 Excalibur aircraft are easily distinguishable from standard Twin Bonanzas and Queen Airs by the landing gear doors and the more rectangular engine cowlings of the Excaliburs compared to the rounded cowlings of the originals.The Excaliburs led to the first Swearingen design, the SA26 Merlin, which could be described as a pressurized Excalibur.The Merlin had modified Queen Air wings with redesigned fuel tanks, Queen Air horizontal tails, and Twin Bonanza landing gear.