Overcoming vs. Overreaching
In their push to advance the state of the art, airplane designers often reach a point where performance aspirations run headlong into engineering or manufacturing realities. Two articles in this issue demonstrate that sometimes designers overcome those realities, and sometimes they don’t.
In his story about the troubled development of the B-29 Superfortress in the September 2011 issue, Stephan Wilkinson recounts how Boeing, faced with using an engine that had a nasty tendency to catch fire, forged ahead with testing and production, eventually turning out nearly 4,000 of the heavy bombers. There was a war on, after all, and the need to take the fight to the Japanese Home Islands eclipsed all other considerations. By the time Japan surrendered following the destruction of its industry by Twentieth Air Force B-29s and the atomic bombings of Hiroshima and Nagasaki by “Silverplate” Superfortresses, the engine problems had been largely worked out—but not before thousands of B-29 crewmen had paid the ultimate price.
A far different outcome awaited the developers of the Junkers Ju-288, as Robert Guttman explains in “Extremes." Saddled with unrealistic performance expectations and, like the B-29, with a complex engine that still had a lot of bugs to work out, German engineers turned out prototype after prototype—all of which were deemed unsatisfactory. In the end, after spending the equivalent of 20 million wartime dollars, the Germans canceled the project, with nothing to show for it but the prototypes.
The Commemorative Air Force, operator of Fifi, the sole B-29 still flying, knows only too well the challenges associated with the bomber’s problematic Wright R-3350 engines. In 2005, following a series of engine failures, Fifi was grounded pending a complete power plant refit. As crew chief Dave Miller told AVweb, the R-3350 “was a poor design; it was rushed into service just like the airplane. It had a lot of problems with overheating—none that they could ever correct.” The CAF solved those problems by custom building hybrid engines that combined elements of two R-3350 models, and modifying Fifi’s engine mounts and cowlings to accommodate them.
After two years of work and the expenditure of $1.2 million, donated by Cavanaugh Flight Museum owner Jim Cavanaugh, the re-engined bomber returned to the skies in August 2010. This summer and fall it’s making appearances at EAA AirVenture and several other airshows across the country. At select stops a few lucky individuals will have the opportunity to take a short flight in Fifi. With prices ranging from $595 to $1,495 (for the bombardier’s position), it’s an opportunity that doesn’t come cheap—but once-in-a-lifetime experiences rarely do. Visit cafb29b24.org for more info.