I just finished modifying a .15 slow poke into a twin. The build thread is here: [link]http://www.rcuniverse.com/forum/m_8872575/tm.htm[/link]
My question is if the nacelles are only on the top of the wing do i need to subtract the area they cover when i do a wing loading calc.
Any advice would be great!

[link]http://www.rcuniverse.com/forum/m_8872575/tm.htm[/link]

There's no need to worry about the reduction in wing area. It's minimal and the nacelles will still supply some of the lost lift just from their surface area. For example when wing area is calculated it always includes the fuselage area except in extreme cases such as scale modern jets or in special cases where the fuselage width is quite a size in comparison to the wing span.

Thanks for your reply. I'm hoping that the high lift airfoil of the slow poke will be enough to overcome the extra weight.