I don't know why, but my last plane is not fast, but I made it to reach over 600 km/h. It has very good aerodynamics, without a single red part, the weight is average for an airplane with several fuselages. But even so, it does not pass 360 km/h, even having a 3500 HP engine (modified in xml).
Please, I had to put a jet engine in so it wouldn't stall after making a sharp turn, but i don't want to keep the jet on it so it gets fast.
The plane is called Scaft FV-724 Mk.Ia Spreadshot
Ignore all this, i discovered the wings done more drag than a parachute