you're right. in the paper he is simply doing F2-F1 to give the thrust without any mention of the surface area of the cone walls. he mentions constructing the

you're right. in the paper he is simply doing F2-F1 to give the thrust without any mention of the surface area of the cone walls. he mentions constructing the cone to give a "reflection free transmission" which is impossible. i guess junk science is right. oh well. from page 6: Note that the reflection-free interface, with matched wave impedances , will ensure no forces are produced at the interface. <-- that doesn't sound possible.