On Friday, September 29th, my friend Angela and I visited this
country's largest and oldest hang glider manufacturer: Wills Wing. If you are a
participant in any type of hang gliding, you have heard of this company. It is
the pre-eminent "force" of hang gliding in the USA.
Most of the information in this write-up is elementary, and it may be boring to
the veterans who regularly read this site, but a novice like me found the
process intriguing. I just ordered my first glider (a Falcon 3 - 170), and
visiting the site where it is being assembled was not only exciting, but also
reassuring.
The design of a modern glider seems extremely complex to me. Details such as
tube flex and wall thickness, reinforcement of sleeves and cable tensions, etc. really leave me confused. My goal was not to understand these details but,
rather, to get an overall "feel" of how these contraptions that often hold me
more than a mile in the sky are manufactured.
Wills Wing is located very close to Anaheim CA, in a relatively small (16,000 sq ft.) modern warehouse.
In spite of being an "industry leader", Wills Wing still border on being a
"cottage" facility. The company is small and personal, and run by a close knit
group of four people who have been involved in hang gliding for almost four
decades and have run Wills Wing for three quarters of that time. They are Steve
Pearson (designer), Rob Kells (marketing), Mike Meier (tech writer manager) and
Linda Meier (office manager). The total full time employee count is sixteen full
time employees. We were shown around by Linda.
Several things impressed me as soon as we entered the Wills Wing sales -
manufacturing headquarters:
1. Throughout, the facility was very clean and very organized. Being an ex- real
estate developer, I have toured hundreds of large and small sized manufacturing
facilities and, except for clean room electronic component assembly, I have
never seen a "cleaner" workspace. This is particularly impressive considering
that Wills Wing not only cuts and assembles sails and frames (relatively 'clean'
activities), but also fabricates metal parts for its gliders. The "fabrication
area" is set of in a separate room - but, even that area was very, very clean.
2. All of the workers seemed to be very much "focused," that is they were
consciously adjusting their activities to not just perform a duty by "rote". This gave me the impression that they really took pride in their activities and
cared about the quality of whatever task they did.
3. Hang gliding is their primary focus - nothing else. In their office, meeting
rooms, and general manufacturing area the only decorations on walls or
tables/desks were pictures and/or diagrams of hang gliding. It is true that
Wills Wing has a paragliding business but, apparently, they are merely
functioning as "distributors" in this area.
Linda explained the general manufacturing process.
Wills Wing has adapted a computerized etching machine from the yachting industry
to "sketch" patterns for different sails and other components on specially
manufactured "fabrics."
This sketching table is very long and at the end of it
there is a computer monitor which allows the operator to enter a pre-programmed
design pattern. The outlined pattern is sketched on the fabric using a
computerized "arm," similar to the Hewlett Packard plotters that were used to
draw graphs in the early computer age.
The machine shown above is a computer-driven combination XY plotter and cutter. It plots the sail panel outlines and registration marks from stored digital
patterns , and then cuts out the sail panels with a moving knife. It operates on
a air vacuum table 48 feet long and 4.5 feet wide, and is accurate and
repeatable to within a few thousandths of an inch. The lateral tables are used
for assembling and registering the pre-cut panels as preparation for the sewing
operations.
Afterwards the outlined fabric is taken
to a cutting table. There it is cut and stitched using industrial sewing
machines and sometimes by hand.
The selection of "fabrics", and the way the sail creates the airfoil is
critical. Each glider has its own fabric (more on that later). Interestingly,
Linda mentioned that if there are discrepancies in a "test flight" it almost
always is caused by a fabric "cut" or fitting error. No matter how exact all
these machines and mortals can be, sometimes the way a "wing" fabric drapes the
gliders metal skeleton, or how the battens may curve it, may not rise to Wills Wing critical expectations. A minute change in sail caused by a batten or
"deformation" in a leading edge renders unacceptable flight characteristics. Obviously, the cutting and assembly of the "wing" fabric is extremely critical
as this is where the proverbial "rubber meets the road"!
The skeleton airframe of each Wills Wing glider is comprised of anodized
aluminum tubes. These "tubes", like all of the integral parts of the glider, are
"aircraft grade" and are stacked in various areas of the facility. They are
linked in triangular designs for strength and, where desired, flexibility.
Most of these aluminum tubes come from Switzerland and France, as Wills Wing has
found that those countries produce the highest grade metrological products for
the glider frames. This must cost Wills Wing more money than a domestic source
and is one more reason why I think that Wills Wing really cares about the
"quality" of what they are producing.
The airframe of the gliders are hand assembled. The fittings to attach the parts
of the airframe are all aircraft quality and kept in a room with labeled
yellow bins.
Each completed airframe is segregated by model. It was interesting to see organized
bundles of folded glider spines labeled with codes like "S2" and "T2" and the
like, as they all were awaiting sail attachment.
Wills Wing recently acquired a Hass Vertical Machining Center (http://www.willswing.com/news.asp?newsSeek=246) that cuts slugs of aluminum and other
metals into specific components for their glider assembly. Previous to this
acquisition they were dependent on outside suppliers to perform the metrological
manufacturing necessary for specific hang gliding components. The machine was
busy cutting ingots of aluminum into fittings when we were there. The scrap
shavings are swept up and placed into a barrel for re-selling. (Shows me these
guys are concerned with keeping financially competitive.) This fabrication area
also houses machinery used got angling and fitting what looked like specialized
speed bars.
Cables and battens are made in a separate area. The cables are hand assembled
and the battens are hand curved over wooden "forms" by an individual who has
worked at Wills Wing for several years. I asked Linda why Wills Wing is the only
hang gliding manufacturer who has the white battens on the left wing rather than
the right and she answered that it's just the way it's always been done and
jokingly replied "we are the right ones, everyone else is doing it wrong."
A related but perhaps more serious discussion followed regarding the Wills Wing
harness hang straps, which some pilots have complained are too long for other
types of gliders. She said that they wanted to be "loyal" to their customers,
and all their straps are designed for Wills Wing gliders. (Of course, you can
"order" a Wills Wing harness with a shorter strap.)
You have to give credit to Wills Wing in that they are the only manufacturer I
am aware of that produces a full-line of gliders, from the training "Condor" to
the custom "U-2". As such, her justification does hold water. Hypothetically,
you could move from one Wills Wing glider to another throughout your entire
flying career without ever having to change or adjust your harness!
The sail is than affixed to the spine of the glider and, after making sure that
all cables, uprights and control bars are attached, the "testing" begins.
Wills Wing actually carts each glider to a "testing" hill using a trailer. The
trailer was close to being attached to the Wills Wing "HGMA Certification Truck"
while we toured the factory. The Certification Truck is a GMC pickup that has a
custom built glider holding type apparatus affixed to it's bed. New glider
designs are attached to this apparatus for load testing. The truck speeds
forwards, and then as the glider is positioned at different angles and the truck
attains different speeds various stress and other airworthiness measurements is
computed.
This human flight testing process occurs for each and every glider before they
leave the factory. Obviously, this is partially done because Wills Wing wants to
indemnify itself from lawsuits for defective products. However, I believe that
they are also truly concerned with "tuning" their end products so when we take
delivery we are assured of a glider that flies "right". If you order a glider
from Wills Wing, your delivery date will probably be influenced by local weather
conditions - as some days they simply may not be able to successfully test fly
your wing.
At the end of the tour, we met Steve Pearson, who was taking measurements of a
new UV resistant sail material they have begun optioning on their T2s.
Despite the fact that we interrupted his "genius", Steve was very
hospitable. He methodically embarked on explaining details regarding performance
enhancements that the shiny fabric may be able to deliver (http://www.willswing.com/news.asp?newsSeek=279)
I really didn't understand much of the technical stuff he said regarding levels
of Mylar backing and UV degradation, but I'm pretty certain that Homeland
Security may have to approve of it's shiny radar reflecting exterior.
We ended the tour by purchasing a cool red helmet and discussing "the future of
Hang Gliding and Paragliding" with Linda.
Yes, I must admit it was all fun. But best of all, the visit gave me increased
confidence that is often needed when we are suspended from these devices a mile
or so in the air. In the case of Wills Wing, they are carefully assembled with
top-line materials and repeatedly tested.
Also, what GAP parameter values would you like to see in Big Spring? I assume
30% arrival at goal, 5 km minimum distance (btw, we will use kilometers at the
meet). What about nominal distance? 100 km?, Nominal time? Two hours?
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