PIQUA, Ohio — July 1, 1997 — Hartzell announced today that it has been selected to provide scimitar propeller systems for the new Kestrel K-250. The prop for the new aircraft will feature custom blade airfoils designed by Hartzell to provide maximum performance within the intended flight envelope. The aircraft and propeller system are scheduled for certification early next year. According to Michael M. Humphreys, President of Kestrel, “Hartzell worked diligently with us to create a propeller for the K-250 … one that works well with the 250 HP Continental which operates at lower RPMs and therefore demands more from the propeller to achieve the desired thrust.”
To complement the advanced aerodynamics of the aircraft as well as its intended role as an advanced trainer, Hartzell engineers utilized a three-bladed, constant speed aluminum propeller incorporating unique scimitar blades. As a result, the prop exhibits strong low speed thrust performance for superior take-off, acceleration and climb.
In addition to maximizing low speed thrust, the design team also minimized propeller diameter (78 inches) in order to reduce the speed of the tips – where most propeller noise is generated. Resulting prop noise for the K-250 is much less objectionable than what a comparable two-bladed system would generate. Each blade in the new system will also be more lightly loaded aerodynamically, contributing to reduced vibration. The relatively short diameter of the prop also ensures ample ground clearance, leading to reduced tip erosion and an improved service life for the blades. And, as with all Hartzell “compact” series propellers, the prop for the K-250 will feature a 2000 hour TBO.
Kestrel Aircraft Company is an innovative Oklahoma-based manufacturer of composite aircraft. The K-250, one of 4 planned Kestrel aircraft, is a full-cantilever high-wing, 4-place aircraft. All Kestrel aircraft have been designed using advanced NASA aerodynamics and advanced structural carbon composite materials.
Hartzell Propeller Inc. is the world’s leading manufacturer of propeller systems, shipping product into more than 25 countries in 1996. Hartzell enjoys a 60 percent market share on turboprop airliners and 85 percent market share on corporate turboprops. The 80-year old company is also well-known for its design leadership, having introduced the industry’s first full-feathering propeller for light twins, the first fully reversing propellers for corporate turboprops and the industry’s first composite structure blades.