Imessage won't send texts as SMS until it times out and says a message can't be delivered

When I send a text without wifi, my phone plan has no data so Imessage won't be able to send a text like that, but it tries anyway for a WHILE and I am only able to send as SMS after it fails to send. I have send as SMS enabled, but even so. Is there any way to make it so Imessage will always send as SMS if I am not connected to WIFI?