RAMP UP Deck-mounted ski-jump assembly marks key step toward U.K. carrier-based JSF operations
Aviation Week & Space Technology / 19 Aug 2013 pp.33-35
"...Design work is also close to completion on the ship-borne rolling-vertical-landing (SRVL) system, which is being developed for the U.K. by Lockheed Martin, BAE Systems and Northrop Grumman. The SRVL technique, which will also be used by the U.S. Marine Corps while operating F-35B short-takeoff-and-vertical-landing variants from U.S. Navy carriers, enables the aircraft to land at heavier weights than possible when making a vertical landing. Initial flight trials of the F-35B, including SRVLs, are expected in 2018.
Under this technique, the aircraft will follow a conventional 2.5-3-deg. glideslope from 1,000-ft. toward the carrier until leveling off at 200 ft., where it will stabilize for a final approach at 7 deg. Flying at around 60 kt., compared to 120 kt. for a conventional carrier approach, up to 5-10 % of the overall lift will be generated by forward flight.
"This increases the recovery weight above vertical landing and enhances the bring-back load by an extra 2,000-4,000 lb.," says Atkinson. "The intention is always to stop with brakes and engine at idle, compared to the carrier landing where the intent is always to bolter (aka touch-and-go). The SRVL touchdown point is variable with ship motion, while the carrier landing point is always on the arresting wires.
Pilots will fly the approach using a stabilized and illuminated aim point on the ship's deck and a ship-referenced velocity vector on their helmet-mounted displays. The technique is being developed using a modified flight simulator at BAE's Warton, England, facility.
The company has also been running tests at its hot-gas test rig at the same site to replicate the aero-thermal environment caused by the F-35's exhaust.
"The F-35 has a much more powerful propulsion system so we have to take account of the high-energy, hot-cold flow. We looked in the simulator at the repeatability of approaches and at how much of the catwalks we would have to sterilize (heat treat). We also looked at hover transition corridors for aircraft to land. We used computational fluid dynamics and subscale model tests to protect areas from heat transfer; along with full-scale testing," says Atkinson.
BAE built a 15.7%-scale model of a QEC catwalk with containers, fuel systems, life rafts and sections of the ship's deck. It then used the hot-gas test rig at Warton to expose the model to the full-scale pressure of a F-35 gas stream. "We've been testing things like life rafts without and with all sorts of covers. We want to protect for a single pass in areas that would not normally be overflown," he adds."