First Flight Expected Soon For Jet-Powered Sonex

The folks at Sonex have announced that they successfully tested the PBS TJ-100, a Czech-built small jet engine, on board their SubSonex single-seat aircraft, and they plan to begin flight tests soon. The aircraft was displayed at EAA AirVenture this summer with a different jet engine, a small Heward design derived from radio-controlled model aircraft technology, but the new TJ-100 is a full-featured production engine. The new engine has many advantages over the original choice, according to Sonex, including a dedicated oil system that eliminates the need to pre-mix engine oil with fuel, high-quality components, and pre-wired instrumentation and throttle control for "plug and play" installation. The change in engine type made it possible to accelerate the project's timeline. The test aircraft was modified to accept the TJ-100 with a new engine mount and modifications to the electrical and fuel systems. The engine tests were conducted on Dec. 18, comprising three runs with power settings up to 100 percent. Click here for a video of the tests. First flight will take place following an FAA airworthiness inspection and is dependent on cooperative weather, which is scarce this time of year at the Sonex base in Oshkosh, Wis.

Sonex Founder John Monnett spoke with EAA after the test. "We just wanted to see what the flame front out the back end and make sure we weren't having any problems of melting the tail off the airplane," he said. "We were cautious, and we melted a lot of snow." PBS is working to certify the TJ-100 to Czech civil aviation standards, according to EAA. It is currently used in auxiliary power units and on drone aircraft and can produce up to 240 pounds of thrust. It is also used on the Super Salto powered sailplane, which performs in airshows.