First F-35 resume flights tests

Lockheed Martin's first F-35 Joint Strike Fighter (JSF) returned to flight on 5 March after a software update to incorporate performance data from its first seven flights.

Aircraft AA-1 is expected to fly twice weekly as the company continues to expand the flight envelope.

The second JSF - the first short take-off and vertical landing (STOVL) F-35B and the first with weight-optimised airframe - is now scheduled to fly in May-June 2008.

Final assembly of the aircraft, BF-1, is already under way at Lockheed's Fort Worth, Texas plant.

Source: Flight International

Picture: Lockheed Martin’s F-35 Joint Strike Fighter soars on first afterburner take-off
By Graham Warwick

The F-35 Joint Strike Fighter made its first afterburner take-off from Lockheed Martin’s Fort Worth, Texas plant on 13 March. “It was an amazingly steep climb-out,” says company spokesman John Kent.

The first F-35, aircraft AA-1, is powered by a Pratt & Whitney F135 turbofan capable of producing more than 40,000lb of thrust with full reheat. The departure was so steep because test pilot Jon Beesley had to stay within the 250kt airspeed limit for the initial climb-out.

AA-1 returned to flight on 5 March after a five-week stand-down to incorporate scheduled software and hardware upgrades. This included updating the software to incorporate performance data collected during the first seven flights since the F-35’s maiden sortie on 15 December.

“Before the first flight we set the control limits very tight, as a precaution, so the systems were very sensitive,” says F-35 programme general manager Dan Crowley. “Now we have set the parameters to the right level.” This should reduce false alarms from sensors in the fuel and other systems, he says.

One software update tackled the air-data sensor mismatch caused by airflow around the large single nosegear door. This was producing slightly different angle-of-attack readings from the left and right air-data probes. “It was just 1-2º, but now it is corrected,” says Crowley. All subsequent F-35s will have two smaller doors.

A borescope inspection of the F136 engine was also conducted while the aircraft was stood down. “It was okay, so we reinstalled it,” says Crowley. Flights with the helmet-mounted display – the primary flight instrument on the F-35, which lacks a head-up display – are expected to begin shortly.

Over its first seven flights, each lasting around an hour, the F-35 reached Mach 0.8, 23,000ft and 16º angle-of-attack. The aircraft is scheduled to fly twice a week to continue expanding the flight envelope as Lockheed assembles the second JSF – the first short take-off and vertical landing F-35B – which is expected to fly in May-June next year.

Crowley says AA-1 behaved impeccably over its first series of flights. “Every time, it returned Code 1, ready to fly again. That is unheard of for a flight-test article,” he says. Test pilot Beesley has said the aircraft has “remarkable flying qualities”.

Source: <a href="http://www.flightglobal.com/articles/2007/03/14/212602/picture-lockheed-martins-f-35-joint-strike-fighter-soars-on-first-afterburner.html" rel="nofollow">flightglobal.com</a>

Lockheed Martin's F-35 Joint Strike Fighter begins manoeuvre tests

Flightglobal.com 23 March 2007
by Guy Norris

Lockheed Martin’s F-35 Joint Strike Fighter has completed its first manoeuvring flight tests, complete with full-stick rolls.

"It worked exceedingly well," says F-35 chief test pilot Jon Beesley, who praises the aircraft and its "robust" handling characteristics.

The first 360º rolls took place during the fighter’s ninth test flight on 20 March. The first F-35, aircraft AA-1, is expected to make its 10th flight any day now, and Lockheed expects to complete initial airworthiness tests over the next few sorties.

"The aircraft is very stiff compared to the F-22 in which you feel as if you're at the end of a diving board. With the F-35 you're standing at the other end," Beesley told a symposium of test pilots late last week.

One peculiarity of the JSF design, he says, is the splitterless inlet which "picks up an extra 2,000lb thrust" as the aircraft accelerates between 80kt and 100kt for take-off. The jump in thrust is "definitely noticeable in the cockpit," Beesley says.

Speaking at the Society of Experimental Test Pilots meeting in San Diego, California Beesley also praised the F-35's Pratt & Whitney F135 engine, which produces "perfect linear thrust" throughout its 40,000lb-plus power range.

Source: <a href="http://www.flightglobal.com/articles/2007/03/27/212940/lockheed-martins-f-35-joint-strike-fighter-begins-manoeuvre.html" rel="nofollow">Flightglobal.com</a>

I'd really like to see video of the "steep climb-out" described.

The mention of the F136 engine is probably a typo, as the AA-1 is F135 powered.

-- Shaken - out --

Looks like the pilot is pulling the nose up to keep acceleration in check.

That's exactly what he's doing because the engine is so powerfull.

Fantastic intake howl (resonance) it sounds like a real airplane.

Gums do you have any comments compared to the F100 / F104?

Loud? LOUD?? Try a B-58 with four J-79s at max burner. Or two B-58s during minimum interval takeoff (MITO). Madewooden, the B-52 has only eight engines.

You'll need to find somebody REALLY OLD to have heard an F100 or F104... jeez, somebody in his twenties in the 1950 or 60s.