By Nicholas Drummond

This article is a slight departure from usual Land Power topics, but discussions about RAF aircraft remain relevant to this site’s over-arching agenda, not least because RAF aircraft perform a vital role in providing close air support for UK ground forces.

F-35B STOVL variant of the Joint Strike Fighter (Image:: UK Ministry of Defence)


01 – Introduction
02 – The importance of the Royal Navy and Carrier Strike
03 – The F35 Joint Strike Fighter Program
04 – The need to replace the Tornado GR4
05 – The case for the F-35A
06 – What about Tempest?
07 – Summary

01 – Introduction

 The Lockheed-Martin F-35 Joint Strike Fighter has polarised opinion like no other aircraft.

For diehard critics, the F-35 program is a trillion dollar disaster. It has taken more than 20 years to bring the JSF into service and it has yet to fully meet all operational requirements. The development process has been plagued with technical issues that have delayed its IOC while increasing purchase and sustainment costs. Many of the F-35’s problems are blamed on a “concurrency” strategy, whereby manufacturing commenced before the final production specification was nailed-down. This means that early production aircraft need to be re-manufactured to conform with the latest build standard to be fully capable. Regardless of the aircraft’s technical performance, detractors insist that the acquisition process has been less than ideal.

For advocates, the F-35 is the greatest engineering achievement of this generation. It isn’t just a new aircraft, or a new way of building aircraft, but a fundamentally evolved approach to air combat. Rather than just being a single airframe, it is a family of three different role-specific platforms, each with unique strengths that make it excel across particular mission types. The Northrop-Grumman AN/APG-81 AESA radar gives the F-35 an unmatched ability to locate targets. With this and other on-board sensors linked to an airborne battle management system, several aircraft can be networked together. This enables a group of F-35s to see and engage enemy targets long before they enter visual range. Forming an airborne screen, they can dominate the air across a broad front.[1] Among those who now operate the F-35, there is a strong belief that its next generation capabilities will preserve the NATO Alliance’s technical and tactical advantage versus Russian and Chinese aircraft for decades to come.

F-35 Production line at Fort Worth, Texas (Image: Lockheed-Martin)

Inevitably, such capabilities come at great cost. The US Department of Defense realised that the JSF would need substantial and sustained investment to ensure it met program goals. However, it’s not clear, whether anyone ever thought that the F-35 would be as expensive as it has become. According to the Pentagon, total F-35 acquisition costs are expected to be $406.5 billion over its lifetime, while total operational and maintenance costs are estimated to be $1.1 trillion. This does indeed make it the most expensive aircraft program in history.[2]

However, as production has ramped-up and more customers have decided to purchase the F-35, prices have dropped and are expected to be reduced further. Current costs per aircraft are:[3]

F-35A: $89.2 million
F-35B: $115.5 million
F-35C: $107.7 million

(For comparison, it is worth noting that the Eurofighter Typhoon and SAAB JAS39 Gripen both cost in the region of $90-$110 million each.)

While the Pentagon may not have expected the F-35 costs to be so stratospheric, the program was just too big and too important to fail. Was it unnecessarily ambitious, complex, and risky? Possibly. The F-35’s on-board computer, for example, has more than 8 million lines of software code – more than four times that of another 5th generation fighter, the F-22 Raptor.[4] But the F-35 needed to set the bar high if it was to deliver the step-change in capability needed versus legacy aircraft.

So, the trillion dollar question is: does the F-35 live up to expectations?

Concurrency has actually been a successful manufacturing strategy. It ensured that aircraft were quickly made available to customers so that testing and evaluation could begin sooner. With a larger test fleet flying, feedback was easier to collate and analyse, meaning that issues were corrected sooner, and a higher base performance standard was ensured. According to Lockheed-Martin, the cost of retrofitting new components to earlier F-35 examples will be a fraction of the total procurement cost.

In 2017, The US Air Force ran its annual Red Flag exercise at Nellis Air Force Base, Nevada. This is a week-long shakedown that tests aircrafts and pilots to the limit. Participants are divided into Blue and Red teams and conduct air missions against each other. According to US publication Aviation Week, a squadron of 13 F-35As flew 110 sorties to achieve a kill ratio of 15:1. The F-35 succeeded not only in long-range encounters, but also in close-range dog-fighting versus the F-16, F/A-18 and other 4th Generation aircraft. The F-35A’s success was a stunning vindication of the JSF program. Even so, further refinements, such as the Block 4 software upgrade, are expected to improve performance further.

Meanwhile, in separate tests, the F-35B, the Short-Take-Off-and Vertical Landing (STOVL) variant that the UK has ordered has performed well, not only in US Marine Corps testing, but also in recent UK sea trials aboard HMS Queen Elizabeth, during October and November 2018.

F-35Bs flown from UK aircraft carriers will be a cornerstone of UK power projection for the next half-century. Given limited resources for UK Defence, the F-35B program has come under intense scrutiny. It has already been cancelled once. After the 2010 SDSR, the decision to buy the F-35B was modified in favour of the F-35C Carrier Version, which, like the F-35A takes-off and lands conventionally. However, the plan to fit an Electromagnetic Aircraft Launch System (EMALS) to the UK carriers would have added around £500 million to the cost of each ship, so the decision was reversed. Since EMALS technology for new US carriers has yet to be perfected, it was a wise decision. Moreover, the STOVL capabilities give the F-35B much greater flexibility when operating from forward land bases, as RAF aircraft will.

Fighter jets join forces with British aircraft carrier to make history
An F-35B takes off from HMS Queen Elizabeth using the ships ski jump. (Image: Royal Navy by Kyle Heller)

Another casualty of the 2010 SDSR was the early retirement of the Harrier fleet. This was a shocking loss of capability. When the UK’s F-35B fleet declares Initial Operational Capability (IOC) by the end of this year, carrier strike will have been gapped for almost a decade. For these reasons, the F-35B is  a sacred cow. It certainly represents an essential asset that the Royal Navy is keen to protect and promote.

Given this backdrop, recent suggestions that the RAF now wants to acquire the conventional take-off F-35A Joint Strike Fighter variant, were not well received. The Navy believes that any F-35A purchase could potentially compromise the total F-35B fleet size for the carriers. This un-leashed a barrage of negative criticism aimed squarely at the RAF. Therefore, the aim of this article is to consider the case for a mixed buy of F-35As and F-35Bs.

02 – The importance of the Royal Navy and Carrier Strike

Before any discussion of the A versus the B takes place, it may be worth stating a few underlying truths relevant to this topic.

First, the UK is a maritime nation that depends on seapower to ensure its security and the continuity of supply of vital resources. This makes the Royal Navy the most important of our three services. Ensuring that the Royal Navy is resourced to protect UK interests at home and abroad remains paramount. No one, least of all the RAF, seeks to compromise the Navy’s ability to perform its essential roles. To do so would be the military equivalent of fratricide.

F-35B on board HMS Queen Elizabeth (Image: Royal Navy / UK Ministry of Defence)

While destroyers, frigates and attack submarines are vital for North Atlantic security, aircraft carriers allow us to project power further afield. This is important, because Britain has a long history of going out to meet emerging threats at distance, before they turn-up fully-formed on our doorstep. Aircraft carriers are mobile sovereign airfields that can go anywhere in the world to conduct combat operations. The way in which the USA has maintained a fleet of large nuclear-powered carriers has been an undoubted success factor in projecting US power over the last half-century. Getting permission for conventional combat aircraft to conduct air attacks from a foreign state’s airfields can be difficult, time-consuming and costly. Sometimes, the mere presence of an aircraft carrier can have a deterrent effect. We used to call this gunboat diplomacy. Whatever we call it today, it remains relevant.

The UK’s previous aircraft carriers, the Invincible Class, were also acquired at a difficult moment financially, just after the oil price crisis of the early 1970s, so were similarly criticised as being unnecessary and unaffordable. The Navy described them as through-deck cruisers to convince HM Treasury that they weren’t real aircraft carriers and therefore financially justifiable. Once HMS Invincible and her sister ships entered service, it soon became apparent that even small carriers were still essential commodities. We would never have been able to retake the Falklands without such ships. What we learned from the Invincible Class is that two larger carriers are better than three smaller ones, which is why HMS Queen Elizabeth is 65,000 tonnes not 30,000 tonnes. Larger ships that carry more aircraft can fly a higher number of sorties within a 24-hour period. When the aim of air power is to destroy key targets as quickly as possible, sortie rates matter. While the cost of £3.5 billion per Queen Elizabeth carrier[5] makes it the most expensive ship acquired by the Royal Navy, it compares favourably to the USS Gerald Ford Class of nuclear-powered super carriers which cost $14 billion per ship.

The aircraft that fly from UK carriers are obviously a vital part of the overall capability equation.  The Harrier jump jet, which was the first aircraft of its kind, proved the viability of the Short-Take-Off and Vertical Landing (STOVL) concept for carrier-borne operations. Providing 40 years of stalwart service, it was only natural that a similar type of aircraft should be chosen to replace it. Given that the UK could not afford to develop a Harrier replacement independently, we were fortunate that the US Marine Corps’ parallel success with a US version, the AV-8B, led to a STOVL variant being proposed as part of the F-35 Joint Strike Fighter program. This is how the UK became the only Tier 1 partner for the JSF, with Rolls-Royce using its expertise to develop the F-35B’s lift fan technology.

03 – The F35 Joint Strike Fighter Program

The F-35 was primarily conceived to replace the USAF’s F-16 multi-role fighter, a hugely successful aircraft with more than 4,500 built and sold to 27 different air forces. In order to be a credible successor, it was decided to develop three separate F-35 versions:

F-35A. Conventional Take-off and Landing (CTOL) to replace the F-16 Falcon

F-35B. Short Take-Off and Vertical Landing (STOVL) to replace the AV-8B

F-35C. Carrier Version (CV) to replace the F/A-18 Super Hornet

Ultimately, the JSF programme was not about developing three versions of a single aircraft, but three separate aircraft. This is what has most contributed to its complexity, cost and elongated development timeline.

F-35 needed to be supersonic.

F-35 needed to be stealthy – which required an internal weapons bay.

F-35 needed to provide a networked capability allowing aircraft to share data so that targets could be prioritised and allocated across several aircraft.

F-35 needed to automate as many processes as possible so that the pilot could focus on the fighting the air battle rather than worrying about human/ machine interfaces.

F-35 needed to encompass a completely new way of fighting in the air: engaging enemy targets at distance before they can detect it. This was the second critical factor that has complicated the development process.

To be fair, getting so many leading-edge technologies to work in a single combat aircraft would have been a massive undertaking. To do so in three different variants was a Herculean task and more challenging than anyone could have imagined.

The F-35A

The F-35A was always the most important version of the JSF, because it will be bought in the largest numbers and used as both an air defence fighter and strike aircraft. The development process had to ensure that the need for a STOVL variant didn’t fundamentally compromise the F-35A’s dog-fighting ability. This meant that the F-35A needed to be able to pull at least 9 Gs, which it does.

The F-35B

The F-35B is close in overall dimensions to the F-35A, but loses some internal volume in the forward fuselage to accommodate a forward lift fan. The rear nozzle pivots from a horizontal to a downwards-pointing position to provide vertical lift. It is an extremely innovative solution, but the lift fan adds parasitic weight when in forward flight. Increased weight compromises agility, but the F-35B gives away very little relative to the other versions. It can still pull 7 Gs. The key concern with the F-35B is that the lift fan reduces internal fuel capacity decreasing range and endurance.

(With the Harrier, the UK pioneered an angled ski jump for carrier take-offs. This allows a STOVL aircraft to get airborne more easily when carrying a full load of ordnance. The QE Class carriers will also have this feature.)

The F-35C

The F-35C is conceptually similar to the F-35A except that it has larger wings (which generate increased lift for carrier take-offs and landings). The wings fold to aid hangar stowage and it has a reinforced undercarriage and tail hook for the arrestor wire to snag on landing. It has a slightly higher fuel capacity for increased range.

F-35 specifications
JSF comparison data (Source: Lockheed-Martin)

While the F-35B has a slightly lesser performance than the F-35A and F-35C, versus the Harrier II (GR5/ GR7 / GR9), the F-35B is in a different league.  Just to emphasise this point for F-35B doubters, it offers the following advantages relative to the Harrier II:[6]

  • Stealth capability
  • Supersonic performance of Mach 1.6 (1,975 kph) versus Mach 0.9 (1,065 kph)
  • Greater internal fuel capacity of 6,125 kg versus 3,400 kg
  • Weapons payload of 6,800 kg versus 4,200 kg
  • Un-refuelled range of 833 km versus 556 km

The UK previously had 60-80 Harrier II aircraft and a total fleet size of 143 over its lifecycle.[7] Under current plans, we will acquire 138 F-35Bs over the lifetime of the airframe, but this is not a definitive force size.[8] While the Navy will have two carriers, only one is expected to be used at a time. According to Fleet Air Arm sources, each carrier will routinely deploy with 12-15 aircraft on-board. This will increase to 24 for operations and they have a surge capacity of 36 aircraft. In addition to this, there will be a training squadron, so the Joint F-35 force requires a minimum of five squadrons, or 60-72 aircraft. An ideal number might include two further squadrons, or 96 aircraft in total, enabling the RAF to support for ground force from forward bases as the Harrier did before.

A UK F-35 pilot who provided input to this article suggests that any comparison of F-35B with Harrier or Tornado is futile. F35B is to Harrier what Typhoon is to the Sepecat Jaguar. Any F35 is an extremely capable dog-fighter and the flight control software allows it to perform some very impressive manoeuvres. Against an F-16 it can hold its own and against an F-18 it’s superior. The important thing to remember is that off- bore sight cueing of highly agile missiles levels the playing field, since the same helmet is used to do this across all F35 variants. It means you no longer need to get behind an enemy to shoot him down. If you can turn reasonably hard and move your head to look directly at the aircraft, you can lock with the missile (seeker is slaved to your head pointing angle) and shoot. While the USAF demanded 9G out of a dogmatic adherence to the beloved F16, F35 really doesn’t need it – but has it.

Despite Brexit fears and potentially disadvantageous pound-dollar exchange rates, there has been no suggestion that F-35B numbers will be cut. What can be said definitively is that we will have failed to replace the Harrier and failed to resource carrier strike properly if we acquire less than 60-72 F-35Bs for frontline service.

04 – The need to replace the Tornado GR4

The RAF has 60-72 Tornado long-range strike aircraft. It was developed in the mid-1970s with a total of 992 built and used by the UK, Germany, Italy, and Saudi Arabia. Affectionally called the “Tonka” and highly regarded by its pilots, the Tornado has seen extensive operational use. It was deployed in Iraq during the first Gulf War; Former-Yugoslavia during the Bosnia / Kosovo War; again in Iraq during the Second Gulf War; Afghanistan between 2006 and 2014; Libya during the Civil War; and continues to be used in 2018 in Syria. The Tornado’s operational track record makes it one of the important RAF aircraft to see service during its 100 year history. Despite its success, the Tornado fleet is showing its age and will be retired from March 2019.[9]

The RAF’s Tornado has been in service for 40 of the RAF’s first 100 years, making it one hits most successful aircraft. (Image: RAF / UK Ministry of Defence)

While the F-35B will take-on a variety of Tornado roles, it should be remembered that F-35B is primarily intended to replace the Harrier in a Royal Navy Carrier Strike role. As already noted, as a STOVL aircraft, the F-35B’s lift fan means that it carries dead weight that limits its capacity for fuel and ordnance. No less important, 60-72 F-35Bs cannot replace 60-80 Harriers plus 60-72 Tornados. We need to replace Tornado, but equally we must maintain a critical mass of frontline aircraft so we have resilience in a protracted conflict.

The RAF presently operates a fleet of EF2000 Eurofighter Typhoon fighter aircraft for use in the Air Defence role. It has now upgraded 40 out of the current fleet total of 149 aircraft to the latest Tranche 3A standard, so that Typhoon can perform a secondary strike role.  Although we also have an additional 67 Typhoon Tranche 2 models, when an aircraft is being used in the strike role, it reduces the available fleet size for the air defence role.

Without the 2010 Defence cuts, the RAF would have had the following combat aircraft fleet composition:

60-72 Tornados
149-160 Typhoons
60-80 Harriers*
This adds-up to a total of 269-312 aircraft.

*(We should not forget that when the Harrier was retired early as cost-saving measure, it not only reduced the total combat aircraft fleet by 20%, it also gapped the STOVL capability for 8 years. Neither fact changes the need for additional strike aircraft so that we have a credible total.)

05 – F-35A versus additional Typhoons

It has been suggested that buying additional Typhoon Tranche 3 aircraft could offset the loss of the Tornado. However, at a total cost of £17.6 billion for 160 aircraft, Typhoon is the most expensive combat aircraft procured by the UK to date. Individual Typhoon FGR4s cost approximately £110 million. This makes Typhoon at least as costly as the F-35B, but without a STOVL or stealth capability. A further problem is that Typhoon is a 4th generation aircraft that will be obsolete by 2035, so any additional aircraft purchased now will have a short shelf-life.

F-35A CTOL variant

Alternatively, we could acquire additional F-35Bs, but since these are expensive and are designed for the carrier role, could we be better off using the F-35A? The RAF thinks so.

The F35A has a number of significant advantages compared to be F-35B:

  • Increased range(1,093 km versus 833 km)
  • Increased payload(8,160 kg versus 6,800 kg)
  • Increased G-rating(9.0 versus 7.0)
  • An internal cannon
  • Less weight and increased agility(The F-35A more capable in the air defence role)
  • Lower purchase price(F35A: $89.2 million versus F-35B: $115.5 million)

The F-35A’s longer internal weapons bay allows it to carry up to 6 AMRAAM missiles internally, whereas the F-35B can only carry 4. Although this increased capability has not yet been fielded, the ability to carry a higher quantity of air-to-air missiles will be a worthwhile uplift in capability.  The F-35A can also carry two 2,000 lb GBU-31 JDAMs internally, whereas the F-35B can only carry two 1,000 lb GBU-32 JDAMs.[10] Unfortunately, the UK does not use the GBU-31 JDAM at this time so cannot take advantage of the extra space provided. It is possible that the UK may subsequently acquire other new complex weapons that would benefit from being able to be carried by an aircraft with a larger weapons bay than the F-35B.

The F-35A is a simpler aircraft to maintain than the F-35B.  With some 2,500 F-35As expected to be sold versus 500 F-35Bs, spare parts for the A version will be more widely available and less expensive. Overall support costs are expected to be much lower.

It has been stated, ad nauseam, that maintaining two separate fleets is more expensive than maintaining a single fleet. It is difficult to comment on this since there are no definitive cost comparisons that provide a reliable answer. The question is whether the utility and lower acquisition cost of the F-35A offset potential additional fleet running costs.

F-35A showing the mix of weapons it can carry. (Image: Lockheed-Martin)

Some people view the F-35B as a less capable version of the F-35A. While the F-35B’s STOVL abilities come at a cost, it is much closer in performance to the F-35A than the AV-8B Harrier was to the F-16 Falcon. Irrespective of any comparison with the F-35A, the F-35B offers a very high level of combat utility versus any other 4th generation aircraft. If the performance gain with the F-35A is marginal, is it worth the aggravation of having two fleets? In the final analysis, the two aircraft offer complementary benefits which offer great flexibility overall.

06 – What about Tempest?

Earlier this year at the Farnborough Air Show, British Aerospace presented its Tempest concept. This aims to replace Typhoon with a 6th Generation aircraft that has the following features:[11]

  • Stealth / Low observability
  • Able to perform Air Defence and Strike roles
  • Twin, variable cycle engine (VCE) designed to maximise efficiency at subsonic, transonic and supersonic speeds
  • Mach 2.0+ speed (2,500 kph)
  • Manned and unmanned operation
  • Larger internal weapons bay than F-35A

When Tempest arrives, it means that the UK will only need two combat aircraft types: a single-engined STOVL strike aircraft for the carriers (F-35B) and a twin-engine fighter for air defence and long range strike (Tempest). Tempest will be a true replacement for Tornado as well as for Typhoon.

BAE Systems Tempest Concept (Image: Team Tempest)

Notwithstanding its potential benefits, Tempest presently exists only on paper. Given expected high costs and small production quantities, the UK will need to develop this aircraft in partnership with other countries. Without partners, Tempest will be stillborn. Should Tempest fail, we would consider alternative versions of the same concept. We could join the Franco-German Système de Combat Aérien du Futur (SCAF) program which has similar objectives. The USA is also developing its own 6th generation aircraft, the Next Generation Tactical Aircraft (NG TACAIR).

None of the above aircraft is expected to enter service before 2035-2040. The important thing here is not airframe performance, but timing. A decision concerning the Tempest acquisition strategy will be made by 2020, but a final commitment and investment in Tempest is not expected to be made before 2025. The anticipated date for an initial Operational Capability (IOC) is 2035, but, given the time taken to develop both F-35 and Typhoon, a Tempest timeline of 15 years from drawing board to combat readiness seems extremely aggressive if not unrealistic.

To de-risk Tempest, the UK may need a bridge between Typhoon and Tempest. The F-35A, which is likely to remain in service until 2070, could easily fulfil this requirement.

07 – Summary

Prior to 2010, the UK had a total of around 281 combat aircraft. The Harrier fleet was retired early as a cost-saving measure, not for strategic reasons. In fact, since 2010, the number of threats we face has increased not declined. The loss of the Harrier fleet reduced the RAF’s total combat air fleet to just 221 aircraft: 149 Typhoons, plus 72 Tornados), a net loss of 60 aircraft. It was barely acceptable to reduce frontline strength as a temporary cost-saving measure, but not as new level of permanent capability reduction.

Harrier 3
Harrier GR9 in Afghanistan. (image: RAF / UK Ministry of Defence)

Although the retirement of Tornado will be partially offset by the acquisition of 138 F-35Bs, as a STOVL aircraft, it is primarily intended to replace the Harrier. Although the F-35B can perform some Tornado roles, it lacks the Tornado’s range and payload capacity.

We have converted 40 Eurofighter Typhoons to the perform a Strike role, but this reduces the number of aircraft available for the primary air defence role.[12]

Ideally, the UK needs 96 F-35Bs, 149 Eurofighter plus 72 Tornado replacements, or a total of 319 combat aircraft, with an active fleet of about 280-300 aircraft. Typhoon and F-35B are expensive, so we are unlikely to be able to afford a significant number of additional aircraft of either type.

Tempest should be a flexible and capable aircraft when it arrives. The problem with Tempest is that it’s unlikely to arrive before 2035-2040 and since we have no idea of the final specification,  we cannot predict costs or numbers. Many unknown factors make it a risky proposition.

The F-35A is more capable than the F-35B and less expensive than Typhoon. It is also stealthy and well able to perform a Tornado-type bomb truck role. The F-35A is ready now and won’t be obsolete in 10 years time. F-35A costs are likely to become lower as more nations use, while Typhoon costs are likely to increase as it ages.

For the above reasons, the F-35A seems to be an obvious choice to provide the UK with additional capabilityA decision to acquire F-35A in 2020 with deliveries commencing in 2025, would ensure there was no gap between Typhoon being retired and Tempest entering service, if indeed it comes to fruition.

Whatever we do, we should not buy the F-35A at the expense of the F-35B. We must not compromise F-35B numbers or carrier strike.

Before writing this article, I was fortunate enough to receive direct input on the F-35’s capabilities from pilots who know the aircraft intimately. Within the bounds of what they were allowed to say publicly, they were universal in their praise for the aircraft. They’re excited and energised by the prospect of it entering UK service. Whichever versions we acquire, they are in no doubt that it will provide us with a leading-edge not a bleeding-edge capability for now and the future.

UK F-35Bs fly in formation en route to their new home at RAF Marham.(Image: RAF/ UK Ministry of Defence)



[1]Source: Lockheed-Martin, Northrop Grumman.

[2]Source: US Department of Defense, March2018via Bloomberg

[3]Source: US Department of Defense, September 2018 via Defense News

[4]Source: Lockheed-Martin

[5]Source: Phillip Hammond, UK Minister of Defence, November 2013

[6]Source: BAE Systems

[7]Source: UK Ministry of Defence / RAF

[8]Source: UK Ministry of Defence / RAF

[9]Source: UK Ministry of Defence / RAF

[10]Source: US Air Force Program Brief / Lockheed-Martin (September 2006)

[11]BAE Systems, Farnborough Air Show 2018

[12]Source: UK Ministry of Defence / RAF