To power the test itself, three “pusher sleds” are positioned at the rear of the sled. Collectively, the sleds hold as many as 120 Mk-10 “Holy Moses” rocket motors, which have been gently lowered in place by a crane. These rockets are ignited in six different stages, with each rocket motor providing 5,300 pounds of thrust for 0.89 seconds. The result is a test that sometimes breaks the sound barrier, accelerating LOIS and LARD up to 750 mph. Ejections occur about 6.7 seconds after the sled rockets ignite. By the time you hear the rockets, the seats have ejected and the test sled is already several thousand feet down the track. There’s a lot of adrenaline pumping during the full test, which lasts only about 17 seconds from initiation to when LOIS and LARD safely land. During the ejection test event, we’re looking for seat stability, fully inflated parachutes and LOIS and/or LARD descending slowly and steadily to the ground, among other key factors.
Following seat ejection, the sled is halted by 65,000 gallons of water. A scoop on the sled picks up that water, discharges it overhead, and picks-up additional water to create a reverse thrust effect that results in the equivalent of stopping your speeding car on a dime.
This is the closest simulation we have created to a real pilot ejecting from an aircraft. More than ever, we can accomplish incredible things with modeling and digital design, but these real-life tests are essential. Having this one-of-a-kind facility has been an absolutely critical part in letting us continually improve the safety, performance, and design of ACES 5.
Already a unique complex in the country, UTC Aerospace Systems is in the process of expanding our facilities at the Hurricane Mesa Test Facility to include additional structures and new sleds. With ACES 5 testing now complete for the United States’ B-2 bombers, the cutting-edge ejection seat is now undergoing further testing for potential inclusion on T-X trainer aircraft and as part of the Air Force’s Next Generation Ejection Seat program.