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a prefix letter (B50, C50, etc.) to denote significant changes. These were usually major engine upgrades or gross weight increases. An added suffix letter (D50A, D50B, etc.) signi- fied minor changes, like the entry steps and doors, seating configuration, and other refinements.
The initial production Model 50 used geared Lycom- ing GO-435 engines of 260hp, turning two-bladed wooden propellers. Only 13 were built before Beech introduced improved versions. The B50 added a third side window. The C50 and D50 upgraded engine horsepower to 275 and 295, respectively, with Lycoming GO-480 engines. Subsequent D-models would incorporate better boarding steps, then a right-rear airstair door. The E50 got 340-hp, supercharged, GSO-480 engines. The F50 introduced fuel injection via the IGSO-480 (also 340hp). Variations on that engine would carry the T-Bone through its final production version, the J50.
Interior configurations would also vary widely. Eventually, the benches could be exchanged for two individual seats. The right-front seat slides to the center to allow the use of the center-mounted co-pilot controls. With the introduction of a third row of seating, many layouts became available, still forward of the aft baggage door or airstair door, as equipped. Four seats in a club configuration would have been the most passenger-friendly by today’s standards. A left-side divan with seating for three, facing sideways, could be combined with second and third-row right-hand seat(s). The aircraft could be certified for up to eight oc- cupants in the highest density configurations. With fewer
seats, refreshment centers, foldable work tables, and even a flushable potty were options on later models.
Ed’s Swords
Like so many great designs in aviation, the Twin Bonanza generated many after-market modifications. Extended range fuel-cells, instrument panel reconfigurations, extended baggage compartments, a slimmer nose cone allowing the installation of a radar unit, gross weight increases, and a single-piece “speed-sloped” windshield are just a few of the approved mods.
However, famed designer and engineer Ed Swearingen developed the most extensive and comprehensive modifica- tions. His initial “Excalibur” models were re-engined with Lycoming IGSO-540’s (380 hp). New doors fully enclosed the gear when retracted. The significant power increase and equally significant drag decrease, coupled with other performance-enhancing mods, made Swearingen’s T-Bones the ultimate versions. All were customized to the buyer’s desires and incorporated various mods. Thus, no two were exactly alike. His final iteration replaced the bulky geared engines with direct-drive, 8-cylinder Lycoming IO-720s, developing 400 hp each. The bulbous production cowlings (originally designed to house geared Franklin engines) were replaced with streamlined cowls. Marketed as the “Excalibur 800,” a cruise speed of 245 mph was claimed (though 220 mph economy cruise was more realistic). An estimated 44 T-Bone airframes underwent Excalibur conversion.
Above Eastsound, Washington
March 2024 / TWIN & TURBINE • 19
PHOTO COURTESY OF DWIGHT BARTON.