52/1 Performance in a 15M ship at half the weight.

[SF]

I wrote the following article and submitted it to Soaring for
publication because it was something I was interested in and I thought
others would be too. It was rejected because the subject matter
wasn't suitable for soaring. Greg Cole is doing something
extraordinary at Windward Performance and I feel that Soaring is doing
all of us a disservice by not putting content like this in the
magazine.
******************
My Trip To Windward Performance

At the 2008 SSA convention in Albuquerque, NM I attended Greg Cole’s
presentation on the new 15M sailplane he’s building called the
DuckHawk. The presentation piqued my interest and I managed to
retain the knowledge that the DuckHawk is an American name for
Peregrine Falcon, the fastest moving creature on earth, and that Greg
Cole’s Sailplane factory is in Bend Oregon.

Other details stuck with me too, like an L/D of 52/1. Minimum Sink
is 111 fpm; empty weight is 300 Lbs, and this Hawk has an aspect ratio
of 30.0:1. The 200 Kt. VNE would make for one hot smoking final
glide.

When business took me to Portland, Oregon last Fall, I realized I’d be
fairly close to Bend. A few phone calls got me an appointment with
Greg Cole, president and creative force behind Windward Performance
Ltd, DuckHawk’s creator as well as builders of 11M span SparrowHawk.

Greg Cole has been building and flying his designs since he was a
kid. He has a BSME from the University of North Dakota, and a MSAE
from Notre Dame. He holds a US patent on propeller design. His work
experience includes the McCauley Propeller Company, Columbia Aircraft
Company (chief Engineer), Cirrus Design, Lancair, and Adam Aircraft.
He has made significant Design contributions to several different
aircraft including: the Lancair Legacy, the Lancair Evolution, The
Columbia 300, The Chanute, The A500, and of course the SparrowHawk
which is the only U.S. designed sailplane to hold a world record in 30
years. The Columbia 300 bears mentioning again as it was the first
new design certified by the FAA in 17 years, and it was a full
composite airframe from a new company.

For those of us that live in America’s South, the drive from Portland
to Bend is simply amazing. In South Carolina we drive in one green
tunnel of pine trees after another, and while we have mountains, they
don’t have snow on them in early September like Mount Hood. The drive
down through the high desert is truly beautiful - just don’t try to
pump your own gas. Oregon gas stations are required by state law to be
full service.

The modern sailplane is one truly amazing piece of machinery. They
may look simple but they’re among the most sophisticated aircraft
flying. I learned to fly in a Grob 103. My first single-place glider
was a 1968 Open Cirrus with massive fiberglass spars, fat wings, and
heavy enough to send everyone on the field running the other direction
any time you pull your trailer into the assembly area.

I moved up to a mid-80’s LS6-a, and began teaching students in a
2-33. The historical progression from the 2-33 and its flying barn
door performance, to a first generation glass ship like the Cirrus, a
second generation glass ship like the LS6-a, and a modern glider using
knife like laminar-flow wings is exciting to experience firsthand.
One of my friends sums it up saying “these new planes just do what you
want them to do so much easier, and they do it so much better”.

Improvements in modern sailplane performance have been driven by
advances in materials, a better understanding of how to design
aerodynamic structures with these materials, computer modeling, and
leaps in understanding aerodynamic principles. Most modern sailplanes,
with the exception of Windward Performance’s aircraft, are built with
a wet, room temperature cured, epoxy resin lay up using glass, carbon,
or Kevlar fiber reinforcement. The reinforcing cloth is laid into the
mold by hand and the epoxy squeegeed, or painted on. This type of
construction process was quite an advance over previous wood and metal
construction and quite a bit better than “fiberglass” or polyester
resins or even the vinyl ester resins but still imposes several
limitations on how strong aircraft parts may be made.

When the resins cure at room temperature there is fairly short
amount of “out-time” – the number of minutes workers have to craft the
part before the resin’s curing process begins. Complicated multi-
layer layups have to be done quickly. Yet fiber orientation and
wetout are important in critical aircraft applications. As a result
room-temperature resin application often means a heavier composite
structure to maintain structural safety. The room temperature curing
of resins, causes the finished part to lose structural integrity
rapidly at temperatures over 140 F, which is why modern composite
sailplanes are painted white. If they were painted black or even red
they would heat up under sunlight and loose structural integrity.

Thus Cole’s Windward Performance is the only sailplane manufacturer
I’m aware of to use sophisticated prepreg oven-cured carbon fiber
construction. Prepreg carbon fiber is produced in a factory by
sandwiching a carbon fiber cloth between two epoxy resin sheets, the
sandwich is then run this between high-pressure rollers. The high
pressure insures an even and complete epoxy coating of the fabric with
the ability to very precisely control the ratio of resin to fabric.
This allows the composite’s weight to remain low but optimized for
strength with very tight tolerances. Once the fabric is epoxy coated
it is refrigerated for storage and transport, greatly retarding the
start of the curing process.

Since the resin does not cure at room temperatures there is much more
out-time in which to lay up the prepreg material in, say, a wing-mold
while avoiding mistakes from rushing. There’ more time for forming
complicated multi-layer configurations.

In Windward’s aircraft, the prepreg layup is vacuum-bagged to ensure
all air is squeezed out of the layup and the entire assembly goes into
an oven to cure at high temperatures. The benefits of all this are
lighter, far stronger and stiffer composites with a much larger
temperature operating range than conventional wet layup composites
afford.
Given these advantages, and given Greg Cole’s expertise and obviously
high standards of craftsmanship, it became clear why Windward
Performance uses prepregs, and why they result in the Duck Hawk’s
performance advantages.

A winning 15M racing sailplane moves around the course in the least
amount of time with the highest average cross country speed. The key
to obtaining that is, naturally, minimizing the time you go slow.
Climbing well and going fast between thermals sounds easy, but
mastering this simple concept is far from easy. Most of us with
modest skills in this area could use all the help we can get from the
aircraft.

The modeling of average cross country speeds with different
atmospheric conditions allowed performance simulations of different
design iterations to be run and small improvements or losses to be
determined. The accuracy of modeling new designs was, for Cole,
validated by modeling current designs with known performance
characteristics.

Designs that can be made light with small wing areas offer improved
performance over conventional designs especially in tough conditions.
Tough conditions – small thermals, weak lift, headwinds, etc. - seem
to have a far greater negative impact on my contest results than do
the positives of favorable conditions.

Cole’s calculations show soaring with the ability to fly well with low
lift coefficients can also give the ability to go fast at relatively
low wing loadings, meaning faster average cross country speeds. The
results of the modeling process indicated an optimum with a wing area
of 80 SQFT, and a wing loading of 8.75 LBS/SQFT.

Determining the optimum airfoil also benefits from Cole’s computer
modeling process. Structural constraints start as the wing area drops
below 90 square feet, and wing volume available for ballast drops
rapidly as well. As wing area decreases, the Reynolds number goes
down and achieving low drag at high and low lift coefficients becomes
more and more difficult.

Good stalling behavior is another factor Cole considered. Amongst all
of the airfoils designed the final airfoil selected for the DuckHawk
is the CS33-18; it allows the aircraft to fly at low lift coefficients
at high speeds as well as at high lift coefficients at low speeds.
Winglets were considered but an evaluation of their negatives and
benefits indicated the DuckHawk would fly better without them when
real world soaring techniques were considered.

State of the art performance is what Cole is after here, plus safety
and relative affordability. The 30:1 aspect ratio and its razor thin
wings are an obvious clue this is not your generic modern glider.
Eighty-pound wings will be appreciated by everyone during assembly.
Eighteen-meter L/D performance with a 15-meter wing span will result
in lower drag while circling and this plane should climb like a
bandit.

The ship’s lower mass will give it an induced drag advantage of 29%
compared to today’s 15m sailplanes at equivalent wing loadings. That
means better climbing. Lower wetted area means lower parasitic drag
and improved high speed running. A wing loading range between 6.25 and
10.0 lbs./sq. Ft. will give it ability to adapt to a wide variety of
soaring conditions - a plane that will get you quickly around the
course on the tough days and fly faster than anything else out there
now on really good days.

Before my trip to Windward Performance I was unaware of the complexity
of the sailplane manufacturing process. The plugs and molds required
to produce a sailplane, fill a good sized warehouse even without
working room around them. The design and production capabilities of
this small sailplane operation were a very pleasant surprise. This is
a small operation but it possesses world class design talent and state
of the art manufacturing processes. While I love my German sailplane
and fully recognize the abilities of the established sailplane
manufacturing companies, I find myself rooting for the underdog home
team in this case.

The first DuckHawk should take to the air summer 2009, and I look
forward to seeing the finished product. In addition to the DuckHawk
Windward has a few other products currently in the works. They are
currently building the Perlan sailplane designed to take two people to
90,000 FT. The Windward Goshawk, an electric aircraft is also being
built. Advances in composites are ushering in a new era in aircraft
innovation and thanks to Greg Cole’s love of soaring we get be benefit
from his creativity, with an exciting new American sailplane.

[Greg Arnold[_2_]]

SF wrote:
> I wrote the following article and submitted it to Soaring for
> publication because it was something I was interested in and I thought
> others would be too. It was rejected because the subject matter
> wasn't suitable for soaring. Greg Cole is doing something
> extraordinary at Windward Performance and I feel that Soaring is doing
> all of us a disservice by not putting content like this in the
> magazine.


Send it to John Roake at Gliding International in NZ, which unlike
SOARING is edited by a gliding enthusiast.


> ******************
> My Trip To Windward Performance
>
> At the 2008 SSA convention in Albuquerque, NM I attended Greg Cole’s
> presentation on the new 15M sailplane he’s building called the
> DuckHawk. The presentation piqued my interest and I managed to
> retain the knowledge that the DuckHawk is an American name for
> Peregrine Falcon, the fastest moving creature on earth, and that Greg
> Cole’s Sailplane factory is in Bend Oregon.
>
> Other details stuck with me too, like an L/D of 52/1. Minimum Sink
> is 111 fpm; empty weight is 300 Lbs, and this Hawk has an aspect ratio
> of 30.0:1. The 200 Kt. VNE would make for one hot smoking final
> glide.
>
> When business took me to Portland, Oregon last Fall, I realized I’d be
> fairly close to Bend. A few phone calls got me an appointment with
> Greg Cole, president and creative force behind Windward Performance
> Ltd, DuckHawk’s creator as well as builders of 11M span SparrowHawk.
>
> Greg Cole has been building and flying his designs since he was a
> kid. He has a BSME from the University of North Dakota, and a MSAE
> from Notre Dame. He holds a US patent on propeller design. His work
> experience includes the McCauley Propeller Company, Columbia Aircraft
> Company (chief Engineer), Cirrus Design, Lancair, and Adam Aircraft.
> He has made significant Design contributions to several different
> aircraft including: the Lancair Legacy, the Lancair Evolution, The
> Columbia 300, The Chanute, The A500, and of course the SparrowHawk
> which is the only U.S. designed sailplane to hold a world record in 30
> years. The Columbia 300 bears mentioning again as it was the first
> new design certified by the FAA in 17 years, and it was a full
> composite airframe from a new company.
>
> For those of us that live in America’s South, the drive from Portland
> to Bend is simply amazing. In South Carolina we drive in one green
> tunnel of pine trees after another, and while we have mountains, they
> don’t have snow on them in early September like Mount Hood. The drive
> down through the high desert is truly beautiful - just don’t try to
> pump your own gas. Oregon gas stations are required by state law to be
> full service.
>
> The modern sailplane is one truly amazing piece of machinery. They
> may look simple but they’re among the most sophisticated aircraft
> flying. I learned to fly in a Grob 103. My first single-place glider
> was a 1968 Open Cirrus with massive fiberglass spars, fat wings, and
> heavy enough to send everyone on the field running the other direction
> any time you pull your trailer into the assembly area.
>
> I moved up to a mid-80’s LS6-a, and began teaching students in a
> 2-33. The historical progression from the 2-33 and its flying barn
> door performance, to a first generation glass ship like the Cirrus, a
> second generation glass ship like the LS6-a, and a modern glider using
> knife like laminar-flow wings is exciting to experience firsthand.
> One of my friends sums it up saying “these new planes just do what you
> want them to do so much easier, and they do it so much better”.
>
> Improvements in modern sailplane performance have been driven by
> advances in materials, a better understanding of how to design
> aerodynamic structures with these materials, computer modeling, and
> leaps in understanding aerodynamic principles. Most modern sailplanes,
> with the exception of Windward Performance’s aircraft, are built with
> a wet, room temperature cured, epoxy resin lay up using glass, carbon,
> or Kevlar fiber reinforcement. The reinforcing cloth is laid into the
> mold by hand and the epoxy squeegeed, or painted on. This type of
> construction process was quite an advance over previous wood and metal
> construction and quite a bit better than “fiberglass” or polyester
> resins or even the vinyl ester resins but still imposes several
> limitations on how strong aircraft parts may be made.
>
> When the resins cure at room temperature there is fairly short
> amount of “out-time” – the number of minutes workers have to craft the
> part before the resin’s curing process begins. Complicated multi-
> layer layups have to be done quickly. Yet fiber orientation and
> wetout are important in critical aircraft applications. As a result
> room-temperature resin application often means a heavier composite
> structure to maintain structural safety. The room temperature curing
> of resins, causes the finished part to lose structural integrity
> rapidly at temperatures over 140 F, which is why modern composite
> sailplanes are painted white. If they were painted black or even red
> they would heat up under sunlight and loose structural integrity.
>
> Thus Cole’s Windward Performance is the only sailplane manufacturer
> I’m aware of to use sophisticated prepreg oven-cured carbon fiber
> construction. Prepreg carbon fiber is produced in a factory by
> sandwiching a carbon fiber cloth between two epoxy resin sheets, the
> sandwich is then run this between high-pressure rollers. The high
> pressure insures an even and complete epoxy coating of the fabric with
> the ability to very precisely control the ratio of resin to fabric.
> This allows the composite’s weight to remain low but optimized for
> strength with very tight tolerances. Once the fabric is epoxy coated
> it is refrigerated for storage and transport, greatly retarding the
> start of the curing process.
>
> Since the resin does not cure at room temperatures there is much more
> out-time in which to lay up the prepreg material in, say, a wing-mold
> while avoiding mistakes from rushing. There’ more time for forming
> complicated multi-layer configurations.
>
> In Windward’s aircraft, the prepreg layup is vacuum-bagged to ensure
> all air is squeezed out of the layup and the entire assembly goes into
> an oven to cure at high temperatures. The benefits of all this are
> lighter, far stronger and stiffer composites with a much larger
> temperature operating range than conventional wet layup composites
> afford.
> Given these advantages, and given Greg Cole’s expertise and obviously
> high standards of craftsmanship, it became clear why Windward
> Performance uses prepregs, and why they result in the Duck Hawk’s
> performance advantages.
>
> A winning 15M racing sailplane moves around the course in the least
> amount of time with the highest average cross country speed. The key
> to obtaining that is, naturally, minimizing the time you go slow.
> Climbing well and going fast between thermals sounds easy, but
> mastering this simple concept is far from easy. Most of us with
> modest skills in this area could use all the help we can get from the
> aircraft.
>
> The modeling of average cross country speeds with different
> atmospheric conditions allowed performance simulations of different
> design iterations to be run and small improvements or losses to be
> determined. The accuracy of modeling new designs was, for Cole,
> validated by modeling current designs with known performance
> characteristics.
>
> Designs that can be made light with small wing areas offer improved
> performance over conventional designs especially in tough conditions.
> Tough conditions – small thermals, weak lift, headwinds, etc. - seem
> to have a far greater negative impact on my contest results than do
> the positives of favorable conditions.
>
> Cole’s calculations show soaring with the ability to fly well with low
> lift coefficients can also give the ability to go fast at relatively
> low wing loadings, meaning faster average cross country speeds. The
> results of the modeling process indicated an optimum with a wing area
> of 80 SQFT, and a wing loading of 8.75 LBS/SQFT.
>
> Determining the optimum airfoil also benefits from Cole’s computer
> modeling process. Structural constraints start as the wing area drops
> below 90 square feet, and wing volume available for ballast drops
> rapidly as well. As wing area decreases, the Reynolds number goes
> down and achieving low drag at high and low lift coefficients becomes
> more and more difficult.
>
> Good stalling behavior is another factor Cole considered. Amongst all
> of the airfoils designed the final airfoil selected for the DuckHawk
> is the CS33-18; it allows the aircraft to fly at low lift coefficients
> at high speeds as well as at high lift coefficients at low speeds.
> Winglets were considered but an evaluation of their negatives and
> benefits indicated the DuckHawk would fly better without them when
> real world soaring techniques were considered.
>
> State of the art performance is what Cole is after here, plus safety
> and relative affordability. The 30:1 aspect ratio and its razor thin
> wings are an obvious clue this is not your generic modern glider.
> Eighty-pound wings will be appreciated by everyone during assembly.
> Eighteen-meter L/D performance with a 15-meter wing span will result
> in lower drag while circling and this plane should climb like a
> bandit.
>
> The ship’s lower mass will give it an induced drag advantage of 29%
> compared to today’s 15m sailplanes at equivalent wing loadings. That
> means better climbing. Lower wetted area means lower parasitic drag
> and improved high speed running. A wing loading range between 6.25 and
> 10.0 lbs./sq. Ft. will give it ability to adapt to a wide variety of
> soaring conditions - a plane that will get you quickly around the
> course on the tough days and fly faster than anything else out there
> now on really good days.
>
> Before my trip to Windward Performance I was unaware of the complexity
> of the sailplane manufacturing process. The plugs and molds required
> to produce a sailplane, fill a good sized warehouse even without
> working room around them. The design and production capabilities of
> this small sailplane operation were a very pleasant surprise. This is
> a small operation but it possesses world class design talent and state
> of the art manufacturing processes. While I love my German sailplane
> and fully recognize the abilities of the established sailplane
> manufacturing companies, I find myself rooting for the underdog home
> team in this case.
>
> The first DuckHawk should take to the air summer 2009, and I look
> forward to seeing the finished product. In addition to the DuckHawk
> Windward has a few other products currently in the works. They are
> currently building the Perlan sailplane designed to take two people to
> 90,000 FT. The Windward Goshawk, an electric aircraft is also being
> built. Advances in composites are ushering in a new era in aircraft
> innovation and thanks to Greg Cole’s love of soaring we get be benefit
> from his creativity, with an exciting new American sailplane.

[Brad[_2_]]

On Feb 25, 6:08*pm, Greg Arnold > wrote:
> SF wrote:
> > I wrote the following article and submitted it to Soaring for
> > publication because it was something I was interested in and I thought
> > others would be too. *It was rejected because the subject matter
> > wasn't suitable for soaring. *Greg Cole is doing something
> > extraordinary at Windward Performance and I feel that Soaring is doing
> > all of us a disservice by not putting content like this in the
> > magazine.
>
> Send it to John Roake at Gliding International in NZ, which unlike
> SOARING is edited by a gliding enthusiast.
>
>
>
> > ******************
> > My Trip To Windward Performance
>
> > At the 2008 SSA convention in Albuquerque, NM I attended Greg Cole’s
> > presentation on the new 15M sailplane he’s building called the
> > DuckHawk. * The presentation piqued my interest and I managed to
> > retain the knowledge that the DuckHawk is an American name for
> > Peregrine Falcon, the fastest moving creature on earth, and that Greg
> > Cole’s Sailplane factory is in Bend Oregon.
>
> > * *Other details stuck with me too, like an L/D of 52/1. *Minimum Sink
> > is 111 fpm; empty weight is 300 Lbs, and this Hawk has an aspect ratio
> > of 30.0:1. *The 200 Kt. VNE would make for one hot smoking final
> > glide.
>
> > When business took me to Portland, Oregon last Fall, I realized I’d be
> > fairly close to Bend. A few phone calls got me an appointment with
> > Greg Cole, president and creative force behind Windward Performance
> > Ltd, DuckHawk’s creator as well as builders of 11M span SparrowHawk.
>
> > Greg Cole has been building and flying his designs since he was a
> > kid. *He has a BSME from the University of North Dakota, and a MSAE
> > from Notre Dame. *He holds a US patent on propeller design. *His work
> > experience includes the McCauley Propeller Company, Columbia Aircraft
> > Company (chief Engineer), Cirrus Design, Lancair, and Adam Aircraft.
> > He has made significant Design contributions to several different
> > aircraft including: the Lancair Legacy, the Lancair Evolution, The
> > Columbia 300, The Chanute, The A500, and of course the SparrowHawk
> > which is the only U.S. designed sailplane to hold a world record in 30
> > years. *The Columbia 300 bears mentioning again as it was the first
> > new design certified by the FAA in 17 years, and it was a full
> > composite airframe from a new company.
>
> > For those of us that live in America’s South, the drive from Portland
> > to Bend is simply amazing. * In South Carolina we drive in one green
> > tunnel of pine trees after another, and while we have mountains, they
> > don’t have snow on them in early September like Mount Hood. *The drive
> > down through the high desert is truly beautiful - just don’t try to
> > pump your own gas. Oregon gas stations are required by state law to be
> > full service.
>
> > The modern sailplane is one truly amazing piece of machinery. *They
> > may look simple but they’re among the most sophisticated aircraft
> > flying. *I learned to fly in a Grob 103. *My first single-place glider
> > was a 1968 Open Cirrus with massive fiberglass spars, fat wings, and
> > heavy enough to send everyone on the field running the other direction
> > any time you pull your trailer into the assembly area.
>
> > I moved up to a mid-80’s LS6-a, and began teaching students in a
> > 2-33. *The historical progression from the 2-33 and its flying barn
> > door performance, to a first generation glass ship like the Cirrus, a
> > second generation glass ship like the LS6-a, and a modern glider using
> > knife like laminar-flow wings is exciting to experience firsthand.
> > One of my friends sums it up saying “these new planes just do what you
> > want them to do so much easier, and they do it so much better”.
>
> > Improvements in modern sailplane performance have been driven by
> > advances in materials, a better understanding of how to design
> > aerodynamic structures with these materials, computer modeling, and
> > leaps in understanding aerodynamic principles. Most modern sailplanes,
> > with the exception of Windward Performance’s aircraft, are built with
> > a wet, room temperature cured, epoxy resin lay up using glass, carbon,
> > or Kevlar fiber reinforcement. *The reinforcing cloth is laid into the
> > mold by hand and the epoxy squeegeed, or painted on. *This type of
> > construction process was quite an advance over previous wood and metal
> > construction and quite a bit better than “fiberglass” or polyester
> > resins or even the vinyl ester resins but still imposes several
> > limitations on how strong aircraft parts may be made.
>
> > * When the resins cure at room temperature there is fairly short
> > amount of “out-time” – the number of minutes workers have to craft the
> > part before the resin’s curing process begins. *Complicated multi-
> > layer layups have to be done quickly. *Yet fiber orientation and
> > wetout are important in critical aircraft applications. As a result
> > room-temperature resin application often means a heavier composite
> > structure to maintain structural safety. *The room temperature curing
> > of resins, causes the finished part to lose structural integrity
> > rapidly at temperatures over 140 F, which is why modern composite
> > sailplanes are painted white. *If they were painted black or even red
> > they would heat up under sunlight and loose structural integrity.
>
> > Thus Cole’s Windward Performance is the only sailplane manufacturer
> > I’m aware of to use sophisticated prepreg oven-cured carbon fiber
> > construction. *Prepreg carbon fiber is produced in a factory by
> > sandwiching a carbon fiber cloth between two epoxy resin sheets, the
> > sandwich is then run this between high-pressure rollers. *The high
> > pressure insures an even and complete epoxy coating of the fabric with
> > the ability to very precisely control the ratio of resin to fabric.
> > This allows the composite’s weight to remain low but optimized for
> > strength with very tight tolerances. *Once the fabric is epoxy coated
> > it is refrigerated for storage and transport, greatly retarding the
> > start of the curing process.
>
> > Since the resin does not cure at room temperatures there is much more
> > out-time in which to lay up the prepreg material in, say, a wing-mold
> > while avoiding mistakes from rushing. There’ more time for forming
> > complicated multi-layer configurations.
>
> > In Windward’s aircraft, the prepreg layup is vacuum-bagged to ensure
> > all air is squeezed out of the layup and the entire assembly goes into
> > an oven to cure at high temperatures. The benefits of all this are
> > lighter, far stronger and stiffer composites with a much larger
> > temperature operating range than conventional wet layup composites
> > afford.
> > Given these advantages, and given Greg Cole’s expertise and obviously
> > high standards of craftsmanship, it became clear why Windward
> > Performance uses prepregs, and why they result in the Duck Hawk’s
> > performance advantages.
>
> > A winning 15M racing sailplane moves around the course in the least
> > amount of time with the highest average cross country speed. *The key
> > to obtaining that is, naturally, minimizing the time you go slow.
> > Climbing well and going fast between thermals sounds easy, but
> > mastering this simple concept is far from easy. *Most of us with
> > modest skills in this area could use all the help we can get from the
> > aircraft.
>
> > The modeling of average cross country speeds with different
> > atmospheric conditions allowed performance simulations of different
> > design iterations to be run and small improvements or losses to be
> > determined. *The accuracy of modeling new designs was, for Cole,
> > validated by modeling current designs with known performance
> > characteristics.
>
> > Designs that can be made light with small wing areas offer improved
> > performance over conventional designs especially in tough conditions.
> > Tough conditions – small thermals, weak lift, headwinds, etc. - seem
> > to have a far greater negative impact on my contest results than do
> > the positives of favorable conditions.
>
> > Cole’s calculations show soaring with the ability to fly well with low
> > lift coefficients can also give the ability to go fast at relatively
> > low wing loadings, meaning faster average cross country speeds. *The
> > results of the modeling process indicated an optimum with a wing area
> > of 80 SQFT, and a wing loading of 8.75 LBS/SQFT.
>
> > Determining the optimum airfoil also benefits from Cole’s computer
> > modeling process. *Structural constraints start as the wing area drops
> > below 90 square feet, and wing volume available for ballast drops
> > rapidly as well. *As wing area decreases, the Reynolds number goes
> > down and achieving low drag at high and low lift coefficients becomes
> > more and more difficult.
>
> > Good stalling behavior is another factor Cole considered. *Amongst all
> > of the airfoils designed the final airfoil selected for the DuckHawk
> > is the CS33-18; it allows the aircraft to fly at low lift coefficients
> > at high speeds as well as at high lift coefficients at low speeds.
> > Winglets were considered but an evaluation of their negatives and
> > benefits indicated the DuckHawk would fly better without them when
> > real world soaring techniques were considered.
>
> > State of the art performance is what Cole is after here, plus safety
> > and relative affordability. *The 30:1 aspect ratio and its razor thin
> > wings are an obvious clue this is not your generic modern glider.
> > Eighty-pound wings will be appreciated by everyone during assembly.
> > Eighteen-meter L/D performance with a 15-meter wing span will result
> > in lower drag while circling and this plane should climb like a
> > bandit.
>
> > The ship’s lower mass will give it an induced drag advantage of 29%
> > compared to today’s 15m sailplanes at equivalent wing loadings. That
> > means better climbing. *Lower wetted area means lower parasitic drag
> > and improved high speed running. A wing loading range between 6.25 and
> > 10.0 lbs./sq. Ft. will give it ability to adapt to a wide variety of
>
> ...
>
> read more »- Hide quoted text -
>
> - Show quoted text -

gee.................maybe when pilots start racing the Duck Hawk our
Racing mag, er, I mean soaring mag will show some interest.

Brad

[Tony Condon]

Too bad it wont be in Soaring, thanks for posting it though, very
interesting!
-Tony Condon
Cherokee II N373Y

[Greg Arnold[_2_]]

Brad wrote:

>> - Show quoted text -
>
> gee.................maybe when pilots start racing the Duck Hawk our
> Racing mag, er, I mean soaring mag will show some interest.
>
> Brad
>

I just looked through the latest issue. 64 pages, and only 2 are about
racing.

[PIKflyer]

On Feb 25, 6:08*pm, Greg Arnold > wrote:
> SF wrote:
> > I wrote the following article and submitted it to Soaring for
> > publication because it was something I was interested in and I thought
> > others would be too. *It was rejected because the subject matter
> > wasn't suitable for soaring. *Greg Cole is doing something
> > extraordinary at Windward Performance and I feel that Soaring is doing
> > all of us a disservice by not putting content like this in the
> > magazine.
>
> Send it to John Roake at Gliding International in NZ, which unlike
> SOARING is edited by a gliding enthusiast.
>
>
>
> > ******************
> > My Trip To Windward Performance
>
> > At the 2008 SSA convention in Albuquerque, NM I attended Greg Cole’s
> > presentation on the new 15M sailplane he’s building called the
> > DuckHawk. * The presentation piqued my interest and I managed to
> > retain the knowledge that the DuckHawk is an American name for
> > Peregrine Falcon, the fastest moving creature on earth, and that Greg
> > Cole’s Sailplane factory is in Bend Oregon.
>
> > * *Other details stuck with me too, like an L/D of 52/1. *Minimum Sink
> > is 111 fpm; empty weight is 300 Lbs, and this Hawk has an aspect ratio
> > of 30.0:1. *The 200 Kt. VNE would make for one hot smoking final
> > glide.
>
> > When business took me to Portland, Oregon last Fall, I realized I’d be
> > fairly close to Bend. A few phone calls got me an appointment with
> > Greg Cole, president and creative force behind Windward Performance
> > Ltd, DuckHawk’s creator as well as builders of 11M span SparrowHawk.
>
> > Greg Cole has been building and flying his designs since he was a
> > kid. *He has a BSME from the University of North Dakota, and a MSAE
> > from Notre Dame. *He holds a US patent on propeller design. *His work
> > experience includes the McCauley Propeller Company, Columbia Aircraft
> > Company (chief Engineer), Cirrus Design, Lancair, and Adam Aircraft.
> > He has made significant Design contributions to several different
> > aircraft including: the Lancair Legacy, the Lancair Evolution, The
> > Columbia 300, The Chanute, The A500, and of course the SparrowHawk
> > which is the only U.S. designed sailplane to hold a world record in 30
> > years. *The Columbia 300 bears mentioning again as it was the first
> > new design certified by the FAA in 17 years, and it was a full
> > composite airframe from a new company.
>
> > For those of us that live in America’s South, the drive from Portland
> > to Bend is simply amazing. * In South Carolina we drive in one green
> > tunnel of pine trees after another, and while we have mountains, they
> > don’t have snow on them in early September like Mount Hood. *The drive
> > down through the high desert is truly beautiful - just don’t try to
> > pump your own gas. Oregon gas stations are required by state law to be
> > full service.
>
> > The modern sailplane is one truly amazing piece of machinery. *They
> > may look simple but they’re among the most sophisticated aircraft
> > flying. *I learned to fly in a Grob 103. *My first single-place glider
> > was a 1968 Open Cirrus with massive fiberglass spars, fat wings, and
> > heavy enough to send everyone on the field running the other direction
> > any time you pull your trailer into the assembly area.
>
> > I moved up to a mid-80’s LS6-a, and began teaching students in a
> > 2-33. *The historical progression from the 2-33 and its flying barn
> > door performance, to a first generation glass ship like the Cirrus, a
> > second generation glass ship like the LS6-a, and a modern glider using
> > knife like laminar-flow wings is exciting to experience firsthand.
> > One of my friends sums it up saying “these new planes just do what you
> > want them to do so much easier, and they do it so much better”.
>
> > Improvements in modern sailplane performance have been driven by
> > advances in materials, a better understanding of how to design
> > aerodynamic structures with these materials, computer modeling, and
> > leaps in understanding aerodynamic principles. Most modern sailplanes,
> > with the exception of Windward Performance’s aircraft, are built with
> > a wet, room temperature cured, epoxy resin lay up using glass, carbon,
> > or Kevlar fiber reinforcement. *The reinforcing cloth is laid into the
> > mold by hand and the epoxy squeegeed, or painted on. *This type of
> > construction process was quite an advance over previous wood and metal
> > construction and quite a bit better than “fiberglass” or polyester
> > resins or even the vinyl ester resins but still imposes several
> > limitations on how strong aircraft parts may be made.
>
> > * When the resins cure at room temperature there is fairly short
> > amount of “out-time” – the number of minutes workers have to craft the
> > part before the resin’s curing process begins. *Complicated multi-
> > layer layups have to be done quickly. *Yet fiber orientation and
> > wetout are important in critical aircraft applications. As a result
> > room-temperature resin application often means a heavier composite
> > structure to maintain structural safety. *The room temperature curing
> > of resins, causes the finished part to lose structural integrity
> > rapidly at temperatures over 140 F, which is why modern composite
> > sailplanes are painted white. *If they were painted black or even red
> > they would heat up under sunlight and loose structural integrity.
>
> > Thus Cole’s Windward Performance is the only sailplane manufacturer
> > I’m aware of to use sophisticated prepreg oven-cured carbon fiber
> > construction. *Prepreg carbon fiber is produced in a factory by
> > sandwiching a carbon fiber cloth between two epoxy resin sheets, the
> > sandwich is then run this between high-pressure rollers. *The high
> > pressure insures an even and complete epoxy coating of the fabric with
> > the ability to very precisely control the ratio of resin to fabric.
> > This allows the composite’s weight to remain low but optimized for
> > strength with very tight tolerances. *Once the fabric is epoxy coated
> > it is refrigerated for storage and transport, greatly retarding the
> > start of the curing process.
>
> > Since the resin does not cure at room temperatures there is much more
> > out-time in which to lay up the prepreg material in, say, a wing-mold
> > while avoiding mistakes from rushing. There’ more time for forming
> > complicated multi-layer configurations.
>
> > In Windward’s aircraft, the prepreg layup is vacuum-bagged to ensure
> > all air is squeezed out of the layup and the entire assembly goes into
> > an oven to cure at high temperatures. The benefits of all this are
> > lighter, far stronger and stiffer composites with a much larger
> > temperature operating range than conventional wet layup composites
> > afford.
> > Given these advantages, and given Greg Cole’s expertise and obviously
> > high standards of craftsmanship, it became clear why Windward
> > Performance uses prepregs, and why they result in the Duck Hawk’s
> > performance advantages.
>
> > A winning 15M racing sailplane moves around the course in the least
> > amount of time with the highest average cross country speed. *The key
> > to obtaining that is, naturally, minimizing the time you go slow.
> > Climbing well and going fast between thermals sounds easy, but
> > mastering this simple concept is far from easy. *Most of us with
> > modest skills in this area could use all the help we can get from the
> > aircraft.
>
> > The modeling of average cross country speeds with different
> > atmospheric conditions allowed performance simulations of different
> > design iterations to be run and small improvements or losses to be
> > determined. *The accuracy of modeling new designs was, for Cole,
> > validated by modeling current designs with known performance
> > characteristics.
>
> > Designs that can be made light with small wing areas offer improved
> > performance over conventional designs especially in tough conditions.
> > Tough conditions – small thermals, weak lift, headwinds, etc. - seem
> > to have a far greater negative impact on my contest results than do
> > the positives of favorable conditions.
>
> > Cole’s calculations show soaring with the ability to fly well with low
> > lift coefficients can also give the ability to go fast at relatively
> > low wing loadings, meaning faster average cross country speeds. *The
> > results of the modeling process indicated an optimum with a wing area
> > of 80 SQFT, and a wing loading of 8.75 LBS/SQFT.
>
> > Determining the optimum airfoil also benefits from Cole’s computer
> > modeling process. *Structural constraints start as the wing area drops
> > below 90 square feet, and wing volume available for ballast drops
> > rapidly as well. *As wing area decreases, the Reynolds number goes
> > down and achieving low drag at high and low lift coefficients becomes
> > more and more difficult.
>
> > Good stalling behavior is another factor Cole considered. *Amongst all
> > of the airfoils designed the final airfoil selected for the DuckHawk
> > is the CS33-18; it allows the aircraft to fly at low lift coefficients
> > at high speeds as well as at high lift coefficients at low speeds.
> > Winglets were considered but an evaluation of their negatives and
> > benefits indicated the DuckHawk would fly better without them when
> > real world soaring techniques were considered.
>
> > State of the art performance is what Cole is after here, plus safety
> > and relative affordability. *The 30:1 aspect ratio and its razor thin
> > wings are an obvious clue this is not your generic modern glider.
> > Eighty-pound wings will be appreciated by everyone during assembly.
> > Eighteen-meter L/D performance with a 15-meter wing span will result
> > in lower drag while circling and this plane should climb like a
> > bandit.
>
> > The ship’s lower mass will give it an induced drag advantage of 29%
> > compared to today’s 15m sailplanes at equivalent wing loadings. That
> > means better climbing. *Lower wetted area means lower parasitic drag
> > and improved high speed running. A wing loading range between 6.25 and
> > 10.0 lbs./sq. Ft. will give it ability to adapt to a wide variety of
>
> ...
>
> read more »- Hide quoted text -
>
> - Show quoted text -

[PIKflyer]

On Feb 25, 5:11*pm, SF > wrote:
> I wrote the following article and submitted it to Soaring for
> publication because it was something I was interested in and I thought
> others would be too. *It was rejected because the subject matter
> wasn't suitable for soaring. *Greg Cole is doing something
> extraordinary at Windward Performance and I feel that Soaring is doing
> all of us a disservice by not putting content like this in the
> magazine.
> ******************
> My Trip To Windward Performance
>
> At the 2008 SSA convention in Albuquerque, NM I attended Greg Cole’s
> presentation on the new 15M sailplane he’s building called the
> DuckHawk. * The presentation piqued my interest and I managed to
> retain the knowledge that the DuckHawk is an American name for
> Peregrine Falcon, the fastest moving creature on earth, and that Greg
> Cole’s Sailplane factory is in Bend Oregon.
>
> * * * * Other details stuck with me too, like an L/D of 52/1. *Minimum Sink
> is 111 fpm; empty weight is 300 Lbs, and this Hawk has an aspect ratio
> of 30.0:1. *The 200 Kt. VNE would make for one hot smoking final
> glide.
>
> When business took me to Portland, Oregon last Fall, I realized I’d be
> fairly close to Bend. A few phone calls got me an appointment with
> Greg Cole, president and creative force behind Windward Performance
> Ltd, DuckHawk’s creator as well as builders of 11M span SparrowHawk.
>
> Greg Cole has been building and flying his designs since he was a
> kid. *He has a BSME from the University of North Dakota, and a MSAE
> from Notre Dame. *He holds a US patent on propeller design. *His work
> experience includes the McCauley Propeller Company, Columbia Aircraft
> Company (chief Engineer), Cirrus Design, Lancair, and Adam Aircraft.
> He has made significant Design contributions to several different
> aircraft including: the Lancair Legacy, the Lancair Evolution, The
> Columbia 300, The Chanute, The A500, and of course the SparrowHawk
> which is the only U.S. designed sailplane to hold a world record in 30
> years. *The Columbia 300 bears mentioning again as it was the first
> new design certified by the FAA in 17 years, and it was a full
> composite airframe from a new company.
>
> For those of us that live in America’s South, the drive from Portland
> to Bend is simply amazing. * In South Carolina we drive in one green
> tunnel of pine trees after another, and while we have mountains, they
> don’t have snow on them in early September like Mount Hood. *The drive
> down through the high desert is truly beautiful - just don’t try to
> pump your own gas. Oregon gas stations are required by state law to be
> full service.
>
> The modern sailplane is one truly amazing piece of machinery. *They
> may look simple but they’re among the most sophisticated aircraft
> flying. *I learned to fly in a Grob 103. *My first single-place glider
> was a 1968 Open Cirrus with massive fiberglass spars, fat wings, and
> heavy enough to send everyone on the field running the other direction
> any time you pull your trailer into the assembly area.
>
> I moved up to a mid-80’s LS6-a, and began teaching students in a
> 2-33. *The historical progression from the 2-33 and its flying barn
> door performance, to a first generation glass ship like the Cirrus, a
> second generation glass ship like the LS6-a, and a modern glider using
> knife like laminar-flow wings is exciting to experience firsthand.
> One of my friends sums it up saying “these new planes just do what you
> want them to do so much easier, and they do it so much better”.
>
> Improvements in modern sailplane performance have been driven by
> advances in materials, a better understanding of how to design
> aerodynamic structures with these materials, computer modeling, and
> leaps in understanding aerodynamic principles. Most modern sailplanes,
> with the exception of Windward Performance’s aircraft, are built with
> a wet, room temperature cured, epoxy resin lay up using glass, carbon,
> or Kevlar fiber reinforcement. *The reinforcing cloth is laid into the
> mold by hand and the epoxy squeegeed, or painted on. *This type of
> construction process was quite an advance over previous wood and metal
> construction and quite a bit better than “fiberglass” or polyester
> resins or even the vinyl ester resins but still imposes several
> limitations on how strong aircraft parts may be made.
>
> * When the resins cure at room temperature there is fairly short
> amount of “out-time” – the number of minutes workers have to craft the
> part before the resin’s curing process begins. *Complicated multi-
> layer layups have to be done quickly. *Yet fiber orientation and
> wetout are important in critical aircraft applications. As a result
> room-temperature resin application often means a heavier composite
> structure to maintain structural safety. *The room temperature curing
> of resins, causes the finished part to lose structural integrity
> rapidly at temperatures over 140 F, which is why modern composite
> sailplanes are painted white. *If they were painted black or even red
> they would heat up under sunlight and loose structural integrity.
>
> Thus Cole’s Windward Performance is the only sailplane manufacturer
> I’m aware of to use sophisticated prepreg oven-cured carbon fiber
> construction. *Prepreg carbon fiber is produced in a factory by
> sandwiching a carbon fiber cloth between two epoxy resin sheets, the
> sandwich is then run this between high-pressure rollers. *The high
> pressure insures an even and complete epoxy coating of the fabric with
> the ability to very precisely control the ratio of resin to fabric.
> This allows the composite’s weight to remain low but optimized for
> strength with very tight tolerances. *Once the fabric is epoxy coated
> it is refrigerated for storage and transport, greatly retarding the
> start of the curing process.
>
> Since the resin does not cure at room temperatures there is much more
> out-time in which to lay up the prepreg material in, say, a wing-mold
> while avoiding mistakes from rushing. There’ more time for forming
> complicated multi-layer configurations.
>
> In Windward’s aircraft, the prepreg layup is vacuum-bagged to ensure
> all air is squeezed out of the layup and the entire assembly goes into
> an oven to cure at high temperatures. The benefits of all this are
> lighter, far stronger and stiffer composites with a much larger
> temperature operating range than conventional wet layup composites
> afford.
> Given these advantages, and given Greg Cole’s expertise and obviously
> high standards of craftsmanship, it became clear why Windward
> Performance uses prepregs, and why they result in the Duck Hawk’s
> performance advantages.
>
> A winning 15M racing sailplane moves around the course in the least
> amount of time with the highest average cross country speed. *The key
> to obtaining that is, naturally, minimizing the time you go slow.
> Climbing well and going fast between thermals sounds easy, but
> mastering this simple concept is far from easy. *Most of us with
> modest skills in this area could use all the help we can get from the
> aircraft.
>
> The modeling of average cross country speeds with different
> atmospheric conditions allowed performance simulations of different
> design iterations to be run and small improvements or losses to be
> determined. *The accuracy of modeling new designs was, for Cole,
> validated by modeling current designs with known performance
> characteristics.
>
> Designs that can be made light with small wing areas offer improved
> performance over conventional designs especially in tough conditions.
> Tough conditions – small thermals, weak lift, headwinds, etc. - seem
> to have a far greater negative impact on my contest results than do
> the positives of favorable conditions.
>
> Cole’s calculations show soaring with the ability to fly well with low
> lift coefficients can also give the ability to go fast at relatively
> low wing loadings, meaning faster average cross country speeds. *The
> results of the modeling process indicated an optimum with a wing area
> of 80 SQFT, and a wing loading of 8.75 LBS/SQFT.
>
> Determining the optimum airfoil also benefits from Cole’s computer
> modeling process. *Structural constraints start as the wing area drops
> below 90 square feet, and wing volume available for ballast drops
> rapidly as well. *As wing area decreases, the Reynolds number goes
> down and achieving low drag at high and low lift coefficients becomes
> more and more difficult.
>
> Good stalling behavior is another factor Cole considered. *Amongst all
> of the airfoils designed the final airfoil selected for the DuckHawk
> is the CS33-18; it allows the aircraft to fly at low lift coefficients
> at high speeds as well as at high lift coefficients at low speeds.
> Winglets were considered but an evaluation of their negatives and
> benefits indicated the DuckHawk would fly better without them when
> real world soaring techniques were considered.
>
> State of the art performance is what Cole is after here, plus safety
> and relative affordability. *The 30:1 aspect ratio and its razor thin
> wings are an obvious clue this is not your generic modern glider.
> Eighty-pound wings will be appreciated by everyone during assembly.
> Eighteen-meter L/D performance with a 15-meter wing span will result
> in lower drag while circling and this plane should climb like a
> bandit.
>
> The ship’s lower mass will give it an induced drag advantage of 29%
> compared to today’s 15m sailplanes at equivalent wing loadings. That
> means better climbing. *Lower wetted area means lower parasitic drag
> and improved high speed running. A wing loading range between 6.25 and
> 10.0 lbs./sq. Ft. will give it ability to adapt to a wide variety of
> soaring conditions - a plane that will get you quickly around the
> course on the tough days and fly faster than anything else out there
> now on really good days.
>
> Before my trip to Windward Performance I was unaware of the complexity
> of the sailplane manufacturing process. *The plugs and molds required
> to produce a sailplane, fill a good sized warehouse even without
> working room around them. *The design and production capabilities of
> this small sailplane operation ...
>
> read more »

[Brad[_2_]]

On Feb 25, 7:11*pm, Greg Arnold > wrote:
> Brad wrote:
> >> - Show quoted text -
>
> > gee.................maybe when pilots start racing the Duck Hawk our
> > Racing mag, er, I mean soaring mag will show some interest.
>
> > Brad
>
> I just looked through the latest issue. *64 pages, and only 2 are about
> racing.

I would have thought the new Soaring Tech by Bill Collum would be
interested in this article.

Judging by the feedback we get on Bob's HP-24 blog there is a lot of
interest out there when it comes to how gliders are made.

Brad

[Mike the Strike]

Perhaps folks are (justifiably?) skeptical about a sailplane that
hasn't even been built yet, let alone flown.

With photos of an actual aircraft and real performance measurements,
you'll find it easier to find a publisher.

.....and what sort of name is Duck Hawk? I wonder how many folks, let
alone Americans, know that this is one historical local name for the
Peregrine Falcon. Naming is a very important marketing tool. A
product's name conveys an image of the product or brand. If you have
to explain what the name means, you've already lost. At least they
could have called it Bullet Hawk - at least that sounds fast!

Mike

[Nyal Williams[_2_]]

Peregrine is already taken in this country by a metal two-seater; why not
just call it Falcon?

At 05:21 26 February 2009, Mike the Strike wrote:
>Perhaps folks are (justifiably?) skeptical about a sailplane that
>hasn't even been built yet, let alone flown.
>
>With photos of an actual aircraft and real performance measurements,
>you'll find it easier to find a publisher.
>
>.....and what sort of name is Duck Hawk? I wonder how many folks, let
>alone Americans, know that this is one historical local name for the
>Peregrine Falcon. Naming is a very important marketing tool. A
>product's name conveys an image of the product or brand. If you have
>to explain what the name means, you've already lost. At least they
>could have called it Bullet Hawk - at least that sounds fast!
>
>Mike
>

[[email protected]]

On Feb 26, 1:00*am, Nyal Williams > wrote:
> Peregrine is already taken in this country by a metal two-seater; why not
> just call it Falcon?
>
Falcon was used by Advanced Soaring Concepts, of California (now
defunct), for the 15m flapped variant of their American Spirit
standard class; both were kit-built fibre-glass ships, very similar in
appearance to a Ventus. (No, I don't want to "go there"!).

Some guys at my club bought the rights and molds for the Spirit/
Falcon, plus got 2 Spirits (and supposedly the first Falcon, if it can
be found). Nice looking aircraft.

[[email protected]]

Great Article. Having spent some considerable time with Greg while in
Bend in preparation for racing his Sparrowhawk at the 2008 Sports Nats
in Montague last year, I believe Greg is right on the cusp of creating
AND producing a glider that will make many current glider pilots say
"Wow!" and then line-up for one. While finances are tight (but then
again whose aren't), this ship is taking shape very rapidly and I
would not discount its first flight this summer. I've seen the wing
molds and plugs and the cockpit/control mock-up and it is all going to
be first class. From last report parts of the wing were already laid
up last fall. If the numbers are even close to what is calculated,
this ship will be one to watch for sure.

Tim McAllister EY

[Bob Kuykendall]

> State of the art performance is what Cole is after here, plus safety
> and relative affordability.

Definitely, $92,000 is quite affordable if you are out to win the 15m
nationals and you're willing and able to spend what it takes.

Thanks, Bob K.

[[email protected]]

This is an informative, important and well-written article, which
deserved to be published in "Soaring". However, IMHO, the chosen name
for this new glider is unfortunate. Not only is the term "Duck Hawk"
obsolete, the word "Duck" hardly imparts the intended image. A
totally unscientific questionnaire (my wife) revealed that the term
implies awkwardness. Checking my Sibley "Guide to Birds", there are
any number of North American birds whose name could be used. "Merlin"
comes to mind: "small, compact, powerful and very aggressive". Oh
well, just my 2 (devalued) cents worth.

Cheers, Charles

[[email protected]]

It is interesting to see how the discussion is drifting a little bit
off the topic. Many glider manufacturers do not give names to their
products, and yet still have been able to built respectable
reputation. For designer who gave Sparrow Hawk name to his first
glider, it appears almost a natural consequence to name the 15M racer
as Duck Hawk, particularly that both of the gliders will share the
fuselage [at least the outside shell, since Duck Hawk will obviously
have retractable landing gear]. Diana implies beauty, not necessarily
the performance, yet her mark does not remain unnoticed.

In a world of modern, high performance glider design, Greg Cole
deserves huge recognition, for now at least for trying, but doubtful
the Duck Hawk will not deliver on the promise. For those few that had
the privilege of looking at the new wing tools for the glider, I would
dare to say, they already know the answer. Would it not be the subject
of pride to see the top performing racer coming from the US?

[Jp Mobo]

At 21:28 26 February 2009, wrote:
>It is interesting to see how the discussion is drifting a little bit
>off the topic. Many glider manufacturers do not give names to their
>products, and yet still have been able to built respectable
>reputation. For designer who gave Sparrow Hawk name to his first
>glider, it appears almost a natural consequence to name the 15M racer
>as Duck Hawk, particularly that both of the gliders will share the
>fuselage [at least the outside shell, since Duck Hawk will obviously
>have retractable landing gear]. Diana implies beauty, not necessarily
>the performance, yet her mark does not remain unnoticed.
>
>In a world of modern, high performance glider design, Greg Cole
>deserves huge recognition, for now at least for trying, but doubtful
>the Duck Hawk will not deliver on the promise. For those few that had
>the privilege of looking at the new wing tools for the glider, I would
>dare to say, they already know the answer. Would it not be the subject
>of pride to see the top performing racer coming from the US?
>



Special design features have their own drawbacks - carbon fibre is light
but it doesn't give in a crash, has this been accounted for?

btw, the Diana sailplane is sleek but it seems to almost guarantee a
tailboom snapoff in a mild groundloop.

[jb92563]

I think that these forums are more read than the Magazine, but they
would rather print that story when there is some real data behind it.

Very interesting stuff.

The Light Hawk is another Carbon/glass ship that is made in the US in
CA, and costs around $100k.

It has a different mission....minimum sink to be able to soar micro
lift (Search "Garry Osaba" for details and a fascinating story)

It literally can soar on cow farts.

Even at that cost his profit margin is small.

I spoke to the owner/designer Danny Howell a few months back and he
says that most sales are coming from Europe.

Fascinating talk as you start to uncover the posibilities and
different flight regimes.

Ray

[Jim White[_3_]]

Maybe it should be called a Charles, after what he did to Diana?

[Brad[_2_]]

On Feb 27, 8:00*am, Jim White > wrote:
> Maybe it should be called a Charles, after what he did to Diana?

how about a w(h)ale?!

Brad

[[email protected][_2_]]

While the DuckHawk sounds interesting, and I hope it works, I'm
surprised that it is being designed as a 15m flapped ship. Most of
the flapped development nowadays is in the 18m class - and while the
15m racing class is still safe, it's probably not where the real
action is going to be in the future (and I say this as a 15m racer
myself).

It would seem that the Duckhawk would have more international appeal
as a Standard class (15m no flaps) ship - wonder how it would perform
without flaps?

Watching with interest....

Kirk
66

[Greg Arnold[_2_]]

wrote:
> While the DuckHawk sounds interesting, and I hope it works, I'm
> surprised that it is being designed as a 15m flapped ship. Most of
> the flapped development nowadays is in the 18m class - and while the
> 15m racing class is still safe, it's probably not where the real
> action is going to be in the future (and I say this as a 15m racer
> myself).


Yes, that does make one wonder about the commercial viability of this
new glider.


>
> It would seem that the Duckhawk would have more international appeal
> as a Standard class (15m no flaps) ship - wonder how it would perform
> without flaps?
>
> Watching with interest....
>
> Kirk
> 66

[Bob Kuykendall]

On Feb 27, 9:42*am, " >
wrote:
> While the DuckHawk sounds interesting, and I hope it works, I'm
> surprised that it is being designed as a 15m flapped ship. *Most of
> the flapped development nowadays is in the 18m class - and while the
> 15m racing class is still safe, it's probably not where the real
> action is going to be in the future (and I say this as a 15m racer
> myself).
>
> It would seem that the Duckhawk would have more international appeal
> as a Standard class (15m no flaps) ship - wonder how it would perform
> without flaps?
>
> Watching with interest....

At ESA Tehachapi '08, Greg did a presentation on the GosHawk electric
airplane he is working on, probably with an eye towards competing in
the green aviation contest that NASA and CAFE are attempting to
collaborate on. Anyhow, it was pretty clear from the specs that the
GosHawk airplane uses the same wing shapes as the DuckHawk sailplane,
though the GosHawk's greater fuselage width and much greater non-
lifting weight probably require some structural differences.

Those who believe that breakthroughs in battery technology are right
around the corner will be really interested in the GosHawk. Greg is
scheduled to be in the Bay Area to give a presentation at the CAFE 3rd
Annual Electric Aircraft Symposium on April 24, 2009 at the Hiller
Aviation Museum in San Carlos, California. You can register online for
only $249, but it's $310 at the door:

http://cafefoundation.org/v2/pav_eas_2009.php

Given that the DuckHawk wings (and their tooling) have multiple
applications, it was probably a pretty closely calibrated decision to
optimize their sailplane application for the waning 15-meter racing
class. And while the fine planform optimization required to achieve
their promised performance probably precludes tip extensions to 18m, I
wouldn't be too surprised to see a version that adds a meter and a
half on a side at the inboard end.

Thanks, and best regards to all
Bob K.
http://www.hpaircraft.com/hp-24

[noel.wade]

....and since we're spinning a bit off-topic, here's an update on the
whole "new battery technology" front:

http://gas2.org/2009/01/21/silicon-nanowire-batteries-take-two-the-core-shell-approach/

Having batteries store 3x the current charge of the Antares (or the
same charge for 1/3rd of the weight) sounds nice! Peering into my
(cludy, amateur) crystal ball, I'd bet money that these cells are on
the market in 3 years. The global economic climate isn't favorable
for new entreprenurial investments; but at the same time there's
plenty of excess factory capacity around the world right now, lots of
unemployed people to work in the factories, and batteries are going to
be in high demand for the foreseeable future.

Take care,

--Noel

[Frank[_1_]]

On Feb 25, 8:11*pm, SF > wrote:
> I wrote the following article and submitted it to Soaring for
> publication because it was something I was interested in and I thought
> others would be too. *It was rejected because the subject matter
> wasn't suitable for soaring. *Greg Cole is doing something
> extraordinary at Windward Performance and I feel that Soaring is doing
> all of us a disservice by not putting content like this in the
> magazine.
> ******************


Hm, American technical know-how being used in creative ways to further
soaring and challenge a foreign monopoly... Yep - not suitable for
Boaring magazine ;-)

Frank (TA)

[Mike the Strike]

On Feb 27, 2:23*pm, Frank > wrote:
> On Feb 25, 8:11*pm, SF > wrote:
>
> > I wrote the following article and submitted it to Soaring for
> > publication because it was something I was interested in and I thought
> > others would be too. *It was rejected because the subject matter
> > wasn't suitable for soaring. *Greg Cole is doing something
> > extraordinary at Windward Performance and I feel that Soaring is doing
> > all of us a disservice by not putting content like this in the
> > magazine.
> > ******************
>
> Hm, American technical know-how being used in creative ways to further
> soaring and challenge a foreign monopoly... *Yep - not suitable for
> Boaring magazine ;-)
>
> Frank (TA)

While we all wish an American entrepreneur all the best in developing
and selling a new sailplane, the article sounds to me more like an
advertising brochure than a factual report. Very long on hype and
short on verifiable facts - especially as to how the new ship will
fly.

Since the factory has been taking deposits for over a year, there is
clearly some doubt as to if and when the new ship will appear. The
factory has a number of other projects on the go and this one may not
be their top priority. (If I were in their shoes, I'd probably
concentrate on producing a lightweight UAV for the military - a market
they've already discovered).

Windward may well produce a sailplane with the best 15-meter
performance in the world, but until one is actually built and flown we
have no way of knowing whether all the computer modeling predictions
are true.

Mike

[[email protected]]

On Feb 27, 2:59*pm, "noel.wade" > wrote:
> ...and since we're spinning a bit off-topic, here's an update on the
> whole "new battery technology" front:
>
> http://gas2.org/2009/01/21/silicon-nanowire-batteries-take-two-the-co...
>
> Having batteries store 3x the current charge of the Antares (or the
> same charge for 1/3rd of the weight) sounds nice! *Peering into my
> (cludy, amateur) crystal ball, I'd bet money that these cells are on
> the market in 3 years. *The global economic climate isn't favorable
> for new entreprenurial investments; but at the same time there's
> plenty of excess factory capacity around the world right now, lots of
> unemployed people to work in the factories, and batteries are going to
> be in high demand for the foreseeable future.
>
> Take care,
>
> --Noel

Along those lines, I'm very excited about Eestor. I hope they can
produce what they say they can. The power-to-weight ratio would be a
huge advantage for electric aircraft.

[Tuno]

<snip> it's probably not where the real action is going to be in the
future </snip>

Certainly not the near future!

2009 Nationals registration counts as of 27 Feb --

15M: 49
18M: 12

And I'd go to the 15M nats too (I have a glider that will do both)
were it not on the east coast!

..02NO

[noel.wade]

On Feb 27, 2:10*pm, wrote:

> Along those lines, I'm very excited about Eestor. I hope they can
> produce what they say they can. The power-to-weight ratio would be a
> huge advantage for electric aircraft.- Hide quoted text -
>

Ultracapacitors have some amazing advantages (especially in terms of
cycle time / recharge time)... But even these new ones by companies
like AltairNano and EEStor are turning out to have disappointing
problems or real-world constraints (i.e. much lower useable voltages
or lifetimes compared to the "on-paper" specs and energy density).
EEStor has missed milestones for over a year (2007 stuff was pushed to
mid-2008, and recently pushed back again to mid-2009)... Not a good
sign! http://earth2tech.com/2008/12/26/eestor-missing-zenn-milestones-in-2008/

I personally believe that Lithium Battery technology is the more
likely avenue for progress - since batteries can be dropped into
existing systems without having to re-wire them (to accept capacitor
discharge pulses or other unique systems). Plus, there are several
different avenues of serious research into lithium battery technology
(Yi Cui's group is just one of them) - so the likelihood of at least
one of them coming to market with a viable product is pretty high...

Take care,

--Noel

[[email protected][_2_]]

On Feb 27, 4:15*pm, Tuno > wrote:
> <snip> it's probably not where the real action is going to be in the
> future </snip>
>
> Certainly not the near future!
>
> 2009 Nationals registration counts as of 27 Feb --
>
> * * 15M: 49
> * * 18M: 12
>
> And I'd go to the 15M nats too (I have a glider that will do both)
> were it not on the east coast!
>
> .02NO

Agreed! That's why I'm smack in the middle of those 49 15Ms!

But look at what is being built right now, and project that forward a
few years....

Of course, that just means it'll be more fun to beat the snotty-nosed
18m ships with a ratty old 15m, winglets (draglets) be damned!

Is this a great sport or what!

Kirk
66

[Frank[_1_]]

On Feb 27, 4:56*pm, Mike the Strike > wrote:
> On Feb 27, 2:23*pm, Frank > wrote:
>
>
>
>
>
> > On Feb 25, 8:11*pm, SF > wrote:
>
> > > I wrote the following article and submitted it to Soaring for
> > > publication because it was something I was interested in and I thought
> > > others would be too. *It was rejected because the subject matter
> > > wasn't suitable for soaring. *Greg Cole is doing something
> > > extraordinary at Windward Performance and I feel that Soaring is doing
> > > all of us a disservice by not putting content like this in the
> > > magazine.
> > > ******************
>
> > Hm, American technical know-how being used in creative ways to further
> > soaring and challenge a foreign monopoly... *Yep - not suitable for
> > Boaring magazine ;-)
>
> > Frank (TA)
>
> While we all wish an American entrepreneur all the best in developing
> and selling a new sailplane, the article sounds to me more like an
> advertising brochure than a factual report. Very long on hype and
> short on verifiable facts - especially as to how the new ship will
> fly.
>
> Since the factory has been taking deposits for over a year, there is
> clearly some doubt as to if and when the new ship will appear. *The
> factory has a number of other projects on the go and this one may not
> be their top priority. *(If I were in their shoes, I'd probably
> concentrate on producing a lightweight UAV for the military - a market
> they've already discovered).
>
> Windward may well produce a sailplane with the best 15-meter
> performance in the world, but until one is actually built and flown we
> have no way of knowing whether all the computer modeling predictions
> are true.
>
> Mike- Hide quoted text -
>
> - Show quoted text -

Mike,

Yep - I agree with you 100%. However, IMHO, this is just the sort of
thing that *should* be published in Soaring. So what if it doesn't
work out - it's still an exciting development and should be
publicized. Maybe I missed the part where it says that any hint of
speculation or (heaven forbid - enthusiasm!) is grounds for
rejection. Soaring magazine should be leading the charge here, with
photos of the factory floor and interviews with the builder, but
instead it seems to be ignoring the whole thing.

Frank(TA)

[Bob Kuykendall]

On Feb 27, 6:00*pm, Frank > wrote:
> Soaring magazine should be leading the charge here, with
> photos of the factory floor and interviews with the builder, but
> instead it seems to be ignoring the whole thing.

My own high-performance carbon fiber sailplane project got coverage in
the national soaring press last year.

In Canada:

http://www.sac.ca/index.php?option=com_docman&task=doc_download&gid=398&Itemid=88

Thanks, Bob K.
www.hpaircraft.com

[Eric Greenwell]

wrote:

> It would seem that the Duckhawk would have more international appeal
> as a Standard class (15m no flaps) ship - wonder how it would perform
> without flaps?

It sure wouldn't need that 200 knot Vne, would it? Flaps are essential
to get the wide speed range that makes the the 200 knot Vne useful. My
understanding is the airfoil is optimized for climbing and very high
speed flight.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[Bob Kuykendall]

On Feb 27, 8:55*pm, Eric Greenwell > wrote:

> My understanding is the airfoil is optimized for climbing and very high
> speed flight.

Eric, that kinda stretches the meaning of the word "optimize" a bit.

Thanks, Bob K.

[Greg Arnold[_2_]]

Bob Kuykendall wrote:
> On Feb 27, 8:55 pm, Eric Greenwell > wrote:
>
>> My understanding is the airfoil is optimized for climbing and very high
>> speed flight.
>
> Eric, that kinda stretches the meaning of the word "optimize" a bit.
>
> Thanks, Bob K.


It is an optimized compromise.

[Peter Purdie[_3_]]

If you design for high Clmax and stall at high alpha (to give good climb
performance) and very low drag at the high speed end, without worrying
about L/D ratio in the middle, then that fills Eric's statement
definition. Doing it is another matter........

At 06:54 28 February 2009, Greg Arnold wrote:
>Bob Kuykendall wrote:
>> On Feb 27, 8:55 pm, Eric Greenwell wrote:
>>
>>> My understanding is the airfoil is optimized for climbing and very
high
>>> speed flight.
>>
>> Eric, that kinda stretches the meaning of the word "optimize" a bit.
>>
>> Thanks, Bob K.
>
>
>It is an optimized compromise.
>

[[email protected]]

The DuckHawk wing IS optimised for high speed and low speed flight. A
tremendous amount of effort went into creating a wing that would work
well at slow speeds with the flaps down, and also work very well at
high speeds with flaps up.

Additionally, Greg did a lot of analysis of how to maximize the cross
country speed. To simplify greatly, the result was to climb really
fast and run really fast. That actually simplified things a little
with the flaps. Basically, one would fly with flaps down while
climbing and then transition directly to flaps up and run fast to find
the next thermal. Intermediate speeds and flap positions were not
that necessary. So, the flaps up/high speed case and the flaps down/
low speed point were optimized. Of course, in the real world, there
might be times when you don't want to do exactly what the theory says,
so last I heard, the flaps will just have 3 positions: up, zero, and
down (a landing position was discussed, but I don't know if it is
incorporated). Quite a lot of effort was also made to give a fairly
wide performance range to each position. So, while it is optimized
for run and climb, there won't be a big hole in the middle of the
polar.

Doug T.

On Feb 28, 6:46*am, Bob Kuykendall > wrote:
> On Feb 27, 8:55*pm, Eric Greenwell > wrote:
>
> > My understanding is the airfoil is optimized for climbing and very high
> > speed flight.
>
> Eric, that kinda stretches the meaning of the word "optimize" a bit.
>
> Thanks, Bob K.

[John Scott[_2_]]

I just checked last months issue of SOARING. There was an article on the
ARCUS - a sailplane that has yet to fly.

I've also recently been reading back thru old issue of SOARING from our club
library. In the late '70s and early '80s it appears every issue has an
article on the latest homebuilt news. Nearly all of this is about
sailplanes that had yet to be built or fly.

I think the article should have been published by SOARING.

John

[[email protected]]

On Feb 28, 6:54*am, wrote:
> The DuckHawk wing IS optimised for high speed and low speed flight. *A
> tremendous amount of effort went into creating a wing that would work
> well at slow speeds with the flaps down, and also work very well at
> high speeds with flaps up.
>
> Additionally, Greg did a lot of analysis of how to maximize the cross
> country speed. *To simplify greatly, the result was to climb really
> fast and run really fast. *That actually simplified things a little
> with the flaps. *Basically, one would fly with flaps down while
> climbing and then transition directly to flaps up and run fast to find
> the next thermal. *Intermediate speeds and flap positions were not
> that necessary. * So, the flaps up/high speed case and the flaps down/
> low speed point were optimized. *Of course, in the real world, there
> might be times when you don't want to do exactly what the theory says,
> so last I heard, the flaps will just have 3 positions: up, zero, and
> down (a landing position was discussed, but I don't know if it is
> incorporated). *Quite a lot of effort was also made to give a fairly
> wide performance range to each position. *So, while it is optimized
> for run and climb, there won't be a big hole in the middle of the
> polar.

It seem they are simply taking the historical trend to the next
logical step. For 20 years or more now designers have be trying to
optimize around a design point that represents typical cruise speed,
rather than trying to increase best L/D, for instance. With advances
in materials you can make a lighter, smaller wetted area glider that
has less form drag and therefore pushes the "knee" in the polar to a
higher speed. If you can find some magic in the airfoil/flap design
then maybe you can push the overall design even further along these
same lines, but that is harder to do I think. For a current generation
15M gilders the knee is around 90kts.

Keep in mind that the polar of any glider is a continuous curve and
the designer will still optimize flap settings, etc. to match a
specific climb rate (and McCready setting) that will get you to a
specific cruise speed that is optimal to maximize cross-country
speed. If you pick a planform/airfoil/flap arrangement to suit a
particularly high cruise speed you are implicitly designing the glider
around stronger soaring conditions. Dick Schreder tried this in 1969
with the HP-15, (although without benefit of materials/construction
innovations at play with the Duckhawk).

When people say that the Duckhawk is "optimized" for very high speed
cruise I immediately wonder how high? I can see somewhat higher speeds
(maybe 100-110kts) driven by the construction innovations. I can maybe
see going a little higher to optimize around stronger conditions - but
you need to be careful about going too far and having a glider that
does poorly in weak weather, a la HP-15. I don't see the point in
setting things up for ultra-high cruise speeds unless you want a
glider that is optimized around wave record flying - but that was
another thread...

I am intrigued - can't wait to see it fly.

9B

[Wayne Paul]

For those of you who haven't been around forever, only two HP-15s were
built. The original design called for a 15 meter wing with an extreme aspect
ratio of 33 to 1. As a result of Dick Schreder placing 65th in the US
Nationals both '15s have been re-winged. The prototype now has a HP-16 wing
and the other one sports a HP-18 wing.
The HP-15 fuselage is very similar to the HP-14 except that the 1-inch
square-steel-tubing cockpit framing has been replaced by aluminum tubing.
The cockpit is large enough to provide adequate room for a 6' 4" pilot.

Wayne

HP-14 "6F"

http://www.soaridaho.com/Schreder

> wrote in message
...
On Feb 28, 6:54 am, wrote:


.... Snip...

When people say that the Duckhawk is "optimized" for very high speed
cruise I immediately wonder how high? I can see somewhat higher speeds
(maybe 100-110kts) driven by the construction innovations. I can maybe
see going a little higher to optimize around stronger conditions - but
you need to be careful about going too far and having a glider that
does poorly in weak weather, a la HP-15. I don't see the point in
setting things up for ultra-high cruise speeds unless you want a
glider that is optimized around wave record flying - but that was
another thread...

I am intrigued - can't wait to see it fly.

9B

[[email protected]]

On Feb 25, 5:11*pm, SF > wrote:
> I wrote the following article and submitted it to Soaring for
> publication because it was something I was interested in and I thought
> others would be too. *It was rejected because the subject matter
> wasn't suitable for soaring. *Greg Cole is doing something
> extraordinary at Windward Performance and I feel that Soaring is doing
> all of us a disservice by not putting content like this in the
> magazine.
> ******************
> My Trip To Windward Performance
>
> At the 2008 SSA convention in Albuquerque, NM I attended Greg Cole’s
> presentation on the new 15M sailplane he’s building called the
> DuckHawk. * The presentation piqued my interest and I managed to
> retain the knowledge that the DuckHawk is an American name for
> Peregrine Falcon, the fastest moving creature on earth, and that Greg
> Cole’s Sailplane factory is in Bend Oregon.
>
> * * * * Other details stuck with me too, like an L/D of 52/1. *Minimum Sink
> is 111 fpm; empty weight is 300 Lbs, and this Hawk has an aspect ratio
> of 30.0:1. *The 200 Kt. VNE would make for one hot smoking final
> glide.
>
> When business took me to Portland, Oregon last Fall, I realized I’d be
> fairly close to Bend. A few phone calls got me an appointment with
> Greg Cole, president and creative force behind Windward Performance
> Ltd, DuckHawk’s creator as well as builders of 11M span SparrowHawk.
>
> Greg Cole has been building and flying his designs since he was a
> kid. *He has a BSME from the University of North Dakota, and a MSAE
> from Notre Dame. *He holds a US patent on propeller design. *His work
> experience includes the McCauley Propeller Company, Columbia Aircraft
> Company (chief Engineer), Cirrus Design, Lancair, and Adam Aircraft.
> He has made significant Design contributions to several different
> aircraft including: the Lancair Legacy, the Lancair Evolution, The
> Columbia 300, The Chanute, The A500, and of course the SparrowHawk
> which is the only U.S. designed sailplane to hold a world record in 30
> years. *The Columbia 300 bears mentioning again as it was the first
> new design certified by the FAA in 17 years, and it was a full
> composite airframe from a new company.
>
> For those of us that live in America’s South, the drive from Portland
> to Bend is simply amazing. * In South Carolina we drive in one green
> tunnel of pine trees after another, and while we have mountains, they
> don’t have snow on them in early September like Mount Hood. *The drive
> down through the high desert is truly beautiful - just don’t try to
> pump your own gas. Oregon gas stations are required by state law to be
> full service.
>
> The modern sailplane is one truly amazing piece of machinery. *They
> may look simple but they’re among the most sophisticated aircraft
> flying. *I learned to fly in a Grob 103. *My first single-place glider
> was a 1968 Open Cirrus with massive fiberglass spars, fat wings, and
> heavy enough to send everyone on the field running the other direction
> any time you pull your trailer into the assembly area.
>
> I moved up to a mid-80’s LS6-a, and began teaching students in a
> 2-33. *The historical progression from the 2-33 and its flying barn
> door performance, to a first generation glass ship like the Cirrus, a
> second generation glass ship like the LS6-a, and a modern glider using
> knife like laminar-flow wings is exciting to experience firsthand.
> One of my friends sums it up saying “these new planes just do what you
> want them to do so much easier, and they do it so much better”.
>
> Improvements in modern sailplane performance have been driven by
> advances in materials, a better understanding of how to design
> aerodynamic structures with these materials, computer modeling, and
> leaps in understanding aerodynamic principles. Most modern sailplanes,
> with the exception of Windward Performance’s aircraft, are built with
> a wet, room temperature cured, epoxy resin lay up using glass, carbon,
> or Kevlar fiber reinforcement. *The reinforcing cloth is laid into the
> mold by hand and the epoxy squeegeed, or painted on. *This type of
> construction process was quite an advance over previous wood and metal
> construction and quite a bit better than “fiberglass” or polyester
> resins or even the vinyl ester resins but still imposes several
> limitations on how strong aircraft parts may be made.
>
> * When the resins cure at room temperature there is fairly short
> amount of “out-time” – the number of minutes workers have to craft the
> part before the resin’s curing process begins. *Complicated multi-
> layer layups have to be done quickly. *Yet fiber orientation and
> wetout are important in critical aircraft applications. As a result
> room-temperature resin application often means a heavier composite
> structure to maintain structural safety. *The room temperature curing
> of resins, causes the finished part to lose structural integrity
> rapidly at temperatures over 140 F, which is why modern composite
> sailplanes are painted white. *If they were painted black or even red
> they would heat up under sunlight and loose structural integrity.
>
> Thus Cole’s Windward Performance is the only sailplane manufacturer
> I’m aware of to use sophisticated prepreg oven-cured carbon fiber
> construction. *Prepreg carbon fiber is produced in a factory by
> sandwiching a carbon fiber cloth between two epoxy resin sheets, the
> sandwich is then run this between high-pressure rollers. *The high
> pressure insures an even and complete epoxy coating of the fabric with
> the ability to very precisely control the ratio of resin to fabric.
> This allows the composite’s weight to remain low but optimized for
> strength with very tight tolerances. *Once the fabric is epoxy coated
> it is refrigerated for storage and transport, greatly retarding the
> start of the curing process.
>
> Since the resin does not cure at room temperatures there is much more
> out-time in which to lay up the prepreg material in, say, a wing-mold
> while avoiding mistakes from rushing. There’ more time for forming
> complicated multi-layer configurations.
>
> In Windward’s aircraft, the prepreg layup is vacuum-bagged to ensure
> all air is squeezed out of the layup and the entire assembly goes into
> an oven to cure at high temperatures. The benefits of all this are
> lighter, far stronger and stiffer composites with a much larger
> temperature operating range than conventional wet layup composites
> afford.
> Given these advantages, and given Greg Cole’s expertise and obviously
> high standards of craftsmanship, it became clear why Windward
> Performance uses prepregs, and why they result in the Duck Hawk’s
> performance advantages.
>
> A winning 15M racing sailplane moves around the course in the least
> amount of time with the highest average cross country speed. *The key
> to obtaining that is, naturally, minimizing the time you go slow.
> Climbing well and going fast between thermals sounds easy, but
> mastering this simple concept is far from easy. *Most of us with
> modest skills in this area could use all the help we can get from the
> aircraft.
>
> The modeling of average cross country speeds with different
> atmospheric conditions allowed performance simulations of different
> design iterations to be run and small improvements or losses to be
> determined. *The accuracy of modeling new designs was, for Cole,
> validated by modeling current designs with known performance
> characteristics.
>
> Designs that can be made light with small wing areas offer improved
> performance over conventional designs especially in tough conditions.
> Tough conditions – small thermals, weak lift, headwinds, etc. - seem
> to have a far greater negative impact on my contest results than do
> the positives of favorable conditions.
>
> Cole’s calculations show soaring with the ability to fly well with low
> lift coefficients can also give the ability to go fast at relatively
> low wing loadings, meaning faster average cross country speeds. *The
> results of the modeling process indicated an optimum with a wing area
> of 80 SQFT, and a wing loading of 8.75 LBS/SQFT.
>
> Determining the optimum airfoil also benefits from Cole’s computer
> modeling process. *Structural constraints start as the wing area drops
> below 90 square feet, and wing volume available for ballast drops
> rapidly as well. *As wing area decreases, the Reynolds number goes
> down and achieving low drag at high and low lift coefficients becomes
> more and more difficult.
>
> Good stalling behavior is another factor Cole considered. *Amongst all
> of the airfoils designed the final airfoil selected for the DuckHawk
> is the CS33-18; it allows the aircraft to fly at low lift coefficients
> at high speeds as well as at high lift coefficients at low speeds.
> Winglets were considered but an evaluation of their negatives and
> benefits indicated the DuckHawk would fly better without them when
> real world soaring techniques were considered.
>
> State of the art performance is what Cole is after here, plus safety
> and relative affordability. *The 30:1 aspect ratio and its razor thin
> wings are an obvious clue this is not your generic modern glider.
> Eighty-pound wings will be appreciated by everyone during assembly.
> Eighteen-meter L/D performance with a 15-meter wing span will result
> in lower drag while circling and this plane should climb like a
> bandit.
>
> The ship’s lower mass will give it an induced drag advantage of 29%
> compared to today’s 15m sailplanes at equivalent wing loadings. That
> means better climbing. *Lower wetted area means lower parasitic drag
> and improved high speed running. A wing loading range between 6.25 and
> 10.0 lbs./sq. Ft. will give it ability to adapt to a wide variety of
> soaring conditions - a plane that will get you quickly around the
> course on the tough days and fly faster than anything else out there
> now on really good days.
>
> Before my trip to Windward Performance I was unaware of the complexity
> of the sailplane manufacturing process. *The plugs and molds required
> to produce a sailplane, fill a good sized warehouse even without
> working room around them. *The design and production capabilities of
> this small sailplane operation ...
>
> read more »

SF,

Exactly who at the SSA Soaring Magazine said the subject matter
wasn't suitable for soaring.

Richard
www.craggyareo.com

[noel.wade]

On Feb 28, 9:23*am, wrote:

> Keep in mind that the polar of any glider is a continuous curve and
>
> 9B

While I don't dispute anything you say about the DuckHawk, your
statement about 1 polar curve is not correct.

As you can see from the Johnson Reports over the years, a flapped
aircraft has a different polar at each flap setting (you have a
different camber line and airfoil/wing-shape at each flap setting).

When you see a single polar curve for a flapped aircraft, you're
viewing a "composite" curve that is comprised of the "sweet spots" for
each flap setting.

--Noel
(geek/engineer)

[[email protected]]

On Feb 27, 11:55*pm, Eric Greenwell > wrote:
> wrote:
> > It would seem that the Duckhawk would have more international appeal
> > as a Standard class (15m no flaps) ship - wonder how it would perform
> > without flaps?
>
> It sure wouldn't need that 200 knot Vne, would it? Flaps are essential
> to get the wide speed range that makes the the 200 knot Vne useful. My
> understanding is the airfoil is optimized for climbing and very high
> speed flight.
>
> --
> Eric Greenwell - Washington State, USA
> * Change "netto" to "net" to email me directly
>
> * Updated! "Transponders in Sailplanes"http://tinyurl.com/y739x4
> * * * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more
>
> * "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org

Climb and glide scenario has been going out of favor as optimum
strategy for many years now in favor of extended glide techniques that
optomise cross country speed by minimizing circling and using long
periods of time in the mid to high range to maximize speed made good.
This requires a glider with excellent performance through the whole
speed range which likely will mean that very low speed and or very
high speed are less favored.
Optomising for really high speeds is great for ridge and wave, but not
much use other than final glide in most soaring environments.
It is good to see guys like Gred and Bob giving it a shot.
FWIW
UH

[[email protected]]

On Feb 28, 12:43*pm, wrote:
> On Feb 27, 11:55*pm, Eric Greenwell > wrote:
>
>
>
> > wrote:
> > > It would seem that the Duckhawk would have more international appeal
> > > as a Standard class (15m no flaps) ship - wonder how it would perform
> > > without flaps?
>
> > It sure wouldn't need that 200 knot Vne, would it? Flaps are essential
> > to get the wide speed range that makes the the 200 knot Vne useful. My
> > understanding is the airfoil is optimized for climbing and very high
> > speed flight.
>
> > --
> > Eric Greenwell - Washington State, USA
> > * Change "netto" to "net" to email me directly
>
> > * Updated! "Transponders in Sailplanes"http://tinyurl.com/y739x4
> > * * * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more
>
> > * "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org
>
> Climb and glide scenario has been going out of favor as optimum
> strategy for many years now in favor of extended glide techniques that
> optomise cross country speed by minimizing circling and using long
> periods of time in the mid to high range to maximize speed made good.
> This requires a glider with excellent performance through the whole
> speed range which likely will mean that very low speed and or very
> high speed are less favored.
> Optomising for really high speeds is great for ridge and wave, but not
> much use other than final glide in most soaring environments.
> It is good to see guys like Gred and Bob giving it a shot.
> FWIW
> UH

Good point Hank. Cruise speeds have been coming down, though an
analogous set of principles apply. Still a lighter, smaller airframe
should be able to add a 5-10 knots in cruise speed and you'd think
they could design around that.

9B

9B

[[email protected]]

On Feb 28, 11:15*am, "noel.wade" > wrote:
> On Feb 28, 9:23*am, wrote:
>
> > Keep in mind that the polar of any glider is a continuous curve and
>
> > 9B
>
> While I don't dispute anything you say about the DuckHawk, your
> statement about 1 polar curve is not correct.
>
> As you can see from the Johnson Reports over the years, a flapped
> aircraft has a different polar at each flap setting (you have a
> different camber line and airfoil/wing-shape at each flap setting).
>
> When you see a single polar curve for a flapped aircraft, you're
> viewing a "composite" curve that is comprised of the "sweet spots" for
> each flap setting.
>
> --Noel
> (geek/engineer)

Yup, that's what I meant. There is an optimal flap position/polar for
every alpha. Only the composite curve matters unless you want to fly
with the wrong flap setting.

Andy
(aerospace geek/engineer) ;-p

[Peter[_4_]]

It is absolutely mind boggling how boring and uninformative Soaring magazine
has become. There are hardly any topics anymore on gliders (new or
old).radios, avionics, navigation programs etc...
When I read the article below, I wonder what goes through the mine of
Soaring's editor, what kind of agenda causes them to reject information
like this.No matter the name of the project, whether or not this glider can
live up to the expectation they project, this is EXACTLY the kind of topic
this magazine is lacking , and most of us are looking for! PeterK
"SF" > wrote in message
...
I wrote the following article and submitted it to Soaring for
publication because it was something I was interested in and I thought
others would be too. It was rejected because the subject matter
wasn't suitable for soaring. Greg Cole is doing something
extraordinary at Windward Performance and I feel that Soaring is doing
all of us a disservice by not putting content like this in the
magazine.
******************
My Trip To Windward Performance

At the 2008 SSA convention in Albuquerque, NM I attended Greg Cole’s
presentation on the new 15M sailplane he’s building called the
DuckHawk. The presentation piqued my interest and I managed to
retain the knowledge that the DuckHawk is an American name for
Peregrine Falcon, the fastest moving creature on earth, and that Greg
Cole’s Sailplane factory is in Bend Oregon.

Other details stuck with me too, like an L/D of 52/1. Minimum Sink
is 111 fpm; empty weight is 300 Lbs, and this Hawk has an aspect ratio
of 30.0:1. The 200 Kt. VNE would make for one hot smoking final
glide.

When business took me to Portland, Oregon last Fall, I realized I’d be
fairly close to Bend. A few phone calls got me an appointment with
Greg Cole, president and creative force behind Windward Performance
Ltd, DuckHawk’s creator as well as builders of 11M span SparrowHawk.

Greg Cole has been building and flying his designs since he was a
kid. He has a BSME from the University of North Dakota, and a MSAE
from Notre Dame. He holds a US patent on propeller design. His work
experience includes the McCauley Propeller Company, Columbia Aircraft
Company (chief Engineer), Cirrus Design, Lancair, and Adam Aircraft.
He has made significant Design contributions to several different
aircraft including: the Lancair Legacy, the Lancair Evolution, The
Columbia 300, The Chanute, The A500, and of course the SparrowHawk
which is the only U.S. designed sailplane to hold a world record in 30
years. The Columbia 300 bears mentioning again as it was the first
new design certified by the FAA in 17 years, and it was a full
composite airframe from a new company.

For those of us that live in America’s South, the drive from Portland
to Bend is simply amazing. In South Carolina we drive in one green
tunnel of pine trees after another, and while we have mountains, they
don’t have snow on them in early September like Mount Hood. The drive
down through the high desert is truly beautiful - just don’t try to
pump your own gas. Oregon gas stations are required by state law to be
full service.

The modern sailplane is one truly amazing piece of machinery. They
may look simple but they’re among the most sophisticated aircraft
flying. I learned to fly in a Grob 103. My first single-place glider
was a 1968 Open Cirrus with massive fiberglass spars, fat wings, and
heavy enough to send everyone on the field running the other direction
any time you pull your trailer into the assembly area.

I moved up to a mid-80’s LS6-a, and began teaching students in a
2-33. The historical progression from the 2-33 and its flying barn
door performance, to a first generation glass ship like the Cirrus, a
second generation glass ship like the LS6-a, and a modern glider using
knife like laminar-flow wings is exciting to experience firsthand.
One of my friends sums it up saying “these new planes just do what you
want them to do so much easier, and they do it so much better”.

Improvements in modern sailplane performance have been driven by
advances in materials, a better understanding of how to design
aerodynamic structures with these materials, computer modeling, and
leaps in understanding aerodynamic principles. Most modern sailplanes,
with the exception of Windward Performance’s aircraft, are built with
a wet, room temperature cured, epoxy resin lay up using glass, carbon,
or Kevlar fiber reinforcement. The reinforcing cloth is laid into the
mold by hand and the epoxy squeegeed, or painted on. This type of
construction process was quite an advance over previous wood and metal
construction and quite a bit better than “fiberglass” or polyester
resins or even the vinyl ester resins but still imposes several
limitations on how strong aircraft parts may be made.

When the resins cure at room temperature there is fairly short
amount of “out-time” – the number of minutes workers have to craft the
part before the resin’s curing process begins. Complicated multi-
layer layups have to be done quickly. Yet fiber orientation and
wetout are important in critical aircraft applications. As a result
room-temperature resin application often means a heavier composite
structure to maintain structural safety. The room temperature curing
of resins, causes the finished part to lose structural integrity
rapidly at temperatures over 140 F, which is why modern composite
sailplanes are painted white. If they were painted black or even red
they would heat up under sunlight and loose structural integrity.

Thus Cole’s Windward Performance is the only sailplane manufacturer
I’m aware of to use sophisticated prepreg oven-cured carbon fiber
construction. Prepreg carbon fiber is produced in a factory by
sandwiching a carbon fiber cloth between two epoxy resin sheets, the
sandwich is then run this between high-pressure rollers. The high
pressure insures an even and complete epoxy coating of the fabric with
the ability to very precisely control the ratio of resin to fabric.
This allows the composite’s weight to remain low but optimized for
strength with very tight tolerances. Once the fabric is epoxy coated
it is refrigerated for storage and transport, greatly retarding the
start of the curing process.

Since the resin does not cure at room temperatures there is much more
out-time in which to lay up the prepreg material in, say, a wing-mold
while avoiding mistakes from rushing. There’ more time for forming
complicated multi-layer configurations.

In Windward’s aircraft, the prepreg layup is vacuum-bagged to ensure
all air is squeezed out of the layup and the entire assembly goes into
an oven to cure at high temperatures. The benefits of all this are
lighter, far stronger and stiffer composites with a much larger
temperature operating range than conventional wet layup composites
afford.
Given these advantages, and given Greg Cole’s expertise and obviously
high standards of craftsmanship, it became clear why Windward
Performance uses prepregs, and why they result in the Duck Hawk’s
performance advantages.

A winning 15M racing sailplane moves around the course in the least
amount of time with the highest average cross country speed. The key
to obtaining that is, naturally, minimizing the time you go slow.
Climbing well and going fast between thermals sounds easy, but
mastering this simple concept is far from easy. Most of us with
modest skills in this area could use all the help we can get from the
aircraft.

The modeling of average cross country speeds with different
atmospheric conditions allowed performance simulations of different
design iterations to be run and small improvements or losses to be
determined. The accuracy of modeling new designs was, for Cole,
validated by modeling current designs with known performance
characteristics.

Designs that can be made light with small wing areas offer improved
performance over conventional designs especially in tough conditions.
Tough conditions – small thermals, weak lift, headwinds, etc. - seem
to have a far greater negative impact on my contest results than do
the positives of favorable conditions.

Cole’s calculations show soaring with the ability to fly well with low
lift coefficients can also give the ability to go fast at relatively
low wing loadings, meaning faster average cross country speeds. The
results of the modeling process indicated an optimum with a wing area
of 80 SQFT, and a wing loading of 8.75 LBS/SQFT.

Determining the optimum airfoil also benefits from Cole’s computer
modeling process. Structural constraints start as the wing area drops
below 90 square feet, and wing volume available for ballast drops
rapidly as well. As wing area decreases, the Reynolds number goes
down and achieving low drag at high and low lift coefficients becomes
more and more difficult.

Good stalling behavior is another factor Cole considered. Amongst all
of the airfoils designed the final airfoil selected for the DuckHawk
is the CS33-18; it allows the aircraft to fly at low lift coefficients
at high speeds as well as at high lift coefficients at low speeds.
Winglets were considered but an evaluation of their negatives and
benefits indicated the DuckHawk would fly better without them when
real world soaring techniques were considered.

State of the art performance is what Cole is after here, plus safety
and relative affordability. The 30:1 aspect ratio and its razor thin
wings are an obvious clue this is not your generic modern glider.
Eighty-pound wings will be appreciated by everyone during assembly.
Eighteen-meter L/D performance with a 15-meter wing span will result
in lower drag while circling and this plane should climb like a
bandit.

The ship’s lower mass will give it an induced drag advantage of 29%
compared to today’s 15m sailplanes at equivalent wing loadings. That
means better climbing. Lower wetted area means lower parasitic drag
and improved high speed running. A wing loading range between 6.25 and
10.0 lbs./sq. Ft. will give it ability to adapt to a wide variety of
soaring conditions - a plane that will get you quickly around the
course on the tough days and fly faster than anything else out there
now on really good days.

Before my trip to Windward Performance I was unaware of the complexity
of the sailplane manufacturing process. The plugs and molds required
to produce a sailplane, fill a good sized warehouse even without
working room around them. The design and production capabilities of
this small sailplane operation were a very pleasant surprise. This is
a small operation but it possesses world class design talent and state
of the art manufacturing processes. While I love my German sailplane
and fully recognize the abilities of the established sailplane
manufacturing companies, I find myself rooting for the underdog home
team in this case.

The first DuckHawk should take to the air summer 2009, and I look
forward to seeing the finished product. In addition to the DuckHawk
Windward has a few other products currently in the works. They are
currently building the Perlan sailplane designed to take two people to
90,000 FT. The Windward Goshawk, an electric aircraft is also being
built. Advances in composites are ushering in a new era in aircraft
innovation and thanks to Greg Cole’s love of soaring we get be benefit
from his creativity, with an exciting new American sailplane.

[Eric Greenwell]

Peter wrote:
> It is absolutely mind boggling how boring and uninformative Soaring magazine
> has become. There are hardly any topics anymore on gliders (new or
> old).radios, avionics, navigation programs etc...
> When I read the article below, I wonder what goes through the mine of
> Soaring's editor, what kind of agenda causes them to reject information
> like this.No matter the name of the project, whether or not this glider can
> live up to the expectation they project, this is EXACTLY the kind of topic
> this magazine is lacking , and most of us are looking for! PeterK

I'd like to suggest it wasn't the DuckHawk subject matter that led to
the rejection. The fact this thread has gone on so long with a number of
questions about the design of the DuckHawk indicates it the article by
"SF" is incomplete at best.

A month ago, I had a brief 15 minute discussion with Greg Cole that
covered a number of important aspects about the DuckHawk's goals and his
approach to solving them, most of which are missing from the article.
Since that wasn't our main topic, the brevity and the lack of notes
means I can't add a lot to the conversation here.

It's still a rough draft in my opinion, and I hope he got some useful
guidance from the Soaring magazine editor or contributors (like Bill
Collum) about filling in the holes. Perhaps culling the best from the
article until it's short enough to fit into the Soaring Mail or Soaring
News departments would be a good way to pass on what he learned.


> "SF" > wrote in message
> ...
> I wrote the following article and submitted it to Soaring for
> publication because it was something I was interested in and I thought
> others would be too. It was rejected because the subject matter
> wasn't suitable for soaring.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

[kestrel19]

On Feb 28, 8:29*pm, Eric Greenwell > wrote:
> Peter wrote:
> > It is absolutely mind boggling how boring and uninformative Soaring magazine
> > has become. There are hardly any topics anymore on gliders (new or
> > old).radios, avionics, navigation programs etc...
> > When I read the article below, I wonder what goes through the mine of
> > Soaring's editor, what kind of agenda *causes them to reject information
> > like this.No matter the name of the project, whether or not this glider can
> > live up to the expectation they project, this is EXACTLY the kind of topic
> > this magazine is lacking , and most of us are looking for! PeterK
>
> I'd like to suggest it wasn't the DuckHawk subject matter that led to
> the rejection. The fact this thread has gone on so long with a number of
> questions about the design of the DuckHawk indicates it the article by
> "SF" is incomplete at best.
>
> A month ago, I had a brief 15 minute discussion with Greg Cole that
> covered a number of important aspects about the DuckHawk's goals and his
> approach to solving them, most of which are missing from the article.
> Since that wasn't our main topic, the brevity and the lack of notes
> means I can't add a lot to the conversation here.
>
> It's still a rough draft in my opinion, and I hope he got some useful
> guidance from the Soaring magazine editor or contributors (like Bill
> Collum) about filling in the holes. Perhaps culling the best from the
> article until it's short enough to fit into the Soaring Mail or Soaring
> News departments would be a good way to pass on what he learned.
>
> > "SF" > wrote in message
> ....
> > I wrote the following article and submitted it to Soaring for
> > publication because it was something I was interested in and I thought
> > others would be too. *It was rejected because the subject matter
> > wasn't suitable for soaring.
>
> --
> Eric Greenwell - Washington State, USA
> * Change "netto" to "net" to email me directly
>
> * Updated! "Transponders in Sailplanes"http://tinyurl.com/y739x4
> * * * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more
>
> * "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org

Please note that the Soaring editor has an advisory group, which has
been under development for about a year. Currently it's listed as the
Editorial Advisory Group, but my understanding from the Chicago SSA
board meeting was that it was more properly to be a Technical Advisory
Group (and so renamed I thought), not involved in editing submissions
in any way. I don't know if all articles are reviewed by the relevant
contact. If you have any questions, this group has a chair person.
The group reports to SSA director John Dezzutti.

http://www.ssa.org/members/governance/VolunteersDetail.asp?group=70

HTH,

Frank Whiteley

[[email protected]]

On Feb 28, 10:54*pm, kestrel19 > wrote:
> On Feb 28, 8:29*pm, Eric Greenwell > wrote:
>
>
>
>
>
> > Peter wrote:
> > > It is absolutely mind boggling how boring and uninformative Soaring magazine
> > > has become. There are hardly any topics anymore on gliders (new or
> > > old).radios, avionics, navigation programs etc...
> > > When I read the article below, I wonder what goes through the mine of
> > > Soaring's editor, what kind of agenda *causes them to reject information
> > > like this.No matter the name of the project, whether or not this glider can
> > > live up to the expectation they project, this is EXACTLY the kind of topic
> > > this magazine is lacking , and most of us are looking for! PeterK
>
> > I'd like to suggest it wasn't the DuckHawk subject matter that led to
> > the rejection. The fact this thread has gone on so long with a number of
> > questions about the design of the DuckHawk indicates it the article by
> > "SF" is incomplete at best.
>
> > A month ago, I had a brief 15 minute discussion with Greg Cole that
> > covered a number of important aspects about the DuckHawk's goals and his
> > approach to solving them, most of which are missing from the article.
> > Since that wasn't our main topic, the brevity and the lack of notes
> > means I can't add a lot to the conversation here.
>
> > It's still a rough draft in my opinion, and I hope he got some useful
> > guidance from the Soaring magazine editor or contributors (like Bill
> > Collum) about filling in the holes. Perhaps culling the best from the
> > article until it's short enough to fit into the Soaring Mail or Soaring
> > News departments would be a good way to pass on what he learned.
>
> > > "SF" > wrote in message
> > ....
> > > I wrote the following article and submitted it to Soaring for
> > > publication because it was something I was interested in and I thought
> > > others would be too. *It was rejected because the subject matter
> > > wasn't suitable for soaring.
>
> > --
> > Eric Greenwell - Washington State, USA
> > * Change "netto" to "net" to email me directly
>
> > * Updated! "Transponders in Sailplanes"http://tinyurl.com/y739x4
> > * * * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more
>
> > * "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org
>
> Please note that the Soaring editor has an advisory group, which has
> been under development for about a year. *Currently it's listed as the
> Editorial Advisory Group, but my understanding from the Chicago SSA
> board meeting was that it was more properly to be a Technical Advisory
> Group (and so renamed I thought), not involved in editing submissions
> in any way. *I don't know if all articles are reviewed by the relevant
> contact. *If you have any questions, this group has a chair person.
> The group reports to SSA director John Dezzutti.
>
> http://www.ssa.org/members/governance/VolunteersDetail.asp?group=70
>
> HTH,
>
> Frank Whiteley- Hide quoted text -
>
> - Show quoted text -

EAG-or whatever name you wish to put on it, does serve to help the
editor to ensure that articles published in Soaring are technically
correct, be that related to FAR's, maintenance, training,
aerodynamics, whatever. Chuch recognizes that he doesn't know it all
and is striving to use his resources to produce a good product whuich
we can all enjoy and learn from. I serve in this group along with a
dozen or so people knowledgable in most aspects of the sport.
Having read what has been posted here, I would have suggested that the
author go to Greg and have Greg do some additions and clarifications
to it to ensure that the proposed article is technically correct and
get some interesting photos and illustrations to show some of the
points described.
Having done this, I am confident that Chuck and the EAG would find
this article suitable for publishing is Soaring magazine.
UH

[nurflugel]

While lurking on this elist for some years, we've been able to pick up
a few leads on items for publication in RC Soaring Digest <http://
www.rcsoaringdigest.com>. RCSD is a monthly ezine devoted to all
aspects of RC soaring. RCSD is distributed as a PDF at no charge and
is read by thousands of modellers around the world.

A large number of readers are involved in building and flying scale
models, whether on the slope, winch-launched over flat land, or
aerotowed. RCSD publishes walk-arounds of full size gilders for the
purpose of documentation for these modelers. Both the SparrowHawk and
the DuckHawk are attractive planforms for modeling, and this article
describes design and manufacturing processes nearly identical to that
used by the radio controlled model sailplane industry and by a growing
number of individuals.

We would very much like to publish this article in a future issue of
RCSD, augmented with illustrations and data from the Windward
Performance Ltd. web site.

The deadline for the April issue is March 15. Our contact information
can be found on the RCSD home page.