Andrew Yee[_1_]
June 13th 08, 02:35 AM
Alan Brown
NASA Dryden Flight Research Center, Edwards, Calif. May 12, 2008
(661) 276-2665
RELEASE : 08-18
NASA at 50: Flight Research Center's LLRVs Led to Apollo Lunar Landers
By Christian Gelzer, Tybrin Corp.
Chief Historian, NASA Dryden Flight Research Center
EDWARDS, Calif. -- President John F. Kennedy's 1961 challenge to put a man
on the moon and return him safely to Earth by decade's end electrified much
of the country, but it floored most NASA engineers.
Not that going into space was a new idea to engineers at NASA, or its
predecessor, the National Advisory Committee for Aeronautics. NACA engineers
had been discussing putting humans into space since the early 1950s. But
contemplating orbital flight is not the same thing as planning for an
excursion to the moon's surface.
Interestingly, two organizations were simultaneously thinking about the same
thing: regardless of what vehicle NASA settled on to get to the moon,
astronauts would need something to simulate, here on Earth, the descent to
and landing on the moon. The two organizations were NASA's Flight Research
Center at Edwards, Calif., and the Bell Aircraft Corp. in Niagara Falls,
N.Y.
Among the challenges was simulating the moon's gravity, which is only a
sixth of Earth's. How, in the early 1960s, are you going to do this with a
wingless aircraft? What method will you use to negate five-sixths of the
Earth's gravitational pull in flight? How will you compensate for the fuel
you burn off while in flight? (Keep in mind the state of computing in 1962,
and especially, of portable computers.)
And how are you going to reproduce the moon's lack of atmosphere right here
on Earth? Flying in a vacuum is quite different from flying in an
atmosphere, more different that you would expect, as the astronauts later
attested. Even small wind gusts will affect a simulation like the one in
question.
What NASA and Bell came up with was the Lunar Landing Research Vehicle, or
LLRV. The LLRV -- quickly dubbed the Flying Bedstead -- was powered by a
General Electric CF-700, the fan-jet version of the J-85 engine, mounted
inside two gimbaled rings. The dual gimbals enabled the engine to provide
true vertical thrust -- perpendicular to the Earth's surface -- while
allowing the rest of the vehicle to rotate freely in pitch and roll.
Eight thrusters were fixed to the frame as lift rockets, capable of
producing 500 pounds of thrust each. These were used for lift when flying a
lunar landing simulation.
For maneuvering, the engineers chose 16 smaller thrusters, four at each
corner of the vehicle. These were fired in pairs, one up and one down at
opposite corners of the vehicle. Half of the 16 thrusters were adjustable on
the ground to vary their output from 18 to 90 pounds thrust so engineers
could experiment to find which setting was best suited for training.
The craft carried two fuels: JP-4 for the jet engine and hydrogen peroxide
for the thrusters. The hydrogen peroxide was a 90 percent pure solution, and
was pressurized with helium to ensure a constant flow to the thrusters.
Bell delivered the first LLRV to the Flight Research Center in the spring of
1964. The second vehicle followed not long after. Ground tests began once
the first vehicle was uncrated and assembled, and in October of that year
Joe Walker, the center's chief pilot, took the LLRV up for its first flight.
The CF-700 engine could produce 4,200 pounds of thrust under ideal
conditions, barely enough for a thrust-to-weight ratio of 1.05 to 1.
Perhaps more remarkable than anything else about it, the LLRV was a
fly-by-wire aircraft -- one of the very first -- controlled by three analog
computers. There was no mechanical backup control system of any kind,
primarily because of weight considerations.
In preparation for the first flight the vehicle was towed to South Base at
Edwards and covered with two tarpaulins. That night it snowed and when the
crew arrived the next day there were eight inches of snow on the vehicle.
The flight tests at the Flight Research Center convinced NASA that the LLRV
was a viable training tool, and the agency contracted with Bell for three
additional vehicles. Built according to modifications made at the Flight
Research Center to the two LLRVs, the three new vehicles were dubbed Lunar
Landing Training Vehicles, or LLTVs.
Although the Apollo astronauts used other Lunar Lander simulators, to a man
they all said later that the LLTV was the most realistic trainer. Neil
Armstrong went so far as to say on his return that the LLTV was so good at
simulating the lunar landing that he was entirely comfortable with what he
was doing when he made his actual descent to the moon that memorable day in
July 1969.
The second LLRV still resides at the Flight Research Center, now known as
the NASA Dryden Flight Research Center. Meant to go to Houston to train
Apollo astronauts as had the first LLRV and the three improved LLTVs, it
never left the center. Instead, it was cannibalized for parts to support the
training program at the Manned Spacecraft Center, now NASA's Johnson Space
Center.
The second LLRV underwent a partial restoration in the late 1990s for use in
filming of the television mini-series "From the Earth to the Moon" about the
Apollo program, and it is now an historical highlight during tours of NASA
Dryden.
For more information about NASA Dryden Flight Research Center and its
research projects, visit:
http://www.nasa.gov/centers/dryden
PHOTO EDITORS: High-resolution photos to support this release are available
electronically on the NASA Dryden web site at:
http://www.nasa.gov/centers/dryden/news/newsphotos/index.html
NASA Dryden Flight Research Center, Edwards, Calif. May 12, 2008
(661) 276-2665
RELEASE : 08-18
NASA at 50: Flight Research Center's LLRVs Led to Apollo Lunar Landers
By Christian Gelzer, Tybrin Corp.
Chief Historian, NASA Dryden Flight Research Center
EDWARDS, Calif. -- President John F. Kennedy's 1961 challenge to put a man
on the moon and return him safely to Earth by decade's end electrified much
of the country, but it floored most NASA engineers.
Not that going into space was a new idea to engineers at NASA, or its
predecessor, the National Advisory Committee for Aeronautics. NACA engineers
had been discussing putting humans into space since the early 1950s. But
contemplating orbital flight is not the same thing as planning for an
excursion to the moon's surface.
Interestingly, two organizations were simultaneously thinking about the same
thing: regardless of what vehicle NASA settled on to get to the moon,
astronauts would need something to simulate, here on Earth, the descent to
and landing on the moon. The two organizations were NASA's Flight Research
Center at Edwards, Calif., and the Bell Aircraft Corp. in Niagara Falls,
N.Y.
Among the challenges was simulating the moon's gravity, which is only a
sixth of Earth's. How, in the early 1960s, are you going to do this with a
wingless aircraft? What method will you use to negate five-sixths of the
Earth's gravitational pull in flight? How will you compensate for the fuel
you burn off while in flight? (Keep in mind the state of computing in 1962,
and especially, of portable computers.)
And how are you going to reproduce the moon's lack of atmosphere right here
on Earth? Flying in a vacuum is quite different from flying in an
atmosphere, more different that you would expect, as the astronauts later
attested. Even small wind gusts will affect a simulation like the one in
question.
What NASA and Bell came up with was the Lunar Landing Research Vehicle, or
LLRV. The LLRV -- quickly dubbed the Flying Bedstead -- was powered by a
General Electric CF-700, the fan-jet version of the J-85 engine, mounted
inside two gimbaled rings. The dual gimbals enabled the engine to provide
true vertical thrust -- perpendicular to the Earth's surface -- while
allowing the rest of the vehicle to rotate freely in pitch and roll.
Eight thrusters were fixed to the frame as lift rockets, capable of
producing 500 pounds of thrust each. These were used for lift when flying a
lunar landing simulation.
For maneuvering, the engineers chose 16 smaller thrusters, four at each
corner of the vehicle. These were fired in pairs, one up and one down at
opposite corners of the vehicle. Half of the 16 thrusters were adjustable on
the ground to vary their output from 18 to 90 pounds thrust so engineers
could experiment to find which setting was best suited for training.
The craft carried two fuels: JP-4 for the jet engine and hydrogen peroxide
for the thrusters. The hydrogen peroxide was a 90 percent pure solution, and
was pressurized with helium to ensure a constant flow to the thrusters.
Bell delivered the first LLRV to the Flight Research Center in the spring of
1964. The second vehicle followed not long after. Ground tests began once
the first vehicle was uncrated and assembled, and in October of that year
Joe Walker, the center's chief pilot, took the LLRV up for its first flight.
The CF-700 engine could produce 4,200 pounds of thrust under ideal
conditions, barely enough for a thrust-to-weight ratio of 1.05 to 1.
Perhaps more remarkable than anything else about it, the LLRV was a
fly-by-wire aircraft -- one of the very first -- controlled by three analog
computers. There was no mechanical backup control system of any kind,
primarily because of weight considerations.
In preparation for the first flight the vehicle was towed to South Base at
Edwards and covered with two tarpaulins. That night it snowed and when the
crew arrived the next day there were eight inches of snow on the vehicle.
The flight tests at the Flight Research Center convinced NASA that the LLRV
was a viable training tool, and the agency contracted with Bell for three
additional vehicles. Built according to modifications made at the Flight
Research Center to the two LLRVs, the three new vehicles were dubbed Lunar
Landing Training Vehicles, or LLTVs.
Although the Apollo astronauts used other Lunar Lander simulators, to a man
they all said later that the LLTV was the most realistic trainer. Neil
Armstrong went so far as to say on his return that the LLTV was so good at
simulating the lunar landing that he was entirely comfortable with what he
was doing when he made his actual descent to the moon that memorable day in
July 1969.
The second LLRV still resides at the Flight Research Center, now known as
the NASA Dryden Flight Research Center. Meant to go to Houston to train
Apollo astronauts as had the first LLRV and the three improved LLTVs, it
never left the center. Instead, it was cannibalized for parts to support the
training program at the Manned Spacecraft Center, now NASA's Johnson Space
Center.
The second LLRV underwent a partial restoration in the late 1990s for use in
filming of the television mini-series "From the Earth to the Moon" about the
Apollo program, and it is now an historical highlight during tours of NASA
Dryden.
For more information about NASA Dryden Flight Research Center and its
research projects, visit:
http://www.nasa.gov/centers/dryden
PHOTO EDITORS: High-resolution photos to support this release are available
electronically on the NASA Dryden web site at:
http://www.nasa.gov/centers/dryden/news/newsphotos/index.html