Bob Cook wrote:

If we are gonna play what if.....

What if there was no lift? (like a brick,)

Sure it would move because of gravity, but in what direction? Down! Not
forward!

That is correct and demonstrates a useful "thought exercise".


So tell me again how gravity imparts a forward force to a glider?

By itself it cannot. The presence of gravity *and* air are required for
gliding (forward) motion.


Although "no gravity is not possible,

Sure it is. Place your glider in outer space. Likely? No. Possible?
Certainly.


"no lift" is easily demonstrated:

And lift(as we are using the term) without gravity is not possible.

Regards,

-Doug