3 Joint Test
Program
Traditionally, the contractor’s pilots flew
these with a smaller share by the Air Force
pilots. Usually it was an extended test
project. The AST’s contractor testing was
traditional in principal but very limited in
scope and duration, less than 4 months, which
addressed only the peculiar systems and
performance ranges of it. The first flight in
the JTP was flown on
9 July 1963
and the last on
24 October 1963. The austerity of the project was
especially evident in this and even more
truncated in the ensuing Air Force testing.
Jack Woodman was responsible for this testing at
their factory located on Palmdale Airport until
the aircraft were accepted for delivery by the
Air Force, with me flying a limited share. The
plan was to demonstrate the normal flight
performance of the AST, compared to a F-104
fighter on one AST. Then expand the AST’s
design envelope to the maximum zoom mission on a
second bird. Upon satisfactory performance and
acceptance of the project, I would fly the
airplanes to Edwards and expand the envelope and
fully qualify the AST for training operations,
during the Air Force testing, before turnover to
ARPS.
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60756 in-zoom |
The dynamics testing on the first airplane
(#60756) involved 18 flights to check critical
stability points of the AST remained generally
within the normal F-104 operating regimes. This
was deemed an acceptable trade against cost of a
major test program, to correlate AST performance
to all existing data from the extensive F-104
flight tests. Jack flew first on July 9
1963 and these tests topped out at Mach
2.2 with full rocket motor thrust, in level
flight. I flew a couple of them to get a feel
for the airplane. The maneuvering was limited,
because pulling g’s diminished dynamic stability
at high Mach number, and loss of dynamic
stability under such conditions is a one time
experience, fatality being the probable
outcome. The test point did provide some
margin, nevertheless. I would later expand my
tests to reduce this restriction.
Concurrently, we both flew the unique AST
performance, and envelope expansion tests on the
second aircraft (#60760). He made the usual
initial functional test flight on 10 Aug,
including stalls to compare with the standard
airplane. Thus began a series of dynamic
stability flights, at increasing Mach numbers
and attitude variations. I made my initial AST
flight in this airplane, its fourth flight, Mach
2 stability test on the way to the planned limit
of 2.2 mach at 3.5 g, for maximum performance
missions.
Jack began functional testing of the unique
systems on the reaction controls (RCS) on
its 3rd test flight, though not very
definitive until using it in full performance.
He fired the liquid rocket motor on its 4th.
I flew this aircraft next; my first use of the
RCS thrusters and liquid rocket. The thrusters
maintained impulse for the duration of the
commanded input, but with the airspeed in the
atmosphere had minor, temporary effect on the
airplanes motion, which was to be expected.
These thrusters would be the sole means of
control when zoom flights exceeded the limits of
aerodynamics, and only on that first and
critical maximum performance zoom, would we be
certain.
I was surprised with the smooth but significant
acceleration of the rocket motor, which felt
like a perfect fluid drive, compared with the
jolt when lighting an afterburner. The smooth
increase of thrust in the controllable range of
50 to 100% of rocket thrust was noticeable but
proved to be of little use during a maximum zoom
maneuver, where, not only jet and afterburner
were 100%, but the rocket, even at light-off,
was “throttle to the wall”.
23 Sept, Jack’s 19th flight, he flew
the first AST low zoom and topped out at 89,600
feet, intentionally climbing at a much lower
angle than the theoretical optimum angle of
70-degrees.
I made my first zoom, my fourth AST flight, two
days later. Climbing at a low angle, about
40-degrees, I reached 88,000 feet, not much over
my ARPS zooms in a standard 104 but it provided
me a chance to use the systems and displays.
According to a note in charts of the Woodman
biography, I encountered problems with control
on this flight, due to incorrect wiring of the
RCS system. My memory is vivid of that event and
it happened not on this but my succeeding
flight, where I will describe it. In fact, it
would hardly have been noticeable at this low
altitude climb.
On the 26th, Jack raised his altitude
to 97,500 feet with another increase in climb
angle. Starting on 4 October through the 10th,
Jack continued gradually increased climb angle
zooms to 102,000, 106,000 and 106,500,
respectively. These flights were at increased
climb angle, but remained within the capability
of the airplanes aero flight controls. The
zooms were still at high enough dynamic pressure
and corresponding low climb angle not to require
the RCS to maintain control and assure a safe
return.
Jack had to abort the first scheduled maximum
zoom on the morning of the 21st, due
to a malfunction of his pressure suit, an
unusual occurrence, unrelated to the airplane.
On that same afternoon, Jack made another
successful zoom to 109,000 feet, implying to me
something less than the maximum climb angle,
once again. Jack had wisely been creeping up on
the angle, as I expect he was directed to do. |