Perhaps I can add to the discussion here on the possibility of an A/B mix:
I've posted previously about this idea, and the numbers all depend on operational and fleet planning assumptions.
Operational assumptions should be fairly simple - what is the Force Elements At Readiness (FEAR) (the old terminology I admit) requirement? Can be succinctly set out as x number of aircraft capable of y set of roles, at z days/ weeks/ months of readiness. I suppose you could add capable of ops over a set number of days.
Back in the days when I was managing the Sea Harrier fleet, our Flag Officer always published updated FEAR requirements every 6 months, with any short term adjustments required for mod programmes or so forth. The key element for us was to have two front line squadrons of 8 jets at R2 (48 hours) to embark on a carrier for 6 months of ops. We expected one squadron to always be at sea, with the other at sea for around 40% of the year.
The training/OCU unit was at at longer period of notice for embarkation., around a month.
Looking at the F-35 fleet, my very rough estimate would be that from approximately 140 aircraft, around 70 F-35Bs would be required to produce 4 front line squadrons of about 12 plus an OCU of around 10. That would leave 12 aircraft in the sustainment fleet, about 17% of the total, which should be plenty. I would be aiming for two squadrons embarked at sea at any one time (24 jets) with the other 24 at around a month's notice.
Key point - the embarked jets aren't 'deployed' - they are operating from their main base. A large carrier like the QE class is built to support those jets and their personnel for long periods, providing very nearly the same support as available on a UK land base. In some ways, it's better - you get more work out of your embarked personnel than you do ashore. The difference between planning for 'embarked time' and 'deployments' is significant.
Similar sums might apply to an F-35A/C fleet, in my view. Historically, the UK military has been satisfied with very low levels of operational availability. In many cases, this has been due to mismanagement of the aircraft fleets, where successive mod and update programmes have been allowed to dilute the fleet to the point where only a small fraction of the fleet have actually been capable of operational use.
In other cases, the in service authorities have adopted servicing regimes that guarantee having a large number of aircraft being taken to bits all the time. A certain well known UK military helicopter has a contractor run support system that frequently advertises its many successes - I'm not surprised, as at any one time 25% of the fleet are being serviced. Christ on a bike, I could have kept a fleet of JCBs in the air if I'd had one quarter of the fleet guaranteed as a servicing 'float'.
As far as an F-35A/C choice goes, I'd suggest that the determinants could be range and AAR method. If the RAF really wants a long range bomber, the F-35C would seem to be the best choice - but it would be a fairly expensive option compared with the A. Then there's the problem of the F-35A's AAR receptacle. A study was done to look at making the probe and drogue standard fit across the F-35 fleet, and a think a RAND study found that there would be advantages in making the USAF restrict the boom system to the large aircraft it was optimised for.
Certainly, on the F-35A, the AAR boom receptacle takes up a lot of fuel tank volume (about 600 pounds as I remember) and adds a lot of weight, as the receptacle has to fairly stout to resist boom loads - it ends up being mainly steel. Again relying on memory, but I think going from boom receptacle to probe on the A was calculated to add around 50 miles to the combat radius.
As ever, it will be down to the clever folk up in town dealing with the Treasury.
Best regards as ever to those doing the long term costings, or whatever they are called now....
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