Steve “Surfi mp” Lange is a leader
and developer in ultralight
Slope Aerobatics fl ying. I had
the good fortune of fl ying with him at
the WeaselFest in April 2012 in Santa
Barbara, California, and saw some
fantastic maneuvers made possible by
a new breed of light and durable Slope
gliders, plus a great deal of pilot skill
honed by practice. Here is Steve’s guest
column on UltraBatics design and fl ight.
One of the most exciting new
developments in Slope Aerobatics—a
part of the hobby that’s made an
amazing comeback in recent years—has
been the development of ultralight
aerobatic gliders. These are fully
aerobatic designs constructed from
EPP foam with 1.5-meter to 2.5-meter
(60-inch to 100-inch) wingspans and
tremendously reduced fl ying weights
compared to older designs.
A typical 1.5-meter ultralight weighs
16 to 22 ounces ready to fl y—less than
half the usual weight for this type of design. With a wing loading in the 4 to 6 ounce
per-square-foot range, these airplanes fl y with full aerobatic performance in as little
as 6 to 8 mph winds at an average slope, and can take full advantage of any available
thermal lift.
These gliders use advanced airfoils with always-on dynamic camber changing
(provided via radio mixing) to give them identical performance, whether upright
or inverted. They also have effective rudders and enough
side area to perform knife-edge maneuvers, as well as slow
and point rolls. Some of the gliders employ radical full-fl ying
stabilizers and rudders capable of 180° rotation that allow
the airplane to fl ip around its CG, much like a jet with thrust
vectoring.
Their low weight, combined with EPP and laminating
fi lm construction, makes them nearly indestructible, even
more than a typical EPP airplane. By combining ultra
maneuverability with the low weight and durability, these
gliders let us fl y radical unlimited aerobatics almost anywhere,
in conditions under which a traditional aerobatics glider
couldn’t fl y.
While EPP construction and laminating fi lm covering are
well known in the Slope Soaring world, they previously were
used mainly in heavy-duty applications for combat wings
and dynamic soaring. The way they’ve been combined in
these ultralight aerobats is novel. They were pioneered in
Santa Barbara by Peter Richner. He’s been heavily involved
in RC fl ying since he was a child in Switzerland and has tremendous passion and
motivation to bring innovation to the hobby.
Drawing on his experience fl ying powered 3-D airplanes, and deeply inspired
by the Dream-Flight Alula, Peter tried to see if he could unlock new possibilities
for Slope Aerobatics by pursuing an ultralight wing loading. Using my Le Fish and
Spindrift designs as a basis for his work, he built a series of prototypes to successively
lower and lower weights, ultimately producing a Spindrift with a ready-to-fl y weight
of only 13.7 ounces—completely
unheard of for a 1.5-meter (60-inch)
EPP aerobatics glider!
Thanks to Peter’s innovation, I fi nally
realized my original vision for the Le
Fish—an aerobatics glider I designed
in 2005 with inspiration from the
French Slope Aerobatics scene. See the
“Sources” section for more information about the importance
of French inspiration in the resurrection of the American
Slope Aerobatics scene.
The primary goal of the Le Fish was a lively, fully aerobatic
three-axes (aileron/elevator/rudder) glider that could fly in the
same type of light lift as a Dream-Flight Weasel and withstand
the same kind of abuse. The Le Fish has become a commercial
success since its release in 2006, and is now flown throughout
the world.
The flying weight of Le Fish (built following traditional
methods), is roughly 38 to 42 ounces with a wing loading of
10 to 13 ounces per square foot. While this produces a fun,
durable, and capable glider, it can’t fly in light lift and requires
approximately 10 to 12 mph to come alive. Following Peter’s
techniques, I built a Le Fish to a flying weight of 16.5 ounces
and discovered, as Peter had, that a new world of aerobatic
performance was unlocked.
Not only could we now fly aerobatics in super light “Weasel”
lift, but we found that the low weight of the airplanes made
stalls gentle, allowing recovery in half of a fuselage length or
less. This allowed us to fly lower and with greater control.
Inverted fin and wingtip drags became easier to perform.
I found that by adding a Madslide-inspired full-flying
stabilizer with 180° rotation on my airplane, I was able to
perform radical flip maneuvers at eye level—just a few feet in
front of me—as I transferred from one mini-bowl in the slope
face to another. This was new, and this was fun!
I could finally enjoy the best of both worlds: a glider that
was as agile and light in the air as a Weasel or Alula (airplanes
that I’ve loved flying for years), but which had the added
capabilities that a fully aerobatic glider of conventional
planform provides. I found a new realm of creativity before me.
I could blast up out of one bowl, snap roll to inverted, and
drag my fin in the grass as I dropped into another bowl. We
could fly two airplanes at once within the bounds of a tiny
crevice barely 25 feet across, and treat it like a skateboard
half pipe—pumping up each side to keep our momentum
going and flying radical aerobatics nonstop, bouncing off of
each other’s airplanes with no damage and no crash when the
impacts occurred.
The durability of the glider meant that I could repeatedly
try tricks. The airplane simply soaked up abuse that, based on
previous experience, would have snapped tails and broken
fuselages had I done them with something heavier. I could fly
extremely close to myself, within inches of my face if I wanted,
with complete control and confidence. The overall experience
was liberating. It was everything I loved about flying a Weasel or
Alula, but taken to a new level of involvement and excitement.
The glider had become my brush, the slope face my canvas.
I was limited only by my imagination.
Videos of our flying quickly attracted the attention of the
worldwide Slope Aerobatics community, including being
featured on the homepages of Pierre Rondel’s Planet-
Soaring.com and Laurent Berlivet’s www.Jivaro-Models.org in France. The flying weights of our gliders elicited comments
and wonder, and we documented the construction techniques
in detail via the “How to Build a Swiss Fish” thread in
the Slope forum of www.RCGroups.com. By putting all
information in the public domain, including the plan for the
ultra-lightweight Le Fish on www.SlopeAerobatics.com, the
hope was that others would get involved and help push these
ideas forward. We didn’t have to wait long for that to happen!
One early innovation came from Dawson Henderson,
one of the best-known American Slope Aerobatics pilots.
He devised a pulley control system to address challenges
inherent to the Madslide-style 180° rotation elevator. Using
his own ultralightweight Le Fish, he was the first pilot to
successfully replicate the multiple flips shown in the original
Madslide video of Benoit Paysant-Le Roux (aka BPLR), the
French designer who invented this stabilizer arrangement
back in 2000 for his Madslide (see the “Sources” section for
more information). BPLR saw the videos and was impressed,
extending his congratulations to Dawson and encouraging us
in our efforts.
Pilots around the world began trying out their own
interpretations of our ultralight EPP aerobat philosophy.
In southern California, John Scahill collaborated with
Dan McCleary of Xtreme Gliders on a number of designs,
including a Power Scale Soaring (PSS) Extra with Madslidestyle
stabilizer and a neat Shark glider that looks like an actual
shark and does cool, flat spins.
Paige Anderson of Future Slope Designs also is marketing
the Flow, intending to exploit the capabilities of these
ultralight aerobats that perform virtually endless aerobatics
sequences. Leading Edge Gliders also offers ultralightweight
versions of the Le Fish and Spindrift designs that incorporate
all of these enhancements.
It’s been an exciting time, and the future is wide open. Peter
is already working on his next project, a 4-meter (160-inch)
ultralightweight aerobat that will surely make headlines as one
of the largest EPP aircraft ever flown.
I am looking for more ways to adapt my background in
skateboarding, surfing, and snowboarding to this type of
aerobatics. Dawson continues to inspire the world with his
smooth flying and beautiful videos that express the artistic
potential of what we’ve begun calling “Ultra-Batics.” These
ultralight aerobats have shown us that anything is possible, and
the only limitations are those which we place on ourselves.
Author’s Note
There’s no better or easier introduction to what ultralight
flying is about than a Dream-Flight Alula or Dream-Flight
Weasel. The lightweight philosophy they embody, and the
exciting style of highly aerobatic “in your face” flying they
encourage, is the core inspiration that has driven this journey
for Peter, Dawson, and me.
The ultralight three-axes aerobats extend the fun by offering
additional possibilities, but the Dream-Flight airplanes are a
perfect starting point. Because the Weasel and Alula airframes
are molded from EPO foam, you can have one in the air and
begin your exploration of close-in Slope Aerobatics with much
less time, effort, and cost than any other option.
Edition: Model Aviation - 2012/08
Page Numbers: 107,108,109
Edition: Model Aviation - 2012/08
Page Numbers: 107,108,109
Steve “Surfi mp” Lange is a leader
and developer in ultralight
Slope Aerobatics fl ying. I had
the good fortune of fl ying with him at
the WeaselFest in April 2012 in Santa
Barbara, California, and saw some
fantastic maneuvers made possible by
a new breed of light and durable Slope
gliders, plus a great deal of pilot skill
honed by practice. Here is Steve’s guest
column on UltraBatics design and fl ight.
One of the most exciting new
developments in Slope Aerobatics—a
part of the hobby that’s made an
amazing comeback in recent years—has
been the development of ultralight
aerobatic gliders. These are fully
aerobatic designs constructed from
EPP foam with 1.5-meter to 2.5-meter
(60-inch to 100-inch) wingspans and
tremendously reduced fl ying weights
compared to older designs.
A typical 1.5-meter ultralight weighs
16 to 22 ounces ready to fl y—less than
half the usual weight for this type of design. With a wing loading in the 4 to 6 ounce
per-square-foot range, these airplanes fl y with full aerobatic performance in as little
as 6 to 8 mph winds at an average slope, and can take full advantage of any available
thermal lift.
These gliders use advanced airfoils with always-on dynamic camber changing
(provided via radio mixing) to give them identical performance, whether upright
or inverted. They also have effective rudders and enough
side area to perform knife-edge maneuvers, as well as slow
and point rolls. Some of the gliders employ radical full-fl ying
stabilizers and rudders capable of 180° rotation that allow
the airplane to fl ip around its CG, much like a jet with thrust
vectoring.
Their low weight, combined with EPP and laminating
fi lm construction, makes them nearly indestructible, even
more than a typical EPP airplane. By combining ultra
maneuverability with the low weight and durability, these
gliders let us fl y radical unlimited aerobatics almost anywhere,
in conditions under which a traditional aerobatics glider
couldn’t fl y.
While EPP construction and laminating fi lm covering are
well known in the Slope Soaring world, they previously were
used mainly in heavy-duty applications for combat wings
and dynamic soaring. The way they’ve been combined in
these ultralight aerobats is novel. They were pioneered in
Santa Barbara by Peter Richner. He’s been heavily involved
in RC fl ying since he was a child in Switzerland and has tremendous passion and
motivation to bring innovation to the hobby.
Drawing on his experience fl ying powered 3-D airplanes, and deeply inspired
by the Dream-Flight Alula, Peter tried to see if he could unlock new possibilities
for Slope Aerobatics by pursuing an ultralight wing loading. Using my Le Fish and
Spindrift designs as a basis for his work, he built a series of prototypes to successively
lower and lower weights, ultimately producing a Spindrift with a ready-to-fl y weight
of only 13.7 ounces—completely
unheard of for a 1.5-meter (60-inch)
EPP aerobatics glider!
Thanks to Peter’s innovation, I fi nally
realized my original vision for the Le
Fish—an aerobatics glider I designed
in 2005 with inspiration from the
French Slope Aerobatics scene. See the
“Sources” section for more information about the importance
of French inspiration in the resurrection of the American
Slope Aerobatics scene.
The primary goal of the Le Fish was a lively, fully aerobatic
three-axes (aileron/elevator/rudder) glider that could fly in the
same type of light lift as a Dream-Flight Weasel and withstand
the same kind of abuse. The Le Fish has become a commercial
success since its release in 2006, and is now flown throughout
the world.
The flying weight of Le Fish (built following traditional
methods), is roughly 38 to 42 ounces with a wing loading of
10 to 13 ounces per square foot. While this produces a fun,
durable, and capable glider, it can’t fly in light lift and requires
approximately 10 to 12 mph to come alive. Following Peter’s
techniques, I built a Le Fish to a flying weight of 16.5 ounces
and discovered, as Peter had, that a new world of aerobatic
performance was unlocked.
Not only could we now fly aerobatics in super light “Weasel”
lift, but we found that the low weight of the airplanes made
stalls gentle, allowing recovery in half of a fuselage length or
less. This allowed us to fly lower and with greater control.
Inverted fin and wingtip drags became easier to perform.
I found that by adding a Madslide-inspired full-flying
stabilizer with 180° rotation on my airplane, I was able to
perform radical flip maneuvers at eye level—just a few feet in
front of me—as I transferred from one mini-bowl in the slope
face to another. This was new, and this was fun!
I could finally enjoy the best of both worlds: a glider that
was as agile and light in the air as a Weasel or Alula (airplanes
that I’ve loved flying for years), but which had the added
capabilities that a fully aerobatic glider of conventional
planform provides. I found a new realm of creativity before me.
I could blast up out of one bowl, snap roll to inverted, and
drag my fin in the grass as I dropped into another bowl. We
could fly two airplanes at once within the bounds of a tiny
crevice barely 25 feet across, and treat it like a skateboard
half pipe—pumping up each side to keep our momentum
going and flying radical aerobatics nonstop, bouncing off of
each other’s airplanes with no damage and no crash when the
impacts occurred.
The durability of the glider meant that I could repeatedly
try tricks. The airplane simply soaked up abuse that, based on
previous experience, would have snapped tails and broken
fuselages had I done them with something heavier. I could fly
extremely close to myself, within inches of my face if I wanted,
with complete control and confidence. The overall experience
was liberating. It was everything I loved about flying a Weasel or
Alula, but taken to a new level of involvement and excitement.
The glider had become my brush, the slope face my canvas.
I was limited only by my imagination.
Videos of our flying quickly attracted the attention of the
worldwide Slope Aerobatics community, including being
featured on the homepages of Pierre Rondel’s Planet-
Soaring.com and Laurent Berlivet’s www.Jivaro-Models.org in France. The flying weights of our gliders elicited comments
and wonder, and we documented the construction techniques
in detail via the “How to Build a Swiss Fish” thread in
the Slope forum of www.RCGroups.com. By putting all
information in the public domain, including the plan for the
ultra-lightweight Le Fish on www.SlopeAerobatics.com, the
hope was that others would get involved and help push these
ideas forward. We didn’t have to wait long for that to happen!
One early innovation came from Dawson Henderson,
one of the best-known American Slope Aerobatics pilots.
He devised a pulley control system to address challenges
inherent to the Madslide-style 180° rotation elevator. Using
his own ultralightweight Le Fish, he was the first pilot to
successfully replicate the multiple flips shown in the original
Madslide video of Benoit Paysant-Le Roux (aka BPLR), the
French designer who invented this stabilizer arrangement
back in 2000 for his Madslide (see the “Sources” section for
more information). BPLR saw the videos and was impressed,
extending his congratulations to Dawson and encouraging us
in our efforts.
Pilots around the world began trying out their own
interpretations of our ultralight EPP aerobat philosophy.
In southern California, John Scahill collaborated with
Dan McCleary of Xtreme Gliders on a number of designs,
including a Power Scale Soaring (PSS) Extra with Madslidestyle
stabilizer and a neat Shark glider that looks like an actual
shark and does cool, flat spins.
Paige Anderson of Future Slope Designs also is marketing
the Flow, intending to exploit the capabilities of these
ultralight aerobats that perform virtually endless aerobatics
sequences. Leading Edge Gliders also offers ultralightweight
versions of the Le Fish and Spindrift designs that incorporate
all of these enhancements.
It’s been an exciting time, and the future is wide open. Peter
is already working on his next project, a 4-meter (160-inch)
ultralightweight aerobat that will surely make headlines as one
of the largest EPP aircraft ever flown.
I am looking for more ways to adapt my background in
skateboarding, surfing, and snowboarding to this type of
aerobatics. Dawson continues to inspire the world with his
smooth flying and beautiful videos that express the artistic
potential of what we’ve begun calling “Ultra-Batics.” These
ultralight aerobats have shown us that anything is possible, and
the only limitations are those which we place on ourselves.
Author’s Note
There’s no better or easier introduction to what ultralight
flying is about than a Dream-Flight Alula or Dream-Flight
Weasel. The lightweight philosophy they embody, and the
exciting style of highly aerobatic “in your face” flying they
encourage, is the core inspiration that has driven this journey
for Peter, Dawson, and me.
The ultralight three-axes aerobats extend the fun by offering
additional possibilities, but the Dream-Flight airplanes are a
perfect starting point. Because the Weasel and Alula airframes
are molded from EPO foam, you can have one in the air and
begin your exploration of close-in Slope Aerobatics with much
less time, effort, and cost than any other option.
Edition: Model Aviation - 2012/08
Page Numbers: 107,108,109
Steve “Surfi mp” Lange is a leader
and developer in ultralight
Slope Aerobatics fl ying. I had
the good fortune of fl ying with him at
the WeaselFest in April 2012 in Santa
Barbara, California, and saw some
fantastic maneuvers made possible by
a new breed of light and durable Slope
gliders, plus a great deal of pilot skill
honed by practice. Here is Steve’s guest
column on UltraBatics design and fl ight.
One of the most exciting new
developments in Slope Aerobatics—a
part of the hobby that’s made an
amazing comeback in recent years—has
been the development of ultralight
aerobatic gliders. These are fully
aerobatic designs constructed from
EPP foam with 1.5-meter to 2.5-meter
(60-inch to 100-inch) wingspans and
tremendously reduced fl ying weights
compared to older designs.
A typical 1.5-meter ultralight weighs
16 to 22 ounces ready to fl y—less than
half the usual weight for this type of design. With a wing loading in the 4 to 6 ounce
per-square-foot range, these airplanes fl y with full aerobatic performance in as little
as 6 to 8 mph winds at an average slope, and can take full advantage of any available
thermal lift.
These gliders use advanced airfoils with always-on dynamic camber changing
(provided via radio mixing) to give them identical performance, whether upright
or inverted. They also have effective rudders and enough
side area to perform knife-edge maneuvers, as well as slow
and point rolls. Some of the gliders employ radical full-fl ying
stabilizers and rudders capable of 180° rotation that allow
the airplane to fl ip around its CG, much like a jet with thrust
vectoring.
Their low weight, combined with EPP and laminating
fi lm construction, makes them nearly indestructible, even
more than a typical EPP airplane. By combining ultra
maneuverability with the low weight and durability, these
gliders let us fl y radical unlimited aerobatics almost anywhere,
in conditions under which a traditional aerobatics glider
couldn’t fl y.
While EPP construction and laminating fi lm covering are
well known in the Slope Soaring world, they previously were
used mainly in heavy-duty applications for combat wings
and dynamic soaring. The way they’ve been combined in
these ultralight aerobats is novel. They were pioneered in
Santa Barbara by Peter Richner. He’s been heavily involved
in RC fl ying since he was a child in Switzerland and has tremendous passion and
motivation to bring innovation to the hobby.
Drawing on his experience fl ying powered 3-D airplanes, and deeply inspired
by the Dream-Flight Alula, Peter tried to see if he could unlock new possibilities
for Slope Aerobatics by pursuing an ultralight wing loading. Using my Le Fish and
Spindrift designs as a basis for his work, he built a series of prototypes to successively
lower and lower weights, ultimately producing a Spindrift with a ready-to-fl y weight
of only 13.7 ounces—completely
unheard of for a 1.5-meter (60-inch)
EPP aerobatics glider!
Thanks to Peter’s innovation, I fi nally
realized my original vision for the Le
Fish—an aerobatics glider I designed
in 2005 with inspiration from the
French Slope Aerobatics scene. See the
“Sources” section for more information about the importance
of French inspiration in the resurrection of the American
Slope Aerobatics scene.
The primary goal of the Le Fish was a lively, fully aerobatic
three-axes (aileron/elevator/rudder) glider that could fly in the
same type of light lift as a Dream-Flight Weasel and withstand
the same kind of abuse. The Le Fish has become a commercial
success since its release in 2006, and is now flown throughout
the world.
The flying weight of Le Fish (built following traditional
methods), is roughly 38 to 42 ounces with a wing loading of
10 to 13 ounces per square foot. While this produces a fun,
durable, and capable glider, it can’t fly in light lift and requires
approximately 10 to 12 mph to come alive. Following Peter’s
techniques, I built a Le Fish to a flying weight of 16.5 ounces
and discovered, as Peter had, that a new world of aerobatic
performance was unlocked.
Not only could we now fly aerobatics in super light “Weasel”
lift, but we found that the low weight of the airplanes made
stalls gentle, allowing recovery in half of a fuselage length or
less. This allowed us to fly lower and with greater control.
Inverted fin and wingtip drags became easier to perform.
I found that by adding a Madslide-inspired full-flying
stabilizer with 180° rotation on my airplane, I was able to
perform radical flip maneuvers at eye level—just a few feet in
front of me—as I transferred from one mini-bowl in the slope
face to another. This was new, and this was fun!
I could finally enjoy the best of both worlds: a glider that
was as agile and light in the air as a Weasel or Alula (airplanes
that I’ve loved flying for years), but which had the added
capabilities that a fully aerobatic glider of conventional
planform provides. I found a new realm of creativity before me.
I could blast up out of one bowl, snap roll to inverted, and
drag my fin in the grass as I dropped into another bowl. We
could fly two airplanes at once within the bounds of a tiny
crevice barely 25 feet across, and treat it like a skateboard
half pipe—pumping up each side to keep our momentum
going and flying radical aerobatics nonstop, bouncing off of
each other’s airplanes with no damage and no crash when the
impacts occurred.
The durability of the glider meant that I could repeatedly
try tricks. The airplane simply soaked up abuse that, based on
previous experience, would have snapped tails and broken
fuselages had I done them with something heavier. I could fly
extremely close to myself, within inches of my face if I wanted,
with complete control and confidence. The overall experience
was liberating. It was everything I loved about flying a Weasel or
Alula, but taken to a new level of involvement and excitement.
The glider had become my brush, the slope face my canvas.
I was limited only by my imagination.
Videos of our flying quickly attracted the attention of the
worldwide Slope Aerobatics community, including being
featured on the homepages of Pierre Rondel’s Planet-
Soaring.com and Laurent Berlivet’s www.Jivaro-Models.org in France. The flying weights of our gliders elicited comments
and wonder, and we documented the construction techniques
in detail via the “How to Build a Swiss Fish” thread in
the Slope forum of www.RCGroups.com. By putting all
information in the public domain, including the plan for the
ultra-lightweight Le Fish on www.SlopeAerobatics.com, the
hope was that others would get involved and help push these
ideas forward. We didn’t have to wait long for that to happen!
One early innovation came from Dawson Henderson,
one of the best-known American Slope Aerobatics pilots.
He devised a pulley control system to address challenges
inherent to the Madslide-style 180° rotation elevator. Using
his own ultralightweight Le Fish, he was the first pilot to
successfully replicate the multiple flips shown in the original
Madslide video of Benoit Paysant-Le Roux (aka BPLR), the
French designer who invented this stabilizer arrangement
back in 2000 for his Madslide (see the “Sources” section for
more information). BPLR saw the videos and was impressed,
extending his congratulations to Dawson and encouraging us
in our efforts.
Pilots around the world began trying out their own
interpretations of our ultralight EPP aerobat philosophy.
In southern California, John Scahill collaborated with
Dan McCleary of Xtreme Gliders on a number of designs,
including a Power Scale Soaring (PSS) Extra with Madslidestyle
stabilizer and a neat Shark glider that looks like an actual
shark and does cool, flat spins.
Paige Anderson of Future Slope Designs also is marketing
the Flow, intending to exploit the capabilities of these
ultralight aerobats that perform virtually endless aerobatics
sequences. Leading Edge Gliders also offers ultralightweight
versions of the Le Fish and Spindrift designs that incorporate
all of these enhancements.
It’s been an exciting time, and the future is wide open. Peter
is already working on his next project, a 4-meter (160-inch)
ultralightweight aerobat that will surely make headlines as one
of the largest EPP aircraft ever flown.
I am looking for more ways to adapt my background in
skateboarding, surfing, and snowboarding to this type of
aerobatics. Dawson continues to inspire the world with his
smooth flying and beautiful videos that express the artistic
potential of what we’ve begun calling “Ultra-Batics.” These
ultralight aerobats have shown us that anything is possible, and
the only limitations are those which we place on ourselves.
Author’s Note
There’s no better or easier introduction to what ultralight
flying is about than a Dream-Flight Alula or Dream-Flight
Weasel. The lightweight philosophy they embody, and the
exciting style of highly aerobatic “in your face” flying they
encourage, is the core inspiration that has driven this journey
for Peter, Dawson, and me.
The ultralight three-axes aerobats extend the fun by offering
additional possibilities, but the Dream-Flight airplanes are a
perfect starting point. Because the Weasel and Alula airframes
are molded from EPO foam, you can have one in the air and
begin your exploration of close-in Slope Aerobatics with much
less time, effort, and cost than any other option.
