PIQUA, Ohio — January 30, 1996 — Hartzell Propeller and Knots 2U Inc. have collaborated on new propeller and engine cowling STCs for Piper’s popular Twin Comanche PA30/39 aircraft. The new system features a newly designed Hartzell two-bladed propeller and spinner as well as a Knots 2U designed nose bowl with an optional induction modification. The prop/spinner/cowling combination was under development for more than two years and has demonstrated significant performance gains throughout the aircraft’s flight regime.
Pilots are reporting typical performance improvements in the area of low speed thrust … shorter take-offs, as well as increased acceleration and climb. In addition, reduced drag from the modern, aerodynamic cowling is helping the aircraft improve high speed thrust (cruise) characteristics, as well.
Recent flight tests have been performed to determine maximum time-to-climb performance. These tests, undertaken in dirty (gear and flaps down), over gross configuration, on an 85° day, demonstrated an average of 14 minutes to climb from 1,000 to 10,000 MSL … a significant improvement. In addition, Twin Comanches’ with the modification are “truing-out” 10 knots faster at 18 GPH power settings. Other, specific improvements include significant reductions in noise and vibration levels, improved aircraft stability, higher cruise speeds, and reduced fuel burn.
The Hartzell constant speed propeller features aluminum blades and hub and is a member of Hartzell’s growing range of next generation, lightweight, compact propeller systems. The airfoil design features a root to tip twist distribution that maximizes performance within the airspeed range of the Twin Comanche. The redesigned polished spinner is sleeker and more bullet-shaped than the original unit and features twice the metal thickness on the aft circumference to improve long-term durability.
Hartzell Propeller Inc. is the world’s leading manufacturer of propeller systems, enjoying an 85 percent market share on corporate turboprops and a 60 percent share on turboprop airliners. The 78-year-old company is also well-known for its design leadership having introduced the industry’s first full-feathering propellers for light twins, the first fully-reversing propellers for corporate turboprops, and the industry’s first composite structure blades.
Knots 2U is a nationally recognized airframe modifier located in Michigan. The company holds more than 60 performance improving STCs with special focus on single and twin engine Piper aircraft.