Wing Oil  Cooler install (1)


I wanted to install the cooler in the wing for a number of different reasons.


  1. 1.I wanted to remove it from the engine compartment to allow easier access and maintenance of the bird.  One NEVER needs to mess with the cooler once installed so why have it in the way?

  2. 2.I personally like a separate ducting system for the cooler as it  allows one  to optimize the oil cooling separately from the engine cooling.

  3. 3.I wanted to have the best D/P across the  cooler which allows you to reduce inlet/outlets to reduce drag.


After analyzing the stress of the wing in the proposed cooler area (due to cutting of holes in the wing skins, I determined that the installation would not be detrimental to the plane.  The wing skin in this area is subject to only a slight torsional loading, as it is between the bolt holes and most of the torsional skin stress is applied at the outboard bolt area.   Very little torsional loading occurs in the proposed cooler area  As with any hole cut in a flat panel, if one strengthens the opening, stress can be directed around the hole (in simple terms) similar to designing for a hole cutout in any stressed panel design.  The reinforcement I designed into to this cooler design MORE than compensates for the the removal of the skin.  In subsequent post install flights the plane was tested at 250 kts (smooth air) and in strong turbulence and flight maneuvers.  I am very happy with the install and my cooling is spot on all the time. 

I AM NOT RECOMMENDING ANYONE INSTALL THIS SYSTEM.  This is an effort to document my install for others to review and determine if they would like to test the design.

The Install.......

My first step in the process of installing my “In the wing oil cooler” was to check if the foam in the wing wing would be able to handle the heat.  So I tested samples at various temperatures to see what happens.  At 180F there is no change in the foam and a slight swelling begins at 190F.  As you can see severer distortion occurs the higher the temp.  I figured the oil cooler compartment would never get this high with air circulating around the cooler. 

Step two was determine the best placement of the inlet/outlets.  After a about 15 flights tests in my EZ (using a air speed indicator between the upper and lower part of the wing) I founding the best outlet for the cooler to be about 6-9” aft of the spar on the top.  Perfect as the size of the cooler is the small space is a determinate factor on the outlet ducts.  The optimal outlet point (174 mph) occurred at 9” aft of the spar (as measured from the LE of the spar).

Step three was to determine if the oil cooler would fit into the wing without to vertical of an orientation. .

Everything fit nicely in my wing template.  I can avoid the spar, torque tube and the nylaflow tubing (rudder) so the install would work.   Now I am ready to get started!