RE: World Models 42% Ultimate Biplane
Hi Tom,
Those are difficult questions to answer. The plane's structure was not likely designed to handle much additional weight. In general, use the watts per pound rule and try not to go heavier than 60w/lb. Since you are not performing aerobatics, the symmetrical wing is adding unwanted drag.
Look at the large 12' Telemaster design at [link=http://www.hobby-lobby.com/12_foot_telemaster_arf.htm?pSearchQueryId=1015086]Hobby Lobby[/link]. This beast was designed to haul and lift.
Good luck!
Larry,
You won't have any problems with that combination as they have a great track record.
Regards.