Author Topic: Keeping oil off of your main spar  (Read 5766 times)

Bill Poynter

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Keeping oil off of your main spar
« on: March 25, 2012, 12:19:43 PM »
Most of us have experienced small engine oil leaks that invariably end up on the bottom of the plane.  The visible oil on the bottom of the Cadet is easy enough to clean up and does little harm.  Unfortunately, because of the design of the bottom panel immediately behind the firewall, a lot of the oil also runs inside the fuselage.  This is probably a lot of the reason for Service Memo #19 regarding oil soaking of the main spar.

Iíve found that if you seal the leading edge of the aluminum panel where it joins the firewall, almost no oil enters the area above the panel.  I used the same type of sealant that the Bellanca factory recommends.  Itís automotive panel sealer and it's available at automotive paint supply stores.  3M makes a large selection of panel sealers.  Be sure to pick one that says itís resistant to oil.  Hereís a link to an article on selecting a suitable seanant: