Amendments allow Raisbeck to halve cost of Learjet 35/36 performance-improvement upgrade to below $100,000
Raisbeck Engineering has received US supplemental type certification for its revised ZR Lite performance-improvement package for the Learjet 35/36. Modification of the first customer aircraft is scheduled to begin in mid-November.
The Seattle-based performance-enhancement specialist has significantly revised its ZR package to reduce its cost to below $100,000, achieved by eliminating the double-delta inboard wing leading-edge gloves. Flight tests without the leading-edge extensions show a drag reduction of 6%, compared with 10% with the gloves installed, says company president Jim Raisbeck.
Raisbeck moved to cut the cost of the ZR package from over $200,000 after seeing prices for the out-of-production Learjet 35/36 decline, and noting the low percentage of the fleet that had undergone the $150,000-200,000 upgrade to meet US domestic reduced vertical separation minimum requirements.
The revised kit includes horizontal winglets inboard of the tip tanks and behind the wing trailing edge; extended-chord and twisted composite wing flaps; and leading-edge vortilons. The modification also has a new take-off flap setting and re-optimised take-off speeds to recover some of the performance improvement lost with removal of the leading-edge gloves. Raisbeck says the revised ZR Lite package provides a 6%-plus increase in range, shorter climb times, higher initial cruise altitudes, lower fuel burn and increased take-off weights from shorter or higher-altitude airports.
GRAHAM WARWICK / WASHINGTON DC
Source: Flight International
