Aerobatic pilot and aircraft designer Walter Extra developed the Extra 300 in 1987. The Extra's shape epitomized the modern, sleek unlimited aerobatic monoplane. It was that huge canopy that made the 300 special, though, since it covered a two place cockpit.
Begining in the 80's, biplanes began to loose their dominance in aerobatic competition as higher performance aerobatic monoplanes were introduced. Unfortunatly, the unlimted monoplanes were all single seaters, so there was no way to get proper training in them with an instructer on-board. The closest thing to unlimited aerobatic trainers were the two seater Pitts Specials biplanes. Enter the Extra 300- the first unlimted aerobatic monoplane trainer.
Walter Extra took the basic layout of the Extra 230 and added a more powerful 300 horsepower 6 cylinder engine and a second seat. The Extra's fuselage is a convetional TIG welded steel tube framework covered primarily with Ceconite fabric and some aluminum. The front deck and turtle deck are carbon fiber, and can be removed for maintenance, and the cowling is of carbon fiber honeycomb construction. The landing gear struts, ailerons, elevators, and even the seats use composites. The carbon fiber skinned wing has two composite spars, the front one passing through the fuselage, and the rear connecting to each side of the fuselage structure just between the front and rear seats. The horizontal and vertical stabs are also composite, and use a single spar. This eliminates the need for the flying wires the Extra 230 used on its tail surfaces.
A characteristic feature found on many competition EA300s is the large amount of plexiglass used on the lower fuselage. Large clear panels on the floor of the cockpit, and on the sides of the fuselage under the canopy give the pilots better visibility around the shoulder mounted wing. This helps them keep an eye on the aerobatic "box" that they must stay within during competition. There is also a clear panel just below the the horizonal stabilizer. The purpose of this window is to inspect the elevator linkage to make sure it is free from jams or obstructions. The possibility of foreign objects somehow getting into the tail is a real one, since the area behind the back seat is open to the rear fuselage.
In 1993, the Extra 300 reached another milestone by being type certified by the FAA in both normal and aerobatic categories. The aerobatic certification requires that the plane able to at least withstand +6/-3 g's. It also requires that the plane withstand it's certified load limit by a factor of 1.5. Since the Extra was to be certified to +10/-10 g's, this would meant that the wing would have to be loaded to 15 g's! The Extra passed the loading tests with flying colors. In fact, the FAA usually goes on to test the wing to failure, but they could not get it to fail! They gave up after putting a load of 20 g's on the wing.
With certification, the Extra 300 also made a step toward a level of civility that had never been seen before in an unlimited aerobatic ship. Since aerobatic flights rarely last more then 30 minutes, most unlimited aerobats feature cramped, noisey, drafty cockpits, with hard, unforgiving seats. Few of these airplanes would be very comfortable for a cross country flight. The large size of the Extra (in comparision to most aerobats) allows it to feature a fairly roomy cockpit that can be outfitted with full IFR gear, comfortable seats, and even a 3-axis auto pilot. With this, the Extra has it all- unlimited aerobatic performance, comfort, and a seat for a passenger.