Can F-15s making 9G turns with payload?

The F4 wingtips cracked from vibration, not G. However, G set up the
vibration. Flying close when when lead was doing acro one could see
the wing tip vibrating as the tip vortices did their 'Karmann trail"
thing. The 110v 'thin filament' tip lights used to fail in a jiffy
until they rewired then for 28vDC 'heavy filament' bulbs.
We had an F4 at low altitude peg the G meter both ways when the tip of
the 600gal centerline came off as the pilot (Stormy FAC) dodged a SAM
coming right in from 12:00. Later a second F4 had the tip shot off his
centerline tank and the Gs piled on the same way. Turns out the blunt
nosed tank sets up severely disturbed airflow over the horizontal
stabilizers.
Both aircraft checked out okay except lots of 'bubble gum' was needed
to reseal the bottom of the internal wing tanks.
Walt BJ

"Walt BJ" wrote in message
m...
The F4 wingtips cracked from vibration, not G. However, G set up the
vibration. Flying close when when lead was doing acro one could see
the wing tip vibrating as the tip vortices did their 'Karmann trail"
thing.

More apropriatly called gain in s-plane analysis, but true.

On 19 Sep 2003 10:29:42 -0700, (Walt BJ) wrote:

The F4 wingtips cracked from vibration, not G. However, G set up the
vibration. Flying close when when lead was doing acro one could see
the wing tip vibrating as the tip vortices did their 'Karmann trail"
thing. The 110v 'thin filament' tip lights used to fail in a jiffy
until they rewired then for 28vDC 'heavy filament' bulbs.
We had an F4 at low altitude peg the G meter both ways when the tip of
the 600gal centerline came off as the pilot (Stormy FAC) dodged a SAM
coming right in from 12:00. Later a second F4 had the tip shot off his
centerline tank and the Gs piled on the same way. Turns out the blunt
nosed tank sets up severely disturbed airflow over the horizontal
stabilizers.
Both aircraft checked out okay except lots of 'bubble gum' was needed
to reseal the bottom of the internal wing tanks.
Walt BJ

Thanks Walt for explaining that. I knew they were cracked, but not the
exact why. I never got over seeing those massive plates on the outer
wing panels. Just seemed like more madness of the Vietnam war...

On Sat, 20 Sep 2003 05:08:08 GMT, Buzzer wrote:

On 19 Sep 2003 10:29:42 -0700, (Walt BJ) wrote:

The F4 wingtips cracked from vibration, not G. However, G set up the
vibration. Flying close when when lead was doing acro one could see
the wing tip vibrating as the tip vortices did their 'Karmann trail"
thing.
Walt BJ

Thanks Walt for explaining that. I knew they were cracked, but not the
exact why. I never got over seeing those massive plates on the outer
wing panels. Just seemed like more madness of the Vietnam war...


The corrective reinforcing plates, while a bit ugly weren't all that
massive--probably about 4x8 inches and maybe 1/4 inch thick. The went
in place abutting the hinges at the wing fold on both sides; main wing
and tip section. The real "ugliness" was that the paint had to be
scrapped away from the hinge and reinforcement to allow visual
inspection for cracks during preflight.

Not at all related to the "madness"--simply a fact of life that metal
can only be flexed so many times before it fatigues. We had the
reinforced wings at Torrejon while I was flogging F-4Cs from '73 to
'77. Hardly noticed them after a while.

On Sat, 20 Sep 2003 15:14:04 GMT, Ed Rasimus
wrote:

Thanks Walt for explaining that. I knew they were cracked, but not the
exact why. I never got over seeing those massive plates on the outer
wing panels. Just seemed like more madness of the Vietnam war...


The corrective reinforcing plates, while a bit ugly weren't all that
massive--probably about 4x8 inches and maybe 1/4 inch thick.

I go for 12x8 and 3/8ths, but anyway they were massive to me. I never
saw anything that big on a B-52, and it seemed completely out of place
on a little F-4. (I was out of B-52s from 1966 to 1976 so the D model
and such might have grown patches like that while I was away.)

The went
in place abutting the hinges at the wing fold on both sides; main wing
and tip section. The real "ugliness" was that the paint had to be
scrapped away from the hinge and reinforcement to allow visual
inspection for cracks during preflight.

Not at all related to the "madness"--simply a fact of life that metal
can only be flexed so many times before it fatigues. We had the
reinforced wings at Torrejon while I was flogging F-4Cs from '73 to
'77. Hardly noticed them after a while.

A fact of life that the U.S. government can't supply the people that
defend it with something more than a patched up worn out airframe?

On Sat, 20 Sep 2003 20:06:35 GMT, Buzzer wrote:

On Sat, 20 Sep 2003 15:14:04 GMT, Ed Rasimus
wrote:

Thanks Walt for explaining that. I knew they were cracked, but not the
exact why. I never got over seeing those massive plates on the outer
wing panels. Just seemed like more madness of the Vietnam war...

--snip--

Not at all related to the "madness"--simply a fact of life that metal
can only be flexed so many times before it fatigues. We had the
reinforced wings at Torrejon while I was flogging F-4Cs from '73 to
'77. Hardly noticed them after a while.

A fact of life that the U.S. government can't supply the people that
defend it with something more than a patched up worn out airframe?


I checked out in the F-4C at Luke in April/May of '72, then went to
E-models at Korat. The C at Luke was more than adequate to do the job
although I would have liked consistent switchology with the airplane I
was going to fly combat in. Still, I managed to cope without too much
trouble.

After leaving Korat, I flew C's at Torrejon for four years, from '73
through '77. The C was certainly not "worn out" by a long shot and
because of the relative simplicity of the weapons system (no WRCS,
TISEO, TREE, LES, etc.) it had a higher in-commission rate than D's in
England or E's in Germany at that time. We had responsibility in USAFE
for the NATO Southern Region, and were more than 1/3rd deployed
continually.

We did nuke alert in Aviano and Incirlik, air defense in Spain and on
other deployments, ground attack wherever necessary and led the force
in development of anti-ship tactics.

The C with it's wing fold hinge patches was a long way from "worn out"
and the patches weren't atypical regarding fixes for a lot of various
types and models of aircraft.

When tactical aircraft cost multiple millions apiece and when the
taxpayers deserve to get the maximum bang for their bucks and when the
Congress is reluctant to approve lots of new spending, it isn't really
a bad decision.

Ed Rasimus wrote in message . ..
On Sat, 20 Sep 2003 20:06:35 GMT, Buzzer wrote:

On Sat, 20 Sep 2003 15:14:04 GMT, Ed Rasimus
wrote:

SNIP:
The C with it's wing fold hinge patches was a long way from "worn out"
and the patches weren't atypical regarding fixes for a lot of various
types and models of aircraft.

When tactical aircraft cost multiple millions apiece and when the
taxpayers deserve to get the maximum bang for their bucks and when the
Congress is reluctant to approve lots of new spending, it isn't really
a bad decision.
SNIP:

I agree, Ed, except the wheels that be could react a little quicker
when the birds are getting worn out. I was in the USAF when the F86Fs,
F100s, F105s, F4s and KB29s/KB50s/B47s/A26s all were 'retired' when
they started coming apart in the air. That cost us some good pilots.
The B52s and C130s got some heavy reskinning and doublers added to
prolong their lives.
I lost a good friend at Homestead in about 76 when the outer wing came
off during a max performance reversal - a 135* slice at .9M and and
7G- they were nose down and partially inverted and never got out of it
as the bird went into Marco Bay.
When I was working with the DC Guard out of the 31st TFW at Homestead
they were towing a 105 out of the hangar after an engine change. It
was going to be prepped for the required test hop - and a main wing
spar broke during the tow! That was it for their 105s - the previous
summer camp they lost a plane and a pilot when the spar broke during
the pitch-out for landing. Take any machine too many times to the well
and she will, some time, break on you. That, of course, goes for cars
too . . .
Walt BJ

Maybe an ECM pod did fall off a Sparrow well but that does not mean it
was installed correctly to begin with. Sparrow missiles themselevs
weigh a hell of a lot more than any of the pods that fit in the well
did. Now a good-sized country boy with a socket wrench could easily
way over-torque the bolts "Ain't no way this sucker is coming off" and
so overstress the attach bolts that not a heck of lot more stress
would be needed to snap one and fail the rest as a result. Not that
I'm saying one ever did come off. FWIW I had two of my Ds come back
with the G meters pegged both directions and nothing fell of of them.
Walt BJ