Ralph M. Heintz holding Radiotron Tube, August 1927

Ralph Heintz holds a 50-watt 'Radiotron' tube from an early short-wave airborne radio transmitter. Heintz had earned a reputation for innovative electromagnetic design suited to the needs of the adventurous, on land, sea or in the air. This light-weight radio was on the Pabco Flyer, one of several contestants in the August 1927 "Dole Air Race" from Oakland, California to Honolulu, the longest and most dangerous air event to date. After the Pabco Flyer crashed twice on takeoff, the radio was installed in the Dallas Spirit. Listeners on land as well as ships at sea could hear the transmissions from the Dallas Spirit while they looked for planes of other contestants, presumed lost at sea, and finally, to the sounds of the fatal tail spin of the Dallas Spirit. The tragic air race--six men and one woman lost at sea--underscored the need for air navigation instruments and improvements in portable radio equipment.