I am officially going to continue with flying wings after @General360 and @SledDriver gave me some inspiration by helping fix my problem. Massive thanks to @SledDriver for fixing my Northrop N9M and @General360 for helping diagnose the problem, and giving me a way to fix it in future builds. Credit also goes to @randomusername for criticising my plane and pointing out flaws (I really do appreciate it, it helps a lot) and @Tang0five for giving me more issues with the plane. Without all of the users I mentioned above, my N9M wouldn't be able to fly.
@EpicPigster1 No problem. SimplePlanes makes it very easy to make pretty much anything fly well as long as you follow some basic principles. Someone needs to put together a tutorial on how to make planes that fly well.
@randomusername It is quite stable. However, it still yaws ever so slightly to the right under 240mph, which isnt a big deal. By the way, to me, criticizing is a good thing! it helps us improve :)
Thank you @General360 and @SledDriver so much for helping with the design. I can actually make working flying wings now, and I will be able to diagnose problems myself without needing help (unless the problem is a really odd one)! :D