Trim Tabs

Friday was a terrible day for aviation and for air racing in particular. When the elevator trim tab separated from the airframe, Jimmy Leeward lost control of his modified P-51 air racer, The Galloping Ghost, crashing into air race spectators.

Leeward, 74, had been flying for a long time and, according to his Facebook page, racing since 1974. In addition to his interests in air racing, Leeward created the Leeward Air Ranch near Ocala, FL catering to pilots who really liked flying, building airplanes, and sport aviation in general.

The Galloping Ghost began life as a fighter aircraft delivered to the Army Air forces in December 1944. After a short stint in the military, the Army declared her as surplus in October 1945.  She went into storage at Walnut Ridge, AR until March 1946 when a couple of would-be air race pilots, Bruce Raymond and Steve Beville, purchased the airplane for a mere $3500 from the government.

Many modifications followed to lighten the airplane, increase the power of the engine, and eliminate any unnecessary drag. The National Aeronautics Association approved the use of the race number “77” for the airplane and the pilots named her The Galloping Ghost in honor of football player “Red” Grange. At the Cleveland Air Races later that year, The Galloping Ghost took fourth place in the Thompson Trophy Race.

Since then, The Galloping Ghost has done very well as a racer in Cleveland, and later at Reno. Jimmy Leeward acquired the The Galloping Ghost in the 1980s and flew a little before restoration work began. As with all projects, it was a long process. Leeward had hoped to have the airplane ready for the races in 2005, but it was another three or so years before she was race-ready.

After the crash on Friday, photographs surfaced of the final milliseconds of the airplane’s existence. From what witnesses said, Leeward seemed to have trouble in the race and pitched out above the other racers. Many speculated if pilot error was involved, or if it were a medical issue. Neither was the case.

In the photographs taken of the last moments of the airplane’s fight, it was clearly evident the trim tab on the left elevator had separated from the airframe. At airspeeds in excess of 400 knots, the flight controls may have deflected well out of the realm of normal causing excessive g-loading. In one photo, Leeward is not visible in the canopy and the explanation is that his seat had failed.

At high speeds, a flight control malfunction can be a nightmare.

Even at low speeds, they are dangerous.

The 1959 Cessna 150 I used to obtain my private ticket decades ago, suffered a similar fate. My instructor would preflight his airplanes in the morning at first flight, and then depend on the students for preflighting later in the day. At some point on the day of the mishap, the locknut holding the trim tab actuating rod in place came loose.

As the instructor and student climbed out, it completely separated from the airplane and that set up an aerodynamic flutter in the trim tab. The flutter then transferred to the elevator, and then to the horizontal stabilizer. This led to the torsional twisting of the fuselage that eventually popped every rivet in the fuselage aft of the side windows.

This happened at 200 feet agl and the old instructor knew exactly what was causing the vibrations and flutter. He immediately reached down and turned off the fuel, pulled the mixture to idle cutoff, closed the throttle, and secured the magnetos and master switch. All the while he was doing this, he was working his way to a landing in the pasture next to the cypress dome at the end of the runway.

The airplane was totaled, but the two on board were not hurt. This made it a win situation. You can always replace hardware, but humanware is another question.

The next time you go flying, pay particular attention to the trim tabs, along with the other flight control systems.

-30-

©2011 J. Clark

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