Jaguar performance

[GrahamEM]

Jaguar enthusiasts & experts to the ready..........

1. Why does the Jaguar have double rear wheels for such a light jet ?, while the Tornado GR4 fully laden has single rear wheels.

2. How for such a light jet does it only do 800+ mph max, when it's got twin jet engines ?

thanks

[Gary West]

Jaguar enthusiasts & experts to the ready..........

1 - The Jaguar has double wheels because it was designed to operate from rough strips - given the scenario that most runways would be knocked out. Jaguars were trialled and occassionally seen on grass strips.

2. Tougher question, but it's down to the aircrafts design and power of the engines. In case you didn't know, the Jaguars use the same engine as the BAe Hawk (Ardour) but with after burners basically.

Edited December 3, 2007 by Gary West

[GrahamEM]

Thanks Gary, i knew you'd be along with the answers

i knew they were Ardour but didn't know they were used in Hawks, thanks.

[Notdoneyet]

Jaguar enthusiasts & experts to the ready..........

1. Why does the Jaguar have double rear wheels for such a light jet ?, while the Tornado GR4 fully laden has single rear wheels.

thanks

Graham,

The Jaguar was designed to operate from unprepared airstrips (fields, motorways/autobahns etc) in the eventuality of a conflict with the Soviet Union. Hence the sturdy u/c forgings and the double wheels to absorb the greater landing and take off loads. There was a thread on here a while ago with pics of Jags landing/taking off from grass strips and motorways IIRC.

HTH,

Ian

[Nimrod Dave]

IIRC correctly the Jag has always been plagued by heat problems with regard to the engines. It's well known for being a jet where energy management was critical, definately not one to yank the stick on. I believe the correct term for the levers in the cockpit of the jag was 'variable noise levers'...

[dahut]

Jaguar enthusiasts & experts to the ready..........

2. How for such a light jet does it only do 800+ mph max, when it's got twin jet engines ?

thanks

The rough airfield/wider wheelprint has been covered already, so I'll keep mum on that. As for the speed concerns, what precisely is wrong with 800+ mph? The Jag, if you'll recall was designed as a multimission/strike interdiction aricraft:

"The Jaguar program began in the early 1960s, in response to a British requirement for an advanced supersonic jet trainer, and a French need for a cheap, subsonic dual role trainer and attack aircraft with good short field performance. From these apparently disparate aims would come a single and entirely different aircraft: relatively high-tech, supersonic, and optimised for ground attack in a high-threat environment."

We're not talking about high altitude, zoom-fast fighter intercept here. This is a dirt mover and a high precision bomber! Now, let it be said that it has also developed into a flying electronics platform over three decades, with both full protection, counter measures and target acquisition suites at it's disposal. This speaks volumes about the adaptability and "stretch" found in the Jaguar and, I might add, in all great designs.

The Jaguar carries a broad range of ordnance and cannon to do its work, with a maximum speed of Mach 1.6 (Mach 1.1 at sea level) and hardpoints fitted for an external weapons load of up to 10,000 lb (4,500 kg). That doubles the normal 4-5 thousand pound load of a B-17!

But, it is no laggard in the air-to-air mode and can carry along AA missiles, independent of it's ground attack ordnance, should the need arise to protect itself against aerial enemies.

While England, the home of it's birth, has eschewed the Jaguar as outdated, India, at least, has not. That nation is modernizing its current Jaguar's and placed an order for 29 MORE upgraded Jaguar IM aircraft from it's own indigenous Hindustan Aeronautics in 2005. They are upgrading the engines for better reliability and performance at mid to high level while they wait for their Medium Combat Aircraft (MCA) competition to deliver the Jag's replacement - the expected delivery dates for which have been pushed out to 2020. Meanwhile, the Indian Jaguars will soldier on.

Altogether, not too bad for an aircraft that "only" manages 800+ mph, eh?

As one might expect, this whole discussion reminds me of a joke:

There were once two bulls. One was an old, wisened fellow with hooves well worn from years. The other was a sprigthly yearling, always abluster and full of himself. One day the two of them were under the big tree atop the hill, taking the shade. Suddenly, the youngster jumps up and begins to dance around the old bull, shouting:

"C'mon, gramps, this is killing me. Lets run down the hill, right away, and hit us one of them heifers!"

The old fellow looks up at him, looks down the hill at the ladies and responds slowly, still chewing his cud:

"Tell you what, kid...why, don't we walk down there and hit em ALL?"

Speed aint necessarily bad, but it aint everything.

Edited December 3, 2007 by dahut

[Antoine]

In the French AdA, it was said of the Jaguar (At least by non-Jaguar pilots) that the aircraft could take off only because the earth was round...

I must say that French jaguar engines were never updated.

[Gary West]

While England, the home of it's birth,

but a French led design

[Col.]

While England, the home of it's birth,

I think you mean Britain.

[Gary West]

I think you mean Britain.

that'll be GREAT Britain actually

[Col.]

that'll be GREAT Britain actually

Glad you're so impressed with it Gary!

[dahut]

I think you mean Britain.

Of course, I did. Picking nits, are we?!

Shall we go a step further and say it was a joint design, with the French in as partners with GREATEST of Britains?

According to Wikepedia:

"Cross-channel negotiations led to the formation of SEPECAT (the Société Européenne de Production de l'Avion d'École de Combat et d'Appui Tactique) in 1966 as a joint venture between Bréguet—now Dassault Aviation—and the British Aircraft Corporation to produce the airframe, and a separate teaming of Rolls-Royce and Turboméca to develop the Adour afterburning turbofan engine. Though based in part on the Breguet 121, using the same basic configuration and an innovative French designed landing gear, the Jaguar as built also incorporated major elements designed by BAC - notably the wing and high lift devices.

The first of 8 prototypes flew on September 8, 1968. It was an orthodox single-seat, swept-wing, twin-engine design but with tall landing gear. It had a maximum take-off weight in the 15 tonne class and could manage a combat radius on internal fuel alone of 850 km..."

SO, to all our "amis Francais," please do not feel slighted by my earlier comments. I am but a bloody thick Yank, and it seems I have much to learn.

Edited December 3, 2007 by dahut

[Gary West]

But unless all my research is wrong - which I should think is highly unlikely - the BRITS, ie, people from GREAT Britain, were in the vanguard on the Jaguar

david - your first post in Italics is basically what happened, the UK & France having unique needs, then joining up to develop what became the Jag. However, the design which was selected was Breguets Br121. If you think back to the design period, early 60's, the Jag does look more French than what was coming out of Hawker Siddley - Mirage III etc. Britain won the export rights though, remembering that at the same time, Puma, Lynx & Gazelle were all joint collaberations. Lynx, being the other British controlled export model.

[MikeC]

Which station in RAF Germany had both Jags and Buccaneers - was it Bruggen or Laarbruch? Anyway, 'tis said that one day a notice appeared to the effect that Jaguar pilots were requested not to taxi in Reheat.

[Gary West]

Which station in RAF Germany had both Jags and Buccaneers - was it Bruggen or Laarbruch? Anyway, 'tis said that one day a notice appeared to the effect that Jaguar pilots were requested not to taxi in Reheat.

Thought the bricks were only ever at Laarbruch, and the Jaguars only at Bruggen?

[Mentalguru]

that'll be GREAT Britain actually

I think it shoud be changed to GREAT ENGLAND

[Gary West]

In the red corned we have from England, Mental and in the blue corner from Scotland, we have Col.......a clean fight please gentlemen

[WolvoWill]

The Jag has always been notorious for being underpowered - it has the unusual ability to light the afterburners when at part throttle (on most other aircraft the afterburners can only be turned on when the engines are operating at maximum 'dry' thrust).

This part throttle reheat was necessary as (depending on fuel and weapons load, and altitude, temperature humidity etc) an engine failure could leave the Jag struggling to maintain altitude and speed, and when it came to landing the jet with one engine out, the lack of responsiveness with dry power meant a way of getting extra thrust quickly when at lower than max dry power settings was necessary as otherwise the approach could be very hairy indeed.

Without part throttle reheat if you got too low or slow on an engine out approach, in the Jag you wouldnt necessarily have the grunt to climb out using dry power on your one remaining engine, or the time to wait for the engines to spool to 100% and light the burners...

The jag also had some 'interesting' high AoA handling characteristics as well - it was rather underfinned (a mistake not made for the Tornado ), and as such tended to lose directional stability rather abrubtly above 16 degrees AoA!

I love the Jag but its a jet not without its flaws! A tricky beast to fly for sure compared to some of the more powerful, 'carefree handling' types which came later!

Edited December 3, 2007 by WolvoWill

[Col.]

I think it shoud be changed to GREAT ENGLAND

Right you, outside. Now.

In the red corned we have from England, Mental and in the blue corner from Scotland, we have Col.......a clean fight please gentlemen

Clean my bottom, I'm putting on a kilt and bringing ma claymore! Just give me a minute to watch the highlights out of Braveheart and I'll be ready

[speedy]

I've got a picture somewhere, where a fully loaded Jag is in reheat behind a Tristar refuelling. Must be going out as fast as its going in!

[GrahamEM]

Also the Harrier has a single jet engine and goes as fast if not faster than the Jaguar with side nozzles and not pointing directly out the rear which you'd think would be more restrictive for forward force

[Col.]

I've got a picture somewhere, where a fully loaded Jag is in reheat behind a Tristar refuelling. Must be going out as fast as its going in!

Guess that's one way of venting the fuel tanks.

[Neil]

Small bit of Jag trivia. I have it on good authority that the 2-seaters, T2's/T4's, were just fractionally faster than the single seaters, streamlining coming into effect.

[Col.]

Small bit of Jag trivia. I have it on good authority that the 2-seaters, T2's/T4's, were just fractionally faster than the single seaters, streamlining coming into effect.

I've heard a similar story about the two-hole Lightning, the aerodynamics were different but the end result gave the same drag factor as the single-seat machines.

[dahut]

david - your first post in Italics is basically what happened, the UK & France having unique needs, then joining up to develop what became the Jag. However, the design which was selected was Breguets Br121. If you think back to the design period, early 60's, the Jag does look more French than what was coming out of Hawker Siddley - Mirage III etc. Britain won the export rights though, remembering that at the same time, Puma, Lynx & Gazelle were all joint collaberations. Lynx, being the other British controlled export model.

I was wrong on that, which is why I amended it. I hadda check that no sooner than I printed it. I found nothing to indicate the Brits swoggled the French to come along on the deal. Somewhere I picked that up, a figment of my fetid imagination, no doubt. Each group, Anglo's and Saxons, brought its own part to the table, as you indicate. SO, I hadda toss that bit in the bin.

Now I read here that the Jag was an anemic, underpowered gas bag. Go figgure.