If it has to be able to fly in an acceptable manner under it's own power then that may change things. The maximum weight will then be set by many factors based on teh available power, size of the model, flight parameters that the owner/pilot is willing to tolerate and a few others.

Bottom line is that the airframe would have to be small enough and clean enough to have the same amount of drag force at that speed as what the weight of the model is. There's just too many unknowns to say yes or no for a practical example. But my gut reaction is to say no. This is based on the speed record set by a glider back in the 70's in Austria. The airframe was as clean as you're going to find and the record was set at about the 240 mph range. Given that the timing run through the traps was required to be basically level I have no doubt that the pre trap dive speed was well up there. Possibly in your 275 mph range. But this was a very clean design with an arrow like fuselage and very thin wings that were molded very accuratley. A typical jet style model with the usual visual styling items such as air intakes and canopies and gear doors and other "stuff" on it will have a much higher drag coefficient so it would require quite a bit of weight to counter the drag of the airframe.

PS: Larry, I hope you realize that you are mixing up acceleration with terminal velocity. Two different things. Even Leonardo Davinci was lucky that his little experiment at the Tower of Pisa used two items that had enough density that they did not reach a fair portion of their terminal velocity value before they hit dirt or he would have been quite embarrased. A rock and a feather have the same INITIAL acceleration but their terminal velocities are quite a bit different thanks to air drag.