shafer@elxsi.dfrf.nasa.gov (04/14/89)
From: shafer@elxsi.dfrf.nasa.gov
Bill,
First, let me give you a little background. I'm a senior aerospace
engineer at the NASA Ames-Dryden Flight Research Facility (ADFRF).
ADFRF is located at Edwards Air Force Base, in the Mojave Desert of
Southern California, hence the references to the lakebed. I work in
flying qualities and stability and control. Subtopics include agility,
high-alpha maneuverability, displays, and handling qualities task
definition. I've also done a lot of flight test planning and test
management. Most of our aircraft are fighters, so most of my work has
been done on high-performance aircraft. I've also worked on the
Shuttle, the YF-12s, lifting bodies, and the X-29.
I have flown in a TF-104G, the USAF/Calspan NT-33A Variable Stability
Aircraft, the Calspan Lear 24 In-Flight Simulator (twice), and the
F-4E. I have also flown in a variety of other test aircraft and on
chase missions. I attended the National Test Pilot School's Flight
Test Engineering Short Course. I've flown the Vertical Motion
Simulator at Ames Research Center, both as a helicopter and as a
Harrier (YAV-8B). Except for the F-4 flight, which was provided by the
Air Force, all of this has been sponsored by NASA. I've also flown
Paris-New York on Concorde, back when the the dollar was _very_ strong
against the franc.
I met the Air Force officer that nominated me for this F-4 flight a
couple of years ago, when I was helping some USAF Test Pilot School
students with their senior project. I have worked with the TPS several
times--we finished a joint project a couple of months ago.
There wasn't enough time for me to go back through the altitude chamber
and update my card before the F-4 flight (I had the three-day course in
'81, before my F-104 flight, but this has expired) so our ceiling was
18,000 ft MSL. I'm going to try to go back through the chamber fairly
soon, since I might be able to wrangle a ride on a tanker and they
usually operate at 20,000-22,000 ft MSL.
Here's my report, ostensibly written for my supervisor but really
written for myself, so that I wouldn't forget the important points.
For this reason, it rambles a little.
F-4 Flight Report
On 5 December 1988, at the kind invitation of AFFTC, I flew in an F-4E,
tail number 660284. This aircraft was used by the Thunderbirds until
F-4s were replaced with F-16s. This aircraft still has the smoker and
inverted-flight fuel system. It has also been modified for use in
chasing cruise missiles. The pilot was Major Mike Costigan of the
6512th Test Squadron. The flight lasted 1.2 hr. Our call sign was
Rick 37. The jet was clean except for a centerline drop tank.
The crew brief included discussion of the flight cards, review of
egress and NORDO procedures, and definition of the section takeoff and
formation flight.
The flight started with a section takeoff with another F-4. We then
flew formation in moderately maneuvering flight for 5-10 min. Judging
by the motion of the stick, this is quite a high workload task. It was
really magic to see, with the other F-4 appearing to be motionless
relative to us with the ground moving beneath it. I took some pictures
of this but only a video or movie could really do it justice.
After we left the other F-4 Mike demonstrated the aircraft response to
control inputs with and without augmentation, gear up and down. The
aircraft has a fairly well-damped response gear up, augmentation on.
With the augmentation off, the aircraft is poorly damped and the dutch
roll mode is quite uncomfortable. When the gear is down and the
augmentation is off the aircraft is neutrally stable or slightly
unstable in pitch. Also, the dutch roll mode becomes essentially a
pure roll mode. I flew the aircraft in all of these cofigurations. We
then went to high alpha (over 19 units) and _very carefully_ looked
at the near-stall characteristics of the aircraft. It exhibited a
pitchup at which point we promptly put the nose down. The onset of
buffet was very marked.
Next we did some low level navigation, flying up the Kern River valley
at 500 KIAS, well below the surrounding terrain. This was quite
breathtaking. It's really something to look up and watch the ground
whizzing by. My forward visibility was nil and I had to look out the
side, which accentuated the effect. We pulled up out of the valley and
flew over Mt. Whitney, into the Owens Valley.
At this point Mike let me fly it again. He had described the F-4 as
flying as if it were balanced on the head of a pin and I found this to
be a very apt description. I had to reduce my gain drastically to even
begin to trim. I would barely get the jet wings-level and then arrest
my climb or descent, by which time I had one wing down, so around I'd
go in this loop. I finally got the roll trimmed out but I only managed
to slow the rates in the pitch axis.
After this, we dropped down and flew low across the Owens Valley and,
as we approached the mountains on the eastern side, Mike put it in
burner and we accelerated straight up, doing a 360 deg roll out at the
top of the climb. _WOW!_
Once we rolled out at 18,000 ft MSL, Mike gave me the aircraft again.
It was easier for me this time. I wasn't very good at staying level in
the first couple of turns as I didn't pull hard enough, but I finally
started cranking it around at 3-4 g, so we weren't falling out of the
sky. I didn't mess with the throttle as I was pretty much saturated
with just two axes. I also did several aileron rolls. On the first
one I got inverted and was so entranced at seeing the ground overhead
(underhead?), that Mike had to tell me to keep rolling. When I rolled
with g's on I could feel the lightening as this coupled.
Mike then took the aircraft back and we went to the tanker. This was
one of the things that I most wanted to do and we were very lucky to
have a tanker available. There we sat, perfectly stable, right behind
the tanker, and it looked like the boom was flying right at me since
the receptacle is just behind the aft cockpit. Again, judging by the
motion of the stick this was a very high-gain task, although this was
not apparent if I only watched the tanker. It was rock-steady. Mike
said that it was quite easy for him unless he had gone some time
without doing it. It was at the tanker that I had one serious duty--to
pull the circuit breaker in a malfunction. Fortunately, a previous
occupant had marked the canopy sill above the breaker in question, so
I didn't have to memorize its location. But I was ready!
After we took on 1500 lb of fuel, I flew over to the supersonic
corridor and took the jet to 1.25 Mach (630 KIAS, 780 KTAS) at 18,000
ft MSL. Mike then took it and did a maximum deceleration, with
speedbrake and throttle chop from full burner to idle. It felt like
the jet just _stopped_ in mid-air. The deceleration was about 0.5 g
longitudinally. This was very impressive, proving to me how well drag
works.
At this point we RTBed. We did a tower flyby at 350 KIAS, 150 ft AGL.
This was quite impressive. The lakebed doesn't have a lot of texture
and judging altitude was very difficult for me. Mike turned on the
radar altimeter at about 300 ft AGL, which was reassuring. Although it
was difficult to judge our altitude, it was very easy to see that we
were moving across the ground really quickly. We pitched out and
entered the pattern. I really liked the break. We had to extend our
downwind leg because the tanker did a long straight in. On final Mike
decided to wave off because of the wake turbulence of the KC-135. We
went back around the pattern and did a full stop landing. We turned
off the runway at the center taxiway and dropped our drag chute.
The maximum g level of this flight was 5.4 g and the minimum was 0.5 g.
The g suit worked well and I didn't notice any reduction of my
peripheral vision with g. I had noticed this in the F-104 when pulling
about 4.5 g without a g suit or the straining maneuver. I found the
action of the g suit surprising the first few times it activated, but
quickly adapted to it. I had more trouble with the helmet and mask.
The helmet was one of the older style and was uncomfortable and
noticeably heavier than the new lightweight one that I got from ADFRF
Life Support for my NT-33 flight. On consideration, I should have
taken the ADFRF lightweight helmet with me. Whenever we pulled more
than about 3 g the mask slid down over my nose and the helmet came down
over my eyebrows. I finally discovered that I could prop my elbows on
the canopy rails and support the helmet. This increased the visibility
and reduced the strain on my neck. I suspect that this helmet was not
very safe, but I didn't have to test it.
At one g, where the helmet wasn't a factor, I thought the visibility in
the F-4 was pretty good. Looking for traffic, for example, I had no
trouble looking back to 5 o'clock. Down and back was somewhat obscured
by the wing, of course. The forward visibility in the pit is pretty
bad, though. To look between 11 and 1 o'clock I had to duck down and
lean to look over the pilot's shoulder. Of course, I had just flown in
the front seat of the NT-33, which has excellent visibility, so I
noticed the lack. The back seat of the F-104 had visibility very
similiar to the F-4, except that the wing is smaller.
Preparation for this flight included one-timer egress training, which
was also very interesting. There's a half-hour lecture and then we
went out, put on the torso harness and helmet, and got lifted up to
dangle in the harness and practice the normal, tree, and powerline
descents, followed by one landing. Then we went back in and practiced
with an actual (no pyros though) seat. The F-4 seat won't fire unless
the canopy has jettisoned, so the ways to do this if the auto sequence
fails were emphasized. There are several things to try--the normal
canopy control, the emergency jettison, the manual jettison, and the
last, desparate hacking at the canopy with the canopy cutter tool.
Being outfitted for this flight was very interesting. I've never worn
a g suit before. Nor have I used a torso harness. It felt quite odd
when I was all suited up and we stepped to the jet. I was really
bundled up--long-sleeved turtleneck, flight suit, winter-weight flight
jacket, torso harness, and g suit. I was a little worried when I stood
at the foot of the ladder, looking up at the cockpit. The backseat
canopy sill is 11 ft AGL. (For the F-104 one wears a heavy parachute.
The chute is integral to the seat in the F-4 and NT-33.) But I climbed
right up the ladder, stepped onto the top of the inlet, and thence into
the cockpit. The rear cockpit of the F-4 is somewhat cramped and
uncomfortable and I had a little trouble getting strapped in. The
first thing I did was fasten the garters over my camera and barf bags,
which were in the leg pockets of the g suit. I then completed
strapping in, only to discover that I couldn't reach the leg pockets.
Mike had to retrieve the stuff in them for me. I put my camera in my
right jacket pocket, except when I was actually taking a photo, so that
it didn't get loose and FOD the cockpit. I had no further problems
with it.
It was much quieter inside the airplane than I expected. I remember
the F-104 as being much noisier. My feet and lower legs got very cold
and I don't see how Mike can stand this on a seven or eight hour cruise
missile chase mission. Near the end of the flight I was very tired (I
didn't get much sleep the night before, for some reason) and a little
uncomfortable and my gyros started tumbling. I think that the tower
flyby contributed to this since I was looking sideways. Had this not
happened we would have done some touch-and-go's. Fortunately my gyros
didn't tumble completely and my honor and dignity remained intact.
Mary Shafer
More comments:
Mike later told me that when he went through egress training they told
him that only one person (who both of us know) has ever gotten out of
the F-4 by using the canopy cutter when the canopy wouldn't jettison.
It was during the (Israeli) 67 war. He took a hit and they had to
abandon the aircraft. His WSO got out OK, but the pilot's canopy
didn't jettison, so he chopped his way out and jumped over the side.
He was taken prisoner and spent three years as a POW, but was
eventually exchanged and went on to become an ace (against MIGs). I
also saw Mike Love's death, when his F-4 caught fire on takeoff here at
Edwards. He brought it around, over Dryden, and initiated the ejection
sequence. Again the backseater got out, but the pilot didn't. He
brought it on around and went into the lakebed, quite close. I saw the
entire ejection sequence and realized that only the pitter had gotten
out. It was really quite horrifying, seeing the burning jet with a
huge flame two or three times its length and then seeing only the one
ejection, followed by the crash and explosion. The AIB reported that
the pilot's canopy jettison sensing switch had been disabled during
maintainence.
I noticed some acronyms--
ADFRF Ames-Dryden Flight Research Facility
AFFTC Air Force Flight Test Center
AIB accident investigation board
AGL above ground level
FOD foreign object damage
KIAS knots indicated airspeed
KTAS knots true airspeed
NORDO no radio
MSL mean sea level
RTB return to base
WSO weapons systems officer
I also notice that this is, to some extent, written in jargon. Rather
than translate each piece, since the meaning may be obvious to you from
context, I'll let you ask specific questions. I have to admit that we
do really talk like this, since the purpose of jargon is to make life
easier for the initiated.
Would you please e-mail me a copy of whatever you post? News has been
a little sporadic here as the server is being upgraded. Feel free to
excerpt or comment as you wish, since this is kind of long. If you do
edit it radically, though, I'd like to see it before you post it, just
to be sure that the meaning isn't inadvertantly changed.
There's nothing sensitive here, incidentally. After the carry-on about
SR-71 "secrets" I thought I'd better say that explicitly.
Yours,
Mary
M F Shafer
NASA Ames-Dryden Flight Research Facility
shafer@elxsi.dfrf.nasa.gov