Ahh that old familiar tale you say - of course, in the late 1960s the F-4 Phantom II finally had a gun installed, which meant that everything was better, magical unicorns danced around the sky and the Vietnamese MiGs would fall from the sky in droves!
Okay so that didn’t quite happen….......what did?
Note - These articles are a compacted summary of a rather massive topic and will discuss the F-4 and Guns in Vietnam mostly ignoring missiles. Vietnam will be used instead of SEA. And USN includes the US Marines for simplicity.
Very different F-4s and Air Forces (USAF v USN)
Firstly, with different equipment, ideas and ways of doing things the United States pretty much had different Air Forces in the US Navy (USN) and the US Air Force (USAF), so it is important to draw a big red line between them with a quick summary:
US Navy F-4 Versions in Vietnam
F-4B (F4H-1) – Second F-4 version but first major production version of the F-4. F-4J - Improved F-4B Major Differences compared to the USAF
Air to Air Refueling with Drogue and Basket Use of AIM-9B/D/G/H versions of Sidewinder only as Short Range Missile. Never fitted Guns, not even pods (outside of a brief trial with the GAU-4) Internal ECM equipment. Different Radars (AN/APQ-72, -59 & AWG-10 Pulse Doppler) Had no flight controls in the back seat In 1972 preferred used of AIM-9G/H Sidewinder over AIM-7E-2 Sparrow Used more flexible Loose Deuce A-A formation tactics Carrier and land based (Marines)
USN F-4J refueling drogue and chute style (USN)
USAF F-4 Versions in Vietnam
F-4C (F-110A) – Based on the F-4B with USAF changes. F-4D – Improved F-4C. F-4E – This is the (only) F-4 with the internal Gun. Major Differences compared to the US Navy
Air to Air Refueling with Boom Used AIM-9B/E/J versions of Sidewinder Used AIM-4D Falcon for periods over the AIM-9 on F-4D/E External Podded ECM equipment Different Radars (AN/APQ-100, -109 & -120 ) Use of Gun Pods (SUU-16 & SUU-23) Had some flight controls in the back seat In 1972 preferred use of AIM-7E-2 Sparrow over AIM-9 / AIM-4 Insisted on sticking to the obsolete / useless fluid four (Welded Wing) A-A formation tactics right to the end.
USAF F-4 nears the boom of a KC-135 in 1967 (USAF)
Why no gun on the F-4 to start with?
On the 18th September 1947 the United States Army Air Force (USAAF) became the USAF and with the limited budget constraints after WWII, Strategic Air Command (SAC) was seen as security priority and was thus given the major funding over the Tactical Air Forces (TAF).
SAC culture dominated the USAF in the early years along with its doctrine of strategic nuclear bombing with massive manned bombers. Tactical Fighters (F-100/F-101 etc) under this emphasis on SAC now had two roles:
Defend against enemy bombers as interceptors. (Air Defence Command / ADC) Low level delivery of tactical Nukes. (Tactical Air Forces / TAF) Apparently, Korea never happened because by the late 1950s bombing a target in a fighter within 750ft was more then good enough (with a Nuclear weapon) so not only conventional Air to Air training went out the window but also conventional bombing!
One Air Force general noted about this period, General (Curtiss) LeMay had deliberately loaded the Air Staff with bomber guys, who were not well acquainted with things like air superiority or air-to-air combat, and who wanted to destroy enemy aircraft on their airfields. In 1957, LeMay actually tried to eliminate the TAF, but the possibility of the Army developing its tactical air support arm overrode this idea, and later that year LeMay reluctantly gave the TAF more funds to keep its mission from being turned over to the Army.
Who needs fighters anyway? - the B-36 Peacemaker takes its toddler son for a walk in 1948 (USAF)
Some of this thinking was perhaps driving the US Navy with their F4 program in the 1950s. The USN had a requirement to intercept Soviet bombers attacking the fleet above 50,000ft out of the range of gun armed fighters and thus from 1956 the AIM-7 Sparrow III was to be the primary weapon with a gun as secondary. By 1957 however the gun was deleted from the design because the new AIM-9 Sidewinder was to be the secondary weapon.
The USAF took on the F-4 as part of Defense Secretary Robert McNamara’s drive to get the services to use standard equipment with commonality. He was also interested in the conventional side of things and saw both the A-G potential as well as the A-A potential and thus the USAF received the F-4C (originally designated F-110A).
(Note: yes this was potentially one of the few things McNamara did that wasn’t a complete catastrophe!)
Of course, the F-4 wasn’t the only aircraft of its time without an internal gun (another reason seen given is that pilots would never have closed to gun range to take down a bomber carrying Nukes.)
Some other Interceptors of the era born with no internal Gun:
F-102 Delta Dagger F-106 Delta Dart (Some later got a gun under project Six Shooter from around 1969) Su-9/11 Fishpot Tu-128 Fiddler Su-15 Flagon MiG-25 Foxbat Some Interceptors that had the gun removed:
Lightning Fmk3 CF-104 Starfighter (Early) A gun was later incorporated MiG-17PFU Fresco MiG-19PM Farmer MiG-21PF/PFV/PFS/PFM/FL (PFV and PFM used by the VPAF in Vietnam along with the gun armed F-13 and MF)
F-102A Delta Dagger interceptors (USAF)
Getting a gun on the F-4E
McDonnell first proposed an internal gun for the F-4 in 1961 however it wasn’t until a potential limited war in Vietnam looked likely in 1963 that this was taken more seriously by the military for Ground Attack / strafing. By 1965 combat experience determined that a gun was a requirement and it was trialed in the F-4, and thus the F-4E was born with a nose job and new APQ-120 Radar:
This shows the 22 modules (Line Replaceable Units / LRUs) required for the APQ-120 radar
Adding the gun solved all the problems yes?
The original gun muzzle caused a few problems. Firstly gas ingestion into the engine inlets caused engine flameouts and secondly it made a loud whistling noise that apparently notified the enemy troops (and their Dogs presumably ) long before the F-4 got there. The muzzle had to be redesigned and the later F-4Es have a longer gun muzzle under the nose.
Also not shown in the diagram above, the gun assembly and ammo drum took up a lot of space in the nose and the dish/antenna size was reduced.
The Westinghouse APQ-120 was an early ‘Solid State’ radar (derived from the APQ-109) and being Solid State must have helped in reducing the obvious vibration issue when you have a massive Gatling gun sitting next to 1960s electronics! Despite this it still exceeded the reliability requirements and was similar in that regards to the F-4D radar that had no gun in the nose.
Ex F-4 flyer Walt BJ stated that the APQ-120 in the F-4E had about 20-25% less range over the APQ-109 in the F-4D.
Didn’t the F-4E just wipe the floor now it had a gun?
During Operation Linebacker I & II (1972/73):
The USAF F-4E had 22 claims in 25 (known) engagements including 7 gun kills The USAF F-4D had 27 claims in 30 (known) engagements with no gun kills So firstly, if you add an internal gun but still don’t train anyone to use it then despite any figures nothing really changes. Secondly the missiles and radars had improved since 1965 regarding close in capability and so the Gun was starting to look very secondary by now.
Considering the extra effort required for guns in skill, fuel, risk of collision, and making themselves more vulnerable, a missile would be the priority weapon regardless of the USAF training issues.
What about the gun pods?
Stop gap measures meant some squads using the 20mm SUU-16 and SUU-23 Gatling gun pods on the F-4C and D respectively – however despite some success these were somewhat inaccurate and the extra drag had a noticeable effect on range.
Looking happy to be here - SUU-23 Gun pod on the center line station of an F-4 (Clive Camm)
Some championed the Gun pod such as Korean war ace Col Frederik “Boots” Blesse after it became a useful strafing tool for South Vietnam sorties.
USAF Col Robin Olds was a tad less enthusiastic:
The gun pod wasn’t so much a speed penalty as an object of increased drag and fuel consumption. But that wasn’t my objection to the gun pod, I refused to carry it for 3 basic reasons;
It took the place of five or six 750 lb bombs. Only my older and more experienced fighter pilots had ever been trained in aerial gunnery, to say nothing of air-to-air fighting. There were perhaps a dozen of them in the 8th TFW. I had no intention of giving any of my young pilots the temptation to go charging off to engage MiG-17s with a gun. They would have been eaten alive. Instead they fought MiGs the way I taught them and did so with notable success. The US Navy briefly trialed the 20mm MK4 (GAU-4) Gatling gun pod but this was determined to be useless in operation with technical difficulties and also meant the preferred configuration of center line drop tank only could not be carried.
The not so successful MK4 (GAU-4) gun pod at China Lake (Dave Woolsey)
Did the Navy not want an internal or any gun?
For the primary purpose of fleet air defense, ‘missiles only’ it seems was deemed adequate. When in combat over Vietnam some Navy pilots wanted it and others didn’t. The gun pod was not persevered with and even an offer of free SUU-16/23 pods from the USAF was turned down on one occasion.
We can deduce that if you reshaped the F-4J nose like the F-4E then you also have to reduce the radar dish size and forfeit range which might not be the best idea regarding fleet defense.
Simply plonking in the APQ-120 with less range and no useful lookdown/shootdown capability was probably not going to win USN favour. Even spending the money on a modified APG-59/AWG-10 still gets you reduced range at the end of it.
The APG-59/AWG-10 in the F-4J had some good lookdown techniques (for its time) and was considered superior. However even without the gun the F-4B/J Phantom avionics suffered from heavy carrier landings:
I had a USN F4J pilot in my back seat one night gunship escort mission (can't for the life of me remember why) and he marvelled at the radar pickup. I asked him why he thought it was so good when he was flying the J model. He told me after about 4 'standard' carrier landings the radar wasn't so hot anymore. (Walt BJ)
So, what did the Pilots say about Guns, Training, and Back Seat Drivers
During the Vietnam conflict a Secret project (Red Baron) took place which compiled every A-A engagement fought. As part of that the aircrews were interviewed where available, giving quite a mixed view.
3 April 1965 F-4B USN front seat pilot (with 1000 hours)
There is a need for a close in weapon as a backup on any mission……………….Guns would also be useful as an air-ground weapon (stopping a truck convoy, for example)
10 July 1965 USAF F-4C front seat pilot
Gun not necessary; it will get people into trouble. Would like capability to fire all missiles on the F-4 with Centreline Tank on. Less minimum range for missiles instead of guns…….Because lack of ACT at time of event, did not know how to manoeuvre the F-4 as well as he could later after some experience.
6 Oct 1965 USN F-4B front seat pilot
Fighter needs guns or short range missile……………..Turning and acceleration rate of MiG-17 was impressive. The MiG leader was aggressive and a good fighter pilot.
23 April 1966 USAF F-4C front seat pilot
Improve the performance of the AAM and the gun will not be needed…………Training safety restrictions severely limited air-combat-tactics training prior to deployment to the combat area.
23 April 1966 USAF F-4C front seat pilot
The need for a F-4 gun is overstated, although it would be of value if it could be obtained without hurting current radar and other system performance. If you are in a position to fire guns, you have made some mistake. Why after a mistake would a gun solve all problems. Also having a gun would require proficiency at firing, extra training etc. Have enough problems staying proficient in current systems. If the F-4 had guns, we would have lost a lot more, since once a gun dual starts the F-4 is at a disadvantage against the MiG.
23 April 1966 USAF F-4C front seat pilot
Felt that he had very poor air-combat-tactics background. Prior background was bomber and other multi-engine. Transition to F-4 oriented toward upgrading a qualified fighter pilot rather than training a pilot with no fighter background.
25 April 1966 USAF F-4C back seat pilot
Gun is not particularly desirable, if the performance of the aircraft is degraded by an external installation. Also, one might make the mistake of getting into a turning battle if a gun was available
25 April 1966 USAF F-4C back seat pilot
Capability of the F-4 is being wasted by having a pilot in the back seat. The pilot is not adequately trained as a radar observer. Need a radar expert in the back seat. The pilot back seaters main goal is to be upgraded to the front seat rather than master the radar.
26 April 1966 USAF F-4C front pilot
It is a fallacy to say that you can bring the F-4C home and land it solely from the back seat. You’ve got to blow the gear down and then there is no antiskid system; there is no drag chute handle; there is no fuel gauges or switches; you may be limited to using internal fuel; you can’t dump fuel or jettison tanks.
A gun would be nice in an F-4C as long as it was clearly understood it was only a weapon of last resort. Soviet fighters are more capable than US aircraft inside gun range.
29 April 1966 USAF F-4C back seat pilot
It was not necessary to have a pilot in the back seat of the F-4 except during night A-G missions when a pilot may more capably advise the aircraft commander. Actually, a radar officer would be more interested in the back-seat operation than a pilot would be.
29 April 1966 USAF F-4C front seat pilot
It would be undesirable and possibly fatal for an F-4 to use a gun in fighting with a MiG because the MiG is built to fight with guns and the F-4 is not.
30 April 1966 USAF F-4C front seat pilot
Training was not really adequate for this engagement, didn’t know what the back should do in a hassle such as this.
14 June 1966 USN front seat pilot
Guns would be most useful for the ResCAP role but not particularly valuable in the air to air role.
An F-4B from VF-111 Sundowners giving it some - just because (USN)
The F-4 Phantom II Dogfighter?
As we know the F-4 was not particularly the most agile fighter in theatre and turning at a slower speed was a bit of a problem. However, US fighters had seldom been the best turners in previous conflicts such as WWII (think F-6F Hellcat V Zero) ……power and speed could make up for it and were often better attributes to have.
In 1966 the US Navy flew “Project Plan” flying the F-4B against a series of fighters to determine how good it was in an Air Superiority role. It concluded that contrary to what F-4 pilots thought the F-4 was the best air to air fighter in the world (including the F-8), if the F-4 stayed fast.
To fly the F-4 however in BFM/ACM you needed to have training and a lot of experience (like most jets of this era). One particular characteristic of the hard-winged F-4 was “Adverse Yaw” at slower speeds where the pilot had to make the turn using rudder pedals instead of the stick. If the stick was used the chances of departing were very high – somewhat fatal in combat. Now stick a pilot in the cockpit with little training and you can see that in the heat of battle adverse yaw becomes quite serious (not just A-A but avoiding SAMs etc). Of course, pilots just simply avoided going anywhere near adverse yaw if they could however that meant they could never max perform the jet if they needed to in every situation.
Adverse Yaw was all but eliminated by adding leading edge slats to the F-4E with the 556 "Rivet Haste" Mod late 1972. Too late to have any real relevance for Vietnam though.
In Part 2 we look at the very different training aspects of the USN/USAF/VPAF, the F-105 / F-8 paradox and the myth / legend of Colonel Tomb.
My massive collection of aircraft and related insignias, emblems and patches!
I forgot to mention, I didn't create all of these...didn't mean to imply I made them all...I collected them from all over...here and the net...
I could not find the source (CombatAce Links) for some of the items, (didn't remember where I got it from) so I removed them...sorry about that...