They're suppose to be flat, but i don't think a slight postive pitch would cause any problems(i never could get mine flat)
well like he said they paddles arent supposed to have pitch. there supposed to be flat. most newbies make the assumption that they are suppsoed to produce lift. they provide better control response. for the best flying blade they must have a pitch of 0 wheneverything is level. This is very very important.