The Lear family is one of the pioneers of private jet aviation. Learjets have brought performance and innovation to the aviation market, starting with the original Lear 23 in 1963. Introduced in 1981, the Lear 55 incorporates successful elements of former Learjets, while adding a few design modifications of its own like a larger fuselage. Although its predecessors were competitive, Lear essentially produced the 55 to contend in a growing business aircraft market, namely one with greater cabin accommodations. Seven years later and improved even more so, the 55C model introduced delta fins, now common in Learjets.
The midsize cabin aircraft is the perfect combination of the 30-series’ turbofan engines and the 20-series’ “Longhorn” wing. Lear began replacing turbojet engines with turbofans starting with the Lear 35 in 1974. A pair of TFE 731-3A-2B engines powers the Lear 55C, providing 3,700 lbs of thrust apiece. Inspection interval is 4,200 hours. Adapted from the 28 and 29 Longhorn models, the Lear 55C features an increased wingspan and drag-reducing winglets using higher strength aluminum. Most notable, the Lear 55C vastly improved handling and performance due to longitudinal surfaces on the new delta fins.
However, engineers made huge developments in cabin space and aerodynamic capabilities. The Lear 55C fixes its engines higher on the fuselage to decrease the amount of interference drag. Also, the vertical tail’s position, 20 percent higher, enhances directional stability.
The Lear 55C can fly at a maximum operating speed of mach .81. It is capable of a high speed cruise of 450 knots, and a flight ceiling of 51,000 ft.
But the standup cabin is the aircraft’s single biggest improvement. 50 percent more cabin volume than its predecessors is enjoyed in the 55 series. The dimensions measure 5.7 ft high, 5.9 ft wide and 13.7 ft long. Rather than adding more seating, engineers chose to enhance the cabin’s comfort and amenities. The cabin typically accommodates seven or eight passengers in a configuration familiar to Lears: a club arrangement with a side-facing bench and an additional aft seat. A high-density configuration can seat ten. Also featured are external and internal baggage compartments, a half-width lavatory and a small galley/refreshment center. The expansion is sure to be noticed by passengers.
The avionics system typical of the Lear 55C’s consists of five-tube Collins EFIS-85L system, Collins AHS-85 AHRS, dual Pro Line 2 VHS comm and nav radios, WXR-350 weather radar and APS-85 autopilot.
While the Lear 55 presented unrivaled characteristics at the time of its introduction, the Lear 55C did it even better. By improving on an already innovative aircraft, the 55C variant offers the same cabin comfort with much more in performance capabilities and the design common of today’s Learjets.