I would suspect it has a pretty low Vne what with the fixed slatted wings, struts and all the angular window surfaces.
That particular FG aircraft has a couple of goodies I borrowed from the Fokker 50, the EEP panel has a series of buttons to set the engine's governor for takeoff, go-around, cruise, and approach regimes, clickable with a mouse.
Despite the drag, you can get the Uber-Storch to blast along at 140 knots, but it really slurps down the limited volume of Jet-A. Where it really shines is at loafing around at 50 to 70 knots with a notch of flaps set and then throttling up to climb out insanely.
I added wing struts to the Uberstorch they do seem a bit on the small side.