Just a couple thoughts. There is actually no such thing as vacuum. Vacuum is by definition the absence of air.
What there is, is 15 psi of atmospheric pressure (at sea level) driving air into any place with lower pressure. So the teacher was correct.
Gunner 500, I am on my phone. So cannot copy and paste. I was quite recently perusing the history of Detroit Diesel and the websites listed many two stroke naturally asperated engines in small HP applications.
