I have a question about the history of soaring... (I'm not asking a practical serious question.)

Has anyone tried and/or had any luck with a 'slow burn single use' solid rocket in a glider? It would have the advantage of high energy density, low drag and quick start. I suppose that it might melt something important if it were were mounted on the fuselage. What about a wing mount close to the root?

I know this idea sounds crazy, but a pop-up jet sustainer strikes me as only slightly less outrageous.