16 Yeager’s View,
In Review
The following are Chuck Yeager’s statements
from: ‘YEAGER, AUTOBIOGRAPHY’ by General
Chuck Yeager and Leo Janus, Bantam Books July
1985. That autobiography is a view of Brigadier
General Chuck Yeager’s life, with emphasis on
his flying career. The book includes a brief
section on his NF-104A, AST experiences and his
accident in which the airplane was lost after a
flat spin from which Yeager ejected and was
injured by fire.
The following discussion includes impressions or
opinions by Chuck Yeager in his autobiography
regarding his failure to achieve the record he
was attempting and his resultant crash in an
AST.
My summary of the issues Chuck addressed in the
reference section of his book serve as a lead
in, only if necessary for clarity and are in
standard print:
The Italics
are the words of General Yeager:
Reference: “Rescue Mission”, Pages
171-172: This section of the book addresses
Chuck Yeager’s lack of academic credentials
necessary by Air Force Regulations to fly
experimental test flights, which may give
insight into his never achieving maximum
performance in the NF-104 AST:
I had no shortage of enemies in flight test,
and one of them (I never learned who) discovered
that I had never completed the stability and
control course at the test pilot school. That
is, the school was in two parts. I finished the
first part, then went on to fly the X-1,
skipping the second part, stability and control
school, a six-month course. Without a diploma
from stability and control school, I could not
be certified to do flight testing. Well it was
ridiculous. I had more stability and control
experience than any of my would-be instructors…
… I had literally hundreds of hours of stability
and control work behind me when I was forced
back to school. General Boyd’s hands were tied;
regulations were regulations. I was sabotaged,
but it was ironic having the Air Force’s big
test pilot hero back in test pilot school,
hitting the books. ……The school was on base. The
instructors made damned sure it wouldn’t be easy
for me Their attitude was right out in the
open: they would love to flunk me. … So I did
what I was told and counted to three or four
hundred. But I always remembered those
nasty
sons of bitches. If they were harassing me
because of a cocky attitude or because I wasn’t
doing my work, I would respect that. But this
was spite. I put a little red flag next to the
name of each one of those guys, and nailed them
the first chance I got. That’s exactly what I
did, and ruthlessly, too. …Then an amazing thing
happened. General Boyd grabbed me out of school
and took me with him to
France. Wham, bam. One day I was in school
and the next day I was in a fighter crossing the
Atlantic.
The school’s commandant was a bird colonel. He
raised hell, saying I couldn’t miss three weeks
of school and expect to graduate.
When we returned to Edwards, the old man marched
on the test pilot school. The commandant told
him, “General, there’s no way we can pass
Yeager. He’s missed too much work.” The old
man handed him the stability and control reports
I had prepared on the XF-92 and the French
jets. “Study that,” he said, “you might learn
something. Yeager knows more about stability
and control than you can teach him: The
commandant said that might be, but rules were
rules, and I couldn’t get a certification
diploma without completing my course work. And
without the certificate my
test pilot days were over. General Boyd
turned red, then purple. He slammed his fist
down on the table and his voice shook that
room. “Goddamn it, I’m in charge of this
school. You will pass him.” And that’s how I
got my diploma.
Now that’s one heck of a tale, but anyone who
spent time in the military and has heard of the
power that General Boyd held, especially in
flight testing, would find it hard to imagine
any colonel took such direct opposition to his
commander, especially that general, under those
circumstances.
General Boyd, the most notorious and powerful
test pilot and “owner” Edwards base and Wright
Patterson before that and all folks in test, was
opposed by the school commandant? If he did
that, then he was principled, adamant and deeply
concerned about Chuck’s lack of technical
knowledge on stability and control. Gen. Boyd,
long deceased, is reported as saying it best, on
page 173, about Chuck as a great and natural
flyer, and of that I have no doubt.
Unfortunately, the AST above 100,000 feet in a
steep climb was no longer an airplane but became
a space vehicle, without the attributes Chuck
was inherently familiar and gifted to deal
with. That airplane demanded a full
understanding of space dynamics and control, not
just aerodynamics. Unfortunately, Chuck had only
the latter and that was more experienced and
intuitive than technical.
One serious consideration does arise. It is one
thing to understand why an aircraft possesses
certain stability and control, and the
conditions necessary for that. It is entirely
another to recognize and control it in flight,
but, without technical understanding and theory
you can do it only near the bounds you have
previously experienced. Chuck had neither the
technical background nor the prior experience in
this one case in his flying career to get so far
out of bounds.
I have no doubt accepting Chuck Yeager’s
vindictiveness to his instructors and those he
felt wronged him as he expressed it, because I
witnessed the same. He was fired from his job,
as the Deputy Director of Flight Test Operations
by his boss and mine, Colonel Clayton L.
Peterson, in 1962. From that day on, over the
years, he would vilify Peterson. On my last
extended visit with Chuck Yeager and Bud
Anderson, at the Air Force 50th
Anniversary Air Show he accused both Colonel
Peterson and his wife June of stealing
government funds. Knowing her for many years
until her death, and Pete over 40 years until
his more recent death, I revered them and I
would bet my life against that possibility, and
Chuck’s growing vitriolic attacks over the years
made a strong point in both their favor, but
‘that’s Chuck’, and I understood.
Reference: “Going For Another Record”
Page 278-283 “: This section of the Yeager
autobiography addresses his attempts to set a
world altitude in flying the NF-104A, AST, but
is chock full of misinformation, incredible
claims and invalid statements of the
capabilities and limitations of the airplane.
These quotes seem an effort to transfer
responsibility for the accident entirely to
anything but pilot error:
“High engine rpm being the only way to
recover a 104 out of a flat spin.”
There was no possibility of recovery for a
104 in a flat spin with the use of J-79 engine
power, period. According to analyses, it was the
limited rpm of the jet still turning, minutes
after he shut it down, which had the gyroscopic
effects and probably made the spin reverse
direction. He spun 3 normal, oscillatory spins
to the right before the aircraft reversed
direction into a flat spin, based on data from
the airplane’s recorder, which was recovered. A
flat spin was not unexpected with a high
horizontal tail, affected by downwash from the
wing at high angle of attack.
“Before our students began flying them (ASTs), I decided to
establish some operating parameters to learn at
what altitude the aerodynamic pitch-up forces
would be greater than the amount of thrust in
the hydrogen peroxide rockets installed in the
nose (2 x 250 lb. thrust).”
Every one of Chuck’s flights in the AST was
purely practice to try and establish a record,
nothing more or less. I assure you that by the
time he made his last flight he was struggling
just to achieve the profile and not doing any
testing! Not one shred of flight data was
analyzed during the entire Air Force test
program, including his flights until after his
accident, due to budget constraints on the
program, and the board president was in the line
of decision on those cost constraints, in his
primary assignment as the Deputy Commander of
Test Operations. The only data ever saved were
from the recorder in his crashed airplane, in
which every bit of data for his last two
attempts was saved.
For understanding of technical facts concerning
Chuck’s claims, please read the Space
Dynamics and Control section. Briefly,
altitude was not the most critical factor of
control power for the thrusters, but dynamic
pressure, a function of both density and
velocity squared. As density approached zero,
thrusters were more effective, and aerodynamic
controls became useless. Once aerodynamics
became nil, pitch-up disappeared with it. But
spare the poor jock who allowed angle of attack
above pitch-up to exist when he reentered the
high dynamic pressure flight regime, due to his
failure to properly maintain controls with the
RCS. That is precisely what happened to Chuck
Yeager, but his mistake happened in the area he
had spent his whole flying career in, the dense
atmosphere. Incidentally there was large margin
for error between the pitch-up angle and the
proper angle of attack for the zoom flight.
Surprisingly, Chuck’s statements show lack of
understanding of the classical aerodynamic
pitch-up in his claim, as well. The only way a
pilot can discern the pitch-up angle is through
very controlled testing, reference my Strake
Tests on a standard F-104, in the preceding
chapter on the rest of my tour at the
Flight
Test Center. The AST didn’t provide the pilot
with the vital instrument of calibrated angle of
attack, a necessity for such a test. It also
provided no visual angle reference of horizon,
only a sky, dead ahead. The AARS only provided
a reference to the optimum and far lesser alpha,
of 16 degrees. Such a test as he suggested was
absolutely impossible in a zoom, besides making
no sense.
“We thought we would encounter pitch-up
somewhere around 95,000 feet.”
I’m unclear who “We” was. I was the only person
working with Chuck at the time and I certainly
didn’t say that, because I understood pitch-up.
On Col. Yeager’s two flights of December 10,
1963, he had one purpose which was to learn how
to attain the highest altitude he could in his
effort to be able to establish an official world
altitude record. That record was his end-goal,
and he had failed in all of his prior attempts.
He tried for the maximum altitude on every one
of his zooms, and he had to be feeling some
desperation. I flew the same airplane he was
flying to almost 121,000 feet. There was no
intent or expectation to ever approach pitch-up,
which would negate any chance for a high
altitude, and entail great risk. The flight
recorder later proved his maximum altitude on
the two flights that day to be less than
104,000.
“By then I was climbing at a steep
seventy-degree angle,…”
The reason Chuck Yeager never achieved high
altitude was his failure to reach and hold the
steep climb angle in the early climb on all his
flights. From the start, in my briefings to
him, I stressed that quickly attaining
70-degrees and constantly maintaining it until
intercepting the optimum alpha of 16 degrees was
the most important thing to attain max altitude.
That took constant attention, since retrimming
to help was ill-advised because of the sudden
reentry and the danger of pitch-up at that
point. I reiterated those things before his
last flight, because we looked at his flight
profile of the ground stations tracking him on
the morning flight and could see him well below
70 after pull-up then increase to higher pitch,
not only detrimental to altitude, but a
dangerous departure because it degraded the
information provided in the cockpit, which was
based on assumed correct mission management.
After his accident, when data reduction was
completed (the first time on any of our
flights), I was told by the technical advisor to
the accident board, Maj. Arthur Torosian, that
Chuck had climbed considerably below 70 degrees
on both of his flights and would raise the pitch
angle higher as he approached the top of the
zoom. To do that was courting a big problem.
“…and the afterburner flamed out, oxygen-starved
in the thin atmosphere.”
Many previous zooms showed the afterburner would
continue to operate only to about 75,000 feet
and had to be continually retarded and finally
shut down by the pilot to avoid over-temperature
or damage could result. Furthermore, the main
jet was only good to about 86,000 and the same
process was necessary with the main jet engine,
after over-temperature was reached in minimum
idle, only 250 pounds per hour of JP-4, jet fuel
due to a special low idle, all due to the low
oxygen content of the rare air at altitude.
These were limits in all flights and had no
bearing on his accident.
“I went over the top at 104,000 feet, and as the
airplane completed its long arc, it fell over…”
The actual instrumentation from the crashed
airplane was recovered and all of the data saved
and evaluated. One thing the pilot never knew
until checking ground track was his actual peak
altitude. The airplane could never ‘fall over’
except by proper use of the nose-down thrusters
during ascent, over the apogee and through and
nose-down descent. It was a neutrally stable
spaceplane over the top, if you achieved high
altitude and would climb with the nose 70
degrees high and fall back in that same attitude
with a pilot that failed to rotate the nose over
with RCS, on schedule. Physics assured a
reentry alpha of minus 70 degrees if Chuck
completed no nose over. That is, a backward
fall just 20 degrees less than straight
backwards. It was necessary for the pilot to
rotate nose down nearly 140 degrees on any zoom
to avoid that!
“But as the angle of attack reached 28 degrees,
…”
There could be no way to know there was 28
degrees since the aircraft had only a null angle
of attack needle at pre-selected 10, 12 or 16
degrees and his was set at 16. That needle
only displayed the proximity to that selected
angle, but holding it on the cross-hairs was
accurate and sufficient, with such a large
margin between 16 and the pitch-up angle of 28
degrees. I presume he may have remembered
28 from the accident report, based on the actual
pitch-up data.
“…the nose pitched up.”
Just more, like above. A pilot saw nothing but sky
looking forward and it took a lot of confidence
even to take that first peek, but served no
useful purpose. Considering all the trouble he
was having flying the profile he sure as hell
had no time to even take a peek. Chuck’s
performance to that point should not have bred
confidence, but if he had it that view gave him
no information on attitude. Again, the AST
could not ‘pitch-up’, if it reached the low q of
a max zoom, until it fell back into atmospheric
pressure because of negligible dynamic pressure
(as low as 2 to 10 PSF).
Under the conditions Chuck put himself in, he
was fully backward with an alpha as high as 160
degrees when pitch-up occured at only 28 degrees.
He was only 20 degrees shy of falling backward
with his nose pointed straight up. At the top of the maximum
zoom of the AST, the dynamic pressure was so low
that aerodynamic induced motions were nil
(including pitch-up and they could readily be
overcome with the thrusters if a proper climb
angle had been maintained from pull up. But add
yaw induced by the spinning jet turbines to
Chuck’s mistakes and you had perfect spin
conditions.
“ That had happened in the morning flight as
well. I used the small rocket thrusters on the
nose to push it down. I had no problem then.
This time, the damned thrusters had no effect.
I kept those peroxide ports open, using all my
peroxide trying to get the nose down, but I
couldn’t.”
Data reduction by engineers proved that Chuck
luckily got away with almost the same thing in
the morning as the afternoon, but his luck
finally ran out. It was not news to any F104
pilot that flight controls would not overcome
full-blown pitch up and flat spin, in normal
atmosphere. Chuck was already falling backward
when he used the RCS constantly, at which point
they were incapable of correcting his serious
problem. If the attitude was not constantly
controlled with thrusters using information
presented by the crossed needles of the AARS
gage, of course, the aircraft could fall back
into the atmosphere where the thrusters became
useless.
Look at it more simply. If you pulled up the
AST or any F-104 to 70 degree pitch, lets say
starting at 400 knots and 10,000 feet, with full
power, held it and cut back to zero power and
continued to hold the nose up, there would be a
point where it would be too late to try to push
the nose over, with aero or RCS controls or
both. You would do exactly what Yeager did.
Fall backwards still at 70 degrees pitch but a
minus 140 degrees angle of attack, where no
airplane can fly; a good opportunity for
tumbling or for a flat spin to develop.
This is an explanation of Chuck’s flight, with
the low altitude to make the point intuitive.
But it really doesn’t matter how much higher it
is presumed just as long as it never got high
enough and continued fast enough in order to
stay outside atmospheric effects long enough for
the RCS to rotate AST through the necessary 140
degree nose-over before falling into the
atmosphere again.
“ My nose was stuck high, and the damned
airplane finally fell off flat and went into a spin.”
My first Maximum Zoom was successful to almost
119,000 feet in spite of miswired controls,
which proved conclusively that the AST had a
great deal of control power safety margin in its
design, with all three directions miswired to
100% error with each operation. In fact it was
designed with margin even with only half of the
thrusters functioning! I'm afraid Chuck was
again stretching for a scapegoat on his
accident, and it certainly wasn't the Reaction
Control System.
The data from both flights showed that he had
come perilously close on his morning flight
also, but fortunately, he had applied nose-down
thrusters before he fell back into the
atmosphere, probably because he had flown a
better and little steeper profile so made it as
much as 4000 feet higher and had more rotation
time to recover to a nose down attitude before
encountering pitch up.
Most probably, Yeager always had pulled up too
shallow to achieve the higher altitudes and
tended to raise the nose later, then waited too
late for the nose-down controls with the
thrusters, based on the data from the last two
flights and the lack of altitude on all his
zooms. In that last flight the data proved that
he had given up so much energy in low climb
angle before he finally got the nose up, that
the rocket motor was still burning as he reached
the top, giving him a false sense of still
climbing, when he was starting to fall backward.
The liquid rocket, with only 6000 pounds of
thrust could not stop a rapid backward slide of
the AST. He had not even come close to flying
the necessary profile for success of his
mission.
“The data recorder would later indicate that the
airplane made fourteen flat spins from 104,000
until impact on the desert floor. I stayed with
it through thirteen of those spins before I
punched out. I hated losing an expensive
airplane, but I couldn’t think of anything else
to do.”
Something else did occur which was drag chute
deployment at 17,000 feet in the spin. That act
demonstrated how well Chuck Yeager reacted under
great duress, once he was back in his element of
aerodynamic flight. It is notable that the spin
was completely stopped by the parachute and with
the airplane in a steep and oscillatory dive,
but the spin reinitiated when the chute was
jettisoned, shortly before Chuck ejected, at
7000 feet.
Speaking about the bail out, landing and
recovery Yeager says:
“I was dazed,
standing alone on the desert, my helmet crooked
in one arm, my hand hurting so bad that I
thought I would pass out. My face didn’t hurt at
all. I saw a young guy running toward me; I had
come down only a mile or so from Highway 6 that
goes to Bishop out of Mojave, and he watched me
land in my chute, then parked his pickup and
came to offer his help. He looked at me, then
turned away. My face was charred meat. I asked
him if he had a knife. He took out a small
penknife, unfolded the blade, and handed it to
me. I said to him, “I’ve gotta’ do something
about my hand. I can’t stand it any more. “ I
used his knife to cut off the rubber-lined
glove, and part of two burned fingers came off
with it. The guy got sick. Then the chopper
came for me. I remember the medics running up.
I asked them, “Can you do something for my hand”
It’s just killing me.” They gave me a shot of
morphine through my pressure suit. They
couldn’t get the suit off because it had to be
unzipped all the way down, and then I’d have to
get my head out through the metal ring, but my
face was in such sorry condition that they
didn’t dare. At the hospital, they brought in
local firemen with bolt cutters to try to cut
that ring off my neck. It just wouldn’t do the
job. Finally, I said, “Look in the right pocket
of my pressure suit and get that survival saw
out of there. It was a little ring saw that I
always carried with me, even on backpacks, and
they zapped through that ring in less than a
minute.”
I was very impressed ever since that day with
how lucid Chuck was when our Flight Test H-21
helicopter, in which test pilot Phil Neale and I
picked him up from the desert floor, standing
next to the airplane’s hulk. Chuck talked to me
about the accident as we flew back to the base
hospital. But Chuck Yeager might have been in
shock then and I couldn’t tell it, or has lost
his memory since, because those are not the
facts. Bud Anderson did fly over Chuck long
enough to see him land safely, then Bud had to
return to base on low fuel, a fact Bud stated in
Chuck’s autobiography. At the moment I heard
him announce he went into his spin, Phil Neale
and I ran to the H-21 chopper kept outside the
Operations Center for such purposes.
We heard Bud Anderson radio that he saw Chuck
land safely in the chute and Bud was leaving for
home, because of fuel. We approached, shortly
thereafter to see Chuck standing close to his
airplane.
Ours was the only helicopter available to pick
Chuck up and Phil landed us at the helipad by
the hospital, where the medics saw Chuck, for
the first time. They may have given him the
pain killer injection then and his memories
could well have been the ravages of stress and
pain, and he obviously had both. But, he talked
in detail with me about the accident experience
in about 30 minutes alone in the back of the
chopper in route to the hospital.
The same was true of Chuck’s reporting a young
traveler, because we were there too close behind
Bud for that to have occurred and, when I recall
how critically burned Chuck appeared to me, I
know that no man would have driven away and left
him alone like that. Also, we would have seen
tracks and dust from a vehicle in that open
desolate desert, from miles away on our
approach, and Bud would have seen him. Bud just
smiles at the mention of that young fellow.
Do I think Chuck Yeager fabricated an excuse for
his event over the top and the resultant failure
in his accident? Undoubtedly, he did. It is
possible it was due to confusion by events to
which he could not relate, or to merely salvage
his image of invincibility. Here was a pilot,
one of the best stick and rudder flyers and
practiced test pilots, one of the most intuitive
in responding to the unknown events of flying
for all time who found himself in an
environment, in his mind, which is something
that he has contended with and conquered for so
many years. But he had not accepted from all
our briefings that it was not that same
environment, and skills to conquer it were
different. The AST responded in a ways
different than any airplane because of a
different environment. But little did I expect
that it would be his failure to control climb
angle in the environment that he understood so
well that would be his downfall. Chuck will never comprehend what
happened so cannot analyze it except on his
terms.
But there is that other
possibility, stated in the words of one of his
long time associates and competitors in flight
testing, the famous and first X-15 test pilot A.
Scott Crossfield, who I expect read Chuck’s book
and, in Scott’s recent speech at the Hiller
Museum in Santa Clara, CA, he referred to Chuck
Yeager as, “That well known novelist.”
Well, I have seen a long line of actions by
Chuck Yeager to polish and expand his the image,
and that not only fed his ego but his bank
account. But the one that impressed me
personally, was the fact that at a time when his
image needed a boost more than ever since his
famous Mach 1 flight, I was replaced in my only
opportunity to establish a record, by him, who
held so many records in the past that the Air
Force issued the regulation denying any pilot
more than one record unless made on the same
flight or project. And at that exact space of
time he was in close contact with three powerful folks
who possessed the means to assure he got it.
I stand with Scott Crossfield’s opinion, and
know the evidence is too powerful to doubt it.
Sadly, Chuck’s selection for the task, without
proper testing, was a disservice to both him and
the folks who created a unique airplane that had
the opportunity to develop capabilities that
have since been overlooked for almost four
decades.
Throughout, I have mentioned engineering whiz
Bob Hoey and his expert knowledge of the AST
along with the board developments and
investigations. I recently asked Bob to
reminisce about the program, especially his
conclusions about it.
From an engineer’s point of view, I would never
challenge Bob, I have seen him at work! From a
pilot’s standpoint, I would only disagree
slightly on one point he makes. I do not
believe that the AST would have been too
difficult for astronaut candidates, if they were
engineers as well as proven experienced test
pilots.
THE NF-104A AEROSPACE TRAINER; IN RETROSPECT
by Robert G. Hoey
“The
NF-104A was conceived as a low cost means of
exposing astronauts-in-training to the real
space environment, including some of the
required subsystems and flight control systems.
A modification to Lockheed's F-104 appeared to
be a reasonable way to do this. The NF-104A did,
in fact, include subsystems that were necessary
for space flight, and did, in fact, enter the
true space environment for a short time period.
The airplane performed as designed, a tribute to
the Lockheed design team and the flight test
community.
The
potential use of the airplane in a training
mode, however, was questionable due to the short
exposure time and the high risk associated with
each flight. It was a single-seat aircraft,
which meant that there was no instructor
available to correct errors or bad decisions by
the student.
Additional information obtained during the test
program further degraded the airplanes potential
as a trainer, especially with regard to the
handling qualities. Aerodynamic controls are
approximately rate-command; that is, a
particular stick deflection will produce a roll
rate. Reaction control rockets, as used in the
space environment are acceleration-command; that
is, a particular stick deflection will produce
roll acceleration. The piloting technique is
quite different between the two systems. Smooth,
proportional commands are used for aerodynamic
controls, while short, pulse commands must be
used for reaction controls. There is a third
control method, used in some space vehicles,
which uses the characteristics of a spinning
mass (gyroscope) to change the attitude of the
spacecraft. When a torque is applied to the
gyroscope, the attitude changes in a direction
90 degrees from the applied torque (an applied
torque in pitch will produce yaw).
The
NF-104A transitioned from the aerodynamic
control region into the space control region and
back in less than 1 minute. The student pilot
had to adapt, and transition from aerodynamic
controls to reaction controls and back again,
within this time. He also had to simultaneously
perform a very large change in pitch angle to
realign the airplane for entry using some
combination of the two control features. Failure
to perform this alignment could result in a deep
stall condition as encountered by Gen. Yeager.
The discovery during the test program of
significant gyroscopic effects from the spinning
engine during this same critical time period
complicated the piloting task even more since
the application of the required nose-down pitch
control input caused a gyroscopic yawing
response in the airplane.
Performing a successful zoom maneuver in the
NF-104A was a very demanding task - probably
more demanding than any of the maneuvers that
might be required in an actual space vehicle.
Limiting
the climb pitch angle served to maintain a
higher level of aerodynamic control over the
top, but, of course, that tended to defeat the
available reaction control training. Several
efforts were undertaken to try to maintain
higher engine rpm over the top to allow for more
reliable engine restarts after entry. These
efforts would tend to amplify the rather
confusing gyroscopic effects. Braking the engine
after shutdown would have eliminated the
gyroscopic effects as a complicating factor, but
would have resulted in dead-stick landings after
every zoom mission.
In retrospect it appears that the NF-104A
airplane and subsystems performed as designed
and did, in fact, produce a valid space
environment for a short time. The necessary
piloting tasks to safely control and recover the
vehicle, however, tended to detract from the
training aspects, and probably were more risky
and demanding than was appropriate for student
astronauts.”
|