Hello again,
Yes, the pipe hanging on the side of this admitedly short fuselage made a mess of loop trimming in both cases I saw: probably a matter of disturbed air on the right stab half.
It is a fairly short fuselage and the aft end of the pipe is awfully close to the stab.
Maybe if you spend some time to get the pipe lined up with the relative airflow (raising or lowering the tail of the pipe) then it will work.
I'd hate to have to cut multiple holes for the pipe mount, though.
Regards,
Dean