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The chart
below is very revealing. The more you look, the
more you'll understand the advantages and trade offs of these
leading wings. We've also included a couple of earlier designs,
the Silex and Power Altas, to show how techology has improved over
the past 10 years.
See below for an explanation of the chart and
analysis of the gliders. |
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Glider
Name
|
Altas |
Silex |
ParaToys |
Bolero3 |
Escape
|
Kinetik |
Rush |
Eden3 |
Spice |
Revolutn |
ReAction |
ActionGT |
Alternate
Names
|
Power
Altas |
|
Muse |
|
Sting |
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Year
Introduced |
1997 |
1998 |
2005 |
2006 |
2002 |
2003 |
2005 |
2005 |
2005 |
2005 |
2005 |
2006 |
Aspect ratio
flat |
4.7 |
4.8 |
4.7 |
4.8 |
5.0 |
5.1 |
5.2 |
5.3 |
5.8 |
5.6 |
5.4 |
5.9 |
Aspect ratio
projected |
3.9 |
3.9 |
4.0 |
3.7 |
4.2 |
4.0 |
3.7 |
4.7 |
5.1 |
4.6 |
4.2 |
4.8 |
Number
of
Cells |
35 |
48 |
41 |
38 |
46 |
52 |
46 |
52 |
63 |
49 |
65 |
66 |
Minimum
Sink
m/sec |
1.2 |
1.3 |
1.2 |
1.2 |
1.2 |
1.1 |
1.1 |
1.2 |
1.1 |
1.1 |
1.1 |
1.1 |
Glide
Ratio
(Lift/Drag)
|
7.1 |
7.3 |
7.8 |
7.8 |
8.0 |
8.1 |
8.3 |
8.3 |
8.5 |
8.1 |
8.5 |
9.1 |
Max
Speed
kph |
42 |
50 |
47 |
45 |
45 |
48 |
50 |
50 |
60 |
56 |
60 |
58 |
DHV
Certificaion |
1-2 |
|
1 |
1 |
1-2 |
1-2 |
1-2 |
1-2 |
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CEN/AFNOR
Certificaion |
Stand |
|
Stand |
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PPG |
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Perfm |
|
Perfm |
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DULV
Certificaion |
|
2 |
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1 |
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What does it all mean... |
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In this article, you
will learn about what factors effect wing performance. This knowledge
will help you choose a wing today, and lend perspective on how
you may transition to different wings in the future.
Source of the data
All the data in the chart is from an independent source that collects specs
on every glider ever made. You can visit the site yourself at Para2000.org.
These specs are accurate and unbiased. Note that because the Speed Demon
was just introduced, specs are not yet available.
Alternate Wing Names
Some gliders are copies of other gliders or have simply been renamed. This
can be confusing so we added the Alternate Names data.
Year Introduced
This is the year that the glider became available to the public. This data
is important for two reasons.
Over the years, paraglider technology improved has improved dramatically.
New materials and design techniques have improved wing performance
while increasing safety. Therefore, when comparing gliders, in
order to compare apples to apples, it is important to compare gliders
designed no more than a few years apart.
Most importantly, a few older designs are still on the market
today, and although they are in new condition, they are not the
latest technology. These gliders have less performance and safety
than new designs. The Power Altas and the Silex are examples of
old technology that are still being sold today. There are others.
Before buying a wing, check Para2000.org to
see what year the paraglider was introduced. |
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Aspect Ratio
Aspect Ratio is the ratio of the wing span
divided by the cord of the wing. So if the wing span
is 30 feet and the cord is 6 feet, then the aspect ratio is 5.
Aspect Ratio effects glider performance and characteristics more
than any other factor. As aspect ratio increases, gliders become
more efficient, have a faster top speed, and are more responsive
in flight and on the ground. The trade off is that as
aspect ratio increases, gliders become more prone to collapse in
turbulence, and recovery is not as smooth as with lower aspect
ratio gliders. Higher aspect ratio gliders also require a more
sensative touch on ground and in the air, making them more challenging
for beginners.
Aspect Ratio: Flat versus Projected
Flat Aspect ratio is measured when the wing is laying flat. Projected
aspect ratio is equivelent to the wing's shadow on the ground
when inflated. The relivance of flat versus projected aspect
ratio is subtle, and too long to cover here. We'll
go over this interesting relationship in more depth in a future
article.
Number of Cells
As with aspect ratio, increasing the number of cells in a paraglider
increases the efficiency and speed of a paraglider. And just
like aspect ratio, the trade off with more cells is a
greater tendency to collapse and a more complex recovery.
It is important to note that over the
years, improvements in technology have allowed us to increase both
aspect ratio and the number cells while actually decreasing the
likelyhood of a collapse and improving the recovery characteristics.
Newer designs are safer and better performers. That's why it is
important to compare wings designed around the same time.
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Minimum
Sink, Glide Ratio
The two most common indicators of glider efficiency are minimum sink rate and
glide ratio. Minimum sink is the glider's slowest rate of descent, with the
power off. Glide ratio is the gliders best glide angle with power off. For
example, a glide ratio of 8 means the glider will progress 800 feet forward
for every 100 feet it descends.
The glide ratios in the chart are
based on flying with a clean paraglider harness. Because paramotors have
a lot more drag, count on a PPG glide of around 15% less.
Efficient gliders have longer range, better endurance, and usually
more responsive handling in the air and on the ground. Efficient
gliders can be flown at higher wing loadings, increasing top speed
and stability in turbulence.
As stated above, efficiency is increased by increasing aspect
ratio and the number of cells. Looking at the chart, this trend
is clear. It also follows that efficient gliders are more prone
to collapse and have a more complicated recovery process.
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Max Speed
The max speed refers to the maximum airspeed a glider can achieve. Flying at
max speed almost always involves engaging trimmers or the speed bar or
both. Trimmers and speed bar enable you to change the length of the risers
in flight, decreasing your angle of attack, thereby increasing your airspeed.
For many pilots, speed is not important. Low and slow their preference,
and this is especially true for beginners. Faster gliders are typically
more desirable for pilots who like to fly long distances.
If speed is important to you, there are
a few things to consider. First of all, at higher speeds, reflex
gliders are safer, to a point. Without getting too technical,
the faster you fly a paraglider, the more likely it is that turbulence
could cause the glider to collapse. Reflex gliders resist collapse
at higher speeds by loading the front of the glider and with
a "tail" effect that
furthers stabilizes the front of the glider. However, if a reflex
glider does collapse, the recovery will be more dramatic, requiring
more altitude, more time, and more pilot input. All in all, reflex
gliders are the wave of the future. They are increasing in popularity
for new pilots as well as experienced pilots.
Another way to increase speed is to fly a smaller glider. Of course
the trade off is that take offs and landings will be faster. However,
if the wing is efficient, like the Eden
3 for example, then the glider will have more lift enabling
the glider to slow down for easier take offs and landings. |
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Certification
The certification process measures the
paraglider's ability to avoid and recover from abnormal flight
modes such as a collapse or spin. The pilot to the left has intentionally
entered a front horseshoe configuration. Consider the certification
a metric for safety.
The only acceptable certification ratings for
a beginner pilots are DHV 1, DHV 1-2, AFNOR Standard, and DULV
1. Some gliders have no certification. Beginners should avoid these
gliders. The exception is the Revolution. This glider, though not
cerfied, has a very good track record with new and intermediate
pilots.
Note that DHV 1-2 rated gliders are typically
intermediate level and more efficient than the DHV 1 rated beginner
gliders. Both categories are safe for beginners. |
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Old Technology
Now that you are familiar with glider characteristics, compare the Power Altas
with the new leading gliders.
First compare the Power Altas with the ParaToys/Muse
and Bolero. Notice that although the Altas has a DHV 1-2 intermediate
rating, it has less performance than the DHV 1 rated ParaToys/Muse
and Bolero. The newer gliders have increased performance and
safety. Handling of the new gliders has also improved dramatically.
The Silex, introduced in 1998, was for a long
time one of the most popular wings for powered paragliding. Compare
the Silex with the Rush and the Eden
3. The Silex has a DULV
rating of 2, not as safe as the DHV 1-2 rating for the Rush and
the Eden 3. Yet all these gliders and the same top speed, and
the Rush and Eden 3 are far more efficient.
New Technology
With this latest crop of new
gliders,
it's really hard to go wrong. Follow the guidelines in this article
and the Wing Buyer's
Guide. Then call us and we'll help you confirm your choice. |
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