Tests Simulate A Carrier Landing

The carrier variant of the F-35 Lightning II is undergoing drop testing at the Vought Aircraft facility in Dallas. Vought is one of only two test labs in the country that has full-scale carrier suitability drop test capabilities, the other being Boeing's St. Louis plant. According to John Vaught, Test Lab Manager, the F-35 Drop Test Program in total represents a very high level of complexity generally not seen on previous drop test programs. "The ability and know-how to do these drop tests are very unique," he said.

 
F-35C Drop Test

Hundreds of wires snake along the light green test fuselage, which is suspended in a harness just below the rafters of the test facility. Those are connected to an array of instruments that are streaming signals back to a computer which will compare the data to computer models. The testing is necessary because as a fighter jet approaches the deck of a carrier, forty-six thousand pounds of airplane traveling at 138 knots hits the deck at full military power, creating enormous stress on the airframe and landing gear. Every part of the gear must withstand that stress repeatedly with no structural failure. F-35 Drop Test Director Tom Foster says the instruments measure measuring strain, acceleration, deflection and load data.

There are 512 data channels connected to this aircraft. Twenty-five hundred data samples are gathered per second per channel during each drop test for this aircraft. High speed video of each landing gear is simultaneously recorded at two thousand frames per second and synchronized with the aircraft test data for post-test, image-to-data correlation. In other words, each high speed video picture can be directly compared to the load and deflection data measured and recorded on each landing gear.

Eventually, there will be about 53 landing gear drop tests at various aircraft roll, pitch and landing sync rates performed on this one jet. Dummy ordinance will eventually be loaded onto the test airframe to gather data for maximum landing weight conditions.

F-35 Conventional Take Off And Landing Variant

With the level and type of test capabilities the labs possess, Vought has a long, and very reputable history of accomplishing carrier suitability testing for the Navy, said John. "We can go all the way back to the XC-142, F-8, A-7, S3A, and now the F-35. All of these legacy aircraft programs required fullscale drop testing to qualify for aircraft carrier operations. Full-scale dynamic tests of this nature present a very complex test set of problems to run," he said.

The F-35 tests at Vought should be completed within the next few months. The Carrier Variant F-35C should make its first flight in the second quarter of 2010.

FMI: www.voughtaircraft.com