Is it actually possible to throw knives in a straight line?

It can be done, but it takes WAY more skill.

A non-spinning knife is not stable.

The release is very critical.

Weight and balance allow a throwing knife to hit its target because in mid flight it goes blade first because of the weight.D

Back away from the TV and Video game console once in awhile and peak outside in the real word. Ninjas only exist in cartoons and super hero's for toddlers.D

at one time I wanted to learn how to throw. what I read a thrown knife spins 1 revolution every 9 feet. I could make the pocket knives stick out to 27 feet but never had accuracy at even 9 feet. after destroying a few knives I quit. I think they have to spin. jesse

It's possible..ask a ninja..

Edit: also to D, ninja do exist.

http://en.wikipedia.org/wiki/Ninja

Just ask any Ninja.

yes, I have known at least two people who can throw knives accurately underhanded this way.........Not me I throw over handed and they spin.

EDIT: D obviously you have never heard of the " triad"