Assertion: powered aircraft | /r/HasProperty | experimented
Facets:
value: occasionally
type: DEGREE
Source sentences:
text: Rocket-powered aircraft have occasionally been experimented with, and the Messerschmitt Me 163 Komet fighter even saw action in the Second World War.
text: Rocket-powered aircraft have occasionally been experimented with, and the Messerschmitt Komet fighter even saw action in the Second World War.