From: Mary Shafer <shafer@reseng2.dfrc.nasa.gov>
Newsgroups: rec.aviation.military.naval,rec.aviation.military
Subject: Wheel-up landing programs (was: Airborne engagements flight tests)
Date: 18 Sep 1998 11:48:46 -0700

Notice the cross-posting, which is not usually proper.  However, in
this case, I thought it would be all right.  Followups are set back to
rec.aviation.military.naval, though.

"The Jam" <the_jam@usa.net> writes:

> Mary Shafer <shafer@reseng2.dfrc.nasa.gov> escribió en artículo
> > I saw that video.  I was peeking between my fingers, which were
> > covering my eyes.  The only landings I've seen that looked worse were
> > the AFFTC experiment where they landed an F-4 gear-up by catching a
> > cable with the hook and slamming the plane down on to inflated mats.

> Wow!! Did the plane survived the 'test'? I'd have liked to see the aircraft
> after that...
> And what about the crew? Was it manned? If it was, in what shape were they
> when they got out?

This was one of those Saturday-morning historical presentations at an
SETP Symposium in 1975, the first SETP Symposium I ever attended.  I
mixed up two presentations, one on the AFFTC HAVR BOUNCE project
(presented several years later), which used an F-4 to test the steel
mat repairs for runways and taxiways, and the nther on the various
wheels-up landing developement programs.  This latter is the one I
thought used the F-4, which was wrong.  The paper is "Wheels Up
Landing Development Program" by the Honorable John M. Moore (AF),
Mayor, Cocoa Beach, Florida and I have summarized and quoted all the
following from it.

The driver for the wheel-up programs was the weight saving possible if
aircraft didn't have to carry landing gear around unused except for
takeoff and landing.  An airplane without landing gear would take off
using a little trolley that would stay on the ground, or drop off just
above it, with a rocket for extra thrust, if needed, and would land
using some sort of catching system with a wire and a resilient
energy-absorbing "runway".

There were three different services trying to make wheels-up landing
work, the USAF at Edwards, the USN at Patuxent River, and the RAF or
FAA at Farnborough.  The USAF used an F-84G and a "runway" made by GE
that was a lot like the British Flexdeck.

On the first USAF wheels-up landing "the hook struck the approach
ramp, bounced over the arresting wire and returned to deck contact as
the airplane flew level over the [GE-made inflated flexible] deck.
The hook then encountered a puddle of water sprayed on the deck for
lubrication, the impact of which closed the micro-switch [installed to
retract the flaps, preventing damage of the flaps and the deck] on the
hook, retracting the flaps on the test vehicle.  The F-84[G] the
settled onto the deck, skidded the remaining length of the deck,
dropped into the desert and ground to a halt in a large cloud of dust.
This incident resulteed in excessive damage to both the test vehicle
and the test pilot, putting both out of the program.

"A second test vehicle was prepared and a second pilot located who was
willing to pursue this interesting program.  Following a brief
training program, the Air Force scheduled its second landing.

"In this landing, the arresting hook successfully engaged the cable
causing the airplane to pitch violently into the deck on its nose for
a series of 3 or 4 bounces before coming to a halt.  Motion pictures
showed that at the first impact, the pilot, who was strapped in
snuggly [sic], disappeared completely in the cockpit on initial
impact.  This left a clear impression of the pilot's central and
lateral incisors on the top of the control stick, and also caused a
severe injury to the pilot's neck.  This terminated the Air Force
wheels up landing program.

....

"Not to much can be reported on the zero launch program, primarly
because there was some reluctance on the part of the Defense
Department to release this information except to the enemy.

"In summary, however, the F-100 was perched on a launching pad, angled
approximately 30 degrees skyward, and a solid state booster was
strapped to the aft ventral side of the airplane immediately below the
horizontal stabilizer.  After the pilot had been forced into the
cockpit and securely strapped in, the F-100 jet engine was started in
preparation for lift off.  Take off was made with wheels down which
indicated some spprehension about the success of the mission.  Following
afterburner ignition the solid booster rocket was ignited which
initiated lift off.

"The first zero launch was successful in all respects with the spent
booster being jettisoned at approzimately 200 kts.  A normal landing
was made at Edwards Air Force Base following this marvelous
achievement.

"Tne second launching was also a gratifying success with one minor
problem occurring, i.e. failure of the booster rocket to jettison,
which resulted in an aircraft c.g. somehwere in the vicinity of the
horizontal stabilizers.  Without any additional bonus, Mr. {Al]
Blackburn demonstrated not only the zero launch capability of the
F-100, but its ejection system as well.  This terminated the zero
launch program."

The USN Flexdeck, which is the one the movie came from, had an
approach deck with a 5-deg. slope created by the size of the inflated
bolsters and then the flat deck was made of another 18 bolsters, each
30 in. in diameter.  The bolsters were covered with carpet and greased
with silicone before each landing.  The airplane was an F9F-7 that had
been extensively modified.  There's way too much to summarize here,
but this program was sort of a success, in that they didn't damage any
airplanes and they didn't hurt anyone too badly.

Following the USAF injury, the USN developed some protective equipment
for their program.  The pilot's helmet had a pin which locked into a
full-length backbrace so that he wouldn't injure his neck, and "[t]he
initial procedure was to lock the head into position on the down
win[d] leg, then report turning base, wheels-up, head up and locked.

"An unexpected phenomenon was encountered in this practice, however,
which resulted in a modified approach technique in which the straight
away in the final approach was lengthened so the pilot could lock his
head up while straight and level rather than having to make a 180-deg
turn with his head locked rigidly up.  The problem was that the
pilot's perception of turning with his head fixed to the vertical axis
of the airplane was disorienting-it was as if the airplane were fixed
in space, with the horizon rotating around the airplane.
Uncomfortable, at best, disorienting, at worst.

"Another anomaly associated with the protective harness resulted from
its weight.  It was calculated that with the harness installed and the
life jacket inflated (in the event of a water landing), the buoyancy
was slightly negative.  A simple procedure was developed to resolve
this, to wit--in the event of a ditching and following the pilot's
safe egress from the airplane he had but to remove the life jacket,
remove the parachute, remove the protective harness, reinstall the
life jacket and inflate it.  It was expected this could be
accomplished with the pilot standing on the bottom of the Chesapeake
Bay."

The British system, which was up and working at Farnborough using a
Vampire, was used by the Navy test pilots as an introduction to the
flexdeck.

"The procedure at Farnborough was straightforward.  One dry run was
made with hook up in the up position over the flexdeck at an approach
speed of about 90 knots.  The hook was then lowered, and in a straight
away of about 3,000 feet a 10-deg glide slope was established aimed at
the center of the flexdeck.  Engagement was evdcent by the pitching
down and rapid deceleration of the airplane followed by several
relatively mild impacts and about a dozen bounces until the airplane
halted, all in some 100 feet.  It was a little like being dribbled by
Wilt Chamberlain.

"The engine was shut down and a cable hooked to the nose of the
Vampire, allowing it to be w[i]nched off the deck onto a flatbed
truck, the pilot remaining in the cockpit.  The airplane was
transported to some facility on the outskirts of the airport where a
crane was off-loading sewer pipe from railroad cars.  The crane
operator was gracious enough to pause the sewer operation, and lift
the Vampire from the flatbed truck.  While suspended from the crane,
the pilot lowered the wheels and the airplane was then lowered to the
ground.  The Vampire engine was started there, and the airplane
taxied along the left hand side of the road (of course) back to the
airport for a second take off and landing.  A total of six arrested
landings were accomplished in this manner, followed by a touch and go
(bounce and go) landing to allow the pilot to familiarize himself with
this phenomenon."

As to the results of the program, they made 23 landings, but the 20th,
in which they found "runway" rubber skid marks on the _tops_ of the
wings, was a pretty clear indication that the technique wasn't
practical.  "If the first Air Force landing [program] did not disprove
the flexdeck concept, this landing certainly did."

--
Mary Shafer               NASA Dryden Flight Research Center, Edwards, CA
SR-71 Flying Qualities Lead Engineer     Of course I don't speak for NASA
shafer@reseng.dfrc.nasa.gov                               DoD #362 KotFR
URL http://www.dfrc.nasa.gov/People/Shafer/mary.html
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