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Performance Characteristics of the PD Sabre2 Sabre2
Flight Characteristics 1.
Introduction The
Sabre2 from Performance Designs is a slightly tapered, zero-porosity nine cell
canopy. Like
the original PD Sabre, the Sabre2 is designed to be fun to fly, easy to land,
and to be a great general–purpose skydiving canopy.
This is not just a modified Sabre, though.
The Sabre2 is a totally new design, and takes full advantage
of the research and technological advancements we have achieved in the decade
that has passed since we released the original Sabre. In
this document, we will compare the performance characteristics of the Sabre2 to
the original Sabre, since it remains a popular canopy.
We will also compare some characteristics to the PD Spectre, another
popular general-purpose canopy. A
Note on Comparing Canopies:
When comparing two different canopy designs, such as the original Sabre
and the Sabre2, an accurate comparison can only be made if the canopies are the
same size, they are flown under similar conditions, and they are flown by the
same jumper, or by two jumpers of very similar size and weight.
Comparing a 150 Sabre2 to a 170 square foot canopy, for example, would
not yield an accurate comparison. The
way canopies are “set up” can also affect a comparison.
Two identical canopies will perform differently if one has the toggles
attached at the location specified by the factory, but the other has had the
steering lines shortened a few inches. If
one canopy has a collapsible pilot chute and the other does not, this will also
make a significant difference. There
may also be a difference between a canopy with new lines, and one that has
several hundred jumps on the line set. 2.
Openings To
describe the openings, we need to agree on some common terms.
The first part of the opening you feel, when the canopy first reaches the
end of the lines, is the snatch force.
The second phase of the opening, when the canopy is overhead but the
slider is still all the way up, is called the snivel.
The third stage, when the slider travels down the lines and the cells
finally pressurize, is called the inflation. Overall,
the openings on the Sabre2 are quite comfortable.
The Sabre2 has about the same snatch force as a Spectre or the original
Sabre. It will generally snivel
longer than a Sabre, but not quite as long as a Spectre.
The inflation speed is similar to the Spectre.
The
Sabre2 is also similar to the Spectre in that it is fairly forgiving of packing
technique, body position, and the airspeed at which it is deployed.
We had consistently good openings while testing the Sabre2 using a
variety of packing methods, including our normal factory PRO pack, a neat side
pack, and some other pack jobs that probably were not wise to try. You
will get the best results, however, by using the packing method we recommend,
and by deploying at a reasonable airspeed while in a good body position.
As with any canopy, a correctly positioned slider, proper line stows, and
a correctly sized pilot chute are required to ensure consistently soft openings.
See our information sheet entitled “Solving Deployment Problems” for
more information. 3.
Flight Characteristics Although
the overall flight characteristics of the Sabre2 are similar to the original
Sabre, there are a few noticeable differences: Straight
Flight at full Glide: The
Sabre2 and the original Sabre both fly at about the same airspeed, but the glide
angle of the Sabre2 is a bit flatter. You
may notice the Sabre2 gives you better penetration when flying into the wind,
and carries you farther when flying with the wind at your back. Straight
Flight in Brakes: The
Sabre2 has a lower rate of descent in brakes than the original Sabre.
This will be useful if you are returning from a long spot with the wind
at your back, and use your brakes to “float” farther.
It will also be useful if you like to fly in brakes for a while after
opening, to let other canopies land first. Toggle
Turns from Full Glide:
The Sabre2 is more responsive than the original Sabre, but not radically
different. Less toggle input is
required to start a turn on the Sabre2, and toggle pressure is generally lighter
than the original Sabre. Like the
Spectre, the Sabre2 will lose slightly more altitude in a turn than the original
Sabre. Toggle
Turns in Brakes (Flat Turns):
Flat turns are an important technique to learn on any canopy.
By pulling the toggles half way down, then slowly raising or lowering one
toggle to start a turn, you will lose much less altitude than by making a turn
from full glide. The Sabre2 is
quite responsive in braked flight, making flat turns very effective on this
canopy. Front
Riser Turns:
Like the Spectre, the Sabre2 has light front riser pressure.
Even larger sizes of the Sabre2 respond fairly well to front riser input.
As with most canopies, if the control lines are too short the Sabre2 may
“hobble” when the front risers are pulled.
A canopy’s control lines normally become shorter after several hundred
jumps, or can be made too short by attaching the steering toggles too close to
the brake loop. Stall
Characteristics:
As with the Spectre and the original Sabre, you may find that you can
pull the toggles all the way down to full arm extension without stalling the
Sabre2, especially if you are jumping a larger one.
It’s important to remember that you do not have to be able to stall
your canopy in order to land it correctly.
Technically, a stall means the canopy has dramatically reduced its lift
and increased its rate of descent. A
stalled canopy is not really “flying” any longer.
If you want a soft landing, you really want your canopy to keep creating
lift and maintain a low rate of descent until your feet are on the ground.
If you adjust your steering toggles so that your canopy is easier to
stall, it may actually become more difficult to land softly. The
Sabre2 will reach a fairly low airspeed before stalling.
As with many canopies, it’s not unusual to experience some end cell
closure when recovering from a full stall.
After recovering from a stall, bringing the toggles back down to between
½ and ¾ brakes and holding them there for a moment will help the end cells
re-inflate more quickly. Landings:
Like the original Sabre, the Sabre2 is an easy canopy to land.
When a proper flare technique is used, the Sabre2 generates more lift at
low airspeed, which allows for even slower touchdown speeds and softer landings.
And like the original Sabre, the Sabre2 may still give you a decent
landing even if your flare is less than perfect, as long as you are jumping one
that is a reasonable size. Aggressive
Approaches (High-Speed Approaches):
As we mentioned above, the Sabre2 loses slightly more altitude in a turn
than the original Sabre and the Spectre. By
comparison, the PD Stiletto pulls out of a dive relatively quickly.
As with most canopies, smaller sizes dive more in turns than larger ones. It
is important to consider differences like these when making an aggressive,
turning approach on a canopy that is new to you.
Even if you have made hundreds or thousands of these approaches, it is
best to be cautious when trying a new type of canopy or a smaller size than you
are accustomed to. 4.
Canopy Sizing The
chart below shows our suggested weight limits for the Sabre2.
We provide this information with each of our canopies to help you choose
the correct canopy size for your weight and experience level.
It is important to understand what the information really means so you
can use these charts correctly. Exit
weight is your body weight plus the weight of your clothing, rig, main and
reserve canopies, and anything else you will be wearing when you exit the
aircraft. The average jumper’s
exit weight is about 20 to 25 lbs. more than his or her body weight. There
are various exit weights listed on the chart below, divided into several
experience categories. It’s
important to note that these are maximum weight limits.
For example, the maximum exit weight listed under “Novice” for a 170
Sabre2 is 153 lbs. This means we
feel the 170 is appropriate for a novice jumper with an exit weight of 153 lbs. or
less. It does not mean
you must weigh 153 lbs. to make this canopy perform correctly.
In fact, a much lighter jumper might be perfectly happy flying this
canopy. The canopy will have a
slower forward speed and lower rate of descent when flown by a lighter jumper,
and is likely to be more forgiving and easier to land.
These may be exactly the characteristics this jumper wants from a canopy! Of
course, a light jumper on a large canopy may be affected more by high winds.
This is why the minimum exit weight “varies with weather and
landing conditions” (VLC). If the
winds are light, a 150 lb. jumper might enjoy flying a 230 square-foot canopy,
but this would not be a good idea if the winds were very strong and gusty. The
chart below can help you determine the canopy sizes that might be appropriate
for you, but we don’t recommend making your decision based solely on this
information. Just as you need to
try on a pair of shoes to see if they actually fit, you really won’t know how
a particular size canopy will fly until you have actually jumped it.
When purchasing a canopy, it’s best to choose a model and size that you
know from experience will provide the performance you want. If
you plan to jump a canopy that is smaller than any you have used before, your
exit weight should be within the “Student” or “Novice” category for that
canopy, and you should be trained to use the canopy by a qualified instructor.
Or, you should have at least 50 jumps on a canopy that is no more than
15% larger (approximately one size), and be able to consistently make soft,
accurate landings with that larger canopy.
VLC
= Varies with weather and landing conditions N/S
= Not Suggested **
= Although these canopies have been used successfully with students, Performance
Designs has other models which may be more appropriate. PG.
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