Over at Think Defence the admin has produced a very comprehensive post on the possible features of the future Type 26 frigate. From experience I can tell you that such an article takes an astounding amount of time to put together, predominantly because of the demands for accurate research followed by the difficulty in finding the right words to express your opinion. Even the process of typing itself is laborious; this paragraph alone has taken me nearly five minutes to type, even with a 50-60 word per minute typing speed, partly due to the need to go back and edit mistakes and re-write sentences till they make the most sense.
So on that note I take my hat off to him. I however, wish to take this debate down a slightly different path.
As you might expect a debate has been raging back and forth in the comments section of that article as everyone wonders what equipment will be included, what capabilities the ships will bring to the table, what performance characteristics they will demonstrate, and of course in this age of austerity, how much will they cost? Should it just be an Anti-Submarine Warfare (ASW) Frigate? Should it carry "strike length" missile cells for using the Tomahawk Land Attack Missile (TLAM)? Does it need a main gun, and if so what size?
And it's that cost/capability balance that I want to peer at for a little why.
Not just in ships though. For several decades now we've seen the rise of the multi-role/swing-role aircraft, and on the ground we've seen various companies try to capture the utilitarian spirit of vehicles such as the Willy's Jeep and the M113 armoured personnel carrier with "families" of light and medium vehicles.
It's all the rage in the modern world and not without reason. Common platforms capable of performing multiple roles can save a hefty packet of money and inconvenience. The common supply chain of a "family" of vehicles is designed to reduce the burden on logistical forces, leverage savings from the supplier through high volume production, and reduce the cost of training support personnel who only have to learn to repair and maintain one set of spares.
On top of this support saving, you also have reduced cost in the initial purchase and front line training. If you only build one aircraft to cover a wide range of combat roles, then you only have to spend once every twenty to thirty years on development. You can order a high number of aircraft/ships/vehicles that will leverage a significant saving in the initial production costs (through construction efficiency) and you only have to train your front line users such as pilots/drivers/helmsman on one set of systems, instead of concurrently training multiple streams.
At least that's the theory. There are two potential problems with this approach;
1) Just how much of a saving is actually generated?
2) How much capability is lost?
Perhaps one of the better illustrative examples of multi-role equipment replacing single role equipment was the US Navy's decision to adopt the F-18E/F Super Hornet as its primary fighter and attack aircraft, along with the EA-18G "Growler" electronic warfare variant.
The list of aircraft previously used by the US Navy to fulfil the various roles now taken on by the Hornet/Growler combination is quite impressive (though not all were operated simultaneously); A-1 Skyraider for Close Air Support (CAS), A-4 Skyhawk for light attack, A-6 Intruder for medium attack, KA-6 Intruder for "buddy" tanking, EA-6 Prowler for electronic warfare, A-7 Corsair/F-4 Phantom/F-14 Tomcat for air superiority, and the S-3 Viking in the Anti-Surface Warfare (ASuW) role. Additionally the Hornet will take over the Suppression/Destruction of Enemy Air Defences (SEAD & DEAD respectively) roles from aircraft such as the Skyhawk and Phantom.
When first implemented it was estimated that this would save the US Navy between $1-2 billion annually. The question is how much of that saving has actually been realised, and at what cost in capability?
Without hard figures it's difficult to tell, not least because one of the savings that such programs make is invariably to reduce the number of airframes (literally the total number, not just different types) which is sort of a dishonest saving in a sense, as you could just as easily reduce the fleet size of the previous aircraft and achieve the same effect.
Then you have to consider the savings offered simply by replacing old with new. New engines are designed to be more fuel efficient and benefit from advances in technology and design that make them more reliable. New airframes are typically constructed of lighter materials, further improving efficiency. And new equipment simply doesn't have the wear and tear on it that old equipment does, requiring the old kit to be serviced and tweaked on a more regular basis.
Next is the issue of commonality. This argument would tend to heavily favour the F-18 and in general you can't argue too much. But you can argue a little.
The A-6 Intruder for example was powered by the Pratt & Whitney J52, which was also used in the KA-6, EA-6, and the A-4 Skyhawk. The F-4 Phantom was powered by the General Electric J79, which was also used on aircraft like the F-104 Starfighter and the IAI Kfir (Israel). The F-14 Tomcat was powered by a General Electric F110, also used on the F-15 Eagle and F-16 Fighting Falcon.
The high production runs brought about by planning across the whole fleet, and indeed across the whole spectrum of US defence (see, Congress can be useful for some things) means that the impact of having a single aircraft type now across the whole US Navy is somewhat reduced.
Then we have to consider what might be termed "dead weight", for want of a better term. The F-18E/F Hornet carries - like most modern fighters - an X-band radar designed for air to air combat. The radar is there to detect, track and engage airborne enemy targets at Beyond Visual Range (BVR). But all the while that the aircraft is conducting ground attack missions, the radar's utility is somewhat reduced.
This issue is less apparent in modern Active Electronically Scanned Array (AESA) radars, which are demonstrating the secondary capability to be used both passively as radar warning receivers, and also as communications relays, receiving and then re-transmitting data as part of a wider, connected information network.
Still it does beg the question; does every aircraft need a radar? An aircraft that is used predominantly in the attack role could save both initial purchasing costs and continued running costs by deleting this very expensive piece of kit. Similarly, attack aircraft tend to use smaller, less powerful engines, as the need for high speeds/high power is greatly diminished.
This extends into the general design of such aircraft. An attack aircraft generally requires different characteristics compared to a fighter. Fighters need to be fast and highly agile, often favouring sleek, low drag designs for supersonic flight that often have the side effect of reducing fuel capacity, and in the modern era it is almost unthinkable that a fighter would be built without being designed to be inherently unstable, requiring complex (and stunningly expensive) fly-by-wire systems to help the pilot control the aircraft.
By comparison, dedicated attack aircraft tend to be built the other way; inherently stable, without the need for complex fly-by-wire systems, and designed for subsonic cruising with heavy payloads and without much attention paid to supersonic performance, and generally with a greater provision for carrying fuel internally for long missions.
This of course is not an absolute rule, such as demonstrated by aircraft like the Panavia Tornado and SEPECAT Jaguar, both of which were eventually designed for high speed, low altitude penetration of enemy defences.
The question does have to be asked though; are the commonality savings generated by having a single fleet (such as Typhoon) actually offset due to the "over engineering" of large chunks of the fleet when performing tasks other than the very high end fighter roles? Operations over Afghanistan for example can and are being managed by aircraft less advanced than Typhoon.
Swapping hats though for a moment and joining the opposite side, supporters of multi-role aircraft would argue that aircraft like Typhoon reduce the need for so many airframes in theatre and give commanders greater flexibility.
Let's say hypothetically you deployed 12 aircraft to a theatre, with eight active and four reserve aircraft. Those eight aircraft can initially conduct Combat Air Patrols (CAP) armed with a full air to air weapons load and drop tanks for additional range. Once the threat of enemy aircraft has diminished by whatever means, some of those eight aircraft (or even all of them) can switch to attack operations. Theoretically, as swing role aircraft, they can go armed to carry out either role, especially thanks to the unique design of Typhoon that permits the carriage of four BVR missiles without interfering with the main wing pylons.
If you didn't have Typhoon, the alternative would be to deploy 6 fighters and 6 bombers, possibly working all of them to the limit. Assuming you only used four active (with two spare) from each group, that would severely restrict the ability of the force to conduct and/or contribute to CAP missions and then later strike missions.
Thus, in order for single role (we'll leave out ancillary missions like reconnaissance for now) aircraft to be viable, they would have to cost around half what a multi-role aircraft does. Even if we discount development costs for two aircraft types versus one, and the need for two pilots versus one, it's going to be a serious struggle to achieve those kind of economies.
You'd have to build around a relatively cheaper engine like the Rolls Royce Turbomeca Adour, as used in the Hawk trainer. For the fighter you could try and build a modern version of something like a MiG-21 (from an aesthetic perspective one of my favourite aircraft), but you would inherit the same sort of problems that aircraft has; short range, low weapons carriage and little room for a radar.
Perhaps you could integrate some of the design features of the Typhoon by having pylons blended into the body for BVR weapons while short range missiles were carried under the wings, but you're still going to struggle to find room for fuel and the radar would have to be a small job (you'd be lucky to get one comparable to the F-16 in there).
God only knows what you'd do for the attack version. Perhaps a wider winged version of the Hawk with the second seat replaced by a fuel tank? Will the engine cope with all that added weight? It's certainly a dilemma that would appear to favour the multi-role/swing-role aircraft in practice.
What about ships? Here I'm gradually starting to think that swing role favours the Naval environment even more. With aircraft there is at least the balancing act that can take place with size and speed, allowing a smaller aircraft to achieve comparable speeds to a larger one as long as the design and power-to-weight ratio is taken into account, as well as a larger margin of error for allowing some aircraft to fly slower than others.
Ships have a more difficult time of this, not least because neither an ASW ship or an Anti-Air Warfare (AAW) ship can afford to slack too much on the high end speed. These ships, at least as the Royal Navy requires them to be used, need to be able to achieve long ranges without constant refuelling. Thus given the size of the engines, the size of the fuel storage, and the size of the crew, it's almost impossible to build a small ASW or AAW ship to Royal Navy specifications.
So now we have either our ASW or AAW ship ready for its own task, what now separates it from serving in the others role? In the case of the Type 45 she isn't optimised from a sound perspective to conduct the ASW role, which means she would be relatively easier to detect for hostile submarines, and lacks the ability to carry and deploy a towed sonar like the Type 2087.
Looking at the designs for the Type 26, which is optimised for quieter running and for towing sonar arrays, what now stands in the way of her performing the AAW role? The answer would be that she lacks the Type 45's Principal Anti-Air Missile System (PAAMS), consisting of the more expensive and capable SAMPSON radar, the S1850M long range/wide area search radar, the combat management centre and the provision for carrying the Aster family of air defence missiles.
Thus it would appear that the future for the Royal Navy may very well be found in combining the two ships into one design. Essentially we would be talking about a Type 26 that replaced its currently planned Artisan radar with something like the SAMPSON (which BAE claims does not require back up like the S1850M), the Type 45's combat management centre, and Sylver silos to accommodate Aster 30 medium range weapons.
Of course this would reduce the number of ships needed in service as it would combine the two roles, but that takes us back to the perennial problem of having enough ships to fulfil all of the required tasks. Making one ship or one plane perform two roles is fine and can save you money, but in order to realise that saving their has to be a reduction in the fleet size. At a time when those in the RAF and Royal Navy are complaining that their numbers are being pushed too low, multi-rolling may actually be detrimental to their long term capability.
Firmly on the ground, things get more complicated. No land vehicle is really multi-role or swing role in the same sense as an aircraft or ship. You can have a common platform on which many variants are based, but it's not really possible to have an ambulance that's also a mobile command post, that's also a recce vehicle, that's also an anti-tank vehicle.
In theory you could build a vehicle that can be quickly switched from one role to another, in the same way that aircraft can change out their payload on returning to base and thus effectively switch roles, but it's not especially an ideal circumstance. Typically vehicles are going to be on the move constantly during a campaign, away from any formal servicing area, fulfilling specific tasks for the battle group that offer little opportunity or indeed need to flex back and forth.
It's perhaps here that specialisation and single rolling for vehicles has the most capability benefit, especially if you can use a common engine or drive train to reduce down some of the support costs. Of course just to be a fly in the ointment, this is also the place where a common platform finds its greatest financial leverage as production runs can reach into the thousands.
In conclusion, it's not an enviable job by any means to be someone that has to work on these kind of projects. The trade offs from building a reduced number of expensive, multi purpose platforms versus cheaper, but very focused platforms seems to vary strongly between the various air, sea and land domains, while the number of platforms required seems to also have a large impact on whether one can afford to take the single purpose versus multi purpose route, but only up to a point where the very high volume production would swing back to favouring multi purpose equipment. Total force numbers and whether they can be reduced or must stay the same adds an additional layer of complexity.