[Moonman62]

From Wiki:

The RQ-170 has a flying wing design containing a single (as yet unknown) engine and is estimated by Aviation Week as being approximately 66 feet in wingspan.[10] Its takeoff weight is estimated as being greater than the RQ-3 DarkStar's, which was 8,500 pounds. The design lacks several elements common to stealth engineering, namely notched landing gear doors and sharp leading edges. It has a curved wing planform, and the exhaust is not shielded by the wing.[10] Aviation Week postulates that these elements suggest the designers have avoided 'highly sensitive technologies' due to the near certainty of eventual operational loss inherent with a single engine design and a desire to avoid the risk of compromising leading edge technology.

[tanknetter]

Aviation Week postulates that these elements suggest the designers have avoided 'highly sensitive technologies' due to the near certainty of eventual operational loss

The problem with the Aviation Week postulation(s) is that while they are observationally correct, for the most part they don't represent "sensitive technologies".

For instance, anyone looking at public-source pictures of stealth aircraft know not only about faceting edges, but also that they are generally faceted at the same angles. Bill Sweetman, who is Aviation Week's stealth guy (or at least used to be) quantified this practice two decades ago with one of his first analyses of the F-117.

My theory on the RQ-170 is that, like the Predator, it was really just a technologies demonstrator that was pressed into production service to fulfill an immediate need.