The Douglas TBD Devastator
There was an issue with this plane and it was not slight. This plane cased fatal accidents. It was only able to release a torpedo if it was flying straight and at a speed of 115 miles per hour. They launched 41 torpedos but only managed to shoot six.
The LWS-6 Żubr
Even if a plane is ugly that is no indicator that it will not be successful. Well, when it comes to this one then its an exception. This plane was created just before World War II and was eventually used for training usage. Four different LWS-6 Żubr planes were taken by the Soviet Military when Poland was invaded.