Aircraft download technical problems

Hi all!
I've had some technical problems with FSX aircraft downloaded from simviation, so if anybody can help it would be greatly appreciated. On using some aircraft in the Free Flight mode, after selecting the aircraft it goes to the options screen as normal. The aircraft then appears in the 3D rotating window at the bottom of the screen for a fraction of a second, and then the whole 3D aircraft viewing screen goes white. If the Free Flight is loaded up, the virtual cockpit appears only as a white screen, but external views work, again only for a fraction of a second. This has happened with the Sea Hurricane, the A6M2 and the MD500. Can anybody please help?
I've had some technical problems with FSX aircraft downloaded from simviation, so if anybody can help it would be greatly appreciated. On using some aircraft in the Free Flight mode, after selecting the aircraft it goes to the options screen as normal. The aircraft then appears in the 3D rotating window at the bottom of the screen for a fraction of a second, and then the whole 3D aircraft viewing screen goes white. If the Free Flight is loaded up, the virtual cockpit appears only as a white screen, but external views work, again only for a fraction of a second. This has happened with the Sea Hurricane, the A6M2 and the MD500. Can anybody please help?
