Another Walter Beech mod gets STC'd

LoneStar Propjets of Waco, Texas, has received an STC to replace the Pratt & Whitney Canada PT6 turboprops on the King Air 90 through C90 series with Prague-designed Walter M601E turboprops and Avia Hamilton five-blade propellers. The converted airplane, known as the “Power 90,” has a “substantial increase in both climb and cruise performance,” according to LoneStar. For the past two years a Walter conversion for C90 and E90 King Airs has been offered by Performance Conversions of Clintonville, Wis. Just three conversions have been made. The two installations differ in several aspects, including pricing, how the engines are mounted, cowling configuration and exhaust changes.