with
Reynolds numbers is that airfoils—
especially the undercambered, high-lift,
low-speed variety we often use in FF—
behave differently at different Reynolds
numbers.
For a model with a long wing that will
be flown in a tight glide circle, there
might be a benefit in using slightly
different tip airfoils on the inboard and
outboard tips. Or there might be a small
advantage in using different turbulator
sizes or positions on the different tips. In
other words, the airfoil for each portion of
the wing could be optimized.
Obviously, if you launch the model in
a big thermal, that’s not going to matter.
But if you are fighting for every second in
an early-morning flyoff, it could mean the
difference between first or second place.
Another way to use asymmetry is to
make the inboard side of a wing or
stabilizer larger than the other to
counterbalance torque under power or the
turning effect of the rudder. The idea is
that the extra lift of the inner wing would
keep it up in a turn, preventing a spiral
dive, and that it would be somewhat less
sensitive to speed than the more common
method of washing in the inner tip.
A formula for determining how much
longer the inner wing should be is the
span squared divided by six times the
radius of the glide turn. A look through
some old Zaic Year Books turns up a
few instances of this one-wing-longerthan-
the-other approach, especially for
Hand Launched Gliders.
Even though the wingspans are small
(typically 18-20 inches), the models are
flown in extremely tight glide circles.
But the easier and more common
approach is to skew the wing slightly
(approximately 1⁄64 inch on a 4-inch
chord).
In the early 1960s my brother Bud
and I experimented with asymmetrical
dihedral on Hand Launched Gliders.
The models were typical except that the
left wing was V-dihedral and the right
side was polyhedral. It looked funny but
it worked. The models were flown rightright,
and the polyhedral side was more
effective at keeping the inboard wing up
in a thermal.
The great thing about Hand
Launched and Catapult Gliders is that
the models are inexpensive and quick to
build. That makes experimentation
easier.
2005 United States Free Flight Team:
After three intense days of flying in
October, the US team for the Free
Flight World Championships is set.
In F1A Towline Glider, seven of the
30 fliers maxed out after 14 rounds.
Five made the five- and seven-minute
flyoffs. The top three were Mike
McKeever, Randy Weiler, and Martyn
Cowley.
Randy decided to step down from the
team since he and his wife are expecting
their second child at roughly the same time
the World Champs will be held in
Argentina. That moved Jim Parker onto the
team and made Ken Bauer the alternate.
In F1B Wakefield, nine of the 30
finalists maxed out. Alexander Andriukov
topped the single flyoff with a flight of just
more than seven minutes. Although this is
Alex’s first US-team slot, he is no stranger
to international competition. Flying for his
native Ukraine, he is a three-time World
Champion, three-time World Cup winner,
and four-time European Champion.
Roger Morrell, who edits the popular
SCAT Electronic News Web site
(www.aeromodel.com) was second at just
eight seconds behind Alexander. Rounding
out the team is Bob Tymchek, with Bob
Piserchio as the alternate.
Exactly half of the 24 finalists in F1C
Power maxed out, with seven making the
five-minute round. Going for 10 minutes in
an early-morning flyoff, only two-time
World Champ Randy Archer made the
max, despite the engine blowing at the end
of the run.
Ken Happersett was second at just two
seconds shy of 600 seconds on the flight.
John Warren got the third team spot, and
Dave Shirley is the alternate. MA