NASA’s X-59 calls in Texas for key tests

It seems the path to a future that includes practical commercial supersonic air travel on land requires a substantial pit stop in Fort Worth, Texas.

Who knew?

Aeronautical innovators at NASA and Lockheed Martin have done just that. They have long anticipated this milestone in the assembly and testing of the X-59 Quiet SuperSonic Technology (QueSST) aircraft.

Although the X-59 QueSST is built by Lockheed Martin at its Skunk Works facility in Palmdale, California, the aircraft had to be moved to another Lockheed facility in Texas for a series of extensive structural tests before returning it. on the West Coast.

But let’s go back a bit.

NASA’s X-59 is a one-of-a-kind aircraft designed to fly at supersonic speeds without making annoying, if not alarming, sonic booms below.

Instead, due to its unique shape, the X-59 should produce quieter sonic “thumps” that can barely be heard on the ground – if at all.

Current rules prohibit aircraft from flying faster than the speed of sound above the earth. These rules are based on noise, not speed. If the X-59 can publicly demonstrate that an aircraft can fly supersonic at an acceptable noise level, then these rules could be changed.

If that happens, NASA’s X-59 technology could be applied to new aircraft designs so that commercial airlines can introduce faster-than-sound flights capable of accelerating people from ocean to ocean. the other in half the time.

“That’s what we’re all working so hard to make possible,” said Walter Silva, principal investigator at NASA’s Langley Research Center in Virginia. He is also responsible for NASA structures for the X-59, so he is directly involved in the plane’s visit to Texas.

OK, so what’s going on in Texas?

Construction of the X-59 in California had made enough progress where all the major structural parts—wing, main body, tail, and nose—were assembled and power could be turned on for the first time.

The next main task was to ensure that the aircraft structure would not break in flight when exposed to low and extreme stresses.

Mike Buonanno, a Lockheed Martin aerospace engineer who is the company’s vehicle lead for the X-59, explained why packing up the X-59 and trucking it to Texas in late December was the best way to prove it.

“Our Texas site has existing facilities to perform the types of testing needed. It would have been expensive and time-consuming to design and build them from scratch in Palmdale. But in Fort Worth, they have the perfect facility with a full control room and all the necessary support equipment to perform these tests very efficiently,” Buonanno said.

The company’s Fort Worth plant is where the F-16 Fighting Falcon was built for many years. The test equipment still available required some modifications to handle the longer nose of the X-59 compared to the F-16, but these changes did not hinder.

“Our people in Fort Worth were able to touch down from the moment the plane arrived from Palmdale,” Buonanno said.

feel the pressure

NASA has three goals for X-59’s stay in Texas in terms of structural proof testing.

“The first objective is to ensure that the aircraft can support the expected loads during flight,” Silva said.

Loads, in this case, means anything that would exert pressure or stress on the structure of the aircraft. Typically, these types of stress occur when the aircraft experiences turbulence, makes rapid turns, and during landing, among other things.

Since the plane does not actually fly, the tests are performed with the plane sitting on hydraulic jacks connected directly to the structure. Arms that press against areas of the aircraft, such as the top of the wing, are also used.

How much stress is too much? Buonanno explained that the loads applied to the X-59 are 25% greater than any load the aircraft was designed to see in actual flight.

Because the X-59 is not a prototype for a series of aircraft, none of the tests are designed to see how much stress a part might experience before breaking. This type of “test to destruct” is only seen in large production runs where an aircraft can be retired and sacrificed.

“In any case, there are all sorts of safety features built into the tests so that if something that we don’t want to happen is detected, everything shuts down and everything goes into a safe position” , Silva said.

The second objective is to calibrate the sensors built into the X-59 which are designed to tell the pilot the amount of stress measured at that point in the aircraft. This is done by comparing what the sensors are saying with the known amount of stress applied during a test.

“The third goal is to take the data and compare it with the computer models we used to design the plane in the first place and make sure that what we thought was going to happen turned out to be right and that the aircraft is being built as planned,” Silva said.

In the last week of January, about 80% of structural testing was complete, and all is well.

“Everything is going brilliantly, and nothing bends in a way that we weren’t expecting,” Buonanno said.

always ahead

Once all structural testing is complete, the team – which includes representatives from NASA and Lockheed Martin of Palmdale – will focus on performing fuel tank calibration tests.

The X-59’s fuel tanks will be filled and the remaining fuel sensors inside will be checked, not only with the aircraft sitting level, but with pitch and roll.

Once this work is completed, the X-59 will be returned to Palmdale. The exact timing of this return remains unknown at this time.

“We’ll be in Fort Worth for as long as we need, until we believe the data is good and everything has been executed to everyone’s satisfaction.” Silva said.

Once back in Palmdale, the X-59 will have the rest of its major systems and subsystems installed – its GE engine, landing gear, cockpit displays, and more. – in the hope that it will be ready for the first flight at the end of this year.

When that happens, the world will focus on the California high desert where aviation history will once again be written.