In certifying its E1000 turboprop single, Epic Aircraft had its share of setbacks, including some full-scale pressure test failures. But the company-which started in 2004 with the Epic LT, a single-engine turboprop carbon composite kit plane-learned and refined the design and re-tested and now has a robust composite airframe tested to about twice the highest load expected during service. Although it had a chance to reduce time (and cost) of flight testing the E1000 by choosing a less powerful version of the Pratt & Whitney PT6A-67A engine. Epic made the decision to stick with the 1200-HP version used on the LT to retain the performance, and consequently spent more than 1400 test flight hours for certification. The E1000 has additional design margin to allow for large flaw size (making detection easier) and can even sustain normal flight loads with only one of its two redundant carbon composite spars. Proving out the quality of the bonded assemblies involved years of data collection, tens of thousands of data points and rigorous process control-including testing each mix of adhesive. The extensive use of carbon composites on the airframe saves weight, which Epic used to improve the soundproofing and comfort of the cabin (one of the major complaints about small turboprops).
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