| The first solar plane we
developed at AeroVironment was named the Gossamer Penguin.
The word "gossamer" was an apt description of the appearance
of this strange-looking aircraft that had a structural
weight of only 54 pounds, with a wing span of 71 feet.
Much was sacrificed to save weight and maximize span,
and this presented serious problems when handling the
aircraft on the ground. The Penguin was barely strong
enough to stay together in the light winds and low turbulence
of the early morning. Moving the Penguin back to the
hangar at the end of a morning flight was much like
walking a 71-foot span kite home from the park.
To move the aircraft about on the ground, as well
as to stabilize it during take off and landing, we needed
to come up with a lightweight solution. An obvious one
would be to assign "wing walkers" to mind each wing
tip. A walker would simply pull down on the wing that
was being lifted up by the gusts. The tips of the Penguin,
however, were over eight feet above the ground. If the
aircraft was allowed to tip far enough to one side for
ground crew to hold it, then it would have already raised
the other tip high into the wind. At that point, the
aircraft was likely to flip over.
To solve that problem, we used a string of Kevlar®
tied to each tip. It was extremely light and thin, so
the performance penalty of carrying the string along
in flight was negligible. Unfortunately, this elegantly
simple solution had one minor flaw, which, like all
such flaws, was discovered the hard way.
When the winds were calm the string worked very well,
and kept the wings level and away from the ground. But
when a strong wind caught us walking the Penguin home,
it required some tension on both strings simultaneously
to keep it balanced on the dolly set under the main
wheel. Accordingly, the walker would get used to holding
the string at a certain height and a certain tension,
and when a gust began to lift his wing up, he would
feel the increasing tension in the string, and naturally
react by pulling down harder on the string.
Sometimes one wing walker would pull down inadvertently,
which pulled the opposite wing up slightly. Feeling
this tug, the other walker would assume a gust was hitting
his wing, and would begin to pull down harder on his
wing to prevent the wing from lifting more, and getting
even more lift as the wing rose higher against a side
gust. The first walker would now feel a strong pull
on his wing and would resist even harder. Since the
wings weren't designed to take large point loads near
the tips, a disaster seemed imminent.
The fix didn't require a high-tech solution. After
discussing the problem, the flight team realized that
by simply having each wing walker alternatively call
out an estimate of how hard they were pulling on their
string, they wouldn't fight one another. When the flight
team tested the system, they discovered that it didn't
even matter if the walkers' estimates were accurate;
they just needed a rough idea of the balance of their
In practice, as a pair of walkers got used to working
together, they rapidly developed a sixth sense that made
their estimates surprisingly close. But this job could
quickly get boring, which meant we often changed walkers
during a test day. Fortunately, we found that any new
team of walkers would quickly calibrate each other after
only a short orientation. The result: no broken wings.
over and over that the most common solution to problems
in any group of people that must work together has
been better communication.
The Gossamer Penguin solar-powered aircraft was my
first project management experience. Since that time,
I've found over and over that the most common solution
to problems in any group of people that must work together
has been better communication. Sometimes it's a system
or process, sometimes it's an attitude adjustment, but
improved communication almost invariably helps a team
be more productive and effective. Just as importantly,
it generally makes the work a lot more fun.
Search by lesson to find more on:
Morgan is head of Morgan Aircraft & Consulting
and a senior technical advisor to NASA. Morgan oversaw
the development of over 35 Unmanned Aerial Vehicles
(UAVs), including NASA's Helios and Pathfinder aircraft,
during his tenure at AeroVironment, Inc. His first
ASK feature, "Coming
of Age," appeared in Issue 16.