The Drop Tank Dilemma

[MigBuster 2,861]

For virtual pilots the question of when to ditch your drop tanks is an easy one, that’s right when you feel like it! Of course but when it comes to real world use it has never been that straight forward. So how have they been used in combat over the years?

Older viewers may remember the Yankee Air Pirate team actually disabling tank jettison in some of their missions for Wings Over Vietnam to stop players dropping them ha.

Quite frankly no one gave a toss about these rather mundane items until the F-35 showed up it seems when all of a sudden they became a massive burden on older generation jets with arguments going to the point of stating they couldn’t even be jettisoned!

So now for a rather exciting history of some drop tank usage in combat.

 

A bit of background
Drop tank usage became common in WWII, and most will know about P-51s and P-38s on Escort over Germany with drop tanks which were jettisoned when the German fighters showed up. The need for this was to extend the range of the aircraft. [doh really]

P-51 flight with drop tanks (Historylink101.com)

So, couldn’t they just put more fuel internally?
You may notice that tanks used in WWII were relatively small……..piston engines didn’t need that much fuel compared to jet engines. But, by the late 1950s drop tanks had become much larger because the Jet engines were getting more powerful and thus needing much more fuel.
More Jet fuel means more weight and fuel is very heavy and takes up space, so if someone is designing a fighter with a set of performance requirements they often had to keep internal fuel to a minimum and put the fuel to meet the range requirement externally in drop tanks.
The idea being that the pilot flies to the combat zone on drop tanks but has to jettison the tanks when performance was required.

 

Into the Korean War era
Jettisoning tanks was not always as smooth as in flight sims.

May 20 1951 James Jabara was part of a 4 FIW fighter Sweep over Sinuju. As soon as MiG-15s were sighted the order came to drop tanks and Jabara punched them but only the left (Port) tank dropped. Stuck with one tank he was supposed to return to base but disregarded orders and managed to get one confirmed kill (by both sides) and damage a second despite the asymmetric control problems he must have been having.  

F-86 v MiG-15 over Korea (Troy White)

 

 

F-105 and Vietnam era
In this era dropping tanks was common but again didn’t always go without drama.

“We never did figure out why they had to drop them right on top of us, and I can assure you that a 20 foot long fuel tank in the face can ruin your entire day.” (J Broughton)

So wrote Jack Broughton in 1969 regarding his F-4 escorts, and in Vietnam, flights sometimes even dropped tanks just to go into the combat area clean. This also applied to some Thud drivers as well it appears although Broughton states he preferred to hang on to the tanks if he could for ResCAP. Basically in a ResCAP [Rescue CAP ] situation if the F-105 gets low on fuel they would leave the combat area to Air to Air Refuel, but it needed the tanks to get back to the combat area again for any useful period of time.

If they knew they wouldn’t have to refuel again during ResCAP (e.g. getting dark) dropping the empty tanks was done anyway to increase endurance [due to the reduction in Drag and weight].

F-4s had to drop their centerline tanks at least to be able to fire AIM-7s, and ideally ensure they were flying at a speed and attitude / AoA [Angle of Attack] where the tanks didn’t hit the aircraft after jettison and ruin the pilots day! In 1973 Paul Howson fired two AIM-7E-2 Sparrows and both hit the centerline tank although luckily they didn’t penetrate it. Although he thought he had jettisoned the tanks earlier the centerline tank was still attached due to a failure.    

F-105D Thuds with a KC-135A (USAF)

 

“It is hard to figure out how we can go to the Moon, yet we can’t build a fool proof system that will allow you to let go of a big blob of a tank when you want to.” (J Broughton)

Picking up SAM activity the flight of Thuds dropped the tanks, but the curse of the hung drop tank affected one of the flight. The drop tanks now being bigger was a bigger problem because that one aircraft with a hung tank now needs to use a lot more fuel to keep up with the flight, or the rest of the flight needs to fly slower through the danger area!

On one mission Jack discovered a failure on the 650 Gal tank that meant he couldn’t transfer fuel from the A-A tanker (KC-135) so opted to jettison it when empty on the way there. Again, getting rid of the tank when empty increased endurance enough for the mission by reducing overall drag and weight.

 

 

Meanwhile over Israel
Typically, Israeli pilots jettisoned the drop tanks when they were vectored towards any suspected enemy aircraft. During the Yom Kippur War this got to 50 drop tanks jettisoned per day, and they were jettisoning them even if the contact they were vectored to was false or friendly. To avoid such waste the policy was changed so they would only drop them once they had visually acquired their targets!

On the 14th April 1969, Rouven Rozen had a bit of a pilot fail when he forgot to jettison the centerline tank on his Mirage IIICJ and ended up with a MiG on his tail after some rather sub-par maneuvering. Luckily the MiG pilot wasn’t so hot and he managed to pull him into a scissors and turn things around by getting behind the MiG.

In another instance Iftach Spector was flying towards contacts they were vectored to on their radar which turned out to be Drop tanks that had been jettisoned by MiGs falling from the sky.

IDF Mirage IIICJs (dailykos.com)

 

 

The 4th Generation arrives
When the F-15/16 came along they had the same design concept as the previous generation F-4s which was fly to the target on external fuel and jettison them for combat however there was one major change. The drop tanks were manufactured to a higher quality and could be used at 9G when empty. Most of the F-4 drop tanks in Nam were ferry tanks and were not really stressed for combat as such but made good canoes. This change no doubt drove up the complexity and cost of the tanks and provided more incentive for the air force to not just jettison them for the hell of it.

Some of those drop tanks were converted into canoes by enterprising Vietnamese farmers (Aviationist.com)

 

Into the Storm

Now for some examples from more recent conflicts, typically they are jettisoned in emergency situations which includes any A-A engagement, flame out or SAM being fired at you.

Desert Storm had its fair share of A-A and A-G action, here Jerry Oney in an F-15E taking a big risk:
"Well there we were, a couple of the USAF’s finest, flying the mighty Strike Eagle at around 2000ft below a mostly scattered cloud deck in a two-mile trail at 500kts conducting a road recce for some scuds. Even then I was thinking “this isn’t the greatest idea in the history of the earth”. I was soon proved correct as we flew past this Iraqi airfield and saw the smoke trail of an SA-7, or maybe an SA-9, heading past us and towards lead. The next bit of action seemed compressed into about two seconds or less – lead broke hard into the missile in an attempt to defeat it, I watched the thing overshoot and detonate about 500ft above lead, Bill [the pilot] manoeuvred hard to avoid lead as we now had a face full of F-15E heading towards us. Damn an Eagle can turn.
I felt all our ordnance come off the airplane as Bill calmly punched the jettison button as part of our attempt to avoid hitting lead and get our weight down in anticipation of another shot coming our way."

F-15Cs with drop tanks (USAF)

 

Cesar Rodriguez flying an F-15C describes one engagement with a MiG:
"…so the western AWACs called on GUARD, Pop up contacts, 330 degrees for 13 miles. At 13 miles I had no option but to engage without any SA [Situational Awareness] , so I directed an in-plane turn to 330 degrees, jettisoned wing tanks and put my radar into the location of the target….."

 

Here is another account from Rhory Dreager and Rodriguez of a different engagement in an F-15C:
"We do not want to get into any turning merges if we did not have to, so we get our MiG-23 EID [Electronic ID] and AWACS clearances out of the way well before we could shoot. The MiGs were flying at 500ft, and we were flying a cut off intercept on them. At about 40 miles, AWACs told us that one of the MiGs had returned home, so we now had a radar picture of a three-aircraft “Vic” – one guy out in front and the other two guys flying behind and either side. Rodriguez added that RC-135 Rivet Joint also confirmed the EID on the MiG-23s. Dreager ordered a jettison of wing tanks to allow better maneuverability and greater speed with which to increase their WEZ."

 

17 Jan 1993 F-16C pilot Craig Stevenson was on a no-fly zone patrol with an F-4G over Northern Iraq when a MiG-23 started darting to the no-fly zone. As soon as AWACs had identified the MiG as hostile and called “commit” Craig jettisoned his nearly full fuel tanks but held onto his bombs.
“At .95 mach I was well above the selective jettison design limitation for the fuel tanks, and the aircraft was quick to let me know. The jettison was so violent I remember looking back at my horizontal stabilizers to make sure they hadn't been damaged by the fuel tanks.”
 

Air Force Magazine

 

Note that even aircraft that use drop tanks do not always have to use them in combat, especially where A-A tankers are available.

In Desert Storm F-16s of the 363rd FW(P) Forward deployed to King Khalid Military City AB in Saudi Arabia with A-10s meaning they could deploy with 4 x MK-84s as standard load-out with no drop tanks:

USAF F-16s at KKMC during the Storm - foreground is Block 25D #84-1257 of 17TFS  (USAF)

 

 

Fighters without drop tanks
Just to be awkward there have been a few fighters designed post Korean war that have not had the option of using Drop Tanks, these include the F-8 Crusader (non J), Su-27 Flanker, and the F-35 Lightning II.

F-8 Crusader (worldwars.net)

This means that when fully fueled on take off they have a much higher relative internal fuel load-out and weight because they are carrying the fuel that others carried in drop tanks. So, until the Su-27/F-35 get their fuel down to about 60% say their relative performance is significantly reduced in terms of subsonic climb, acceleration and overall turn performance. However, the lack of drag from large drop tanks will mean they can have better acceleration and higher practical speed through the transonic and supersonic regions of flight when only carrying light to no external stores. These jets also include fuel dump mechanisms that allow them to dump fuel for emergency situations such as an emergency landing.
With this approach you also need a very high thrust engine to overcome the extra fuselage size, weight and drag that was put there to hold the extra fuel in the first place.

Su-27 intercepts a Swedish ELINT aircaft (Swedish AF)

 

 

Are drop tanks really the best way of doing things?

• Valid arguments against include that they take up pylon space, can cause problems if they fail, and impose performance limitations on an aircraft.  Also some of the fuel in the drop tank is needed just to offset the extra weight and drag.
• Logistics of Drop Tanks can be an issue in terms of maintenance and getting enough to a squadron. Did any squadron ever run out of drop tanks post Korean War? [Answers on a post card because I am not aware of any on the Western side].
• Cost is another thing that is brought up, it is however much cheaper to jettison the tanks rather than lose the entire aircraft and pilot.

Any plus points?

• Rather good at extending range [duh]
• You can jettison them, unlike CFTs and bigger airframes.
• Erm….sometimes can be used to land on if they are empty and the gear fails [or you forget to lower it]:

F-16C Block 25 lands on tank at Luke AFB June 17 2004 (F-16.net)

 

 

 

The Future

Seems the arguments are mute because with F-22, J-20 and Su-57 using drop tanks, and talk of some being developed for F-35 they are not going anywhere in my lifetime.

Chegndu J-20 February 2017 (Elephant)

 

 

 

 

Sources
Thud Ridge (J.M.Broughton, 1969) Crecy Publishing
James Jabara (Sherman S 2001) online Acepilots.com http://acepilots.com/korea_jabara.html
Israeli Mirage and Nesher Aces (Alomi. S, 2004) Osprey Publishing
F-15E Strike Eagle Units in Combat 1990-2005 (Davies.S, 2005) Osprey Publishing
F-15C Eagle Units in Combat (Davies.S, 2005) Osprey Publishing
USAF F-4 Phantom II MiG Killers 1972 -73 (P.Davies, 2005) Osprey Publishing
Sukhoi Su-27 (Gordon.Y, 2007) Midland Publishing

Title Photo credit USAF

[Skyviper 1,101]

@MigBusterI've always wanted to know about this. Thank you so much for taking the time to write this report about it!

[+streakeagle 864]

It never almost never hurts to have the option to use drop tanks. It very much hurts if you need them but can't have them.

[Stratos 3,166]

Great report, I liked, and is very nice to see real life combat aviation articles here in CA. Good work MiGBuster!

[+Gepard 10,230]

One story i would add from Korea War.

When the MiG-15 entered the war, the supply situation with fuel tanks was bad. The soviet pilots got the order to drop the tanks only in emergency.

On November 8, 1950  a single flying MiG-15, piloted by S.Lt. Kharitonow was surprised by an attacking F-80, flown by 1Lt.Russel Brown. Shortly after oppening the fire 5 of 6 machine guns of the F-80 jammed, but some bullits hit the MiG-15. Kharitonow now aware, that he was attacked dropped the fuel tanks. As usual with the early MiG-15 drop tanks some fuel vapored. For the american pilot it must have been like a deadly hitten plane. But the MiG-15 dived down, accelerated and escaped.

For a long time in the western medias this was called the first jet to jet kill in history.

[TeargasHorse 287]

I struggle with loadout and consult my map in campaigns all the time about using a pylon for weapons or fuel. I began only flying from the most forward base available (not an option for RL AF ops). Something not mentioned, and I had not really thought about until I read the book, Yeager, was the use of the tanks as an incendiary device. The General and Bud Anderson in their P-51s, would drop their tanks on targets in Germany (after the escort was finished) and then strafe them to ignite the fuel!

I notice that when I ask my wingman to "attack my target" they drop tanks no matter what I ask them to attack, which makes sense (but I would rather they keep them until I either tell them to drop them or not, instead of telling them to radar on/off (what is that about??)). I ALWAYS keep tanks on un-contested bomb runs and dump them in A2A depending on the opponent (F-4 vs MiG-21 = yes, F-16 vs MiG-29 = after 3 turns, F-15 vs SU-27 =  YES YES SERPENTINE, SHELDON!!). Mostly it depends on how the fight goes after the missiles are gone, or useless (AIM-9B, this means you!). 

We have the luxury that, if we get out of the engagement area, we can warp home which uses no fuel. In RL we would tank, but the game (after 10 years) does not support that (maybe that IS what warp does?).  If I drop mine, they should drop theirs, otherwise, hold on to em.

What do you think?

[WallysWorld 2]

Many thanks for this interesting article. When flying SF2, I keep forgetting to drop them if I engage in air to air combat.

[MigBuster 2,861]

On 5/8/2018 at 5:45 PM, TeargasHorse said:

We have the luxury that, if we get out of the engagement area, we can warp home which uses no fuel. In RL we would tank, but the game (after 10 years) does not support that (maybe that IS what warp does?).  If I drop mine, they should drop theirs, otherwise, hold on to em.

What do you think?

 

Yes the warp is a handy refuel function I guess if you want to use your imagination.

I think always did that from SFP1 but don't fully remember, just another wonderful AI trait we have to put up with but you can understand the need to be simplistic in areas. You could change the logic e.g if an F-4 is asked to engage air its drops tanks but for A-G it doesn't without a command.

You could get into quite a bit of detail.........in Vietnam F-100s also used 335 Gal tanks a lot with a 390KIAS speed limit (with fuel) which maybe isn't so great going through a MiG infested area.

 

[fallenphoenix1986 603]

The F-8 could carry external tanks, it just generally didn't. Not sure if they were ever even fully cleared but at least the J model was built with points on the wings.

In the case of the F-35 I'd be surprised if they don't have the ability to mount ferry tanks in much the same manner as the F-22 does.

[MigBuster 2,861]

58 minutes ago, fallenphoenix1986 said:

The F-8 could carry external tanks, it just generally didn't. Not sure if they were ever even fully cleared but at least the J model was built with points on the wings.

In the case of the F-35 I'd be surprised if they don't have the ability to mount ferry tanks in much the same manner as the F-22 does.

Yes that is why it states (non J) above because from going through the flight manuals I couldn't find any evidence the others could carry them at all.

 

I can assure you there are no drop tanks for the F-35 currently only a rumor that Israel might develop some..they were originally dropped during SDD (System Dev and Demo ) stage apparently.

 

 

[fallenphoenix1986 603]

2 minutes ago, MigBuster said:

Yes that is why it states (non J) above because from going through the flight manuals I couldn't find any evidence the others could carry them at all.

I can assure you there are no drop tanks for the F-35 currently only a rumor that Israel might develop some..they were originally dropped during SDD (System Dev and Demo ) stage apparently.

Sorry missed that bit.

Like I said, I would be surprised if the f-35's don't have the capacity to have tanks fitted, if the Israelis are even thinking about it then the the wings and pylons must already be plumbed. If that's the case then its really only a matter of time until they show up as its only the tanks themselves to be developed..

[Danny79 1]

Awesome research! Thank you! So, the best SOP is to drop’em when in visual contact with the enemy. 

[ironroad 218]

On 5/12/2018 at 8:20 AM, fallenphoenix1986 said:

The F-8 could carry external tanks, it just generally didn't. Not sure if they were ever even fully cleared but at least the J model was built with points on the wings.

In the case of the F-35 I'd be surprised if they don't have the ability to mount ferry tanks in much the same manner as the F-22 does.

The J was re-manufactured from the ground up to have plumbing in the wings for tanks, but it was a pain for crews to load/unload them.

The re-modeled F-8K, L, H, and Ps did not have the plumbing.

As far as wing tanks go, Jane's F-15 always carried two wing tanks. In F-18 I always carried a center-line (for CAP) or two or three for deep-strike (leaving one station open for another weapon store). In F-18 online, tanks were never really needed.

For Lockon/DCS I normally carry two wing tanks in the F-15. I have done that so often and for so long, I have gotten use to flying with them and when I do punch them (last resort) I have to readjust to my stick's sensitivity settings and cut back on the burner.

Example of me training in a live fire exercise against a maneuvering QF-4 with full internal fuel and 1/2 full wing tanks. If I tried to pull such maneuvers against an F-5, F-16, or F-18 I would have been dead meat.

I

Edited May 15, 2018 by ironroad

[ironroad 218]

Might be on interest

http://tailspintopics.blogspot.com/2013/