Notes for new hang glider pilots--Before you order a new Wills Wing harness...
June 12, 2006 edition
Steve Seibel
steve at aeroexperiments.org
www.aeroexperiments.org
Before you order a new Wills Wing harness, I suggest you
consider specifying a “DHV-length” main harness strap rather than the longer
Wills Wing-length main harness strap.
Wills Wing hang gliders have larger control frames than many
other hang gliders, so a harness with a long main strap allows the carabiner
to be relatively close to the glider’s keel, so that the hang loop running
between the keel and the carabiner can be relatively short. The Wills Wing standard for the distance
from the hook-in point to the base bar is 55 inches, and in this article, by
“Wills Wing-length main harness strap”, we mean a main harness strap
that is sized to give 1 to 2 inches of clearance above the control bar in this situation,
as described on the Wills Wing website.
The DHV standard for the distance from the hook-in point to the base bar
is roughly 48 inches, and in this article, by “DHV-length main harness
strap”, we mean a main harness strap that is sized to give 1 to 2 inches of
clearance above the control bar in this situation. Clearly, the DHV standard is configured around either a smaller
control frame, or a longer hang strap, than the Wills Wing standard, and in actual
practice, most gliders from other manufacturers have smaller control frames
than Wills Wing gliders do. So far, so
good. The problem comes when a pilot
wants to use his Wills Wing harness with a non-Wills Wing glider. It’s been my experience that when a harness
with a Wills Wing-length main strap is combined with a
non-Wills Wing glider, in order to give the pilot adequate clearance above the
control bar, the caribiner has to be only two or three inches below the keel of
the glider. It’s not easy to find a
hang loop this short! I’ve had this
problem when flying gliders with a hang point on the keel (e.g. Pacific Airwave
9m Pulse, Aeros Discus 14) and when flying gliders with a kingpost hang point
(e.g. Laminar MastR 12, Airborne Blade 132).
This issue was particularly aggravating when I visited the Quest Air and
Wallaby Ranch tow parks in Florida—I had the opportunity to fly many different
gliders, but it took hours of scrounging to find hang straps short enough to
allow my harness to work with them. The
gliders with kingpost hang points usually posed the greatest challenge, because
they required a more specialized style of hang strap.
If you do own a harness with a Wills Wing-length
main harness strap and you plan on going to a place where you’ll have the opportunity
to fly many different gliders, it would be an excellent idea to plan ahead and
bring some extra-short hang straps along, including ones suitable for kingpost
hang points. Or borrow a harness with a
DHV-length main harness strap for the duration of your trip.
With flex-wing gliders, this issue may be of more concern to
small pilots than to large pilots. Most
of the flex-wing gliders listed above are relatively small, and the
larger-sized versions of the same gliders come with slightly larger control
frames. With the slightly larger
control frames, it would be slightly easier to make a Wills Wing-length main
harness strap work.
Making exotic twists or double-loops or triple-loops in hang
straps to shorten them can be dangerous.
Shortly before I entered the sport, the leading instructor in my area
was killed due to a mistake in hooking in to a complex hang strap arrangement
of this kind. The caribiner appeared
upon cursory inspection to be hooked into the hang strap, and the hang strap
held the caribiner in place for a few seconds due to friction, but
topologically speaking, the caribiner was completely unconnected to the hang
strap, and after the multiple loops pulled through the caribiner, the pilot
fell.
When a friend recently offered to let me fly his ATOS
rigid-wing hang glider, I found it completely impossible to use my own harness
with its Wills Wing-length main strap. Rigid-wing gliders are typically made with quite small control
frames—with their effective aerodynamic (spoileron or aileron) roll controls
and slender wing chords, the extra roll and pitch control authority that comes
from a low-hanging pilot simply isn’t needed—and my Wills Wing harness simply
wouldn’t fit. Fortunately, my friend
and I were similar in size, so I ended up borrowing his High Energy harness
along with his Atos. Later I flew
another Atos with another friend’s older Wills Wing harness. (Note that while Wills Wing’s website states
that they have standardized the distance from hook-in point to base tube at 55
inches since 1973, it is in fact the case that many older Wills Wing harnesses
are configured with main harness straps that are significantly shorter than
this standard would suggest.)
In summary, I think it may not be a good idea to order a new
harness with the current standard Wills Wing-length main hang strap, especially
if you are a smaller person who will be flying smaller gliders. It’s always easier to fit a longer hang
strap to a hang glider than it is to fit a very short hang strap to hang
glider, and with rigid-wing hang gliders there may not be enough room to fit a Wills Wing-length harness strap even with the caribiner right up against
the keel of the glider.
There’s only
one large caveat to all of this advice: if you are buying a harness like the
Wills Wing Z5, with several different suspension lines that run up to the
caribiner instead of a single main harness strap attached to a long, solid backplate, decreasing the length of these
suspension lines means that they will end up meeting the harness at a more acute angle
(i.e. they will be less vertical), which can decrease comfort. For example, the Wills Wing website states
“We’re happy to accept a harness order for a Wills Wing made harness that
specifies DHV length main supports.
However, you need to be aware that shortening the harness suspension
length makes the angle of the front to rear suspension lines more acute,
putting increased pressure on the shoulders, and measurably compromising the
comfort of the harness. This is not a
factor on a harness with a solid backplate, but on a “soft” harness such as a
Z5, the shorter mains reduce harness comfort to a significant degree.” Elsewhere on the Wills Wing website, one
reads “We strongly recommend that you size your [Z-5] harness mains to fit a
standard Wills Wing hang loop. Shorter
main lengths are available on request, but they increase back compression and
discomfort.” So... what to make of all
this? My Wills Wing Z-5 harness is
extremely comfortable and I would hate to do anything that would compromise
this. However, shorter-than-average
people who are ordering smaller-sized harnesses should keep in mind that their
front-to-rear suspension lines will naturally be slightly less acute than those
of longer harnesses. I think that these
people in particular should strongly consider ordering a harness with a
DHV-length main strap, even if they are currently flying a Wills Wing
glider. As for myself, I’m waiting for
the chance to fly in a Z5 harness with a DHV-length hang strap for a good
6-hour flight, to see if I find the comfort level is any less than the
excellent comfort that I experience with my own Z5 harness with the Wills Wing-length hang strap. If not,
I’ll eventually have my own harness modified to the DHV standard, because I
value the chance to fly gliders other than my own--an Airborne Blade 132
specially fitted with an extremely short hang strap.
While we’re discussing harnesses, I’ll give a few more
pieces of advice. First, in my opinion
a front-mounted chute greatly increases safety, and during a blown launch, I
was once saved from a heavy blow to the chest from a large rock by the
chest-mounted chute of my Wills Wing Z5 harness. Second, before ordering a new harness, find a way to try one on
of the same make and size, with all your flying clothes and with all your
glider bags. My impression is that many
people tend to end up with a harness that fits great when the pilot is wearing
street clothes and has no bags in the back, but is a bit tight when the pilot
is suited up for high-altitude or cold-weather flying and has all his glider
bags packed into the harness. I nearly always fly with
all my glider bags and several jackets, and I prefer not to have to re-arrange the velcro near my harness zipper to expand the harness to get a good fit in this situation, even if
this means that my harness is a bit loose on the rare occasions when I am
flying without my gliders bags and with minimal warm clothing. If you live somewhere warm, rarely climb to
high altitudes, and make a lot of local aerotow flights (or top-landing
flights) without your glider bags, this advice won’t apply to you.
Some of these issues are addressed on the Wills Wing web
site at the following links:
“How to get the right hang height” (including a section
entitled “Ordering a Wills Wing harness with DHV length mains”)
“Z5 Hang Gliding Harness—Sizing and Ordering Information”
