Design Improvements for the Zenith 601 HDS

Important Note

This page and additional links describe design improvements of the Zenith 601 HDS implemented in our plane N314LB. Anyone using the information does so at his/her own discretion and risk, and no responsibility or liability is expressed or implied. Bottom line, we are responsible for nothing.

Construction

Mel Asberry (expert builder, EAA Flight Advisor and prize-winning Technical Advisor, Designated Airworthiness Representative) and I (Klaus Truemper, novice builder and owner of N314LB) built the plane from a Zenith kit. Several minor design changes were made during construction. During the period 1995-2004, I made additional design changes, including a new engine cowl, mounting of radiator inside cowl, and wing root fairings. Lester Palmer provided expert assistance for the fiberglass work involved in some of the latter changes.

Statistics

Completed December 1995. Empty weight: 628 lbs. Gross weight: 1,200 lbs. Engine: Rotax 912UL. Propeller: GSC, three blades, wood. It is pitched so that the engine achieves 5,400 rpm with full throttle at 3,000 ft MSL. Center tank (8.5 gal) and two tanks (6.5 gal each) in wing lockers have 21.5 gal total capacity. Note: The newer Zenith 601 HDS design uses two leading-edge tanks instead of the three-tank design.

Endurance and Cruise Speed: At 4,700 rpm and 7,500 ft altitude, endurance is 5.7 hrs @3.75 gal/hr; cruise speed is 95 KTAS @ 900 lbs total weight, and it is 90 KTAS @ 1100 lbs total weight.

Power-off stall @ 1,020 lbs is 42 KIAS. Power-off best glide @ 1,020 lbs is 65 KIAS with 650 ft/min sink rate, which corresponds to a glide ratio of 10:1. Ceiling @ 1,100 lbs total weight is 15,000 ft density altitude. Minimum power to stay aloft @ 850 lbs total weight and 3,000 ft density altitude is 3,400 rpm (= 18 hp), producing 54 KIAS.

TTAE (Total time Aircraft & Engine) (January 2009): 1,150 hrs.