Why did some British cold war era fighters have pylons for missiles on top of the wings, or in the electric lightings case fuel tanks?

[GreenKnight121]

I aways liked the look of the wing top missiles on the Sepcat Jaguar.
View attachment 759713
The over-wing pylons also are useful for system pods.
View attachment 759715
The Jaguar is one of my favourite aircraft of the 1980s. With its arrestor hook, good short runway capabilities, twin 30mm cannons and Martel antiship missiles, a squadron or two would have done nicely pre-war at the Falkland's.

I bet Ukraine could do wonders with the Jaguar even today.

Missed the bolded part before... it definitely tripped an alarm this time.

First I've heard of this... the normal comment I've heard about the Jaguar's runway performance is along the lines of "Jaguar takes off by the earth curving away below it".


Here is an interview with a former RAF Jaguar pilot (Peter Day*): I flew the Cold War Jaguar fighter-bomber
He gives a slightly differently-worded but essentially identical comment as mine above:

Describe the Jaguar in three words
"Comfortable, ergonomic, underpowered.
Complete this sentence: The Jaguar needed…
"More development in all areas."
What was the best thing about the Jaguar?
"Relative ease of day visual single seat operation at low level (LL)."
..and the worst?
"Lack of thrust."

Take-off/landing performance
"Landing first, easy, precise (⍺), brake parachute equipped with big brakes – excellent! Take-off has been variously described as due to the curvature of the earth and was certainly an Operations Manual reference event depending on entropy, configuration and airfield. Reliance on 'clear wing' after engine failure would be operationally standard. Full reheat was standard and operational formation take-offs would be a race to the first waypoint."

Did it have enough power?
"There was never enough power and the Adour, an Anglo/French cooperation, was optimised for high take-off thrust in reheat, good specific fuel consumption, providing a high speed dash capability and was to be changeable in 30 minutes! Good job there were two. Engine improvement were forthcoming including 'part throttle reheat' (PTR) to improve single engine handling, arguably also survivability, allowing reheat at less than maximum engine N1 rpm. Eventual Adour marks improved all engine performance aspects but there was rarely spare power, depending on the configuration."

Climb rate
"Totally weight and configuration dependent but the clean aircraft at 10 tonnes had a T/W of 0.5 similar to a Hawker Hunter, and climbed to 30,000ft in just over 1 minute. Fully war configured time to height was fairly pitiful and very fuel consuming."

* Peter Day's resume:
Jaguar Conversion Unit (226 OCU) Jun – Sep 1974
No 6 Sqn RAF Coltishall Oct 1974 – Apr 1977 'Flying Can-openers'
No 14 Sqn RAF Bruggen May 1977 – Aug 1980 'Crusaders'
HQ RAFG Jaguar Staff Officer Sep 1980 – Feb 1983
1500+ flight hours Jaguar

 

[EwenS]

Missed the bolded part before... it definitely tripped an alarm this time.

First I've heard of this... the normal comment I've heard about the Jaguar's runway performance is along the lines of "Jaguar takes off by the earth curving away below it".


Here is an interview with a former RAF Jaguar pilot (Peter Day*): I flew the Cold War Jaguar fighter-bomber
He gives a slightly differently-worded but essentially identical comment as mine above:




* Peter Day's resume:
Jaguar Conversion Unit (226 OCU) Jun – Sep 1974
No 6 Sqn RAF Coltishall Oct 1974 – Apr 1977 'Flying Can-openers'
No 14 Sqn RAF Bruggen May 1977 – Aug 1980 'Crusaders'
HQ RAFG Jaguar Staff Officer Sep 1980 – Feb 1983
1500+ flight hours Jaguar

Given Peter Day's experience as detailed it is unlikely that he experienced the 2 engine upgrades that were implemented during life of the Jaguar. In the 1970s the engine was the Adour 102 - 5,110lb dry & 7,300lb with reheat.

From about the end of 1983 they began to receive the Adour 104 which had 5,500lb dry thrust & 8,000lb with reheat. So nearly 10% more available at take off & 27% at high subsonic cruise.

Then in the late 1990s the Jaguar 3A were upgraded with the more powerful Adour 106 which 6,000lb dry & 8,430lb with reheat.

Indian production got the Adour 811 with 8,400lb with reheat.

So take off performance would depend on when the pilot making the claim was flying them.

 

[EwenS]

The last Jaguars in RAF service. 6 squadron disbanded on 31 May 2007

Aviation Photography- Jaguars retire

 

[buffnut453]

So take off performance would depend on when the pilot making the claim was flying them.

It also depends on where the aircraft were operating. During the summer at Incirlik, Turkey, the entire gorilla package was timed to take off early because of the Jag's poor hot-and-high performance. if launch was delayed by too much, then the Jags couldn't get airborne.

 

[Admiral Beez]

First I've heard of this... the normal comment I've heard about the Jaguar's runway performance is along the lines of "Jaguar takes off by the earth curving away below it".

Good info, and well cancels my idea for Jaguars at pre-war Stanley. I should have surmised that the Jaguar needed a lot of runway when at 2:20 they faded to black during a non-takeoff takeoff vid.


View: https://m.youtube.com/watch?v=zcEsxQRx_sI&pp=ygUWc2VwZWNhdCBqYWd1YXIgdGFrZW9mZg%3D%3D

Of course the best prewar strike or fighter aircraft to base a squadron at Stanley's short airfield is the RAF's Harrier GR3 or even better, the radar-equipped FAA SHAR. But neither had over wing missiles, so I'm OT.

 

[nuuumannn]

A funny anecdote I heard from an RAF bod once was that the Jaguar was the only RAF aircraft in which its take-off run was counted as a part of its combat radius...

One reason for the Jag's overwing pylons was because the inboard wing pylons were almost always occupied by fuel tanks, thus leaving only two wing pylons and a centreline one for armament.

 

[Admiral Beez]

A funny anecdote I heard from an RAF bod once was that the Jaguar was the only RAF aircraft in which its take-off run was counted as a part of its combat radius...

One reason for the Jag's overwing pylons was because the inboard wing pylons were almost always occupied by fuel tanks, thus leaving only two wing pylons and a centreline one for armament.

It's noteworthy that in the post-war era that aircraft designers omitted to include sufficient internal fuel load in almost every aircraft, and that engine designers could not provide sufficient fuel efficiency to permit allowance on internal fuel. Is there any Cold War supersonic fighter that could make do without external fuel tanks? The Lightning looks ridiculous with its over-wing tanks, but at least they're not occupying otherwise useful underwing pylons. Look at this F-15 below, now that's what wing pylons are for!

 

[EwenS]

Ever since the F-15C/D entered service the aircraft have been configured to carry the Conformal Fuel Tanks as shown in your photo. These are non-jettisonable which may or may not be an advantage. The slab sided engine intakes on the F-15 make it easier to design in but it has been done to others.

Conformal fuel tank - Wikipedia

en.m.wikipedia.org

 

[buffnut453]

It's noteworthy that in the post-war era that aircraft designers omitted to include sufficient internal fuel load in almost every aircraft, and that engine designers could not provide sufficient fuel efficiency to permit allowance on internal fuel. Is there any Cold War supersonic fighter that could make do without external fuel tanks? The Lightning looks ridiculous with its over-wing tanks, but at least they're not occupying otherwise useful underwing pylons. Look at this F-15 below, now that's what wing pylons are for!

View attachment 774116

Depends what you mean by "make do." Range is a function of mission profile, which was as true in 1944 as it is today. P-51 Mustangs could perform local air defence missions without drop tanks but they couldn't escort B-17s and B-24s over long ranges without them.

If the fighter's job is sitting on CAP, then you want lots of fuel to maximize on-station time, otherwise you're doing more frequent AAR (which takes aircraft off-station) or you're replacing the CAP assets more frequently (which eats aircraft utilization very rapidly).

Whatever range you design an aircraft to reach, I can guarantee you that there will always be a mission profile that requires longer range.

 

[Shortround6]

Whatever range you design an aircraft to reach, I can guarantee you that there will always be a mission profile that requires longer range.

True words.

 

[pbehn]

Whatever range you design an aircraft to reach, I can guarantee you that there will always be a mission profile that requires longer range.

With carrier borne aircraft the position of the carriers depends on the aircraft's range, which would rarely be enough for the captain of the carrier.

 

[Admiral Beez]

Whatever range you design an aircraft to reach, I can guarantee you that there will always be a mission profile that requires longer range.

True. But it does spoil the looks of a F-22 of F-35 to swing a pair or trio of drop tanks under the wings. I think somehow their designers sorted out how to conduct most missions on internal fuel, with AAR as needed. Perhaps supercruise helps. Do external tanks like the below impact the stealth capabilities?

This F-35 with six external tanks must be in a ferry role.

 

[Thumpalumpacus]

Ever since the F-15C/D entered service the aircraft have been configured to carry the Conformal Fuel Tanks as shown in your photo. These are non-jettisonable which may or may not be an advantage. The slab sided engine intakes on the F-15 make it easier to design in but it has been done to others.

Conformal fuel tank - Wikipedia

en.m.wikipedia.org

Small niggle: the conformal tanks were introduced with the -E model Strike Eagle, though they can be mounted on earlier models.

Perhaps BiffF15 could comment on the relative flight qualities?

 

[EwenS]

It's noteworthy that in the post-war era that aircraft designers omitted to include sufficient internal fuel load in almost every aircraft, and that engine designers could not provide sufficient fuel efficiency to permit allowance on internal fuel. Is there any Cold War supersonic fighter that could make do without external fuel tanks? The Lightning looks ridiculous with its over-wing tanks, but at least they're not occupying otherwise useful underwing pylons. Look at this F-15 below, now that's what wing pylons are for!

View attachment 774116

Small niggle: the conformal tanks were introduced with the -E model Strike Eagle, though they can be mounted on earlier models.

Perhaps BiffF15 could comment on the relative flight qualities?

CFT were previously known as FAST (Fuel and Sensor Tactical) packs. Developed in the early 1970s and first flown on an F-15B in 1974. The first F-15C flew in Feb 1979 and all production F-15C/D were equipped to carry them and did so from the introduction of those models in June 1980. 32nd TFS at Soesterberg in the Netherlands was the first to get the updated model.

The F-15E development started as a privately funded development in the late 1970s with a demonstrator first flying in July 1980 and the first production aircraft in 1986.

 

[Thumpalumpacus]

CFT were previously known as FAST (Fuel and Sensor Tactical) packs. Developed in the early 1970s and first flown on an F-15B in 1974. The first F-15C flew in Feb 1979 and all production F-15C/D were equipped to carry them and did so from the introduction of those models in June 1980. 32nd TFS at Soesterberg in the Netherlands was the first to get the updated model.

The F-15E development started as a privately funded development in the late 1970s with a demonstrator first flying in July 1980 and the first production aircraft in 1986.

Right, the Cs and Ds could carry them, but were not produced with them. The E introduced them as standard production features.

 

[BiffF15]

Small niggle: the conformal tanks were introduced with the -E model Strike Eagle, though they can be mounted on earlier models.

Perhaps BiffF15 could comment on the relative flight qualities?

Thump,
Smaller niggle, the CFTs (Conformal Fuel Tanks) were introduced on and delivered with every F-15C/D bought by the USAF. The Israelis have retrofitted their A & B models to accept CFTs.

Iceland based F-15Cs were the last USAF unit to use them. Eventually they were scrapped I think due to maintenance costs. They held approximately 5k each in fuel while the external tanks held roughly 4K each. The big difference is the externals are jettison-able (lower drag and weight instantaneously) while you have to fight with possibly unwanted fuel on board in the case of the CFT.

While I haven't flown with CFTs, I do have friends who did. The word is better pitch authority at slow speeds, and negligible drag penalties at high speeds.

In my opinion If they still existed we would be flying with them.

Cheers,
Biff

 

[Thumpalumpacus]

Thump,
Smaller niggle, the CFTs (Conformal Fuel Tanks) were introduced on and delivered with every F-15C/D bought by the USAF.

I didn't realize the frames shipped with the tanks. Thanks for the correction.

Thanks too for the insights.

 

[GTX]

This F-35 with six external tanks must be in a ferry role.

View attachment 774121

Photoshop

 

[GreenKnight121]

This F-35 with six external tanks must be in a ferry role.

View attachment 774121

Photoshop

Specifically, the CFTs are F-16 CFTs. I also doubt the F-35 would be cleared for outer drop tanks.

True. But it does spoil the looks of a F-22 of F-35 to swing a pair or trio of drop tanks under the wings. I think somehow their designers sorted out how to conduct most missions on internal fuel, with AAR as needed. Perhaps supercruise helps. Do external tanks like the below impact the stealth capabilities?

View attachment 774120

Yes, they would... which is why new drop tanks have been designed for the F-22.

F-22 Low Drag Tank and Pylon (LDTP) - USAF poster for upgrades:

And a pic from last month:

F-22 Raptor Photographed With New Stealthy External Fuel Tanks

The new fuel tanks are part of a package of upgrades announced in 2022. Two years after the upgrades were announced, we might have the first glimpse of

theaviationist.com

Note that those are flatter and wider than the stealthy sensor pods revealed January this year:

 

[nuuumannn]

It's noteworthy that in the post-war era that aircraft designers omitted to include sufficient internal fuel load in almost every aircraft, and that engine designers could not provide sufficient fuel efficiency to permit allowance on internal fuel. Is there any Cold War supersonic fighter that could make do without external fuel tanks? The Lightning looks ridiculous with its over-wing tanks, but at least they're not occupying otherwise useful underwing pylons.

Let's not forget that back in the 50s and 60s, IFR on a massive scale was evolving and only the USAF could afford to field large numbers of tankers, the RAF did have tankers of course, as the Lightning was fitted with a probe, but the RAF's requirements and therefore number of tankers did not match anything like the USAF had. Because of this, external tanks were a necessity. The difference between Britain and the USA is that in a European conflict, Britain was within spitting distance of the combat zone and therefore expediency was the key. Organising IFR sorties following a QRA strike package departure means time is wasted, so jets go with what they can carry. When flying from the USA, the USAF has extensive tanker support for a mission package, or alternatively it can expeditiously depart from Britain, which again means the jet takes with it what it can carry rather than waste precious time tanking. Longer range missions are different of course, look at El Dorado Canyon, for example, but the expediency level is different than it would have been if the Soviets invaded the two Germanys, which were presumed to be the epicentre of the battleground.

Comparing an F-15E Strike Eagle with a 1970s era Jaguar is futile for several reasons, foremost being the growing sophistication of electronics in that time, which enable more sophisticated weapons and a larger number being carried by a given platform, and several conflicts that transpired between the Jag entering service and the mods to enable the F-15E to carry what it does in that image, which all resulted from and in a different appreciation of what constitutes a modern battlefield scenario.