In my previous blogs I discussed the early experimental, prototype and operational V/STOL combat jet aircraft such as the Harrier and Harrier II that were developed in the late 1950’s through to the 1980’s. By the 1980’s significant improvements had been made in performance, handling and the weapons load capability of V/STOL combat jets but now stealth technology and advanced avionics, communications and weapons systems are required to survive in the modern battle space. The following is a brief history on the latest generation Short Take Off Vertical Landing (STOVL) Joint Strike Fighter (JSF) that is undergoing rigorous flight testing to enter service with various air fleets around the world later this decade. The JSF has become a controversial, long-delayed and expensive project but it is here and it is happening.
JOINT STRIKE FIGHTER
Today we are seeing a dedicated Short Take Off Vertical Landing (STOVL) combat aircraft enter service in the shape of the Lockheed-Martin F-35B Lighting II Joint Strike Fighter (the F-35A is a conventional take off variant and the F-35C is a naval carrier-borne variant). The F-35 is actually a fifth generation fighter (third generation for vertical lift combat aircraft) with stealth technology and highly advanced avionics, communications and weapons systems. From the outset the F-35B was designed to be a fully multi-role capable, highly maneuverable, combat aircraft with STOVL capability and Mach 1.6 supersonic performance (a recent leaked test pilot report claims this highly maneuverable characteristic may not be the case, as an F-16D is said to have bested an F-35A in January 2015 air combat testing but the US Government and Lockheed Martin replied to the report saying the early production F-35A in question lacked the sophisticated avionics, fused sensor suite and software systems of later F-35’s which would give it the edge over legacy aircraft. Naturally improvements can and will be made).
Being a short take off fighter, the F-35 can carry a full weapons load without performance restrictions and operate from airfields, roads, a variety of ship types and forward bases. Unlike it’s V/STOL predecessors the workload on the pilot to fly and land the fighter is significantly less intensive due to advanced flight control systems (Harrier II aircraft are said to have had a high accident rate especially during take-off and landings). The F-35B is intended as a direct replacement for the McDonnell Douglas AV-8B Harrier II.
The Joint Strike Fighter concept is to combine multiple roles into one fighter, including air combat, ground/sea strike, electronic warfare (jam radar, supress radar and SAM sites, disrupt enemy communications), Intelligence, Surveillance and Reconnaissance (ISR – using sophisticated sensors for data capture. The aircraft core processor can complete 400 billion operations per second!). The aim is to improve operational and cost effectiveness by reducing the different types of specialised aircraft required and to be maintained (despite the fact the F-35 is the most expensive fighter ever produced! This is also the most sophisticated fighter ever produced, so that’s not so surprising and costs will go down as more are produced). The F-35 would go in first and take out air defences to enable other 4th Generation combat aircraft to operate more safely in the combat zone.
The F-35 pilot wears a Helmet Mounted Display (HMD) which projects all essential information such as speed, altitude, target information, warnings, and navigational information on the helmet visor which reduces pilot workload and increases situational awareness. A special camera also provides night vision to the helmet. The fighter features a number of other sophisticated systems including:
- An advanced Active Electronically Scanned Array (AESA) radar which can actively track multiple targets and because it operates on multiple frequencies will reduce enemy interception radar detection and increase radar jamming resistance.
- Fully fused sensor information that can track targets and provide real-time information 360 degrees around the aircraft using the:
- Distributed Aperture System (DAS) which incorporates six infrared cameras around the airframe that stream real-time images directly to the HMD enabling the pilot to effectively “look through” the aircraft and maintain full situational awareness day or night. If the F-35 radar detects something the DAS software will analyse the potential threat and inform the pilot. If there are multiple threats DAS is able to identify and recommend the highest priority target to engage first along with advising whether to use weapons or electronics measure to negate the threat.. This feature is invaluable in a complex, fast moving and dangerous battlefield environment.
- Eight sensor Electro-Optical Targeting System (EOTS) which combines Forward Looking Infrared (FLIR) and Infrared Search and Track (IRST) capability to provide air and ground targeting for precise and timely weapons delivery.
- Network enabled operations with ground, sea and air forces to enhance communications and mission effectiveness i.e. what you see, they can automatically see too (and vice versa).
- Stealth technology designed to penetrate enemy areas without being detected by radar and also detect enemy aircraft first and engage them from a stand off distance. This is achieved through airframe design, advanced stealth technology and materials; and internal weapons bays aid the stealth process).
- Advanced electronic countermeasures to increase aircraft survivability.
X-35B Prototype
The prototype Lockheed-Martin X-35B test flight program was very brief and highly successful, lasting from 23 June 23rd, 2001 to August 6th, 2001. The X-35B prototype was the first aircraft in history to achieve a short takeoff, along with a level supersonic dash and vertical landing in a single flight. Today the prototype along with its vertical lift engine is displayed at the Smithsonian Steven F. Udvar-Hazy Center in Chantilly, Virginia. This aircraft is actually the first X-35 ever built and was originally designated X-35A until it was modified with the fitting of the vertical lift engine for STOVL testing.
The X-35 prototype beat a competitor for the Joint Strike Fighter program. Boeing were unsuccessful in their bid with the X-32 experimental demonstrator aircraft. The X-32 featured a large one piece delta wing and for the STOVL version they designed the X-32 to have vectorable nozzles attached to the main engine for vertical thrust. It was a rather stocky looking design and unfortunately the STOVL engine required a large chin air intake (goodbye stealth – mitigation strategies included the concept of variable baffles designed to block incoming radar detecting the engine compressor blades). There was an X-32A navy/conventional take-off demonstrator which first flew on September 18th, 2000 and an X-32B STOVL demonstrator that first flew in March 2001. The demonstrator could not perform STOVL and supersonic flight without being reconfigured on the ground (something the X-35 could do without any changes) so some parts had to be removed to demonstrate STOVL (they advised that this would be rectified later if successful in winning the program). Flight testing ceased in July 2001 and I start to get the picture why on October 26th, 2001 the US Department of Defence chose to continue only with the X-35.
F-35 Lightning II
On July 7th, 2006 the production model of the X-35 prototypes officially became the F-35 Lightning II with 3 variants: F-35A Conventional Take Off and Landing (CTOL), the F-35B STOVL and the F-35C carrier variant which has larger wings than the others. The F-35A maiden flight was conducted on December 15th, 2006 and the first was delivered to the USAF in 2008. The first flight of the F-35B was on June 11th, 2008 and it was not until June 7th, 2010 that the maiden flight of the US Navy F-35C variant was conducted.
The F-35B is fitted with an innovative Pratt & Whitney F135-PW-600 afterburning turbofan engine that incorporates a forward placed Rolls-Royce patented shaft-driven LiftFan® propulsion system for VTOL and the main engine nozzle can swivel 90 degrees to provide vertical and horizontal thrust. This version of the F-35 has a lower fuel capacity due to the size and unique layout of the engine.
United States Marine Corps
The USMC has been testing their first series of F-35B aircraft since 2008. The first operational squadron, Marine Fighter Attack Squadron 121 “Green Knights” (VMFA-121) is based at MCAS Yuma in Arizona with more to become operational by December 2015. Eventually 5 F-35B squadrons with 16 aircraft each and an operational test and evaluation squadron with 8 aircraft will operate from MCAS Yuma. Exciting times lay ahead for the USMC who will receive approximately 340 F-35B fighters in the next few years to replace the McDonnell Douglas AV-8B Harrier II and F/A-18 Hornet’s currently in service.
It was at MCAS Yuma where I had the privilege to see an F-35B put on a spirited demonstration at the 2015 Yuma Airshow. The display included showing the very impressive STOVL capability (one very short take off indeed!), vertical hovering, some relatively high-speed passes and a glimpse of that amazing Pratt & Whitney F135-PW-600 afterburning turbofan engine in use.
RAF and Royal Navy Joint Service
The Royal Air Force and Royal Navy plan to jointly operate 138 Lockheed Martin F-35B Lightning II aircraft and the first of these are already conducting flight testing in the United States with RAF Number 17 Squadron at Edwards AFB in California. In addition to land based operations, the F-35B will form the air fleet for the two new Queen Elizabeth class aircraft carriers being built for the Royal Navy (HMS Queen Elizabeth is to be commissioned in 2017 and HMS Prince of Wales will follow in 2020). Royal Navy 809 Naval Air Squadron (NAS) has been resurrected as the first Navy squadron to fly the Joint Strike Fighter in the UK. The first operational RAF squadron will be the famed Number 617 “Dambusters” Squadron. Given this is a joint service, Royal Navy and RAF pilots will fly in the squadrons of both services.
Italian Air Force & Italian Navy
is scheduled to receive 30 F-35B STOVL (15 Air Force and 15 Navy) variants of the Joint Strike Fighter to replace numerous legacy fighters in Air Force and Navy service including the McDonnell Douglas AV-8B Plus Harrier II aircraft operated by the Italian Navy. The Air Force will also operate 60 F-35A CTOL variants. Italian aviation companies are already producing components for the F-35’s being manufactured for all nations.
The Future of the F-35B
The success of the F-35B Lightning II aircraft is yet to be proven but for now, despite the controversy surrounding delays, technical issues and high costs, it is starting to look and sound very good. The test flights and production of these highly advanced aircraft continues.
The F-35 cost is expected to reduce as more are produced and Lockheed Martin in conjunction with the United States military continue to work on methods to reduce production costs. Lockheed Martin state: “Since we built the first F-35, production costs have dropped 55 percent.”
From the Lockheed Martin F-35 Fast Facts Cost web page:
The most recently contracted unit costs for Low Rate Initial Production lot 7 (not including the engine) are:
- F-35A: $98 million
- F-35B: $104 million
- F-35C: $116 million
An F-35A purchased in 2018 and delivered in 2020 will be $85 million, which is the equivalent of $75 million in today’s dollars.
Along with the USMC, RAF, Royal Navy and Italy, no doubt other countries including Spain who also operate the AV-8B Plus and Australia who are currently putting into service amphibious assault ships will consider the type. The F-35 is an all for nothing deal and they have to make it work!
Future Chinese STOVL?
It may not be too long before China enters the STOVL combat aircraft market. In March 2015 the Aviation Industry Corporation of China announced that its subsidiaries will be working on the development of a STOVL aircraft engine for the proposed production of a Chinese STOVL fighter to operate from future People’s Liberation Army Navy (PLAN) amphibious assault ships and their current CNS Liaoning aircraft carrier. It will be interesting to see what they come up with but given the operational similarities, I suspect it may be a development of the fifth generation, stealthy Shenyang J-31 prototype which made its first flight on October 31st, 2012 and is expected to enter the Chinese Peoples Liberation Army Air Force by 2019. The J-31 is very similar in appearance to the F-35A CTOL variant (I wonder where they go that design concept from?), except it has twin engines, which some say the F-35 should have had (time will tell).
Exciting times lay ahead for STOVL technology. I look forward to seeing what happens!
References:
Smithsonian National Air and Space Museum
