NASA's X-59 aircraft has been marching toward a fest flight since it entered development in 2016 with the goal of bringing back commercial supersonic travel. Next, the agency will test jet-mounted shock-sensing cones to measure its "sonic thuds."
Always one to enjoy a challenge, NASA has been working on the X-59 for about nine years, despite a total ban of civilian supersonic flights in the United States for over 50 years. The space agency believes it can overcome the main objection to such flights: the thunderous sonic booms created when a plane travels faster than the speed of sound, a rate of acceleration known as Mach 1. Those big booms led the Federal Aviation Authority (FAA) to ban the sonically disrupting flights in 1974, effectively putting an end to supersonic commercial travel.
The X-59 aims to get around the ban thanks to its unique aerodynamic hull and wing design that shuttles the boom created by breaking the sound barrier upwards instead of downwards, creating nothing more than a sonic "thump." NASA says, the resultant noise shouldn't sound much louder than the slam of a car door to someone back down on the ground.
As part of the plane's next round of tests, the space agency has announced that it's designed a set of cone-shaped probes that will be mounted on F-15B jets to measure exactly what happens to the air when the X-59 goes supersonic. One probe is designed to capture shock waves quite close to the area where the X-59 will generate them, while the other is meant to pick up shockwaves at altitudes between 5,000 to 20,000 feet (1,524 - 6,096 m) below the plane
“The probes have five pressure ports, one at the tip and four around the cone,” said Mike Frederick, NASA principal investigator for the probes. “These ports measure static pressure changes as the aircraft flies through shock waves, helping us understand the shock characteristics of a particular aircraft.” The ports aggregate their readings to come up with measurements of airflow direction, local pressure and speed.
The probes will first be tested as one F-15 chases another as it goes supersonic, with the goal of eventually using the jet-mounted cones to play "follow-the-leader" with the X-59 itself. Gathering the precise data about how the craft deflects the noise from breaking the sound barrier will help verify computer simulations and allow NASA to fine tune the craft's design to make it as quiet as possible.
“A shock-sensing probe acts as the truth source, comparing the predicted data with the real-world measurements,” said Frederick.
In the first design of the probes, the transducers that measure the air pressure on the cone were about 12 ft (3.6 m) away, which led to a significant amount of delay and distortion in the readings. The new iteration has the transducers just five in (12.7 cm) from its ports. The probes also have an in-built heating system to keep the transducers at a consistent temperature during the test flights.
While there's still no word on when the Lockheeed Martin-built X-59 will make its maiden flight, the craft was unveiled in a ceremony earlier this year, which you can watch in the following video. The space agency also announced that it fired up its engines for the first time just last month, so flight testing shouldn't be too far behind.
Source: NASA