Dacron® , Mylar® and General Sailcloth Information

With respect to sail materials, the term Dacron® is commonly used to refer to a woven cloth made of polyester fibers. More correctly, Dacron® is a registered trademark of DuPont, and refers specifically to a DuPont developed polyester fiber.

In a similar manner, with respect to sail materials, the term Mylar® is commonly used to refer to a polyester film, and, again, Mylar® is a registered trademark of DuPont, and refers specifically to a DuPont developed polyester film.

There are basically two types of sail materials used in hang glider sails - woven polyester fabrics and composite laminated fabrics that use some combination of polyester film and polyester reinforcing fibers. Wills Wing uses premium fabrics made by Dimension-Polyant, widely recognized as the leading sail cloth manufacturer in the world.

V170 4.0 Ounce Woven Polyester Fabric

This is the most basic, commonly used sailcloth. It forms essentially the entire sail on gliders like the Falcon and the Eagle, and is typically used in the bottom surface and mid-chord top surface of other model gliders. It comes in white and in colors, and it is a very tight weave of small diameter polyester fibers, which is subsequently "stabilized" by the hot-press impregnation of a polyester resin. The purpose of the resin impregnation is to provide "dimensional stability" which is the resistance to distortion or stretch of the material along the "bias" - in other words, at some angle to the two perpendicular directions of the threads that form the weave. This resistance to bias stretch is important in maintaining the aerodynamic shape originally designed into the sail, when the sail is placed under varying loads. The material is relatively light in weight, moderately elastic, and has good durability. It provides the best combination of light weight and durability in a sail with the best overall handling qualities.

Try the Glider Color Selector to see colors and sail patterns.

205MT and 240MT

These are two heavier woven fabrics, which utilize a ripstop pattern of larger diameter fibers woven into the regular cloth. These materials come in white only, and are typically used on the trailing edge of higher performance gliders, or other gliders where the trailing edge is subject to higher loads. 205 MT, which has a weight of 4.9 ounces per sailmaker's yard, is the standard trailing edge fabric on the T2and U2. 240 MT, which has a weight of 5.7 ounces per sailmaker's yard, is the standard trailing edge fabric on the Falcon Tandem. These fabrics provide greater durability and increased resistance to stretch under heavier loads, allowing for better control of spanwise twist on high performance gliders.

HYDRA-NET® 200

Hydra-net® is a trademark of Dimension-Polyant, and refers to a tightly woven high tenacity fabric with an integrated ripstop pattern of Spectra® fibers. The use of these Spectra® reinforcing fibers in a relatively light-weight cloth provides the structural performance and durability of a heavier cloth with the superior handling of a lighter weight material. Hydra-net 200 comes in white only, and is an upgrade option for the trailing edge panel or leading edge panel on the T2and U2.

PX & PM Polyester X-Ply Laminates

These are two types (with several subtypes) of what are commonly called "Mylar®" sailcloth. They are not available in colors, and will be either "mostly clear" or white depending on cloth construction. Laminated sail materials using polyester film have been used for many years in hang glider sails. The original inspiration for the use of these fabrics was an attempt to achieve superior performance by using a lower stretch material that was still relatively light in weight. In high performance hang gliders, limiting spanwise twist is a key component of performance, and twist is generally controlled by sail tension. The disadvantages of the polyester film fabrics have been that the reduced elasticity under load has generally resulted in "stiffer," less responsive handling qualities, and that the polyester laminated fabrics have been, historically, not as durable or long lasting as woven fabrics. The current generation of laminated fabrics are vastly improved over those of even ten years ago, however it is still generally the case that a premium woven fabric will outlast even the best laminated materials.

The PM Laminates are a three layer laminate in which two outer layers of polyester film sandwich an inner layer of scrim (open net of polyester fibers).

The PX Laminates are a four layer laminate in which a 6 degree X-ply layer of black polyester yarns is added in between the polyester film layers.

PX10

PX10T, Black Xply® version with taffeta backing, shown for clarity. The laminates without taffeta are somewhat transparent, and the 'PM' types do not have the Xply layer.

Polyester X-Ply® Laminate construction. The PM series cloths are made without the X-Ply layer, and the PM--T cloths feature a layer of Taffeta fabric, for durability, ouside of and behind the film sandwich.

In either type, a thin, lightweight layer of taffeta may be bonded to one side, on the outside of the film sandwich, for added durability. These variants are designated with the addition of a "T," as in PM05T, or PX10T.

UVM10T and UVM10T WHT- NEW!

UVM10T Original

UVM10T White

New UV Resistant Mylar Sail Material Now Available

There is a new sail material available for T2’s (entire top surface or just panel #1) and U2’s and Sport 2’s (panel #1 only) that can be used in place of the normal PX10T Mylar sail cloth. The new “UVM10T” material is a specially treated Mylar composite, similar in structural properties to the standard PX10T Mylar material, but with a high degree of UV protection built in to the outer film via a high-pressure infusion process. This special treatment stops 90% of UV transmission through the top layer. There is also an additional UV barrier between the top surface film and the substrate. The result is a sail material expected to last a full 30% longer, at a minimum, than conventional Mylar sail material. Note that although the original UVM10T material is gray in color, this is not simply a cosmetically “smoked” conventional Mylar material. The specially infused film used in the making of this material is 20 times more expensive than the normal film used in Mylar sailcloth.

01A-A31 – UVM10T Upgrade P1 Only
01A-A32 – UVM10T Upgrade Complete Top Surface

Initially, the UVM10T material was only available in the gray color. It has now become available in white as well. The white UVM material enhances glider visibility and can be selected for the leading edge (#1) panel on T2’s, U2’s and Sport 2’s, and the trailing edge panel (#4) on T2’s with full mylar top surface – see the application chart for details. The midchord #3 panel on full mylar T2’s uses a lighter weight material, which is still only available in the gray color, if the UVM material is selected.

T2 with UVM10T WHT #1 and #4 panel, UVM05T #3 panel

Falcons and Sport 2s

Falcon and Sport 2 sails (excluding the Falcon Tandem) are normally made entirely with V170 4.0 ounce w fabric, for light weight, good durability, and optimum handling. The only sail cloth material option in the Falcon line is the option for PX05 in the #3 and #4 panels on a Falcon 3 170 or Falcon 3 195. In the Sport 2 line, as of January 2008, you may select 205 MT or Hydranet 200 in either the top surface leading edge panel (#1) or trailing edge panel (#4) or both. You may also select either PX10T or UVM10T in the top surface leading edge panel (#1). The upgrade from the normal V170 to 205 MT or PX10T costs $75 per panel, and an additional upgrade to either premium fabric (Hydranet or UVM10T) adds an additional $75 per panel upgraded. For example, an upgrade to UVM10T on panel #1 and Hydranet on Panel #4, would add $300 to the total price. With regard to color choice options, the top surface leading edge (#1) and bottom surface (#5 on the Falcon, #5 and #6 on the Sport 2) are normally made with either colored or white V170 material, and you can select your own colors for these panels when you elect the "Customer choice of colors" upgrade. If you upgrade to any of the premium cloth options, there are no color choices for those panels.

Falcon Tandem

All of the above paragraph applies to the Falcon Tandem except that the #4 trailing edge panel is always made from 240 MT and therefore is only available in white.

T2s and U2s and Sport 2s

The T2 and U2 come standard with PX10T in the top surface leading edge panel, 205 MT in the trailing edge panel, and V170 4.0 ounce in the top surface midchord (#3) and bottom surface panels (#5, #6). The Sport 2 comes standard with V170 4.0 ounce in all panels except the trailing edge (#4) which is now made with IU200 White (slightly heavier woven material). The bottom surface panels are normally available for color choice when you elect the "Customer choice of colors" upgrade. It is also possible to have color in the top surface midchord (#3) panel, for an additional charge. PX10T, UVM, Hydranet or 205 MT can be ordered as extra cost options on certain panels – see the application chart for details.

Hydra-Net 200 is an extra cost upgrade option for the trailing edge panel of either a T2 or U2 or Sport 2. Hydra-Net 200 and 205 MT are, in our experience, essentially equivalent with respect to performance and handling when used in the trailing edge panel of the U2. Hydranet is just slightly lighter at 4.7 vs 4.9 ounces, and has a slightly softer "hand."

An additional option on the T2 and U2 Sport 2 is to select a woven material - such as Hydra-Net 200 (extra cost), 205 MT (no extra cost, except on Sport 2) for use on the top surface leading edge panel. The advantages of using a woven material here include the superior durability of woven cloth, and the fact that the glider's performance is less likely to suffer significant degradation if flown in the rain. A sail made with a leading edge using woven material will last about twice as long as one made with a "Mylar®" leading edge. In the rain, water droplets tend to bead up on the slick surface of a laminated cloth - polyester film leading edge, which disrupts the smooth airflow and leads to an increased stall speed. This effect varies from glider model to glider model, but in the worst cases it can cause the stall speed to increase above 30 mph, making landing in light winds difficult and even dangerous. A disadvantage of the woven material leading edge is that it will more easily become stained by dirt, and is more difficult to clean.

On the T2 and U2 and Sport 2 you can upgrade the leading edge panel (#1) to UVM10T fabric for an additional charge.

On theT2 only, you can also upgrade the midchord and trailing edge panels (#3 and #4) to Mylar® fabric for an additional charge. (with PX10T it is referred to as the "Mylar®" sail upgrade, with UVM10T it is referred to as the UVM10T complete sail upgrade). This is the typical sail configuration for competition pilots. Mylar® upgrade sails will feature PX10T in the leading and trailing edge (#1 and #4 panel) and PX05T in the midchord. The UVM10T complete sail upgrade features UVM10T in panels #1, #3, and #4. The flight qualities and durability of the woven materials are generally superior to those of the laminates, so if you are not competing we recommend that you stay with the standard woven materials in this application.

See Also: Sailcloth Options Article by Steven Pearson

NOTE: Some sailcloth images shown with dark backgrounds to show fiber details.

Last Modified: 30 October, 2008