Paul MacCready is founder and Chairman of AeroVironment,
Inc., which specializes in innovating efficient, alternatively-fueled
vehicles for land, sea, and air. MacCready received
his B.S. in physics from Yale in 1947, his M.S. in physics
from Caltech in 1948, and his Ph.D. in aeronautics from
Caltech in 1952.
In 1977, his Gossamer Condor won the $95,000 award offered
by British industrialist Henry Kremer for the first
sustained, controlled human-powered flight. The plane
now hangs in the Smithsonian Institution's National
Air and Space Museum in Washington, D.C., beside the
Wright Brothers' 1903 Flyer and Lindbergh's Spirit of
then, MacCready has led teams that have created many
additional pioneering vehicles. Working in conjunction
with General Motors, MacCready and his group developed
the GM-Impact, a battery-powered car with remarkable
performance that became the catalyst for recent developments
in alternatively-fueled vehicles. In 1998, the solar-powered
Pathfinder II, a huge, remotely-piloted descendant of
the Solar Challenger, reached the stratospheric altitude
of 80,200 feet- the highest a propeller plan has ever
member of many professional organizations, MacCready
is president of the International Human Powered Vehicle
Association. He has been awarded numerous honorary degrees
and international honors, including the 1982 Lindbergh
Award for his "significant contributions toward creating
a better balance between technology and the environment."
links to the scientist's homepage and other related information
see our resources page.
Tim W. Jones, Sr asked:
Could a slow flying jet plane approaching from the left
and underneath of a large propeller driven craft and
in close proximity, quickly give full throttle and suck
the supporting compressed air from underneath the larger
plane's left wing through the jet's intake, causing
the larger plane to slide left and down into the jet?
If this could happen, it may have happened and would
explain a Chinese pilot's declaration that our reconnaissance
plane made a sudden maneuver down and left causing the
collision. I am thinking that the front end of an operating
jet engine is similar to a vacuum cleaner. How off base
Thanks in advance for your time.
Tim W. Jones, Sr.
Considering the large size, weight, and therefore lift
of the U.S. reconnaissance plane, an abrupt power change
by a small fighter beneath its wing would probably not
have a significant effect on the big plane╣s motion.
However, the vortex wake that assembles in the vicinity
of the large plane╣s wing tip, and trails backward,
is strong, and has often flipped over small planes that
make the mistake of getting involved in it. Big following
planes can be upset slightly by the vortex wake system,
but are only inconvenienced, not flipped, because their
wings span across the small scale flows and tend to
average out the effects. The time and space persistence
of these trailing wakes are the main reasons for the
large spacing between landing airplanes at airports,
and the resulting traffic delays and low capacity of
planes don't move abruptly. Logic suggests that a "hot
dog" fighter pilot kept zooming close in order to be
annoying or threatening, misjudged a dangerous move,
and caused the collision. The testimony of the other
fighter pilot about the big plane initiating the accident
is likely filtered by the politics of the country he
represented. No pilot of a large plane with many people
on board would initiate a life-threatening maneuver.
Political posturing required those behind the perpetrators
of the collision to an illogical "your face hit my fist"
do not have enough facts about the incident to have
an absolutely definitive conclusion, but feel the charges
are less than 1 out of 1000 that the cause was other
than reckless maneuvering on the part of the fighter
Colin P. Varga asked:
first saw your story back in 1977 regarding the Condor.
It was very impressive. Do you think small passenger
planes could be powered by an electric engine? Would
a fuel cell be a good power source for this type of
vehicle? Will solar panels be powerful enough? Thanks,
Planes carrying people can be battery powered. Our piloted
Solar Challenger flew by battery power in 1980 during
its development program. In 1981 it carried its pilot
163 miles from Paris to England at 11,000 feet, using
only photovoltaic cells ("flying on sunbeams"). Some
auxiliary powered sailplanes are powered by batteries,
and small 2 to 4 person planes could certainly be made
that could fly 100 miles on present advanced batteries,
and probably 3 times further on the batteries likely
to be available 5-10 years from now. Energy from burning
fuel (reciprocity or rotary engine, or fuel cells) can
provide much more energy per pound than can batteries,
and also have high power for their weight and at relatively
normal aircraft, where economy and long range (and occasional
high power for safe takeoffs) are needed, combustion
of fuel is the logical approach. If you don't want to
use fossil fuels and release CO2, you can make ethanol
from plants and use it to power planes in a total system
that releases no CO2.
can be generated by wind or solar cells or hydroelectric
systems or nuclear plants, and can be used to generate
hydrogen for fuel cells or for combustion in reciprocating
or rotary engines. Onboard storage is the problem.
aircraft is perhaps the highest level use for liquid
fossil fuel. Surface vehicles, without the priority
on low weight, can more easily draw on other options.
Ditto for heating.
fields do you graze in to find your best creativity?
I mean, what authors, artists, musicians, scientist
and other inventors inspire you?
Conferences, books, magazines, newspapers, occasionally
TV, interaction with associates and strangers, all provide
information, insights, and stimuli. It is helpful if
you have a proactive attitude and a feeling of being
empowered. Even if the attitude and feeling are not
justified, they put you in a proactive position of figuring
out how to make things happen, rather than just studying
or observing or ignoring. Most helpful were some mentors
in the early 50s who expected me to do things beyond
my resources or ability. I didn't want to let them down
and so charged ahead and, to my surprise, found I could
do more than I had thought. I find myself drawn to generalists
rather than specialists, because generalists tend to
find connections between fields, or discover a fertile
mulch in the interactions between fields. (Youngsters
are especially good at being generalists, before the
stultifying effect of standardized testing erodes the
enthusiasm to venture.)
doesn't try to be creative. One just tries to solve
challenges. If you can't do it this way, try another
way, and another or reexamine the situation and find
that some other nearby challenge is solvable.
My name is Jack, I am an 11 year-old and I found
your television show extremely interesting. I was wondering
how you get proper funding for all of the materials
you use for your magnificent airplanes?
Another Awestruck fan,
You can focus your personal resources on helping feed
your key interests rather than diluting the resources
for other tasks. If you really want to do something
and communicate it to lots of people, you often find
someone (or some organization) that wants to help. (I
have found that everything that deserves being done
eventually gets support, although it may be many years
before the support materializes.) You can't do much
alone. Asking for help, and ignoring rejection, are
Michael Gibbs asked:
Greetings to another Caltech grad. I also have a degree
in Physics from there. My question is: What is the latest
progress on the attempt to make a human powered helicopter?
I think a scaled down version might be a good candidate
for a vehicle that can hover and carry a small camera.
What do you think?
reality of a human-powered helicopter is that, with
the simple formula for static thrust of a rotor, you
quickly find you need a disk diameter of 150 feet or
so for serious human-powered helicopter flight. It can
be done, but the task is huge, and the dollar prize
not worth the time expenditure. There are many more
exciting, never-been-done-before challenges that can
be accomplished with much less work.
Jack Conway asked:
Was very impressed with your story on "Flying Free"
with Alan Alda. Made me feel like a kid again. Saw the
segment on using insect wings to discover their "heavy
lifting" abilities. What about the Bumble Bee, the one
insect that is too heavy to fly -but does anyway? Just
thought I'd throw in my two cents just in case someone
had overlooked it.
for your time and keep inventing!!
old bumblebee myth is a combination of science and media.
Bumblebees fly. They have some great tricks up their
sleeves that humans didn't understand fully because
the tricks don't help at the scale of planes that carry
humans. As interest in microfliers grows, so does attention
to the varied flight solutions of insects. There is
superb research about insect flight going on at universities,
and some excellent books are available. Humans are getting
close to being able to duplicate the aerodynamics of
the bumblebee, but we are far from being able to provide
the power and energy in such a small package.
Carl B Freeman asked:
many projects they were looking for "extra lift." Have
you considered filling the insides of some craft with
helium to make them lighter? Inflatable craft would
have simplicity and a strength from being "inflated."
Kremer Prize rules precluded the use of buoyancy gas.
Our other planes would benefit very little from it,
or in the end be hurt by the complexity and weight of
sealing. At sea level, the lift of hydrogen in our biggest
(over 200' span) plane might be 60 lbs, and it would
take about 30 lbs of tape and seals to keep the gas,
hydrogen or helium, in the wing, and add lots of complexity
where spars or control lines enter and leave the wing.
At 100,000 feet the lift would be under a pound (at
60,000 feet around 10 lbs), but cost the 30 lbs of extra
weight of sealing. Also, the gas tends to leak through
the plastic rapidly, quickly eroding any possible benefit.
16 years old and a private pilot and was wondering how
does a model airplanes with the flapping wings thrust
forward? Is it because of the air getting pushed around
by the wings? Don't the planes shake themselves to pieces?
a moving canoe, put a paddle in the water with the blade
parallel to the motion. As you move the paddle away
from the boat (twisting a bit if necessary to avoid
stall) it has a big lift force perpendicular to its
direction of motion. Direction of motion in the fluid
is say 30║ out away from the boat heading, so the lift,
being 90║ from the paddle motion through the water,
is 60║ relative to the boats heading which means thrust.
Bring the paddle toward you, and again get the forward
thrust. A bird╣s wing provides thrust the same way (except
flapping up and down rather than sideways) with a bit
of bias angle of attack to provide the average lift
thrust keeps it aloft. The bird╣s body goes up and down
a bit (but the head usually stays rather steady). Propellers
make flight for humans comfortable and efficient. Birds,
and all natural fliers, can't use rotary motion and
so must get by on flapping.
Bill Havrilla asked:
used to be a basic "starter" formula for concocting
your own thin-film covering material for indoor flyers...seems
like I recall it being made with a nitrocellulose base.
Do you happen to know of any such animal or where I
could look for it's "recipe"?
Thanks. ...nice episode
the internet for books on model airplanes, especially
indoor models. Here are some organizations/publications
that are helpful.
AMA and NFFS have good connections to indoor models.
Academy of Model Aeronautics (and its official publication,
Model Aviation, available at newsstands). An AMA membership
gives you automatic liability insurance.
5151 East Memorial Drive
Muncie, IN 47302-9252
AMA sells Detta Dart entry level kits, and videos, books
& Electric Modeler
P.O. Box 4250
W. Richland, WA 99353
Web site: www.semodeler.com
Free Flight Society
3317 Pine Timbers Drive
Johnson City, TN 37604-1404
Web site: freeflight.org
Radio Control Microflight
100 East Ridge
Ridgefield, CT 06877-4606
A book on the subject is "Indoor Flying Models" by Lew
Gitlow, 1993. Lew Gitlow, Box 5311, Salem, OR 97304.
$22 + $3 shipping.
Philip Greenwood asked:
you considered producing a "homebuilt kit plane" like
a solar-electric Gossamer Condor?
Gossamer Condor was a very impractical plane made for
one purpose win the Kremer Prize as quickly and cheaply
as possible. It is large, cumbersome, can't be flown
in wind above 4 or 5 mph, and is ready to break at any
moment. There are more rewarding and safe hobbies to
get into. The Solar Challenger was a successful solar
electric plane, strong enough for turbulence but under-powered.
At great expense its solar cells could only put out
power equivalent to a medium size gasoline model airplane
Robert Sterchak asked:
Last week I came up with an idea involving flying bird
models. Viewing "flying Free", I see nothing quite like
it. I have no resources to investigate patenting or
development. Is it possible to send it to you to evaluate
and see where it goes?
can explore patents free on the Internet through the
U.S. Patent and Trademark Office at www.uspto.gov.
We don't have the time to examine and evaluate new ideas
from outside. In fact we are too busy even to explore
our own new ideas properly. Sorry.
Richard Trask asked:
I would like to try to build a small "flapping flyer"
like the one that you demonstrated on the program. It
was incredible the way it fluttered in a circular flight
path. Is there any way that I could get plans for that
design? I am quite skilled at making things, and would
love to try it.
construction is very difficult and the plans give no
details. Try the Internet for information on ornithopters.
Also contact Industrial Evolution (indev.hypermart.net)
for membership in the Ornithopter Society ($12/year).