The little 25-30HP KFM engines used in the Monnett Moni and a few other airplanes developed a reputation for twisting the front of the crankshaft off in flight. Even though the design problem was apparently fixed by the company, the engine never overcame the negative publicity from a few inflight failures. The Pou du Ciel developed a habit of diving uncontrollably into the ground, killing more than one pilot. The problem was identified and completely fixed within a short time, resulting in a perfectly good aircraft. But the Pou never overcame the reputation and bad publicity, even today 80 or 90 years later. After the Hindenburg disaster, the LTA airship became untenable and indefensible overnight, and despite the fact that they understood the issue and never used Hydrogen gas again, the public trust and popularity of the airship was never regained. The airship/bimp was relegated to the history books and 5 or 10 promotional vehicles flown by Goodyear for many decades. (Only now, 80 years later, are they starting to be of serious interest again.) Salvatore Occhipinti, my 10th grade history teacher, made an old old saying into a double-entendre the day before he gave us the final exam: "Those who do not know history are doomed to repeat it".