Jack Northop found that Jack-Northop-designed flying wings - may they be jet-driven or propeller-driven - had stability issues.Jack Northrop found that jet flying wings without fly by wire and computers had stability issues
Dozens if not a couple of hundred pilots who flew Horton designs of that era and not only the Ho IX or 229 as well as its un-engined V1 test-glider but also their numerous competition gliders - motoriized or not - or the Ho VII training plane i.e. might tell ... told a somewhat different story.
The necessity of fly-by-wire of the actually build US-planes was caused rather by their unareodynaically forming due to oh soo hyped stealth-tech.
... aside of Northop NOT being the one and only areodynamical pope and the often not-made-invented-here attitude of so many defenders of this thesis.