Engine manufacturer GE Aviation on Monday gave an update on its class H series turboprops, which are powering four aircraft for their first flights this year.

In Zhuhai, China, the Caiga TP150 single is expected to fly in the coming days with a H85, according to Jim Stoker, GE’s president and managing executive, business and general aviation turboprops. Later this year, Nextant is expected to fly its King Air G90XT, a remanufactured King Air with H75 engines. Recent first flights include the Technoavia Rysachok utility light twin, with two H80s in March, and the Airtec L410 upgrade, with two H85s, in May.

A total of 125 H series engines have been produced and nine certifications received for as many applications. Ramp-up plans call for 90 engines to be manufactured this year and 110 in 2015, said Brad Mottier, v-p and general manager, business and general aviation and integrated systems. The H Series were designed and are manufactured in GE’s factory in Prague, Czech Republic.

Asked about key differences between the H Series and Pratt & Whitney Canada’s PT6 family, Mottier gave an example related to the combustor. The H Series has no fuel nozzle. Rather, it features fuel ports that rotate with the shaft, thus making for a very uniform fuel distribution, he explained.

Product improvements are on the way, such as additive layer-manufactured (3D-printed) parts. Integration tests are under way and the hoped-for outcome is weight reduction. In addition, electronic control should optimize propeller speed and pitch. Mottier also mentioned a reduced-RPM propeller gearbox, for lower noise and better cruise efficiency.