Nice find DV303 but the real killer is that it has the same oil consumption as a four stroke engine.... That means extra maintenance, oil filters, de-carbonizing piston heads, injectors and needs even tighter air filtration to keep the small air intake holes on the upper end of the cylinder sides clear.

Keep in mind that the US Army as well as other services keep a number of "in the works items" visible while others are kept dark and sometimes without the inventors knowledge. Remember the US patent Office reserves the right to use a technology without notice if it is in the nations best interest. The inventor will get paid at some point but nothing public.