I have had three Northstars over the years, though all were built by other people. Great fun models, all since sold on in working condition.
On my latest model I made a few changes, well a lot really. It's hard to say because I never built one so I don't know exactly how they go together.
But I changed the wing section from symmetrical to a slightly thinner NACA 5 digit with just a little camber.
I increased the span a little, and cut it from foam covered with obeche veneer.
I changed the nose shape, by making it longer, and made up my own structure for the tail with a bolt-on tailplane.
I put in a cockpit with a pilot and added a rear decking
But the main change was adding foreplanes. They are coupled to the elevator, and aslo act as airbrakes on approach. (second photo)
Power is an Irvine 53
I changed it so much I now call it a "Lochstar" but its derivation is obvious.