Ed Rasimus wrote:
(Zajcevi) wrote:
Hello
I would like to ask few questions about Vietnam era F-4s. I went
trought many sources and I found some „blank“ areas.
1. First questions are related to Phantoms radar sets. In my search I
found almost nothing about ranges (depending on RCS and heigh level of
target) , operational modes, scan patterns... of AN/APQ-72, APQ-100,
APQ-109 and AN/APG-59 (AWG-10) and differences between each types.
I flew the E and D in SEA and then the C model in Europe for four
years after. All three models had a radar that could reach out for
mapping and beacon targets to 200 miles. Clearly at that range the
data presented was very general. Scans were horizontal, +/- 60 degrees
from center. C and D offered two bar scan while the E had a three bar
scan.
APQ-72 (F-4B) and APQ-100 were almost identical for A-A use, the main
difference being that the Air Force required the latter to have an
adjustable range strobe for bombing (not a very useful feature, actually,
given the way it was implemented). Typical max. contact ranges on a MiG in
Vietnam seem to be in the 20-30 n. mile range; I've got one account
claiming a contact at 33 or maybe it was 35nm, which was unusual. Combat
Tree contacts could be at much greater ranges (to be expected given that
they're triggering the MiG IFF transponder), at least 60 n. miles according
to some accounts I've read. IFF interrogators were later added to the
APQ-100 and 109 at least, APX-76 IIRR. Selectable radar ranges were 10,
25, 50, 100 or 200 nm - the APQ-120 added a 5nm range scale. Lock-ons
weren't possible with 100 or 200nm selected, for sure in the case of the
APQ-100 and probably the others as well. In addition to the wide sweep of
120 degrees, there's also a narrow 60 deg. sweep selectable; there's also a
choice of one or _THREE_ (not two; Ed's memory is playing him false here)
bar scan. There are a large number of combinations of polarization, pulse
length, manual or auto range tracking, gate/aspect, HOJ and other
selections possible, which are far too long to list (I've got a copy of the
1F-4C-34-1-1).
Walt Bjorneby, who'll hopefully chime in, has stated in the past that the
APQ-109 was longer-ranged than the APQ-120, owing to the larger antenna.
Basic A-A options were a normal B-scan search and lock-on mode, Boresight,
or Gyro Out, the latter mode disabling the antenna stabilization relative
to the ground and allowing the WSO to move the antenna relative to the
airframe, for high off-boresight lock-ons when maneuvering. This last mode
took a fair amount of coordination betwen the two crew compared to
boresight, and required a considerable amount of practice. Boresight was
originally a wholly rear cockpit selection, but the ability of the front
seater to select it and/or start the range strobe/jump over targets (auto
acquisition) was improved several times during the war, ultimately ending
up with the T.O. 556 F-4E's near-HOTAS setup.
AFA I'm aware, the main difference between the APQ-100 and 109 was in the
latter's air to ground capability, not A-A. Hopefully "Dweezil
Dwarftosser" (John Tomany) will comment, as he has experience maintaining
most of these.
APG-59 was a high PRF Pulse Doppler (alternatively pulse) set, with a
considerably higher average power in PD mode than the earlier sets. Good
for head-on detection of look down targets, at least over water, and
apparently considerably longer ranged on closing targets than the pure
pulse sets, at least when ground clutter wasn't a problem. Friedman's
"U.S. Naval Weapons" states that it was credited with detecting a 5 sq. m.
target at 60nm, which should be considerably better than the other radars
were capable of.
2. Also any infos about AAA-4 IRST are missing.
In '72 when I qualified in the airplane, the IRST was deactivated in
all aircraft.
Removed and replaced by the forward antennas (and maybe the pre-amps) for
the RWR in the Air Force a/c.
3. In the case of F-4J, were also VTAS HMS together with AIM-9H used
in combat during Linebacker? Or was AIM-9G most advanced Sidewinder
used id SEA?
J model was USN, so I can't comment. We carried AIM-9J.
Red Baron lists no AIM-9Hs fired and states that only the models through
the G/J were used. Other sources have claimed that some -9Hs were used,
but I've never seen a credible source/official evidence for this. VTAS
seems to have been one of those 'nice in theory, but a pain in practice'
fits that quickly went away. There are a few people over on r.a.m.n. that
have used it, who may be able to answer your question.
4. SUU-16/ 23 gunpods were widely used with many succeses during
Rolling Thunder. But never heard that they have been used also in
Linebacker. This seems to be interesting, becouse many MiGCAPs
(mainly) consisted from F-4Ds and they missiles were unreliable
AIM-9E, from second half of 1972 not much better AIM-9J and of course
AIM-7E-2. I know that this problem was sometimes solved with adding
gun armed F-4E to MiGCAPs instead of F-4Ds. So have been gunpods
carried in 1972 by F-4Ds during missins over North Vietnam?
Most of the F-4s in SEA flying from Thai bases were E models by '72.
There were no D models at Korat in '72 until a deployment from Korea
of the 35th TFS. Tahkli got the deployed folks from Seymour Johnson in
E models. Udorn which was primary for MiG-CAP flew both Ds and Es. The
AIM-9J was quite reliable
Well, that's being a bit optimistic. 4 kills in 31 attempts (pK .126),
with four of those attempts involving failures to launch, isn't all that
much better than the AIM-9B/E. Admittedly, probably four if not more of
the misses weren't the fault of the missile but of the inadequate
pre-combat testing, which assumed a far greater range for low angle shots,
especially at high-Q, than proved to be the case.
and the AIM-7E-2 wasn't bad if fired within
design parameters, unfortunately training for many didn't really
qualify folks in air/air completely.
Remember that the MiG-CAP in '72 was working closely with GCI and were
better prepared than they had been in the past to engage BVR or at
reasonable missile ranges.
The Combat Tree F-4Ds with the 432nd at Udorn wouldn't have wanted to carry
the gun pod, as it would limit their AIM-7E-2 carriage to two (unless they
jettisoned the gun pod), as well as decrease their fuel and up their drag.
With an F-4E along it wasn't worth it.
The SUU-16/23 pods carried air/air were a short term solution to a
short term problem during Rolling Thunder.
I wonder if Walt's guys at DaNang ever carried the gun pod on their forays
into NVN in 1972?
5. Last question is related to Rivet Haste project F-4Es. How many of
these birds were sent to SEA in fall of 1972? Have been also other
F-4Es partially upgraded to this standard (556 mod, TISEO, Combat Tree
or LES, or their combination?
I don't know a hard number, but I'm sure that some of the historical
statisticians in the group can help with the Rivet Haste number. I'd
estimate about a dozen. Upgrade to TCTO-556, the improved switchology
was very rapid and by August virtually all of the Thailand based F-4Es
were modified. TCTO-566 was the LES/TISEO structural mod and that was
limited to the Rivet Haste (Agile Eagle) birds out of Udorn. Someone
else will have to offer numbers of Tree birds. Never had the
opportunity to fly one.
Thought I had the number of the Rivet Haste birds, but can't seem to find
it. The second edition of Tony Thornborough's "The Phantom Story" will
likely have it. Michel in "Clashes" says they deployed as an already
formed squadron to Udorn and there assumed the identity of the 555th TFS,
much to the disgust of the 555th people already there who were transferred
to other squadrons. A quick perusal of my xeroxes from the first edition
of Thornborough fails to identify their previous squadron designation, but
in any case that implies that there may have been as many as 18 to 24 a/c
in the deployment, depending on assigned squadron strength at the time.
AFAIK the other TREE birds at the time were all Ds - it appears that it was
a depot fit. Initially the 432nd had 8 Combat Tree Ds which they got from
the 3rd TFW in Korea; around June 1972 they received some attrition
replacements.
Guy