Create simple UV Map for .DAE model

I have a .DAE model that is 20 instances of one object. I need a UV map applied to the object so that I can change the textures of the instances of the object in Unity. The object is a hemispherical equilateral triangle. Combined the objects create a sphere. The the bottom edge of the UV map needs to line up with one side of the triangle with no clipping (wrapping with the curve of the triangle). The UV map needs to be based on a square and the top left and top right corners will be clipped as it is a triangle. This should be very straight forward for anyone who is competent with UV mapping and only take like 5 minutes.