Making the Most of The F35 B

F35B Cutaway

One of the fundamental changes in SDSR 2010 was to select the F35C over the F35B. The rational for this was that the F35C could also replace the Tornado and cover the RAF’s Future Offensive Air System requirement as well as the Joint Combat Aircraft requirement designed to replace the Harrier. However once it became clear that the cost of converting the aircraft carriers would be in the £ 5 billion pound range the decision was taken to revert back to the B model. However despite the decision to revert back to the B model no decision was taken to replace the Tornado with something else. The F35B will now have to serve as both a Harrier replacement and a Tornado replacement.

On June 14, 2012, F-35B Joint Strike Fighter test aircraft BF-2 completed the first test flight for the short takeoff and vertical landing variant with an asymmetric weapons load. BF-2 flew with an AIM-9X Sidewinder inert missile on the starboard pylon, a centerline 25 mm gun pod, and a GBU-32 and AIM-120 in the starboard internal weapon bay.
On June 14, 2012, F-35B Joint Strike Fighter test aircraft BF-2 completed the first test flight for the short takeoff and vertical landing variant with an asymmetric weapons load. BF-2 flew with an AIM-9X Sidewinder inert missile on the starboard pylon, a centerline 25 mm gun pod, and a GBU-32 and AIM-120 in the starboard internal weapon bay.

Having F35B as a replacement for the Harrier will give us capabilities light years ahead of what we had. Despite the criticisms of the B model in comparison to the Harrier it is a major capability improvement. However as a replacement for the Tornado the F35B does have limitations. I believe there are some relatively simple fixes that the UK can use to overcome the limitations of the B model so that it can serve as an effective replacement for the Tornado.


The main criticism levelled against the F35B is its limited range on internal fuel. Most publicly available sources put the F35B’s range on internal fuel at around 900 nautical miles while the F35A has a range of some 1200 nmi and the F35C has a range of 1400 nmi. These range figures compare quite favourably with aircraft like the Tornado simply on internal fuel. However a Tornado would rarely fly a mission on internal fuel alone. Generally it would also use external drop tanks.

The issue for a stealth aircraft is that if it uses drop tanks it will compromise is stealth capability meaning there was little point in investing billions of pounds in an aircraft that can offer little improvement on the previous generation.

However there is a relatively simple get around for this problem. The F22 uses a drop tank system that actually detaches not just the drop tank itself but the wing pylon it is mounted on. This means that once the tank is dropped the aircraft regains its clean stealthy form. It can then conduct the rest of it mission on its internal fuel.  According to Lockheed Martin the F35B’s internal fuel capacity is 13,100 lb. The inclusion of two under wing fuel tanks would increase this by an additional 8,000 lb, around a 60% increase.

Obviously the extra weight and drag from the tanks would mean that a 60% increase in fuel would not translate into a 60% increase in range but it should give a very substantial boost none the less.

Obviously dropping expensive stealthy fuel tanks would not be ideal but we should ask the question, on how many occasions will the F35 need to be in a stealthy configuration? probably only for the first few days of an air campaign while the enemies air defences are destroyed.

The Israeli’s are already reported to be working on such a design so there may well be an off the shelf solution soon. If not then it is probably not beyond the ability of the United Kingdom to develop such a solution on its own.

Bomb Bays

The other major criticism levelled against the F35B is that it has smaller internal bomb bays than the other two models. It will be unable to carry internally a 2000lb bomb such as the Paveway III.

However it’s worth noting that due to the size of the Paveway III kit that no version of the F35 can carry a Paveway III internally. Nor for that fact can the F22.

The other question to ask is how useful is the Paveway III in modern combat. As far as I can see in operations over Libya we did not drop a single Paveway III bomb. Paveway III’s main use would be for attacking bunkers and other hard and buried targets. With the development of weapons such as Storm Shadow the need for such a weapon seems to have been reduced substantially. All bombs dropped by the RAF over Libya were either Paveway II or Paveway IV in the 500lb range. With greater accuracy of modern munitions and less tolerance for collateral damage the smaller bombs seem to have become much more useful.

The F35B will be limited to only the Paveway II or IV for internal carriage. However it can carry the 1000lb JDAM internally. If there is a need for a bigger bomb then we could go to the extraordinary length of buying 1000 lb JDAM’s. This bomb will already be integrated on the base line F35B so the cost of procuring it will be very small.

This might seem a bit puny to some but it’s worth noting that the F22 can only carry the 1000lb JDAM internally and it has to sacrifice its AMRAAM missiles in its large bomb bay to do so. Our F35B’s could carry two JDAMS as well as 2 Meteors internally and 2 ASRAAM’s on the stealthy wing pylons. Not a bad load in my estimation. So the question over the B model vs. the C model in UK service comes down to, what can you do with a 2000lb JDAM that you can’t do with a 1000lb JDAM?

In addition with modern air defences I see little if any chance that any air force will be flying deep penetration missions like the F117 did over Baghdad in 1991 no matter how stealthy their aircraft are. Stand-off weapons will be used for such missions while the enemy’s air defence capability is picked apart.

Suppression of Enemy Air Defence

In my mind the major use for low observable aircraft will be clearing out an enemy’s air defence in the opening days of any campaign. The RAF has withdrawn the ALARM missile from the Tornado and has no plans to integrate it on the Typhoon or F35. Many critics see this as the RAF getting out of the Suppression of Enemy Air Defence business altogether. The F35B could certainly not carry the ALARM missile internally but given its size I don’t think any version could.

However the RAF has commissioned the SPEAR 3 missile from MBDA specifically for the F35B. It will be able to carry eight of these missiles internally as well as two meteor missiles and two external ASRAAM’s.

Beam riding missiles like HARM and ALARM are an out-dated concept. What is far more useful are weapons able to recognise targets that can be targeted by the aircraft’s Synthetic Aperture Radar from long range.

Also weapons that can be re-programmed in flight to deal with evolving threats. Indeed the MBDA video for the SPEAR missile shows exactly how the RAF will use the F35B to attack an air defence system. So in comparison to the Tornado in the SEAD role we have a stealthy F35B equipped with up to 8 internally carried SPEAR missiles and a radar capable of not only imaging and targeting threats but also of conducting electronic attack vs. a Tornado with two Alarm missiles and a Sky Shadow ECM pod trying to find a missile battery by waiting until it has locked its radar on to the Tornado.

The F35B certainly seems like a major capability improvement over Tornado in this respect.


While the F35B does have its limitations there are some relatively simple fixes which can allow it to be every bit as capable as the Tornado.

The inability to carry the Paveway III bomb is a limitation but then this is a limitation shared by all present Fifth Generation aircraft. If such weapons are needed then it’s a job for the B2 and looking at recent operations it’s a niche capability that will be used rarely at best.

It’s also important to note that the F35B does come with some major advantages. Savings in commonality between the FAA and RAF are substantial and the aircraft’s ability to take off from ships at sea as well as short air strips gives it a level of operational flexibility un-matched by any other aircraft in the world today.

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