Fixing the F-35B

Lockheed Martin is building three F-35 variants: one each for the US Marines, the Navy and the Air Force.
Date:5 May 2013 Tags:, , ,

The F-35B Lightning II is the US Marine Corps’ newest warplane, a R1,4 billion stealth aircraft with powerful weapons, ground-breaking electronics and the ability to take off from and land vertically on carrier decks – and it’s having a painful birth, according to a Pentagon analysis released in late 2012.

Lockheed Martin and the Pentagon are developing, testing and producing the aircraft simultaneously – leading to some surprising problems that are revealing themselves during flight tests. – Joe Pappalardo

1.     Nagging nuisance warnings

The friction of air seeping into the guts of an aircraft leads to overheating. But the F-35B’s sensors are triggering faulty cockpit alarms at temperatures more than 39 degrees Celsius lower than intended. New detectors are being installed.

2.     Weighed-down weapons doors

The doors of the internal weapons bay on the F-35B* bear too much of the 2 360 kg munition load, leading to testing delays. The warplane can fly with weapons mounted on its wings, but exposed missiles and bombs compromise the aircraft’s stealth profile.

3.     Hot horizontal tails

The tails of all F-35 variants are getting too hot during high-speed flight, scorching the coatings that help them defeat radar. Last September, the F-35 programme’s engineers modified the tails, but the fix delaminated and burned away during flight.

4.     Performance anxieties

The F-35B may have battlefield shortcomings. The Pentagon has eased its requirement for the craft’s tight turns, trimming its sustained g’s from 5 to 4,5. Also, testers found excess oxygen in the fuel tanks, increasing the risk of explosion if struck by lightning. A redesign is under way.

5.     Broken nozzle covers

When the F-35B hovers, exhaust is routed through ports in its wings to maintain stability, but the doors covering these nozzles can snap off during flight. Engineers devised an interim fix to close the doors more tightly. Planes delivered after 2014 will have a full repair.

Glossary:

Fueldraulics: The F-35B’s lift-fan engine uses highly pressurised fuel, rather than hydraulic fluid, to move actuators in the exhaust port. Engineers invented a new word, fueldraulics, to describe the system. The F-35B’s original design included shut-off valves that would prevent fires if the F-35B were damaged by enemy weapons, but engineers removed the safety system during a 2008 weight-reduction effort. The result, according to the 2012 Pentagon analysis, is “a 25 per cent increase in aircraft vulnerability”.

 

Watch the F-35B complete ship suitability testing here.