NASA will soon test progress on a key tool to measure the unique “sonic thumps” that its silent supersonic X-59 research aircraft will make during flight.
The shock-sensing probe is a cone-shaped airborne data probe designed with specific characteristics to capture the unique shock waves generated by the X-59. Researchers at NASA’s Armstrong Flight Research Center in Edwards, California, have developed two versions of the probe to collect accurate pressure data during supersonic flight. A probe has been optimized for near-field measurements, capturing shock waves that occur very close to X-59. A second shock-sensing probe will measure the mid-field, collecting data at altitudes between 5,000 and 20,000 feet below the aircraft.
When an aircraft flies supersonic, it creates shock waves that travel through the surrounding air, creating high-pitched sounds. The X-59 is designed to deflect these shock waves, reducing high-pitched booms to quieter thuds. During the test flights, an F-15B aircraft with a shock-sensing probe attached to its nose will fly alongside the X-59. The approximately 6-foot probe will collect thousands of continuous pressure samples per second, capturing changes in air pressure as it flies through the shock waves. Data from the sensors will be critical to validating computer models that predict the strength of shock waves generated by X-59, the centerpiece of NASA’s Quest mission.
“A shock-sensing probe serves as a source of truth, comparing predicted data to real-world measurements,” said Mike Frederick, NASA’s principal investigator for the probe.
For the near-field probe, the F-15B will fly behind the X-59 at an altitude of about 55,000 feet, using a “follow-the-leader” setup to allow researchers to analyze shock waves in real time. allows to. The intermediate field probe, which is intended for separate missions, will collect more useful data as the shock waves move closer to Earth.
The probe’s ability to detect small pressure changes is particularly important for the X-59, as its shock waves are expected to be much weaker than those of most supersonic aircraft. By comparing the probes’ data with the predictions of advanced computer models, researchers can better assess their accuracy.
“The probe has five pressure ports, one at the tip and four around the cone,” Frederick said. “These ports measure the static changes in pressure as the aircraft flies through the shock waves, which helps us understand the shock characteristics of a particular aircraft.” The ports combine their measurements to calculate local pressure, speed and direction of airflow.
Researchers will soon evaluate the upgrade to the Near Field Shock Sensing Probe through test flights, where an F-15B-mounted probe will follow another F-15 during supersonic flight and collect data. Upgrades include having the probe’s pressure transducers — devices that measure air pressure on the cone — just 5 inches from its ports. Previous designs placed these transducers about 12 feet apart, delaying recording time and distorting measurements.
Temperature sensitivity on previous designs also presented a challenge, causing accuracy to fluctuate with changing conditions. To solve this, the team designed a heating system to maintain the pressure transducers at a constant temperature during flight.
“The research will meet the resolution and accuracy requirements from the Quest mission,” Frederick said. “This project demonstrates how NASA can take existing technology and adapt it to solve new challenges.”