Work on a third prototype was abandoned because of the failure of the first two aircraft .
The second prototype continued in use until at least March 1919 carrying out test flights in futile attempts to solve the problems of the Dragonfly .
Work on a third prototype was abandoned because of the failure of the first two aircraft , although the second prototype continued in use until at least March 1919 carrying out test flights in futile attempts to solve the problems of the Dragonfly .