It seems to me that your wing needs additional angle of incidence.

Read these threads:

http://www.rcuniverse.com/forum/m_92...tm.htm#9281709

http://www.rcuniverse.com/forum/m_99...tm.htm#9961798

You could try shimming under the leading edge, in very small increments and testing.

The wing will adopt the same AOA to sustain level flight in balance, but the tail will rise up and the downthrust will increase.