T. Miralles is a senior program manager at AeroVironment,
Inc. where he is responsible for new business and concept
In 1981, he completed his BS in Aeronautical Engineering
at California Polytechnic University at San Luis Obispo.
With his twenty years of experience in aerospace, Miralles
is currently working on the aerodynamic and conceptual
development of unmanned air vehicles (UAV) and related
technologies for terrestrial and planetary applications.
He also developed and managed the "Vector" vertical
take-off and landing UAV design and flight demonstration,
which included the first known successful transition
from hover to forward flight and back to hover for a
vehicle of its class. Miralles was also involved in
several other innovative ground and air vehicle concepts
and technologies, including a Mars Airplane design,
and was a major contributor to several NASA mission
also teaches a summer-term course in Automotive Aerodynamics
for the school of Industrial Design at the Art Center
College of Design, Pasadena, CA. A licensed private
pilot, Miralles took First Place in the 2000 Region
12 Sports Class glider competition.
links to this scientist's home page and other related infomation
please see our resources
Luis Esparza asked:
is it that insects seem to fly much more efficiently
than the machines scientists have been able to build?
Insects can fly really fast (too fast to run away from
when they chase you), really far like bees looking for
honey, and can hover and stop almost at will. Is it
possible for us duplicate this level of performance
now or in the near future?
Good observations. It will be quite some time before
we can emulate the flight of insects, but I think we
will eventually get there. Insects first started flying
about 300 million years ago. Man has only been flying
on the wing for the last 100 years. With larger flying
machines, man has been able to fly to far greater heights,
carry more weight and fly faster than nature has ever
been capable of -- but that was the easy part. We're
small scales, the size of small birds and insects, man
made flying machines have not even come close to achieving
the performance and agility of nature's flying creatures.
Serious research into the kinematics of flapping flight
has only been accomplished in the last six years or
so. We are currently limited by our technology.
important limitation is the power and energy density
of batteries, which fall far short of what's required
to mimic insect flight. For instance, a dragonfly requires
about 0.02 Watts for level flight. To fly for just 10
minutes the battery alone would weight about 1 gram.
A complete dragonfly typically weighs only 1 gram, and
that includes a flight control system, collision avoidance
system, an energy replenishment system, a reproduction
system, and more!
problem facing scientists and engineers is the complexity
of flapping flight. Although we now have a good understanding
of the kinematics involved, the materials, sensors,
mechanisms and actuators required to replicate flapping
flight on a small scale do not yet exist.
more technical information on flapping flight:
The Biokinetics of Flying and Swimming, A. Azuma, 1992
Frank Yeske asked:
do you think that these "eyes in the sky" model planes
will be available to the public in the future? I have
always been interested in combining photography and
flying. I'll be looking for your BLACK WIDOW in the
stores. I'm a 48-year-old steel worker with the heart
of a 10-year-old. Thanks for listening.
Perry Thornton asked:
two girls were watching Scientific American Frontiers
last night and they got very excited about the Black
Widow and the other plane with a video camera. If we
wanted to build a plane like this, how would we get
Igor Pimenov asked:
my name is Igor Pimenov and I'm 14-years-old. I have
been in the R/C Planes hobby for over 3 years. I have
a huge interest in small aircraft that have a wingspan
of 20 inches or less. I'm very interested in your Black
Widow. Could you tell me more about the type of servos
and batteries you used? Could you tell about the type
of camera you used and where you got it?
Perry and Igor,
It is very unlikely that an airplane like the Black
Widow will be in stores any time soon. The six-inch
span constraint forced us to develop highly specialized
electronics and sensors to achieve the desired performance.
The commercially available parts were just too heavy
and inefficient. Even the servos are highly specialized
and cost $2000 each.
good news is that there is a growing movement in the
model aircraft community that is developing very low
cost, easy to fly, light weight and small electric airplanes
-- and you can buy them today. You can even buy a camera
and downlink transmitter for the video. These models
are typically much larger and don't perform as well
as the Black Widow, but they are much more practical
for recreation and great for both kids and adults captivated
by the idea of flight.
are a few web links for more information:
Hector Sburlati asked:
I have designed and built a small scale of an airplane.
The model is a delta design with 2 turbo-props pushers
mounted on top at the rear of the plane. I would like
to make a flying model but I need to know the c.g. before
I can start building. Is there a formula that I can
use to figure it out? I'll appreciate it.
are some general rules-of-thumb which can help approximate
the center-of-gravity (c.g.) location for a flying wing.
But you have to be careful, especially with airfoil
selection, twist distribution and thrust line placement.
These factors can greatly effect the c.g. location and
flying qualities of a flying wing. Without more knowledge
of your design, I can only recommend some reading that
should be helpful to you. Tailles Aircraft in Theory
and Practice, by Karl Nickel and Michael Wohlfarht,
AIAA Educational Series, is a great place to start.
Also, look for reference material on the Northrop and
Horten flying wings at your local library.
can also take a "cut-and-try" approach to estimating
c.g. position by building very simple and low cost glider
models to experiment with c.g. position and trim. Start
with a simple thin-sheet balsa wood or egg-crate-foam
sheet model with a 12 to 16 inch span, and don't worry
about the airfoil shape for now, just make it a flat
plate. Using clay or pennies taped to the nose, balance
it at a point just forward of the mid-point between
the nose and trailing edge. This works as a good starting
point for a simple low aspect ratio delta wing planform
but not a higher aspect ratio wing. Then trim the glider
by bending the trailing edge up small amounts until
it flies properly. And don't forget to put a vertical
tail on the rear. You will have to make adjustments
to the c.g. and trim depending on the specifics of your
should get you close enough to work on your larger flying
model and give you some practical understanding of the
longitudinal stability of your design. But be prepared
for big changes depending on your choice of airfoil,
body shaping, thrust lines and other details of your
was very interesting watching the Pointer launched by
one man, and then, kind of float/glide down to earth,
after you had cut the engine, for a (usually), soft
landing. But, even though you have cleverly designed
easily damaged parts as replaceable, why risk a hard
landing at all? It seemed that once you cut the engine,
it was pretty easy to determine where the plane would
come down. Why not get two people to stretch out a net,
and catch it in between them? No hard crashes; no replaced
parts. The plane can't be that heavy if an ordinary
joe can throw it into the air. Maybe a soft net, held
horizontal, 20' wide, or a circular net on a soft flexible
tubing, something like camping tent flexible, joined
poles, maybe 15'-20' in diameter.
Clearly you have made some good observations and pondered
the problem we have wrestled with for some time. As
it turns out, we've explored the possibility of landing
our unmanned aircraft a number of ways, including the
use of nets.
Pointer weighs about 9 pounds and has a 9-foot wing
span. Using the deep stall auto-land, an expert pilot
can usually land it within 20 feet of a pre-selected
point in daylight. A foot soldier with minimal training
(about one day) is usually lucky to get it within 100
feet, and with some practice can usually land within
50 feet. Moreover, it is usually flown at night making
it hard to do precision landings. It would have to be
a very large net. The Pointer is actually designed so
that some of the parts come off in a landing and can
be snapped back together in a few seconds. Usually,
none of the parts actually break.
because Pointer is designed to be quickly and covertly
launched and retrieved by troops, we had to keep the
number of parts and steps in the process to a minimum.
Having to carry the parts for a net means leaving something
else behind or having to carry more weight. Having to
set-up and take-down a large net means being exposed
longer and limits the users' mobility.
Robyn Allen asked:
am a high school student in central California who is
very interested in going to Mars someday. I watched
the Scientific American Frontiers show in which you
spoke about your invention (the folding plane) and I
am wondering if you can give us information about how
you got involved with the space program. I am really
interested in what types of classes you took at school
and essentially what your stepping stones were to get
to where you are now. Also, I would love any information
about exactly what your title is and what kind of people
work in your department. Thank you very much. P.S. I
fly gliders too!
It's good to hear from young people that wish to someday
realize the dream of traveling to another planet. I
truly hope you succeed and that I will see you walking
on Mars via my television (or whatever it is we're watching
If you have a desire to learn more about the space programs
and particularly what is going on for Mars Exploration,
see the web sites:
of my involvement in the space program is through the
Mars Airplane activity. How I became involved is far
too long a story to tell in full here. But I'll try
to answer some of your questions.
am an aeronautical engineer by training, with a degree
from California Polytechnic University in San Luis Obispo,
1981 (before you were born!). My course work included
studies in aerodynamics, propulsion, structures, physics,
calculus and many other subjects. Most of the classes
were required, and I took some post graduate technical
classes for electives.
as important as the academic studies was my passion
for anything that flies, beginning when I was very young
making model airplanes and continuing through hang gliders
and sailplanes during high school, university and beyond.
I still fly as often as I can. Often, I would look for
any opportunity to help on projects like a human powered
aircraft, or take a summer job at an airport, even offer
to wash an airplane in hopes of getting a ride. The
value of learning through practical experience motivated
by passion for a subject cannot be underestimated.
career started while in school designing, testing and
marketing hang gliders for two manufacturers in California.
After graduation, I worked for several years at Northrop
on the B-2 and a number of other exciting projects.
Then, after a couple of years at North American Aircraft,
I was offered a job at AeroVironment (AV) where I am
now a Senior Program Manager and do a lot of new business
development. I've been at AV for over 11 years. I still
get to do a lot of fun technical work.
first became involved in space technology through a
relationship with the Jet Propulsion Lab (JPL) and involvement
in the early Mars Airplane concept studies of the late
1970's. Later on, AV consulted for the energy storage
and propulsion systems on the Pathfinder Sojourner rover.
In the last few years, I had been working on projects
involving small, unmanned aircraft that folded into
containers and could be deployed from other aircraft
or launched out of tubes. I was also working on the
problem of flight at 100,000 feet here on earth (an
environment similar to the Mars atmosphere). When JPL
needed a consultant to develop a small airplane that
could be folded into an entry probe for Mars, we seemed
to be a logical choice.
am very fortunate to be working with a lot of talented
and dedicated individuals. Most (about 80%) of our division
is comprised of degreed engineers. We also have several
extremely talented craftsmen that turn concept designs
into reality. What AV has been able to accomplish would
not have been possible without the contributions of
everyone working on each of those projects. Although
education is important when we look to hire someone,
great value is placed on personal experience, demonstrated
accomplishments, desire to learn and ability to be a
contributing team member. Most schools unfortunately
do not offer many opportunities, either in class or
in extracurricular activities, to gain experience working
with other individuals as a team toward a common goal.
It is a valuable experience. Seize it when the opportunity
William Hughes asked:
saw the Sky powered glider with Alan Alda on PBS. Is
it possible to get one of these to do research on population
counts of Sea lions and birds here on the Oregon Coast?
Thank you, Bill Hughes
Bill Chambers asked:
I am a vegetable farmer interested in sustainable agriculture
and I think that a possible application for your "spy
plane" would be for crop scouting fields for pests,
especially if the camera can be equipped for recording
in the near infrared. Can you tell me how to get more
information on purchasing or renting of one of these
for your help.
Your suggested applications are very insightful. A number
of government projects have or are investigating similar
things using unmanned air vehicles (UAV). This includes
surveying crops to see what portions of coffee orchards
are ready for harvest, detailed mineralogical surveys,
and other applications. Although I have not personally
heard of anyone wanting to use UAVs to conduct aerial
surveys of wildlife, it would not surprise me if someone
has -- it sounds like a good idea. Practical UAVs for
these kinds of applications are on the horizon, but
not yet available to the field researcher, farmer or
entrepreneur wanting to make a business of this. The
problem is primarily the high cost of these systems,
not so much the technology.
The individual markets for non-military applications
are very small and do not, in and of themselves, justify
the kind of investment required to develop the products
and services needed. Most likely, the military will
have to make a large procurement in order for the economies
of scale to reduce the cost of UAV systems to a level
that is acceptable. Then, it will be up to small, specialized
companies to take the production UAV and adapt it for
a specific commercial or science application.
Small and inexpensive video cameras are already available,
however the near infrared cameras and other specialized
payloads needed for many applications are still much
too large and costly. Then we need to develop the computer
codes and displays that make it possible for a farmer
or field researcher to interpret the data and use the
information to take action. These too do not yet exist.
More government investment is still needed.