Thank you. I need some time to process this information and I will come up with many questions. But all my questions I need to back up with pictures, so there's no confusion in my head. I am sure this is like a walk in the park for most of you guys, but not for this Russian. I need my pictures.Now Eugene, on to your problem. You have a strong taper going into the prop inherent to the layout. This tends to cause separation that is not only draggy by lowers prop efficiency a bunch too. Ouch, Ouch!
The way I understood, that part of fuselage under the wing in front of Propellers is under constant vacuum during cruise and with a few vortex generators = problem is fixed.
Picture below is the shape, cross section right under the wing. I was told that this is almost acceptable.
Picture below, is cross-section of fuselage at propeller tip. I was told that it doesn't really look that bad after VGs installed for 80-100 MPH cruise. Wrong?
The bottom part of fuselage really need help and there's no questions about it. One time I was thinking about different shapes. This is one of my pictures below