I claim no credit for the following (apart from editing out one or two possibly irrelevant bits), it comes from a friend who is an aerobatic hooligan and a Yak-52 owner...
Incidentally Houey, although you seem to be entirely correct about the Yak-52 flat spin - at-least according to my friend the Yak owner, I've professionally dealt with a number of issues that were "well known" such as the alleged Bulldog unrecoverable spin, which never stood up to rigorous scrutiny.
G
Yak spins well, but there is the risk of getting into a flat spin.
Particularly if you keep the engine at full bore. Flat spin usually results from a 'ballsed up' stall turn. Which is why we've banned that manouvre in the syndicate. There is a mild disinclination to not come out of it, particularly if you've got some power left on.
If your rear seat passenger is heavier than the front seat pilot, there is also an increased possibility of getting into a flat spin from a normal spin or ballsed up aero. This is due to rearward CofG. This is much more of an issue to recover from.
The biggest problem with recovering from a flat-spin is that it requires about 3000ft.
There are a couple of fatalities I know of in Yak52s from flat-spin
issues. First was in ***** where the rear seat passenger was a bloater. The second was at *****where a pilot decided to show how good he was at low level stall turns..... turned out he wasn't.....
The main thing about the Yak52 is the tendency to flick from a G-break or stall. This can rapidly lead to disorientation and either a flat spin or inverted flat spin.
However, you do get quite a bit of warning and if you cut the power wait until you recognise which way up you are, and then apply standard recovery techniques, its not an issue. In worst case scenario, you may need a little aileron in the recovery.
On approach we prefer to use about 1/3 power and use the glide slope on a curved approach, rather than 'dragging' her on. This ensures you remain above the stall and do not get behind the drag curve.