Is the Tornado GR4 still supersonic?
 

I know the RAF states that the Tornado can go at M2.2 but with the airframe alterations on the GR4 (laser designators and changes to the air intakes?) can and does the aircraft still fly at supersonic speeds?

Thanks all.

what change to the intakes (assuming it isnt classified)?

I was under the impression that there had been an alteration or inhibiting of something called the 'variable geometry intake ramps' in the early 80's.

Although this could easily be a load of tosh.

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.

So would a operational GR4 go over M1.0 ?

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

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.

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!

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

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

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).

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.

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.

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

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

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.

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

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.

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

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.