April 2, 2010 HOME



After cutting out the openings for the louvers, Bill started to work on a system (method?) to extract the cooling air and exhaust while reducing drag.  The idea isn't new.  In fact, it is copied from Larry Vettermans website.

He laid up some blocks of foam that I wanted to get rid of anyway and he carved them to roughly the shape that Larry's system appeared to be.  It wasn't quite the result I was looking for.

When the shape was in the ballpark, Bill did a very thin layup of fiberglass to make a flexible model as a starting point for fit.

Because the fiberglass is thin and flexible, it can be easily cut  and bent to finalize the shape.  Finalize?  No, we're a long ways out from there!

Looking forward toward the ends of the exhaust pipes, you can see the idea shaping up.  At this point it doesn't seem quite right.  There is more shaping ahead.

















The whole idea here is to carry the airflow smoothly under the belly of the airplane without the drag creating suck-back that often occurs at the exit point.


While Bill was having fun with the new fiberglass creation, I center hung plumb bobs at each end of the airplane and snapped a chalk line to establish a good centerline.

Equal measurements from the centerline to the center point behind and in front of the wheel pant puts the wheel pant in line with the direction of flight of the airplane.



I used plumb bobs at both ends to assure precise alignment.



Previous Day | HOME | Next Day

 The page contains Kathleen Evans RV-7l of Redding CA.