Author Topic: Stealth comes at a price for F-35 fighter  (Read 463 times)

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Stealth comes at a price for F-35 fighter
« on: November 06, 2013, 03:41:13 AM »
Big defence projects can be a risky business for the main contractor and its suppliers and nerve-wracking for the customers. A classic example of the difficulties and challenges is the F-35 joint-strike fighter, a 50-year, $1.5tn programme that has flown into turbulence caused by excessive complexity and rising costs.

Originally presented as a cost-effective means of replacing diverse fleets with a single type, it now threatens to reduce customer fighter forces to numerically ineffective levels.

Built by Lockheed Martin of the US with the UK’s BAE Systems as a prime contractor, the F-35 was created to fulfil every task – attacking well-defended targets, supporting ground troops and matching opposing jets in air to air combat.

But the aircraft has become a victim of its own broad remit. Its radical stealth characteristics play well with politicians and the public who relish the idea of an “invisible” jet. However, stealth comes at a price way beyond the expense it adds to design and construction.

A stealthy fighter is slower and less manoeuvrable than conventional rivals, and needs to conceal weapons in an internal bay to maintain a sleek, radar-evading profile. Contrary to popular opinion, a stealth aircraft is not invisible, but is much harder to detect on existing radars, thus giving the pilot more time to attack a well-defended target.

Energetic radar development in both Russia and China may see this advantage watered down by the 2020s, as ever more sophisticated radars enter the export market.

The internal weapons carriage of the F-35 is limited, meaning that for many of the missions flown by Nato jets over Libya or Afghanistan the aircraft would need to carry bombs and missiles on external pylons. Because these weapons and their pylons protrude under the wing they eliminate the vastly expensive stealth aspect of the airframe, while the manoeuvrability penalties of stealth design remain to hamper the jet’s combat agility.

As stealth means deleting any radar-reflecting outlines, the F-35 cockpit canopy is set low, almost flush with the fuselage. Pilots on test squadrons in the US have noted how this eliminates the fine view from raised cockpits on established fighter designs such as the F-16. Despite high-tech sensors in the F-35, clear vision is still highly valued by military air crew and is yet another sacrifice made to stealth.

The F-35 emerged from plans to kit out the US Navy, Air Force and Marine Corps with a single basic type, adapted for each service’s needs. Their widely varying requirements would be catered for by building three versions, with a short take-off and vertical landing (STOVL) model to replace the Harrier jets flown by the Marines.

The genius of the British-designed Harrier lies in its Rolls-Royce engine, which directs jet thrust through four nozzles that can be rotated for take-off, level flight and landing. The same engine parts that allow the Harrier to hover are also used in conventional flight, so no weight penalty is incurred by the STOVL capability.

By contrast the STOVL F-35 dispenses with this innovation in favour of a separate lift fan embedded behind the pilot’s cockpit. This takes thrust from the main engine and directs it downwards for slow and vertical landings on aircraft carriers. The lift fan has no other purpose than for edging into a small landing zone, but adds considerably to the aircraft’s weight and fuel burn in flight.

To make matters worse, the lift fan also eats into fuselage space, reducing the size of the internal weapons bay. So the STOVL version, on order for the UK’s RAF and Royal Navy as well as the Marines, will be able to sport only a pair of bombs and two self-defence missiles unless it resorts to stealth-busting underwing weapon pylons. The fighter will be deployed on the UK’s two new aircraft carriers, the cost for which was revealed in early November to have risen to £6.2bn. 

Squeezing stealth and other leading-edge digital capabilities into one airframe has pushed the F-35’s costs up and killed off the notion of an affordable jet for all-comers. The US still has a nominal 2,443 F-35s on order. Whether this number will survive US budget restraints is doubtful. Economic pressures elsewhere have seen orders trimmed back amid mounting criticism.

A Dutch order for 85 F-35s has been slashed to just 37 aircraft costing €4.5bn. How these are supposed to replace an existing force of 68 F-16s plus 20 spares is anybody’s guess. This relentless downward curve in the size of Nato fighter fleets is worrying planners tasked with deploying jets to crisis zones.

Canada has put a planned purchase on hold, while it considers more cost-effective alternatives. And with each reduction in orders, the economics of the entire programme come under question. A huge order book is essential to keep the unit cost down. Some Washington critics have spoken of a “death spiral”, whereby each cut in orders adds to the unit price and ultimately brings the whole programme crashing to earth.

Lockheed Martin says that technical problems, a protracted development schedule and soaring costs are all now under control. And F-35 design and assembly is spread across US industry, creating a significant political momentum. Douglas Barrie, senior analyst at The International Institute for Strategic Studies, thinks the death spiral outcome is unlikely, but admits that significant US cutbacks could change the entire picture.

The US Navy is not as committed to the F-35 as it might be, with existing conventional jets still in production and an advanced, unmanned bomber under testing. A promised work share of more than 10 per cent for the UK, with BAE Systems building rear fuselages, means that British participation is guaranteed whatever the jet’s handicaps.

“Retrospectively, you’d not try to design one aircraft to do so many different jobs,” says Mr Barrie. The programme will probably survive because of economic rather than military logic. But it is clear that we will not see an attempt to shoehorn such radically different requirements into one pricey airframe again.


  • Guest
Re: Stealth comes at a price for F-35 fighter
« Reply #1 on: November 06, 2013, 03:42:26 AM »
But it is worth it.

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