Vid The F-35B Lightning II, world's first supersonic stealth jumpjet and successor to the famous Harrier, has carried out its first "short" landing. Test pilots are currently making slower and slower flights with the aircraft, progressing gradually towards hovering vertical landings.
Video of the jet coming in for a rolling runway landing with its central lift fan shaft and downward-swivelling tailpipe in action was posted yesterday by Pratt and Whitney, the firm which makes the F-35B's F135 engine:
The big fliptop lid covers the central lift-fan shaft: the fan inside is driven by a shaft from the plane's single jet engine, which also delivers thrust through the swivelling tailpipe. The smaller dorsal doors open to admit extra intake air to the engine during vertical-lift operations. There are also two smaller outlets for engine gas under the wings, used to provide roll control in the hover.
Shorter rolling landings of the sort in the vid, in which lift is provided both by the wings and the vertical-thrust machinery, are planned to be the main mode of operation for the F-35B in British service, where it is to replace the Harriers now operated by the RAF and Royal Navy. The so-called "rolling vertical landing" has already been tried out by British engineers and test pilots using the Harrier, and is expected to allow a jet to get down onto a carrier deck at sea while carrying more weight than it could in a vertical hover landing. It should also lessen wear and tear on the engine, which has to run at quite destructive power levels and temperatures in the hover.
The Royal Navy in particular is desperate to get the Lightning II as the new British aircraft carriers will not have launcher catapults under current plans, and thus the F-35B will be the only Western-made jet able to fly from them. However the RAF is far less enthusiastic, and is thought to be quite willing - indeed keen - not to replace its Harriers at all, if this means it could spend the money on upgrades to the Eurofighter Typhoon instead.
The lift fan, swivel tailpipe and other vertical-thrust bits and bobs which attach to the F135 engine are made by Blighty's Rolls Royce. Rolls are also part of the consortium developing the F136 engine, intended to offer an alternative option for buyers of the F-35B in future.
Pentagon officials including SecDef Robert Gates have tried for years to cancel the second engine so as to save its development costs, but thus far politicians in Washington have continued to fund it - arguing that competing engine providers will drive down costs in the projected, thousands-strong F-35 fleet of the future and so recoup the upfront development costs over time. The politicoes, of course, are also keen to preserve jobs in Rolls' several US factories and those of its F136 collaborator GE. ®