I'm a relative newbie to R/C and I fly powered so take my comments with a grain of salt.

Gliders are great and can soar for hours, but only under the right circumstances. You can hand launch a glider on flat ground and soar, however you would need to find a thermal right away and climb by gently circling inside of the thermal. A thermal is a rising column of warm air. Usually they occur over asphalt, packed dirt, or any surface that absorbs the heat and warms the air over it.

Without an engine your glider will glide like a paper airplane and not climb unless you can find a thermal or ridge lift. Ridge lift is sort of like a wave of air that is created by wind flowing over a ridge. People call it slope soaring because they stand on a slope and use the wave to keep the plane aloft.

Another option is to make a tow winch that will pull your plane to a high altitude and allow you to glide for a longer period of time. I'm sure you will find all the information you need in the gliders section of this site.

Synopsis: I think your expectations for hand launching your glider might be too high.

Hope this helps.

JakeC