Is the Tornado GR4 still supersonic? [Archive]

spectre150

24th Oct 2006, 14:32

The GR1 was designed, I think, with supersonic intakes which included hydraulic ramps which influenced the airflow into the engines at high speed. AFAIR, the 'RAMPS' were inhibited from the very early days. We used to do a supersonic run at TTTE (clean jets, not even pylons) but once you put tanks, ECM, CBLS or real weapons on there was not much need for supersonic ramps (bloody thing wanted to M1+ at Goose aand Nellis though :rolleyes: )

Supersonic intakes and the hydrailic ramp mechanisms seemed like a lot of unnecessary weight to carry round but it was probably more expensive to replace them.

whatdoesthisbuttondo

24th Oct 2006, 14:50

So would a operational GR4 go over M1.0 ?

NoseGunner

24th Oct 2006, 14:53

Surprisingly, I think everything above is correct!

The GR1/4 does not have functioning ramps. However, the ramps (if they were functioning) do not start to move until about M1.3 so don't actually make a difference until then.

A GR4 will still go super but as you hang more stuff off it it becomes harder and harder, until at some point it can't. Additionally many stores may have a VNE or MNE that limits the ac to a slower speed than it may be capable of. I guess a GR4 guy could give more details.

As an example from the F3 world the M fit tanks have a subsonic limit on them but definitely do go super (I've seen it, but not done it, honest!). The F3 also does have functioning ramps, and they have a noticeable affect as soon as they move - giving decent M1.3 onwards acceleration.
Even old, bent F3s can still get to Mach 2 with inboard pylons and stubs fitted. Clean ones certainly quicker, but of course that isnt allowed so noone has done it.:}

Hope that helps

GlosMikeP

24th Oct 2006, 14:53

The GR1 was designed, I think, with supersonic intakes which included hydraulic ramps which influenced the airflow into the engines at high speed. AFAIR, the 'RAMPS' were inhibited from the very early days. :rolleyes: )

Supersonic intakes and the hydrailic ramp mechanisms seemed like a lot of unnecessary weight to carry round but it was probably more expensive to replace them.
Tricky. I suppose it depends on how fast you could 'really' go with a typical load as to whether the ramps would be necessary to keep the shock positioned upstream far enough of the compressor. If it naturally stayed in an OK posuition, no need for the ramps I guess.

NoseGunner

24th Oct 2006, 14:56

By operational you mean with anywhere near standard, useful loadout and tank fit I think the answer would be no. And if it could, it wouldn't get very far before it needed a tanker!

Safeware

24th Oct 2006, 15:01

Previously, IIRC the AICS (Air Intake Control System) was inhibited on GR1 after all the bits were put under the nose. These bits disturbed the airflow and imposed some limits. As F3s needed AICS, and GR1s didn't, I believe most were removed from GR1s to stock up the F3s.

But that was 10+ yrs ago. and the GR4 may be quite different in that respect.

sw

whatdoesthisbuttondo

24th Oct 2006, 15:17

So when the BBC states that the Gr4 can 'fly at supersonic speeds', they are correct but only if lightly loaded?

Vasco XV

24th Oct 2006, 18:03

Tricky. I suppose it depends on how fast you could 'really' go with a typical load as to whether the ramps would be necessary to keep the shock positioned upstream far enough of the compressor. If it naturally stayed in an OK posuition, no need for the ramps I guess.

A fixed geometry intake will only work efficiently at its design Mach no. At any off-design point, sub-critical or super-critical operation will occur when the oblique shock is not positioned on the cowl lip, because the shock angle depends on Mach no. For aircraft which operate over a wide range of Mach nos, the penalties imposed by a fixed geometry intakes can be unacceptable. :8

The Tornado was initially fitted with ramps (ie variable geometry intakes) to position the oblique shock wave on the cowl lip of the intake. They were indeed scheduled to work above Mach 1.3. The ramps were a pain in the ass because they frequently leaked hydraulic fluid and it was normally an arduous task to repair. As with everything, the cost of continually repairing the ramps outweighed the benefits of having them so we stopped having them.

Asking a question such as "can the GR4 go supersonic?" generates a million answers, the shortest of which is "yes!"

It will go supersonic in almost any fit at any level with reheat engaged. As has already been mentioned, each store has a mach / IAS speed limit - that does not mean that they cannot go supersonic when strapped to the jet, they just shouldn't.

Obviously, if you had to make a sharp exit, it would be bye bye to the stores and the clean jet would go supersonic and some (but I think that 2.2M is unrealistic at low level).

GlosMikeP

24th Oct 2006, 19:17

The Tornado was initially fitted with ramps (ie variable geometry intakes) to position the oblique shock wave on the cowl lip of the intake. They were indeed scheduled to work above Mach 1.3. The ramps were a pain in the ass because they frequently leaked hydraulic fluid and it was normally an arduous task to repair. As with everything, the cost of continually repairing the ramps outweighed the benefits of having them so we stopped having them.

Thanks, this is the bit where I couldn't see what was happening.

It's obvious it's got to choke to get the pressure recovery but I just couldn't see how anyone could design an intake to choke in one place at all speeds without something moving. What I could see was a limited speed range with fixed geo.

Nicely explained.

ukmil

25th Oct 2006, 21:57

ok, my point of view on this, being a tornado engineer. The GR4 can no longer go supersonic. in fact, i was carrying out the AICs inhibit mod at St Athan on the Gr1 in 1994. The Ramp actuators were removed and replaced with steel rods. The actual electrical system remained intact, and the CB's tripped.

However, there was a problem some years after, where the steel rods were causing cracks in the intake frames, so some gr's had actutors put back in, but the system is still inhibited. A GR is only capable of greater than 1.3M, with outboard stores removed, and as they never fly in that config, it is not required

You might even see some F3's with the outboard pylons, as part of the trial sead mod, these were also lim'd to subsonic, as the extra stress caused by the loads on the ends of the wing were too great.

Safeware

25th Oct 2006, 22:45

UKMIL,
You might even see some F3's with the outboard pylons, as part of the trial sead modF3s had o/b pylons back in the mid 90s.
sw

HUDcripple

26th Oct 2006, 03:11

Typical Canuck, I had to take a GR-4 (the XV Sqn air display spare) super at low level east of Leuchars on the way home from an airshow...:p

...yes, I complied with all the orders and it was authorized.;)

...Of course, it wasn't much ~1.05ish

HC

BEagle

26th Oct 2006, 05:26

My, my, the short range subsonic bomber known as GR4 is clearly a huge advance over the real bombers we used to have...... Buccaneer and Vulcan.

NoseGunner

26th Oct 2006, 05:33

Gout keeping you up? Wrong side of bed? Decided on early morning fishing trip? :bored:

ukmil

26th Oct 2006, 16:05

F3s had o/b pylons back in the mid 90s.
sw

yes they did, but not all, only a select few were comlpeted, and there is still one or two now, that have them fitted. i was involved with the Mod in the mid 90's fitting to outboard pylon links.

ARINC

26th Oct 2006, 16:13

From Memory the whole point of the ramps was to maintain subsonic airflow over the compressor (0.5 mach I seem to remember as being the figure always quoted) regardless of Aircraft Mach. The ramp movement was scheduled using a small pitot probe in the intake itself sensing purely intake airspeed.

The intakes did this on the GR1 despite having the ramp cb's pulled because the unmodified intake profile was sufficent to slow the intake air down (upto, again from memory, about 1.5 Mach aircraft speed)

No idea about GR4 Ramps

kitwe

26th Oct 2006, 17:44

I was led to believe (by BWOS) that, in the early 80s, the installation of the laser fairing on the GR1 made one of the engines (the right one? ) rather prone to surging at lowish Mach 1+ speeds (I don't know whether this figure was classified so I can't be more precise). Perhaps the FLIR fairing on the GR4 had the same effect on the other engine? Whatever, the TTTE Tornados, not being fitted with those fairings would not have had the same problem.

ukmil

26th Oct 2006, 18:25

they did have a small impact, but the main thing with TTTE is they flew CLEAN, with no pylons

kitwe

26th Oct 2006, 18:38

Perhaps I did not make myself clear. Regardless of whether TTTE Tornados flew with pylons or not, all I was trying to suggest was that,since they did not have laser fairings, they would not be prone to engine surges caused by such fairings. BTW, UK Mil, what is a "small fact"?

Spugford

26th Oct 2006, 19:20

ukmil... wrong.

GR4... very definitely supersonic when stores removed.

:ok:

kitwe

26th Oct 2006, 19:37

UK Mil

You say in your initial post that the GR4 will not go above Mach 1.3.....Surely, in anybody's language, that is definitely supersonic! Also, one of the benefits of hanging stores on the outboard pylons of an F3 was that it was determined to actually relieve stress on the wing. Perhaps some of the aerodynamicists will explain this.

Anorak removed!

L Peacock

26th Oct 2006, 20:15

UK MIL is generally in the ballpark.

After the introduction of the LRMTS (and associated reduction in Vne), active ramps only bought an extra nought point very small Mach, whether clean or not. Hardly worth the additional complexity and maintenance, so they were deleted.

Clean (or even with O/B stores) GRs are still supersonic.

L Peacock

26th Oct 2006, 20:55

kitwe

not an aerodynamicist but I'll have a go.
A weight of say 300kg at the end of the wing will require just 300kg of extra lift to maintain level flight. However, at the wing root, for say a 4m wing, the upward bending stresses will be reduced by 300x4 (1200)kg/metres.
Effect even greater under g.

Have I got this right boffins?

the_flying_cop

27th Oct 2006, 05:32

this one certainly isnt supersonic
http://newsimg.bbc.co.uk/media/images/42238000/jpg/_42238404_tornado.203.jpg

meant as a bit of a giggle. was great to hear the crew were safe etc etc, go safely all of you.

kitwe

27th Oct 2006, 15:18

L Peacock

Please check your PMs.

Eric Aldrovandi

27th Oct 2006, 23:31

not an aerodynamicist but I'll have a go.
A weight of say 300kg at the end of the wing will require just 300kg of extra lift to maintain level flight. However, at the wing root, for say a 4m wing, the upward bending stresses will be reduced by 300x4 (1200)kg/metres.
Effect even greater under g.

Ai, not bad, it's all about bending moments baby - more like mechanical engineering than aerodynamics though! I believe the effect is known as "nodal progression" and the outboard stores stop the ends of the wings flapping up and down like something that flaps up and down a lot :8

Incidently, the fuel in the wings helps to prevent torsional flexing so it remains in the wings for as long as possible to reduce fatigue.

ok, my point of view on this, being a tornado engineer. The GR4 can no longer go supersonic. in fact, i was carrying out the AICs inhibit mod at St Athan on the Gr1 in 1994. The Ramp actuators were removed and replaced with steel rods. The actual electrical system remained intact, and the CB's tripped.

However, there was a problem some years after, where the steel rods were causing cracks in the intake frames, so some gr's had actutors put back in, but the system is still inhibited. A GR is only capable of greater than 1.3M, with outboard stores removed, and as they never fly in that config, it is not required

Ukmil - are you sure you're a Tornado engineer? You sound more like a mechanic or technician if you were involved with inhibiting supersonic ramps... Anyway, you may find reading the Release to Service interesting - you can look up the speed limits for each different fit. In 10 fit (outboards but no tanks) it is supersonic and some!

Max Reheat

28th Oct 2006, 10:06

Just a quick note for what it's worth.
Back in Apr 1994, Goose Bay, with the Vicar in the back seat a couple of GR1 chaps got tapped by 2 CF-18s. Well the GR1 guys did the honourable thing and 'Ran away bravely!' Combat burner down a dry river bed with the Vicar twisted round in his seat shouting 'faster, faster!' When just before some kind of nodding PIO started the nose gunner saw 725 IAS in the HUD. Sorry, didn't have the capacity to select Mach. I guess the OAT was around 0 deg C.
I seem to recall the jets were in (would it be) B11 fit, ie 2 Hindenburger tanks, BOZ, ECM and 2 CBLS. Also seem to recall that Vmo in that fit was around 595 KIAS with the wings in 67.
Thank God I'm still alive! Thank God I'm out!!!!
Cheers... Max
ps Regards to Vicar, Cheese, Cas, Bunter, Sammy, JT, JP, Chaz and all the others unfortunate enough to be terrified by me!!:eek: :E

kitwe

28th Oct 2006, 10:18

I can't be entirely sure about the GRs but the F3 was/is capable of speeds much higher than the RTS upper limits. Lack of engine thrust is not a problem with the F3 and it will still accelerate above 800kts IAS (clean).

BEagle

28th Oct 2006, 11:22

Rumour hath it that some mate decided to have a go at the 'wot'll she do, mister' competition a few years ago in a F3. Full chat, pull to the vertical, establish a very gentle push as the thing passed FL lots - then it went a bit pear shaped. Double flame out, no pressurisation, battery power only.... But he got it down OK.

Then, so the rumour goes, Ba$tard Bill tried to hang him out to dry for grossly exceeding the RTS. Until, that is, someone happened to mention that surely Lightning reheat rotation take-offs were also outside the RTS and hadn't 'certain Air Officers' done such things when they were his age....

Whereupon it all went rather quiet....:cool:

Samuel

28th Oct 2006, 13:28

All very technical and complicated, but why would you want to do those sorts of speeds, for any reason? When would it be either desirable or necessary for a Tonka operationally?

A2QFI

28th Oct 2006, 13:32

I think that B*ll had something to do with lifting and realigning a few roofs in the Farnborough area, around showtime one year and in an F4!

Respected and admired by all who do not know him well!

kitwe

28th Oct 2006, 15:50

Samuel

When I flew Tornados at very high speeds, it was during development trials from Boscombe Down. At that time, there was no RTS so we had to test the aircraft so that MOD(PE) could make Service Release Recommendations to the RAF. We flew under Airworthiness Flight Limitations (AWFLS) promulgated by BAe/Panavia.

Samuel

28th Oct 2006, 20:30

Thank you Kitwe, I understand that, and the enthusiasm of the "I wonder what she'll do" people who have always existed and long may they and their enthusiasm be around, but given all the reasons on this thread, there seem to be none which would include supersonic speed as a best option.

If I carry a pack and with the knowledge that I know where I'm going and what it's going to take to get there, when I come to a hill I don't increase speed and run up it, because then I might not get where I'm going!

Max Reheat

29th Oct 2006, 00:38

Trust me Samuel, I think you'll find supersonic very practical when there's an enemy fighter at 4000m in your 6!

Samuel

29th Oct 2006, 01:47

I do Max[trust you], and I guess you can never have too much power, but that wasn't the question, and I gather from the answers that, while it is possible, it doesn't happen too often for a variety of reasons. Given the circumstance you describe, and adding the factor that you have everything hanging that can hang, would you be able to accelerate fast enough?

kitwe

29th Oct 2006, 09:13

Samuel

Max has hit the nail on the head. Although there can be few excuses for deliberately exceeeding Vne in peacetime, there will be occasions (such as the baddie with hostile intent in your 6) in times of tension/war when the only way to save your aircraft and your life is to park the throttles in the top left corner and run. If required, you can always jettison those stores that are limiting your speed/acceleration. In your example, if a 7ft tall baddie with murderous intent and armed with an axe was closing on you as you climbed your hill, would you not consider jettisoning your pack and running away?

Samuel

29th Oct 2006, 14:51

Very much so! And downhill, albeit subxonic with my legs!

Thank you both for your explanations.

skyhigh

29th Oct 2006, 16:19

Feel i have to reply on this one. UK MIL, I can't believe that you have anything to do with GR4 as surely you should know that the GR4 can still go super and still does especially in Cyprus on ACT dets. The fairings etc have all made a difference undoubtably but the FIn still can go supersonic without to much of a drama. The fits that can go super (RtoS cleared) are 0 Fit i.e. clean with or without pylons and missiles or 10 Fit, i.e. addition of outboard stores.

The amount of rubbish I have read about this matter on this thread is amazing especially from people who profess to be knowledgable. Incidentally the jet can go super with tanks on but is not cleared!

Max speed is however limited to M1.3 (RtoS)

LowObservable

31st Oct 2006, 17:36

Explains why the RAF was (so they say) pretty interested in the subsonic A-12 Avenger II, alias the Flying Dorito, before the current Veep took it to see Dr Winchester.
I talked to an F-15E pilot once who said that the highest M he'd ever seen on the type was 1.2.

Ewan Whosearmy

31st Oct 2006, 22:32

I talked to an F-15E pilot once who said that the highest M he'd ever seen on the type was 1.2.

The F-15E's original LANTIRN target pod is limited to .9 MACH before aerodynamic heating gets the better of it; that's the real limfac. Other than that, with the more powerful PW-229 motors the jets at Lakenheath have, the F-15E will quite happily supercruise.

LowObservable

1st Nov 2006, 01:35

I'm sure it will - but given the mission, when do you train for that? How high a priority is it?

LOMCEVAK

4th Nov 2006, 14:36

GR4s are taken to 1.25M on post maintenance flight tests (I cannot remember what the F3 is taken to). The 2250l tanks are cleared supersonic on the F3 but not the GR4, although structurally there is no reason why the clearance could not have been obtained for the GR1/4; it just was not needed.

There is a somewhat excessive use of the adjective "easily" on this thread when applied to the speeds which the Tornado can achieve. Yes, an F3 can reach 800 KCAS and 2.0M, but with stub pylons and missiles I would add a slightly more conservative tone!

The last remaining GR1, ZA326, achieve 709 KCAS/1.06M at low level on its penultimate sortie (7 pylons), but this required a shallow dive. Unfortunately, a R THROT caption precluded squeezing any more out of it!

Brain Potter

4th Nov 2006, 16:01

I thought that to be genuinely supersonic all the airflow over the airframe had to be greater than the local speed of sound. This does not occur until an aircraft speed of around M1.4 and therefore the band M0.8 to M1.3 is regarded as transonic. This is a dim recollection from undergraduate aerodynamics and I am open to correction.

I recently looked up some old Farnborough airshow clips on britishpathe. Aircraft top speed really did seem to be a huge selling point in those days. For example the Buccaneer is referred to as a "slowcoach" compared to the Phantom. Whilst this is correct in a game of Top Trumps the operational difference is not so clear-cut. It makes you wonder if some of the poor procurement decisions were made on the basis of headline performance figures that are all but irrelevant to the real world. Did their Airships regard M2.0 performance as a holy grail at the expense of range/payload in practical conditions?

ex-ranker

5th Nov 2006, 16:33

Just to clear up:

GR4's DO NOT have intake ramps fitted.

Various MOD's have been carried out on frame x=8000 to carry the steel Jury struts in place, and stop them cracking the support structure.

At least the GR1 intake ramp actuators removed made a nice spares stock for the F3's!!!

The Rocket

5th Nov 2006, 17:46

Just to clear up:
GR4's DO NOT have intake ramps fitted.

I'm sure that when you meant to put everyone straight, in such an authoritative manner, you actually meant

GR4's DO NOT have Functional intake ramps fitted.

As you can be assured that the ramps are still very much there on every GR4 that I have ever seen.

L Peacock

5th Nov 2006, 18:47

Rocket

Almost posted the same but managed to control my pedantic alter ego:ok:

ex-ranker

6th Nov 2006, 16:49

I'm sure that when you meant to put everyone straight, in such an authoritative manner, you actually meant

GR4's DO NOT have Functional intake ramps fitted.

As you can be assured that the ramps are still very much there on every GR4 that I have ever seen.

Apologies to all I offended by my duff gen.

I meant to say "GR4's do not have intake ramp ACTUATORS fitted"

they do however, as correctly stated have intake ramps, as we are constanlty modifying the support bracket for the jury strut.

Once again I apologise for my outburst, Ill proof read all posts before submitting in future, thanks for putting me straight in an authoritative manner.

The Rocket

6th Nov 2006, 21:54

ex-ranker

7th Nov 2006, 13:48

No problems whatsoever old chap. :p

Welcome to the Pprune school of Pedantry ;)

Slightly intrigued by your comments about the modification of the support brackets for the strut however. I was under the impression, rightly or wrongly, that the brackets although subject to frequent NDT testing, are actually fairly sound, and that this is more a process of monitoring than actually modifying. :confused:

However, I am more than happy to be corrected on this issue, as I in no way profess to be an expert on the matter.

thanks Rocket,

Yes, the brackets and frame x-8000 are subject to NDT mainly at primary star maintenance, however many of the GR4 updated airframes (even after subsequent major) have a GR1 mounting bracket and locking mechanisms fitted (Hi-LOK fasteners and a redundant, actuator support bracket.) the MOD is relatively simple (or it might even be an RTI now):

'Remove old support bracket, remove HI-LOKs and recover aircraft'.

However the HI-LOKS are sometimes a complete nightmare to remove without damaging surrounding structure (they either shear off at the base or are stuck fast so you need to "pursuade" them out). So not a nice job especially as every GR4 i've come across, this MOD/RTI still needs doing! :ugh:

hopefully this is an insight (not a preach or lecture!) as to mechanics of the GR4 ramps.

oh, dont get me started on Kruegar flaps!:\