Forum: General F-35 Forum

I'm curious how the stealth and sensor capabilities of the F-35 stack up with the modern stealth destroyers that are being produced around the world, such as the Type 45, Horizon, Zumwalt (although it is not in service yet) and others. Who get's spotted first?

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That's a complex question. I assume the destroyer, even with stealth, has a much larger RCS than the frontal aspect of an F-35. However, it has an infinitely more powerful radar so is able to put more energy into a beam at much longer range.

So you would need to know the RCS of the ship at different aspects, the RCS of the F-35, and the beam power of both radars. Then there's signal processing. How small a signal can you reliably pick out? Then there's AWACS. Is the battle group travelling with that capability? Where is it stationed with respect to the F-35? What are the capabilities and ranges of the weapons each side will employ for attack and defense? It's very complicated.

There are large facilities staffed with smart people, computers, battle analysis software, intel staff, tacticians, etc. who set out to model and answer these questions. It's not a trivial exercise.

destroid wrote:

I'm curious how the stealth and sensor capabilities of the F-35 stack up with the modern stealth destroyers that are being produced around the world, such as the Type 45, Horizon, Zumwalt (although it is not in service yet) and others. Who get's spotted first?

Those ships are all over 100 metres long. The F-35 is 15 meters long....

Who do you reckon is going to get spotted first? The Earth (according to most) is round. Not flat. Why that's important is because when you're stuck on the ground the atmosphere curves and prevents you seeing beyond a certain distance at ground level. A conventional air search radar or an IRST system has the same problem. At ground level they can't see beyond the horizon either.

The easiest way to push back the horizon and see further is to raise your radar or IRST sensor further up into the air. When you stand on a mountain you can see a much greater distance then you can when you stand on a beach. So it is with radars.

Now whilst I've acknowledged recently that the F-35 isn't the hottest physical performer around, I'm sure even it's most strident critic would (reluctantly perhaps) admit that it's more capable at taking it's sensors higher up in the air then a Zumwalt Class Destroyer or a T45 Destroyer would be.

Therefore the F-35 is likely to have the radar horizon advantage over a surface ship. They've got much bigger and more powerful radars, but are blocked by radar horizon limitations. The F-35 has got smaller less powerful sensors. But it is not limited by radar horizon concerns and it's much smaller physically.

The real problem however is that as a ship can only manage about 30 knots at top speed, whilst an F-35 can manage about 700 knots at top speed, a ship finds it extremely difficult to run away from an air based threat. Consequently they have hugely powerful radars constantly scanning the sky looking for threats and an overlapping system of defences to protect themselves from threats. Those radars blaring away will be picked up by the F-35's electronic warfare sysytems, long before the F-35 could likely detect these ships on it's radar and well beyond visual range, even taking magnification devices into account.

Therefore I think it pretty much a given that the F-35 would detect those freakin huge Destroyers sitting in the middle of the ocean, long before an individual destroyer could possibly detect the F-35...

Well put Conan!
I've heard that the F-35 and AEGIS destroyers can exchange information with their respective radars, wonder what that adds to the equation?

FlightDreamz wrote:

Well put Conan!
I've heard that the F-35 and AEGIS destroyers can exchange information with their respective radars, wonder what that adds to the equation?

Tons. It's also the same reason why Destroyers that want to survive don't work alone either. They extend their radar horizons by having multiple ships spread out and air support available, all networked together to provide a common recognised air picture of the battlespace they happen to be inhabiting...

That's the systems side of things that people on the internetz don't really care about because it's not as straightforward as saying things like, "my marketing literature says my fighter of choice has a 900mm diameter radar dish whilst yours only has an 800mm dish and as we all know aperture size equals power output (everything being equal everywhere of course...) therefore my fighter wins and your country is doomed for not picking it..."

Er, it's a bit more complicated than that...

Last edited by Meteor on Nov 25, 2011 - 10:19 PM; edited 1 time in total

Conan; Except for OTH-B radars, all radars are limited by line-of-sight (LOS) as you stated. If you're behind a mountain range or below the curvature of the Earth horizon, both players are invisible to each other. However, if either player climbs up to LOS to achieve radar contact, that player is then, by definition, in LOS of its target. In your example, as soon as the F-35 climbs above the radar horizon to find the ship, the aircraft becomes theoretically visible to the ship's radar. At that point effective radiated power (ERP) becomes a major factor in acquisiton, and a ship will almost always have more ERP available than an aircraft. It also has a far greater radar jamming capability, both in barrage and smart jamming techniques. The ship is also down at sea level embedded in a relatively warm and humid environment. Water severely attenuates IR range. On the other hand, the aircraft is up in very cold and dry air, which makes it stand out in the IR spectrum.

When we used to do TASMO or MAROPS in the F-4 and F-16 (20+ years ago) we were very dependent on off-board targeting. We knew that a suface-action-group (SAG) had a far greater radar range, ESM, ECM and ECCM than we did. A P-3, B-52, E-2 or E-3 would locate the SAG from 100+ miles out at high altitude, stand off out of SAM range, then pass the SAG location to us inbound strike aircraft down at very low level behind the radar horizon. We tried not to emit anything because we knew the SAG ESM would detect us. Once we broke the radar horizon at 10-15 NM from the SAG we knew they saw us, so at that point we lit up our radars, which were usually instantly overwhelmed by the SAG ECM. If the vis was poor (or at night) which happens a lot over the water, we'd beam around aimlessly until we were "kill removed."

Clearly stealth brings something to the equation, which is why I suspect the Chinese will use the J-20 to go after USN SAGs. However, a modern, fully equipped SAG, especially a USN attack carrier task force, is a very difficult nut for fighter aircraft to attack. That will remain the case even with the F-35. I say leave it to the Virginia class SSNs.

Conan, I may be retard, but if the f-35 can see the destroyer, than the destroyer can see he f-35. Radar is LOS. Everything is LOS that is used for auq, and tgting. What am i missing? Is this thread about attacking a carrier group? hmmm...stealth, decoys, and a sh*t ton of cruise missles.

If A is in position to see B, then B is in position to see A, but there is a way that height/altitude does give a plane an advantage: in a fighter-versus-fighter discussion, it would be called "kinematics". The ranges of the plane's missiles & bombs are lengthened by having gravity working for them, and the ship's missiles' ranges are shortened by needing to fight gravity.

The first to employ their radar gets detected first.
As for IR, I think the destroyer puts out more heat.

The surface ship has the advantage of being on the surface with surface clutter but ground clutter shouldn't be a problem anymore these days. The F-35 is higher in the air so it will be more visible from the surface at longer ranges. I don't really know who would get spotted first on radar really but for IR the ship will definitely be putting out a much larger IR signature. The Ship may have a more powerful radar but again its radar is limited by the horizon while the F-35 can see farther due to being higher in the air.

I would imagine a next-gen surface ship will have a good ESM system so both may detect themselves at the same time if they turn their radars on.

Well, let's constrain the scenarios. Let us say that an F-35 is looking to engage the destroyer (with whatever weapon you like). The F-35 knows the approximate location of the destroyer, but does not have support from GPS, AWACS etc. Assume fuel is not an issue.

To show you the complexity of reality, the smart play is for the F-35 to communicate the ships position to the battle group, who may well call in a submarine attack on the destroyer. Modern torpedoes are devastating. Even from quite a distance (60+ miles) a sub can launch Harpoons. Why risk your aircraft when you can attack much more safely from underwater?

Realistically, destroyers and cruisers don't go far on their own, they move in naval formations with ships protecting each other and augmenting each others capabilities. The simple scenario you're describing - a lone F-35 hunting a lone destroyer - doesn't really exist.

Not every navy is the USN. Destroyers are the largest ships in plenty of navies around the world. Regardless, the question is more about their respective stealth and radar systems, could the F-35 spot the destroyer without being spotted in turn and engaged? Could it spot from outside the engagement range of the destroyers (up to 240km or so depending on the specific missile)?

The primary sensor for finding ships is going to be the ESM of the F-35. There are just so many EM sources on a ship (besides the radar looking for the F-35) that the ESM equipment will find the ship long before the ship sees the F-35.

LOS affects both true, however ship's radar heights are a fixed maximum height. Radar range performance isn't the same as theoretical line of sght due to radar propagation in the atmosphere. Due to the ships height being fixed, but the F-35's altitude being variable, I'd assess the F-35's detection range performance potential as greater overall.

Forum: General F-35 Forum

F-35 and stealth destroyers?