Wing tanks vs centre tank, any views?

[Mr_sukebe]

I see that the centre tank carries nearly the same amount of fuel as a pair of wing tanks.

Any thoughts about the pros and cons?

My initial “guess” is that maybe the centre has slightly lower drag and might roll faster as it’s closer to the centreline.  Haven’t done any testing yet.

Using the centre prevents carrying bombs under the fuselage, which might be preferable for delivering bombs one at a time to avoid trim issues.

Thoughts?

[Q3ark]

I think the centre tank also prevents you from firing the forward pair of sparrows, you have to dump it before you can use them. 

[Esac_mirmidon]

Also prevents you for using fore Sparrows, so more cons than pros.

[Mr_sukebe]

Thanks chaps, hadn’t realised that.  Time to rework my custom loadouts

[PhantomHans]

From what I understand:

During the Vietnam Era the USAF preferred using the pair of wing tanks.

The USN preferred using a single centerline tank, despite the risk of a bridle slap puncturing the tank during launch.  It seems this was a trim/balance/handling thing.

The centerline tank would obstruct the forward AIM-7s but you can always jettison it in order to fire them.  It would not have prevented them being loaded.

Later on the preference among most or all users switched to the centerline tank.  During the later part of the Phantoms career, the use of F-15 centerline tanks became common as they were rated for more Gs.

You'll find that the F-4G used the center tank almost exclusively to keep the wings open for missiles.

Edited May 25, 2024 by PhantomHans

[Gunfreak]

Historically in Vietnam, USAAF used 2 wing tanks for air to ground missions.

And all 3 tanks in MiG CAP

[Nealius]

Depends on how much fuel you need, what your mission set is, and potentially what service country you're portraying. Photos from Vietnam show everything from centerline to wing tanks for A2G missions. In JASDF service, EJ Kai almost exclusively flies with centerline, occasionally all three bags. RF-4EJ almost exclusively with wing tanks (due to centerline having a recon pod).

[Kalasnkova74]

17 hours ago, Mr_sukebe said:

I see that the centre tank carries nearly the same amount of fuel as a pair of wing tanks.

Any thoughts about the pros and cons?

My initial “guess” is that maybe the centre has slightly lower drag and might roll faster as it’s closer to the centreline.  Haven’t done any testing yet.

Using the centre prevents carrying bombs under the fuselage, which might be preferable for delivering bombs one at a time to avoid trim issues.

Thoughts?

It depends

USAF F-4s flew with wing, centerline or both based on circumstances and mission. On many sorties, especially MIGCAP coming from Thailand, they flew with all 3 plus full A/A loadout. Since the MIGCAP flights jettison all external tanks anyway before engaging, the centerline store interlock wasn’t a factor. 
 

To highlight the variety of setups some operators used, the Israelis ran an asymmetrical loadout in October 1973 featuring centerline bombs, 750s on one wing station, AIM-9s on the other & two wing external tanks. Much later the USAF used centerline tanks for F-4Gs operating in Kuwait , but both deployed squadrons later switched to a three bag setup to maximize fuel range when the Weasels needed to cover Iraqi airspace too. It just depends on the mission and operational need. 

[Biggus]

For me it's mostly a question of appropriateness to the scenario.  I believe our current CL tank model is the late, high performance one and wasn't really available until the mid '80s IIRC.  But once it was available, it was generally preferred from what I understand.

[Mr_sukebe]

Again, my thanks guys.  Very much appreciated 

[PhantomHans]

12 hours ago, Kalasnkova74 said:

 

To highlight the variety of setups some operators used, the Israelis ran an asymmetrical loadout in October 1973 featuring centerline bombs, 750s on one wing station, AIM-9s on the other & two wing external tanks. 

They did lots of other weird stuff but didn't they also "slant load" the inboard pylons at some point?  750s on the bottom and inboard TER mounts leaving room for one AIM-9 rail and missile each side?

[Kalasnkova74]

1 hour ago, PhantomHans said:

They did lots of other weird stuff but didn't they also "slant load" the inboard pylons at some point?  750s on the bottom and inboard TER mounts leaving room for one AIM-9 rail and missile each side?

Close. In the 80s they omitted one 750 in exchange for a single AIM-9/Python. The problem was later solved with a dedicated AIM-9 pylon attached to an adapter hardpoint using the forward Sparrow missile well.