UPDATE #6 - January 9, 1998

PART 1: Talk to NASA Engineers!
PART 2: Three Weeks to Go!
PART 3: Why Rotorcraft are Useful
PART 4: Subscribing & Unsubscribing: How to do it

TALK TO NASA ENGINEERS!

One of the ways that Aerospace Team Online project is
interactive is that it gives classrooms and interested
individuals the opportunity to talk to NASA experts
through Web chats. Luckily Aerospace Team members are
happy to take a hour out of their busy schedules to be available
to chat with children. We hope your students will join us.

For more information visit:
http://quest.arc.nasa.gov/aero/chats/index.html#chatting

Another opportunity to interact with Aerospace Team
members is through email Q & A. Imagine the fun for your
class to check the email and find a reply from a NASA
expert.

For more information visit:
http://quest.arc.nasa.gov/aero/question/ask.html

Three Weeks to Go
by Fanny Zuniga

December 29, 1997

Preparations for my Supersonic Transport Wind Tunnel
Test are alive and well. You'd think things might slow
down a bit with the holidays coming. No way!

We just found out that our internal balance doesn't
work the way we thought it did! The internal balance
fits inside the model and is held in place by struts that
mount to the wind tunnel floor. This balance, in turn,
holds on to the model and measures all of the forces
acting on it, like Lift and Drag. By the way, these
forces, like Lift and Drag, are what I will sometimes
call "loads." This is a brand new balance that was built
to handle the high loads this model will generate in our
tunnel. It turns out that the electrical signals coming
out of the balance are arranged differently than we thought,
so we have to redo the wiring that takes the signals to the
computer where they are recorded.

We also have to change the way the computer software
interprets those signals once they arrive at the computer.
Late-breaking changes like this always add a lot of excitement
and stress to test preparations. We have electronics and
software experts on our team that are going to work over
parts of the holiday to fix this problem. We had planned
to move our model and new balance next week into a
special preparation area where we have plans to check
out the health of the balance. Hopefully, our team will
have the balance ready so we can stay on schedule!

Late-breaking changes like this always add a lot of excitement
and stress to test preparations. We have electronics and
software experts on our team that are going to work over
parts of the holiday to fix this problem. We had planned
to move our model and new balance next week into a
special preparation area where we have plans to check
out the health of the balance. Hopefully, our team will
have the balance ready so we can stay on schedule!

That's not all! In my weekly telephone conferences
with Boeing, Lockheed, and Langley Research Center,
we all decided to add some stuff to this test.
On a test like this, we usually want to get a picture
of the airflow on the model. We do this with a number of
methods which I'll introduce to you later. But this week
we decided to add another method, called oil flow pictures,
to this test, which means we added some more runs to our
run schedule. Oil flow is where we put drops of colorful
oil on the wing, run the tunnel, and then take a picture of
where all the drops flowed to. We get really neat
pictures which show us how the air goes around the model.
But then we have to stop the tunnel and clean off the
model before we can get the next picture. This is slow
work and really has a big impact on the run schedule.

On another front, some members of the team wanted
to add more instruments to our model. We already
measure pressures and aerodynamic loads, but they
wanted to add a device which actually measures the
wing tip. We would have to add special devices to
the model, run wires to get the signal from them
to the computer, and modify our software to interpret
the signals. We decided ... No! Sometimes we have to
decide we cannot accommodate something new this
late in the game.

We also found out we were missing some accelerometers.
These go in the model and measure the movement of the
model since it shakes around a bit in the tunnel
when the wind is turned on. It seems everyone thought
everyone else was going to provide these. So now we are
scrambling to find some and install them in the model.

>From the above stories, you can get the idea that
preparing for a test like this takes a lot of
communication, debate, and decision making. When a
miscommunication happens (and they always do) the
test team has to really work hard to make things work,
like with the balance. The goal is to have good
communications, and that's why we have so many meetings
to talk about how things are going. Sometimes this is
the hard part of testing, and sometimes the
fun part!

[Editor's Note: Larry Young is an aerospace engineer at NASA Ames Research Center. He specializes in rotorcraft aeromechanics research. Aeromechanics research is the study of the aerodynamics, dynamics, and mechanical aspects of helicopters and tiltrotor aircraft.]

WHY ROTORCRAFT ARE USEFUL
by Larry Young

December 12,1997

In terms of dollar value, rotorcraft represents only a
very small fraction of the total overall aerospace
industry. Nonetheless, rotorcraft (helicopters and tiltrotor
aircraft) perform all sorts of useful and important functions
within our society. Many of these functions can only be
performed by rotorcraft. Alternatively, even when other
aircraft or equipment can perform a given job, oftentimes
there are clear advantages for using rotorcraft. The
ability to hover and perform low-speed maneuvers is an
extremely valuable capability. The functions that
rotorcraft can perform can be broken into three general
categories:
military, civilian, and public service.

Rotorcraft are an essential part of U.S. national defense.
Rotorcraft perform anti-armor, special operations,
scout/surveillance, utility/transport, and search
and rescue (SAR) military functions. Rotorcraft are
used by all four U.S. military services -- although
the principal users are the Marines and the Army.
Among the current military rotorcraft used by the
U.S. are the UH-60 Blackhawk (made by Sikorsky Aircraft),
the CH-47 Chinook (made by Boeing Helicopter), the AH-64
Apache (made by McDonnell Douglas Helicopter and now
owned by Boeing ), the OH-58 Kiowa Warrior and the
AH-1 Cobra (made by Bell Helicopter Textron Inc.),
and the V-22 Osprey tiltrotor aircraft (Made by Bell-Boeing).

For civilian purposes, rotorcraft have many applications:
news service information gathering, cinematography,
oil-rig and other remote site utility and transport
support, corporate personnel transport, remote site
logging, tourism/site-seeing, heavy-lift applications for
installation/retrieval of equipment from tall building sites,
and many others.

In the public service sector, helicopters perform
exceptional service. Helicopters in public service roles include:
Coast Guard search and rescue/drug-interdiction, police support,
fire-fighting, emergency medical response, disaster relief.
Many inspiring stories can be told about the use of helicopters
for humanitarian purposes. Every year a "Heroism" award is
awarded to a rotorcraft flight crew/operator that performs
the most exemplary "heroic." This is often reported in industry
publications such as "Rotor & Wing." Every day helicopter flight
crews are out flying somewhere saving lives. Whether it is a
Coast Guard crew pulling stranded seamen out of stormy waters
or National Guardsmen rescuing flood, earthquake, or
hurricane victims, or an emergency medical service
helicopter taking a car crash victim to a distant hospital
-- lives are being saved through the use of rotorcraft.

It is because rotorcraft provide so much value to
the public service and the U.S. national defense that NASA
performs rotorcraft research. Even small incremental
improvements in aircraft performance can sometimes have
a tremendous impact on the overall mission capability.
Also, NASA researchers hope that the next generation of
rotorcraft such as tiltrotor aircraft can find their
way into the public transportation mainstream. One day
tiltrotor aircraft may become an essential part of the
aviation transport network -- just as jet/turbo-fan
and turbo-prop aircraft currently are. NASA technology
will hopefully help make that possible.

For more information readers can contact the American
Helicopter Society, Alexandria, VA.

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