Showing posts with label EW. Show all posts
Showing posts with label EW. Show all posts

Thursday, March 13, 2014

US Navy F-4 EW development - Revisited

Ok, let’s try this again.  After much research and a heap of help from Mike France and Craig Kaston, I think I can present a better picture of the sequence of EW fits to the Navy Aircraft.   I will be presenting these in several parts, so keep coming back to see what has been posted. If you are new to this subject or these posts, I suggest you start by reading the first section so you get some background.

Just click on the links to read more about each system.


BACKGROUND INFORMATION
  • Historical Background

1965 / 1966
Equipment installed without Airframe Change (AFC):
F-4B
AFC-331 Pt. 1 (ECP-F-4-703 &703S1) installs:
F-4B, F-4J*
The KY-28 was installed on all aircraft, ships, and fixed bases in the Vietnam theater of operations starting in 1965. It synced with the KY-38 man pack used by ground forces and KY-8 vehicular unit. These units provided secure encrypted voice communications.
* F-4Js would come off the assembly line with this equipment installed.

1966 / 1967
Equipment installed without Airframe Change (AFC):
F-4B
Installed on all F-4B aircraft for VF-92 and VF-96 on CVAN-65 USS Enterprise during its 1966-1967 Vietnam cruise. These were the only aircraft with this equipment.
F-4B
Installed on 4-5 aircraft for VF-151 and VF-161 on CVA-64 USS Constellation, 4-5 aircraft for VF-14 and VF-32 on CVA-42 USS Franklin D Roosevelt, and 4-5 aircraft for VF-96 on CVAN-65 USS Enterprise during their 1966-1967 Vietnam cruises. This equipment was removed after their cruise.
AFC-296 (ECP-F-4-707R1) installs:
F-4B
Sent as kits and installed on-board during the 1966-1967 Vietnam Cruises of CVA-64 USS Constellation, CVA-42 USS Franklin D Roosevelt, and CVAN-65 USS Enterprise. Future deployments had the APR-27 installed prior to departure.

1967 / 1968
This is a time when the changes made to the EW equipment gets sort of messy. There were a lot of new EW developments that were happening in quick succession. With these changes happening so quickly it isn't always easy to tell how an aircraft was configured by merely looking at fairings. This is because we often see that a change was made and the old fairings weren’t removed, just left empty (or full but disconnected) or that old fairings were used with new equipment installed. 
Equipment installed without Airframe Change (AFC):
F-4B

(This will be referred to as "AN/APR-25 Mod 1" for our purposes - click here for more information.)

This was a pre-Shoehorn fit as seen only in aircraft of VF-142 and VF-143 on CVA-64 USS Constellation during its 1967 Vietnam cruise.
PROJECT SHOEHORN
Project Shoehorn was a program providing a complete suite of EW equipment to the F-4Bs. It was considered "state of the art" at the time, and several doors had to be added/enlarged to provide room to "shoehorn" in all the needed equipment.

AFC-333 (ECP-F-4-707R1S1, S2) installs:
  • Melpar Inc. AN/APR-30 S/C/X-band Radar Homing & Warning System
 F-4B
F-4B
F-4B
AFC-334 (ECP-F-4-761S1) installs:
F-4B
  • Magnavox AN/ALQ-91 IFF Countermeasures System
 F-4B
F-4B
First seen on CVA-59 USS Forrestal with VF-11 and VF-74 on its tragic 1967 Vietnam cruise. It should be noted that the Forrestal's squadrons showed a mix and match of aircraft on this cruise. Some were fully configured with the new shoehorn fit while others were not. It has been suggested that delays in the equipment becoming fully operational meant that the Forrestal had to sail before all her F-4Bs were fully modified to the "Shoehorn Mod 1" spec. I would imagine that the unmodified aircraft would be paired with a Shoehorn aircraft to offer some type of protection.

The disastrous fire on ship soon after the start of combat operations ended any mid cruise updates and so her surviving F-4B aircraft were not finally brought up to the full spec until her return to the USA in September 1967 with all being updated by early 1968. These surviving aircraft would appear to be the same as those modified under AFC-339 and AFC-375 in 1967 having the original APR-30 fairings but being equipped with APR-25 under the skin.

CVA-43 USS Coral Sea with VF-151 and VF-161 during her 1967-1968 Vietnam cruise ws the only carrier to bring a full compliment of  "Shoehorn Mod 1" equipped F-Bs into the Vietnam conflict. The USS Coral Sea along with the USS Forrestal were the only carriers to deploy the "Shoehorn Mod 1" equipped F-4Bs into Vietnam.

AFC-339 (ECP-F-4-761) and AFC-375 Pt.1 (ECP-F-4-830) installs:
F-4B
  • Magnavox AN/ALQ-91 IFF Countermeasures System
 F-4B
AFC-375 Pt.1 (ECP-F-4-830) and AFC-375 Pt.2 (ECP-F-4-707R2) installs:
  • Applied Technology Inc. AN/APR-25 S/C/X-band Radar Homing & Warning System
 F-4B
F-4B
F-B
It would seem that the Navy was not happy with APR-30 and decided to replace it with the proven APR-25 RHAW system and did so with many aircraft already on the mod line being prepped for APR-30 Shoehorn Mod 1.

Appears on F-4Bs of VF-21 and VF-154 on the CVA-61 USS Ranger, VF-11 and VF-213 on the CVA-63 USS Kitty Hawk, and VF-92 and VF-96 on CVAN-65 USS Enterprise on their 1967-1968 Vietnam cruises.

1968 / 1969






AFC-339 (ECP-F-4-761) and AFC-375 Pt.1 (ECP-F-4-830) continues to install:
F-4B
  • Magnavox AN/ALQ-91 IFF Countermeasures System
 F-4B
AFC-375 Pt.1 (ECP-F-4-830) and AFC-375 Pt.2 (ECP-F-4-707R2) continues to install:
  • Applied Technology Inc. AN/APR-25 S/C/X-band Radar Homing & Warning System
 F-4B
F-4B
F-B


The first aircraft to be modified to "Shoehorn Mod 3" specs in 1968 were those on the USS Constellation with VF-142 and VF-143. They differed from what became the standard 1968 fit in that while they did indeed have a single fairing fin cap already in place from their 1967 cruise they also were fitted with the original APR-30 hook shaped chin pod fairing. It is thought this was nothing more than using up the last of the available stocks of these fittings and indeed a small number of the first Marine aircraft to go into the Shoehorn project acquired the same fit.

New aircraft coming into VF-151 and VF-161 on the Coral Sea were the first to get the new and correct shaped antenna fairings associated with AFC-339 and AFC-375. It should be noted that the aircraft assigned in 1967 that were to stay with the Coral Sea's squadrons retained their original APR-30 fairings but had the revised fairings fitted when they returned Stateside at the end of the 1967 / 1968 Vietnam cruise. 

1968 saw the introduction of the F-4J to Vietnam combat operations deploying with VF-33 and VF-102 on CVA-66 USS America. The aircraft assigned to these squadrons were the first Navy F-4Js to get the shoehorn mods on the production line and the first of them was BuNo. 155529.
AFC-352 (ECP-F-4-687S3) installs:
  • Hazeltine AN/APX-76 Air-to-Air IFF System
 F-4B
AFC-388 (ECP-F-4- 840S1, S2) installs:
  • Applied Technology Inc. AN/APR-25 S/C/X-band Radar Homing & Warning System
 F-4J
F-4J
F-4J
  • Magnavox AN/ALQ-91 IFF Countermeasures System
 F-4J
  • Hazeltine AN/APX-76 Air-to-Air IFF System
 F-4J


The USS America was followed in to combat operations by (Shoehorn Mod 3) modified F-4B aircraft of VF-151 and VF-161 on CVA-43 USS Coral Sea,
VF-21 and VF-154 on CVA-61 USS Ranger with (Shoehorn Mod 4) F-4J aircraft,
VF-11 and VF-213 on CVA-63 USS Kitty Hawk with(Shoehorn Mod 3)  F-4Bs and VF-92 and VF-96 on CVAN-65 USS Enterprise with (Shoehorn Mod 3) F-4Bs.

F-4B aircraft from this 1968 / 1969 deployment period world wide would show a mix of aircraft with the original AN/APR-30 fittings of Shoehorn 1&2 and the later AN/APR-25 fittings of Shoehorn 3. But it is worth noting all aircraft would have the same AN/APR-25 RHAW system under their different skins.

It should be noted that USMC aircraft in the Pacific area finally got their own aircraft straight from the new mod lines set up in Japan and in the Philippines during this 1968 /1969 time frame. Previously any shoehorn aircraft seen with the Marines would have been ex US Navy aircraft swapped out when the Navy deployments were done. There would always be a lot of aircraft switching between Navy and Marine squadrons in this period.

During this period Atlantic fleet carriers would also start to get AN/APR-25 Shoehorn equipped F-4s (CVA-59 USS Forrestal being the only Atlantic carrier to have AN/APR-25 equipped aircraft prior to this time).

1970
APC-524 (ECP-F-4-1023R2S1, S2) installs:
  • Applied Technology Div. (ITEK) AN/ALR-45 Countermeasures Receiving Set
 F-4B, F-4J
  • Raytheon AN/ALR-50 Radar Receiving Set
 F-4B, F-4J

1975
AFC-541 (ECP-F-4-1035S1) installs:
F-4J*, F-4N**
*The first F-4Js did not have this system installed during assembly, but looking at my resources I begin to see a few with the modification appearing by late 1972. But there are also many pictures without the modification in this time frame so the conversion is by no means complete.  Pictures from 1975-76 show that most aircraft had been converted by this time.

** The first F-4Ns did not have this system installed initially during conversion, but were retrofitted by 1975. The first carrier deployment of F-4Ns was on CVA- USS Midway out of Yokosuka, Japan from September to October 1973. These aircraft did not have the shoulder wave guide antennas of AN/ALQ-126 fit yet.
Revision History:
  • 29 MAR 2014 - Added pages for Shoehorn Mod 4
  • 24 MAR 2014 - Added pages for AN/APR-25, AN/ALQ-51/100 & AN/ALQ-126
  • 19 MAR 2014 - Added pages for Shoehorn Mod 1, 2, & 3
  • 13 MAR 2014 - Original Post
Sources:
  • Michael France and his unending patience and tremendous work on F-4 Phantom II changes
  • Craig Kaston and his patience and help with the "Navy Way" of doing things

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Sunday, October 27, 2013

USAF F-4 Wild Weasel Aircraft before the F-4G



As the air war in Vietnam heated up, and the Soviet Union started supplying the North Vietnamese armed forces with better air defenses, the US Air Force realized the need for what became known as Wild Weasel aircraft to help suppress the SAMs.  Their first attempt was the F-100F Wild Weasel I aircraft.  While the F-100F was successful in suppressing SAM activity, it had one glaring weakness - speed.  The F-105s that were carrying out the bombing campaign found themselves flying very slow so they didn't out-distance the F-100s that were providing them protection.

A newer airframe was needed, one that could keep pace with the fighter-bomber formations without affecting their performance.  The two airframes that were available at the time were the F-105 Thunderchief and the F-4 Phantom II.  So the US Air Force initiated parallel programs fitting the Wild Weasel electronic suites into both aircraft.  This decision was based on the fact that there were a finite number of F-105s available as production had been closed on that aircraft, but the F-4 was still in production and could make up for combat loses with new aircraft.  This decision was to prove to be a very wise one.

(E)F-4C Wild Weasel IV

The first flight of a Weasel EF-105F took place on 15 January 1966, with the first flight of a Weasel F-4C expected to take place six months later in July of the same year.  But the F-4C conversion was very protracted and was beset by one problem after another.  The first problem was simply one of space.  While the F-105 and F-4 were roughly the same size, the F-105 was a single-engine aircraft where the F-4 with its two engines needed more real estate for fuel lines, control lines, and electronics just to operate. In short, the Phantom was a jam-packed aircraft and simply could not handle the added electronics and wiring required to properly install Wild Weasel equipment without some major revisions.

The (E)F-4C Wild Weasel went through several versions during development.  The first - Wild Weasel IV-A was a pod mounted system in the starboard rear missile well.  All of the Sparrow launch equipment and wiring were removed and replaced with the necessary electronics and wiring for the Wild Weasel mission.  Itek/ATI APR-25 and -26 RHAW  equipment was installed and a IR-133 Panoramic Receiver was put in the pod.  Sounds nice, but it didn't work, there was high interference coming from someplace and it gave either erratic displays or no display at all.  For a year the engineers beat their collective head against the wall, trying to understanding how the same system that worked well in the F-100F and EF-105F resulted in nothing but problems on the F-4.  Finally, Mr. C.K. Bullock the brain-child of the Wild Weasel I system installed in the F-100F was brought in as a consultant and he spotted the problem right away. The F-100 and F-105 both used a low-capacitance coaxial cable to carry the video information to the RHAW scopes to match the low-capacitance wiring of the of the aircraft. The F-4, on the other hand, used high-capacitance wiring on its systems so they had used high-capacitance wiring to incorporate the Wild Weasel installation.  The equipment wasn't designed for that.

With this problem solved, McDonnell began flight tests of the Wild Weasel 4, but further problems with vibration in the pod caused erratic displays, again delaying the program. Meanwhile, EF-105F Weasels were already in combat and were achieving a lot of success. It became obvious to McDonnell Engineers that somehow the system would have to be mounted internally.

McDonnell engineers began working feverishly on Project Wild Weasel IV-C, the reengineering effort to make room in the F-4C for the Wild Weasel components. Finally, in June of 1968, almost two years after the scheduled deployment of at least four (E)F-4C Weasels, the installation of the electronics in their new internal spaces was begun!  The new installation worked as advertised and the first operational (E)F-4C Wild Weasel was delivered to the 67th TFS based at Kadena AB, ROK on October of 1969. 

By this time is seemed that the Vietnam War was winding down and the EF-105Fs seemed to have things well in hand, so the (E)F-4Cs were not needed. But, the 67th TFS (E)F-4Cs would get a crack at combat. Because of the North Vietnamese Easter Offensive in 1972, President Nixon ordered a full resumption of bombing military targets in North Vietnam. Many more aircraft were committed to LINEBACKER operations than before and the sole Wild Weasel EF-105F unit in SEA could not handle the increased mission load. In October of 1972, the 67th TFS was alerted for combat duty and was sent TDY to Korat, Thailand, just in time for the LINEBACKER II maximum effort in December. The (E)F-4Cs performed admirably while flying over 460 missions


(E)F-4C Wild Weasel IV-C of the 67th TFS
The Wild Weasel (E)F-4C could be distinguished from a standard fighter only by the additional antennas on the aircraft. Around the nose at forty-live degree positions, were the four diamond-shaped homing antennas for the ER-142. Under the nose is a short blade antenna for the APR-26, and the two small stub Omni antennas directly in front of the nose gear wheel well are for the ER-142. Above the wing/fuselage juncture the raised square patch with a six-inch black circle is the ER-142 direction finding antenna. The antennas for the APR-25are found inside the chin fairing under the radome, and in a fairing on the trailing edge of the vertical fin. The rear cockpit was extensively modified with the upper right corner of the rear instrument panel being taken up with RHAW scopes and Threat Display Panels.

Thirty-six (E)F-4Cs were eventually modified to Wild Weasel IV-C specifications, twelve were assigned to the 67th TFS, Kadena AB, Okinawa, Japan; twelve to the 81st TFS, Spangdalem, West Germany; with the final twelve were assigned to the 35th TFW at George AFB, California - the new home of the Wild Weasels.

The (E)F-4C Wild Weasel was a very successful conversion once all the bugs were ironed out.  But not every weapon system is flawless.  The one glaring weakness with the (E)F-4C was the lack of the ability to use the AGM-78 Standard ARM missile.



(E)F-4C Wild Weasel IV-C of the 81st TFS

 

(E)F-4D Wild Weasel IV-B

There were two F-4Ds modified for the Wild Weasel mission under Project Wild Weasel IV-B. Both aircraft (65-657 and 65-660), were used to test the Bendix APS-107 Radar Homing and Warning (RHAW) system with an ER-142 panoramic receiver. Although the APS-107 gear was more sophisticated and accurate than the APR-25/-26 units and finally gave the (E)F-4 the ability to use the AGM-78 Standard ARM, it proved unreliable and erratic under combat conditions - at least for the Wild Weasel mission.

Several standard F-4Ds were used to test other programs relative to the Wild Weasel mission. One aircraft (65-0644) was used to test the AGM-78 Standard ARM missile, and several F-4Ds were used to perfect the AGM-65 Maverick missile.

(E)F-4D Wild Weasel V Test Platform

 At least two F-4Ds (66-7635 and 66-7647) were modified and equipped with the new McDonnell-Douglas designed APR-38 Warning and Attack System, the basis of the entire F-4G program. 

Originally, the F-4G program had originally been slated for installation in ninety F-4Ds, but the Air Force opted for the more modem F-4E.  This decision was made because the F-4E had much more internal volume available (especially once the gun was removed) and it was considered the cheaper option because the F-4E aircraft were much more up to date than the F-4Ds which would have to be brought up to the current state of the art. This was apparent in testing the (E)F-4D test aircraft which had to carry much of the electronics in a special canoe fairing which took the place of the port/forward missile launcher because of the lack of space.

The (E)F-4D Wild Weasel aircraft never progressed farther than a test platform for the Wild Weasel V electronics, so none entered active service in any USAF squadrons. 



(E)F-4D Wild Weasel Testbed


References:

  1. Drawings (c) by Kim Simmelink
  2. Wild Weasel - The SAM Suppression Story, by Larry Davis
Revisions:

10/27/2013 - Original Post

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Thursday, October 17, 2013

US Navy F-4B(N) Phantom II ECM Development

    NOTE: THIS POST HAS BEEN REDONE!

    Follow This Link to the New Information
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