Side A: “Wind increasing in volume. Get no chance to . . . ”  These were the last words from the doomed Navy airship Shenandoah, caught in a violent storm and crashing 7 miles southwest of this spot near Ava at dawn, September 3, 1925. Fourteen of its crew were killed. While souvenir hunters stripped the wreckage, a nation questioned the value of huge, rigid dirigibles, the last crashing in 1935. Smaller blimps replaced the dirigible as America’s lighter-than-air sentinels of the sky.