I am doing an Optimal Capital Structure project for my Fin Man class, BUS 5440. We have a spreadsheet that calculated based on various mixes of debt and equity, i.e. 5% D to 95% equity, 10% D to 90% E. I did my WACC project last week on General Dynamics and determined they were at 14%D and 86% equity. Really the only variable we need to determine is the required rate of return on debt. The textbook says this information normally comes from investment bankers. One video says you can get this data from morningstar.com.

How do I find information for r debt? Any guidance here would be much appreciated.