10 Going for Broke
That sudden notification gave me an urgency to
immediately try and complete expansion of the
envelope with guts, not gray matter, as Chuck’s
flights were imminent and I was starting to check
him out. My zoom flights were at an end and
methodically expanding the zoom envelope would
not be possible.
I had expected much more than my 40-day Air
Force test program for something of such unique
proportions. Under normal circumstances a period
of a year would have been brief. My plan to
gradually increase the pull-up g and climb
angle, and find the optimum was dead: That
traditional approach to testing that Chuck
Yeager used successfully in X-1A. It was obvious
the ASTs were moving to the school.
I threw caution to the wind, a very stupid
decision in our business and decided off the top
of my head, or maybe closer to my butt, that I
would start at Mach 2.4 and climb at 85-degrees
of pitch to 100,000 feet and then lower pitch
angle to 70-degrees until reaching the parabolic
path at 16 degree alpha, then fly a typical path
to the apogee. I felt that if I went the full
distance at 85 degrees I would not have the
control power with RCS to rotate 170 degrees
over the top to descend safely, necessitated by
an 85 angle. I knew I was stretching, but was
convinced, or maybe more correctly had hoped to
have enough speed left at 100k to lower the
actual climb angle to 70 and then intercept the
16-degree angle of attack, at which point my
instruments would allow me to control the space
portion over the peak with the reaction control
system, with the standard techniques.
Up to that intersect point I was knowingly
without any indication of how rapidly I was
losing energy and how much margin I was losing.
If I had approached this logically, a 75-degree
angle might have been prudent, but 85 was
illogical because I had to presume enough
dynamic pressure would remain to actually
lower the flight path by at least 15 degrees,
not just the nose angle. In retrospect, I had
chosen an impossible profile and should have
realized that before I experienced it.
Looking back, Mother Nature had alerted me this
was too extreme, when I got less than 2%
increase in altitude with a 10% increase in Mach
on my highest zoom. The urge to find the maximum
in one flight had robbed me of common sense, if
I had any, and not only erased judgment, but
also overrode experience.
I proceeded as planned but when I tried to lower
the nose of the airplane at 100,000 I wasn’t
able to get down to the 70-degree climb angle.
I had used up so much energy in the extended
pull-up and climb that I literally fell
backward, then tumbled and rolled, falling from
somewhere above 100,000, I don’t remember the
exact peak any longer, although I checked it
when I reviewed the radar ground track and the
altitude plot after that mission.
The plot showed the usual run-in from the
Pacific Ocean
toward the east and pull- up as planned to
perform the easterly zoom north of the base. We
used this direction to convert energy of
westerly tail winds into potential energy (added
height) and position ourselves for a short
return to base and a possible dead stick
landing. The track showed nearly vertical,
consistent with the AARS gage. The flight path
topped out and came almost straight down, of
course. What goes up, must come down, was about
the only thing that didn’t surprise me on that
flight.
That little pen on the ground radar system may
have seen a nearly straight line down but the
fall I was in was nothing like that. The
airplane was out of control, with random motion
in all three axes. I had intentionally flown
through a tumble in the T-33, but I could look
around and see the ground most of the time, and
knew what to expect. Restricted by my view from
the fixed hard helmet of the suit, I could only
be oriented and get some sense of motions during
the periods when the nose was toward the
ground. At other times I saw only sky and had
an inexact sense of the airplanes motions,
between flips and rolls toward terra firma.
This motion was far outside the use of flight
instruments, something like recovery of motion
on the Euler angle control simulator, which was
very difficult in school at ARPS. As I was
trying to put the puzzle together and counter
the motions, attempting to combine both RCS and
aerodynamic controls, one thought plagued me.
Could the airplane fall fast enough that I would
have a major structural failure as I hit denser
atmosphere? If so, haste in recovery was
vital.
All I could do was to keep trying to incorporate
both flight control systems in my efforts to
stop the motion. Once stopped, in any nose
down attitude I had a chance to fly it out of
the problem.
After a period of time, I got the motion stopped
but I was inverted …… and falling upside down,
at a steep dive angle. Were I to pull through,
like the finish of a loop, I would significantly
increase the rate of descent and heat load on
the canopy and airplane. I knew that staying
inverted in a steep dive would be worst of all,
so my only option was to try rolling out to an
upright dive, before pulling out. If
successful, I would be situated near a normal
zoom recovery dive.
I applied roll controls and the airplane
suddenly went out of control again. I can only
surmise that I got coupling between the axes, or
maybe gyroscopic coupling from the jet engine
rotations, or perhaps merely by roll-coupling at
high Mach, into an excess alpha. Fortunately,
the out of control fall helped to slow the
speed. Once again I reacted to the motion at
each point in time, finally got it stopped, this
time where I could fully recover. The rest of
the descent was uneventful.
One thing the little pen drawing on the radar
plot and I agreed on was that from a zoom
heading east I had finally come to my pull-out
headed only slightly south of a westerly path,
and had invented a new acrobatic maneuver I
didn’t understand, and never wanted to
duplicate.
The thing that makes my pre-flight decisions and
plan on that flight so incomprehensible now,
even with diminished cognizance of
age 75, is that I knew I would be outside the
cockpit indication limits necessary to maintain
control during ascent until well above 100,000
feet. This plus engineering judgment should have
limited me to no more than 75 degrees. I gave
the AST no chance from the start!
Actually, my test program had a blessing and a
penalty wrapped up in one. The Flight Test
Center had no compelling attachment with the
program and no operational command watching over
us. Us, in this case were only the ground crew
and one young 2nd lieutenant, who was
assigned as test engineer, his first job and our
only technical asset, which meant he couldn’t
assist. He had a civilian boss, Clendon
Hendricks, but Clen seemed to have little
interest in us until a critical event, soon to
occur, changed the history of the AST.
There was no way the lieutenant could analyze
flight data from a flight within weeks, if he
could at all, so there was no effort made, and
my only learning process was what I saw and felt
in flight.
I feel the AST might have had another 1000 feet
in it, under ideal weather conditions and with
optimum zoom angle, not much more.
Up to that point, the School did not chose to be
involved with activity under the auspices of the
Test Operations, as it was then and according to
many, has never changed. And very little
attention was paid to my tests by operations.
Therefore, except for a couple of radar site
workers, who gave me the plot and had no concern
with it, no one on base was aware my 85-degree
experiment even took place. Only friends I
chose to confide in after I left Edwards, had
known until now. It’s not that I hid it for the
sake of pride, as I’ve done too many goofy
things flying to try hiding them, as you’ll
find out if you choose to read my autobiography
on this web site (to be coming in installments,
soon).
I guess if anything good came out of that
flight, I did use what I learned on this flight
to reinforce my knowledge and respect of the
control task over the top and used the
experience I had gained, as much as he would
listen, for Chuck Yeager in briefing him on how
to reserve energy for his zooms, soon to come.
Not long ago, I watched a program on Discovery
Wings (which interviewed Col. Harold “Tom”
Collins, our Test Operations Chief during AST)
about when he and Chuck Yeager flew in the North
Korean Mig-15 that was delivered by a defector.
He told about being unable to dive it to
supersonic because it would shake, vibrate and
climb as it approached Mach 1, but they could
never push it through. Tom complimented Chuck
on having the guts to roll inverted and dive to
attempt it, which was extremely bold.
Chuck Yeager's career was loaded with
demonstrations of fearlessness and self
confidence that few others possess. My
favorite is his pushing the X-1A beyond its
anticipated Mach 2 limit. He took it to
2.5 Mach before it tumbled out of control and
fell for more than 40,000 feet before he
recovered. |