Inflatable Wing concept tested at Dryden

A deployable, inflatable wing technology demonstrator experiment has
flown at the NASA Dryden Flight Research Center, Edwards, Calif. The
inflatable wing project represents a basic flight research effort by
Dryden personnel.

Recalling Hugh Dryden’s vision for the purpose of flight research,
Jeff Bauer, manager of Dryden’s inflatable aircraft project, noted
“With these tests we have put some reality behind the many imagined
applications for inflatable winged aircraft.”

Three successful flights of the I2000 inflatable wing aircraft
occurred. During the flights, the team air-launched the
radio-controlled (R/C) I2000 from an R/C utility airplane at an
altitude of 800-1000 feet. As the I2000 separated from the carrier
aircraft, its inflatable wings “popped-out,” deploying rapidly from
pressure provided by an onboard nitrogen bottle. The aircraft
remained stable as it transitioned from wingless to winged flight.
The unpowered I2000 glided down to a smooth landing under complete
control.

As a result, flight data now verifies and validates computer models
of inflatable wings for the future. The I2000 was equipped with a
miniature flight data recorder designed by engineer Jim Murray. That
data, in addition to video and the photographic record, provide
valuable insights into the aircraft’s flight dynamics.

“We are particularly interested in the dynamics of the vehicle during
the rapid wing deployment, the transition from wingless flight to
winged flight. We proved that we have a good flying vehicle during
the transition to wings fully deployed,” says project engineer Joe
Pahle.

Flight of the I2000 followed a conservative “build-up” approach
common in developmental testing. The Dryden team began flying the
I2000 with rigid wings having the same physical dimensions as the
inflatable wings. Following successful flights with the conventional
rigid wings, the actual inflatable wings were flown pre-inflated on
the I2000. These risk reduction efforts were all geared to narrowing
the possibility of trouble in launching and flying with the
deployable wings. Tony Frackowiak of Dryden’s model shop built all
the glider models and R/C aircraft used in the project and served as
the I2000 pilot.

“There were no suprises since I was well prepared for the actual wing
deployment flights,” says Frackowiak. “We flew the I2000 build-up
style in the powered mode with the wings pre-inflated. The drop and
wing deployment was so smooth that the rest of the flight and landing
was uneventful,” Frackowiak said.

Each inflatable wing is 2.7 feet-long for a wingspan of just over
five feet, not including the fuselage. In the undeployed stowed
state, the wings fit in a container the size of a small coffee can.

Wing deployment time is typically on the order of a third of a
second, almost faster than the human eye can see. The specially
designed wings utilize compressed nitrogen gas for the
near-instantaneous inflation. A pressure regulator mounted on the
nitrogen pressure vessel keeps the internal pressure of the wings at
a constant 200-250 pounds per square inch (psi), reducing the
possibility of wing-sagging due to low internal pressure or high
external pressure. The nitrogen tank was pressurized to 500 psi in
order to allow excess gas to make up any pressure losses in the wings
due to leakage.

Having completed the I2000 flights, the next goal of the project is
to fly a four-foot long X-24A model with the inflatable wings by the
end of summer in hopes of proving the concept of using deployable
inflatable wings with lifting body vehicle configurations. The X-24A
model effort is a complementary but separate effort in demonstrating
the utility of inflatable wings.

The X-24A shape was chosen because it has a well-established
aerodynamic database. It represents lifting body vehicles in general,
and, in particular, has upper body flaps for additional roll control.
The inflatable wings do not have flight controls, so the body flaps
are critical for flight control. The I2000’s tail surfaces filled the
gap on that standard configuration airplane. The buildup to the
inflatable wing X-24A flights will include flying the model with
rigid wings first, the same procedure used for the I2000. Potential
advantages of utilizing inflatable wings on future lifting body
vehicles include providing greater range, maneuverability, and lower
landing speeds than totally wingless vehicles.

Possible future applications of inflatable wings include earth
science aircraft, any limited-volume aircraft, and planetary research
aircraft. A high altitude, long endurance platform could conceivably
carry multiple small deployable inflatable wing aircraft to release
as “probes” to more closely investigate areas of interest located by
the platform’s sensors.

The deployable inflatable wings were constructed by Vertigo, Inc., as
a subcontractor for a U.S. Navy Phase II Small Business Innovation
Research contract. The contract previously utilized the wings tested
on a gun-launched munition to add glide capability to it.

– NASA –

NOTE TO EDITORS:

Photos are available on the Internet under NASA Dryden Research
Aircraft Photo Archive, Dryden News and Feature Photos, URL:
http://www.dfrc.nasa.gov/gallery/photo

Video footage is available from the Dryden Public Affairs Office to
support this release. For photo prints or video dubs, please call
(661) 276-2662.