Another question about USN F-4s and drop tanks.

[Mark B.]

 In Eli Raphael's  May 03 “Making a Come Back” thread in the LSP Discussions forum > Click here < there was a lively discussion that answered the question of  why the USN F-4 Phantom IIs only carried 2 AIM-7Es in the rear fuselage missile wells during the Viet Nam war.

During the discussion, it was stated that there was a shortage of center line tanks in the USN.  I was wondering if this shortage was Fleet wide or just a result of space limitations on board the aircraft carriers.  I know they are big but space on a vehicle of any sort is always limited very judiciously used.

 

And the whole discussion leads me to a question that has bugged me since the mid ‘70s, why did the USN shun the use of the outer 370 gallon wing tanks on board aircraft carriers?  Was it a space limitation issue again?  I mean it might take more room to store twice as many outboard wing tanks as center line tanks but then again the center line tank was twice as big as an outboard tank?  Or was it some other reason?

 

Just wondering,

 

Have a great day

Mark B.

Edited June 1, 2021 by Mark B.
Cleaning up link text

[Mark P]

IIRC, there was an issue with the CofG loading that necessitated that only the aft wells were loaded. That was determined by what, if anything, was loaded on the I/B pylons.

 

I am sure others can better help...

 

Mark Proulx 

[Finn]

I do believe it was what each squadron configuration was decided upon, some had c/l tanks others had the wing tanks:

 

 

also with a c/l tank you had room on the outer pylons for additional weapons:

 

 

 

Jari

[Ben Brown]

Weren’t there some wing fatigue issues associated with the wing tanks, in addition to the cg issues during a catapult launch? 
 

For the two AIM-7s in the rear bays only, I’ve read that they couldn’t launch from the front missile bays if the centerline tank was installed.

 

Ben

[Tony T]

I heard that there did exist drop tank shortages. Vietnam era Squadrons customarily painted the tips of tanks, MERs, TERs etc in their squadron colour (Navy Fighter Squadrons usually being golden yellow or red) to signify ownership of the jettisonable stuff on ship.

 

And it still was possible, via the circuit breakers, to override inhibitors — though it's tough getting past the monosyllabic comments to get anything definitive as to the wisdom or lack of it in overriding some of them.

I know the RAF had c/g issues on the F-4M/FGR.2, due to number 7 fuel cell in the back, if they didn't at least carry ballast pods in the forward missile wells. Not sure about the F-4J internal fuel arrangement and c/g - maybe it had better pitch trim characteristics with the inverted slotted stabilator (?) 

 

Fascinating stuff. Learn new things all the time. But it's a fight at times distinguishing the truth from rumour, even half a century later. 

 

Tony

[jenshb]

Did that Phantom have to go supersonic to catch the bogey?  Might also explain the absence of tanks to reduce drag once they had used up all the fuel in the tanks...

[Mark B.]

Hi Guys,

Thanks for the responses. 

I had not heard that there were wing or CG issues launching with wing tanks.  Got to wonder though about the photo above showing two planes from VF-33 and VF-102 from CVW-6 on USS America from some time between 1965 and 1967 with wing tanks.  Could this have been taken before the wing fatigue was discovered? 

 

On 6/3/2021 at 2:41 PM, Tony T said:

But it's a fight at times distinguishing the truth from rumour, even half a century later. 

 

Tony

 

Especially a half century later.

 

Be interesting to find some sort of directive or instruction on this. 

 

 

[Finn]

Here is a pic from 1972:

 

 

Jari

[Mark B.]

On 6/7/2021 at 12:45 PM, Finn said:

Here is a pic from 1972:

 

 

Jari

So this would be an F-4B or would it be one of the first refab F-4Ns?

 

If an F-4B it would seem to cast doubt on the wing structure fatigue issue.

 

If these birds were commuting to the Coral Sea from their land base prior to the carriers deployment  could the CG issue on launch still be an issue?