The Consolidated PT-8 was an experimental version of the PT-3/ O-17 family powered by a Packard diesel engine.
Two XPT-8s were produced, both by converting existing aircraft - the XO-17A and a standard PT-3A.
The XO-17A was a single version of the O-17 advanced gunnery, photographic and radio trainer that had been given a R-790-3 (J-5C) engine for use as a demonstration aircraft for export orders. It became the XPT-8 after it was given a 220hp Packard DR-980 diesel radial engine.
The Packard DR-980 was a nine-cylinder air-cooled diesel radial engine. It was economical to run and reliable, and in 1929 powered the long distance first cross-country flight of an American aircraft, from Detroit to Langley Field. In 1931 a Bellanca CH-300 powered by the type set an endurance record of 84 hours and 32 minutes.
Despite these positive features the DR-980 suffered from excessive vibration and produced more unpleasant fumes than petrol engines. As a result the type wasn't a success and only around 100 were produced.