On Sunday, December 6, 2015 at 12:53:04 PM UTC-5, Jonathan St. Cloud wrote:
What are the draw backs of using the DG Mandel type air exit as this seems more viable than the ES style vent?

It very much depends on whether there is a low pressure area on the fuselage that will provide the suction needed to be effective. If there is, the next issue is whether it is in a place where the structure will permit installation as well as being able to provide and install the inner portions of the system that bring the airflow smoothly up to free stream speed.
I repaired 2 holes in a Discus 2 resulting from 2 failed attempts.
UH