com;lluedThe <strong>Merlin</strong> ... (was) designed aroundour basic philosophy of matching pressurizationto the altitude performance capabilitiesof the airplane. Our aim is to fill a voidthat existed for a light transport type airplanein the six to 10 place category thatoffers high performance and pressurizedcomfort up to 30,000 feet-an airplane thatcruises between 250 and 300 miles perhour, yet still is able to use small airportswith 2,000 to 2,500 foot runways, andthat can be marketed in the $200,000 to$300,000 price category.That is a quote from remarks made<strong>by</strong> Edward J. Swearingen Jr. in January1965 to introduce the <strong>Merlin</strong>. Boththe designer and the. airplane are stillactive, even though both the man andthe product, together with the comp<strong>any</strong>he had formed, have gonethrough m<strong>any</strong> changes.Swearingen got the airplane fromfirst flight to certification in 15 monthsand made the first customer deliverythree months later. That, in the currentcycle of four-to-six year developmentcycles, is as amazing as the differencebetween the first retail price of$335,000 and the current version's$1,970,000 (both without avionics).As the accomp<strong>any</strong>ing spotter'sguide indicates, there have been almostas m<strong>any</strong> changes to the <strong>Merlin</strong> inthe ensuing 19 years as there havebeen to the value of our dollar. But thecurrent version, the Fairchild 300,shares m<strong>any</strong> common characteristicswith the first <strong>Merlin</strong>. It is a round, tubularfuselage (round is best for pressurizationaccording to the engineers)sitting on a wing; the fail-safe approachto structures is very much apart of both, as is flush riveting. Visually,the lineage is obvious.The 300 is a development of the last66. FEBRUARY 1984
model called <strong>Merlin</strong>, the mc (modeldesignation is SA227-Tf), which wasintroduced in the fall of 1980. It hadsignificant changes over previousmodels that improved operational flexibilityand utility, maintainability andoperating characteristics. It was alsothe first g'eneral aviation aircraft certificatedto Special Federal Aviation Regu-'lation (SFAR) 41. To oversimplify, thiscategory provides a way to get aroundthe ancient and arbitrary 12,500 poundmaximum takeoff or gross weight limitthat separates light aircraft from airtransport category aircraft. For operatorsof approved aircraft, it expandsoperational options, providing increasesin both payload and range. Forthe <strong>Merlin</strong>, it expanded the envelope<strong>by</strong> 730 pounds: maximum takeoffweight increased from 12,500 to 13,230(maximum ramp weight is 13,330pounds; maximum landing weight is13,230 pounds).The tradeoff for greater operationalflexibility is more stringent standardsfor structures, systems, operations andcrew qualification. Performance requirementsfor such parameters as balancedfield length and single engineclimb are more demanding. Fire protectionstandards are higher. For instance,fire detection and extinguishingsystems must be installed in theengine compartments, and fire containmentproperties must be satisfactorilydemonstrated (fire walls are stainlesssteel in the <strong>Merlin</strong> IIIC/300).Flammable fluid lines must be isolatedfrom electrical sources. Interior materialsmust meet air carrier fire resistancestandards.Any aircraft operated at weightsabove 12,500 pounds requires the pilotin command to be type rated. Initially,<strong>Merlin</strong>s that were operated underSFAR 41 required a two man crew, althoughthey now are approved for singlepilot operation.In terms of structure and systems,the <strong>Merlin</strong>s have reflected the designphilosophies of heavy transports morethan some <strong>other</strong> general aviation turboprops.In its current form, it includesa fail-safe primary structure,fail-safe structures at all critical loadpoints, multiple spar webs and <strong>other</strong>features to ensure that, in the event offailure of or damage to <strong>any</strong> critical airframeelement, structural integrity ismaintained. The airframe has a safelife of 35,000 hours. Environmentaland operational systems are dualthroughout. The electrical system employsthree buses.The horizontal stabilizer is mountedwell above the fuselage, basically acruciform tail. It is pivoted near therear spar, and the entire surface moveswith pitch trim commands throughelectrically operated dual jack screws.There are visual and aural trim indicatorsin the cockpit. The pilot and copilottrim systems are separate.The primary flight controls are actuated<strong>by</strong> directly linked push rods. Theslotted flaps are hydraulically actuatedand mechanically linked to preclude asplit flap condition.Earlier <strong>Merlin</strong>s had a relatively slow,high-drag gear extension and retractionsystem that was gradually improvedthrough several modelchanges. The mc iptroduced an improvedsystem coupled with a new enginecowl design that greatly improvedserviceability and access (the comp<strong>any</strong>claims that an engine can be disconnectedand removed in less than 30minutes without requiring rerigging afterreplacement). The new gear systemoperates more quickly. It also eliminatedthe high-drag door on the nose-AOPA PilOT • 67