Was thinking the same. The French PA2 using the same hull would have been a conventional design. For that kind of money and size why limit yourself to STOVL? Let alone the performance trade off between the F35B and the F35C?

Dear All,

Thank you for your positive comments - it's nice to know that my posts help a little here and there. Also thank to those who responded with their posts - exchange of ideas is always a good thing. I'd like to respond to those, and hopefully help the thread along.

LO raises the very good examples of Rafale and the F-111 as aircraft designed from the outset to be both CTOL (land based) and CV (cat and trap carrier based). The F-111B CV variant proved to be unsuccessful, and when I worked at Fort Worth it was frequently quoted as an example of how not to put an aircraft to sea. It couldn't 'thread the needle' of being able to get a reasonable payload off the catapult (very high empty weight) or get back on board at a feasible speed (not enough wing). It shows what an excellent job the French made with Rafale, although I would like to know just how common the airframes are between the land based variants and the 'M'.

The reason I mention that is to pick up on LO's point about empty weights, and the effect on them of going STOVL. He is absolutely right that the empty weight of the F-35B is higher than that of the F-35A, and he is also right that the 'B' has to carry around the weight of the equipment to get it on and off the ship. However, I would gently point out that the F-35C also carries some weight to allow it to use the launch and recovery gear (the cats and traps) on the ship. Using the 'empty weight' figures from the 2016 OT&E report, the three variants come out as follows (figures slightly rounded to make the mental maths easier):

F-35A - 29,000 pounds
F-35B - 32,400 pounds
F-35C - 34,580 pounds

From these, the F-35B's 'STOVL weight penalty' is around 3,400 pounds, The F-35C, however, has a weigh penalty of 5,580 pounds. This is due to the factors I highlighted in an earlier reply, where the unique loads generated by cat and trap operations generate massive additional stresses that have to be managed by additional or much beefier bits of metal. The F-35C also has to have larger wings, fins and tailplanes to be able to do that slow precision approach and landing stuff as well as flying away from a catapult launch. Plus a landing gear system that weighs well over twice that of an A. These all add many pounds. The designers I worked with told me that the 'C' model was the least 'common' of the three variants. I freely admit that this isn't a straight comparison - those bigger wings on the 'C' do translate into increased internal fuel capacity and longer range. However, they also mean lower speeds and reduced turn performance - the 'C' model bleeds energy in the turn faster than the A or the B. Horses for courses, as ever. By the way, the 'C' also lacks an internal gun and has, I can assure you all, a very aggressively lightened structure, just like the other two variants.

To pick up on LO's last point - yes, STOVL does let you operate from smaller ships. I can't quite follow the rest of his argument (which is my fault, not his), but I would gently offer the observation that the USMC have a bit of a handle on what they are doing (just like the USAF, the USN, the RAF, the RN and other F-35 operators) and they are not putting 12 or 13 F-35Bs on an LHA and sending it out east for the look of the thing.

As an engineer, I would not want to get too far into CONOPs matters such as raised by Easy Street. I do think, though, that he raises a valid point about UK F-35 force structure, and the fact that we are planning for an 'all B' force with consequent effect on our F-35 ops from land bases. I've previously posted my opinion that a split A/B force could be a better option for the UK. There is quite a bit of commonality between the A and the B, especially where many of the normal support related costs drivers apply (e.g. training, avionics spares and sustainment, systems components), and a split A/B force, working off a common training and support system would, in my view, be worth looking at. Along with that, I would suggest that the 'Forward' A and B aircraft could then be returned to their proper Force Command HQs (Air and Sea), thus restoring the proper chains of responsibility for operational development and not least air safety responsibilities.

Finally, (and sorry for the long post) a gentle reminder (at least from my addled memory) of the CVF/F-35 historical relationship and SDR 2010. The F-35B STOVL variant was, up to that time, the UK's focus, coming out of the initial Naval Air Staff Target for a Sea Harrier replacement to operate from 'Invincible' class ships, and also because STOVL expertise was the UK's main bargaining chip to get full 'Tier 1' partner status on the JSF programme. (The formal UK/US document that got the UK on to JSF was actually titled the 'STOVL MoU'). However, from the outset, the UK wanted to keep all options open for the CVF future carrier, and mandated a ship large enough to be converted to cat and trap. This led to two very large carriers, almost as big as the USN's 'Forrestal', which was the first of the 'super carriers'. This decision was also influenced by the view (not at all wrong) that much smaller carriers (like the 20,000 ton Invincibles) suffered from serious constraints on internal space for fuel, weapons and hangarage. However, with over 40 years' since the last time anyone in the UK had tried to design a ship of this class and size, the MoD had a few gaps in their technical expertise, especially at higher levels.

That mattered, because when SDR 2010 came around (and I know quite a few people of all 3 services who tell me that the 2010 SDR was one of the most fouled up Defence Reviews of all time), the problems the F-35B was then having caused what I can only call a 'panic'. This led to high priced people in Mod Main deciding that the UK should go 'cat and trap' - after all, how hard could it be to convert the (already designed) CVF? They'd watched the spiffing Carrier Alliance videos showing how you could just peel off the deck and install the cats, after all. I know for a fact that this decision was taken without input from the Carrier team - the two star in charge was given under 48 hours (over a weekend) to come up with the costs to justify the decision.

In the event, when reality dawned, including the actual state of progress on EMALS at that time and the complexity of a conversion of CVF back to cat and trap (NWSRG is exactly right when he calls it 'open heart surgery'), the decision was reversed in 2012, I think. Was it the right decision to go back to STOVL? Time will tell, but I think (my view only) it was. When you start to add up the real costs of operating an effectively sized cat and trap fleet of aircraft including the need for tankers (not so much for strike range, but as essential safety measures to refuel aircraft waiting to recover while a fouled deck is cleared), the long range AEW, special personnel to man and operate and repair the cat and trap gear, the training load for the pilots, and so on, I honestly believe that the UK can't get into that game and do it properly. It's only the USN that can do it, at present. But hey, I'm just an old engineer.

Thanks to all those who have helped this become such an informative and enjoyable thread. And who have put up so kindly with my ramblings. I'll go quiet now for a bit.

Best regards as ever to our young men and women who are out right there now on land and at sea working hard and professionally to give the UK the defence capability it needs and deserves.

Engines

Apparently reports
 

of the Russian navy hunting Big Liz down.

X10 submerged assets on their way from Kola..

Engines, thanks for the education.

Re U.K. all F35B, land and sea use, presumably this should enable the aircraft to ‘ski’ off road bridges and ‘land’ in the hole in the woods if future land strategy requires. i.e. a more flexible aircraft against increased wt, aka Harrier.

Also we tend the think that more weapons = more weight, which could be changing with new lighter technologies, except someone requires more range, more weapons, more … , or even a mini stealth AEW.

Engines, you omitted the other main drawback of that fat wing on the F-35C, the much slower acceleration.

The acceleration of the F-35C from M0.8 to M1.2M is 27 seconds slower than the B and 35 seconds slower than the A; and acceleration up to M1.6 consumes almost all internal fuel.....

ORAC,

Breaking my 'go quiet' rule only to say thank you. Yes, you are quite right, the F-35C is really a lot slower to go supersonic and it does burn fuel - bigger wings and tails will do that. (Curse those pesky laws of physics). Incidentally, as part of the 2004/5 weight reduction effort, I believe that LM were looking at removing some internal fuel tank capacity from the C, as it was showing a predicted range way above the KPP figures. I don't know if that went ahead, though. If they did, that would be quite an unusual design decision - but it shows how important the weight reduction programme was for all 3 variants, not just the B.

One lesson I've learned on my journey through aircraft engineering is this - getting aircraft to be able to do 'cat and trap' operations is way, way harder than the USN makes it look. Getting aircraft to do it and be operationally effective is even harder than that. Being operationally effective at sea at night in bad weather is even harder than THAT.

Best Regards as ever to all those doing just that right now.

Engines

Just a few quick points:

tdracer/Wondering

The UK intends to operate a joint RN/RAF force, this is not tied exclusively to the carriers. For conventional CV aircraft that would mean a high training burden to keep everyone carrier qualified. In 1982 1 Sqn RAF were able to embark Harrier GR3 aboard HMS Hermes because they are V/STOL aircraft, and because the ship was up to speed with operating jets.

Additional catapults and arresting gear mean more expensive equipment to be integrated and maintained, and more manpower. The SDSR 10 cuts slashed naval manpower without much thought, Cameron wimped out of increasing RN (and RAF) manpower in 2015.

Lastly, STOVL carrier operations are less sensitive to whether than old style CV ones. The QEC design is smaller than the US carrier and would have not had the same operating limits with F-35C, however with F-35B they probably can.

Easy Street

One possible NATO scenario puts a UK carrier based ASW task group (with NATO frigates and SSKs) in the Eastern Atlantic and/or GIUK gap to conduct task group ASW (Merlins with dipping sonar, frigates (and destroyers) with towed array (and hull mounted) sonar and submarines as part of the task group. Meanwhile the F-35B can counter Bears, Backfires, and so on.

See: Fire and Ice - A New Maritime Strategy for NATO's Northern Flank

The UK has committed a carrier capability to NATO, and this seems similar to the Cold War and the roles of CVS/Sea Harrier/Sea King.

Engines
 

Hi Engines - you seem to know what is going on in this programme - (program for our cousins!)

I emerge from hibernation because you have offered information that was unknown to me before.

I had previously believed that we (the UK) should have bought the C and put launch and arrester gear on the QE/PoW. That way we could have operated from land or afloat without major penalty.

The B/STOVL version was, in my opinion, a Harrier/Invincible legacy that was inappropriate for current requirements.

The Harrier austere landing site concept was brilliant and worked well in its time, but it required essential and substantial support from the Royal Engineers, Signals folk and many others. That infrastructure worked really well in Germany in the 70's/80's but it has now all gone. I know the USMC position and fully understand and support their need for the B and its austere potential, but I am not sure that we either need or could afford that option.

So if the value of STOVL is now just to allow aircraft to operate from QE/PoW, then perhaps the C might have been better.

But the variations suggested about the C might make me think that my views that we should have bought the C rather than the B are wrong. Interoperability with the USN and French notwithstanding.

It all doesn't really matter now as things are well down the track, but it would make me feel better to know that my prejudices are wrong and that our esteemed politicians and their advisers were right all the time!

I would much appreciate your views.

Yes, I know that this is now the favoured narrative among carrier supporters, hence my comment about 'blue water ops'. And it's absolutely not what the Government had in mind when it agreed to invest billions in the carrier strike concept. Sure, the strategic picture has changed since the late 2000s and CONOPS have to evolve. But the idea of committing the UK's 5th gen effort to countering Bears and Backfires instead of exploiting its capability to operate in defended airspace is an odd one.

You need speed, good range and endurance, large numbers of air-to-air weapons, early warning and ideally tanker support to make a good fist of the air defence role. None of those are strong suits of the QEC air wing. In the NATO context, it has to be said that the USN air wings are much better-suited to it.

I'm ready for the 'party line' response to that, too: that the UK carrier group's availability lets the US do something else with one of theirs. But one of the aims of NATO is famously to 'keep the Americans in' and offering them an off-ramp seems an odd way of going about that. Besides, you only have to follow the news to wonder whether the 'something else' would always be aligned to British interests.

It's not a compelling narrative, IMHO. If there is a SDSR next year (which looks all the more likely now that we'll have a new government as the 5-year point since SDSR15 approaches) then there will be some interesting debate about how to beef up QEC group capabilities so that it can do more under Article V than simply relieve the US of an Atlantic commitment. Where would the cuts fall to make that happen? Or might it be decided that QEC will stay ocean-bound in any Article V plans, leading to announcement of the first UK A-model acquisitions? An interesting year beckons, for sure.

The Role of the Invincible class in the Cold War was as part of the outer screen for a CBG with the Shar able to launch and “hack the shad” as Bear-Ds Tracking the fleet slipped in and out of long range radar cover outside CAP range. Not a role the F-35B will be suitable or able to perform from the centre of its own CBG, and far less capable at the CAP role than the F-14/F-18s if the era.

The threat itself also having been retired and replaced by satellite surveillance. Regardless I cannot see the RN being willing to use the QE as a sacrificial goat to protect a USN carrier.

The primary role of the Invincible class was to operate nine or so ASW Sea Kings for task group ASW in the Atlantic and GIUK gap. The Sea Harrier came later (and the anti Bear role existed because the Bear provided long range targeting for Soviet submarine launched missiles) - and the AEW Sea King after that. I have no idea what the party line is today - but I assume were are still in the business of maritime task groups, and crisis response shipping -and they are major exercises planned such as DEFENDER 2020.

The carrier will not always have to have as many jets aboard as possible. This was one of the reasons for acquiring the B, as the C version would mean constant deck landing training. For some reason people overlook this, like they ignore the manpower needed for cats and traps..

This looks like a tooled up jet to me:

The F135 STOVL propulsion system weighs almost 4,000 lb more than the CTOL version. I would guess that this number includes only the bits for which P&W as prime is responsible, which would not include doors and actuators.

The difference in OEW is less, as Engines correctly points out, but that is due to the omission of the gun and its feed system and an aggressively lightened airframe.

As for the F-35C: It was the last version to close and the wing area and OEW continued to grow through 2006. 35 per cent bigger wing than a Super Hornet, because it lacks an effective high-lift system. I don't think it's a great example of a CV penalty at work.

On the Rafale commonality: I don't have any parts-count numbers, but I do know that Dassault employed and improved CATIA with the aim of getting the best balance between eliminating "scar weight" on the CTOL and maintaining commonality. Some of this involved the idea of "cousin parts" - differing in weight and strength but fitting together in the same way - and the idea of concentrating the difference in the smallest possible number of parts. This was a JSF goal but I think a lot of it went out of the window in the Great Weight Panic.

https://cimg5.ibsrv.net/gimg/pprune....87ca6a61b7.jpg

LO,

Sorry, I think I could helpfully respond here:

The empty weights I quoted were actual 'as weighed' from the 2016 OT&E report. Once again, for clarity, all three variants (that's A, B and C) have 'aggressively lightened airframes'.

Yes, the B and C don't have an internal gun, but the point I was trying to get over (and clearly not doing very well ) is that the B and C both have substantial 'penalty weights' for ship operation. (I suppose I could make the argument that the A model carries a penalty weight for having to have a gun - I believe that it was the only variant for which an internal gun was specified in the System Requirement Document). The B and C also lack the heavy boom refuelling receptacle that the USAF demanded for the A. Apples and oranges and all that....

LO is correct that the C was the last variant to be designed, but I'm not sure that this is relevant to the weight issues. For clarity, the original 'batting order' for the programme was A, then B, then C. Once the weight problem was realised around 2004, the weight reduction effort was focussed first on the B, as that was the variant most severely affected. From then on, the batting order ran B, A, then C. Almost all of the weight saving measures developed for the B were moved over to both the A and the C. What is true is that the C was able to exploit most of the B's weight saving changes earlier in its design cycle than the A, so there was less rework than on the A. One big measure it couldn't adopt, though, were the reduced size tail fins - the C had to keep its big fins for the low speed approach.

Yes, the F-35C does lack the F/A-18's slotted flaps, but that was driven by LO issues and known at the outset when the wing was sized. I have to gently disagree and say that, for my money at least, the F-35C's design is a perfectly valid example of a 'CV penalty'. I had some involvement in some of the CV specific design work and I can confirm that deck ops exacted a significant penalty in weight. The main thing I took away was that the DOD's selection of carrier approach speed (Vpa) as a Key Performance Parameter (KPP) was absolutely on the nail - it was the parameter that drove much of the C's design.

LM used CATIA, not always as well as other companies I worked with, but they got better as time went on. Yes, they wanted to limit the number of differences between variants, but during the weight reduction effort they had to make more compromises than they originally wanted. In some cases, it was found that 'commonality' was imposing severe weight penalties, and variant specific changes were essential. As to 'cousin parts', LM used the idea frequently, and had been for some time - McDonnell Douglas were certainly using them in the 1970s and 80s. As I've posted a number of times, LM made a poor job of the airframe design and, unforgivably for any combat aircraft but especially for a power lift aircraft, failed to keep control of airframe weight. In my view (and just opinion) it cost the programme at least two years and a ton of money.

I hope these posts help people understand that getting the F-35 programme across the line has been a massively difficult undertaking. Yes, one can pillory LM for not doing better. One can also recognise that they (and NG and BAES) have made some towering technical achievements along the way to get the programme to where it is now. And those achievements rest on sheer hard work and brilliance from thousands of dedicated people.

Best regards as ever to my friends at LM and BAES,

Engines

PS: and now I really will go quiet for a bit.

No, please don't do that!

Some of the technical aspects & more so the reasoning behind them make for vey interesting reading.

The second part of Chris Terrill's documentary about HMS Queen Elizabeth and last years WESTLANT 18 deployment is in BBC2 at 2000 GMT tonight. Last week focused a lot on the first F-35B landing and take off, but also mentioned the ASW role of the Merlin HM2.

I believe it is on BBC iPlayer too.

When the replacement for the Invincible class CVS (ASW carrier) was first studied in the nineties, it was apparent that larger carriers were needed. The 20 000 size of the Invincibles was a legacy of their origin as platforms for ASW in the NATO theatre, operating sufficient helicopters for constant dipping (sonar in water). It just so happened they making them just a little larger allowed a Harrier sized aircraft to be operated. This was useful as the Soviet submarines often carried missiles with guidance provided by Bears, so Harrier became Sea Harrier to 'hack the shad'. The addition of an AEW capability post Falklands meant that the jets could be used more effectively than standing constant CAP.

In the nineties, the small size of the CVS limited our ability to carry a meaningful number of jets, both Sea Harrier (primarily air defence) and Harrier GR7/9, plus the ASW and AEW helicopters. Post Cold War, the assumption was made that Cold War type missions such as ASW, fleet defence, protecting sea lines of communication and so on were things of the past, as we opted to fight campaigns in landlocked (or nearly landlocked), so the politicians, and public bought into the carriers = attack only type thinking.

F-35B was the only V/STOL successor to Sea Harrier/Harrier, and was intended to be capable of the full range of missions including Defensive Counter Air and Offensive Counter Air. Even without security and Geopolitical issues with Russia, it should have been clear that after Iraq and Afghanistan, the next conflict would most likely involve an adversary with naval and air capabilities such as submarines or MiGs.

Part of the problem (for the RN) is that no record was kept of why STOVL was the preferred option (cost of equipment, the training burden, manpower, and operating limits for smaller carriers in higher sea states) to inform the politicians, nor were the whole ship aspects of fixed wing flying properly articulated.

And very good it was too!

Peace, Engines...

We seem to be mostly in factual agreement. The interesting thing is that discussing "penalties" or "scar weight" in the A/B/C context depends on which version is considered as the baseline - but thinking about it some more, this may be misleading, since none of the versions is the baseline.

The key to understanding the aerodynamic, structural and propulsion elements of the F-35 design is that no aircraft in history, that I can think of, has had such diverse and competing requirements imposed on it, along with a battery of non-negotiable constraints.

t was much more than what the late George Muellner described as "three versions differing only in how they took off and landed". CV requirements meant (eventually) quad tails and either a large wing, or the ability to accommodate two wing sizes. STOVL mandated a single large engine, located close to the CG, along with minimal OEW. Compatibility with different ships imposed limits on span and length. LO demanded large internal volume, translating into a rather broad body and an unusual relationship of net to gross wing area, and was unforgiving regarding changes to the mold line - all versions had to have the same wing sweep.

It would all have been hard enough, even without the USAF's willingness to die on the barricades to protect sustained 9g. For what it's worth, I don't think any of the designs submitted in 1996 would have done any better than the F-35. The engineers did their best, but there was no elegant solution to the problem enshrined in the JORD.

Thanks for your reply Engines. :D

Much enjoyed, although rather sad to see the tribute at the end in memory of Nimali Amaratunga-Brearley, the young civilian engineer seen earlier in the programme testing the flight deck coating.

Jack