In 1953 Paul Poberezny and a group of other aviation enthusiasts (including the renowned aircraft designer Ray Stits) formed the Experimental Aircraft Association. During the last 50 plus years, the organization, now headquartered at Oshkosh, Wisconsin, has championed the home-built aircraft, and private pilots. The Light Aircraft Association (formerly the Popular Flying Association) performs a similar function in the U.K., including the provision of technical support and engineering inspection for home-built projects.
The EAA has, over the years, issued a series of plans for aircraft of their own design, one of which was the EAA Biplane. Paul Proberezny asked Jim Stewart of the Allison Engine Company to lead a team of engineers in the design of the EAA Biplane, an aircraft which turned out to be rated at +6g/-6g and capable of taking a range of engines anywhere from 85 to 150 hp. The aircraft was unusual in that despite having enough power to have two seats fitted, it was always intended to be a single-seater; this restricted the potential market, somewhat. Never the less, over 130 sets of plans were sold (at $20 a set), and at least 88 aircraft were completed and flown in the USA.
In 1963, Ronald Maidment built an EAA Biplane in the U.K.; the project was overseen by the PFA, which gave it a construction number of 1314. G-AVZW is now owned and operated by the ‘Zulu Whisky Group’ and is seen here at Hullavington during a Great Vintage Flying Weekend event. Power is provided by a Lycoming O-290-D (Conversion) producing about 130 hp. It is probable that the conversion was from an O-290-G, a non-aircraft rated version of the engine, used originally as a Ground Power Unit. After machining off the prominent front flange of the O-290-G, and utilizing certain parts from Lycoming O-420 and O-290 engines, a flight-capable engine can be produced at much less cost than for a ‘real’ O-290-D. Although this process is discussed on the web, and conversion manuals are available online, this conversion is NOT for the faint-hearted!
The O-290-D will burn fuel at about 7 gallons an hour in cruise, giving an endurance of about five hours, and a speed approaching 140 mph. The EAA stopped selling sets of plans for the Biplane in 1972; this coincided with their launch of the EAA Acro Sport P-8 (powered by a Lycoming O-360 of 180 hp) a close relative of the Biplane. It is a shame that more EAA Biplanes were not built, for they are a handsome aircraft!