Stirling or pulse jet?
You can always look into the thermodynamics of them.
Also whats your intented major Ryan? I looked up PLU and it mentioned 2 years at that school along with 3 at an engineering school... just curious how that works. Would you transfer to UW, WSU, or GU or some other 4 year? Do you have a degree after 2 years at PLU, I saw it mentioned something about a physics minor.