Aircraft certification questions.

Howdy,

How does FAA type certification relate to intellectual property
rights? For example: everything in an O-235 has been out of patent for
years now. Same with old aircraft designs. Is there any reason why
somebody couldn't tool up and start ripping out O-235s, and selling
them new?

I ask because it seems weird that a dozen or so companies are
designing new engines from scratch that are only marginal improvements
over the old ones. Yet nobody reverse engineers and manufactures
out-of-patent engines to fill demand instead.

Does the FAA type certification trump the USPTO when it comes to
patent law? I can't emagine that such an arrangement would ever hold
up in a high court. The FAA can't just spontaneously dictate that it
owns every peice technology ever used in aviation, and that you can
only profit from public domain technology if it says so. Or do they?

I'm not knocking the FAA's safety interests. But public domain is
public domain. If I can make a 1948 mousetrap and sell it, why not a
Continental Engine?

If anybody can refer me to documentation on this or the section of law
or regulation that pertains to it, I'd be quite appreciative. I can't
emagine such a law exists. But I also can't understand why there is so
much reinvention of the wheel.

-Thanks in advance !
-Matt