What the hell do you not understand?
Making it in a arc will perform the SAME THING as the shooting it straight out. Look at it this way:
Hog = >
Flame = Line
(too lazy to [ninja] the dots.)
Frame 1
.../.\
../...\
/>....\
Frame 2
.../.\
../...\
/.>...\
Frame 2
.../.\
../...\
/..>..\
Frame 3
.../.\
../...\
/...>.\
Frame 4
.../.\
../...\
/....>\
Frame 4
.../.\
../...\
/.....\
.......>
UH OH
DIRECT HIT
WEAPON DESTROYED.