Career
Papp was issued several United States. patents for these inventions, including his noble gas fuel mixture. The engine continues to be considered by many scientists as a hoax. Papp"s poor physics theoretic background is demonstrated in the abstracts of the patents, which have been criticized by Richard Feynman.
Papp presented to an audience, including Feynman, an ill-fated demonstration in 1966, in which his engine exploded, killing one man and seriously injuring two others
Feynman"s conclusion was that Papp was a fraudster and the explosion an attempt by Papp to avoid discovery, although he notes that Caltech settled with Papp out of court. However, recently, Russian Gries, a private researcher who works for the company RWG Research, claims to have replicated the principles of the Papp noble gas engine with positive results.