In an audacious display of confidence, the U.S. Marine Corps and the Joint Strike Fighter (JSF) program office demonstrated short take-off and vertical landing (STOVL) tests of the F-35B Lightning II to reporters onboard the amphibious assault ship Wasp on Oct. 18.
Flown by Marine Lt. Col. Fred Shenk, F-35B test aircraft BF-04 flew a series of short take-offs and vertical landings onboard the 40,000-ton warship
sailing off the Virginia coast in front of a small gaggle of press that had been flown in earlier in the day.Naval F-35 test director Marine Col. Roger Cordell said that testing onboard the Wasp, which will end this Thursday, has gone exceedingly well. Already the test pilots have flown about 60 of the 67 required sorties, with more scheduled for later today. "We feel like we're running when we intended to crawl," he said.
The team started off the flights by using the flight envelop cleared for the AV-8B Harrier as a starting point before expanding into new territory, Cordell said. From that initial envelop, the testers expanded it up to 30 knots of headwind and down to 10 knots of headwind. They also flew the jet with a 15-degree crosswind.
The aircraft has flown very well during the sea trials, said Marine Lt. Col. Matt Kelly, lead F-35 test pilot at Naval Air Station (NAS) Patuxent River, Md. While he couldn't compare the jet directly to the Harrier since he was an F/A-18 Hornet pilot, Kelly pointed out that the sea trials are his first experience operating from an amphibious assault ship, which is a testimony to the F-35B's excellent handling characteristics.
"I have found this airplane to be just a really nice airplane to fly in the shipboard environment," he said. "Prior to two weeks ago I had never landed or taken-off from this type of ship… It's a pleasure to fly."
Kelly added that the F-35B is easier to handle on the flight deck than he had imagined it would be. The challenge is not landing the aircraft but rather "putting the nose tire in a 1-foot-by-1-foot square box," he said.
In up and away flight, the F-35 handles magnificently, similar to a clean F/A-18 Hornet with more power, Kelly said. Additionally, during daylight hours, the aircraft's previously troublesome helmet-mounted display is now performing very well unless displaying video imagery, he said.
For getting off the ship, Cordell said that there are three short take-off modes that the team tested: manual, semi-automatic and fully automatic. Originally, the test team had only planned to do manual take-offs, but soon expanded the scope to include the other modes. Kelly said he had flow about a half-dozen automatic mode take-offs himself.
Cordell said that one piece of good news is that the "outflow" from the jet's exhaust while hovering is less intense than expected. "It's counterintuitive, but the jet has a less harsh environment hovering at 40 feet than it does at 100 feet," he said. Engineering models had predicted the outcome, but skeptics - Cordell included - had doubted those conclusions.
The hazard zone around the jet therefore has shrunk to about the same size as that of a Harrier, he said.
Similarly, the "outwash" on take-off is far less harsh than anticipated, Cordell said.
A second set of sea trials will be done early next year, Cordell said. Those trials will put the F-35B's mission systems and weaponry to the test. The team will also test night operations at sea, he said.
Later, the F-35B will return to the sea for a third time to conduct operational testing in around the August of 2013, Cordell added.
This initial set of sea trials for the F-35B is as much about the ship as it is about the aircraft.
Ansis Kalnajs, the test director for Naval Sea Systems Command (NAVSEA), said that the ship had been extensively instrumented for the test series. The instruments measure everything from sound, to heat, the velocity of the exhaust hitting the flight deck.
In order to facilitate the trials on the Wasp, some antennas have been removed, others covered, and some equipment needed to be moved to accommodate the F-35B's larger wing span compared to the AV-8B Harrier II, Kalnajs said. The ship's "tram line," which guides pilots during take-off and landings, had to be shifted by 34 inches, he said.
The flight deck and a lot of the ancillary deck equipment had to be extensively instrumented to measure the impact on the ship, Kalnajs said. From all indications, the test results are matching predictions, he said.
NAVSEA also used the F-35B trails onboard the Wasp to evaluate some non-skid material on one of the deck spots on the giant vessel, Kalnajs said. The new material was tested on a 90 square foot spot, said Navy Capt. Brenda Holdener, commander of the Wasp.
The rest of the flight deck is covered in standard material, however parts of it look different because it is newer, she said. Observers had questioned why portions of the Wasp's flight deck had a different hue than other parts of the deck surface.
Non-skid materials have and continue to be a vexing problem for the Navy, breaking down after only six or seven months, Kalnajs said. He said the Navy hopes the newer material being evaluated will last for years at a time.
The Wasp also conducted trials on how the aircraft fit into the ship's aircraft elevator and massive hangar bay, Holdener said. Hangar deck crews found that the F-35B is much easier to handle below deck, she said.
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