Installed Engine thrust test facility at Pad 18 gets facelift, new equipment Published Aug. 10, 2011 By Diane Betzler Staff writer EDWARDS AIR FORCE BASE, Calif. -- The Installed Engine Thrust Test Facility at Pad 18 has been in service at the flight test center since the mid-1950s and Gary Peddecord, systems automation and sensor calibration specialist, thinks of the pad and the measurement system as "his baby." Since this baby hasn't had a major renovation since 1989, officials say it's time for a facelift. Peddecord said that as far as he knows, the thrust test facility at Pad 18 is the only operational thrust test facility in the United States that is able to test large aircraft and measure the amount of thrust their engines put out after being installed into an aircraft. "There's one [thrust test facility] in Pax River, [Naval Air Station Patuxent River, Md.] but it's on a much smaller scale built for fighters only. They cannot test big aircraft there," Peddecord said. "Our customers need to verify what the static thrust is after they take an engine that is rated at 30,000 pounds and put it into an airframe. The customer needs to know exactly what that engine is producing," Peddecord said. Other methods of measuring engine thrust are not totally accurate, he said. "You can use computer models, play with digits, spreadsheets and formulas all you want, but at some point in time you've got to put that one-pound of weight on a one-pound scale and verify that it really is one pound," he said. Contractors and vendors send along with the engines data that predict the engine's thrust capability, but he said it's his job to verify the figures. At the thrust test facility, technicians handle thrust testing for such aircraft giants as the C-5 Galaxy and B-52 Stratofortress, to smaller aircraft like the F-16 and T-38. "We also do some commercial airplanes," Peddecord said, which is evident by photos of different airliners adorning the walls inside the underground control room. "From a Cessna to a C-5, we don't know of any aircraft we can't test," Peddecord said. The facility has four thrust tables, or horizontal scales, which have been a part of the facility since it was built. During a renovation in 1989 the tables, as well as the underground concrete walls, stairs, hallways and tunnel were painted with lead-based paint, which needs to be removed. The facelift involves a lot of scraping, sandblasting, sanding and repainting and is expected to take about four months to complete. "After all the sandblasting and sanding is done, the floors and walls will be resealed to keep the moisture out," he said. Peddecord said because the facility is used infrequently the lead-based paint hasn't been a concern until it began peeling. "It's not like we're here 24-7," Peddecord said. He said his team runs an average of six thrust test programs a year with each program running between two to three days, while occasionally some might run two or three weeks. To run an engine thrust test the aircraft is placed on one or two of the four thrust tables, depending on the size of the aircraft. "Each table has two load cells, we measure the voltage out of each load cell and compare that to a known value based on our calibration," Peddecord explained. Virtually every aircraft the Air Force has flown since 1955 has been tested at this facility at some point in its development, he said. When not conducting engine thrust tests at Pad 18, Peddecord can be found at Building 1600 running the instrumentation calibrations standards lab. Needless to say, there won't be any engine thrust testing done while Pad 18 is undergoing renovations, but Peddecord intends to put the downtime to good use. "I'll be installing new software and upgrading the instrumentation system," he said. He and his team are going to use funding wisely, he said. "We're installing new computers, developing new software and reconfiguring the load cells." "As the Air Force is placing more emphasis in the UAV arena, having removable load cells will allow us to configure the thrust stand to more closely match the lower thrust ratings of these types of aircraft," he said. The new load cells are replacing 1980s technology and will allow the yearly calibration of the thrust stand in less than a day - something it previously took six man-days to do, Peddecord said. The software is in place just waiting for the refurbishment to take place, which will happen after the contract renovation is completed. Renovations to the pad and the underground facility are expected to begin Aug. 5, with a completion time scheduled for early December. Because of a tight budget, Peddecord said the control room is going to be left as is. "The estimate for what we wanted to do came in much higher than the amount of money we had to spend, so we had to trim back on the renovations."