Back-Home | U2 - Project Management | ||||||||
|
High Flight
by Barry Schiff (Retired TWA Captain and author)
Maj. Dean Neeley is in the forward,
lower cockpit of the Lockheed U-2ST, a two-place version of the
U-2S, a high-altitude reconnaissance aircraft that the Air Force
calls "Dragon Lady.." His voice on the intercom breaks the silence.
"Do you know that you're the highest person in the world?" He
explains that I am in the higher of the two cockpits and that there
are no other U-2s airborne right now. "Astronauts don't count," he
says, "They're out of this world."
We are above 70,000 feet and still
climbing slowly as the aircraft becomes lighter. The throttle has
been at its mechanical limit since takeoff, and the single General
Electric F118-GE-101 turbofan engine sips fuel so slowly at this
altitude that consumption is less than when idling on the ground.
Although true airspeed is that of a typical jetliner, indicated
airspeed registers only in double digits.
I cannot detect the curvature of the
Earth, although some U-2 pilots claim that they can. The sky at the
horizon is hazy white but transitions to midnight blue at our
zenith. It seems that if we were much higher, the sky would become
black enough to see stars at noon. The Sierra Nevada, the
mountainous spine of California, has lost its glory, a mere
corrugation on the Earth. Lake Tahoe looks like a fishing hole, and
rivers have become! rivulets. Far below, "high flying" jetliners
etch contrails over Reno, Nevada, but we are so high above these
aircraft that they cannot be seen.
I feel mild concern about the bailout
light on the instrument panel and pray that Neeley does not have
reason to turn it on. At this altitude I also feel a sense of
insignificance and isolation; earthly concerns seem trivial. This
flight is an epiphany, a life-altering experience.
I cannot detect air noise through the
helmet of my pressure suit. I hear only my own breathing, the hum of
avionics through my headset and, inexplicably, an occasional,
shallow moan from the engine, as if it were gasping for air.
Atmospheric pressure is only an inch of mercury, less than 4 percent
of sea-level pressure. Air density and engine power are similarly
low. The stratospheric wind is predictably light, from the southwest
at 5kt, and the outside air temperature is minus 61 degrees Celsius.
Neeley says that he has never
experienced weather that could not be topped in a U-2, and I am
reminded of the classic transmission made by John Glenn during Earth
orbit in a Mercury space capsule: "Another thousand feet, and we'll
be on top." Although not required, we remain in contact with Oakland
Center while in the Class E airspace that begins at Flight Level
600. The U-2's Mode C transponder, however, can indicate no higher
than FL600. When other U-2s are in the area, pilots report their
altitudes, and ATC keeps them separated by 5,000 feet and 10 miles.
Our high-flying living quarters are
pressurized to 29,500 feet, but 100-percent oxygen supplied only to
our faces lowers our physiological altitude to about 8,000 feet. A
pressurization-system failure would cause our suits to instantly
inflate to maintain a pressure altitude of 35,000 feet, and the flow
of pure oxygen would provide a physiological altitude of 10,000
feet.
The forward and aft cockpits are
configured almost identically. A significant difference is the
down-looking periscope/driftmeter in the center of the forward
instrument panel. It is used to precisely track over specific ground
points during reconnaissance, something that otherwise would be
impossible from high altitude. The forward cockpit also is equipped
with a small side-view mirror extending into the air stream. It is
used to determine if the U-2 is generating a telltale contrail when
over hostile territory. Considering its 103-foot wingspan and
resultant roll dampening, the U-2 maneuvers surprisingly well at
altitude; the controls are light and nicely harmonized. Control
wheels (not sticks) are used, however, perhaps because aileron
forces are heavy at low altitude. A yaw string (like those used on
sailplanes) above each canopy silently admonishes those who allow
the aircraft to slip or skid when maneuvering. The U-2 is very much
a stick-and- rudder airplane, and I discover that slipping can be
avoided by leading turn entry and recovery with slight rudder
pressure.
When app roaching its service ceiling,
the U-2's maximum speed is little more than its minimum. This
marginal difference between the onset of stall, buffet and Mach
buffet is known as coffin corner, an area warranting caution. A
stall/spin sequence can cause control loss from which recovery might
not be possible when so high, and an excessive Mach number can
compromise structural integrity. Thankfully, an autopilot with Mach
hold is provided.
The U-2 has a fuel capacity of 2,915
gallons of thermally stable jet fuel distributed among four wing
tanks. It is unusual to discuss turbine fuel in gallons instead of
pounds, but the 1950s-style fuel gauges in the U-2 indicate in
gallons. Most of the other flight instruments seem equally
antiquated.
I train at 'The Ranch'.
Preparation for my high flight began the
day before at Beale Air Force Base (a.k.a. The Ranch), which is
north of Sacramento, California, and was where German prisoners of
war were interned during World War II. It is home to the 9th
Reconnaissance Wing, which is responsible for worldwide U-2
operations, including those aircraft based in Cyprus; Italy; Saudi
Arabia; and South Korea.
After passing a physical exam (whew!), I
took a short, intensive course in high-altitude physiology and use
of the pressure suit. The 27-pound Model S1034 "pilot's protective
assembly" is manufactured by David Clark (the headset people) and is
the same as the one used by astronauts during shuttle launch and
reentry.
After being measured for my $150,000
spacesuit, I spent an hour in the egress trainer. It provided no
comfort to learn that pulling up mightily on the handle between my
legs would activate the ejection seat at any handle is pulled, the
control wheels go fully forward, explosives dispose of the canopy,
cables attached to spurs on your boots pull your feet aft, and you
are rocketed into space. You could then free fall in your inflated
pressure sui! t for 54,000 feet or more. I was told that "the
parachute opens automatically at 16,500 feet, or you get a refund."
I later donned a harness and
virtual-reality goggles to practice steering a parachute to landing.
After lunch, a crew assisted me into a pressure suit in preparation
for my visit to the altitude chamber. There I became reacquainted
with the effects of hypoxia and was subjected to a sudden
decompression that elevated the chamber to 73,000 feet. The pressure
suit inflated as advertised and just as suddenly I became the
Michelin man. I was told that it is possible to fly the U-2 while
puffed up but that it is difficult. A beaker of water in the
chamber boiled furiously to demonstrate what would happen to my
blood if I were exposed without protection to ambient pressure above
63,000 feet.
After a thorough preflight briefing the
next morning, Neeley and I put on long johns and UCDs (urinary
collection devices), were assisted into our pressure suits,
performed a leak check (both kinds), and settled into a pair of
reclining lounge chairs for an hour of breathing pure oxygen. This
displaces nitrogen in the blood to prevent decompression sickness
(the bends) that could occur during ascent.
During this "pre-breathing," I felt as
though I were in a Ziploc bag-style cocoon and anticipated the
possibility of claustrophobia. There was none, and I soon became
comfortably acclimatized to my confinement. We were in the aircraft
an hour later. Preflight checks completed and engine started, we
taxied to Beale's 12,000-foot-long runway. The single main landing
gear is not steerable, differential braking is unavailable, and the
dual tailwheels move only 6 degrees in each direction, so it takes a
lot of concrete to maneuver on the ground. Turn radius is 189 feet,
and I had to lead with full rudder in anticipation of all turns. We
taxied into position and came to a halt so that personnel could
remove the safety pins from the outrigger wheels (called pogos) that
prevent one wing tip or the other from scraping the ground. Lt. Col.
Greg "Spanky" Barber, another U-2 pilot, circled the aircraft in a
mobile command vehicle to give the aircraft a final exterior check.
I knew that the U-2 is overpowered at
sea level. It has to be for its engine, normally aspirated like
every other turbine engine, to have enough power remaining to climb
above 70,000 feet. Also, we weighed only 24,000 pounds (maximum
allowable is 41,000 pounds) and w ere departing into a brisk
headwind. Such knowledge did not prepare me for what followed. The
throttle was fully advanced and would remain that way until the
beginning of descent. The 17,000 pounds of thrust made it feel as
though I had been shot from a cannon. Within two to three seconds
and 400 feet of takeoff roll, the wings flexed, the pogos fell away,
and we entered a nose-up attitude of almost 45 degrees at a
best-angle-of-climb airspeed of 100 kt. Initial climb rate was 9,000
fpm.
We were still over the runway and
through 10,000 feet less than 90seconds from brake release. One need
not worry about a flameout after takeoff in a U-2. There either is
enough runway to land straight ahead or enough altitude (only 1,000
feet is needed) to circle the airport for a dead-stick approach and
landing.
The bicycle landing gear creates !
little drag and has no limiting airspeed, so there was no rush to
tuck away the wheels. (The landing gear is not retracted at all when
in the traffic pattern shooting touch and goes.) We passed through
30,000 feet five minutes after liftoff and climb rate steadily
decreased until above 70,000 feet, when further climb occurred only
as the result of fuel burn.
On final approach Dragon Lady is still
drifting toward the upper limits of the atmosphere at 100 to 200 fpm
and will continue to do so until it is time to descend. It spends
little of its life at a given altitude. Descent begins by retarding
the throttle to idle and lowering the landing gear. We raise the
spoilers, deploy the speed brakes (one on each side of the aft
fuselage), and engage the gust alleviation system. This raises both
ailerons 7.5 degrees above their normal neutral point and deflects
the wing flaps 6.5 degrees upward. This helps to unload the wings
and protect the airframe during possible turbulence in the lower
atmosphere.
Gust protection is needed because the
Dragon Lady is like a China doll; she cannot withstand heavy gust
and maneuvering loads. Strength would have required a heavier
structure, and the U-2's designer, Clarence
"Kelly" Johnson, shaved as much weight as possible-which
is why there are only two landing gear legs instead of three. Every
pound saved resulted in a 10-foot increase in ceiling. With
everything possible hanging and extended, the U-2 shows little
desire to go down. It will take 40 minutes to descend to traffic
pattern altitude but we needed only half that time climbing to
altitude. During this normal descent, the U-2 covers 37 nm for each
10,000 of altitude lost.
When clean and at the best glide speed
of 109 kt, it has a glide ratio of
28:1. It is difficult to imagine ever being beyond glide range of a suitable airport except when over large bodies of water or hostile territory. Because there is only one fuel quantity gauge, and it shows only the total remaining, it is difficult to know whether fuel is distributed evenly, which is important when landing a U-2. A low-altitude stall is performed to determine which is the heavier wing, and some fuel is then transferred from it to the other.
We are on final approach with flaps at
35 degrees (maximum is 50 degrees) in a slightly nose-down attitude.
The U-2 is flown with a heavy hand when slow, while being careful
not to overcontrol. Speed over the threshold is only 1.1 VSO (75 kt),
very close to stall. More speed would result in excessive floating.
I peripherally see Barber accelerating the 140-mph, stock Chevrolet
Camaro along the runway as he joins in tight formation with our
landing aircraft.
I hear him on the radio calling out our
height (standard practice for all U-2 landings). The U-2 must be
close to normal touchdown attitude at a height of one foot before
the control wheel is brought firmly aft to stall the wings and plant
the tailwheels on the concrete. The feet remain active on the
pedals, during which time it is necessary to work diligently to keep
the wings level. A roll spoiler on each wing lends a helping hand
when its respective aileron is raised more than 13 degrees.
The aircraft comes to rest, a wing tip
falls to the ground, and crewmen appear to reattach the pogos for
taxiing.
Landing a U-2 is notoriously
challenging, especially for those who have never flown taildraggers
or sailplanes. It can be like dancing with a lady or wrestling! a
dragon, depending on wind and runway conditions. Maximum allowable
crosswind is 15 kt.
The U-2 was first flown by Tony Levier
in August 1955, at Groom Lake (Area
51), Nevada. The aircraft was then known as Article 341, an attempt by the Central Intelligence Agency to disguise the secret nature of its project.
Current U-2s are 40 percent larger and
much more powerful than the one in which Francis Gary Powers was
downed by a missile over the Soviet Union on
May 1, 1960.
The Soviets referred to the U-2 as the
"Black Lady of Espionage" because of its spy missions and mystique.
The age of its design, however, belies the sophistication of the
sensing technology carried within. During U.S. involvement in
Kosovo, for example, U-2s gathered and forwarded data via satellite
to Intelligence at Beale AFB for instant analysis. The results were
sent via satellite to battle commanders, who decided whether attack
aircraft should be sent to the target. In one case, U-2 sensors
detected enemy aircraft parked on a dirt road and camouflaged by
thick, overhanging trees. Only a few minutes elapsed between
detection and destruction. No other nation has this capability.
The U-2 long ago outlived predictions of
its demise. It also survived its heir apparent, the Lockheed SR-71
Blackbird. The fleet of 37 aircraft is budgeted to operate for
another 20 years, but this could be affected by the evolution and
effectiveness of unmanned aircraft.
After returning to Earth (physically and
emotionally), I am escorted to the Heritage Room where 20 U-2 pilots
join to share in the spirited celebration of my high flight. Many of
them are involved in general aviation and some have their own
aircraft.
The walls of this watering hole are
replete with fascinating memorabilia about U-2 operations and
history. Several plaques proudly list all who have ever soloed
Dragon Lady. This group of 670 forms an elite and unusually
close-knit cadre of dedicated airmen.
|
||||||||
|